CN112756376A

Movatterモバイル変換

Info

Publication number: CN112756376A
Application number: CN202011597742.9A
Authority: CN
Inventors: 黄涛; 宋东平; 张树文; 周璐璐; 徐娇娇
Original assignee: Changshu Institute of Technology
Current assignee: Zhejiang Chuxiao Environmental Technology Co ltd
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-05-07
Anticipated expiration: 2040-12-29
Also published as: CN112756376B

Abstract

Translated fromChinese

本发明公开了一种垃圾焚烧飞灰同步固钙脱氯水洗方法，所述方法将磷酸钠和硅酸钠混合制成磷硅添加剂与垃圾焚烧飞灰和水混合，连续搅拌，静置陈化，固液分离得到固钙脱氯飞灰泥。该方法是一种垃圾焚烧飞灰水洗新思路，既可实现垃圾焚烧飞灰高效脱氯又可显著降低飞灰水洗液中重金属和钙离子的浓度，从而降低下游飞灰水洗废液处理压力。最高可实现垃圾焚烧飞灰中96％以上氯的脱除，最高可实现将98％以上钙截留在水洗后的固钙脱氯飞灰泥中，最高降低水洗废液中99％以上重金属浸出。

The invention discloses a method for simultaneous solid calcium dechlorination and water washing of waste incineration fly ash. The method comprises the following steps: mixing sodium phosphate and sodium silicate to prepare phosphosilicate additive, mixing waste incineration fly ash and water, continuously stirring, and standing for aging. , solid-liquid separation to obtain solid calcium dechlorination fly plaster. This method is a new idea of washing waste incineration fly ash, which can not only achieve efficient dechlorination of waste incineration fly ash, but also significantly reduce the concentration of heavy metals and calcium ions in the fly ash washing solution, thereby reducing the downstream fly ash washing wastewater treatment pressure. Up to 96% of chlorine can be removed from waste incineration fly ash, and up to 98% of calcium can be retained in the washed solid-calcium dechlorinated fly ash, which can reduce up to 99% of heavy metal leaching in the washing waste.

Description

Synchronous calcium fixation dechlorination water washing method for waste incineration fly ash

Technical Field

The invention relates to a synchronous calcium fixation dechlorination water washing method for waste incineration fly ash, belonging to the field of harmless treatment and resource utilization of hazardous wastes.

Background

The waste incineration fly ash refers to a particulate matter generated by condensation or chemical reaction of substances such as heavy metals, inorganic salts and the like volatilized under a high temperature condition in a waste incineration process. Fly ash from waste incineration is still listed in catalog of hazardous waste (2021 edition) at present. The waste incineration fly ash not only contains heavy metal and dioxin pollutants, but also contains 5 to 25 percent of chlorine. Typically, the content of chlorine in the grate fly ash is significantly higher than in the fluidized bed fly ash. Currently, the most main resource products of the waste incineration fly ash comprise three types, namely cement, vitreous body and ceramsite. However, the chlorine content of cement, glass body and ceramsite is very strict, for example, according to the related cement quality standard, the chlorine content in cement can not exceed 0.06%, and for example, according to the related light aggregate quality standard, the chlorine content in sintered or sintered ceramsite can not exceed 0.02%. Meanwhile, if the fly ash is not subjected to dechlorination pretreatment in the process of firing cement, glass bodies and ceramsite by utilizing the waste incineration fly ash, a large amount of chlorine in the fly ash is easily converted into atmosphere in the firing process, so that the waste gas treatment cost is increased, and the corrosion of a furnace body is accelerated.

Therefore, before the fly ash is subjected to resource conversion, dechlorination pretreatment is carried out on the fly ash. At present, a water washing method is one of the most common methods for dechlorinating waste incineration fly ash. Although the water washing method can realize effective dechlorination of the waste incineration fly ash, the water washing method also has a plurality of defects. For example, the fly ash washing process generates a large amount of washing waste liquid, which belongs to secondary dangerous waste and contains a large amount of salt, calcium, chlorine, heavy metals and dioxin pollutants. The process of treating the water washing waste liquid comprises the steps of decalcification, filtration and evaporative crystallization. However, the existing washing waste liquid has low decalcification efficiency, so that the calcium impurity content in the waste salt generated by evaporative crystallization is high. Meanwhile, the heavy metals contained in the crystallized waste salt are difficult to separate, so that the further treatment and utilization of the waste salt are limited.

Therefore, if a novel water washing method can be developed, the key for solving the current water washing bottleneck is to reduce the migration of calcium and heavy metals from fly ash particles to a water body in the water washing process on the premise of ensuring effective dechlorination.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a synchronous calcium fixation dechlorination water washing method for waste incineration fly ash.

The technical scheme is as follows: the invention relates to a synchronous calcium fixation dechlorination water washing method for waste incineration fly ash, which comprises the following steps:

(1) mixing sodium phosphate and sodium silicate to obtain a phosphorus-silicon additive;

(2) mixing the phosphorus-silicon additive with the waste incineration fly ash to obtain silicon-doped phosphorus fly ash;

(3) adding water into the silicon-phosphorus doped fly ash, mixing, continuously stirring, standing and aging to obtain calcium-fixing fly ash slurry;

(4) carrying out solid-liquid separation on the calcium-fixing fly ash slurry to obtain solid part which is calcium-fixing fly ash;

(5) mixing water and calcium-fixing fly ash mud, and continuously stirring to obtain calcium-fixing dechlorination fly ash mortar;

(6) and (3) carrying out solid-liquid separation on the calcium-fixing dechlorination flying mortar to obtain a solid part, namely the calcium-fixing dechlorination flying mortar.

In the step (1), the molar ratio of the sodium phosphate to the sodium silicate is 1-4: 10.

In the step (2), the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash is 2-20: 100.

In the step (3), the solid-to-solid ratio of the water to the silicon-phosphorus-doped fly ash liquid is 0.3-0.9: 1, the continuous stirring time is 1-6 hours, and the standing and aging time is 12-48 hours.

Wherein, in the step (4) and the step (6), one of a plate filter press and a centrifuge is used for the solid-liquid separation.

In the step (5), the liquid-solid ratio of the water to the calcium-fixing fly ash is 1-3: 1, and the continuous stirring time is 1-6 h.

The reaction mechanism is as follows: in the invention, after water and fly ash doped with silicon and phosphorus are mixed, sodium phosphate, sodium silicate and alkali salt in the fly ash are quickly dissolved in the stirring process. During aging, the phosphate dissolved in the slurry reacts with the calcium oxide and calcium carbonate in the fly ash to form hydroxyapatite, while the silicate reacts with the calcium oxide and calcium carbonate in the fly ash to form calcium silicate. Calcium in fly ash slurry achieves effective fixation through the formation of hydroxyapatite and calcium silicate. Meanwhile, the hydroxyapatite and the calcium silicate can transfer heavy metal ions dissolved in the water body to the solid phase again through ion exchange and electrostatic adsorption. Under the alkali excitation action, calcium silicate and hydroxyapatite can further react to generate calcium silicophosphate, so that heavy metal and calcium in fly ash can be further stabilized. The calcium-fixing fly ash slurry is led into a plate filter press or a centrifuge for solid-liquid separation to remove free chloride ions. The water and the calcium fixation fly ash mud are mixed, and the chloride ions adsorbed on the surface of the calcium fixation fly ash mud can be promoted to be resolved into a water body in the stirring process, so that the fly ash can be synchronously fixed with calcium and heavy metals, and dechlorination can be maximized.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: the method can realize the efficient dechlorination of the waste incineration fly ash and can obviously reduce the concentration of heavy metal and calcium ions in the fly ash water washing liquid, thereby reducing the treatment pressure of the downstream fly ash water washing waste liquid, and the method is a new idea for the waste incineration fly ash water washing. The method can realize the removal of more than 96 percent of chlorine in the waste incineration fly ash to the maximum extent; the highest calcium retention rate can be realized, more than 98 percent of calcium is retained in the water-washed calcium-fixing dechlorination fly ash; the leaching of more than 99 percent of heavy metal in the washing waste liquid is reduced to the maximum.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings

The household garbage incineration fly ash is taken from a certain normally-cooked garbage incineration power plant and collected by a bag-type dust collector. The waste incineration fly ash sample mainly contains 30-45% of CaO, 10-20% of Cl and 6-12% of Na₂O、6％～12％K₂O、3％～8％SO₂、3％～8％SiO₂、2％～6％MgO、2％～6％Fe₂O₃、2％～6％Al₂O₃、0.5％～1.5％CrO₃0.1 to 0.5 percent of CdO, 0.1 to 0.5 percent of NiO, 0.1 to 0.5 percent of PbO and the like.

Example 1 the effect of sodium phosphate and sodium silicate molar ratio on fly ash calcium solidification rate, percent reduction in heavy metal leaching, chlorine elution rate

The treatment process of the invention comprises the following steps: and respectively weighing sodium phosphate and sodium silicate according to the molar ratio of the sodium phosphate to the sodium silicate of 0.5:10, 0.7:10, 0.9:10, 1:10, 2.5:10, 4:10, 4.5:10, 5:10 and 6:10, and mixing to obtain the nine groups of phosphorus-silicon additives. And weighing the phosphorus-silicon additive and the waste incineration fly ash respectively according to the mass ratio of 2:100 of the phosphorus-silicon additive to the waste incineration fly ash, and mixing to obtain nine groups of silicon-doped phosphorus fly ash. And respectively weighing water and the silicon-phosphorus doped fly ash according to the liquid-solid ratio of 0.3:1, mixing, continuously stirring for 1h, standing and aging for 12h to obtain nine groups of calcium fixation fly ash. And (3) introducing the calcium-fixed fly ash slurry into a plate-type filter press for solid-liquid separation to obtain solid part calcium-fixed fly ash. And (3) weighing water and calcium-fixing fly ash according to the liquid-solid ratio of 1:1, mixing, and continuously stirring for 1h to obtain nine groups of calcium-fixing dechlorination fly ash. And (3) introducing the nine groups of calcium-fixing dechlorination fly ash slurry into a plate type filter press for solid-liquid separation to obtain solid calcium-fixing dechlorination fly ash, wherein the solid part is water washing waste liquid, and the total of the nine groups are respectively nine.

And (3) contrast treatment process: and (3) weighing water and the waste incineration fly ash according to the liquid-solid ratio of 1.3:1, mixing, and continuously stirring for 1h to obtain fly ash slurry. And (3) introducing the fly ash slurry into a plate-type filter press for solid-liquid separation to obtain dechlorinated fly ash as a solid part and washing waste liquid as a liquid part.

Determination of the calcium content in the solid sample: the calcium content of the waste incineration fly ash raw sample and the calcium-fixing dechlorination fly ash is measured according to the content measurement of calcium, magnesium and sulfur in the compound fertilizer (GB T19203-2003).

Calculation of calcium cure rate: the calcium retention rate of the waste incineration fly ash is calculated according to the formula (1), J_CaIs calcium solidification rate, wherein c_Ca0And c_CatThe calcium contents (%) of the raw waste incineration fly ash and the calcium-fixing dechlorinated fly ash are respectively.

Determination of the chlorine content in the solid sample: the chlorine content in the waste incineration fly ash raw sample and the calcium-fixing dechlorination fly ash is measured according to the construction sand (GB/T14684-.

Calculation of chlorine elution rate: the chlorine removal rate of the waste incineration fly ash is calculated according to the formula (2), R_ClFor chlorine removal efficiency, wherein c_Cl0And c_CltThe chlorine contents (%) of the waste incineration fly ash raw sample and the calcium fixation dechlorinated fly ash are respectively.

And (3) determining the concentrations of chromium, nickel, lead and cadmium in the liquid: the concentrations of the nickel, lead and cadmium in the water washing waste liquid obtained in the treatment process and the comparative treatment process are measured according to an inductively coupled plasma emission spectrometry (HJ 776-2012015) for measuring 32 elements in water quality, and the concentration of the chromium pollutant is measured according to a flow injection-dibenzocarbonyl dihydrazide photometry (HJ 908-2017) for measuring hexavalent chromium in water quality.

The percentage reduction of leaching of chromium, nickel, lead and cadmium is calculated as follows: the percent reduction in leaching of chromium, nickel, lead and cadmium is calculated according to equation (3), where R_MReducing the leaching percentage of chromium, nickel, lead and cadmium (M is chromium, nickel, lead and cadmium), c_M0Concentrations of chromium, nickel, lead, cadmium (mg/L) in the aqueous waste for comparative treatment, and c_MtThe concentrations (mg/L) of chromium, nickel, lead and cadmium in the water washing waste liquid in the treatment process of the invention are shown.

The test results of this example are shown in tables 1 and 2.

TABLE 1 table of calcium content and chlorine content in fly ash as raw material, heavy metal concentration in washing waste liquid in comparative treatment process, and calcification content and chlorine content in calcium fixation dechlorination fly ash and heavy metal concentration in washing waste liquid under the influence of different molar ratios of sodium phosphate and sodium silicate in treatment process of the invention

Table 2 table of the effect of sodium phosphate and sodium silicate molar ratio on fly ash calcium solidification rate, percentage reduction in heavy metal leaching, and chlorine elution rate

As can be seen from Table 1, the calcium content of the fly ash is 27.15%, the chlorine content is 18.34%, and the concentrations of chromium, nickel, lead and cadmium in the washing waste liquid in the comparative treatment process are 978.24mg/L, 345.13mg/L, 267.45mg/L and 131.62mg/L, respectively. Meanwhile, the content of calcium in the calcium-fixing dechlorination flying plaster, the content of chlorine in the calcium-fixing dechlorination flying plaster and the concentration of heavy metals in the water washing waste liquid obtained by contrasting the treatment process are all influenced by the change of the molar ratio of the sodium phosphate to the sodium silicate. Specifically, as can be seen from the analysis in table 2, when the molar ratio of sodium phosphate to sodium silicate is less than 1:10, the amount of sodium phosphate is less, the amount of generated hydroxyapatite is reduced, so that the amount of heavy metal ions adsorbed by ion exchange in the hydroxyapatite is reduced, resulting in a significant reduction in the percentage of reduction in leaching of heavy metals as the molar ratio of sodium phosphate to sodium silicate is reduced. When the molar ratio of the sodium phosphate to the sodium silicate is 1-4: 10, hydroxyapatite can be formed by the phosphate and calcium oxide and calcium carbonate in the fly ash in the aging process, and calcium silicate is formed by the silicate and calcium oxide and calcium carbonate in the fly ash. Both hydroxyapatite and calcium silicate can adsorb and stabilize calcium and heavy metals dissolved from fly ash into water. Meanwhile, under the alkali excitation action, calcium silicate and hydroxyapatite can further react to generate a calcium silicophosphate substance, so that the heavy metal and calcium in the fly ash can be further stabilized. Finally, the calcium solidification rate is greater than 94%, the chlorine desorption rate is greater than 92%, and the heavy metal leaching reduction percentage is greater than 92%. When the molar ratio of the sodium phosphate to the sodium silicate is more than 4:10, the generated hydroxyapatite is excessive, the ion exchange property of calcium, chlorine and heavy metal is enhanced, and the reduction percentages of the calcium solidification rate, the chlorine desorption rate and the heavy metal leaching are all obviously reduced along with the further increase of the molar ratio of the sodium phosphate to the sodium silicate. Therefore, the benefit and the cost are combined, and when the molar ratio of the sodium phosphate to the sodium silicate is 1-4: 10, the fly ash calcium solidification rate, the heavy metal leaching reduction percentage and the chlorine elution rate are improved.

Example 2 the quality ratio of fly ash calcium solidification rate, heavy metal leaching reduction percentage, chlorine elution rate influence of phosphorus silicon additive and waste incineration fly ash

And respectively weighing sodium phosphate and sodium silicate according to the molar ratio of 4:10 of the sodium phosphate to the sodium silicate, and mixing to obtain the phosphorus-silicon additive. And respectively weighing the phosphorus-silicon additive and the waste incineration fly ash according to the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash of 1:100, 1.5:100, 1.8:100, 2:100, 11:100, 20:100, 21:100, 23:100 and 25:100, and mixing to obtain nine groups of silicon-doped phosphorus fly ash. And (3) respectively weighing water and the silicon-phosphorus doped fly ash according to the liquid-solid ratio of 0.6:1, mixing, continuously stirring for 3.5 hours, standing and aging for 30 hours to obtain nine groups of calcium fixation fly ash. And (3) introducing the nine groups of calcium-fixing fly ash slurry into a centrifuge for solid-liquid separation to obtain nine groups of calcium-fixing fly ash slurry as solid parts. Weighing water and calcium fixation fly ash according to the liquid-solid ratio of 2:1, mixing, and continuously stirring for 3.5h to obtain nine groups of calcium fixation dechlorination fly ash. And (3) introducing the nine groups of calcium-fixing dechlorination fly ash slurry into a centrifugal machine for solid-liquid separation to obtain solid calcium-fixing dechlorination fly ash, wherein the solid part is water washing waste liquid, and the total of the nine groups are respectively nine.

And (3) contrast treatment process: and (3) weighing water and the waste incineration fly ash according to the liquid-solid ratio of 2.6:1, mixing, and continuously stirring for 1h to obtain fly ash slurry. And (3) introducing the fly ash slurry into a plate-type filter press for solid-liquid separation to obtain dechlorinated fly ash as a solid part and washing waste liquid as a liquid part.

The measurement of calcium content, the measurement of chlorine content, the measurement of chromium, nickel, lead and cadmium concentrations in the washing waste liquid, the calculation of chlorine elution rate, the calculation of calcium solidification rate and the calculation of the leaching reduction percentage of heavy metals of chromium, nickel, lead and cadmium are the same as those in example 1, and the specific results are shown in tables 3 and 4.

TABLE 3 table of calcium content and chlorine content in fly ash raw sample, heavy metal concentration in washing waste liquid in comparative treatment process, and calcification content and chlorine content in calcium fixation dechlorination fly ash and heavy metal concentration in washing waste liquid under the influence of different mass ratios of phosphorus silicon additive and waste incineration fly ash in treatment process of the invention

TABLE 4 influence of the mass ratio of phosphorus-silicon additive to fly ash from incineration on the solidification rate of calcium in fly ash, the percentage reduction of heavy metal leaching, and the chlorine elution rate

As can be seen from Table 3, the calcium content of the fly ash was 28.54%, the chlorine content was 19.02%, and the concentrations of chromium, nickel, lead and cadmium in the washing waste liquid in the comparative treatment process were 824.76mg/L, 297.42mg/L, 221.68mg/L and 145.19mg/L, respectively. Meanwhile, the content of calcium in the calcium-fixing dechlorination flying plaster, the content of chlorine in the calcium-fixing dechlorination flying plaster and the concentration of heavy metals in the washing waste liquid obtained in the contrast treatment process are all influenced by the change of the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash. Specific influence conditions can be analyzed from table 4, and when the mass ratio of the phosphorus silicon additive to the waste incineration fly ash is less than 2:10, the mixing amount of the phosphorus silicon additive is less, and the generation amounts of hydroxyapatite, calcium silicate and calcium silicophosphate substances are reduced, so that the calcium solidification rate, the reduction percentage of heavy metal leaching and the chlorine elution rate are all obviously reduced along with the reduction of the mass ratio of the phosphorus silicon additive to the waste incineration fly ash. When the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash is 2-20: 10, in the aging process, calcium oxide and calcium carbonate in phosphate and fly ash can form hydroxyapatite, and calcium silicate and calcium oxide and calcium carbonate in fly ash form calcium silicate. Both hydroxyapatite and calcium silicate can adsorb and stabilize calcium and heavy metals dissolved from fly ash into water. Meanwhile, under the alkali excitation action, calcium silicate and hydroxyapatite can further react to generate a calcium silicophosphate substance, so that the heavy metal and calcium in the fly ash can be further stabilized. Finally, the calcium solidification rate is greater than 94%, the chlorine desorption rate is greater than 94%, and the heavy metal leaching reduction percentage is greater than 96%. When the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash is more than 20:10, the calcium solidification rate, the chlorine desorption rate and the heavy metal leaching reduction percentage are not obviously changed along with the further increase of the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash. Therefore, the benefit and the cost are combined, and when the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash is 2-20: 10, the fly ash calcium solidification rate, the heavy metal leaching reduction percentage and the chlorine desorption rate are improved most beneficially.

Example 3 Effect of aging time on fly ash calcium solidification Rate, percent reduction in heavy metal leaching, chlorine elution Rate

And respectively weighing sodium phosphate and sodium silicate according to the molar ratio of 4:10 of the sodium phosphate to the sodium silicate, and mixing to obtain the phosphorus-silicon additive. And respectively weighing the phosphorus-silicon additive and the waste incineration fly ash according to the mass ratio of 20:100 of the phosphorus-silicon additive to the waste incineration fly ash, and mixing to obtain the silicon-doped phosphorus fly ash. Respectively weighing water and the silicon-doped phosphorus fly ash according to the liquid-solid ratio of 0.9:1, mixing, continuously stirring for 6h, and respectively standing and aging for 6h, 8h, 10h, 12h, 30h, 48h, 54h, 60h and 66h to obtain the calcium-fixing fly ash slurry. And (3) introducing the calcium-fixing fly ash slurry into a centrifugal machine for solid-liquid separation to obtain solid part which is calcium-fixing fly ash. Respectively weighing water and calcium-fixing fly ash according to the liquid-solid ratio of 3:1, mixing, and continuously stirring for 6h to obtain calcium-fixing dechlorination fly ash. Introducing the calcium-fixed dechlorination flying mortar into a plate-type filter press for solid-liquid separation to obtain nine groups of solid parts from the calcium-fixed dechlorination flying mortar and liquid parts from the washing waste liquid.

And (3) contrast treatment process: and (3) weighing water and the waste incineration fly ash according to the liquid-solid ratio of 3.9:1, mixing, and continuously stirring for 1h to obtain fly ash slurry. And (3) introducing the fly ash slurry into a plate-type filter press for solid-liquid separation to obtain dechlorinated fly ash as a solid part and washing waste liquid as a liquid part.

The measurement of calcium content, the measurement of chlorine content, the measurement of chromium, nickel, lead and cadmium concentrations in the washing waste liquid, the calculation of chlorine elution rate, the calculation of calcium solidification rate and the calculation of the leaching reduction percentage of heavy metals of chromium, nickel, lead and cadmium are the same as those in example 1, and the specific results are shown in tables 5 and 6.

TABLE 5 tables of calcium content and chlorine content of fly ash as raw material, heavy metal concentration in washing waste liquid in comparative treatment process, and calcification content and chlorine content in calcium fixation dechlorination fly ash and heavy metal concentration in washing waste liquid under the influence of aging time in treatment process of the present invention

TABLE 6 influence of aging time on fly ash calcium solidification rate, heavy metal leaching reduction percentage, chlorine elution rate

As can be seen from Table 5, the calcium content of the fly ash was 28.17%, the chlorine content was 18.78%, and the concentrations of chromium, nickel, lead and cadmium in the washing waste liquid in the comparative treatment process were 889.52mg/L, 311.05mg/L, 219.31mg/L and 128.79mg/L, respectively. Meanwhile, the content of calcium in the calcium-fixing dechlorination flying plaster, the content of chlorine in the calcium-fixing dechlorination flying plaster and the concentration of heavy metals in the washing waste liquid obtained in the contrast treatment process are all influenced by the change of the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash. Specifically, as can be seen from the analysis in table 6, when the aging time is less than 12h, the aging time of the mortar is too short, and the formation of hydroxyapatite and calcium silicate is reduced, so that the calcium curing rate and the percentage reduction of leaching of heavy metals are both significantly reduced with the decrease of the aging time. When the aging time is 12-48 h, in the aging process, the phosphate and calcium oxide and calcium carbonate in the fly ash can form hydroxyapatite, and the silicate and calcium oxide and calcium carbonate in the fly ash form calcium silicate. Both hydroxyapatite and calcium silicate can adsorb and stabilize calcium and heavy metals dissolved from fly ash into water. Meanwhile, under the alkali excitation action, calcium silicate and hydroxyapatite can further react to generate a calcium silicophosphate substance, so that the heavy metal and calcium in the fly ash can be further stabilized. Finally, the calcium solidification rate is greater than 95%, the chlorine desorption rate is greater than 95%, and the heavy metal leaching reduction percentage is greater than 97%. When the aging time is more than 48 hours, excessive chlorine is adsorbed into the silico-calcium phosphate substance, resulting in a significant decrease in the chlorine elution rate with further increase in the aging time. Therefore, the benefit and the cost are combined, and when the aging time is equal to 12-48 h, the fly ash calcium solidification rate, the heavy metal leaching reduction percentage and the chlorine elution rate are improved.

Claims

Translated fromChinese

1.一种垃圾焚烧飞灰同步固钙脱氯水洗方法，其特征在于，包括以下步骤：1. a synchronous solid calcium dechlorination water washing method for waste incineration fly ash, is characterized in that, comprises the following steps:

(1)将磷酸钠和硅酸钠混合，得到磷硅添加剂；(1) mixing sodium phosphate and sodium silicate to obtain phosphorus silicon additive;

(2)将磷硅添加剂与垃圾焚烧飞灰混合，得到掺硅磷飞灰；(2) mixing the phosphorus-silicon additive with the waste incineration fly ash to obtain the silicon-doped phosphorus fly ash;

(3)向掺硅磷飞灰中加入水，混合，连续搅拌，静置陈化，得到固钙飞灰浆；(3) adding water to the silicon-phosphorus-doped fly ash, mixing, stirring continuously, and standing for aging to obtain solid calcium fly ash slurry;

(4)将固钙飞灰浆进行固液分离，得到的固体部分为到固钙飞灰泥；(4) solid-liquid separation is carried out with the solid-calcium fly ash, and the solid portion obtained is to the solid-calcium fly ash;

(5)将水和固钙飞灰泥混合，连续搅拌，得到固钙脱氯飞灰浆；(5) mixing water and solid calcium fly ash, stirring continuously to obtain solid calcium dechlorination fly ash;

(6)将固钙脱氯飞灰浆进行固液分离，得到的固体部分为到固钙脱氯飞灰泥。(6) The solid-liquid separation is carried out on the solid-calcium dechlorination fly ash, and the obtained solid part is the solid-calcium dechlorination fly ash.

2.根据权利要求1所述垃圾焚烧飞灰同步固钙脱氯水洗方法，其特征在于，步骤(1)中，所述磷酸钠和硅酸钠摩尔比1～4:10。2. The method for simultaneous solid calcium dechlorination and water washing of waste incineration fly ash according to claim 1, characterized in that, in step (1), the molar ratio of the sodium phosphate and sodium silicate is 1-4:10.

3.根据权利要求1所述垃圾焚烧飞灰同步固钙脱氯水洗方法，其特征在于，步骤(2)中，所述磷硅添加剂与垃圾焚烧飞灰质量比2～20:100。3 . The method for simultaneous solid calcium dechlorination and water washing of waste incineration fly ash according to claim 1 , wherein in step (2), the mass ratio of the phosphorus-silicon additive to the waste incineration fly ash is 2-20:100. 4 .

4.根据权利要求1所述垃圾焚烧飞灰同步固钙脱氯水洗方法，其特征在于，步骤(3)中，所述水和掺硅磷飞灰液固比0.3～0.9:1，连续搅拌时间为1～6h，静置陈化时间为12～48h。4. The method for simultaneous solid calcium dechlorination and water washing of waste incineration fly ash according to claim 1, characterized in that, in step (3), the water and the silicon phosphorus-doped fly ash have a liquid-solid ratio of 0.3 to 0.9:1, and are continuously stirred. The time is 1-6h, and the standing and aging time is 12-48h.

5.根据权利要求1所述垃圾焚烧飞灰同步固钙脱氯水洗方法，其特征在于，步骤(4)和步骤(6)中，所述固液分离使用板式压滤机或离心机中的一种。5. The synchronous solid calcium dechlorination water washing method for waste incineration fly ash according to claim 1, is characterized in that, in step (4) and step (6), described solid-liquid separation uses plate filter press or centrifuge in the A sort of.

6.根据权利要求1所述垃圾焚烧飞灰同步固钙脱氯水洗方法，其特征在于，步骤(5)中，所述水和固钙飞灰泥液固比1～3:1，连续搅拌时间为1～6h。6. The method for simultaneous solid-calcium dechlorination water washing of waste incineration fly ash according to claim 1, characterized in that, in step (5), the water and the solid-calcium fly ash liquid-solid ratio of 1～3:1 are continuously stirred. The time is 1～6h.