Method for producing polycrystalline silicon by utilizing sodium fluosilicate byproduct of phosphate fertilizer

A technology of sodium fluorosilicate and by-products, which is applied in the field of polysilicon production, can solve problems such as non-compliance with green development, environmental pollution, and reduced conversion rate of raw materials, and achieve the effects of saving raw materials, low impurity content, and reducing production costs

Active Publication Date: 2012-05-30
DO FLUORIDE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the silicon tetrachloride ( SIC14 ) produced in the production process is treated as a by-product, it will lead to a decrease in the conversion rate of raw materials, and at the same time pollute the environment, which does not meet the requirements of green development

Method used

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  • Method for producing polycrystalline silicon by utilizing sodium fluosilicate byproduct of phosphate fertilizer
  • Method for producing polycrystalline silicon by utilizing sodium fluosilicate byproduct of phosphate fertilizer
  • Method for producing polycrystalline silicon by utilizing sodium fluosilicate byproduct of phosphate fertilizer

Examples

Experimental program
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Effect test

Embodiment 1

[0026] The production method of this embodiment is as follows:

[0027] (1) Using clay, industrial salt, and hydrochloric acid as raw materials, leaching at 70℃ for 0.5h according to the ratio of Na / Al=0.95, and then filtering, the filtrate reacts with hydrofluoric acid to produce sodium tetrafluoroaluminum, and the mother liquor is returned ;

[0028] (2) The above-prepared sodium tetrafluoroaluminum and hydrogen are reacted at 600°C under the action of a palladium catalyst to produce sodium tetrahydro-aluminum according to the theoretical ratio;

[0029] (3) At the same time, pyrolyze sodium fluorosilicate, a byproduct of phosphate fertilizer required by the theoretical ratio, at 700°C to generate sodium fluoride and silicon tetrafluoride gas;

[0030] (4) The mass ratio of 2:1 sodium tetrahydroaluminum and silicon tetrafluoride are reacted in a mixed solvent of 60°C, glycol dimethyl ether and toluene to obtain silane and sodium tetrafluoroaluminum, sodium tetrafluoroaluminum Recyc...

Embodiment 2

[0035] The production method of this embodiment is as follows:

[0036] (1) Using clay, industrial salt, and hydrochloric acid as raw materials, leaching at 80℃ for 1 hour according to the ratio of Na / Al=1.0, then filtering, the filtrate reacts with hydrofluoric acid to produce sodium tetrafluoroaluminum, and the mother liquor is returned ;

[0037] (2) The above-prepared sodium tetrafluoroaluminum and hydrogen are reacted at 400°C under the action of a nickel catalyst according to the theoretical ratio to generate sodium tetrahydroaluminum;

[0038] (3) At the same time, pyrolyze sodium fluorosilicate, a byproduct of phosphate fertilizer required by the theoretical ratio, at 770°C to generate sodium fluoride and silicon tetrafluoride gas;

[0039] (4) The reaction of sodium tetrahydroaluminum sodium and silicon tetrafluoride with a mass ratio of 3:1 in a mixed solvent of 80°C, glycol dimethyl ether and toluene to obtain silane, sodium tetrafluoroaluminum, and tetrafluoroaluminum Sod...

Embodiment 3

[0044] The production method of this embodiment is as follows:

[0045] (1) Using clay, industrial salt, and hydrochloric acid as raw materials, leaching at 90°C for 1 hour according to the ratio of Na / Al=1.1, then filtering, the filtrate reacts with hydrofluoric acid to produce sodium tetrafluoroaluminum, and the mother liquor is returned ;

[0046] (2) The above-prepared sodium tetrafluoroaluminum and hydrogen are reacted to form sodium tetrahydro-aluminum at 200°C under the action of a nickel catalyst according to the theoretical ratio;

[0047] (3) At the same time, pyrolyze sodium fluorosilicate, a byproduct of phosphate fertilizer required by the theoretical ratio, at 900°C to generate sodium fluoride and silicon tetrafluoride gas;

[0048] (4) The reaction of sodium tetrahydroaluminum sodium and silicon tetrafluoride with a mass ratio of 4:1 in a mixed solvent of 100°C, glycol dimethyl ether and toluene to obtain silane, sodium tetrafluoroaluminum, and aluminum tetrafluoride S...

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Abstract

The invention relates to a method for producing polycrystalline silicon by utilizing a sodium fluosilicate byproduct of a phosphate fertilizer. The sodium fluosilicate byproduct of the phosphate fertilizer is subjected to paralysis to form silicon tetrafluoride and sodium aluminum hydride, which serve as raw materials to prepare silane, and the silane is cracked to form the polycrystalline silicon and hydrogen, wherein the hydrogen is circulated and used for hydrogenating sodium aluminum tetrafluoride. A hydrofluoric acid byproduct generated in the reaction process is used for producing fluoride salt products. In the method for producing the polycrystalline silicon, the byproduct is taken as a raw material, the price is low, the process is simple, easy to operate, environment-friendly andenergy-saving; the produced polycrystalline silicon has low impurity content and high purity; in addition, the hydrofluoric acid byproduct in the production can be used for producing the fluoride salt products, so that the production cost is further reduced, and the method has better economic, social and environmental benefits.

Description

technical field [0001] The invention relates to a method for producing polysilicon by using sodium fluorosilicate, a by-product of phosphate fertilizer. 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] The polysilicon production process is mainly the improved Siemens method. This process is mature and the yield is high. But due to SiCl 4 The threshold of hydrogen reduction technology is relatively high, which relatively increases the production cost. If the silicon tetrachloride (SIC1) produced in the production process 4 ) as a by-product will reduce the conversion rate of raw materials and pollute the environment at the same time, which does not meet the requirements of green and environmental ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/029C01B33/021
CPCC01B33/029C01B33/021C01B33/04C01B33/043C01B33/027
Inventor 李世江侯红军杨华春于贺华薛旭金刘海霞孙永明王慧施秀华
Owner DO FLUORIDE CHEM CO LTD
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