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Method for comprehensively utilizing chemical byproduct single cryolite

A single cryolite and by-product technology is applied in the field of comprehensive utilization of chemical by-product single cryolite, can solve the problems of no treatment method, environmental pollution, waste of resources, etc., achieves huge environmental protection and social benefits, low price, The effect of high utilization of raw materials

Active Publication Date: 2011-06-29
BAIYIN ZHONGTIAN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, every ton of polysilicon produced by the inorganic method must produce at least 4.5 tons of monocryolite with high impurities. Its main components are sodium tetrafluoroaluminate, about 10% aluminum element, and about 1% silicon compound. The method of burying causes environmental pollution and waste of resources. So far, there is no more suitable treatment method

Method used

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  • Method for comprehensively utilizing chemical byproduct single cryolite
  • Method for comprehensively utilizing chemical byproduct single cryolite
  • Method for comprehensively utilizing chemical byproduct single cryolite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1. Using polycrystalline silicon by-product monocryolite and sodium hydroxide solution as raw materials, according to the mass ratio M NaOH :M 单冰晶石 =2.0 React at 60°C for 1 hour to generate hydrogen and sodium aluminate slurry, and recover the hydrogen;

[0021] 2, the mixed slurry prepared in step 1 and hydrofluoric acid are mixed according to the proportion V 混合料浆 :V 氢氟酸 =1︰1 react at 20°C for 1.5h to prepare cryolite slurry;

[0022] 3. Filtrating and washing the cryolite slurry in step 2 to obtain a cryolite ointment for aluminum and a mother liquor, which is used to synthesize other fluoride salts;

[0023] 4. Dry the cryolite ointment for aluminum smelting in step 3 to obtain cryolite for aluminum.

Embodiment 2

[0025] 1. Using polysilicon by-product monocryolite and sodium hydroxide solution as raw materials, according to the mass ratio M NaOH :M 单冰晶石 =3.0 React at 70°C for 3 hours to generate hydrogen and sodium aluminate slurry, and recover the hydrogen;

[0026] 2, the mixed slurry prepared in step 1 and hydrofluoric acid are mixed according to the proportion V 混合料浆 :V 氢氟酸 =2︰1 React at 30°C for 3 hours to prepare cryolite slurry;

[0027] 3. Filtrating, washing and separating the cryolite slurry in step 2 to obtain a cryolite ointment for aluminum and a mother liquor, which is used to synthesize other fluoride salts;

[0028] 4. Dry the aluminum cryolite ointment in step 3 to obtain aluminum cryolite.

Embodiment 3

[0030] 1. Using polysilicon by-product monocryolite and sodium hydroxide solution as raw materials, according to the mass ratio M NaOH :M 单冰晶石 =4.0 React at 100°C for 5 hours to generate hydrogen and sodium aluminate slurry, and recover the hydrogen;

[0031] 2, the mixed slurry prepared in step 1 and hydrofluoric acid are mixed according to the proportion V 混合料浆 :V 氢氟酸 =3︰1 react at 45°C for 4.5h to prepare cryolite slurry;

[0032] 3. Filtrating and washing the cryolite slurry in step 2 to obtain a cryolite ointment for aluminum and a mother liquor, which is used to synthesize other fluoride salts;

[0033] 4. Dry the aluminum cryolite ointment in step 3 to obtain aluminum cryolite.

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Abstract

The invention belongs to the technical field of polysilicon production, in particular to a method for comprehensively utilizing a chemical byproduct single cryolite during production of polysilicon. The method comprises the following steps of: reacting the single cryolite with sodium hydroxide solution to generate hydrogen and sodium aluminate slurry; and reacting the sodium aluminate slurry withhydrofluoric acid to prepare cryolite for aluminum, wherein the byproduct, namely hydrogen in the reaction process is purified and recovered to serve as a byproduct; and mother liquid is used for producing other fluoride products, or being neutralized by adding lime and then being discharged. The byproduct, namely single cryolite, of polysilicon is used for producing cryolite for aluminum, so rawmaterials are readily available, cost is low and the utilization ratio of the raw materials is high; the produced cryolite for aluminum has low impurity content and meets national standard; and wasteis changed into treasure, which accords with production ideas of comprehensive utilization of resources, energy conservation and environmental protection.

Description

technical field [0001] The invention belongs to the technical field of polysilicon production, and in particular relates to a comprehensive utilization method of monocryolite, a chemical by-product in polysilicon production. Background technique [0002] At present, crystalline silicon materials (including polycrystalline silicon and monocrystalline silicon) are the most important photovoltaic materials, with a market share of more than 90%, and will still be the mainstream material of solar cells for a long period of time in the future. [0003] Polysilicon production processes include improved Siemens method, magnesium silicide method, REC method, silane method and other synthesis processes. Compared with various processes, inorganic production processes such as the silane method have the characteristics of easy availability of raw materials, low energy consumption, low cost, and low environmental protection pressure, and are the future development direction of polysilicon...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/54C01B3/08
CPCY02E60/36
Inventor 侯红军杨华春高月陈以春于贺华师玉萍孙永明王建萍刘海庆
Owner BAIYIN ZHONGTIAN CHEM
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