Method for recycling cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources

A technology of sodium sulfate and calcium fluoride, which is applied in the preparation of calcium carbonate/strontium/barium, aluminum fluoride, sulfate/bisulfate, etc., can solve the problems of high toxicity of hydrogen fluoride gas and complicated process conditions, and achieve conversion rate The effect of high recovery rate, easy large-scale production, and easy control of process conditions

Active Publication Date: 2017-01-04
盛隆资源再生(无锡)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method obtains hydrogen fluoride with high purity and high product quality, but the process conditions are complicated, and hydrogen fluoride gas itself is highly toxic

Method used

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  • Method for recycling cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources

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Effect test

Embodiment 1

[0027] The applicant provides a method for reclaiming cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources, the specific steps are as follows:

[0028] (1) add sulfuric acid in calcium fluoride sludge 1000g, adjust its pH=2, when using sulfuric acid to acidify sludge, the time is 1.5h; Calcium that exists in the form of calcium hydroxide and calcium carbonate is converted into calcium sulfate to obtain solution A.

[0029] (2) Add 200g of sodium aluminate solid in solution A, and carry out stirring and leaching to convert calcium fluoride into fluoaluminic acid and calcium sulfate precipitation S1 and solution B;

[0030] (3) Sodium carbonate is added in solution B to make it pH=0.1, and 70g of sodium sulfate is added to promote the precipitation of sodium fluoroaluminate completely, and the stirring time is 1h to obtain 100g of cryolite and solution C; the amount of sodium carbonate is 1.3 of calcium sulfate times.

[0031] (4) Add 100mL 20w...

Embodiment 2

[0035] The applicant provides a method for reclaiming cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources, the specific steps are as follows:

[0036] (1) Add sulfuric acid to 1000 g of calcium fluoride sludge to adjust its pH=1. When sulfuric acid is used to acidify the sludge, the time is 1 hour; the calcium existing in the form of calcium hydroxide and calcium carbonate in the sludge is converted into sulfuric acid Calcium, to obtain solution A.

[0037] (2) Add 285g of sodium aluminate solid in solution A, and carry out stirring and leaching to convert calcium fluoride into fluoaluminic acid and calcium sulfate precipitation S1 and solution B;

[0038] (3) Sodium carbonate is added in solution B to make it pH=1, and 30g of sodium sulfate is added to impel the precipitation of sodium fluoroaluminate completely, and the stirring time is 1.5h to obtain 100g of cryolite and solution C; the amount of sodium carbonate is that of calcium sulfate ...

Embodiment 3

[0043] The applicant provides a method for reclaiming cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources, the specific steps are as follows:

[0044] (1) Add sulfuric acid to 1000 g of calcium fluoride sludge to adjust its pH=3. When using sulfuric acid to acidify the sludge, the time is 2 hours; the calcium existing in the form of calcium hydroxide and calcium carbonate in the sludge is converted into sulfuric acid Calcium, to obtain solution A.

[0045] (2) Add 500g of sodium aluminate solid in solution A, and carry out stirring and leaching to convert calcium fluoride into fluoaluminic acid and calcium sulfate precipitation S1 and solution B;

[0046] (3) Add sodium carbonate to solution B to make it pH=2, and add 50g of sodium sulfate to promote the complete precipitation of sodium fluoroaluminate, and stir for 2 hours to obtain 100g of cryolite and solution C; the amount of sodium carbonate is 1.5 of calcium sulfate times.

[0047] (4)...

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Abstract

The invention provides a method for recycling cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources. The method includes the following specific steps that 1, sulfuric acid is added into calcium fluoride sludge, the pH is adjusted to range from 1 to 3, calcium, existing in the form of calcium hydroxide and calcium carbonate, in the sludge is converted into calcium sulfate, and a solution A is obtained; 2, sodium aluminate solids are added into the solution A, stirring and leaching are carried out, and calcium fluoride is converted into fluoaluminic acid, calcium sulfate precipitates S1 and a solution B; 3, sodium carbonate is added into the solution B, the pH ranges from 0.1 to 2, sodium sulfate is replenished, the calcium sulfate is promoted to be completely precipitated, and cryolite and a solution C are obtained; 4, a sodium bicarbonate solution is added into the precipitates S1 for treatment, and calcium carbonate and a solution D are obtained through filtering; 5, the solution C and the solution D are mixed and subjected to evaporative crystallization to obtain sodium sulfate. The method has the advantages that process conditions are easy to control, and large-scale production is easy, and calcium fluoride sludge recycling can be achieved.

Description

technical field [0001] The application relates to the field of calcium fluoride sludge treatment, in particular to a method for recovering cryolite, calcium carbonate and sodium sulfate from calcium fluoride sludge resources. Background technique [0002] Fluorine is indispensable in today's industrial production due to its unique chemical properties. Fluorine chemical wastewater is often treated by adding alkaline substances such as lime and carbide slag to neutralize precipitation and flocculation, and often mixes several streams of wastewater generated by different processes, which increases the difficulty of wastewater treatment and the complexity of sludge. It is mainly reflected in the complex composition of calcium fluoride sludge, containing calcium carbonate, calcium hydroxide, etc. Commonly used PAC flocculants will introduce aluminum metal and a small amount of iron metal. Therefore, the treatment of calcium fluoride sludge has always been the focus of people's a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/54C01F11/18C01D5/10
CPCC01D5/10C01F7/54C01F11/18
Inventor 万园园冯龙海高国峰郎超
Owner 盛隆资源再生(无锡)有限公司
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