Rare earth molten salt electrolysis fluorine-containing wastewater treatment method

A technology for molten salt electrolysis and wastewater treatment, which is used in water/sewage treatment, neutralized water/sewage treatment, and multi-stage water/sewage treatment. problems, to achieve the effect of saving resources, clarifying water quality, and avoiding sludge bulking

Inactive Publication Date: 2021-06-25
FUJIAN CHANGJIANG GOLDEN DRAGON RARE EARTH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Rare earth molten salt electrolysis fluorine-containing wastewater, the fluorine content is about 3000-20000mg / L, there are two technical problems in the prior art: one is the drawback that the lime precipitation defluorination process cannot meet the discharge standard of 8 mg / L; the other is industrial production Pipe plugging often occurs in production, which affects production and increases costs

Method used

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  • Rare earth molten salt electrolysis fluorine-containing wastewater treatment method
  • Rare earth molten salt electrolysis fluorine-containing wastewater treatment method
  • Rare earth molten salt electrolysis fluorine-containing wastewater treatment method

Examples

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Effect test

Embodiment 1

[0041] Fluorine-containing wastewater generated during the production process of the factory: fluoride ion concentration 7681mg / L, pH=3. The daily wastewater treatment capacity is about 10 cubic meters, and the daily operation time is 10 hours. The specific steps of fluorine-containing wastewater treatment are as follows:

[0042] Step 1: Collect fluorine-containing wastewater and send it to a settling tank (capacity of 8 cubic meters) to preliminarily settle the suspended solids in the wastewater and clarify the water quality.

[0043] Step 2: Send the effluent from the sedimentation tank to the pH value regulator, add calcium hydroxide solution and flake sodium hydroxide, the mass concentration of the added calcium hydroxide is 5g / L, add 25kg of caustic soda, add 25kg of calcium chloride solid, Compressed air is passed through the regulator for stirring, and the pressure of the compressed air is greater than 0.2MPa. In order to ensure the full reaction of fluoride ions and...

Embodiment 2

[0049] Fluorine-containing waste water generated during the production process of the factory: fluoride ion concentration 3010mg / L, pH=4.5. The daily wastewater treatment capacity is about 10 cubic meters, and the daily operation time is 10 hours. The specific steps of fluorine-containing wastewater treatment are as follows:

[0050] Step 1: Collect fluorine-containing wastewater and send it to a settling tank (capacity of 8 cubic meters) to preliminarily settle the suspended solids in the wastewater and clarify the water quality.

[0051] Step 2: Send the effluent from the sedimentation tank to the pH regulator, add calcium hydroxide solution and caustic soda, the mass concentration of the added calcium hydroxide is 5g / L, add 12kg caustic soda, and stir with compressed air in the regulator, compressed air The pressure is greater than 0.2Mpa to increase the solubility of calcium hydroxide and caustic soda, and the reaction time is 30-40min. Because the fluoride ion concentra...

Embodiment 3

[0057] Fluorine-containing wastewater generated during the production process of the factory: fluoride ion concentration 13265mg / L, pH=2. The daily waste water treatment capacity is about 10 cubic meters, and the daily operation time is 10 hours. The specific steps of fluorine-containing wastewater treatment are as follows:

[0058] Step 1: Collect fluorine-containing wastewater and send it to a settling tank (capacity of 8 cubic meters) to preliminarily settle the suspended solids in the wastewater and clarify the water quality.

[0059] Step 2: Send the effluent from the sedimentation tank to the pH regulator, add calcium hydroxide solution and caustic soda, the mass concentration of calcium hydroxide added is 8g / L, add caustic soda 25kg, and stir with compressed air in the regulator, compressed air The pressure is greater than 0.2MPa, and the reaction time is 30-40 minutes. Simultaneously, calcium chloride solid is added according to the molar ratio of fluoride ion to cal...

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Abstract

The invention relates to a rare earth molten salt electrolysis fluorine-containing wastewater treatment method, which adopts continuous operation of 'double calcium method + coagulation + flocculation + precipitation ', and can control the fluorine ion concentration of high-concentration fluorine-containing wastewater to be below 8mg / L. According to the method, on one hand, the problem of easy pipe blockage in industrial production is thoroughly solved, and continuous long-time operation can be realized; and on the other hand, the fluorine ion removal efficiency is further improved, and the treatment cost is reduced. The method has the advantages of simple process flow, high defluorination efficiency, low treatment cost and easiness in sludge sedimentation, and is particularly suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of rare earth materials, and relates to a method for treating waste water produced by electrolysis of rare earth molten salts, in particular to a process for treating high-concentration fluorine-containing waste water. Background technique [0002] Rare earth electrolysis uses rare earth fluoride as molten salt. During the electrolysis process, part of the fluoride will volatilize with the electrolysis flue gas. After the dust is removed by the dust removal system, the flue gas enters the spray tower, and the fluorine-containing waste gas is washed by water washing and alkali washing. Dissolved into hydrogen fluoride aqueous solution or sodium fluoride aqueous solution, and enter the wastewater treatment station, part of the unorganized discharge of fluoride will be washed by rainwater into the initial rainwater collection pond of the factory area, and finally enter the wastewater treatment station, the fluor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F101/14
CPCC02F9/00C02F2001/007C02F1/66C02F1/583C02F1/5236C02F1/56C02F2101/14
Inventor 李亮亮张永健崔红岩钟希辉
Owner FUJIAN CHANGJIANG GOLDEN DRAGON RARE EARTH CO LTD
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