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Method for efficiently removing boron and phosphorus in silicon

A high-efficiency and high-purity technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of high cost, low boron and phosphorus removal efficiency, and achieve low cost, high industrial value, and low melting temperature. Effect

Pending Publication Date: 2019-09-13
XINYANG NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems of high cost and low removal efficiency of boron and phosphorus when preparing solar grade silicon from metallurgical grade silicon in the prior art, the present invention provides a method for efficiently removing boron and phosphorus in silicon

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Mix 60g of metallurgical-grade silicon, 140g of high-purity aluminum, and 1.4g of high-purity hafnium, put them into an alumina crucible, and heat up to 1200°C at a rate of 3K / min in a well-type furnace; stir with a quartz rod to mix evenly, and then Cool down to 25°C at a rate of 1K / min to obtain solidified Alloy I; put Alloy I in hydrochloric acid at 50°C, and place it for 48 hours to remove the matrix of Alloy I to obtain primary silicon wafer I; use a mortar to grind the primary silicon wafer I Obtain silicon particles with a particle size of <10 μm; put the silicon particles in hydrochloric acid at 50° C. for 48 hours, then wash the silicon particles with deionized water and dry them at 50° C. Mix 30g of dried silicon particles, 70g of high-purity aluminum, and 0.15g of high-purity calcium, put them into an alumina crucible, heat up to 1300°C at a rate of 3K / min in a pit furnace; stir with a quartz rod to mix them Uniform, and then cool down to 25°C at a rate of 1K...

Embodiment 2

[0027] Mix 60g of metallurgical-grade silicon, 140g of high-purity aluminum, and 7g of high-purity hafnium, put them into an alumina crucible, and raise the temperature to 1200°C at a rate of 3K / min in a well-type furnace; stir with a quartz rod to mix evenly, and then Cool down at a rate of 1K / min to 28°C to obtain solidified Alloy I; put Alloy I in hydrochloric acid at 50°C, and place it for 48 hours to remove the matrix of Alloy I to obtain primary silicon wafer I; use a mortar to grind primary silicon wafer I Obtain silicon particles of <10 μm; place the silicon particles in hydrochloric acid at 50° C. for 48 hours, then wash the silicon particles with deionized water and dry them at 60° C. Mix 30g of dried silicon particles, 70g of high-purity aluminum, and 0.7g of high-purity calcium, put them into an alumina crucible, and heat up to 1300°C at a rate of 3K / min in a pit furnace; stir them with a quartz rod to mix them Uniform, then cool down to 28°C at a rate of 1K / min to...

Embodiment 3

[0029] Mix 60g of metallurgical-grade silicon, 140g of high-purity aluminum, and 13g of high-purity hafnium, put them into an alumina crucible, and raise the temperature to 1300°C at a rate of 3K / min in a well-type furnace; stir with a quartz rod to mix evenly, and then Cool down to 30°C at a rate of 1K / min to obtain solidified Alloy I; put Alloy I in hydrochloric acid at 50°C, and place it for 48 hours to remove the matrix of Alloy I to obtain primary silicon wafer I; use a mortar to grind primary silicon wafer I Obtain silicon particles of <10 μm; place the silicon particles in hydrochloric acid at 50° C. for 48 hours, then wash the silicon particles with deionized water and dry them at 55° C. Mix 30g of dried silicon particles, 70g of high-purity aluminum, and 1.4g of high-purity calcium, put them into an alumina crucible, and heat up to 1200°C at a rate of 3K / min in a pit furnace; stir them with a quartz rod to mix them Uniform, then cool down to 30°C at a rate of 1K / min t...

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Abstract

The invention relates to the field of treatment of industrial silicon materials, specifically to a method for efficiently removing boron and phosphorus in silicon. The method comprises the following concrete steps: mixing and smelting metallurgical-grade silicon, high-purity aluminum and an element I to obtain a melt I; cooling the melt I to obtain a solidified alloy I; soaking the solidified alloy I in hydrochloric acid to obtain a primary silicon wafer I, crushing the primary silicon wafer I into particles, then immersing the particles in hydrochloric acid, cleaning the particles with waterand drying the particles to obtain silicon without impurity boron; mixing and smelting the silicon without the impurity boron, the high-purity aluminum and an element II to obtain a melt II; cooling the melt II to obtain a solidified alloy II; and soaking the solidified alloy II in hydrochloric acid to obtain a primary silicon wafer II, crushing the primary silicon wafer II into particles, then immersing the particles in hydrochloric acid, cleaning the particles with water and drying the particles to obtain silicon without impurity phosphorus. The method of the invention is simple in process,low in smelting temperature and low in energy consumption; after treatment, a phosphorus content is less than 0.23 ppmw, and a boron content is less than 0.45 ppmw; and the method has high industrialvalue.

Description

technical field [0001] The invention relates to the field of industrial silicon material processing, in particular to a method for efficiently removing boron and phosphorus in silicon. Background technique [0002] In recent years, my country's photovoltaic power generation industry has grown rapidly. It is necessary to import a large amount of raw material solar-grade silicon (polysilicon) from abroad every year. The purity of solar-grade silicon must reach 99.9999%. 0.7ppmw. The raw material is metallurgical grade silicon with a purity of about 98-99%. Metallurgical purification of silicon is a new type of silicon purification technology, which has the advantages of less investment, small footprint, fast plant construction, low energy consumption, little pollution, and low cost. The advantages. In the process of purifying silicon by metallurgical methods, silicon does not participate in chemical reactions, but uses the physical and chemical properties of impurities to ach...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
CPCC01B33/037
Inventor 李彦磊耿晓菊刘江峰涂友超
Owner XINYANG NORMAL UNIVERSITY
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