Method for recycling waste silicon solution

A technology of silicon liquid and silicon powder, applied in the direction of silicon, etc., can solve problems such as waste of social resources and environmental pollution

Inactive Publication Date: 2010-03-31
ZHEJIANG YUHUI SOLAR ENERGY SOURCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Therefore, treating waste silicon liquid as industrial waste is not only a great waste of social resources, but also causes certain pollution to the environment

Method used

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  • Method for recycling waste silicon solution

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Experimental program
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Effect test

Embodiment 1

[0022] A method for recovering and regenerating waste silicon liquid, characterized in that the method comprises the following steps:

[0023] a. The waste silicon liquid produced by cutting silicon rods is centrifuged, and the filter cloth has a pore size of 800 mesh to obtain silicon powder;

[0024] b. Place the separated silicon powder in a reaction kettle, add a strong oxidant to react, filter the reaction solution to remove organic carbon impurities, and the strong oxidant is a mixture of hydrogen peroxide and concentrated sulfuric acid with a ratio of 10:1;

[0025] c, place the silicon powder material obtained by secondary filtration in the reaction kettle, add dilute aqua regia to react, and the reaction solution is filtered and dried to remove metal and metal oxide impurities. The proportioning of hydrochloric acid, nitric acid and water in dilute aqua regia is 1:1:10;

[0026] d. Put the silicon powder obtained by filtering three times in a Czochralski single cryst...

Embodiment 2

[0028] Repeat the same steps as described in Example 1, but wherein the filter cloth aperture is 1500 mesh, the strong oxidant is a mixture of hydrogen peroxide and concentrated sulfuric acid with a ratio of 1:10, and the ratio of hydrochloric acid, nitric acid and water in dilute aqua regia is: 1:5:10, the temperature of the single crystal furnace is 1000°C.

Embodiment 3

[0030] Repeat the same steps as described in Example 1, but wherein the filter cloth aperture is 1000 mesh, the strong oxidant is a mixture of hydrogen peroxide and concentrated sulfuric acid with a ratio of 5:6, and the ratio of hydrochloric acid, nitric acid and water in dilute aqua regia is: 1:4:8, the temperature of the single crystal furnace is 900°C.

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Abstract

The invention relates to a method for recycling a waste silicon solution, in particular to a method for recycling a waste silicon solution generated in cutting silicon chip sheets. The method is characterized by comprising the following steps: carrying out centrifugal separation on the waste silicon solution generated in cutting silicon bars by filter cloth with the pore diameter of 800-1,500 meshes, and then obtaining silicon powder; putting the silicon powder obtained after separation in a reaction kettle; adding a strong oxidizer to react, and then filtering the reaction solution so as to remove organic carbon impurities, wherein the strong oxidizer is one of concentrated sulfuric acid, hydrogen peroxide and nitric acid or a mixed solution prepared from concentrated sulfuric acid, hydrogen peroxide and nitric acid; putting the silicon powder obtained after secondary filtration in the reaction kettle; adding diluted aqua fortis to react, and then filtering and drying the reaction solution so as to remove metal and metal oxide impurities; and putting the silicon powder obtained after third filtration in a Czochralski single crystal furnace; sufficiently reacting in the single crystal furnace in vacuum at the temperature of 800-1,000 DEG C so as to remove surface impurities, then cooling, and finally obtaining solar-grade silicon sheets. Applying the method can recycle most silicon powder in the waste silicon solution, and the silicon powder can be used for manufacturing solar batteries by downstream processing, thereby not only saving resources, but also not generating environmental pollution.

Description

Technical field: [0001] The invention relates to a method for recycling waste silicon liquid, in particular to a method for recycling and regenerating waste silicon liquid produced during silicon wafer cutting. Background technique: [0002] Solar energy is an important non-polluting, renewable, and inexhaustible new energy source for human beings. The solar cell industry has rapidly developed into a new sunrise industry that has attracted much attention in the world. Most current solar cells use crystalline silicon as the main material. Faced with the increasing demand for solar cells, on the other hand, there is a shortage of high-purity silicon raw materials used to manufacture solar cells. The limited raw material resources can no longer meet the needs of the solar industry, making the price of high-purity silicon materials for manufacturing crystalline silicon solar cells Soaring all the way, the manufacturing cost of solar cells continues to increase, restricting the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/02
Inventor 吴云才刘伟刘磊磊刘文涛
Owner ZHEJIANG YUHUI SOLAR ENERGY SOURCE
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