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Method for preparing high purity silicon with silicon waste material purification

A silicon waste, high-purity technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problem of waste of silicon raw materials and achieve high production efficiency

Inactive Publication Date: 2008-10-29
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, after several times of redrawing, the crucible bottom material with rich impurities is wrapped or has a high content and is difficult to handle. At the same time, a large amount of monocrystalline silicon tailings are remelted and redrawn. The treated tailings are also discarded in large quantities, resulting in a great waste of silicon raw materials

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1: Using heavily doped crucible bottom material or single crystal silicon tailings as raw materials, the silicon content is 91wt%, and the main impurity components are Sb content of 74120ppmw, Fe content of 5000ppmw, Ca content of 2600ppmw, and Al content of 5000ppmw.

[0016] Put the raw material in a vacuum directional condensation refining furnace, first heat the raw material to a temperature of 1450°C, and a vacuum degree of 1.0×10 -4 Pa, keep warm for 0.5h, conduct vacuum evaporation, and then stretch at a speed of 800μm / s, the cooling method is air cooling, and carry out vacuum directional condensation refining and purification treatment.

[0017] Implementation results: After the heavily doped crucible bottom material or single crystal silicon tailings are processed, take a sample of the middle part of the ingot after vacuum directional condensation and refining, and test it. The purity is 99.999%, and the content of Fe is 2ppmw, and the content of Al is ...

Embodiment 2

[0018] Example 2: use crucible bottom material or single crystal silicon tailings as raw materials, the silicon content is 99wt%, the main impurity component Fe content is 3500ppmw, the Ca content is 1000ppmw, and the Al content is 4500ppmw.

[0019] After preliminary crushing and pretreatment, the raw materials are placed in a vacuum condensation refining furnace. First, the sample is heated to a temperature of 1550°C and a vacuum degree of 1.0×10 -2 Pa, heat preservation for 13h, vacuum evaporation, and then stretching at a speed of 20μm / s, the cooling method is water cooling, and vacuum directional condensation refining purification treatment.

[0020] Implementation results: After the crucible bottom material or monocrystalline silicon tailings are processed, take a sample of the middle part of the ingot after vacuum directional condensation and refining, and test the purity of 99.9995%, in which the content of iron impurities is 0.8ppmw, and the content of aluminum impurit...

Embodiment 3

[0021] Example 3: using crucible bottom material or monocrystalline silicon tailings as raw materials, the silicon content is 99.9wt%, and the main impurity components Fe content is 650ppmw, Ca content is 100ppmw, and Al content is 150ppmw.

[0022] After preliminary crushing and pretreatment, the raw materials are placed in a vacuum directional condensation refining furnace. First, the sample is heated to a temperature of 1650°C and a vacuum degree of 1.0×10 -3 Pa, heat preservation for 20h, vacuum evaporation, and then stretching at a speed of 3μm / s, the cooling method is metal alloy liquid cooling, and vacuum directional condensation smelting purification treatment.

[0023] Implementation results: After the crucible bottom material or monocrystalline silicon tailings are processed, take a sample of the middle part of the ingot after vacuum directional condensation and refining, and test it. The purity is 99.9999%, and the content of iron impurities is 0.3ppmw, and the conte...

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PUM

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Abstract

The invention relates to a method for purifying the silicon waste to prepare high purity silicon. The tailing material of massive monocrystal line silicon with the silicon content of more than 90 percent or pot material as raw material is treated by vacuum evaporation and directional condensation, refinement and purification. First, the raw material is heated to the temperature above the melting point of the raw material and carries out vacuum evaporation in the vacuum state with heat preservation to remove the volatile impurity, then, the raw material is stretched and cooled to carry out vacuum directional condensation, refinement and purification. Therefore, the metal impurities are collected at one end, which not only removes the non-metallic impurities but also removes the metallic impurities. The high purity silicon with purity of more than 99.999 percent can be prepared.

Description

1. Technical field [0001] The invention relates to a method for preparing high-purity silicon by purifying silicon waste, and belongs to the technical field of silicon waste recovery and treatment by vacuum metallurgy, in particular to a method for preparing high-purity silicon by purifying silicon waste. 2. Background technology [0002] At present, my country's renewable energy scale is only 8%, and the future development space is very broad. As the energy source with the most potential in the 21st century, the solar energy industry has made considerable progress in research and development, industrialization, and market development. The solar cell industry has also become one of the fastest and steadily developing sunrise industries in the world. Polysilicon is a basic material for the electronics industry and the solar photovoltaic industry. In recent years, driven by the development of the solar cell industry, the polysilicon market has grown rapidly. The shortage of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 马文会戴永年杨斌刘大春梅向阳魏奎先唐绍雨郭宽新于站良徐宝强伍继君汪镜福郁青春姚耀春
Owner KUNMING UNIV OF SCI & TECH
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