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Method for purifying industrial silicon by microalloying refining

A micro-alloying, refining and purification technology, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve the problems of high energy consumption, low efficiency, high cost, etc., to increase the specific surface area, realize multiple recycling, improve The effect of leaching rate

Pending Publication Date: 2021-08-13
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the slagging refining and electron beam smelting processes used to remove B and P impurities respectively have problems such as high energy consumption and low efficiency, which lead to long industrial silicon purification process cycle, high cost and unstable product quality.
At present, no effective way to simultaneously remove B and P impurities has been found

Method used

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  • Method for purifying industrial silicon by microalloying refining
  • Method for purifying industrial silicon by microalloying refining
  • Method for purifying industrial silicon by microalloying refining

Examples

Experimental program
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Effect test

Embodiment 1

[0032] 1) Micro-alloying refining: add flux (10% Cu+5% Sn) to industrial silicon for refining, mix industrial silicon and alloy powder evenly, place in a high-purity corundum crucible, and put it in a tubular atmosphere furnace. Raise the temperature to 1550°C at 5-10°C / min, keep it warm for 10h, then cool down to 750°C at 1-2°C / min, and then quench in an inert gas. Argon is selected as the inert gas in this embodiment.

[0033] 2) Wet leaching: ball milling the refined alloy sample to a particle size of 1-2 μm, using 3M HNO 3 +1M HF, solid-to-liquid ratio 1: (5-10) for pickling, temperature 50-80°C, magnetic stirring, pickling time 8h, then add 0.5MH to the solution 2 o 2 +2M HF for Cu-catalyzed pickling, temperature 50-80°C, magnetic stirring, pickling for 2-5h. The liquid is centrifuged to obtain high-purity silicon particles with a purity of over 99.999%. Among them, the removal rate of B impurities is 73%, and the removal rate of P impurities is 89%.

[0034] 3) Elect...

Embodiment 2

[0036] The technical solution in this embodiment is basically the same as that in Embodiment 1, except that the flux is composed of 10% Cu+10% Sn.

[0037] The prepared high-purity silicon particles have a purity of over 99.999%. Among them, the removal rate of B impurities is 69%, and the removal rate of P impurities is 70%.

Embodiment 3

[0039] The technical solution in this embodiment is basically the same as that in Embodiment 1, except that the flux is composed of 30% Cu+10% Sn.

[0040] The prepared high-purity silicon particles have a purity of over 99.999%. Among them, the removal rate of B impurities is 53%, and the removal rate of P impurities is 59%.

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Abstract

The invention belongs to the technical field of industrial silicon purification and refining, and particularly relates to a method for purifying industrial silicon by microalloying refining, which comprises the following steps: (1) adding Cu and Sn as composite flux into industrial silicon according to a specific proportion for microalloying refining; (2) crushing a refined alloy sample, then carrying out HNO3 and HF mixed pickling, after full reaction, adding HF and H2O2 into the pickle liquor to carry out catalytic pickling, and after catalytic pickling, carrying out solid-liquid separation to obtain high-purity porous silicon particles; and (3) adding electrodes into the acid leaching waste liquid for step-by-step electro-deposition, and recovering Cu and Sn in sequence, thus realizing recovery of flux metal. According to the method, the usage amount of flux metal is reduced through microalloying refining, combined adsorption of B and P impurities is achieved through a mixture phase in an alloy phase, catalytic pickling is carried out based on the characteristics of pickling waste liquid, the removal rate of the impurities is further increased, and effective recovery of the flux metal is achieved through an electrochemical deposition method.

Description

technical field [0001] The invention belongs to the technical field of industrial silicon purification and refining, and in particular relates to a method for refining industrial silicon by microalloying. Background technique [0002] The base material in silicon-based solar cells is solar-grade high-purity silicon (purity: 99.9999%), and its preparation cost accounts for more than 50% of the total cost of the cell. Therefore, in order to promote the sustainable development of the photovoltaic industry, research and development of low-cost, energy-saving and environmentally friendly solar-grade high-purity silicon preparation technology is one of the important tasks for improving efficiency and reducing costs of the photovoltaic industry during the "14th Five-Year Plan" period in my country. At present, the raw material used to prepare solar high-purity silicon is metallurgical-grade industrial silicon (purity 98-99%), which is obtained after smelting quartz ore in a submerg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
CPCC01B33/037
Inventor 黄柳青罗学涛冯铵淇池奇洲任婷婷许鹏飞
Owner XIAMEN UNIV