Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for removing impurity B in metallurgical silicon through wet process

A technology for metallurgical grade silicon and wet removal, applied in the field of metallurgy, can solve the problems of high cost, difficult operation, strong corrosion of equipment, etc., and achieve the effects of low cost, easy operation and improved product recovery rate.

Active Publication Date: 2013-03-27
KUNMING UNIV OF SCI & TECH
View PDF6 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, the existing wet B removal technology uses high-concentration acid, which is highly corrosive to equipment, difficult to operate, and high in cost

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for removing impurity B in metallurgical silicon through wet process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) Crushing and finely grinding metallurgical grade silicon into -100 mesh silicon powder, in which the B content is 25ppmw;

[0024] (2) Add the silicon powder in step (1) to the mixed aqueous solution composed of ammonium chloride, sodium fluoride and methanol according to the liquid-solid ratio of 2:1, wherein the mass fraction of ammonium chloride in the mixed aqueous solution is 5% , the mass fraction of sodium fluoride is 2%, the volume fraction of methanol is 5%, and then heated to 40°C for stirring and leaching for 0.5h;

[0025] (3) After the liquid-solid separation of the mixture in step (2) is carried out with a conventional filter press, the filter cake is washed twice with pure water to neutrality and then dried to obtain metallurgical-grade silicon without impurity B. The content of impurity B in the obtained high-purity silicon is 9.8 ppmw.

Embodiment 2

[0027] (1) Crushing and finely grinding metallurgical grade silicon into -300~-400 mesh silicon powder, of which the B content is 34ppmw;

[0028] (2) Add the silicon powder in step (1) to the mixed aqueous solution composed of ammonium chloride, sodium fluoride and methanol according to the liquid-solid ratio of 5:1, wherein the mass fraction of ammonium chloride in the mixed aqueous solution is 15% , the mass fraction of sodium fluoride is 10%, the volume fraction of methanol is 10%, and then heated to 70°C for stirring and leaching for 4h;

[0029] (3) After the mixture in step (2) is subjected to liquid-solid separation by conventional vacuum filtration, the filter cake is washed several times with distilled water until it becomes neutral, and then dried to obtain metallurgical-grade silicon without impurity B. The impurity B in the obtained high-purity silicon is 15 ppmw.

Embodiment 3

[0031] (1) Crushing and finely grinding metallurgical grade silicon into -600 mesh silicon powder;

[0032] (2) Add the silicon powder in step (1) to the mixed aqueous solution composed of ammonium chloride, sodium fluoride and methanol according to the liquid-solid ratio of 10:1, wherein the mass fraction of ammonium chloride in the mixed aqueous solution is 30% , the mass fraction of sodium fluoride is 20%, the volume fraction of methanol is 60%, and then heated to 100°C for stirring and leaching for 7h;

[0033] (3) After the mixture in step (2) is subjected to liquid-solid separation by conventional vacuum filtration, the filter cake is washed several times with deionized water until it becomes neutral, and then dried to obtain metallurgical-grade silicon without impurity B. The impurity B in the obtained high-purity silicon was 7.3 ppmw.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a method for removing an impurity B in metallurgical silicon through a wet process. The metallurgical silicon is ground into silicon powder of minus 100-minus 600 meshes; the silicon powder is added into a mixed aqueous solution which consists of ammonium chloride, sodium fluoride and methanol according to a liquid-solid ratio of (2:1)-(10:1), and the mixture is heated to 40-100 DEG C for agitation leach for 0.5-7 hours; and then, after the liquid-solid separation, a filter cake is washed with water for a plurality of times to be neutral and then is dried, so that the metallurgical silicon is removed with the impurity B is obtained. The method for moving the impurity B is simple in equipment, is easy to operate, consumes less energy and is low in cost; and the method does not need neither high pressure condition nor high temperature, is carried out at normal pressure and low temperature and does not need special equipment, and a conventional agitation reactor can satisfy technological requirements. The method is a simple and effective method for removing B in the metallurgical silicon, leachate can be recycled, and the method is simple to operate and is low in cost.

Description

technical field [0001] The invention relates to a method for removing B in metallurgical-grade silicon by hydrometallurgy in the preparation of solar-grade silicon by metallurgical methods, and belongs to the technical field of metallurgy. Background technique [0002] With the depletion of fossil energy and the increasing impact on the environment, finding new environmentally friendly alternative energy has become an urgent task in today's era. High expectations have become the focus of research in countries all over the world. Although there are many ways to use solar energy, photovoltaic power generation is undoubtedly the most influential way. High-purity silicon is the basic material for photovoltaic power generation, and most photovoltaic cells use high-purity polycrystalline silicon or monocrystalline silicon. [0003] The purity of high-purity silicon that can be used for photovoltaic power generation is required to be greater than 6N, and the content of impurity B...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 谢克强马文会麦毅魏奎先周阳伍继君吕国强朱文杰刘大春杨斌戴永年
Owner KUNMING UNIV OF SCI & TECH