Preparation of hyperpure metallurgy silicon

The technology of metallurgical silicon and purification method is applied in the preparation of ultra-pure metallurgical silicon by adding a slag-forming agent to purify industrial silicon in a vacuum melting furnace, and in the field of primary purification of silicon for solar cells. Reports, unstable quality and other problems, to achieve the effects of production safety, prevention of silicon oxidation, and fast heat transfer

Inactive Publication Date: 2009-01-28
贵阳高新阳光科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this process is relatively simple, gas ventilation is very dangerous, which limits the imple...

Method used

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Examples

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Effect test

Embodiment 1

[0010] A preparation method of ultra-pure metallurgical silicon, the steps are:

[0011] 10Kg of 99.5% metallurgical silicon was pulverized and ball milled to a particle size of 100 mesh. Put the silicon powder into 10Kg of hydrochloric acid solution with a mass concentration of 10% and soak for 24 hours, then centrifugally filter and separate, wash with pure water until the pH is neutral; dry the silicon powder after wet purification in a vacuum drying oven; Take 5000g dried silicon powder and 600g Na 2 O-CaO-SiO 2 The slagging agent is mixed and put into a 3000ml quartz crucible, and the quartz crucible is placed in a furnace with a jacketed graphite heating element. Start the power supply for induction heating, and at the same time blow protective gas argon into the furnace to prevent silicon oxidation; maintain a vacuum of 6000Pa, when the temperature in the furnace reaches 1400°C, keep the silicon in a molten state for 40 minutes; (6) Pour out the molten silicon slag, ...

Embodiment 2

[0013] A preparation method of ultra-pure metallurgical silicon, the steps are:

[0014] 100 kg of 99.5% metallurgical silicon was pulverized and ball milled to a particle size of 150 mesh. Put the silicon powder into 300kg of hydrochloric acid solution with a mass concentration of 12% and soak for 30 hours, then centrifugally filter and separate, wash with pure water until the pH is neutral; dry the silicon powder after wet purification in a vacuum drying oven; Take 50kg of dried silicon powder and 7.5kg of slagging agent Na2O-CaO-SiO2 and mix them into an 80-liter quartz crucible. The quartz crucible is placed in a furnace with a jacketed graphite heating element. Start the power supply for induction heating, and at the same time blow protective gas argon into the furnace to prevent silicon oxidation; maintain a vacuum of 8000Pa, when the temperature in the furnace reaches 1450 °C, keep the silicon in a molten state for 50 minutes; (6) Pour out the molten silicon slag, leav...

Embodiment 3

[0016] A preparation method of ultra-pure metallurgical silicon, the steps are:

[0017] 100 kg of 99.8% metallurgical silicon was pulverized and ball milled to a particle size of 100 mesh. Put the silicon powder into 300kg of hydrochloric acid solution with a mass concentration of 15% and soak for 30 hours, then centrifugally filter and separate, wash with pure water until the pH is neutral; dry the silicon powder after wet purification in a vacuum drying oven; Take 50kg of dried silicon powder and 5kg of slagging agent BaO-CaO-SiO 2 Mix evenly and put into 80 liters of quartz crucibles, and the quartz crucibles are placed in the melting furnace of the jacketed graphite heating element. Start the power supply for induction heating, and at the same time blow protective gas argon into the furnace to prevent silicon oxidation; maintain a vacuum of 6000Pa, when the temperature in the furnace reaches 1450°C, keep the silicon in a molten state for 50 minutes; (6) Pour out the mol...

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Abstract

A preparation method of ultrapure metallurgical silicon belongs to the purification technology of silicon, and the invention provides a primary purification method of a silicon material which totally contains less than 100ppma of impurities and is used for preparing solar cells. In the method, the physical metallurgical technology is used, industrial silicon powder (purity is higher than 99.5%) is taken as a raw material,, after being chemically pre-processed by acid, the silicon powder is evenly mixed with a slagging agent and put in a quartz crucible of a smelting furnace, protective gas is blown to the smelting furnace at micro-vacuum state or normal pressure; induction heating is carried out till the temperature of the smelting furnace is 1400-1700 DEG C, and the silicon metal is melted into a silicon melt; slagging is carried out to remove impurities; and finally directional solidification is carried out to obtain the ultrapure metallurgical silicon totally containing less than 100ppma of impurities. The method can remove most of metal impurity elements from silicon, especially can reduce the contents of B and P in the silicon effectively, and meet the demand of low-cost solar cells for silicon materials. The method saves equipment investment, reduces energy consumption, and has simple technology and easy operation in production.

Description

Technical field: [0001] The invention relates to a method for preparing ultra-pure metallurgical silicon, belongs to the technical field of silicon purification, and specifically relates to a method for preparing ultra-pure metallurgical silicon by using a vacuum smelting furnace to add a slagging agent to purify industrial silicon. In particular, it can be used in the primary purification method of silicon for solar cells. Background technique: [0002] Ultra-pure metallurgical silicon is generally used as silicon raw materials and silicon alloys for low-cost solar cell new processes. The purification of metallurgical silicon generally includes physical metallurgical methods and chemical methods. The ingredients are unchanged. The method of silicon purification using chemical principles is called chemical method. Its characteristic is that the composition of the silicon material changes during the purification process! The mature technology of chemical method is generall...

Claims

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Application Information

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IPC IPC(8): C01B33/037
CPCC30B29/06H01L31/1804C30B11/003C01B33/037Y02E10/547Y02P70/50
Inventor 吴展平
Owner 贵阳高新阳光科技有限公司
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