Method for slagging, boron removal and purification of metalluragical silicon

A purification method and metallurgical silicon technology, which is applied in the direction of chemical instruments and methods, silicon compounds, non-metallic elements, etc., can solve the problems of difficult to achieve boron removal effect, serious, complicated process, etc., to improve the overall boron removal effect, improve High energy utilization rate and boron removal efficiency

Active Publication Date: 2011-04-06
东海晶澳太阳能科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The above-mentioned process has the following problems in industrial application: (1), blowing or vacuuming have higher requirements on equipment; (2), do not add CaF 2 The boron removal effect of the slag system is still difficult to meet the requirements of solar-grade polysilicon, while CaF 2 (3) The compound slag-making method using two or more slag systems complicates the process, which is not conducive to industrial promotion

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] The method for purifying metallurgical silicon by making slagging and removing boron provided in this embodiment includes the following steps:

[0044] (1) Take 10kg of silicon material with a B content of about 7ppm as raw silicon;

[0045] (2) Mix SiO with a mass ratio of 44.5:55:0.5 2 、Na 2 CO 3 and Al 2 o 3 powder as a slagging agent;

[0046] (3) Put the raw silicon into the graphite crucible and heat it to 1500°C. After the silicon liquid is completely melted, add the slagging agent and stir evenly. After 30 minutes of heat preservation, remove the slag material after the upper layer reaction.

[0047] (4) Put the prefabricated slagging agent in the ratio of 1:20 to the silicon material, that is, take 0.5kg of slagging agent for each batch and put it into the silicon liquid, and carry out intermittent stirring. The stirring interval is 5 minutes, each time Stirring requires that the silicon liquid and the slagging agent be evenly mixed.

[0048] (5) After r...

Embodiment 2

[0050] Mix SiO at a mass ratio of 44:55:1 2 、Na 2 CO 3 and Al 2 o 3 Powder is used as a slagging agent; metallurgical silicon material is selected as raw material silicon, and the initial B content of raw material silicon is 7.84ppm; raw material silicon is put into a graphite crucible, and the intermediate frequency induction power is gradually increased to melt metallurgical silicon material into silicon liquid; when the silicon material is completely melted , reduce the power of the intermediate frequency furnace, and keep the temperature of the silicon liquid at 1450-1550 °C; the mass ratio of the slagging agent to the silicon material is 1:20 for each batch, and the stirring interval is 5 minutes. Each stirring requires the silicon liquid and the slagging agent Mix evenly, then remove the scum on the surface of the silicon liquid after the heat preservation reaction, use a graphite device to stir and scrape the scum when removing the scum, repeat the above steps (that ...

Embodiment 3

[0052] Mix SiO at a mass ratio of 38.5:60:1.5 2 、Na 2 CO 3 and Al 2 o 3 Powder is used as a slagging agent; metallurgical silicon material is selected as raw material silicon, and the initial B content of raw material silicon is 9.52ppm; raw material silicon is put into a graphite crucible, and the intermediate frequency induction power is gradually increased to melt metallurgical silicon material into silicon liquid; when the silicon material is completely melted , reduce the power of the intermediate frequency furnace, and keep the temperature of the silicon liquid at 1450-1550 °C; the mass ratio of the slagging agent to the silicon material is 1:10 for each batch, and the stirring interval is 5 minutes. Each stirring requires the silicon liquid and the slagging agent Mix evenly, then remove the scum on the surface of the silicon liquid after the heat preservation reaction, use a graphite device to stir and scrape the scum when removing the scum, repeat the above steps (t...

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Abstract

The invention discloses a method for slagging, boron removal and purification of metalluragical silicon, comprising the following steps of: selecting a metalluragical silicon material, heating until the metalluragical silicon is completely melted into a silicon solution and adjusting the temperature of the silicon solution; then adding a ternary slagging agent; removing scum on the surface of the silicon solution by stirring and carrying out a heat-insulating reaction; and standing the silicon solution for casting and then obtaining polysilicon, wherein the content of B in the polysilicon meets the solar level requirement. According to the method, complicated blowing equipment can be avoided, the process equipment can be simplified and the cost can be reduced; and the method is convenient for industrial application.

Description

Technical field [0001] The present invention is a photovoltaic technology field, which involves a method of purifying boron -deduction in metallurgical silicon slag. Background technique [0002] Boron (Boron, B) is a common impurities commonly used in solar polysilicon.The B content in the solar battery -grade polysilicon is generally below 0.3ppm. Excessive B content will cause negative effects such as decreased polycrystalline silicon resistivity and generate photosynthesis attenuation, which affects the conversion efficiency and stability of solar batteries.The boron content in industrial silicon is generally between 10 and 40 ppm and must be purified to use.At present, the preparation of high -purity polysilicon is mainly used in the Siemens method. This method belongs to the purity of chemical law. The process is complex, the early investment is large, the construction cycle is long, the energy consumption is large, and the pollution is serious.One of the research hotspots ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 黄新明尹长浩胡冰峰
Owner 东海晶澳太阳能科技有限公司
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