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Method for cleaning metallurgical silicon material

A metallurgical-grade silicon, cleaning technology, applied in cleaning methods and utensils, cleaning methods using liquids, chemical instruments and methods, etc., can solve problems such as high content, and achieve the effect of fast reaction rate

Inactive Publication Date: 2010-04-21
TRINA SOLAR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, the purity of metallurgical silicon in the industry can only reach the level of 5N, and the content of other metal impurities except phosphorus and boron is still relatively high, so there are still many problems in actual use.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] In the ventilated acid tank, configure the impurity removal solution according to the following volume ratio: HF:HNO 3 =1:20, HF concentration 48%, HNO 3 Concentration of 68%, soak and clean the metallurgical silicon material of grade 8N together for the same soaking time, take out the cleaned silicon material, and use pure water for secondary cleaning, constantly turn the raw material during washing, and then perform ultrasonic cleaning Wash with tertiary pure water, take out the silicon material when the pH of the washing solution is 7, and dry it. It is measured that the reaction rate ratio of metallurgical silicon material and IC material is 1.12:1, that is, the reaction rate of silicon material with high impurity content is higher than that of low impurity content under this ratio, and this acid ratio can selectively corrode silicon material Effect.

Embodiment 2

[0030] In the ventilated acid tank, configure the impurity removal solution according to the following volume ratio: HF:HNO 3 =1:20, HF concentration 48%, HNO 3 With a concentration of 68%, the metallurgical silicon material of grade 6N are soaked and cleaned together for the same soaking time, and the cleaned silicon material is taken out and cleaned with pure water for secondary cleaning. Washing and rinsing with tertiary pure water, until the pH of the washing solution is 7, pick up the silicon material and dry it. The measured reaction rate ratio of metallurgical silicon material to polycrystalline material is 1.05:1, that is, the reaction rate of silicon material with high impurity content is higher than that of low impurity content under this ratio, and this acid ratio is selective for silicon material The effect of corrosion.

Embodiment 3

[0032] In the ventilated acid tank, configure the impurity removal solution according to the following volume ratio: HF:HNO 3 =1:16, HF concentration 48%, HNO 3 The concentration is 68%. Soak and clean the metallurgical silicon material of grade 8N. Then perform ultrasonic cleaning and tertiary pure water cleaning, and when the pH of the washing solution is 7, pick up the silicon material and dry it. It is measured that the reaction rate ratio of metallurgical silicon material and IC material is 1.06:1, that is, the reaction rate of silicon material with high impurity content is higher than that of low impurity content under this ratio, and this acid ratio is selective for silicon material The effect of corrosion.

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PUM

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Abstract

The invention relates to a method for cleaning a metallurgical silicon material, which comprises the following steps: crushing a metal silicon material to below 3 centimeters; preparing acid-washing impurity removing solution, and preparing mixed acid by using hydrofluoric acid and nitric acid in a ratio of 1:12-20; soaking the crushed silicon material into the mixed acid, and stirring and cleaning the silicon material for certain time; fishing out the cleaned silicon material, cleaning the silicon material by secondary purified water, and continually turning over the silicon material; and ultrasonically cleaning the silicon material by third-grade purified water, fishing out the cleaned silicon material when the pH is equal to 7, and drying the silicon material. When the silicon material contains impurities, the electrochemical potential energy and the surface activity in an area are changed, the impurities are enriched, the reaction electromotive force of the impurities is large, the reaction rate with the acid is high, then the metal silicon material is subjected to impurity removal to a certain degree by using the principle, and the best selective corrosion effect is realized by allocating the acid matching ratio, concentration and reaction time so as to remove more impurities, realize the selective corrosion effect and meet the usage requirements of solar cells on the silicon material.

Description

technical field [0001] The invention belongs to the field of silicon material cleaning, in particular to a metallurgical-grade silicon material cleaning method capable of removing part of the enriched impurities during material washing before metallurgical-grade silicon material impurities are put into a furnace. Background technique [0002] Polysilicon is mainly produced by two methods: chemical purification and physical purification. Among them, the chemical purification methods mainly include the Siemens method (vapor phase precipitation reaction method), silane thermal decomposition method, and fluidized bed method; the physical purification methods mainly include the zone melting purification method (FZ ), Czochralski single crystal method (CZ), directional solidification polysilicon ingot method (casting method) and so on. Currently the most mature polysilicon purification process is the Siemens method, which can achieve a silicon purity of 99.9999999% (9N), but this ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B08B3/08B08B3/12B08B3/02
Inventor 陈雪黄振飞武雁榕
Owner TRINA SOLAR CO LTD
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