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

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

Active Publication Date: 2015-05-20
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 process flow chart of preparing silicon powder for ingot with controllable particle size, this embodiment provides a method for preparing silicon powder for ingot with controllable particle size, which includes 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%), fully stir the reaction for 30 minutes, and centrifuge to obtain 14kg of primary silicon powder;

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

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

Embodiment 2

[0047] A method for preparing silicon powder for ingot casting with controllable particle size includes the following steps:

[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%), fully stir the reaction for 120 minutes, and centrifuge to obtain 30kg of primary silicon powder ;

[0049] S20. Disperse the primary silicon powder obtained from 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, soak for another 10 hours, and filter under reduced pressure. Obtain 29.5 kg of primary silicon powder;

[0050] S30. Re-disperse the primary silicon powder obtained by S20 centrifugation 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 remaining acid with pure water 2 Secondary to neutral pH;

[0051] S40, repeat step S30 4 times to obtain 27.8kg of primar...

Embodiment 3

[0054] A method for preparing silicon powder for ingot casting with controllable particle size includes the following steps:

[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%), fully stir the reaction for 10 minutes, and centrifuge to obtain 2.25kg of primary silicon powder ;

[0056] S20. Disperse the primary silicon powder obtained from 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, soak for another 0.5 hours, and centrifuge to obtain 2.15 kg primary silicon powder;

[0057] S30. Re-disperse the primary silicon powder obtained by S20 centrifugation 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 remaining acid with pure water 3 times To neutral pH;

[0058] S40. Repeat step S30 5 times to obtain 2kg of primary silicon powder;

[0059] S50. Then put the 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 polycrystalline silicon materials, in particular to a silicon powder for ingot casting with controllable particle size, and a preparation method and application thereof. Background technique [0002] With more and more attention paid to clean energy, solar cells have developed rapidly, and the production of polycrystalline silicon ingots, the raw material for solar cells, has also developed rapidly. The silicon wafers used in solar cells need to be cut and processed, and the silicon ingots need to be cut with a diamond band saw blade to remove the unqualified areas such as the head, tail and some shadows of the silicon ingot before slicing. Therefore, it is produced 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 8-12μm. In addition, there are also some metal impurities, trace di...

Claims

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Application Information

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Patent Type & Authority Patents(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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