Method for treating electrolytic waste residues and wastewater produced in electrolytic process nitrogen trifluoride production technology

A treatment method, nitrogen trifluoride technology, applied in water/sewage treatment, improvement of process efficiency, chemical instruments and methods, etc., to achieve recovery and comprehensive utilization, high purity, significant economic and environmental benefits

Inactive Publication Date: 2020-01-10
洛阳昊华气体科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved in the present invention is to provide a treatment method for electrolytic waste residue wastewater produced by the process of nitrogen trifluoride produced by electrolysis, waste utilization, and reduction of air pollution

Method used

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  • Method for treating electrolytic waste residues and wastewater produced in electrolytic process nitrogen trifluoride production technology
  • Method for treating electrolytic waste residues and wastewater produced in electrolytic process nitrogen trifluoride production technology

Examples

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Effect test

Embodiment 1

[0019] Add 300kg of electrolytic waste residue and 1 ton of fluorine-containing waste water produced during the dismantling of the electrolytic cell into the neutralization kettle, stir until fully dissolved, feed ammonia water with a mass concentration of 20% to 25%, and control the reaction temperature at 35°C 45° C., until the pH value of the reaction kettle solution reaches 3, stop feeding ammonia water to obtain an ammonium bifluoride solution with a mass concentration of 18%. Add 10 g of polyferric chloride to the ammonium bifluoride solution to precipitate nickel-containing by-products, flocculate and form precipitates, and centrifuge to separate nickel-containing by-products.

[0020] Mix the obtained ammonium bifluoride solution with a mass concentration of 18% and the crystallized ammonium bifluoride mother liquor, add it to a vacuum dehydration kettle, and conduct evaporation, concentration and dehydration under the conditions of -0.086~-0.096MPa, 65~75°C until the ...

Embodiment 2

[0024] Add 400kg of electrolytic waste slag and 1 ton of fluorine-containing wastewater generated during the dismantling process into the neutralization reactor, stir until fully dissolved, feed ammonia water with a mass concentration of 20% to 25%, and control the reaction temperature at 40°C 50 DEG C, until the pH value of the reactor solution reaches 2, stop feeding ammonia water to obtain a 22% ammonium bifluoride solution with a mass concentration. Add 10 g of iron polysilicate to the ammonium bifluoride solution to precipitate, flocculate and form precipitates by-products containing nickel, and centrifuge to separate the by-products containing nickel.

[0025] Mix the obtained ammonium bifluoride solution with a mass concentration of 22% and the crystallized ammonium bifluoride mother liquor, add it to a vacuum dehydration kettle, and conduct evaporation, concentration and dehydration under the conditions of -0.086~-0.096MPa, 65~75°C until the ammonium bifluoride The co...

Embodiment 3

[0029] Add 500kg of electrolytic waste slag and 1 ton of fluorine-containing waste water produced during the dismantling process into the neutralization reactor, stir until fully dissolved, feed ammonia water with a mass concentration of 20% to 25%, and control the reaction temperature at 20°C 35° C., until the pH value of the reaction kettle solution reaches 4, stop feeding ammonia water to obtain an ammonium bifluoride solution with a mass concentration of 26%. Add 10 g of polyferric sulfate to the ammonium bifluoride solution to precipitate nickel-containing by-products, flocculate and form precipitates, and centrifuge to separate nickel-containing by-products.

[0030] Mix the obtained ammonium bifluoride solution with a mass concentration of 26% and the crystallized ammonium bifluoride mother liquor, add it to a vacuum dehydration kettle, and conduct evaporation, concentration and dehydration under the conditions of -0.086~-0.096MPa, 65~75°C until the ammonium bifluoride ...

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Abstract

The invention discloses a method for treating electrolytic waste residues and wastewater produced in an electrolytic process nitrogen trifluoride production technology. The method comprises the following steps: (1) neutralizing the electrolytic waste residues and wastewater: adding the electrolytic waste residues and fluorine-containing wastewater generated by cleaning an electrolytic bath into aneutralizing kettle, performing stirring until full dissolving, introducing ammonia water, controlling the reaction temperature to 20-50 DEG C until the pH value of the solution in the reaction kettlereaches 2-5, and stopping the introduction of the ammonia water in order to obtain an aqueous ammonium bifluoride solution; (2) centrifugally separating a nickel-containing byproduct: adding a flocculating agent into the ammonium bifluoride solution to separate out and flocculate the nickel-containing byproduct and form a precipitate, and centrifugally separating the nickel-containing byproduct;(3) performing vacuum concentration: adding the ammonium bifluoride solution into a dehydration kettle, and carrying out evaporative concentrating dehydration under the conditions of -0.086 to -0.096Mpa and 65-75 DEG C until the mass concentration of ammonium bifluoride reaches 60-80%; and (4) performing cooling crystallization, centrifugal separation and drying. The method reduces environmentalpollution, realizes resource recycling and reduces the production cost.

Description

technical field [0001] The invention relates to the technical field of preparing nitrogen trifluoride by electrolysis, in particular to a method for treating electrolytic waste residue wastewater of nitrogen trifluoride by electrolysis. Background technique [0002] Nitrogen trifluoride is an electronic material developed in recent years. It is mostly used as an etchant for semiconductor materials such as polysilicon, silicon nitride, and tungsten silicide, especially for the etching of integrated circuit materials with a thickness of less than 1.5 μm; it can be used in integrated It can be used as a cleaning agent in the production of circuit boards and liquid crystal displays; as a fluorine source for hydrogen fluoride-fluorine gas high-energy chemical lasers, etc. [0003] During the preparation of nitrogen trifluoride by electrolysis, nickel is gradually dissolved as an anode, and deposited on the bottom of the electrolytic cell in the form of nickel fluoride and complex...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/10C01C1/16C22B7/00C22B23/00C01B21/083C02F101/16C02F101/14
CPCC01B21/0832C01C1/162C02F1/04C02F1/38C02F1/5236C02F1/5245C02F1/66C02F9/00C02F2101/14C02F2101/16C22B7/006C22B23/0453Y02P10/20
Inventor 高宝柱王娟魏磊杨亚琴陶茜刘锐
Owner 洛阳昊华气体科技有限公司
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