Method for purifying industrial silicon through external refining

An off-furnace refining, industrial silicon technology, applied in the chemical industry, chemical instruments and methods, silicon compounds, etc., can solve the problems of small scale, low production efficiency, high production cost, and achieve low environmental pressure, high production efficiency, and operation. handy effect

Inactive Publication Date: 2012-07-18
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the problems of low production efficiency, high production cost and small scale, the purpose of the present invention is to

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0018] Example 1

[0019] Before the submerged arc furnace releases the silicon melt, a mixture of air and oxygen is continuously fed into the ladle, and then 2 tons of industrial silicon melt with a purity of 98% is released into the ladle, where it is heated, Heat preservation, so that the refining temperature outside the furnace of the silicon melt is controlled at 1700 ° C, and the simultaneous heating, silicon water discharge, and simultaneous refining are realized; and then 45% SiO is added directly to the ladle through the mouth of the ladle furnace and the ventilation pipe 2 +45%CaO+10%CaF 2 The mixed refining agent is used for slagging and refining, so that the ratio of slag to silicon is controlled at 10:1. With the continuous increase of the amount of silicon melt in the ladle, the flow rate of refining gas is adjusted to 60m 3 / h, the pressure is 5atm, refining outside the furnace for 1h; remove most of the metal impurities such as Al, Ca, Ti, Na and some non-meta...

Example Embodiment

[0020] Example 2

[0021] Before the submerged arc furnace releases the silicon melt, the mixed gas of water vapor, argon and nitrogen is continuously fed into the ladle, and then the silicon melt is released into the ladle, and heated and kept warm in the ladle to make the silicon melt The refining temperature outside the furnace of the body is controlled at 1450°C to realize simultaneous heating, outflow of silicon water, and simultaneous refining; then directly add 30% CaF to the ladle through the mouth of the ladle furnace and the ventilation pipe 2 +60%Al 2 o 3 +10%Na 2 The refining agent mixed with O is used for slagging and refining, so that the ratio of slag to silicon is controlled at 1:10. With the continuous increase of the amount of silicon melt in the ladle, the flow rate of the refining gas is adjusted to 10m 3 / h, the pressure is 2atm, refining outside the furnace for 4h; removing most of the metal impurities such as Al, Ca, Ti, Na and some non-metal impuriti...

Example Embodiment

[0022] Example 3

[0023] Before the submerged arc furnace releases the silicon melt, the refining gas and water vapor are continuously introduced into the ladle, and then the silicon melt is released into the ladle, and heated and kept warm in the ladle, so that the silicon melt can be refined outside the furnace. The temperature is controlled at 1600°C to realize simultaneous heating, silicon water discharge and simultaneous refining; then directly add the refining agent BaO to the ladle through the furnace mouth of the ladle and add the refining agent BaO to the ladle for slagging and refining, so that the slag-silicon ratio is controlled at 5︰1, with the continuous increase of the amount of silicon melt in the ladle, adjust the flow rate of the refining gas to 1m 3 / h, the pressure is 8atm, refining outside the furnace for 6h; removing most of the metal impurities such as Al, Ca, Ti, Na and some non-metal impurities such as C, B, P, S in silicon, this process can realize t...

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Abstract

The invention relates to a method for purifying industrial silicon through external refining, which comprises the following steps of: continuously introducing refined gas to a ladle before a submerged arc furnace releases a silicon melt to the ladle; then releasing the silicon melt into the ladle, heating in the ladle, controlling the temperature of the melt within a certain scope, adding a refining agent into the ladle for slag refining, adjusting the introducing flow rate, the pressure and the like of the refined gas along with the continuous increase of the quantity of the silicon melt in the ladle for external refining; and after the completion of the external refining, carrying out slag silicon separation and then pouring, i.e. the purification of the industrial silicon through the external refining is finished. Through the external refining process, a majority of metal impurities containing Al, Ca, Ti and Na and a part of B, P, S and C and other non-metallic impurities in the industrial silicon melt can be removed, and meanwhile, the effective components can be controlled for the subsequent purification of the industrial silicon, and high-quality raw materials are provided for solar grade silicon prepared by a metallurgical method. The method has the characteristics of full utilization, energy resource conservation, high production efficiency, less infrastructure investment, no environment pollution and the like.

Description

technical field [0001] The invention relates to a method for refining and purifying industrial silicon outside the furnace, in particular to a method for purifying industrial silicon by performing slagging and blowing refining on the silicon water just released from the submerged arc furnace in a ladle with a built-in heating system The method belongs to the technical field of preparing solar-grade silicon by purifying industrial silicon by metallurgical methods. Background technique [0002] According to the "Twelfth Five-Year Plan", my country will achieve the goal of "the proportion of non-fossil energy in primary energy consumption will reach 11.4% by the end of the 'Twelfth Five-Year Plan'". In the next few years, there will be a wave of investment in new energy industries such as solar energy. . At present, my country can only rely on the introduction of foreign improved Siemens process technology for small-batch production. The gap between the industrialization level ...

Claims

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Application Information

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IPC IPC(8): C01B33/037
CPCY02P20/10
Inventor 马文会魏奎先王统谢克强伍继君周阳杨斌戴永年
Owner KUNMING UNIV OF SCI & TECH
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