CN109775743B - Method for extracting pure calcium fluoride from calcium fluoride sludge - Google Patents
Method for extracting pure calcium fluoride from calcium fluoride sludge Download PDFInfo
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- CN109775743B CN109775743B CN201910220579.5A CN201910220579A CN109775743B CN 109775743 B CN109775743 B CN 109775743B CN 201910220579 A CN201910220579 A CN 201910220579A CN 109775743 B CN109775743 B CN 109775743B
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Abstract
The invention discloses a method for extracting pure calcium fluoride from calcium fluoride sludge, which comprises the following steps: 1) pulping and dissolving; 2) removing silicon from caustic soda to obtain a filter cake A and a solution A; 3) calcium salt conversion; 4) acidifying with hydrochloric acid to obtain calcium fluoride and a solution C; 5) drying and crushing: and (3) drying the acidified calcium fluoride in a 105 ℃ oven, and crushing the calcium fluoride by a crusher to obtain a pure powdery calcium fluoride product. The invention can effectively treat the calcium fluoride sludge, avoid secondary pollution, and simultaneously can recover the calcium fluoride in the sludge, thereby solving the problem of fluorine resource shortage.
Description
Technical Field
The invention relates to the field of calcium fluoride sludge treatment, in particular to a method for extracting pure calcium fluoride from calcium fluoride sludge.
Background
Calcium fluoride sludge is mainly from inorganic and organic fluorine chemical enterprises, touch screen production enterprises and photovoltaic industries, and a large amount of fluorine-containing wastewater is discharged in the process of treating products such as monocrystalline silicon wafers, battery pieces and components. The main method for treating the fluorine-containing wastewater by enterprises mainly adopts a chemical precipitation and coagulation method, and calcium chloride, calcium hydroxide or calcium carbonate is generally added to form calcium fluoride precipitate, and then flocculation treatment is carried out. The chemical precipitation method produces a large amount of sludge, and most of the sludge is composed of calcium fluoride, calcium carbonate, silicon dioxide and the like.
Calcium fluoride has low toxicity, is very easy to be absorbed by plants, is harmful to soil when being directly buried, and further poses threats to crop growth and human health. Calcium fluoride is slightly soluble in water, and secondary fluorine pollution can be caused by improper disposal, so that the fluorine content of surface water exceeds the standard. Therefore, disposal of calcium fluoride is essential.
The calcium fluoride has wide application range and is mainly used in three industries of metallurgy, chemical industry and building materials at present. In the smelting process, calcium fluoride can be used as a fluxing agent to reduce the melting point of refractory metal substances, and is widely applied to steel smelting, ferroalloy technology and non-ferrous metal smelting; in the chemical industry, calcium fluoride is a main raw material for producing various organic and inorganic fluorides; in cement production, fluorite as a mineralizer can reduce the sintering temperature of fuel and reduce fuel consumption. The available calcium fluoride resources are limited, but the demand for calcium fluoride is increasing with the development of industry, so that the recycling treatment of calcium fluoride sludge is the most ideal treatment method.
At present, the domestic treatment of calcium fluoride sludge mainly adopts high-temperature solidification and flotation methods. Slag generated after the calcium fluoride sludge and the urban domestic sewage sludge are co-melted can be subsequently recycled; the calcium fluoride sludge can replace part of raw materials to be sintered at high temperature to prepare ceramic; the calcium fluoride sludge can replace partial raw materials in the production of cement and concrete, so that the calcium fluoride sludge can be recycled. The flotation process is to add a flotation agent into a suspension emulsion formed by solid waste and water, and because the surface properties of the materials are different, a part of particles with good floatability are adsorbed with micro-bubbles in the water to form an air floating upper liquid surface with the density smaller than that of the water, thereby achieving the purpose of separating the materials. The high-temperature curing method has higher requirements on the content of calcium fluoride sludge components and consumes more electricity; the flotation process can produce a large amount of impurity mud and sewage containing metal ions and silicon dioxide during production, and secondary pollution is brought to the environment.
Disclosure of Invention
In view of the above problems in the prior art, the present applicant provides a method for extracting pure calcium fluoride from calcium fluoride sludge. The invention can effectively treat the calcium fluoride sludge, avoid secondary pollution, and simultaneously can recover the calcium fluoride in the sludge, thereby solving the problem of fluorine resource shortage.
The technical scheme of the invention is as follows:
a method for extracting pure calcium fluoride from calcium fluoride sludge, comprising the steps of:
1) pulping and dissolving: adding water into calcium fluoride sludge, heating and stirring to ensure that the sludge is uniformly dispersed to obtain a solid-liquid mixed solution;
2) removing silicon by using caustic soda: adding caustic soda flakes into the solid-liquid mixed solution prepared in the step (1), stirring to convert silicon dioxide in the sludge into sodium silicate, and filtering to obtain a filter cake A and a solution A
3) Calcium salt conversion: mixing the filter cake A with water, uniformly stirring, adding sodium carbonate to convert calcium sulfate in the filter cake A into calcium carbonate, reacting, and filtering to obtain a filter cake B and a solution B;
4) acidifying with hydrochloric acid: mixing the filter cake B with water, uniformly stirring, adding hydrochloric acid to dissolve the alkaline precipitate in the filter cake B, and filtering to obtain calcium fluoride and a solution C;
5) drying and crushing: and (3) drying the acidified calcium fluoride in a 105 ℃ oven, and crushing the calcium fluoride by a crusher to obtain a pure powdery calcium fluoride product.
In the step (1), water is added into the calcium fluoride sludge to disperse the sludge in the water, wherein the mass ratio of the calcium fluoride sludge to the water is 1: 1-1: 2.
In the step (1), the heating temperature is 50-60 ℃, and the sludge dissolution is accelerated.
The molar ratio of the addition amount of the caustic soda flakes to the content of silicon dioxide in the calcium fluoride sludge in the step (2) is 2:1, and the stirring time is 2 hours.
In the step (2), the solution A is a sodium silicate solution; and washing the filter cake A with water for multiple times.
In the step (3), the molar ratio of the addition amount of the sodium carbonate to the sulfate radical content in the sludge is 1.5:1, and the stirring reaction time is 2 hours.
The solution B in the step (3) is a mixed solution of sodium carbonate and sodium sulfate, sulfuric acid is added into the solution B to adjust the pH value to 6-7, and then a sodium sulfate solution is obtained; and washing the filter cake B with water for multiple times.
The molar ratio of the consumption of the hydrochloric acid to the content of calcium in the calcium fluoride sludge in the step (4) is 2:1, and the stirring reaction time is 1 h.
Adding calcium hydroxide into the solution C, adjusting the pH of the solution C to 7.5-8.5, and filtering to obtain a calcium chloride solution; the calcium fluoride is washed with water for a plurality of times.
The purity of calcium fluoride in the pure calcium fluoride product is more than or equal to 85 percent, the chloride is less than or equal to 0.01 percent, and P is used2O5Calculated as phosphate, is less than or equal to 0.01 percent by weight of Fe2O3Iron is less than or equal to 0.1 percent calculated as Al2O3Calculated aluminum is less than or equal to 0.1 percent.
The beneficial technical effects of the invention are as follows:
the invention takes sludge with low calcium fluoride content as raw material, and removes impurities in the sludge through purification step by step, thereby obtaining calcium fluoride with higher purity. Compared with the traditional method for treating calcium fluoride sludge, the method has simple process and is easy to realize batch continuous production in production; sludge with different component contents can be reasonably treated by adjusting the addition amount of a reagent; the method solves the problem of secondary fluorine pollution possibly caused in the calcium fluoride sludge treatment process, and simultaneously recovers the calcium fluoride contained in the calcium fluoride sludge, so that the sludge is recycled.
Drawings
FIG. 1 is a schematic view of the process of the present invention.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
Example 1
In the embodiment, calcium fluoride sludge generated in the photovoltaic industry is used as a raw material, the purity of calcium fluoride in raw sludge is 37.03%, and the calcium fluoride is treated according to the experimental method provided by the invention, and the specific steps are as follows.
Pulping and dissolving: 100g of calcium fluoride sludge is weighed and placed in a beaker, 100ml of water is added, and the mixture is heated and stirred for 30min at 50 ℃ to obtain uniformly dispersed solid-liquid mixed liquid.
Removing silicon by using caustic soda: adding 8g of sodium hydroxide into the solid-liquid mixed solution, stirring and reacting for 2 hours to completely convert silicon dioxide in the sludge into sodium silicate, and filtering to obtain a filter cake 1 and a sodium silicate solution; 100ml of water was added in 2 portions to the filter cake 1, washing the residual sodium salt in the filter cake.
Calcium salt conversion: adding 100ml of water into the filter cake 1, uniformly stirring, adding 2g of sodium carbonate to convert calcium sulfate in the filter cake 1 into calcium carbonate, stirring for reacting for 2 hours, and filtering to obtain a filter cake 2 and a mixed solution of sodium sulfate and sodium carbonate; adding 100ml of water into the filter cake 2 for 2 times, and cleaning the residual sodium salt in the filter cake; and adding 3ml of sulfuric acid into the mixed solution, adjusting the pH value of the mixed solution to 6, and concentrating to obtain sodium sulfate crystals, wherein the purity of the sodium sulfate is 98.5%.
Acidifying with hydrochloric acid: adding 100ml of water into the filter cake 2, uniformly stirring, adding 10ml of hydrochloric acid to dissolve the alkaline precipitate in the filter cake 2, and filtering to obtain 26g of calcium fluoride and calcium chloride solution (containing a small amount of impurities); adding 20g of calcium hydroxide into the calcium chloride solution, adjusting the pH value of the solution to 7.5, and filtering to obtain a pure calcium chloride solution, wherein the content of calcium chloride is 28%; 100ml of water is added into the calcium fluoride in 2 times, and the residual acidic calcium chloride solution in the calcium fluoride is washed.
Drying and crushing: and (3) drying the treated calcium fluoride in an oven at 105 ℃, and crushing by using a crusher to obtain 11g of powdery calcium fluoride product, wherein the purity of the calcium fluoride is 92%.
Example 2
In the embodiment, calcium fluoride sludge generated in the photovoltaic industry is used as a raw material, the purity of calcium fluoride in raw sludge is 37.03%, and the calcium fluoride is treated according to the experimental method provided by the invention, and the specific steps are as follows.
Pulping and dissolving: 100g of calcium fluoride sludge is weighed and placed in a beaker, 150ml of water is added, and the mixture is heated and stirred for 30min at 55 ℃ to obtain uniformly dispersed solid-liquid mixed liquid.
Removing silicon by using caustic soda: adding 8g of sodium hydroxide into the solid-liquid mixed solution, stirring and reacting for 2 hours to completely convert silicon dioxide in the sludge into sodium silicate, and filtering to obtain a filter cake 1 and a sodium silicate solution; 150ml of water was added in 2 portions to the filter cake 1, washing the residual sodium salt in the filter cake.
Calcium salt conversion: adding 150ml of water into the filter cake 1, uniformly stirring, adding 2g of sodium carbonate to convert calcium sulfate in the filter cake 1 into calcium carbonate, stirring for reacting for 2 hours, and filtering to obtain a filter cake 2 and a mixed solution of sodium sulfate and sodium carbonate; adding 150ml of water into the filter cake 2 for 2 times, and cleaning the residual sodium salt in the filter cake; adding 2.5ml of sulfuric acid into the mixed solution, adjusting the pH of the mixed solution to 6.5, and concentrating to obtain sodium sulfate crystals with the purity of 98.5%.
Acidifying with hydrochloric acid: adding 150ml of water into the filter cake 2, uniformly stirring, adding 10ml of hydrochloric acid to dissolve the alkaline precipitate in the filter cake 2, and filtering to obtain 26g of calcium fluoride and calcium chloride solution (containing a small amount of impurities); adding 22g of calcium hydroxide into the calcium chloride solution, adjusting the pH value of the solution to about 8, and filtering to obtain a pure calcium chloride solution, wherein the content of calcium chloride is 28%; 150ml of water is added to the calcium fluoride in 2 portions to wash the residual acidic calcium chloride solution in the calcium fluoride.
Drying and crushing: and (3) drying the treated calcium fluoride in an oven at 105 ℃, and crushing by using a crusher to obtain 11g of powdery calcium fluoride product, wherein the purity of the calcium fluoride is 92%.
Example 3
In the embodiment, calcium fluoride sludge generated in the photovoltaic industry is used as a raw material, the purity of calcium fluoride in raw sludge is 37.03%, and the calcium fluoride is treated according to the experimental method provided by the invention, and the specific steps are as follows.
Pulping and dissolving: 100g of calcium fluoride sludge is weighed and placed in a beaker, 200ml of water is added, and the mixture is heated and stirred for 30min at 60 ℃ to obtain uniformly dispersed solid-liquid mixed liquid.
Removing silicon by using caustic soda: adding 8g of sodium hydroxide into the solid-liquid mixed solution, stirring and reacting for 2 hours to completely convert silicon dioxide in the sludge into sodium silicate, and filtering to obtain a filter cake 1 and a sodium silicate solution; 200ml of water were added in 2 portions to the filter cake 1, washing the residual sodium salt in the filter cake.
Calcium salt conversion: adding 200ml of water into the filter cake 1, uniformly stirring, adding 2g of sodium carbonate to convert calcium sulfate in the filter cake 1 into calcium carbonate, stirring for reacting for 2 hours, and filtering to obtain a filter cake 2 and a mixed solution of sodium sulfate and sodium carbonate; adding 200ml of water into the filter cake 2 for 2 times, and cleaning residual sodium salt in the filter cake; and adding 2ml of sulfuric acid into the mixed solution, adjusting the pH value of the mixed solution to 7, and concentrating to obtain sodium sulfate crystals, wherein the purity of the sodium sulfate is 98.5%.
Acidifying with hydrochloric acid: adding 200ml of water into the filter cake 2, uniformly stirring, adding 10ml of hydrochloric acid to dissolve the alkaline precipitate in the filter cake 2, and filtering to obtain 26g of calcium fluoride and calcium chloride solution (containing a small amount of impurities); adding 25g of calcium hydroxide into the calcium chloride solution, adjusting the pH value of the solution to 8.5, and filtering to obtain a pure calcium chloride solution, wherein the content of calcium chloride is 28%; 150ml of water is added to the calcium fluoride in 2 portions to wash the residual acidic calcium chloride solution in the calcium fluoride.
Drying and crushing: and (3) drying the treated calcium fluoride in an oven at 105 ℃, and crushing by using a crusher to obtain 11g of powdery calcium fluoride product, wherein the purity of the calcium fluoride is 92%.
Claims (5)
1. A method for extracting pure calcium fluoride from calcium fluoride sludge is characterized by comprising the following steps:
1) pulping and dissolving: adding water into calcium fluoride sludge, heating and stirring to ensure that the sludge is uniformly dispersed to obtain a solid-liquid mixed solution; the mass ratio of the calcium fluoride sludge to the water is 1: 1-1: 2;
2) removing silicon by using caustic soda: adding caustic soda flakes into the solid-liquid mixed solution prepared in the step (1), stirring to convert silicon dioxide in the sludge into sodium silicate, and filtering to obtain a filter cake A and a solution A; the molar ratio of the addition amount of the caustic soda flakes to the content of silicon dioxide in the calcium fluoride sludge is 2:1, and the stirring time is 2 hours;
3) calcium salt conversion: mixing the filter cake A with water, uniformly stirring, adding sodium carbonate to convert calcium sulfate in the filter cake A into calcium carbonate, reacting, and filtering to obtain a filter cake B and a solution B; the solution B is a mixed solution of sodium carbonate and sodium sulfate, and sulfuric acid is added into the solution B to adjust the pH value to 6-7, so that a sodium sulfate solution is obtained; washing the filter cake B for multiple times;
4) acidifying with hydrochloric acid: mixing the filter cake B with water, uniformly stirring, adding hydrochloric acid to dissolve the alkaline precipitate in the filter cake B, and filtering to obtain calcium fluoride and a solution C; the solution C is a mixed solution containing calcium chloride, ferric chloride and aluminum chloride, calcium hydroxide is added into the solution C, the pH value of the solution is adjusted to 7.5-8.5, and the solution C is filtered to obtain a calcium chloride solution; washing the calcium fluoride with water for multiple times; the molar ratio of the consumption of the hydrochloric acid to the content of calcium in the calcium fluoride sludge is 2:1, and the stirring reaction time is 1 h;
5) drying and crushing: and (3) drying the acidified calcium fluoride in a 105 ℃ oven, and crushing the calcium fluoride by a crusher to obtain a pure powdery calcium fluoride product.
2. The method according to claim 1, wherein the heating temperature in the step (1) is 50-60 ℃ to accelerate the dissolution of the sludge.
3. The method according to claim 1, wherein the solution A in the step (2) is a sodium silicate solution; and washing the filter cake A with water for multiple times.
4. The method according to claim 1, wherein the molar ratio of the sodium carbonate added in the step (3) to the sulfate radical content in the sludge is 1.5:1, and the stirring reaction time is 2 hours.
5. The method as claimed in claim 1, wherein the purity of calcium fluoride in the pure calcium fluoride product is not less than 85%, the purity of chloride is not more than 0.01%, and P is2O5Calculated as phosphate, is less than or equal to 0.01 percent by weight of Fe2O3Iron is less than or equal to 0.1 percent calculated as Al2O3Calculated aluminum is less than or equal to 0.1 percent.
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110790295B (en) * | 2019-12-11 | 2022-05-10 | 合肥工业大学 | Method for preparing high-purity calcium fluoride from calcium fluoride sludge |
| CN111392754B (en) * | 2020-04-21 | 2022-05-03 | 深圳市考拉生态科技有限公司 | Method and equipment for purifying calcium chloride from fluorine-containing solid waste |
| CN111377474B (en) * | 2020-04-21 | 2022-05-17 | 深圳市考拉生态科技有限公司 | Method and equipment for purifying calcium fluoride from carbonate-removed fluorine-containing solid waste |
| CN111661864A (en) * | 2020-07-21 | 2020-09-15 | 四川省乐山锐丰冶金有限公司 | Method for preparing high-purity calcium fluoride by using fluorine-containing wastewater |
| CN111994937B (en) * | 2020-08-31 | 2023-11-03 | 苏州中材非金属矿工业设计研究院有限公司 | Method for recycling calcium fluoride from fluorine-containing sludge |
| CN113371749A (en) * | 2021-06-10 | 2021-09-10 | 西安吉利电子化工有限公司 | Method for treating calcium-containing sludge in semiconductor industry |
| CN113428886A (en) * | 2021-07-21 | 2021-09-24 | 西安吉利电子化工有限公司 | Method for producing high-purity calcium fluoride and concentrating waste hydrochloric acid by using waste acid |
| CN113683113A (en) * | 2021-07-21 | 2021-11-23 | 嘉峪关宏晟电热有限责任公司 | Process for purifying calcium fluoride from fluorite ore subjected to flotation |
| CN115072758A (en) * | 2022-07-15 | 2022-09-20 | 江苏省环境工程技术有限公司 | Method for extracting calcium fluoride from fluorine-containing sludge |
| CN118598447A (en) * | 2024-08-01 | 2024-09-06 | 浙江沃乐科技有限公司 | Treatment method and system for fluorine-containing sludge |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103232053A (en) * | 2013-05-17 | 2013-08-07 | 北方民族大学 | Method for producing calcium fluoride by bottom sludge generated during treatment of industrial fluoride-containing wastewater |
| CN103241758A (en) * | 2013-05-17 | 2013-08-14 | 崔岷 | Method of producing calcium fluoride through bottom mud generated by fluoride waste |
| CN105601066A (en) * | 2016-03-18 | 2016-05-25 | 盐城工学院 | Method for refining calcium fluoride from fluorine-containing sludge |
| CN107235502A (en) * | 2017-08-10 | 2017-10-10 | 衢州市鼎盛化工科技有限公司 | The method that calcirm-fluoride finished product is prepared using calcium fluoride containing sludge |
| CN108358231A (en) * | 2017-01-26 | 2018-08-03 | 新岛世纪（北京）新型材料技术有限公司 | A method of recycling fluorine resource from solar cell or glass thinning industry fluorine-containing sludge |
-
2019
- 2019-03-22 CN CN201910220579.5A patent/CN109775743B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103232053A (en) * | 2013-05-17 | 2013-08-07 | 北方民族大学 | Method for producing calcium fluoride by bottom sludge generated during treatment of industrial fluoride-containing wastewater |
| CN103241758A (en) * | 2013-05-17 | 2013-08-14 | 崔岷 | Method of producing calcium fluoride through bottom mud generated by fluoride waste |
| CN105601066A (en) * | 2016-03-18 | 2016-05-25 | 盐城工学院 | Method for refining calcium fluoride from fluorine-containing sludge |
| CN108358231A (en) * | 2017-01-26 | 2018-08-03 | 新岛世纪（北京）新型材料技术有限公司 | A method of recycling fluorine resource from solar cell or glass thinning industry fluorine-containing sludge |
| CN107235502A (en) * | 2017-08-10 | 2017-10-10 | 衢州市鼎盛化工科技有限公司 | The method that calcirm-fluoride finished product is prepared using calcium fluoride containing sludge |
Non-Patent Citations (1)
| Title |
|---|
| 从含氟底泥中提取氟化钙的研究;谢明等;《无机盐工业》;20141031;第46卷;第65-66页 * |
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