Method for preparing ultra-metallurgical grade silicon

A technology of metallurgical grade silicon and silicon source, applied in chemical instruments and methods, silicon compounds, non-metallic elements, etc., can solve the problems of high equipment investment and production cost, high energy consumption, inability to achieve large-scale production, etc. effect of difficulty

Inactive Publication Date: 2010-03-03
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to overcome the shortcomings of the prior art for producing ultra-metallurgical grade silicon, such as complex process, high energy consumption, high equipment investment and production cost, and inabilit

Method used

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preparation example Construction

[0011] The invention provides a method for preparing ultra-metallurgical grade silicon, which includes initial treatment of silicon source; acid leaching purification; pickling purification; ultrasonic heating purification; solid-liquid separation; screening and classification, wherein the acid leaching purification includes mechanical activation and Combined with pickling.

[0012] Wherein, the initial treatment of the silicon source includes crushing of the silicon source, washing to remove oil stains, and preliminary removal of impurities; the silicon source of the present invention can be a metal silicon block with abundant resources and low price, and the purity of the metal silicon block is preferably greater than 98%. The crushing is a crushing technique known to those skilled in the art, for example, after crushing the metal silicon block through a crusher for several times, the diameter of the crushed metal silicon is preferably 30-50 mesh. Washing and degreasing is a...

Embodiment 1

[0030] Commercially available metal silicon blocks were crushed to 40 meshes with a pulverizer, and impurities on the surface of the metal silicon were cleaned with detergent and ultrasonic equipment for 50 minutes, and iron impurities brought in during crushing were removed by electromagnetic separation. The silicon metal after magnetic separation was placed in a ball milling tank made of polytetrafluoroethylene, using zirconia balls as the ball milling medium, the ball-material ratio was 3:1, and 2mol / L hydrochloric acid solution was added, and the liquid-solid ratio was 12:1. Then fix the ball mill jar on a planetary ball mill and grind for 4 hours, and let it stand for 20 hours after grinding.

[0031] The metal silicon powder obtained after ball milling is separated from the acid-containing solution by means of centrifugal filtration, and washed several times with deionized water until the solution becomes neutral after washing. Then put metal silicon powder in the reacto...

Embodiment 2

[0032] Commercially available metal silicon blocks were crushed to 40 meshes with a pulverizer, and impurities on the surface of the metal silicon were cleaned with detergent and ultrasonic equipment for 50 minutes, and iron impurities brought in during crushing were removed by electromagnetic separation. The metal silicon after magnetic separation is placed in a ball milling tank made of polytetrafluoroethylene, with zirconia balls as the ball milling medium, the ball-material ratio is 3:1, and 2mol / L hydrochloric acid solution is added, and the liquid-solid ratio is 12:1. Then add 0.1% sodium lignosulfonate in a mass ratio to silicon powder, then fix the ball mill pot on a planetary ball mill to grind for 4 hours, and stand still for 20 hours after grinding.

[0033] The metal silicon powder obtained after ball milling is separated from the acid-containing solution by means of centrifugal filtration, and washed several times with deionized water until the solution becomes neu...

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Abstract

The invention provides a method for preparing ultra-metallurgical grade silicon, which comprises the following steps: initial treatment of a silicon source; acid leaching purification; acid cleaning purification; ultrasonic heating purification; solid-liquid separation; and sieve classification, wherein the acid leaching purification comprises the combined use of mechanical activation and acid cleaning. The method for preparing the ultra-metallurgical grade silicon has the advantages of simple process flow, less environmental pollution, low cost and easy large-scale production.

Description

【Technical field】 [0001] The invention relates to a preparation method of ultra-metallurgical grade silicon. 【Background technique】 [0002] Solar-grade silicon is the basic raw material for the photovoltaic industry, and its purity is generally 99.99-99.9999%. The raw material for preparing solar grade silicon is metal grade silicon, and the purity of metal grade silicon is generally 98-99.5%. The purification from metal-grade silicon to solar-grade silicon generally adopts the silane method (or Siemens method), which has the disadvantages of low yield, high energy consumption, serious pollution, high equipment investment and production costs. Due to the high equipment investment cost and manufacturing cost of solar-grade silicon in the prior art, the cost of solar cell components remains high, which seriously restricts the development of the photovoltaic industry. [0003] In the existing technology, ultra-metallurgical grade silicon with a purity greater than 99.99% is ...

Claims

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Application Information

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IPC IPC(8): C01B33/037
Inventor 陆先林王倩张才毓
Owner BYD CO LTD
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