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Recycling method of polycrystalline silicon side product silicon tetrachloride

A technology of silicon tetrachloride and by-products, which is applied in the field of recycling silicon tetrachloride, a by-product of polysilicon, can solve problems such as hazards and environmental pollution of silicon tetrachloride, and achieve reduced production costs, huge economic benefits and social benefits , the effect of reducing dosage

Active Publication Date: 2013-03-20
SICHUAN YINBANG SILICON IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It not only improves the economic utilization value of silicon tetrachloride, but also solves the environmental pollution and hazards of silicon tetrachloride, and can produce huge economic and environmental benefits

Method used

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  • Recycling method of polycrystalline silicon side product silicon tetrachloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Example 1 Preparation of Ethoxysilane-40 by Polysilicon By-product Silicon Tetrachloride

[0052] A small amount of edible alcohol is pre-added in the packed reaction tower, and silicon tetrachloride and edible alcohol (calculated as pure ethanol) are passed into the reaction tower at the same time in a molar ratio of 1.0:2.9, and the temperature of the tower tank is controlled to be 25°C. The reaction is carried out to obtain a reaction material containing ethoxysilane oligomers and hydrogen chloride. The hydrogen chloride gas generated by the reaction is absorbed by water in a graphite absorber to obtain industrial hydrochloric acid.

[0053] Press the reaction material into the acid catcher, slowly heat it to the bottom temperature of 110°C, distill off unreacted raw materials and part of hydrogen chloride; 0.45 times the number of moles, heated to a temperature of 110°C at the bottom of the kettle, and distilled to remove the acid catching agent and hydrogen chlori...

Embodiment 2

[0059] The reclaiming agent that water and embodiment 1 reclaims (the unreacted raw material that reclaims and catches acid agent), in molar ratio is 1.0: 4.8 (in terms of water and pure ethanol) to pass into ethanol batching tank and obtain ethanol mixed solution, in A small amount of ethanol mixed liquid is pre-added into the packing reaction tower, and then silicon tetrachloride, water and recovering agent are simultaneously passed into the reaction tower at a molar ratio of 1.0:0.6:2.9. Other conditions are with embodiment 1.

[0060] The product purity is 99%, and the yield is over 90%.

[0061] Each batch of finished ethoxysilane-40 is a colorless transparent liquid, acidity (HCl) 2 / s, the content of silicon in ethoxysilane is SiO 2 Calculated as 38 to 42%.

Embodiment 3

[0063] Water and the recovering agent (i.e. reclaimed unreacted raw materials and acid catcher) reclaimed above are passed into the ethanol batching tank in a molar ratio of 1.0: 3.0 (in terms of water and pure ethanol) to obtain the ethanol mixture, and in the packed reaction tower Add a small amount of ethanol mixed solution in advance, and then pass silicon tetrachloride, water and recovering agent into the reaction tower at the same time with a molar ratio of 1.0:0.8:2.4. Anhydrous ethanol is used as an acid catching agent. Other conditions are with embodiment 1.

[0064] The product purity is 99%, and the yield is over 90%.

[0065] Each batch of finished ethoxysilane-40 is a colorless transparent liquid, acidity (HCl) 2 / s, the content of silicon in ethoxysilane is SiO 2 Calculated as 38 to 42%.

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Abstract

The invention relates to a recycling method of polycrystalline silicon side product silicon tetrachloride, which belongs to the technical field of polycrystalline silicon production. The technical scheme provided by the invention comprises the following steps of: putting silicon tetrachloride, water and low-grade fatty alcohol ROH according to a certain mixing ratio to carry out chemical reactionso that a reaction material containing alkoxy silane low polymer and hydrogen chloride is obtained; adding an acid expelling agent to remove hydrogen chloride; adding an alkaline substance to neutralize the reaction material until the pH value is 6-8; and decoloring and filtering to obtain a finished product alkoxy silane low polymer. The method provided by the invention provides a new way for recycling the polycrystalline silicon side product silicon tetrachloride and has the advantages of large production capacity, less equipment investment, convenience for controlling, no pollution to the environment and benefit of industrial production. In addition, the alkoxy silane low polymer is produced in one step by using water containing low-grade fatty alcohol instead of anhydrous low-grade fatty alcohol so that the operation step is reduced and the production cost is further reduced.

Description

technical field [0001] The invention relates to a method for recycling silicon tetrachloride, a by-product of polysilicon, and belongs to the technical field of polysilicon production. Background technique [0002] Polysilicon is the main raw material of solar cells. With the rapid development of solar photovoltaic industry, the demand for polysilicon at home and abroad has grown rapidly, and the construction of polysilicon has set off an upsurge in China. At present, the production methods used by polysilicon enterprises are Siemens method, which will produce a large amount of silicon tetrachloride by-products, and an average of 15 tons of silicon tetrachloride will be produced for every ton of polysilicon produced. Silicon tetrachloride is a poisonous and harmful liquid with strong corrosiveness. If silicon tetrachloride is discharged or buried without treatment, it will seriously pollute the environment and make the discharge or burial place barren. With the continuous e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G77/18C08G77/06C08G77/34
Inventor 牟浩斌易家宝邹振
Owner SICHUAN YINBANG SILICON IND