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A method for removing impurity boron in industrial silicon by using aluminum and oxygen

An industrial silicon and oxygen technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of high cost, complex slag system, poor control of slag system ratio, etc., and achieve easy operation and simple equipment Effect

Active Publication Date: 2020-04-07
乌拉特后旗万鑫化工有限责任公司
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  • Application Information

AI Technical Summary

Problems solved by technology

This method is simple and easy to operate, and industrial application can also realize the recovery and utilization of metal zinc, but the ratio of zinc compounds has a great influence on the boron removal efficiency
Traditional slagging, refining, and boron removal have the disadvantages of complex slag system and poor control of slag system ratio
[0005] Aluminum-silicon alloy is a good refining flux for industrial silicon. Ullah et al. published a paper "Silicon crystal morphologies during solidification refining from Al-Si melts" (2011, 381(1): 212-218) in "Journal of Crystal Growth". Using aluminum-silicon melt to refine silicon in the directional solidification process has a good effect on the separation of impurities in silicon, but the aluminum content in aluminum-silicon melt reaches 62%-83%, the cost is high, and it is difficult to realize industrial application
The Institute of Plasma Physics of the Chinese Academy of Sciences published "A Method for Quickly Removing Phosphorus from Silicon by Airing Al-Si Alloy" (publication number CN104556043A). -1673K, to realize the rapid dephosphorization of the alloy melt, the gas introduced is H 2 or Ar-H 2 mixed gas or N 2 -H 2 mixed gas or H 2 O-H 2 Mixed gas, the removal rate of phosphorus can be increased from 46% to 93%, the patent does not involve the removal of boron

Method used

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  • A method for removing impurity boron in industrial silicon by using aluminum and oxygen

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Such as figure 1 Shown, this utilizes aluminum and oxygen to remove the method for impurity boron in industrial silicon, and its concrete steps comprise as follows:

[0028] (1) First, crush the industrial silicon block with a boron content of 24ppmw, and ball mill it until the particle size of the silicon powder is 200 mesh;

[0029] (2) Add metal aluminum particles (metal aluminum particle size 1-3mm, purity 99.99wt%) to the silicon powder in step (1) and mix evenly to obtain 100g of mixed material, the aluminum content in the mixed material is 5% by mass;

[0030] (3) Pass the mixed material obtained in step (2) through high-purity Ar at a flow rate of 500mL / min for 10 minutes, exhaust the air in the furnace, heat it to 1400°C at a heating rate of 20°C / min, and blow it in from the top at a flow rate of 200mL / min of high-purity Ar, silicon-aluminum melt alloying for 30min;

[0031] (4) After alloying the silicon-aluminum melt in step (3), keep the temperature const...

Embodiment 2

[0036] Such as figure 1 Shown, this utilizes aluminum and oxygen to remove the method for impurity boron in industrial silicon, and its concrete steps comprise as follows:

[0037] (1) First, crush the industrial silicon block with a boron content of 22ppmw, and ball mill until the particle size of the silicon powder is 150-200 mesh;

[0038] (2) Add metal aluminum particles (metal aluminum particle size 1-3mm, purity 99.99wt%) to the silicon powder in step (1) and mix evenly to obtain 100g of mixed material, the aluminum content in the mixed material is 10% by mass;

[0039] (3) Pass the mixed material obtained in step (2) through high-purity Ar at a flow rate of 500mL / min for 10 minutes, exhaust the air in the furnace, heat it to 1350°C at a heating rate of 20°C / min, and blow it in from the top at a flow rate of 200mL / min of high-purity Ar, silicon-aluminum melt alloying for 30min;

[0040](4) After alloying the silicon-aluminum melt in step (3), keep the temperature cons...

Embodiment 3

[0045] Such as figure 1 Shown, this utilizes aluminum and oxygen to remove the method for impurity boron in industrial silicon, and its concrete steps comprise as follows:

[0046] (1) First, crush the industrial silicon block with a boron content of 18.8ppmw, and ball mill it until the particle size of the silicon powder is 150-200 mesh;

[0047] (2) Add metal aluminum particles (metal aluminum particle size 1-3mm, purity 99.99wt%) to the silicon powder in step (1) and mix evenly to obtain 100g of mixed material, the aluminum content in the mixed material is 10% by mass;

[0048] (3) Pass the mixed material obtained in step (2) through high-purity Ar at a flow rate of 500mL / min for 10 minutes, exhaust the air in the furnace, heat it to 1350°C at a heating rate of 20°C / min, and blow it in from the top at a flow rate of 200mL / min of high-purity Ar, silicon-aluminum melt alloying for 30min;

[0049] (4) After alloying the silicon-aluminum melt in step (3), keep the temperatur...

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Abstract

The invention relates to a method for removing impurity boron from industrial silicon by using aluminum and oxygen, and belongs to the technical field of industrial silicon. The method comprises: breaking industrial silicon blocks, and carrying out ball milling until the particle size of silicon powder is 150-200 mesh; adding metal aluminum particles to the silicon powder, and uniformly mixing to obtain a mixed material; heating the obtained mixed material to a temperature of 1300-1400 DEG C, blowing high purity Ar at a flow rate of 500 mL / min from the top portion, and alloying the silicon aluminum melt for 20-30 min; after completing the alloying of the silicon aluminum melt, maintaining the temperature at the unchanged state, blowing the mixed gas of argon gas and oxygen gas from the top portion, and stopping the gas introduction after refining for 2-4 h so as to complete the gas blowing refining process; after completing the gas blowing refining process, stopping the heating, introducing Ar protection gas at a flow rate of 1000 mL / min from the bottom portion, taking out the crucible after the temperature in the furnace is reduced to a room temperature, and separating the residue layer on the sample surface to obtain a silicon block; and breaking the obtained silicon block, and washing the residual aluminum in the silicon by using hydrochloric acid so as to finally obtain the refined silicon powder. According to the present invention, aluminum is added to industrial silicon, and the boron impurity in the industrial silicon is efficiently removed through the oxygen blowing refining.

Description

technical field [0001] The invention relates to a method for removing impurity boron in industrial silicon by using aluminum and oxygen, and belongs to the technical field of industrial silicon. Background technique [0002] The chemical method represented by the improved Siemens method is still the largest polysilicon purification process in the world. Chemical methods can produce high-quality polysilicon products, which are generally used to produce electronic-grade silicon (EG-Si, >9N) with ultra-high purity requirements, while electronic-grade silicon and some scraps are usually used in solar cell silicon materials, but chemical methods The technological process is complicated, the environment is polluted, and the core technology is still monopolized by a few developed countries. Solar-grade silicon (SoG-Si, >6N) has slightly lower requirements for purity, generally around 6N, and the cost is also lower. With the advancement of technology and technology, metallur...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/039
CPCC01B33/039C01P2006/80
Inventor 伍继君杨鼎马文会魏奎先雷云谢克强秦博李绍元戴永年
Owner 乌拉特后旗万鑫化工有限责任公司
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