Method for removing impurity phosphorous in silicon

A technology of impurity and silicon melt, which is applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of adding danger, affecting the research progress of impurity phosphorus, and industrial application, so as to achieve low production cost, improve technical level and Effects on product quality and operational safety

Active Publication Date: 2013-09-25
四川纳毕硅基材料科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the method of wet leaching can partially remove the impurity phosphorus in silicon, there are some problems in the experimental research stage, and the ad

Method used

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  • Method for removing impurity phosphorous in silicon

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Experimental program
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Effect test

Embodiment 1

[0025] like figure 1 The process flow chart of the method for removing impurity phosphorus in silicon is as shown:

[0026] (1) Add 100kg at one time to 1000kg of industrial silicon melt (the content of impurity Fe is less than 0.2wt%, and the content of P is higher than 50ppmw) which is being refined outside the furnace and the temperature is higher than 1600°C. It meets the national standard YB / T5061-2007 Silicon-calcium alloy, obtain silicon melt with special composition, after 2 hours of refining outside the furnace, pour the silicon melt with special composition;

[0027] (2) Conduct controllable and segmented solidification of the silicon melt with special composition obtained in step (1): first condense the silicon melt with special composition at a condensation rate of 0.1°C / min, and then when the temperature drops to 1000°C, The condensation rate is condensed at 5°C / min, and finally when the temperature drops to 1000°C, the special composition silicon melt is natural...

Embodiment 2

[0031] like figure 1 The process flow chart of the method for removing impurity phosphorus in silicon is as shown:

[0032] (1) To the 1000kg industrial silicon melt (the content of impurity Fe is less than 0.2wt%, and the content of P is higher than 50ppmw) which is being refined outside the furnace and the temperature is higher than 1600℃, add 150kg in two times, which meets the national standard YB / T5061- The 2007 silicon-calcium alloy obtained a silicon melt with a special composition. After 4 hours of refining outside the furnace, the silicon melt with a special composition was poured;

[0033] (2) Controlled and segmented solidification of the silicon melt with special composition obtained in step (1): first condense the silicon melt with special composition at a condensation rate of 3°C / min, and then when the temperature drops to 1400°C, The condensation rate is condensed at 15°C / min, and finally when the temperature drops to 900°C, the special composition silicon melt...

Embodiment 3

[0037] like figure 1 The process flow chart of the method for removing impurity phosphorus in silicon is as shown:

[0038] (1) Add 180kg at one time to 1000kg of industrial silicon melt (the content of impurity Fe is less than 0.2wt%, and the content of P is higher than 50ppmw) which is being refined outside the furnace and the temperature is higher than 1600°C. It meets the national standard YB / T5061-2007 Silicon-calcium alloy, obtain silicon melt with special composition, after 3 hours of refining outside the furnace, pour the silicon melt with special composition;

[0039] (2) Controlled and segmented solidification of the silicon melt with special composition obtained in step (1): first condense the silicon melt with special composition at a condensation rate of 5°C / min, and then when the temperature drops to 1200°C , the condensation rate is condensed at 20°C / min, and finally when the temperature drops to 800°C, the special-component silicon melt is naturally cooled to ...

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Abstract

The invention relates to a method for removing impurity phosphorous in silicon, belonging to the technical field of silicon product deep processing. The method comprises the following steps of: adding a silicon calcium alloy into industrial silicon melt which is subjected to external refining to obtain special component silicon melt and pouring the special component silicon melt after the external refining is finished; condensing the poured special component silicon melt to room temperature through controllable grade condensation to finally obtain a special component silicon product; treating the special component silicon product through finishing, crushing, ball milling, sieving and magnetic separation processes to obtain special component silicon product powder; adding the special component silicon product powder into an acidic solution for acid leaching to finally obtain a low-phosphorus silicon product. The method has the advantages of safety in operation, easiness in control, high impurity phosphorus removal efficiency, capability of being combined with the conventional industrial silicon production process, low production cost, easiness in implementation of batch production and the like.

Description

technical field [0001] The invention relates to a method for removing impurity phosphorus in silicon, and belongs to the technical field of deep processing of silicon products. Background technique [0002] Phosphorus is an important impurity element in silicon, which has a significant impact on the conversion efficiency of solar cells. In the new process of preparing solar-grade polysilicon by metallurgical methods, in order to remove impurity phosphorus, people have adopted various methods or means. Due to the high vapor pressure of phosphorus, the use of vacuum volatilization to remove phosphorus has become one of the research hotspots, and good progress has been made. Ma Wenhui of Kunming University of Science and Technology and others used vacuum distillation technology to volatilize and remove phosphorus in industrial silicon, which can reduce the phosphorus content to below 1ppmw. Dalian University of Technology and many foreign research institutions have used electr...

Claims

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Application Information

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IPC IPC(8): C01B33/037
Inventor 魏奎先马文会邹鹏谢克强王统周阳伍继君杨斌戴永年
Owner 四川纳毕硅基材料科技有限公司
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