Background technology
Flyash is the solid waste that coal-burning power plant discharges.At present, the more than one hundred million ton of China's flyash annual emissions, total volume of cargo in storage of China's flyash has tens00000000 tons.A large amount of soil is is not only occupied in the discharge of a large amount of flyash, and serious environment pollution, constitutes the dual destruction to ecosystem environment.Therefore the comprehensive utilization carrying out flyash has Great significance and long-range strategic importance.Equally, China is the country that a bauxite resource is not rich in, and has document announcement China 45 kinds of Prospecting Target of The Main Minerals to the guaranteed extent of demand in 2010, has 10 kinds of mineral products to belong to and can not ensure, comprising bauxite.According to the rate of growth of current aluminum oxide output and bauxite exploitation, utilize in waste, even if consider prospective reserves, the time limit of the bauxite of China is also difficult to reach 50 years.So the method solving this crisis of resource has two kinds: one to be the existing bauxite resource of Appropriate application; Two is actively look for and utilize other to contain bauxite resource.And aluminum oxide is one of main component of flyash, its massfraction is generally 15% ~ 40%, reaches as high as 58%.So, carry out the pollution that the research work of extracting aluminum oxide from flyash can solve flyash, turn waste into wealth.
At present, that from flyash, extracts the research comparative maturity of aluminum oxide has limestone sintering process and soda-lime sintering process, is commonly referred to as alkaline process both this.In December, 2004, Inner Mongolia Autonomous Region Science and Technology Department held " flyash extracts aluminum and coproducing cement industrialization technology " project appraisal of scientific and technological achievements meeting of Liao Mengxi new and high technology Group Co., Ltd research and development, what adopt is exactly the soda-lime sintering process improved, this group independently completes the pilot scale of nearly 5000 tonnes, and obtains multinomial patent.But in alkalinity extraction flyash also there are some problems in aluminum oxide, the mainly calcium silicate slag of 1. sintering process generation, cement raw material can only be used as, the aluminum oxide often producing 1 ton will produce the calcium silicate slag being several times as much as flyash, and cement has it to sell radius accordingly, if locality does not have large-scale Cement industry support to cause secondary pollution; 2. sintering process is only extracted the aluminum oxide in flyash, and the utility value of its silicon-dioxide is low.3. the facility investment of sintering process treated coal ash is large, and energy consumption is high, and cost is high.
Because the alumina silica ratio of flyash is very low, be generally all less than 1, so adopt acidic process flyash more reasonable in principle.Acid system leaches the aluminum oxide in flyash, and the aluminium salt of generation can be made to enter solution, silicon not with acid-respons, completely in solid phase slag.Acidic process flyash can overcome the deficiency of sintering process, can not produce the solid waste more than raw material powder coal ash, and after extracting aluminum oxide, silicon-dioxide meeting enrichment, in slag, its content can reach 80 ~ 90%, is so more conducive to it and utilizes.Due to flyash be through high-temp combustion after cool rapidly, so glassy phase accounts for significant proportion, its chemically reactive is very low, and therefore, the extraction yield that improve aluminum oxide in flyash will be started with from improving the chemically reactive of flyash.The method of current document announcement is in acid-leaching reaction, add fluorochemical hydrotropy, silicon is combined with fluorine, reach the object discharging wherein aluminum oxide, but may the obnoxious flavoures such as HF be produced in the process of hydrotropy, fluorine-containing waste liquid and waste residue can be discharged again in the process of removing fluorine purifying, not only pollute the environment, and the potential safety hazard to operator can be caused.
Adopt the aluminum oxide in hydrochloric acid method leaching flyash, the mixed serum of hydrochloric acid and flyash is needed to be heated to 130 ~ 180 DEG C, and the necessary concentration of hydrochloric acid is higher with the leaching yield ensureing aluminum oxide in flyash, under the condition of concentrated hydrochloric acid, heat-processed equipment corrosion is serious, seriously constrains the development and apply of hydrochloric acid method.In this context, the present invention adopts hydrogen chloride gas directly to enter reactor, and does not participate in heat-processed, both ensure that the concentration of hydrochloric acid needed for reaction process, by the corrosion harmfulness avoiding concentrated hydrochloric acid heat-processed to bring.
Summary of the invention
The invention provides the method for a kind of HCl treatment coal ash for manufacturing for aluminum oxide for solving the problems of the technologies described above, object is the heat-processed equipment significant corrosion problems that solution hydrochloric acid method is brought, and produces the metallurgical-grade aluminum oxide of applicable Aluminium Industry.
A kind of HCl treatment coal ash for manufacturing of the present invention is for the method for aluminum oxide for achieving the above object, comprises the steps: that (1) is by flyash activating; (2) by the mixed in hydrochloric acid of flyash and 5% ~ 10% concentration after activation, in mixed slurries feeding heat exchanger, 90 DEG C ~ 200 DEG C are heated to; (3) slip after heating is sent in reactor, simultaneously in reactor, add hydrogen chloride gas, overall HCl is 4 ~ 9 with the mol ratio of aluminum oxide in flyash and ferric oxide, and a part of HCl passes through step (2) and adds, residue HCl adds at this, reaction times 1 h ~ 8h; (4) solid-liquid separation after reaction cooling, obtains aluminum chloride and ferric chloride Solution and high white residue, obtains crystal aluminum chloride and iron(ic) chloride after evaporation concentration or drying; (5) crystal aluminum chloride thermal degradation obtains the thick γ-Al containing a large amount of impurity2o3and hydrogen chloride gas; (6) thick γ-Al2o3adopt bayer process process to prepare metallurgical-grade aluminum oxide, residue is high scum, can as iron-smelting raw material.
Described activation is the one of mechanical activation or thermal activation.
Described mechanical activation adopts the one in vibration mill, vertical mill, planetary mills or high-energy ball milling.
Described thermal activation flyash is heated to 230 DEG C ~ 800 DEG C.
Described heat exchanger is the one in direct heat exchanger or indirect heat exchanger.
One in described indirect heat exchanger heating employing saturation steam, superheated vapour, thermal oil or fused salt is as thermal source.
Described direct heat exchanger heating adopts one in saturation steam or superheated vapour as thermal source.
The liner of described reactor is the one in acid-proof ceramic tile, enamel, glass, fluoroplastics or tetrafluoroethylene.
In step 4, the solid-liquid separation of liquor alumini chloridi and slag adopts the one in flocculating settling, pressure filtration or vacuum filtration.
Described liquor alumini chloridi evaporative crystallization adopts the one or more combination in multiple-effect falling film evaporation, forced circulation evaporation crystallization, drum dried or spraying dry.
Described crystal aluminum chloride decomposition temperature is 400 DEG C ~ 800 DEG C, obtains thick γ-Al2o3and hydrogen chloride gas.
Drying is carried out to hydrogen chloride gas, adopts the one of vitriol oil drying or molecular sieve drying.
The described thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.
Described high white residue is used for preparing high silicon filler, white carbon black, silica gel or water glass.
Dry hydrogen chloride gas is delivered in reactor.
Advantageous effect of the present invention: the present invention adopts flyash activating technology, does not add any auxiliary agent, and aluminum oxide in flyash can be made effectively to leach, and the leaching yield of aluminum oxide can reach more than 80%.Present invention achieves the circulation of acid circulation and alkali, whole process does not have the discharge of waste gas, waste liquid, waste residue.The present invention adopts hydrogen chloride gas directly to enter reactor, and does not participate in heat-processed, both ensure that the concentration of hydrochloric acid needed for reaction process, by the corrosion harmfulness avoiding concentrated hydrochloric acid heat-processed to bring, makes whole technique more be beneficial to industrialization.
Embodiment
Raw material powder coal ash consists of: Al2o3: 41%, SiO2: 48%, Fe2o3: 3.3%, CaO:3.3%, TiO2: 1.3%, MgO:0.2%.Flyash in following embodiment is 1000kg.The composition of raw material powder coal ash also can adopt other moiety and concrete consumption, and the flyash of any routine is all passable, and this can not be used for limiting protection scope of the present invention.
embodiment 1
Flyash is adopted vibration mill mechanical activation, the supplementary hydrochloric acid of 5% concentration and washing lotion and flyash are mixed into slip, with sending in reactor that liner is acid-proof ceramic tile after saturation steam indirect heating to 160 DEG C in indirect heat exchanger, pass into the hydrogen chloride gas through vitriol oil dried recovered, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 6.5, reaction times 2h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts flocculating settling, aluminum chloride liquid adopts spraying dry to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 400 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing high silicon filler.High scum is used for smelting iron.
embodiment 2
Raw material powder coal ash in embodiment 1 is adopted vertical mill mechanical activation, the supplementary hydrochloric acid of 10% concentration and washing lotion and flyash are mixed into slip, with sending in reactor that liner is enamel after superheated vapour indirect heating to 190 DEG C in indirect heat exchanger, pass into the hydrogen chloride gas through vitriol oil dried recovered, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 7.5, reaction times 3h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts flocculating settling, aluminum chloride liquid adopts drum dried to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 500 DEG C2o3and hydrogen chloride gas, hydrogenchloride molecular sieve drying reclaims and realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing white carbon black.High scum is used for smelting iron.
embodiment 3
Raw material powder coal ash in embodiment 1 is adopted planetary mills mechanical activation, 8% concentration is supplemented hydrochloric acid and washing lotion and flyash and is mixed into slip, with sending in reactor that liner is glass after thermal oil indirect heating to 200 DEG C in indirect heat exchanger, pass into the hydrogen chloride gas through vitriol oil dried recovered, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 9, reaction times 1h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts flocculating settling, aluminum chloride liquid adopts forced circulation evaporation crystallization to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 600 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing high silicon filler or water glass.High scum is used for smelting iron.
embodiment 4
Raw material powder coal ash in embodiment 1 is adopted the activation of high-energy ball milling machinery, 6% concentration is supplemented hydrochloric acid and washing lotion and flyash and is mixed into slip, with sending in reactor that liner is acidproof fluoroplastics after fused salt indirect heating to 150 DEG C in indirect heat exchanger, pass into the hydrogen chloride gas through vitriol oil dried recovered, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 5.5, reaction times 3.5h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts flocculating settling, aluminum chloride liquid adopts multiple-effect falling film evaporation to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 500 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing silica gel.High scum is used for smelting iron.
embodiment 5
By the raw material powder coal ash heat-activated in embodiment 1, activation temperature 800 DEG C, 7% concentration is supplemented hydrochloric acid and washing lotion and flyash and is mixed into slip, with sending in reactor that liner is tetrafluoroethylene after superheated vapour direct heating to 120 DEG C in direct heat exchanger, pass into the hydrogen chloride gas reclaimed through molecular sieve drying, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 6.5, reaction times 4h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts flocculating settling, aluminum chloride liquid adopts spraying dry to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 650 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing water glass.High scum is used for smelting iron.
embodiment 6
By the raw material powder coal ash heat-activated in embodiment 1, activation temperature 600 DEG C, 9% concentration is supplemented hydrochloric acid and washing lotion and flyash and is mixed into slip, with sending in reactor that liner is tetrafluoroethylene after saturation steam direct heating to 90 DEG C in direct heat exchanger, pass into the hydrogen chloride gas reclaimed through molecular sieve drying, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 6.5, reaction times 8h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts flocculating settling, aluminum chloride liquid adopts spraying dry to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 500 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing high silicon filler, white carbon black, silica gel and water glass.High scum is used for smelting iron.
embodiment 7
By the raw material powder coal ash heat-activated in embodiment 1, activation temperature 230 DEG C, 7% concentration is supplemented hydrochloric acid and washing lotion and flyash and is mixed into slip, with sending in reactor that liner is tetrafluoroethylene after superheated vapour direct heating to 130 DEG C in direct heat exchanger, pass into the hydrogen chloride gas reclaimed through molecular sieve drying, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 6, reaction times 5h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts vacuum filtration, aluminum chloride liquid adopts spraying dry to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 650 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing high silicon filler.High scum is used for smelting iron.
embodiment 8
By the raw material powder coal ash heat-activated in embodiment 1, activation temperature 350 DEG C, supplementary hydrochloric acid and washing lotion and flyash are mixed into slip, with sending in reactor that liner is tetrafluoroethylene after superheated vapour direct heating to 110 DEG C, pass into the hydrogen chloride gas reclaimed through molecular sieve drying, in hydrogenchloride and above-mentioned supplementary hydrochloric acid, in HCl and flyash, the mol ratio of the summation of aluminum oxide and ferric oxide is 4, reaction times 3.5h, solid-liquid separation after reaction cooling, obtain aluminum chloride liquid, the solid-liquid separation of liquor alumini chloridi and high white residue adopts pressure filtration, aluminum chloride liquid adopts spraying dry to obtain crystal aluminum chloride, aluminum chloride crystal decomposes and obtains thick γ-Al at 800 DEG C2o3and hydrogen chloride gas, hydrogenchloride vitriol oil dried recovered realizes recycle.Calcine the thick γ-Al obtained2o3standard compliant metallurgical-grade aluminum oxide and high scum is obtained through bayer process process.The thick γ of bayer process process-Al2o3prepare metallurgical-grade aluminum oxide process and comprise raw pulp allotment, low temperature stripping, high scum separating, washing, essence filter, seminal fluid cooling, seeded precipitation, Spawn preparation, aluminium hydroxide separating, washing, Aluminium hydroxide roasting, aluminum oxide packaging and accumulating and mother liquid evaporation operation.High white residue is used for preparing high silicon filler.High scum is used for smelting iron.