A method for preparing high-purity calcium fluoride and calcium chloride by using fluorine-chlorine mixed acid separated from dirty acid

A high-purity, calcium chloride technology, applied in the direction of calcium/strontium/barium chloride, calcium/strontium/barium fluoride, calcium/strontium/barium halide, etc., can solve only hazardous waste and product utilization side effects Low value and other problems, to achieve the effect of easy control of steps, simple process and low processing cost

Active Publication Date: 2021-09-21
CHANGSHA SCI ENVIRONMENTAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The secondary value of product utilization is relatively low, and sometimes it can only be treated as hazardous waste and general solid waste. In order to increase the added value of the product, it is urgent to develop a method for treating the above mixed acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The fluorine-chlorine mixed acid produced in the process of sewage acid treatment in a smelter was used for testing. The main components of the water quality of the fluorine-chlorine mixed acid are shown in Table 1.

[0027] Table 1 Fluorochlorine mixed acid water quality (mg / L)

[0028] element F -

Cl -

H +

concentration 13256.23 10267.87 987.56

[0029] The specific processing steps are:

[0030] (1) Get 50g of analytically pure calcium hydroxide as a neutralizing agent, slowly add fluorine-chlorine mixed acid to the neutralizing agent to react, stir during the addition process, detect the pH value of the reaction process, stop adding the mixed acid when the pH value slowly drops to 1.5, Stirring was continued for 20 minutes, the pH rose somewhat, and the pH at the end point of the first-stage neutralization was 1.7. At this time, 1420 mL of mixed acid was consumed, and 61.64 g of the first-stage neutralization slag was obtained by fi...

Embodiment 2

[0035] The fluorine-chlorine mixed acid produced in the sewage acid treatment process in a smelter was used for testing. The main components of the fluorine-chlorine mixed acid water quality are shown in Table 2.

[0036] Table 2 Fluorochlorine mixed acid water quality (mg / L)

[0037] element F -

Cl -

H +

concentration 14367.40 35263.90 1750.45

[0038] The specific processing steps are:

[0039] (1) Get 100g of analytically pure calcium hydroxide as a neutralizing agent, slowly add fluorine-chlorine mixed acid to the neutralizing agent to react, stir during the addition process, detect the pH value of the reaction process, stop adding the mixed acid when the pH value slowly drops to 1.4, Stirring was continued for 20 minutes, the pH rose somewhat, and the pH at the end point of the first-stage neutralization was 1.7. At this time, 1620 mL of mixed acid was consumed, and 76.46 g of the first-stage neutralization slag was obtained by filtration...

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PUM

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Abstract

The invention discloses a method for preparing high-purity calcium fluoride and calcium chloride by using fluorine-chlorine mixed acid separated from polluted acid, which comprises the following steps: (1) adding fluorine-chlorine mixed acid to a neutralizer to carry out a stage of neutralization , control the pH value of one section of neutralization end point to 1.5-3, obtain a section of neutralization slag and a section of neutralization filtrate through solid-liquid separation; (2) mix a section of neutralization slag and water to obtain an aqueous solution, then add a flocculant to settle and filter to obtain a high Pure calcium fluoride product and cleaning solution; (3) Collect the mixed solution obtained from the first-stage neutralization filtrate and cleaning solution, add a neutralizer to carry out second-stage neutralization and deep defluorination, and separate solid-liquid to obtain calcium chloride-rich solution and second-stage neutralization solution. and slag; (4) the calcium chloride-rich solution is subjected to cyclic evaporation crystallization and solid-liquid separation to obtain a high-purity calcium chloride product. The invention can recycle the fluorine-chloride mixed acid separated from the polluted acid step by step, and the obtained high-purity calcium fluoride has a purity of ≥99%, and the high-purity calcium chloride has a purity of ≥99%, both of which meet the national Class I standard.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and environmental protection, and in particular relates to a method for preparing high-purity calcium fluoride and calcium chloride by using fluorine-chlorine mixed acid separated from dirty acid. Background technique [0002] The polluted acid wastewater produced by the acid production of non-ferrous smelting flue gas has a high concentration of arsenic, which is the most harmful, and contains relatively high levels of fluorine and chlorine. The arsenic in polluted acid wastewater is mainly arsenous acid and is the most difficult to treat. Therefore, the treatment process of domestic polluted acid wastewater is mainly aimed at removing arsenic. At present, there are mainly neutralization method, vulcanization method-neutralization method, neutralization-iron salt co-precipitation method in domestic treatment of polluted acid wastewater. For wastewater with extremely high arsenic concentration...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F11/22C01F11/32C01F11/24
CPCC01F11/22C01F11/24C01F11/32C01P2006/80
Inventor 蒋国民郑九林高伟荣陶镇廖圆岑家山胡明
Owner CHANGSHA SCI ENVIRONMENTAL TECH
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