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Method for preparing solar grade silicon from silica serving as raw material

A solar-grade, silica technology, applied in chemical instruments and methods, silicon compounds, non-metallic elements, etc., can solve the problems of large environmental pollution and high production cost, and achieve the effects of low environmental pollution, low production cost and low power consumption

Inactive Publication Date: 2011-01-05
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the problems of high production cost and heavy environmental pollution, the present invention provides a method for preparing solar-grade silicon using silica as a raw material to meet the silicon raw material requirements required by the solar cell industry

Method used

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  • Method for preparing solar grade silicon from silica serving as raw material
  • Method for preparing solar grade silicon from silica serving as raw material

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Experimental program
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Effect test

Embodiment 1

[0022] A. Using silica as raw material and CaCl 2 It is a molten salt electrolyte, and the conventional reduction is carried out through the molten salt electrolyte at 900 ° C, so that the elemental silicon in the silica is directly electrolytically reduced to elemental silicon;

[0023] B. Add CuS to the elemental silicon in step A at a mass ratio of 1:3, and pass argon gas into it at 1000° C. for conventional crystallization treatment to obtain crystalline silicon;

[0024] C. according to the solid-liquid mass ratio of 1:5, the crystalline silicon of step B is placed in the hydrochloric acid solution that concentration is 5mol / L, pickling 20 hours;

[0025] D. Take out the acid-leached silicon, wash it with water 5 times, and dry it at 150°C for 2 hours;

[0026] E. Melting the dried silicon at 1500°C;

[0027] F. Put the molten silicon at a temperature of 1650°C and a pressure of 1×10 -2 Carry out vacuum evaporation under the vacuum condition of Pa;

[0028] G. After c...

Embodiment 2

[0030] A. Using silica as raw material and CaCl 2 It is a molten salt electrolyte, which is conventionally reduced by a molten salt electrolyte at 600°C, so that the elemental silicon in the silica is directly electrolytically reduced to elemental silicon;

[0031] B. Add CrCl to the elemental silicon obtained in step A at a mass ratio of 1:9 3 , and pass argon at 600°C for conventional crystallization treatment to obtain crystalline silicon;

[0032] C. according to the solid-liquid mass ratio of 1:1, the crystalline silicon of step B is placed in the hydrochloric acid solution that concentration is 3mol / L, acid leaching for 48 hours;

[0033] D. Take out the acid-leached silicon, wash it with water 4 times, and dry it at 120°C for 3 hours;

[0034] E. Melting the dried silicon at 1650°C;

[0035] F. Vacuum evaporation of the melted silicon under vacuum conditions with a temperature of 1600° C. and a pressure of 10 Pa;

[0036] G. After condensing the molten silicon after...

Embodiment 3

[0038] A. Using silica as raw material and CaCl 2 It is a molten salt electrolyte, which is conventionally reduced by a molten salt electrolyte at 1000°C, so that the elemental silicon in the silica is directly electrolytically reduced to elemental silicon;

[0039] B. Add FeCl to the elemental silicon obtained in step A at a mass ratio of 1:6 3 and VF 3 , and pass argon gas at 1200°C for conventional crystallization treatment to obtain crystalline silicon;

[0040] C. According to the solid-liquid mass ratio of 1:8, the crystalline silicon of step B is placed in the hydrochloric acid solution that concentration is 1mol / L, pickling 2 hours;

[0041] D. Take out the acid-leached silicon, wash it twice with water, and dry it at 40°C for 2.5 hours;

[0042] E. Melting the dried silicon at 1450°C;

[0043] F. Carry out vacuum evaporation of the melted silicon under vacuum conditions with a temperature of 1620°C and a pressure of 5Pa;

[0044] G. Condensing the molten silicon ...

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Abstract

The invention provides a method for preparing solar grade silicon from silica serving as a raw material. In the method, the silica serves as the raw material, and CaCl2 is taken as a molten salt electrolyte; and the method comprises the following steps of: reducing the silica at the temperature of between 600 and 1,000 DEG C by using the molten salt electrolyte to directly electrolytically reduce silicon in the silica into elementary silicon; adding a compound into the elementary silicon according to a mass ratio of 1:3-9, and introducing protective gas at the temperature of between 600 and 1,200 DEG C for crystallization; putting the crystalized silicon into hydrochloric acid liquid with the concentration of between 1 and 5 mol / L according to a solid-liquid mass ratio of 1:1-8, and performing acid leaching for 2 to 48 hours; washing by using water for 2 to 5 times, and drying at the temperature of between 40 and 150 DEG C; melting the dried silicon at the temperature of between 1,450 and 1,650 DEG C, and performing vacuum evaporation under the vacuum condition at the temperature of between 1,600 and 1,650 DEG C and under the pressure of between 1*10<-2> and 1*10<10> Pa; and condensing the evaporated melt silicon at a condensation speed of between 0.1 and 5 mm / h to prepare the solar grade silicon. By reducing to remove impurities such as oxygen, phosphorus, aluminum, calcium, titanium and the like, and through high temperature crystallization and acid leaching for removing boron, the product has the purity of over 99.99991 percent, and the method has the advantages of short production flow, low cost and light environment pollution.

Description

technical field [0001] The invention relates to a method for preparing solar-grade silicon, in particular to a method for preparing solar-grade silicon by using silica as a raw material, and belongs to the technical field of metallurgical engineering. Background technique [0002] Solar power generation has the advantages of sufficient cleanliness, absolute safety, relative breadth and adequacy of resources, long life and maintenance-free, which are not available in other conventional energy sources. At present, silicon material is still the most important conversion material for solar cells, especially crystalline silicon solar cells. The high-cost production of polysilicon raw materials has seriously hindered the rapid development of the photovoltaic industry, and the direct use of the traditional Siemens method to produce solar-grade silicon, although the technology is mature, cannot meet the requirements due to its high production cost and heavy environmental load. The ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25B1/00C01B33/037
Inventor 马文会秦博魏奎先谢克强杨斌陈家辉周阳徐宝强刘大春伍继君曲涛刘永成陈建云戴永年
Owner KUNMING UNIV OF SCI & TECH
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