Treatment method of byproduct sulfate in process of producing solar grade polysilicon through silane method

A solar-grade, treatment-method technology that is applied to sulfate preparations, waste treatment, alkali metal carbonate, etc., and can solve the problems of fine-grained silica dust

Inactive Publication Date: 2010-09-15
杨更亮
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its advantages are high purity polysilicon products, suitable for zone melting growth of high-resistance single crystal silicon, silane decomposition conversion rate as high as 99%, less by-products, and disadvantages are more fine silicon dust

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Embodiment 1: direct double salt generation

[0020] In reactor, add by-product mixed sulfate 100.0g (material weight is made up of Na + , 8.7%; Al 3+ , 10.8%; SO 4 2- , 74.6%; F - , 0.1%; H + , 0.11%; the remainder is other impurities), adding 40.0Kg of preheated sodium hydroxide solution (1.0% by weight), fully reacting for 4 hours, and its pH value is 6.5. Dry to obtain 103.0 g of crude product of sodium aluminum sulfate. After aging, crystallization and drying, 100.5 g of sodium aluminum sulfate product was obtained.

Embodiment 2

[0021] Embodiment 2: direct double salt generation

[0022] In reactor, add by-product mixed sulfate material 100.0g (material weight is made up of Na + , 4.5%; Al 3+ , 9.5%; SO 4 2- , 60.5%; F - , 5.0%; H + , 1.0%; the remainder is other impurities), adding 38.9 g of preheated sodium hydroxide solution (18% by weight), fully reacting for 2 hours, and its pH value is 9.0. Dry to obtain sodium aluminum sulfate crude product 107g. After aging, crystallization and drying, 102.7g of sodium aluminum sulfate product was obtained.

Embodiment 3

[0023] Embodiment 3: direct double salt generation

[0024] In reactor, add by-product mixed sulfate material 100.0g (material weight is made up of Na + , 8.28%; Al 3+ , 10.3%; SO 4 2- , 76.6%; F - , 2.45%; H + , 2.21%); add 65.0 g of preheated sodium hydroxide solution (weight concentration is 70%), add alumina powder 102.0 g, fully react for 4 hours, and its pH value is 0.0. Obtain 246.6g of crude product of sodium aluminum sulfate. After aging, crystallization and drying, 240.0 g of sodium aluminum sulfate product was obtained.

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PUM

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Abstract

The invention relates to a treatment method of a byproduct sulfate in the process of producing solar grade polysilicon through the silane method. The method comprises the following steps: adding acid substances (such as sulfuric acid, hydrochloric acid and the like) or alkaline substances (such as sodium hydroxide, sodium carbonate, sodium bicarbonate, calcium oxide, calcium hydroxide and the like) in the byproduct sulfate mixture according to the pH value of the mixture, to obtain mixed materials which mainly contain sodium aluminum sulfate, and drying the materials, to obtain a product with the purity of the sodium aluminum sulfate of more than 80%; and the method can also carry out low-temperature crystallization or alkaline chemical precipitation on water solution of the byproduct sulfate mixture, thereby respectively obtaining anhydrous sodium sulfate, sodium sulfate decahydrate, anhydrous aluminum sulphate (glauber salt), crystalline aluminum sulfate, polymer aluminum sulfate, aluminum hydroxide and other products, and solving the problem of utilizing solid wastes produced in the polysilicon production process.

Description

technical field [0001] The present invention relates to the processing method of by-product sulfate in the process of producing solar-grade polysilicon by silane method, wherein in the by-product sulfate mixture, according to the pH value of the mixture, acidic (such as sulfuric acid, hydrochloric acid, etc.) or alkaline (such as sodium hydroxide, Sodium carbonate, sodium bicarbonate, calcium oxide, calcium hydroxide, etc.) substances, obtain the mixed material based on sodium aluminum sulfate with a pH value in the range of 0-9, and dry the material to obtain sodium aluminum sulfate with a purity greater than 80%. The product. The by-product sulfate mixture can also be processed to obtain anhydrous sodium sulfate, sodium sulfate decahydrate, anhydrous aluminum sulfate (yuanming powder), crystalline aluminum sulfate, polyaluminum sulfate, aluminum hydroxide and other products. Background technique [0002] The new silane thermal decomposition method is divided into two type...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00C01B17/96C01D7/26
CPCY02W30/20
Inventor 杨更亮李志远
Owner 杨更亮
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