USE OF A RARE EARTH FOR THE REMOVAL OF ANTIMONY ANDBISMUTO FIELD OF THE INVENTIONThe invention relates generally to a process for removing one or more contaminants from an electrolyte solution and more particularly to a process for removing the one or more contaminants in an electrorefining solution using rare earth metals.
BACKGROUND OF THE INVENTIONElectrometallurgy is a process to recover a metal from an electrolyte solution using electricity. The electrometallurgy process involves passing an electric current through the electrolyte solution to extract or purify the metal. The electrometallurgical process to extract the metal from the electrolytic solution is typically called electroextraction, while the process to purify the metal by passing the electric current through the electrolytic solution is called electrorefining.
Electrorefining comprises dissolving the metal at the anode and re-depositing the same metal at a cathode in an electrochemical cell. In electrorefining, the metal that is refined is oxidized at the anode and enters the electrolytic solution as a cation according to the following semi-cell reaction:M °? n + + n e \ (1)The oxidation process produces electrons at the anode. The number (n) of electrons (e ~) produced is determined by the cationic species (Mn +) of the metal (M) produced electrochemically.
Typically, the anode contains different species of metal that is electrorefined, these species may have higher, lower or similar metal oxidation potentials that are electrorefined. Species that have higher oxidation potential than metal that is electrorefined are considered to be more noble. The most noble species, such as noble metals, do not oxidize at the anode and do not enter the electrolytic solution during the anodic process. As such, a sludge containing noble metal is formed during the anodic metal dissolution process. Species contained within the anode that have oxidation potentials substantially similar to or oxidantly more active than the metal are typically oxidized and enter the electrolyte solution as contaminants during the anodic dissolution process. These contaminants are present within the electrolytic solution as dissolved species and accumulate within the electrolyte solution. More importantly, these contaminants can interfere with the cathodic deposition of the metal.
The process of cathodic re-deposition of the metal is represented by the chemical semi-reaction:Mn + + n e "? M ° (2)where, the dissolved cationic species (Mn +) of the metal is reduced to the elemental metal (M °) by taking n electrons (e ~) at the cathode. Compared to the anode, the cathode contains a substantially purer form of the metal. The cathodically re-deposited metal is substantially free of the noblest metals and / or contaminants previously contained within the anode.
Copper is a metal that is commonly electrorefined. The noble metals commonly recovered in copper electrorefining are gold, silver and platinum group metals. Pollutants, other than noble metals, are typically arsenic, antimony, bismuth, selenium, tellurium, lead, tin, iron, cobalt, zinc, and nickel.
The presence of arsenic, antimony and bismuth are problematic materials in copper electrorefining. Arsenic, antimony and bismuth are typically contained in copper anodes used in copper electrorefining. Copper, arsenic, antimony and bismuth have similar standard reduction potentials. During the electrorefining process most of the arsenic and some of the antimony and bismuth contained in the copper anode dissolve electrochemically in the electrolytic solution.
As such, the concentrations of arsenic, antimony and bismuth within the electrolytic solution are increased. One or more of arsenic, antimony and bismuth can be cathodically electrodeposited with copper affecting the quality of copper, such as the copper grain structure and copper purity level of electrorefined copper. Therefore, it is important to control the concentration of arsenic, bismuth, antimony and other contaminants during copper electrorefining.
BRIEF DESCRIPTION OF THE INVENTIONThese and other needs are addressed by the various embodiments and configurations of the present invention. This description is generally related to the removal of target material from an electrolyte solution and the stabilization of one or both of the target material and the electrolyte solution.
One embodiment of the present invention is a process comprising:(a) receiving a rich feed solution having a target material and a valuable metal;(b) electrodepositing the valuable metal onto an electrode to form an electrolyzed solution, wherein at least the majority of the valuable metal is electrodeposited on the electrode; Y(c) contacting at least a portion of at least one of the rich feed solution and the electrolyzed solution with a binding agent containing rare earth to form an insoluble binding agent loaded with target material, the agent of insoluble attachment loaded with target material comprising at least the majority of the target material in the at least a portion of the at least one of the rich feed solution and the sterile solution, wherein the target material, in the agent Insoluble fixation loaded with objective material, forms a composition with the fixing agent and the target material is at least one of antimony and bismuth.
In one configuration, the process further comprises separating the insoluble binding agent charged with target material from at least one of the rich feed stream and the electrolyzed solution to form a purified stream. In another configuration, the process further comprises at least one of recovering the target material and recycling the purified stream to the electrolysis cell. The electrodeposition process is one of electroextraction or electrorefining.
Preferably, little, if any, of the valuable metal is removed from one or both of the rich feed stream and the electrolyzed solution in the contact stage (c). Valuable metal is a metal that has an atomic number of 22-30, 40-48 and 72-79.
In one configuration, the process further comprises contacting the insoluble binding agent charged with target material with a separation solution to dissolve, solubilize or otherwise displace the majority of the target material in the insoluble binding agent loaded with target material for forming a charged separation solution and the sterile insoluble binding agent, wherein the separation solution comprises at least one of a strong base, an oxalate, ethanedioate, a strongly absorbent exchange oxyanion, a reducing agent or reducing agent, and an oxidant or oxidizing agent. In another configuration, the process further comprises cyclizing the sterile insoluble binding agent to the contacting step (c), wherein the sterile insoluble binding agent is brought into contact with one of the rich feed stream and the electrolyzed solution to form the insoluble fixing agent loaded with target material. In yet another configuration, the process further comprises removal of at least the majority of the dissolved target material from the charged separation solution.
A preferred embodiment of the present invention is a process comprising:(a) forming, from an electrolytic cell, an electrolytic side stream comprising a target material and a valuable metal, wherein the electrolytic side stream has a first concentration of target material;(b) contacting the electrolytic side stream with an insoluble binding agent to form an insoluble binding agent charged with target material and a purified electrolytic stream, the insoluble binding agent comprising at least one yttrium, scandium and a lanthanoid, the insoluble fixing agent loaded with target material comprising the majority of the target material in the electrolytic sidestream, wherein the target material, in the insoluble fixing agent loaded with target material, forms a composition with the insoluble fixing agent; Y(c) cycling the purified electrolytic current to the electrolytic cell, wherein the purified side stream has a second concentration of target material substantially less than the first concentration of target material.
In the contact stage (b), substantially little, if any, of the valuable metal is removed from the electrolytic side stream. Preferably, the valuable metal is copper.
In a preferred embodiment, the target material is at least one of arsenic, antimony, bismuth, tin, lead, selenium, tellurium, platinum, iridium, ruthenium and rhodium. In another preferred embodiment, the target material is an oxyanion. In a more preferred embodiment, the target material is an oxyanion of at least one of tellurium, selenium, bismuth, antimony and arsenic.
In one configuration, the insoluble fixing agent is a finely divided solid having a surface area of about 25 m2 / g to about 500 m2 / g.
In another configuration, the process further comprises contacting the insoluble binding agent charged with target material with a separation solution to dissolve, solubilize, or otherwise displace the majority of the target material in the insoluble binding agent loaded with target material. form a charged separation solution and the sterile insoluble binding agent. Preferably, the separation solution is one of a strong base such as an oxalate, ethanedioate, a strongly absorbent exchange oxyanion, a reducing agent or reducing agent, an oxidant or oxidizing agent.
In another configuration, the process further comprises cyclizing the sterile insoluble binding agent to the contacting step (b), wherein the sterile insoluble binding agent is contacted with the electrolytic side stream to form the insoluble binding agent loaded with objective material.
In yet another configuration, the process further comprises removing at least the majority of the dissolved target material from the charged separation solution.
In still yet another configuration of the process, the first and the second fixing agent are used. In a first step, the electrolytic sidestream comprises a stream carrying objective material, which has a first concentration of target material. The electrolytic side stream is contacted with a first insoluble fixing agent, such as an adsorbent or absorbent, to produce a first fixing agent carrying target material. The first contact stage removes most, if not all, of the target material from the electrolytic side stream. In a second contacting step, the first binding agent carrying target material is contacted with an alkaline separation solution ("release agent") to produce a solution rich in intermediate target material having a second concentration of the target material . The second concentration of target material may exceed the first concentration of the target material. The alkaline separation solution can be or include, for example, a leaching agent. Commonly, the second concentration of target material is a concentration approximately equal to the solubility limit of the target material (under the conditions of the second stage process). More commonly the second concentration of the target material is between about 0.1 and about 2,500 g / L, even more commonly between about 0.1 and about 1,000 g / L, and even more commonly between about 0.25 g / L and about 500 g / L. Finally, a second soluble or dissolved fixing agent is brought into contact with the solution rich in intermediate target material in an amount sufficient to precipitate most, if not all, of the target material as a solid carrying target material. The solid carrying target material can be separated from the solution rich in intermediate target material by any suitable solid / liquid separation technique to produce a separate solid for the waste and / or recovery of the target material and a separation solution for recycling to the second contact stage.
The insoluble binding agent, which includes the first binding agent, is commonly a particulate solid. The insoluble fixing agent (including the first fixing agent) is preferably an insoluble rare earth metal compound, more preferably an insoluble earth oxide comprising an insoluble earth compound, such as oxides, chlorides, carbonates, fluorocarbonates, hydrated or anhydrous rare earth silicates and the like. A particularly preferred insoluble fixing agent is Ce02. The fixative agent is particularly effective in removing arsenic that has an oxidation state of +3 or +5.
The second soluble or dissolved binding agent typically has a lower oxidation state than the oxidation state of the (first) insoluble binding agent. Preferably, the oxidation state of the second fixing agent is +3 or +4. The soluble fixing agent is preferably a soluble rare earth metal compound and more preferably includes salts comprising rare earth compounds, such as bromides, nitrates, phosphites, chlorides, chlorites, chlorates, nitrates and the like. More preferably, the soluble binding agent is a rare earth chloride (III).
The intermediary solution can include a valuable product. The valuable product is commonly any metal of interest, more commonly includes one or more of the transition metals and even more commonly includes a metal selected from the group of metals consisting of copper, nickel, cobalt, lead, precious metals and mixtures of the metals. same. All or a portion of the residual valuable product can be recovered from the intermediate solution.
Another preferred embodiment of the present invention is a process comprising:(a) forming from an electrolytic cell an electrolytic side stream comprising a target material and a valuable metal, wherein the electrolytic side stream has a first concentration of target material;(b) contacting the electrolytic side stream with a fixing agent to form an insoluble composition;(c) removing the insoluble composition from the electrolytic sidestream to form a purified electrolytic stream; Y(d) cycling the purified electrolytic current to the electrolytic cell, wherein the purified side stream has a second concentration of target material substantially less than the first concentration of target material.
In one configuration, the fixing agent is a non-rare earth salt additive. The non-rare earth salt additive is a non-rare earth metal that has a +3 oxidation and is substantially free from a rare earth. The insoluble composition is a precipitate formed between the target material and the non-rare earth salt additive. Preferably, the non-rare earth salt additive comprises one of boron, aluminum, gallium, indium, thallium and a transition metal.
In another configuration, the fixing agent containing rare earth is a rare earth salt additive. The rare earth salt additive is a rare earth that has a +3 oxidation state and a non-rare metal that has a +3 oxidation state. The insoluble composition is a precipitate formed between the target material and at least one of the rare earth and non-rare earth. Preferably, the non-rare earth material comprises one of boron, aluminum, gallium, indium, thallium and a transition metal.
In still another configuration, the fixing agent is a rare earth, preferably a soluble rare earth. The insoluble composition is a composition containing insoluble target material formed by contacting the target material and the soluble rare earth.
The electrolytic side stream contains a valuable metal. At least most, if not all, valuable material within the electrolytic sidestream is cycled to the electrolytic cell. In a preferred embodiment, the electrolytic side stream contains copper. At least most, if not all, copper within the electrolytic sidestream is cycled to the electrolytic cell by the purified electrolytic current.
Still another preferred embodiment of the present invention is a process comprising:(a) forming from an electrolytic cell an electrolytic side stream comprising a target material and dissolved copper, wherein the electrolytic side stream has a first concentration of target material;(b) contacting the electrolytic sidestream with a binding agent containing insoluble rare earth to form an insoluble binding agent loaded with target material and a purified electrolytic current having at least the majority, if not all, the copper contained within the electrolytic side stream, the insoluble binding agent containing rare earth comprising at least one of yttrium, scandium and a lanthanoid, the insoluble fixing agent loaded with target material comprising the majority of the target material in the electrolytic side stream, wherein the target material, in the insoluble fixing agent loaded with target material, forms a composition with the insoluble fixing agent; Y(c) cycling the purified electrolytic current to the electrolytic cell, wherein the purified side stream has a second concentration of target material substantially less than the first concentration of target material.
Preferably, substantially little, if any, of the dissolved copper is. Remove from the electrolytic sidestream in the contact stage (b). On the other hand, the preference process also includes:(d) contacting the insoluble fixing agent loaded with target material with a separation solution to dissolve, solubilize or otherwise displace the majority of the target material in the insoluble fixing agent loaded with target material to form a separation solution charged and the sterile insoluble binding agent, wherein the separation solution comprises at least one of a strong base, an oxalate, ethanedioate, a strongly absorbent exchange oxyanion, a reducing or reducing agent, an oxidant or an oxidizing agent.
In another configuration, the process also comprises:(e) cyclizing the sterile insoluble binding agent to the contacting step (b;(f) remove at least the majority of the dissolved target material from the charged separation solution.
Preferably, the sterile insoluble binding agent is contacted with the electrolytic side stream to form the insoluble binding agent loaded with target material.
In some embodiments, the target material will be present in a reduced oxidation state and this condition could be undesirable. In such cases, an oxidant may be contacted with the electrolyte feed stream to increase the oxidation state of the target material. Using arsenic as an example, the presence of arsenite could favor the use of an oxidant before the fixing agent is applied.
. In another embodiment, a process is provided that includes the steps of:(a) contacting an electrolyte solution comprising a target material with a soluble binding agent, the soluble binding agent comprising a rare earth, to form a composition containing insoluble target material comprising the target material and the rare earth; Y(b) removing the composition containing insoluble target material from the electrolyte solution to form a purified electrolytic solution.
The composition containing insoluble target material is typically in the form of a precipitate that can be removed as a solid. Preferably, the composition containing insoluble target material has at least about 0.01% by weight, to one more preferably at least about 0.1% by weight, and even more preferably at about 5 to about 50% by weight of the target material. The target material is commonly in the form of an anion containing oxygen with an oxyanion that is illustrative. Preferably, the target material is one or more of arsenic, antimony, bismuth, selenium, tellurium, tin, platinum, ruthenium, rhodium and iridium. The soluble binding agent, or precipitant, can be supported by a suitable carrier or can be unsupported.
In yet another embodiment, a method includes the steps of:(a) providing an electrolytic current containing a target material;(b) contacting the electrolytic current with one or both of the following:(i) a rare earth salt additive, the rare earth salt additive comprising a rare earth in the oxidation state +3 and a non-rare metal in the oxidation state of +3; Y(ii). a non-rare earth salt additive, the non-rare salt additive comprising a non-rare earth metal in the +3 oxidation state and which is substantially free of a rare earth; and forming a precipitate between the target material and at least one of the rare earth salt additives and not rare earth.
The non-rare earth metal can be any non-rare earth metal in the +3 oxidation state, with transition metals, boron, aluminum, gallium, indium and thallium being preferred, and the transition metals and aluminum which are particularly preferred. Preferred transition metals include elements having atomic numbers 22-29, 40-45, 47, 72-77 and 79.
The rare earth salt additive is, in a formation, a salt solution based on lanthanide, bimetallic. The non-rare earth salt additive, in a preferred formulation, contains aluminum in the +3 oxidation state. In a preferred formulation, the rare earth salt additive includes cerium in the +3 oxidation state and the rare non-ground salt additive includes aluminum of +3 oxidation state.
In still yet another embodiment, a method is provided that includes the steps:(a) providing an electrolytic stream comprising a dissolved target material and dissolved valuable product, the target material which is in the form of an oxyanion and the valuable product which is at least one of a transition metal;(b) contacting the electrolytic current with a rare earth fixing agent to precipitate at least the majority of the dissolved target material as a precipitate containing target material while leaving at least the majority of the valuable product dissolved in a electrolytic current treated, and(c) separating at least the majority of the precipitate containing target material from the treated electrolytic stream.
The present invention may include a number of advantages depending on the particular configuration. The process of the present invention can remove varying amounts of objective material as necessary to comply with the application and process requirements. For example, the target material removal process can remove high concentrations of target materials to produce a treated electrolytic current having no more than about 500 ppm, in some cases no more than about 100 ppm, in other cases no more than about 50 ppm. ppm. In still other cases, the process of removing target material can produce a treated electrolytic current that is no more than about 20 ppb, and in still other cases no more than about 1 ppb of target material. Insoluble rare earth / non-target material product can be classified as non-hazardous waste. The removal process of target material may be relatively insensitive to pH. The disclosed process can effectively fix the target materials, particularly arsenic, antimony and / or bismuth, of the electrolytic streams over a wide range of pH levels, as well as at extremely high and low pH values. In contrast to many conventional objective material removal technologies, the ability of the present invention to treat electrolytic currents over a wide range of pH values can eliminate the need to alter and / or maintain the pH of the solution within a narrow range. when objective material is removed. On the other hand, where the electrolytic current is a copper electrorefining current, the current can be flexibly treated without a significant problem for the pH of the electrolytic current. Still further, significant cost advantages can be achieved by eliminating the need to adjust and maintain the pH while fixing the target materials contained within the electrolytic current. The process of removing target material can also be relatively insensitive to the concentration of the target material. The process can remove relatively low and / or high levels of target material, particularly arsenic, antimony and bismuth from electrolytic streams. The process can be a robust and / or versatile process.
These and other advantages will be apparent from the description of the invention (s) contained herein.
As used herein, the term "a" or "one" refers to one or more of that entity. As such, the terms ("an" or "an", "" one or more "and" at least one ") may be used interchangeably herein. It will also be noted that the terms "comprising", "including" and "having" can be used interchangeably.
As used herein, "absorption" refers to the penetration of one substance into the interior structure of another, as distinguished from adsorption.
As used herein, "adsorption" refers to the adhesion of atoms, ions, molecules, polyatomic ions and other substances of a gas or liquid to the surface of another substance, called the adsorbent. The attractive force for adsorption can be, for example, ionic strengths such as covalent or electrostatic forces, such as van der Waals and / or London forces.
As used herein, "at least one" "one or more" and "and / or" are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B and C", "at least one of A, B or C", "one or more of A, B and C", "one or more A, B or C "and" A, B and / or C "means A alone, 'B alone, C alone, A and B jointly, A and C jointly, B and C jointly or A, B and C jointly.
As used herein, a "composition" refers to one or more chemical units composed of one or more atoms, such as a molecule, polyatomic ion, chemical compound, coordination complex, coordination compound, and the like. As will be appreciated, a composition can be held together by several types of bonds and / or forces, such as covalent bonds, metal bonds, coordination bonds, ionic bonds, hydrogen bonds, electrostatic forces (for example, van der Waals forces and forces). of London), and the like.
As used herein, "insoluole" refers to materials that are proposed to be and / or remain as solids in water and to be capable of being retained in a device, such as a column, or to be easily recovered from a reaction of lots using physical means, such as filtration. Insoluble materials must be capable of prolonged exposure to water, for weeks or months, with little (< 5%) mass loss.
As used herein, "oxyanion" or oxoanion is a chemical compound with the generic formula AxOyz "(where A represents a chemical element different from oxygen and O represents an oxygen atom.) In oxyanions containing target material," A "represents metal, metalloid and / or Se atoms (which is a non-metal.) Examples for metal-based oxyanions include chromate, tungstate, molybdate, aluminates, zirconate, bismuth, etc. Examples of metalloid-based oxyanions include ars.eniato , arsenite, antimonate, germanate, bismuth, silicate, etc.
As used herein, "particle" refers to a microencapsulated solid or liquid having a size ranging from less than one miera to greater than 100 micras, without limitation in form.
As used herein, "precipitation" refers not only to the removal of the ions containing target material in the form of insoluble species but also the immobilization of ions containing contaminant on or in insoluble particles. For example, "precipitation" includes processes, such as adsorption and absorption.
As used herein, "rare earth" refers to one or more of yttrium, scandium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium erbium, thulium, ytterbium, and lutetium. As will be appreciated, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium erbium, thulium, ytterbium and lutetium are known as lanthanoids.
As used herein, "soluble" refers to materials that readily dissolve in water. For purposes of this invention, it is anticipated that the dissolution of a soluble compound would necessarily occur on a time scale of minutes before days. For the compound to be considered to be soluble, it is necessary that it has a product of high solubility significantly such that up to 5 g / L of the compound will be stable in solution.
As used herein, "sorption" refers to adsorption and / or absorption.
The foregoing is a simplified summary of the invention to provide an understanding of some aspects of the invention. This summary is not an extensive or exhaustive review of the invention and its various modalities. It is not proposed either to identify key or critical elements of the invention nor to delineate the scope of the invention if not to present the selected concept of the invention in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth in the foregoing or described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGSThe accompanying drawings are incorporated herein and form a part of the specification to illustrate several examples of the present invention (s). These drawings, together with the description, explain the principles of the invention (s). The drawings simply illustrate preferred and alternative examples of how the invention (s) can be made and used and are not to be considered as limiting the invention (s) to only the illustrated and described examples.
Further features and advantages will become apparent from the following more detailed description of the various embodiments of the invention (s), as illustrated by the drawings referred to below.
Fig. 1 depicts a process according to an embodiment of the present invention;Fig. 2 represents an electrolysis cell according to an embodiment of the present invention; YFig. 3 represents another process according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTIONOne aspect of the present invention uses one or both of the insoluble and soluble binding agents to remove selected target materials from an electrolyte solution. Preferably, the electrolytic solution comprises an aqueous solution. The fixing agent, whether soluble or insoluble, preferably includes a rare earth. Specific examples of such materials for removing target materials include lanthanum (III) compounds, soluble lanthanum metal salts, lanthanum oxide, cerium dioxide and soluble cerium salts, which have been described in US Patent Application No. 12. / 616,653 with a filing date of November 11, 2009, the contents of which are incorporated herein in their entirety by this reference.
The electrolytic solution may be a rich electrolyte solution formed in unit operation 301 (Fig. 1) and / or an electrolyte electrolyte solution formed in an electrolysis cell 303. The rich electrolyte solution is substantially impregnated with a valuable metal to be electroplated on an electrode of the electrolysis cell 303. The electrolyzed electrolyte solution can be one of a substantially depleted electrolyte solution of the valuable metal (which was electrodeposited on an electrode, such as in an electroextraction process) or substantially loaded with contaminants generated within the electrolysis cell (such as in an electrorefining process).
The unit operation comprises the formation of an electrolyte solution rich in the valuable metal to be electrodeposited on an electrode in the electrolysis cell 303. While it is not desired to be limited for example, the unit operation 301 may comprise one or more of leaching in resin, leaching in carbon, pulp in resin, pulp in carbon, separation, leaching, ion exchange, hydrometallurgy and combinations thereof. The electrolyte solution can be formed in the leaching process, such as, an acid leach, bioleaching, pressure oxidation leaching, or other leaching process known to one of ordinary skill in the art. In addition, the leaching process can include a source of resin or carbon to concentrate and / or capture the valuable metal during the leaching process, including pulp leaching processes. The electrolytic solution can be formed in an ion exchange process, where the valuable metal is captured and / or concentrated in an ion exchange resin, followed by elution to form a concentrated solution containing valuable metal. The electrolyte solution can be formed by a separation and / or extraction process, such as, with a complexing and / or phase transfer agent to selectively extract and concentrate the valuable metal in the solution.
An objective material contained with the electrolyte solution is removed by contacting the electrolyte solution with a binding agent containing rare earth to form an insoluble binding agent loaded with target material (process 302). The objective material contained with the electrolytic solution may be one or both of the unit operation 301 or the electrolysis cell 303. Preferably, at least most, if not all, of the target material is removed from the electrolytic solution. by contacting the electrolyte solution with the fixing agent containing rare earth. The insoluble fixing agent charged with target material is separated from at least one of the rich feed stream and the electrolyzed stream to form a purified stream. The purified stream forms at least some of the electrolyte solution comprising the electrolytic cell 303.
In one embodiment, the process 302 may further include the separation of the target material from the insoluble binding agent loaded with target material to form a product of. Target material 304.
The particular target materials removed depend on whether the binding agent is insoluble or soluble in the aqueous solution, particularly under standard conditions (e.g., Temperature and Standard Pressure "). While it is not desired to be limited by any theory, it is believed , that using arsenic and cerium as an example, that insoluble cerium fixing agents effectively remove arsenic, when arsenic is part of a complex multiatomic unit that has an oxidation state of preferably +3 or higher and even more than preference is an oxidation state of +3 to +5, while soluble cerium fixative agents effectively remove arsenic, when arsenic is part of a complex multiatomic unit and has an oxidation state of +5.
"Target materials", as used herein, preferably includes not only arsenic but also elements having an atomic number selected from the group consisting of atomic numbers 5, 9, 13, 14, 22 to 25, 31, 32, 33, 34, 35, 40 to 42, 44, 45, 49 to 53, 72 to 75, 77, 78, 80, 81, 82, 83, 85, 92, 94, 95 and 96 and more preferably of the group that It consists of atomic numbers 13, 14, 33, 34, 40 to 42, 44, 45, 50, 51, 52, 77, 78, 80, 81, 82, 83, 92, 94, 95, and 96. These atomic numbers include -the elements of arsenic, aluminum, astatine, bromine, boron, fluorine, iodine, silicon, titanium, vanadium, chromium, manganese, gallium, thallium, germanium, selenium, mercury, zirconium, niobium, molybdenum, ruthenium, rhodium, indium , tin, antimony, tellurium, hafnium, tantalum, tungsten, rhenium, iridium, platinum, lead, uranium, plutonium, americium, curium and bismuth. Examples of target materials available for removal and stabilization by the insoluble fixing agent include, without limitation, objective materials in the form of complex anions, such as metal, metalloid and selenium oxyanions.
In a preferred embodiment, the removed target material comprises one of tellurium, selenium, lead, bismuth, antimony, tin, arsenic, platinum, iridium, ruthenium and rhodium. In a more preferred embodiment, the removed target material comprises one of tellurium, selenium, lead, tin, antimony, bismuth and arsenic.
In one configuration, the binding agent reacts with the target material contained in the electrolyte solution to form a purified electrolytic solution. Preferably, the target material comprises an oxyanion. In some cases, the binding agent may comprise a mixture of binding agents, the mixture comprising soluble or insoluble binding agents. The binding agent reacts with the target material to form an insoluble species with the binding agent. The insoluble species is immobilized, for example, by precipitation, to thereby produce a treated and substantially purified electrolytic solution.
The electrolytic solution further comprises an aqueous solution of the dissolved cations of the valuable metal, which are subjected to electrorefining. On the other hand, the electrolytic solution comprises a conjugate base of mineral acid, such as, but not limited to sulfate (S042_), hydrogen sulfate (HS041_), nitrate (N031_), chloride (Cl1_) and bromide (Br1") In some embodiments, the electrolyte may comprise a sulfamate solution, such as, in some configurations for nickel electrorefining.
Fig. 2 represents an electrolysis cell 100 for the electrorefining of a valuable metal. The electrolysis cell 100 comprises an anode 10, a cathode 104, an electrolytic solution 106, an external current path 108 and an energy source 110. In the electrorefining process, the anode 102 comprises a valuable metal containing contaminant. The cathode 104 preferably comprises one of a valuable metal substantially free of a contaminant or a metal substantially unreactive with the valuable metal in which the valuable metal is electrodeposited. The external current path 108 comprises an electrically conductive path, such as a wire typically used within an electrical circuit. The power source 110 is any electrical power source, such as an electrical generator, a power substation, or a battery.
The electrolytic solution 106 comprises an electrolyte solution, preferably an aqueous electrolyte solution. An electrolyte solution means a solution comprising a solvent (such as water) and ionically dissociated components, wherein the ionically dissociated components comprise cations and anions that conditional on electricity and can be separated from the solution by an electrically charged electrode. The electrolytic solution 106 comprises the valuable metal in a dissolved state as a cation, such as Mn +, where n is an integer greater than zero. The electrolyte solution 106 preferably also comprises a mineral acid or the conjugate base of a mineral acid. Preferred mineral acids include, without limitation, hydrochloric, hydrobromic, sulfuric acid. Preferably, the mineral acid comprises sulfuric acid (H2SO4) and / or the conjugated bases of sulfuric acid (HS041_ and / or S042").
In the electrorefining process, the anode 102 has a positive charge (that is, the anode accepts electrons in an oxidizing process) and the cathode 104 has a negative charge (that is, the cathode releases electrons in a reducing process). The electrochemical process at the anode 102 comprises dissolving the valuable metal at the anode 102. That is, the electrons are removed and / or taken away from the anode 102 by an energy source 110 and the valuable metal species and contaminants are generated . Electrochemical reactions of the anode 102 can be expressed by the following chemical reactions:M ° - > n + + n e "(3)K ° - > Km + + m e "(4)where M represents the valuable metal, K represents the one or more contaminants contained within the anode 102, and n and m are integers greater than zero.
The oxidized species Mn + and Km + are dissolved in the electrolytic solution 106 as soluble components of the electrolytic solution 106. The oxidized Km + species comprises contaminants that have substantially electrochemical oxidation potentials (ie, for electrochemical potentials for the 100 electrolysis cell given) approximately equal or more reactive (that is, less noble) than the valuable metal.
In some configurations, the oxidized contaminant K is in the form of an oxyanion. The oxyanion | comprises KxOyz ~ (where K represents a chemical element different from oxygen and 0 represents an oxygen atom).
The noblest pollutants, that is, they have a greater potential for electrochemical oxidation than the valuable metal, form few, if any, dissolved cationic species. The noblest contaminants form a solid, substantially insoluble lamella 112 within the electrolysis cells 110. The lamella 112 comprises one or more precious metal contaminants.
Under an electric potential applied by the power source 110, the electrons flow from the anode 102 to the cathode 104 through the external current path 108 and the power source 110 and the flow of cationic species (Mn + and Km +) of the anode 102 to the cathode 104 through the electrolytic solution 106 to complete the electrical circuit. On the other hand, the anions comprising the electrolytic solution 106 within the electrolysis cell 100 flow from the cathode 104 to the anode 102. One or both of the cationic species are deposited at the cathode 106. When the oxidized contaminant K- is in the In the form of oxyanion, the oxyanion flows to the anode 102 under the applied electrical potential. The electrochemical reactions of the cathode 104 can be expressed by the following chemical reactions:Mn + + n e "-> M ° (5)Km + + m e "-> K ° (6)At the cathode 104 one or both of the valuable metal cation Mn + and the one or more contaminating cations Km +, respectively, accept n and m electrons and are electrodeposited at the cathode 104 as reduced species, preferably M ° and K °. At least most of the valuable metal M is deposited at the cathode 104 and little, if any, of one or more contaminants K is deposited at the cathode 104. The ability and / or degree that the valuable metal cation Mn + and the one or more Km + polluting cations deposited respectively on the cathode are influenced by the reducing potentials for the valuable metal and the one or more pollutants in the electrolytic solution 106 and the conditions under which the 100 electrolysis cell is operated. The valuable metal it can be any metal. Preferably, the valuable metal is a transition metal in a more preferred embodiment, the valuable metal is one copper, nickel or cobalt.
In copper electrorefining, the anode 102 comprises copper. Preferably, the copper anode has a copper purity level of at least about 95%. More preferably, the copper purity level of the anode 102 is at least about 99%, more preferably at least about 99.9%.
The copper anode further comprises one or more contaminants. , The one or more pollutants include arsenic, antimony, bismuth, nickel, cobalt, tin, zinc, iron, tellurium, selenium, lead, silver, gold and metals of the platinum group. The metals of the platinum group are platinum, osmium, iridium, ruthenium, rhodium and palladium. Slat 112 comprises the one or more nobler contaminants than copper such as silver, gold, osmium, iridium, ruthenium, rhodium, palladium, nickel, lead (typically as insoluble lead sulfate) and mixtures thereof which are non-exemplary examples. limitations. The one or more contaminants that have an oxidation potential approximately equal to and / or less noble than copper include arsenic, antimony, bismuth, nickel, iron, cobalt, tin, zinc, tellurium, selenium, and lead.
The electrolytic solution 106 preferably comprises an aqueous copper solution. More preferably, the electrolytic solution 106 comprises copper sulfate, more specifically, copper (II) sulfate. The electrolytic solution 106 has a copper sulfate concentration of about 20 to about 300 grams of copper sulfate per liter. Preferably, the copper sulfate concentration of the electrolyte solution is from about 100 to about 200 grams of copper sulfate per liter. More preferably, the copper sulfate concentration of the electrolytic solution 106 is from about 30 grams / liter to about 60 grams / liter. The electrolytic solution 106 further comprises sulfuric acid. Preferably, the sulfuric acid of the electrolytic solution 106 has a concentration of about 100 to about 500 grams of H2SO4 per liter, more preferably of about 150 to about 250 grams of H2SO4 per liter.
In addition, the electrolyte solution 106 comprises one or more contaminants. The one or more pollutants comprise arsenic, tin, zinc, antimony, bismuth, nickel, iron, cobalt, tellurium, selenium and lead. Lead and nickel may be present in the electrorefining cell in one or both of the electrolyte solution 106 as a cationic species (that is, Pb2 + and Ni2 +) and lama 112 (as insoluble lead sulfate and as nickel metal). In electrolytic solutions comprising sulfate, Pb2 + is more cationic, it is typically low due to the formation of a precipitate of PbSC >4 substantially insoluble. Iron and cobalt are substantially present within the electrolytic solution 106 as cationic species, that is, respectively, as one or more of Fe2 +, Fe3 +, Co2 + and Co3 +. Preferably, the cobalt and nickel comprising the electrolytic solution has an oxidation state of +2. Arsenic, antimony, bismuth, tellurium and selenium are preferably present in the electrolytic solution 106 as ionic species. That is, arsenic is preferably present in the electrolyte solution 106 as one or both of arsenite, AsO ^ ", and arsenate, As043 ~, oxyanions, preferably at least the majority of arsenic is present as an arsenate. Preferably, at least about 95% of the arsenic comprising the electrolytic solution 106 comprises arsenate.In addition, the antimony comprising the electrolytic solution 106 may comprise one or more axianions Sb (OH) 41-, Sb021", Sb (OH) 61_ and Sb031_. Preferably, the antimony comprises antimony having one of an oxidation state of +5 or +3. The electrolytic solution 106 may comprise one or more of the following bismuth ionic species Bi (H20) 63+, Bi (H20) 5 (OH) 2+, Bi (H20) 4 (OH) 21+, Bi (H20) 3 (OH) 3, Bi (H20) 2 (OH) 41_, Bi031_, Bi021_, Bi033 ~ and Bi01 +. Preferably, the bismuth comprises bismuth having one of an oxidation state of +5 or +3. The electrolyte solution may comprise one or more of the following tellurium and selenium species: Te02 ~, Te042 ~, Te066", Se042 ~ and Se032". In some modalities, the solutionElectrolytic 106 comprises silver having an oxidation state of +1.
The one or more contaminants dissolved in the electrolyte solution 106 increases in concentration as the copper dissolves in the electrolyte 106 which is electrodeposited on the cathode 104 and as additional copper and contaminants dissolved in the anode 102. As the concentration of the contaminants is increased, the electrodeposition of the contaminants in the cathode 104 can be substantially increased. In addition, as the level of the contaminants in the electrolyte solution 106 increases, the contaminants can destabilize the electrolyte solution 106. For example, high levels of arsenic within the electrolyte solution can form precipitates and / or complex ionic species with other contaminants within the electrolyte solution 106 (such as, but not limited to antimony, bismuth, selenium and tellurium). Contaminants having a reduction potential, in their concentration in electrolyte solution 106, approximately equal to or less noble than copper can be electrodeposited with copper at cathode 104. Electrodeposition of at least some of the contaminants at the cathode 104 can affect the quality and purity of the electrodeposited copper. For example, contaminants can affect the grain structure of electrodeposited copper.
The concentration of the contaminants can vary in the electrolyte solution 106. While it is not desired to be limited for example, the nickel concentration can be as large as about 150 g / L or larger. Preferably, the concentration of nickel in the electrolyte solution 106 is from about 0 g / L to about 40 g / L. more preferably, the nickel concentration of the electrolyte solution 106 is from about 0 g / L to about 20 g / L. the concentration of arsenic in the electrolyte solution 106 can be as large, approximately 60 g / L or larger. Preferably, the concentration of arsenic in the electrolyte solution 106 is from about 0.1 g / L to about 25 g / L. more preferably, the electrolyte arsenic concentration 106 is from about 1 g / L to about 25 g / L. the concentration of iron in the electrolyte solution 106 can be as large as about 25 g / L or larger. Preferably, the concentration of iron in the electrolyte solution 106 is from about 0.1 g / L to about 15 g / L. more preferably, the concentration of electrolyte iron is from about 3 g / L to about 5 g / L. the antimony concentration of the electrolyte solution can be as large as 2 g / L or larger. Preferably, the concentration of antimony in the electrolyte solution 106 is from about 0.1 g / L to about 1.5 g / L. More preferably, the electrolyte antimony concentration is from about 0.8 g / L to about 1.0 g / L. The bismuth concentration of the electrolyte solution can be as large as about 1.5 g / L or larger. Preferably, the concentration of bismuth in the electrolyte solution 106 is from about 0.05 g / L to about 0.7 g / L. More of. Preferably, the bismuth concentration of the electrolyte solution is from about 0.1 g / L to about 0.5 g / L. further, the electrolytic solution 106 may comprise one or more of: cobalt having the solution concentration from about 0 g / L to about 3 g / L; tin having a solution concentration of about 0 g / L to about 1 g / L; zinc having a solution concentration of about 0 g / L to about 1 g / L; tellurium having a solution concentration of about 0 mg / L to about 10 mg / L; and selenium having a solution concentration of about 0 mg / L to about 10 mg / L.
In copper electrorefining, at least the majority of the electrodeposited cathode 104 comprises copper. The electrodeposited cathode 104 comprises at least about 99% copper. Preferably, at least about 99.9% of the electrodeposited cathode 104. comprises copper. More preferably, the electrodeposited cathode 104 comprises at least about 99.99% copper. Even more preferably, at least about 99.999% of the electrodeposited cathode 104 comprises copper.
Fig. 3 depicts a process 200 for treating electrolyte solution 106 having a target material and a valuable metal. The target material may comprise waste materials and / or valuable recoverable materials.
In step 120, a side stream 125 of the electrolyte solution 106 is removed from the electrolysis cell 100. The side stream 125 may be a side stream substantially continuously generated, such as a purge stream, or it may be a intermediate stream removed in the form of a batch volume lateral stream. It can be seen that the lateral stream 125 contains objective material contained within the electrolytic solution 106. The lateral stream 125 comprises a volume percent of the total volume of electrolytic solution 106, the volume percent of the side stream 125 is represented by the following formula:% by volume of the side stream = 100 * volume of the side stream / total volume of the electrolyte solution in the process (7)Preferably, the volume percent of the lateral stream 125 is no| greater than about 25% of the total volume of the electrolyte solution 106. More preferably, the volume percent of the sidestream 125 is no larger that approximately 3%. Even more preferably, the volume percent of side stream 125 is no larger than about 1% of total electrolyte solution 106. In some configurations, the volume percent of side stream 125 is about 0.001. % to about 0.1% of the total electrolyte solution 106. It can be seen that the volume of side stream 125 may vary depending on one or more of the level of contaminants contained within the anode, the level of contaminants dissolved in the solution electrolyte 106 and the desired level of contaminants that can be adequately maintained within electrolyte solutions 106.
In step 130, the side stream 125 is contacted with a fixing agent. The fixing agent can be a soluble or insoluble fixing agent. While it is not desired to be limited by any theory, it is believed that soluble and insoluble rare earth fixing agents do not commonly remove the metal and cations of metalloid dissociates from the solution. This may allow metal and metalloid oxyanions to be selectively removed from a solution containing both metal and metalloid oxyanions and dissociated cations.
In a preferred embodiment, the side stream 125 is contacted with the insoluble fixing agent to form an insoluble binding agent loaded with target material and a purified side stream 195. The sidestream 125 has an initial concentration of the target material within sidestream 125. The fixative agent may comprise an adsorbent or absorbent. The contact of the fixing agent with the lateral stream 125 having target material within the side stream 125 removes most, if not all, of the objective material from the sidestream 125 to form the purified side stream 195. The side stream Purified 195 has a purified concentration of the target material contained within the purified side stream 195. The initial concentration is at least no greater than the purified concentration. Preferably, most, more preferably about 75% or more, and even more preferably about 95% or more of the target material in side stream 125 is loaded onto the insoluble fixing agent.
Preferably, the purified side stream 195 has an arsenic concentration of less than about 15 g / 1 of dissolved arsenic, more preferably less than about 10 g / L of dissolved arsenic. Even more preferably, the concentration of arsenic in the purified sidestream is less than about 1 g / L. The concentration of antimony dissolved in the purified side stream 195 is preferably less than about 300 mg / L, more preferably less than about 200 mg / L. Even more preferably, the purified side stream 195 has a concentration of dissolved antimony less than about 100 mg / L. The concentration of bismuth dissolved in the purified side stream 195 is preferably less than about 300 mg / L, more preferably less than about 200 mg / L. Even more preferably, the purified sidestream 195 has a dissolved bismuth concentration less than about 100 mg / L. Preferably, the purified side stream 195 has a tellurium concentration of less than about 1 mg / 1 dissolved tellurium, more preferably less than about 0.5 mg / L dissolved tellurium. Even more preferably, the tellurium concentration dissolved in the purified sidestream is less than about 0.1 mg / L. Preferably, the purified sidestream 195 has a selenium concentration of less than about 1 mg / 1. of dissolved selenium, more preferably less than about 0.5 mg / L of dissolved selenium. Still More preferably, the concentration of selenium dissolved in the purified side stream is less than about 0.1 mg / L.
In a preferred embodiment, the insoluble fixing agent comprises one of yttrium, scandium and lanthanoid. The insoluble binding agent is preferably a particulate solid. The insoluble fixing agent is preferably an insoluble rare earth compound comprising an insoluble earth oxide, such as rare earth oxides and treated or anhydrous, or a fluoride, carbonate, fluorocarbonate, rare earth silicate and the like. The insoluble binding agent is particularly effective in removing arsenic that has an oxidation state of +3 or +5. In a more preferred embodiment, the insoluble de-binding agent comprises cerium. In a more preferred embodiment, the insoluble fixing agent comprises cerium oxide. A particularly preferred insoluble fixing agent is Ce02. The insoluble fixing agent is preferably a finely divided solid having an average surface area of between about 25 m2 / g and about 500 m2 / g, more preferably between about 70 m2 / g and about 400 mVg and even more preferably between approximately 90 m2 / g and approximately 300 m2 / g.
The insoluble fixing agent can be derived from the precipitation of a rare earth metal salt or from the thermal decomposition of, for example, a carbonate and rare earth metal oxalate at a temperature preferably between about 100 to about 700 and even more preferably between about 180 and 350 ° C in an oven in the presence of an oxidant, such as air. The formation of the insoluble fixing agent is further discussed in co-pending US Application Serial No. 11 / 932,837, filed on October 31, 2007, which is incorporated herein by this reference.
Although the preferred insoluble fixing agent comprises a rare earth compound, other fixing agents can be employed. Any fixing agent, whether solid, liquid, gaseous or gel, which is effective to fix in objective material in solution through precipitation, ion exchange or some other mechanisms can be used. Examples of other fixing agents include at least those set forth in the foregoing.
In one configuration, the insoluble fixing agent is an aggregate particulate material having an average surface area of at least about 1 m2 / g. Depending on the application, higher surface areas may be desired. For example, aggregated particulate materials may have a surface area of at least about 5 m2 / g; in other cases, more than approximately 10 m2 / g; and, in still other cases, more than approximately 25 m2 / g. Where higher surface areas are desired, the particulate materials may have a surface area of more than about 70 m2 / g; in other cases, more than approximately 85 m2 / g; in still other cases, more than approximately 115 m2 / g; and, in still other cases, more than approximately 160 m2 / g. The aggregated particulate materials may include a polymeric binder, such as thermosetting polymers, thermoplastic polymers, elastomeric polymers, cellulosic polymers and glasses, to at least one of binding, fixing and / or attracting the constituents of the insoluble fixing agent in the particulate materials. which have one or more of desired size, structure, density, porosity and fluid properties.
The insoluble fixing agent can include one or more flow aids, with or without a binder. Flow aids can improve the fluid dynamics of a fluid on and / or through the insoluble fixing agent to prevent separation of suspension components, prevent settling of fines and, in some cases, contain fixing agents and other components in the right place.
The insoluble fixing agents can be mixed with or include other components, such as ion exchange materials (e.g., synthetic ion exchange resins), porous carbon such as activated carbon such as metal oxides (e.g., alumina, silica, silica) -alumina, gamma-alumina, activated alumina, acidified alumina and titania), metal oxides containing unstable metal anions (such as aluminum oxychloride), non-oxide refractories (e.g., titanium nitride, silicon nitride and silicon carbide) silicon), land of atonasia, mulita, porous polymeric materials, crystalline aluminosilicates such as zeolites (synthetic occurring naturally), silica-alumina amorphous, minerals and clays (bentonite, smectite, kaolin, dolomite, montmorilinite and its derivatives), resins of ion exchange, porous and mineral ceramic metal silicate materials (for example, one of the three phosphate and oxide), salts fabrics and fibrous materials (including synthetic (for example, without limitation, polyolefins, polyesters, polyamides, polyacrylates and combinations thereof) and natural (such as, without limitation, plant-based fibers, animal-based fibers, organic-based fibers) , cellulose, cotton, paper, glass and combinations thereof).
The insoluble fixing agent loaded with target material comprises most of the target material in side stream 125. The insoluble fixing agent and the target material form a fixing agent loaded with substantially insoluble target material. Preferably, the majority, and still more preferably about 75% or more, of the target material is loaded onto the insoluble fixing agent. The affinity of the insoluble binding agent for specific target materials is believed to be a function of the pH and / or or the concentration of target material. The insoluble fixing agent is commonly used with a particulate material in a fixed or fluidized bed and, in certain configurations, may be desirable for use in a stirred tank reactor. In one configuration, the insoluble binding agent includes a flocculent and / or dispersing agent, as discussed herein, to maintain a substantially uniform particle distribution in the bed.
In some embodiments, the target material will be present in a reduced oxidation state, and this condition could be undesirable. In such cases, an oxidant may be contacted with side stream 125 to increase the oxidation state of the target material. That is, the contact step 130 can be preceded by an oxidation step to assist the target material for better removal efficiency of the target material and / or affinity of the target material for the insoluble fixing agent. Using arsenic as an example, the presence of arsenite could favor the use of an oxidant before the fixing agent is applied.
The operational conditions of process 200 must be controlled. When arsenic is the target material, for example, the insoluble binding agent, under appropriate process conditions, selectively removes at least the majority of the arsenic while leaving at least the most valuable product as dissolved species (cationic) in the current of lateral 125. Although the insoluble fixing agent can effectively fix the arsenic of. solutions over a wide range of pH levels, the pH of side stream 125 is preferably no more than about pH 6 and even more preferably is no more than about pH 2 to adsorb both arsenic (V) and arsenic (III). The arsenic (III) is sorbed on the insoluble binding agent over a wide pH range while the arsenic (V) is preferably sorbed by the insoluble binding agent at lower pH levels.
In step 140, the purified side stream 195 is separated from the insoluble binding agent charged with target material. The separation process may be any method known to one of skill in the art for separating a liquid stream from a solid, such as, but not limited to, centrifugation, cyclonic (including hydrocyclone), decantation (including decanting to countercurrent), filtration (including screening), sedimentation (including gravity separation techniques) and combinations and / or variations thereof.
In one configuration, the insoluble binding agent can be supported and / or configured so that sidestream 125 flows through the insoluble binding agent. The insoluble fixing agent loaded with target material is formed on the support and / or is configured for the purified sidestream 195 to flow through the insoluble fixing agent.
When a preselected degree of loading of target material sorbs the fixing agent occurs, the fixing agent loaded with target material is contacted, in step 150, with a separation solution, or release agent, to discharge, or dissolve , preferably most and still more preferably about 95% or more of the target material of the fixing agent loaded with target material and forming. a sterile fixing agent 160 (which is recycled in step 130) and one or both of a separate product 185 and a valuable product 175.
Any solution of acidic, neutral or basic separation or release agent can be used. The process of desorption of the binding agent loaded with target material is believed to be a result of one or more of: 1) a stronger affinity for the rare earth comprising the binding agent for the release agent than the target material sorbed or its composition and 2) an upward or downward adjustment of the oxidation state of the rare earth comprising the surface of the fixing people and / or the target material sorbed and / or the oxyanion containing sorbent target material.
In one application, the separation solution is alkaline and comprises a strong base. Preferably, the separation solution comprises at least one of an alkali metal hydroxide and group I salt of ammonia, an amide and an amine (such as a primary, secondary, tertiary or quaternary amine) and mixtures thereof. . More preferably, the separation solution comprises an alkali metal hydroxide. While not wishing to be limited by any theory, it is believed that, at high concentrations, the hydroxide ions compete with, and displace, two oxyanions from the surface of the insoluble fixing agent. In one formulation, the separation solution includes a caustic compound in an amount that preferably ranges from about 1 to about 15% by weight, even more preferably from about 1 to about 10% by weight, and even more preferably from about 2.5 to about 7.5% by weight, with about 5% by weight which is even more preferred.
The preferred pH of the separation solution is preferably larger (eg, more basic) than the pH at which the target material was loaded onto the fixing agent. The pH of the separation solution is preferably at least about pH 10, still more preferably at least about pH 12, and even more preferably at least about pH 14.
In another application, the (first) separation solution comprises an oxalate or ethanedioate, which, relative to the oxyanions containing target material, is preferably sorbed, over a wide range of pH, by the insoluble fixing agent. In a variation of the process for desorbing oxalate, the insoluble fixing agent is contacted with a second separation solution having a preferred pH of at least about pH 9 and even more preferably at least about pH 11. to desorb the oxalate and / or ethanedioate ions in favor of hydroxide ions. A strong base is preferred for the second separation solution. Alternatively, the oxalate and / or ethanedioate sorbed anions can be set at a preferred temperature of at least about 500 degrees Celsius to thermally decompose the sorbed oxalate and / or ethanedioate ions and remove them from the insoluble fixing agent.
In another application, the (first) separation solution includes a strongly adsorbent exchange oxyanion, such as phosphate, carbonate, silicate, vanadium oxide or fluoride, to desorb the oxyanion containing the sorbed target material. The first separation solution has a relatively high concentration of exchange oxyanion. The desorption of the exchange oxyanion is done at a different (higher) pH and / or the exchange oxyanion concentration, than the first separation solution. For example, desorption may be by a second separation solution that includes a strong base and has a lower concentration of exchange oxyanion than the concentration of oxyanion in the first separation solution. Alternatively, the exchange oxyanion can be thermally decomposed to regenerate the insoluble binding agent. Alternatively, the exchange oxyanion can be desorbed by oxidation or reduction of the insoluble binding agent or exchange oxyanion.
In another application, the separation solution includes a reductant or reducing agent, such. such as ferrous ion, lithium aluminum hydride, nascent hydrogen, sodium amalgam, sodium bromide, stannous ion, sulphite compounds, hydrazine (Wolff-Kishner reduction), zinc-mercury amalgam, diisobutylaluminum hydride, boundary catalyst , oxalic acid, formic acid and a carboxylic acid (for example, a sugar acid, such as ascorbic acid) to reduce the target material sorbed in the rare earth and / or the oxyanion containing the sorbed target material. While not wishing to be limited in any theory or by way of example, the surface reduction of the insoluble fixing agent will reduce the cerium (IV) to cerium (III), which may interact less strongly with the target materials and oxyanions. Subsequently, with the surface reduction of the insoluble fixing agent, the pH is increased to desorb the target material sorbed to its anion.
In another application, the separation solution includes an oxidant or oxidizing agent, for example peroxygen compounds (eg, peroxide, permanganate, persulfate, etc.), ozone, chlorine, hypochlorite, Fenton reagent, molecular oxygen, phosphate, dioxide of sulfur and the like, which oxidizes the target material sorbed and / or its oxyanion to a higher oxidation state, for example, arsenic (III) to arsenic (V); followed by a pH adjustment and a desorption process. Desorption of arsenic (V) from insoluble earth compounds, for example, typically occurs at a pH of at least about pH 12 and even more typically at least about pH 14.
Regardless of the precise separation mechanism, a first concentration of the target material in sidestream 125 is typically less than a second concentration of the target material in one or both of the separate product 185 and the valuable product 175. Commonly, the first concentration of the material target is no more than about 75% of the second concentration and still more commonly no more than about 50% of the second concentration. By way of example, a first concentration of arsenic is between about 0.1 mg / L to about 5 g / L, and the second concentration of arsenic is between about 0.25 g / L and about 7.5 g / L.
Optionally (not shown), the target material is removed from one or both of the separate product 185 and the valuable product 175 by a suitable technique to form a target material and a sterile separation solution (which can be recycled in step 150). The removal can be done by any suitable technique including precipitation (such as the use of a sulfide (for transition metals), an alkaline earth metal carbonate (for fluoride) and a rare earth or iron salt (for arsenic)) , adsorption, absorption, electrolysis, cementation, amalgamation and the like. In one configuration, the target material is precipitated using a soluble rare earth binding agent as mentioned above.
Preferably, the second concentration of the target material is approximately equal to the solubility limit (concentrations) of the target material (under the conditions of the process). More preferably, the second concentration of the target material is between about 0.1 and about 2,500 g / L, even more commonly between about 0.1 and about 1,000 g / L and even more commonly between about 0.25 g / L and about 500 g / L. Finally, a second soluble or dissolved fixing agent is contacted with one or both of the separated product 185 and the valuable product 175 in an amount sufficient to precipitate most, if not all, of the target material as a solid carrying material objective. The solid carrying target material can be separated from the intermediate solution by any suitable solid / liquid separation technique to produce a separation solution for recycling and a separate solid for disposal or recovering a valuable solid (not shown).
The valuable product 175 and the valuable solid can be any metal of interest. Non-limiting examples of metals of interest include, without limitation, one or more of the transition metals. Preferably, the metals of interest include a metal selected from the group of metals consisting of copper, nickel, cobalt, lead, precious metals and mixtures thereof. All or a portion of the valuable product of side stream 125 can be recovered.
The second insoluble binding agent typically has a lower oxidation state than the oxidation state of the first binding agent. Preferably, the oxidation state of the second fixing agent is one of +3 or +4. The soluble fixing agent is preferably a soluble rare earth metal compound and more preferably includes salts comprising rare earth compounds. Such as bromides, nitrates, phosphites, chlorides, chlorites, chlorates, nitrates and the like. More preferably, the insoluble fixing agent is a rare earth chloride (III).
Although not shown, the concentration of the target material in the side stream 125 can be increased by any suitable technique, such as through the removal of water. The water can be removed, for example, by evaporation, distillation and / or filtration techniques (such as membrane filtration). Other techniques include precipitation and redissolution, absorption or adsorption followed by separation, ion exchange followed by separation and the like from the target material.
In step 190 the separate purified side stream 195 is recycled to the electrolysis cell 100. The purified side stream 195 has, relative to the side stream 125, a reduced concentration of the target material. In one application, the purified stream 195 preferably is not more than about 1,000 ppm, even more preferably not more than about 500 ppm, even more preferably not more than about 50 ppm, and still more preferably not more than about 1 ppm of the target material. In some configurations, the purified stream 195 is no more than about 50 ppb, even more preferably no more than about 5 ppb of the target material.
In another embodiment where the binding agent comprises a soluble binding agent, the insoluble binding agent is contacted with sidestream 125 to form a composition containing insoluble target material and a purified side stream 195. The target material comprises the one or more contaminants contained within side stream 125. Preferably, the insoluble fixing agent comprises a rare earth. More preferably, the insoluble fixing agent comprises a composition containing rare earth having one or more rare earths.
The composition containing insoluble target material comprises the composition containing rare earth having one or more rare earths. The composition containing insoluble target material is typically in the form of a precipitate that can be removed as a solid. Preferably, the composition containing, insoluble target material is at least about 0.01% by weight, even more preferably at least about 0.1% by weight and even more preferably ranges from about 5 to about 50% by weight of the target material .
The soluble binding agent, or precipitant, can be supported by a suitable carrier or can be unsupported. The ability to form the composition containing insoluble target material in the form of a solid comprising a relatively high concentration of the target material can greatly reduce the volume of the composition containing insoluble target material requiring disposal, thereby reducing waste costs .
Preferably, most and even more preferably about 75% or more of the target material? A composition incorporating the target material is combined, with the insoluble fixing agent to form the composition containing insoluble target material. The insoluble fixing agent is preferably one or more of scandium, yttrium and a lanthanoid and is in a form that is soluble in water and / or sidestream 125. When the soluble fixing agent comprises cerium, the cerium preferably has an oxidation state of +4 or less. The insoluble fixing agent can be without limitation, a salt comprising a bromide, nitrate, phosphite, chlorite chloride, chlorate and the like of scandium, yttrium or lanthanoid, with a chloride of cerium (III), cerium (IV) or a mixture of the same that is preferred. While not wishing to be limited by any theory, it is believed that the soluble forms of cerium (IV) can form nonocrystalline cerium dioxide, which then sorb the objective materials or a composition incorporating the target material. The insoluble fixing agent is added, commonly as a separate aqueous solution, side stream 125. Preferably, the insoluble fixing agent is added to side stream 125 in an amount to produce an average molar ratio of the binding agent to the material target in solution of less than about 8: 1 and preferably ranging from about 0.5: 1 to about 5: 1.
In one configuration, the pH of the sidestream is adjusted to maintain at least some, if not at least the majority, of the soluble binding agent dissolved in side stream 125. That is, the pH of the side stream. 125 is adjusted to form little, if any, sulfate, rare earth carbonate and / or hydroxide precipitate.
In another configuration, a chelating agent can be added to the aqueous solution of soluble binding agent and / or sidestream 125 to increase the solubility of the binding agent in one or both of the aqueous solution of binding agent and / or stream lateral 125. A typical chelating agent is a chemical compound that contains at least two non-metal entities capable of binding to a metal atom and / or ion. While not wishing to be limited by any theory, chelating agents work by making several chemical bonds with metal ions. Exemplary chelating agents include ethylene diamine tetra acetic acid (EDTA), dimercaprol (BAL), dimercaptosuccinic acid (DMSA), 2,3-dimercapto-1-propanesulfonic acid (DMPS) and lipoic alpha (ALA), aminophenoxyethane-tetraacetic acid ( BAPTA), deferasirox, deferiprone, deferoxamine, diethylene triamine pentaacetic acid (DTPA), dimercapto-propane sulfonate (DMPS), ethylenediamine tetraacetic acid (calcium disodium versant) (CaNa2 ~ EDTA), ethylene glycol tetraacetic acid (EGTA), D-penicillamine, methanesulfonic acid, methanophosphonic acid and mixtures thereof.
The soluble fixing agent may additionally include one or both of an organic or inorganic additive. Preferably, the additive is one or more of a flocculent, coagulant and thickener, to induce flocculation, settlement and / or formation of the precipitated solids. Examples of such additives include lime, alum, ferric chloride, ferric sulfate, ferrous sulfate, aluminum sulfate, sodium aluminate, polyaluminum chloride, aluminum trichloride, polyelectrolytes, polyacrylamides, polyacrylate and the like.
In step 140, the composition containing insoluble target material is separated from a purified side of stream 195. The composition containing insoluble target material can further be processed to form one or more of a separate product 185, valuable product 175, solid valuable and / or separate solid.
In yet another embodiment, the contact of the fixing agent with the side stream 125 comprises the formation of a precipitate between a target material and at least one of the rare earth and non-rare earth salt additives and a purified side stream. The target material comprises the one or more contaminants contained within sidestream 125.
The rare earth salt additive comprises a rare earth in the +3 oxidation state. In one formulation, the rare earth salt additive comprises a salt solution based on bimetallic lanthanide. In a preferred formulation, the non-rare earth salt additive comprises aluminum in the +3 oxidation state. In another preferred formulation, the rare earth salt additive comprises cerium in the oxidation state +3.
The non-rare earth salt additive comprises a non-rare earth metal in the +3 oxidation state and is substantially free of a rare earth. The non-rare earth metal can be any non-rare earth metal in the +3 oxidation state, with transition metals, boron, aluminum, gallium, indium and thallium being preferred, and the transition metals and aluminum which are particularly preferred. The non-rare earth salt additive particularly provides a significant reduction in the amount of rare earth needed to remove arsenic from side stream 106. Preferred transition metals include elements having atomic numbers 22-29, 40-45, 47 , 72-77 and 79. Preferred transition metals include the transition metals titanium vanadium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, silver, hafnium, tantalum, tungsten, rhenium, osmium, iridium and gold.
Preferably, the rare earth and non-rare earth salt additives combine to form a mixed salt additive. For example, the soluble binding agent (s) is combined with one or more non-rare earth having a +3 oxidation state, particularly a transition metal or metal of group 13 of the Periodic Table of the Elements, with aluminum or iron in the +3 oxidation state which is preferred. Preferably, the soluble binding agent is a rare earth metal in the +3 oxidation state, and the soluble fixing agent and the non-rare earth metal are each in the form of water-dissociable salts. For example, a double salt mixture is formed by mixing cerium (III) chloride with aluminum (III) chloride. In another example, the double salt mixture is formed by mixing lanthanum (III) chloride with aluminum (III) chloride. In another example, the double salt mixture is formed by mixing lanthanum (III) chloride with iron (III) chloride. In a preferred formulation, at least one mole of the rare non-earth is present for each mole of the rare earth soluble fixing agent. In a more preferred formulation, at least 3 moles of the rare non-earth is present for each mole of the rare earth soluble fixing agent. In a still more preferred formulation, at least one mole of the rare non-earth having an oxidation state of +3 is present for each mole of the rare earth soluble fixing agent having an oxidation state of +3. In a yet still more preferred formulation, at least 3 moles of the rare non-earth having an oxidation state of +3 are present for each mole of the rare earth soluble fixing agent having an oxidation state of +3. A solution comprising the mixed salt additive can have any pH; that is, the mixed salt solution can have an acidic, neutral or basic pH. The mixed salt additive, which is typically a solution, of salt based on bimetallic lanthanide, is contacted with the side stream 125 at standard or higher temperature. The mixed salt solution may be contacted with side stream 125 over a wide range of temperatures, preferably from about the freezing point of side stream 125 to about the boiling point of side stream 125.
The side stream 125 has a pH value. The pH value in sidestream 125, before and after the addition of the mixed salt, can vary from a pH of about pH 0 or less to a pH of about pH 14 or greater. In some configurations, the pH of sidestream 125 has a pH of less than about pH 8, before and after contacting side stream 125 with the mixed salt solution. More preferably, the pH of the side stream after contact with the mixed salt solution is less than about pH 2.
In one configuration, the contact of the rare earth and non-rare earth salt additives with the side stream 125 forms the precipitate. In another configuration, the contact of the non-rare earth salt additive with the side stream 125 forms the precipitate. In a preferred configuration, the rare earth salt additive comprises cerium in the +3 oxidation state and the non-rare earth salt additive includes aluminum in the +3 oxidation state. The non-rare earth salt additive can provide significant reductions in the amount of rare earth required to remove the one or more selected contaminants from the side stream 106.
In step 140, the purified sidestream 195 is separated from the precipitate. The precipitate can further be processed to form one or more of a separate product 185, valuable product 175, valuable solid and / or separate solid.
In still yet another embodiment, contacting the lateral stream 125 with the fixing agent further comprises providing a side stream having one or more dissolved contaminants and one or more valuable dissolved products and providing a fixing agent comprising a rare earth. Preferably, at least one or more contaminants are in the form of any oxyanion. Preferably, at least one of the one or more valuable dissolved products is a transition metal. The contact of sidestream 125 and the fixing agent precipitates at least the majority of the dissolved target material as a precipitate containing target material and leaves at least the majority of the valuable product dissolved in the purified side stream 195. In the step 140, the purified side stream 195 is separated from the precipitate containing target material. The precipitate containing target material can also be processed to form one or more of a separate product 185, valuable product 175, valuable solid and / or separate solid.
The residual soluble binding agent can be removed by precipitation or other suitable separation methods known to one skilled in the art. The residual soluble binding agent can be removed by the form of an insoluble rare earth composition within the purified side stream 195. The insoluble rare earth composition can be formed by adjusting the pH and / or adding a precipitant-forming composition to the purified side stream 195. The precipitating forming composition contains one or more entities that form a precipitate when contacted with the rare earth contained within the purified side stream 195. While not wishing to be limited for example, any composition of solubilized and / or dissolved rare earth can be removed from the purified side stream 195 by contacting an oxalate and / or carbonate, the carbonates which are preferred for the purified side streams having a pH greater than about pH 7.
In another embodiment of the present invention, the insoluble rare earth fixing agent can be added to the electrolytic solution contained within the electrolytic cell to remove one or more of the target contaminants. That is, the fixing agent containing insoluble rare earth can be contacted with the electrolytic solution contained within the electrolytic cell to form an insoluble binding agent loaded with target material. The insoluble fixing agent loaded with target material can be separated from the electrolytic solution by any liquid solid separation process. The insoluble fixing agent loaded with separate target material can be contacted with a separation agent as described.
In another embodiment, an electrolytic current is contacted with the rare earth binding agent to remove one or more of the target contaminants. The electrolytic current can be rich or poor in the valuable metal. That is, the electrolytic current may comprise an electrolytic current before, after or during electrodeposition of the valuable metal contained within the electrolytic current.
A number of variations and modifications of the invention can be used. It would be possible to provide some characteristics of the invention without providing others.
The present invention, in various embodiments, configurations or aspects, includes components, methods, processes, systems and / or apparatuses substantially as represented and described herein, including various embodiments, configurations, aspects, subcombinations and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, configurations, and aspects, including the provision of devices and processes in the absence of items not represented and / or described herein or in various embodiments, configurations or aspects thereof, including in the absence of such items as they may have been used in previous devices or processes, for example, to improve performance, achieving ease and / or cost reduction of implementation.
The above discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the above detailed description for example, various features of the invention are grouped together in one or more embodiments, configurations, or aspects for the purpose of summarizing the description. The characteristics of the modalities, configurations or aspects of the invention can be combined in modalities, configurations or alternating aspects different from those discussed in the foregoing. This method of description is not to be construed as reflecting an intention that the claimed invention requires more features that are expressly cited in each claim. Rather, as the following claims reflect, the inventive aspects depend on less than all of the features of a single previously disclosed embodiment, configuration or aspect. Thus, the following claims are incorporated herein in this detailed description, with each claim being pointed out by itself as a separate preferred embodiment of the invention.
On the other hand, although the description of the invention has included the description of one or more embodiments, configurations or aspects and certain variations and modifications, other variations, combinations and modifications are within the scope of the invention, for example, as may be within the skill and knowledge of those in the art, after understanding the present description. It is proposed to obtain the rights that include modalities, configurations or alternative aspects to the permitted degree, including alternate, interchangeable and / or equivalent structures, functions, intervals or stages to those claimed, whether or not such alternate, interchangeable structures or equivalents, functions, intervals or stages are disclosed herein, and without proposing to publicly dedicate any patentable subject matter.