Method for comprehensively utilizing polysilicon by-product with low cost

A technology for by-products and polycrystalline silicon, which is applied in the field of low-cost comprehensive utilization of polycrystalline silicon by-products, can solve the problems of difficult recycling of hydrolyzed products, difficult to uniformly disperse the amount of alkali, and acidic or alkaline products, etc. The effect of low requirements and high utilization value

Inactive Publication Date: 2010-04-07
SICHUAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, due to the generated SiO 2 ·H 2 O and HCl are mixed together. In order to increase the conversion rate of the reaction, a large amount of cooling water is used to control the hydrolysis temperature at a certain value during the reaction, and the water consumption is large.
At present, the wastewater treatment of most manufacturers is not thorough enough, the added alkali is difficult to be evenly dispersed and the amount of alkali is difficult to be strictly controlled, resulting in uneven distribution of acid and alkali in the neutralized product and the treated product is acidic or alkaline, causing environmental pollution and difficult to achieve Clean manufacturing
[0012] In short, due to the difficulty in separating the precipitated silica and HCl from the hydrolysis product of the polysilicon by-product, the Cl in the precipitated silica - High content, high water consumption, difficult to recycle hydrolyzate

Method used

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  • Method for comprehensively utilizing polysilicon by-product with low cost
  • Method for comprehensively utilizing polysilicon by-product with low cost

Examples

Experimental program
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Effect test

Embodiment 1

[0050] In a closed reactor, polysilicon by-products and enhanced medium CO 2 Pressed in from the bottom of the reactor, water reacts with by-products in a spraying manner from the top of the reactor, the molar ratio of polysilicon by-products to river water is n 多晶硅副产物 : n 水 =1:3.5.

[0051] The upper part of the reaction kettle uses an acid-resistant vacuum pump to reduce the pressure in the reaction kettle by 0.1 atmosphere, so that the pressure in the kettle reaches 0.9 atmosphere, and the extracted gas is absorbed by water to form hydrochloric acid or react with limestone to form calcium chloride, and the rest of the gas is separated and emptied .

[0052] Add flocculant (polyacrylamide) to the silica colloid in the tank under stirring to form a precipitate, filter after sedimentation, mix the mother liquor with the supernatant and use it as a raw material for polysilicon by-product hydrolysis reaction, and filter cake silica Roasting at 500°C removes the flocculant, an...

Embodiment 2

[0055] In a closed reactor, polysilicon by-products and enhanced medium CO 2 Pressed in from the bottom of the reactor, water reacts with by-products in a spraying manner from the top of the reactor, the molar ratio of polysilicon by-products to river water is n 多晶硅副产物 : n 水 =1:5.

[0056] The upper part of the reaction kettle uses an acid-resistant vacuum pump to reduce the pressure in the reaction kettle by 0.5 atmospheres, so that the pressure in the kettle reaches 0.5 atmospheres, and the extracted gas is absorbed by water or reacted with other reaction media and then separated and emptied.

[0057] Add flocculant (polyacrylic acid) to precipitate the silica colloid in the tank under the stirring action. After filtering, mix the mother liquor with the supernatant and use it as the raw material for polysilicon by-product reaction. The filter cake silica is roasted at 700°C The flocculant is removed, while the generated CO 2 Returning to the reactor for recycling, it play...

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Abstract

The invention relates to a method for comprehensively utilizing a polysilicon by-product with low cost, which belongs to the technical field of polysilicon production. The technical problem to be solved by the invention is to effectively separate a hydrolysate of the polysilicon by-product to obtain precipitated silica and HCl and comprehensively utilize the polysilicon by-product with low cost. The technical scheme of the invention comprises the steps of: performing a hydrolysis reaction on the polysilicon by-product and water in a mol ratio of 1: 3-6; separating gas HCl and a small quantity of H2 from the hydrolysate in a decompression separation mode; and adding a flocculating agent into a liquid from which the gas is separated to form a precipitate, and roasting the precipitate obtained after solid-liquid separation to remove the flocculating agent to obtain the precipitated silica. The method has low reaction temperature, does not need heating and cooling, has high hydrolysis conversion rate and good separation effect, can make full use of Si and Cl in the by-product, has low requirement on equipment, has high utilization value of the hydrolysate, and can realize consumption reduction, energy conservation and comprehensive utilization of resources.

Description

technical field [0001] The invention relates to a method for comprehensively utilizing polysilicon by-products at low cost, and belongs to the technical field of polysilicon production. Background technique [0002] Solar photovoltaic power generation is a green renewable energy technology that has been researched more at present, and has obvious advantages, which has attracted great attention from all countries in the world. In 2006, my country's production capacity in the field of photovoltaics reached more than 10% of the world's share, second only to Japan and Europe, ranking third in the world. It is estimated that by 2010, the output of photovoltaic power generation products will exceed 1000MW, becoming the world's largest producer of solar cells. As the cornerstone of the development of solar energy and microelectronics industry, polysilicon is the key raw material for integrated circuits and photovoltaic power generation. In recent years, the output is far from meeti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/12C01B7/03
Inventor 王贵欣闫康平严立
Owner SICHUAN UNIV
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