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Purifying method of slag-making agent with boron removal

A technology of slag forming agent and slag liquid, which is applied in the field of solar-grade polysilicon purification, can solve the problems of high cost, no reuse of waste slag, expensive heating equipment, etc., and achieve the effect of low price and high density

Active Publication Date: 2015-07-08
福建上杭凯利碳素材料有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method has simple operation steps and can effectively reduce the boron content in silicon to below 0.2 ppm, the heating equipment used in this method is expensive, and the waste slag generated after slagging is not reused, resulting in high cost , not suitable for industrial mass production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1) Take 150kg of boron removal waste slagging agent and put it into the graphite crucible of the intermediate frequency furnace, turn on the smelting switch of the intermediate frequency furnace, adjust the power of the intermediate frequency to completely melt the waste slag into slag liquid, and keep the temperature of the slag liquid at 1700 ° C, wherein the waste slag is metal silicon CaO-SiO after slagging and boron removal 2 It is a high-boron waste slag; it is used as a slag-forming agent for metal silicon to remove boron, and its composition is as follows: CaO is 60%, and the rest is SiO 2 ;

[0035] (2) Add 60kg of quartz crucible fragments to the slag liquid in step (1), and fully contact with the slag liquid after heating and melting. The heating temperature is 1700°C; the quartz crucible fragments are high-purity quartz that has been used in polysilicon directional solidification furnace The crucible fragments are washed with clean water, dried, and crushe...

Embodiment 2

[0039](1) Take 200kg of boron removal waste slagging agent and put it into the graphite crucible of the intermediate frequency furnace, turn on the smelting switch of the intermediate frequency furnace, adjust the intermediate frequency power to completely melt the waste slag into slag liquid, and keep the temperature of the slag liquid at 1700 °C, wherein the waste slag is metal silicon CaO-SiO after slagging and boron removal 2 It is a high-boron waste slag; it is used in the slag-forming agent for metal silicon to remove boron, and its composition is as follows: CaO is 50%, and the rest is SiO 2 ;

[0040] (2) Add 80kg of quartz crucible fragments to the slag liquid in step (1), and fully contact with the slag liquid after heating and melting. The heating temperature is 1800°C; the quartz crucible fragments are high-purity quartz that has been used in polysilicon directional solidification furnace The crucible fragments are washed with clean water, dried, and crushed, and ...

Embodiment 3

[0044] (1) Take 200kg of boron removal waste slagging agent and put it into the graphite crucible of the intermediate frequency furnace, turn on the smelting switch of the intermediate frequency furnace, adjust the intermediate frequency power to completely melt the waste slag into slag liquid, and keep the temperature of the slag liquid at 1800 ° C, wherein the waste slag is metal silicon CaO-SiO after slagging and boron removal 2 It is a high-boron waste slag; it is used as a slagging agent for removing boron from metal silicon, and its composition is as follows: CaO is 55%, and the rest is SiO 2 ;

[0045] (2) Add 80kg of quartz crucible fragments to the slag liquid in step (1), and fully contact with the slag liquid after heating and melting. The heating temperature is 1800°C; the quartz crucible fragments are high-purity quartz that has been used in polysilicon directional solidification furnace The crucible fragments are washed with clean water, dried, and crushed, and ...

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Abstract

The invention discloses a purifying method of a slag-making agent with boron removal. The purifying method comprises the following steps of: melting waste slag-making agent with boron removal as slag liquid; putting chips of a quartz crucible into the slag liquid, heating and melting to enable the chips to be fully contacted with the slag liquid; adding titanium powder into the slag liquid, heating and melting to enable the titanium powder to be fully contacted with the slag liquid, wherein the heating temperature is 1500-1700 DEG C; after the reaction is finished, putting a graphite plate on the upper surface of the slag liquid after reaction to enable the graphite plate to be connected with a negative electrode of an external direct-current voltage and enable the graphite crucible to be connected with a positive electrode of the external direct-current voltage, applying the direct-current voltage on the graphite crucible, and electrifying for 30-60 minutes, thus obtaining slag liquid above 2 / 7-3 / 8 of the height of the slag liquid from the bottom part of the slag liquid, wherein the obtained slag liquid is the purified slag-making agent A with boron removal; and finally, pouring the remaining slag liquid into an insulating furnace, solidifying, grinding, carrying out acid washing, cleaning, and drying to obtain the purified slag-making agent B for removing aluminium in metal silicon. The purifying method disclosed by the invention has the advantages that the process is simple, repeated utilization of waste slag can be realized, the environmental-friendly effect is achieved and the cost is low.

Description

technical field [0001] The invention relates to the field of purification of solar-grade polysilicon, in particular to a method for purifying a boron-removing slagging agent. Background technique [0002] The energy crisis and the pollution of the environment by traditional energy have become the main restrictive factors for the development of society and national economy. In order to maintain sustainable development, countries around the world are actively adjusting their energy structure and vigorously developing renewable energy. New energy mainly includes solar energy, tidal energy, wind energy, and nuclear energy. Tidal energy has a large regionality; wind energy has low energy utilization rate and large regional differences; nuclear energy has a long cycle and is dangerous; and solar cells are safe to use and have a short energy recovery period due to their small size, light weight, long life, zero emissions, and reliable operation. , easy installation and the widest ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/037
Inventor 李伟生杨凤炳谢兴源龚炳生
Owner 福建上杭凯利碳素材料有限责任公司