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Purification method of polysilicon

A purification method and polysilicon technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of high energy consumption and cumbersome procedures, and achieve the effects of high removal rate, simple production process and low energy consumption

Active Publication Date: 2017-04-26
ANYANG INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Purification of boron in polysilicon by slagging method is cumbersome and requires high energy consumption, which requires technical improvement

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Grind the polysilicon to 36-260μm, calcinate to 1045℃ at a speed of 5℃ / min under the protection of argon, stay for 0.5h, draw air while heating, continue to heat at a speed of 1℃ / min to 1250℃, stay for 0.5 h. During the calcination process, methanol was dropped into the calcination furnace at 650° C. until the calcination was completed. The rate of methanol drop was 50 drops / min per 100 g of polysilicon. The polysilicon is then removed from the calciner and rapidly quenched in cold water. 10 parts of hydrofluoric acid by moles, 9 parts of nitric acid, and 72 parts of deionized water are used to prepare a pickling solution, and the quenched polysilicon and pickling solution with a quality of 4% of the pickling solution quality are poured into a polytetrafluoroethylene device, heated To 60°C, the magnetic stirring speed is 1450r / min, pickling for 2h, and then add 4 parts of β-D fructofuranose in moles to the pickling solution, and continue pickling for 3h. Filter the pi...

Embodiment 2

[0016] Grind the polysilicon to 38-280μm, calcinate to 1048°C at a speed of 5°C / min under the protection of argon, pump air while heating, stay for 0.5h, continue to heat at a speed of 1°C / min to 1252°C, stay for 0.5 h. During the calcination process, drop methanol into the calcination furnace at 656°C until the calcination is completed. The rate of dropping methanol is 50 drops / min per 100g of polysilicon, then take out the polysilicon from the calcination furnace and place it in cold water Quenching. 10 parts of hydrofluoric acid by moles, 10 parts of nitric acid, and 71 parts of deionized water are used to prepare a pickling solution, and the quenched polysilicon and pickling solution with a mass of 5% of the pickling solution quality are poured into a polytetrafluoroethylene device, heated Temperature 68°C, magnetic stirring speed 1420r / min, pickling for 2.5 hours, then add 4.6 moles of sorbitol to the pickling solution, continue pickling for 3.5 hours, filter the picklin...

Embodiment 3

[0018] Grind polysilicon to 46-280μm, calcinate to 1052°C at a speed of 5°C / min under the protection of argon, pump air while heating, stay for 0.5h, continue to heat at a speed of 1°C / min to 1250°C, stay for 0.5 h. During the calcination process, drop methanol into the calcination furnace at 659°C until the calcination is completed. The rate of dropping methanol is 50 drops / min per 100g of polysilicon. Finally, take out the polysilicon from the calcination furnace, and quickly Quenching. 10 parts of hydrofluoric acid by moles, 9 parts of nitric acid, and 72 parts of deionized water are used to prepare a pickling solution, and the quenched polysilicon and pickling solution with a quality of 6% of the pickling solution quality are poured into a polytetrafluoroethylene device, heated The temperature is 66°C, the magnetic stirring speed is 1450r / min, pickling for 2 hours, then add 5 moles of mannitol to the pickling solution, continue pickling for 4 hours, filter the pickling po...

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PUM

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Abstract

The invention discloses a purification method of polysilicon. The purification method of the polysilicon comprises the following steps: A: grinding the polysilicon, serving as a raw material, until the particle size is 36-260 mu m; B: calcining the polysilicon subjected to grinding from a room temperature to 1050 DEG C plus / minus 5 DEG C under argon shielding at a speed of 5 DEG C / min, then continuously heating the polysilicon at a speed of 1 DEG C / min to 1250 DEG C plus / minus 5 DEG C, and rapidly quenching silicon in cold water to the room temperature with cracks appearing on the surface of metal silicon; and C: pickling the polysilicon subjected to quenching in pickling liquor, then filtering the polysilicon, and washing the polysilicon with deionized water until neutral to obtain the polysilicon subjected to purification. With adoption of the purification method, the removing rate of polysilicon structure type impurities and adhesive impurities is high; and waste liquor produced after the polysilicon is pickled can be recycled as a chemical raw material without damaging environment.

Description

technical field [0001] The invention relates to a method for purifying silicon, in particular to a method for purifying polysilicon, and belongs to the field of chemical technology. Background technique [0002] Polycrystalline silicon is an important raw material for solar cell production, and its purity is required to be on the order of 5-6N. Purification of polysilicon by physical method requires less investment, quick results, and is environmentally friendly. It is a promising polysilicon purification technology. Physical purification of polysilicon includes pickling, alloying, vacuum smelting, directional solidification, slagging and electrolysis, among which pickling is favored for its low energy consumption, high purification efficiency, simple process and low production cost. Gradually popularize and use. Polysilicon impurities are divided into two types: adhesive impurities and structural impurities. Adhesive impurities are generally metal oxides or metal silicid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
CPCC01B33/037C01P2006/80
Inventor 刘振东李现常翟亚芳刘照亮
Owner ANYANG INST OF TECH