Boron removal method and system for industrial silicon refining

A technology of industrial silicon and silicon powder, applied in the field of metallurgy, can solve the problems of limited boron oxide solubility, low raw material, long refining and holding time, etc.

Active Publication Date: 2019-12-20
DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The following problems still exist in the current slagging method: (1) limited by the solubility of boron oxides in the slag agent, the existing B removal technology tends to increase the distribution coefficient value as much as possible to obtain low borosilicate, so it is necessary to Raw materials with as low a B content as possible
(2) The refining and holding time is too long, which increases the cost
(3) Slag and silicon are not easy to separate after refining

Method used

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  • Boron removal method and system for industrial silicon refining

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] In this embodiment, boron in industrial silicon powder is removed according to the following methods:

[0050] 1) Will be Ca(OH) by mass ratio 2 :Na 2 CO 3 :SiO2 2 =70:10:20 add the 2kg slagging agent that has been prepared into the graphite crucible of the intermediate frequency induction furnace, gradually increase the power of the intermediate frequency induction furnace to make the slagging agent rapidly heat up to fully melt, and obtain the slagging agent melt;

[0051] 2) Feed 1kg of industrial silicon powder with 100 mesh, B content of 10ppmw and argon gas mixture with a flow rate of 2L / min into the through hole on the bottom disc of the graphite hollow device (the height from the bottom of the graphite crucible is 10mm). Bottom of slag melt;

[0052] 3) After the industrial silicon powder is added and completely melted, the measured melt temperature is 1900°C, and the slagging agent melt is discharged through the discharge method at the bottom of the graphit...

Embodiment 2

[0083] 1) Will be Ca(OH) by mass ratio 2 :Na 2 CO 3 :SiO2 2 =70:10:20 add the 2kg slagging agent that has been prepared into the graphite crucible of the intermediate frequency induction furnace, gradually increase the power of the intermediate frequency induction furnace to make the slagging agent rapidly heat up to fully melt, and obtain the slagging agent melt;

[0084] 2) 2 kg of industrial silicon powder with 100 meshes and a B content of 10 ppmw and an argon gas mixture with a flow rate of 2 L / min are sent to the bottom of the slagging agent melt through the through hole on the bottom disk of the hollow device made of graphite;

[0085] 3) After the industrial silicon powder is added and completely melted, the measured melt temperature is 1800°C, and the slagging agent melt is discharged through the discharge method at the bottom of the graphite crucible;

[0086] 4) Pour the furnace body so that the silicon melt is poured from the sprue into a pure water tank with a ...

Embodiment 3

[0089] 1) Will be Ca(OH) by mass ratio 2 :Na 2 CO 3 :SiO2 2 =70:10:20 add the 2kg slagging agent that has been prepared into the graphite crucible of the intermediate frequency induction furnace, gradually increase the power of the intermediate frequency induction furnace to make the slagging agent rapidly heat up to fully melt, and obtain the slagging agent melt;

[0090] 2) 1 kg of industrial silicon powder with 100 meshes and a B content of 15 ppmw and an argon gas mixture with a flow rate of 2 L / min are sent to the bottom of the slagging agent melt through the through hole on the bottom disk of the hollow device made of graphite;

[0091] 3) After the industrial silicon powder is added and completely melted, the measured melt temperature is 1900°C, and the slagging agent melt is discharged through the discharge method at the bottom of the graphite crucible;

[0092] 4) Pour the furnace body so that the silicon melt is poured from the sprue into a pure water tank with a ...

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Abstract

The invention provides a boron removal method and system for industrial silicon refining. The method comprises the following steps of (1) performing heating on a slag forming agent which is placed into a graphite crucible to be molten to obtain a slag forming agent melt; (2) enabling silicon powder and argon to be added from the bottom in the graphite crucible, wherein the silicon powder is moltento form a silicon melt and rises from the bottom to the top of the slag forming agent melt; (3) after the reaction is complete, enabling the slag forming agent melt in the graphite crucible to be discharged from a discharge pipeline at the bottom of the graphite crucible; and (4) enabling the silicon melt to be discharged into water from a sprue in the upper part of the graphite crucible, and collecting silicon particles. Therefore, the boron removal method for industrial silicon refining is not limited by the influence of the size of the distribution coefficient of boron in the slag formingagent and a silicon liquid, the boron content in the product is low, the operation is simple and convenient, the time consumption is short, the cost is low, and the method is suitable for large-scaleapplication.

Description

technical field [0001] The invention relates to the field of metallurgy. Specifically, the present invention relates to a method and system for boron removal in industrial silicon refining. Background technique [0002] The performance indicators of metallurgical solar grade polysilicon in the new material product catalog are: low cost, low energy consumption, purity above 6N, boron (B) content <0.15ppm, phosphorus (P) <0.35ppm. As the raw material industrial silicon for preparing solar-grade polysilicon by metallurgical method, its purity is only 98%-99%, the B content is as high as 10-40ppmw, and the P content is 10-60ppmw. Therefore, the production steps of the existing metallurgical solar-grade polysilicon are: First remove B in industrial silicon by refining outside the furnace, then remove P, and finally remove metal impurities to obtain qualified solar-grade polysilicon. Existing refining boron removal technologies outside the furnace include hydrometallurgy, ...

Claims

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Application Information

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IPC IPC(8): C01B33/037
CPCC01B33/037
Inventor 吴志能王鹏周政李向东谌庆春廖添胡三元
Owner DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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