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Method for removing native polysilicon bar end-face graphite

A polycrystalline silicon rod, polycrystalline silicon technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., to achieve ideal oxidation effect and easy operation.

Inactive Publication Date: 2011-08-31
山西瑞邦启创孵化器管理有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004]Usually people use physical methods to remove the graphite chucks at both ends of the silicon rod. The raw materials without carbon are separated. For the raw materials with carbon, use the grinding wheel to grind off the graphite on the surface. This operation method needs to be ground one by one, which is quite troublesome and not conducive to batch processing. Silicon raw material, the loss is relatively large

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] First knock down the raw materials with graphite chucks at both ends of the polysilicon rod, break the raw materials into small pieces, and separate the raw materials with carbon from those without carbon; then put the raw materials with carbon into quartz boats and put them in the muffle furnace Increase the temperature to 900°C at a rate of 10°C / min per minute, and keep the temperature constant for two hours. During the calcination process, ventilation holes should be left in the furnace cavity, and then cooled naturally; then the cooled raw materials are taken out of the furnace, and the surface of the raw materials is scraped off with a stainless steel knife The ashes of ashes; Get the mixed acid leaching raw material of sufficient amount of nitric acid and hydrofluoric acid again 4 minutes, the weight percentage concentration of nitric acid is 90%, the weight percentage concentration of hydrofluoric acid is 47%, the mixture of nitric acid and hydrofluoric acid The r...

Embodiment 2

[0017] First knock down the raw materials with graphite chucks at both ends of the polysilicon rod, break the raw materials into small pieces, and separate the raw materials with carbon from those without carbon; then put the raw materials with carbon into quartz boats and put them in the muffle furnace Increase the temperature to 920°C at a rate of 15°C / min per minute, keep the temperature for two hours, leave vents in the furnace cavity during the calcination process, and then cool naturally; then take the cooled raw materials out of the furnace, and scrape off the surface of the raw materials with a stainless steel knife The ashes of ashes; Get the mixed acid leaching raw material of sufficient amount of nitric acid and hydrofluoric acid again 5 minutes, the weight percent concentration of nitric acid is 70%, the weight percent concentration of hydrofluoric acid is 55%, the mixture of nitric acid and hydrofluoric acid The ratio of parts by weight is 10:1. All the raw materia...

Embodiment 3

[0019] First knock down the raw materials with graphite chucks at both ends of the polysilicon rod, break the raw materials into small pieces, and separate the raw materials with carbon from those without carbon; then put the raw materials with carbon into quartz boats and put them in the muffle furnace Increase the temperature to 880°C at a rate of 8°C / min per minute, and keep the temperature constant for two hours. During the calcination process, vents should be left in the furnace cavity, and then cooled naturally; then the cooled raw materials are taken out of the furnace, and the surface of the raw materials is scraped off with a stainless steel knife The ashes of ashes; Get the mixed acid leaching raw material of sufficient amount of nitric acid and hydrofluoric acid again 3 minutes, the weight percentage concentration of nitric acid is 98%, the weight percentage concentration of hydrofluoric acid is 35%, the mixture of nitric acid and hydrofluoric acid The ratio of parts...

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PUM

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Abstract

The invention relates to a method for removing graphite on the end face of a protogenetic polysilicon rod, belongs to the technical field of processing of polysilicon rod materials, and provides a method for conveniently and fully removing the graphite on the end face of the silicon rod by a chemical method. The method adopts a proposal that: firstly, knocking away raw materials, which are provided with graphite chucks, on both ends of the polysilicon rod; secondly, crushing the raw materials into small blocks; thirdly, performing heat treatment on carbon-bearing raw materials on both ends ofprotogenetic polysilicon; fourthly, performing acid washing on the obtained product; fifthly, performing water washing on the obtained product until the obtained product is neutral; and sixthly, drying the obtained product. The heat treatment method comprises the following steps: packaging the carbon-bearing raw materials on both ends of the protogenetic polysilicon into a quartz boat, raising the temperature of a muffle furnace to between 880 and 920 DEG C at a temperature rise rate of between 8 and 15 DEG C per minute, maintaining at the temperature for 2 hours, and naturally cooling the obtained product. The method is widely applied to processing of the polysilicon rod materials in batches.

Description

technical field [0001] The invention discloses a method for removing graphite on the end face of a primary polycrystalline silicon rod, which belongs to the technical field of processing polycrystalline silicon rods. Background technique [0002] Due to environmental pollution and energy shortage, the rapid development of the solar photovoltaic industry has been promoted. Crystalline silicon solar cells are currently the most important solar cells. The raw materials used mainly include primary polysilicon, waste materials during chip processing, and scraps during silicon wafer processing. Among them, primary polysilicon is the main raw material. With the rapid development of the solar photovoltaic industry in recent years, the supply of polysilicon raw materials is very tight and the price is relatively high. The price of polysilicon raw materials per ton is more than 3 million. [0003] When polysilicon grows, graphite chucks are used to clamp both ends of the slender sili...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/021
Inventor 秦海滨任晓军许家云李金龙靳权
Owner 山西瑞邦启创孵化器管理有限公司