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Ingot-casting silicon powder with controllable grain size as well as preparation method and application thereof

A silicon powder and ingot casting technology, applied in the field of solar-grade polysilicon materials, can solve the problems of low degree of oxidation, low degree of surface oxidation of recycled silicon powder, easy melting of silicon powder, etc.

Active Publication Date: 2013-11-20
JIANGXI SAI WEI LDK SOLAR HI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the defects of the above-mentioned prior art, the present invention provides a method for preparing silicon powder for ingot casting with controllable particle size. This method can not only effectively remove metal impurities in silicon waste, but also improve the surface oxidation of recycled silicon powder. The shortcomings of low degree of oxidation and too fine particle size, and then solve the problem that silicon powder is easy to melt during ingot casting caused by low degree of oxidation on the surface of silicon powder or too fine particle size

Method used

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  • Ingot-casting silicon powder with controllable grain size as well as preparation method and application thereof
  • Ingot-casting silicon powder with controllable grain size as well as preparation method and application thereof
  • Ingot-casting silicon powder with controllable grain size as well as preparation method and application thereof

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Experimental program
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Effect test

Embodiment 1

[0039] combine as figure 1 As shown in the flow chart of the preparation process of silicon powder for ingot with controllable particle size, this embodiment provides a method for preparing silicon powder for ingot with controllable particle size, including the following steps:

[0040]S10. Disperse 20kg of silicon waste in 20L of water, then add 12L of hydrofluoric acid (49%) and 8L of hydrochloric acid (36.5%), stir and react for 30 minutes, then centrifuge to obtain 14kg of primary silicon powder;

[0041] S20. Disperse the primary silica powder obtained in S10 in 44L of water, add 10L of hydrochloric acid (36.5%) and 2L of nitric acid (68%), stir and disperse for 1 hour, then soak for 8 hours, and centrifuge to obtain 13.5kg of primary silicon powder. Silica fume;

[0042] S30, re-disperse the primary silica powder obtained by centrifugation of S20 in 20L of pure water, add 2L of hydrochloric acid (36.5%), stir and disperse for 1 hour, then centrifuge and wash the residua...

Embodiment 2

[0047] A method for preparing silicon powder for ingot casting with controllable particle size, comprising the steps of:

[0048] S10. Disperse 40kg of silicon waste in 36.5L of water, then add 1.2L of hydrofluoric acid (49.5%) and 2.3L of hydrochloric acid (38%), stir and react for 120 minutes, then centrifuge to obtain 30kg of primary silicon powder ;

[0049] S20. Disperse the primary silicon powder obtained in S10 in 37.6L of water, add 0.8L of hydrochloric acid (38%) and 1.6L of nitric acid (67%), stir and disperse for 2 hours, then soak for 10 hours, filter under reduced pressure, Obtain 29.5kg primary silicon powder;

[0050] S30. Re-disperse the primary silicon powder obtained by centrifugation of S20 in 29.2L of pure water, add 0.3L of nitric acid (67%), stir and disperse for 2 hours, then filter under reduced pressure and wash the residual acid solution with pure water 2 Secondary to pH neutral;

[0051] S40, repeat step S30 4 times, obtain 27.8kg primary silicon ...

Embodiment 3

[0054] A method for preparing silicon powder for ingot casting with controllable particle size, comprising the steps of:

[0055] S10. Disperse 3kg of silicon waste in 55L of water, then add 4.5L of hydrofluoric acid (49%) and 0.5L of hydrochloric acid (36%), stir and react for 10 minutes, then centrifuge to obtain 2.25kg of primary silicon powder ;

[0056] S20. Disperse the primary silicon powder obtained in S10 in 41L of water, add 3.3L of hydrochloric acid (36%) and 0.3L of nitric acid (65%), stir and disperse for 0.5 hours, then soak for 0.5 hours, and centrifuge to obtain 2.15 kg primary silicon powder;

[0057] S30. Redisperse the primary silicon powder obtained by centrifugation in S20 in 42.4L of pure water, add 0.6L of sulfuric acid (98%), stir and disperse for 0.5 hours, then centrifuge and wash the residual acid solution with pure water for 3 times to neutral pH;

[0058] S40, repeating step S30 5 times to obtain 2kg primary silicon powder;

[0059] S50, then p...

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Abstract

The invention provides a preparation method of ingot-casting silicon powder with controllable grain size. The preparation method comprises the following steps of: pickling silicon waste by using hydrofluoric acid and hydrochloric acid; pickling by using hydrochloric acid and nitric acid; pickling by using inorganic acid; carrying out solid-liquid separation and washing until the pH value is neutral, so as to obtain primary silicon powder; placing the primary silicon powder in a dryer with the temperature of 30-120 DEG C, setting the vacuum degree of the dryer as3.0*10<-2>-8.0*10<-2>MPa, and drying for 2-24 hours, so as to obtain the silicon powder with the grain size of 10 microns to 5 centimeters; grinding the obtained silicon powder, and screening by using a non-metal screen, so as to obtain the ingot-casting silicon powder with the grain size of 0.1-0.5mm. The preparation method can be used for solving a problem that the silicon powder is easy to melt during an ingot-casting process due to the low surface oxidization degree or extremely low grain size of the silicon powder. The invention further provides ingot-casting silicon powder with controllable grain size and application of the ingot-casting silicon powder in the field of solar poly-crystal silicon ingot preparation.

Description

technical field [0001] The invention relates to the field of solar-grade polysilicon materials, in particular to silicon powder for ingot casting with controllable particle size and its preparation method and application. Background technique [0002] With more and more attention paid to clean energy and the rapid development of solar cells, the production of polysilicon ingots, which are raw materials for solar cells, is also developing rapidly. The silicon wafers used for solar cells need to be cut and processed, and the silicon ingot needs to be cut with a diamond band saw blade to remove unqualified areas such as the head, tail and some shadows of the silicon ingot before slicing, so there is a problem during the sawing process. A large amount of silicon powder, the silicon content in these silicon powders is greater than 96%, and the particle size is mainly distributed between 8-12 μm. In addition, there are also some metal impurities, trace diamond particles, dust mud,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 付红平章金兵廖小根董一迪
Owner JIANGXI SAI WEI LDK SOLAR HI TECH CO LTD
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