System and method for purifying polysilicon through continuous slagging under electric field

A polysilicon and slag-making technology, which is applied in the field of high-purity polysilicon preparation system, can solve the problems of reduced purification effect, low production efficiency, energy waste, etc., to shorten the heating time of the cold furnace, high production efficiency, and reduce slagging agents The effect of dosage

Active Publication Date: 2012-10-17
上海太阳能电池研究与发展中心
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The continuity of this method is good, but during the purification process, a part of the silicon liquid with concentrated impurities needs to be recovered and purified, the production efficiency is low, there is a waste of energy, and the direct contact between the graphite electrode and the silicon liquid during the electromigration process will cause pollution. , reducing the effect of purification

Method used

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  • System and method for purifying polysilicon through continuous slagging under electric field
  • System and method for purifying polysilicon through continuous slagging under electric field
  • System and method for purifying polysilicon through continuous slagging under electric field

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Embodiment 1

[0027] See figure 1 with figure 2, a system for preparing high-purity polysilicon by continuous slagging under an electric field, including: a silicon material melting device 2 placed in a closed cavity 1, a slagging agent melting device 3, an electromigration device 5 placed in a heat preservation cavity 4, and slag liquid Collection tank 6 and silicon liquid collection tank 7. The silicon material melting device and the electromigration device are connected through the silicon liquid injection pipe 8, the slagging agent melting device and the electromigration device are connected through the slagging agent injection pipe 9, and the purified silicon liquid in the electromigration device passes through the silicon liquid overflow pipe 10 Flowing to the silicon liquid collection tank 7, the slagging agent after absorbing impurities in the electromigration device flows to the slag liquid collection tank 6 through the slag liquid overflow pipe 11. The silicon liquid injection ...

Embodiment 2

[0037] The slagging agent selects Na with a mass ratio of 4:1:5 2 O-CaO-SiO 2 For mixed molten salt, since the density of the slagging agent is smaller than that of the silicon liquid, it is necessary to use such as image 3 with Figure 4 The shown electrode is pasted on the slag liquid, and the silicon liquid is below the slag liquid. The mass ratio of the amount of slagging agent to silicon material is 1:5.

[0038] Firstly, a high-purity cathode graphite electrode plate 503 and an anode graphite electrode plate 504 are respectively arranged above the two regions of the electromigration cell, and wires are connected. The sealed cavity 1 is evacuated and the protective gas argon is introduced, and the pressure is maintained at 8000-20000Pa. Then add metal silicon material with a purity of 99.5% to the melting crucible 202 of the silicon material melting furnace through the silicon material adding hopper 203, and apply power to the intermediate frequency induction heating...

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Abstract

The present invention discloses a system and a method for preparing high purity polysilicon through continuous slagging under an electric field effect. The system comprises: a silicon material melting device arranged in a closed chamber, a slagging agent melting device, an electrical migration device arranged in a thermal insulation chamber, a slag liquid collection tank, and a silicon liquid collection tank. According to the method, a direct current electric field perpendicular to a silicon liquid flowing direction is applied on a slowly-flowing melting silicon liquid, a layer of the slagging agent is arranged between the electrode and the silicon liquid, the silicone liquid flows while impurities migrate to the electrode direction with the electric field effect, and the impurities contact the slagging agent, and then is subjected to a reaction to be absorbed. With the method of the present invention, the use amount of the slagging agent can be reduced, the purification effect can be increased, the purity requirement on the slagging agent can be reduced, and continuous production of the high purity silicon can be achieved. In addition, the method of the present invention has advantages of good purification effect, high production efficiency, small use amount of the slagging agent, and the like.

Description

technical field [0001] The invention relates to a system and method for preparing high-purity polysilicon, specifically a system for preparing high-purity polysilicon by continuous slagging under the action of an electric field, and a method for preparing high-purity polysilicon with the system. Background technique [0002] As a method for preparing solar-grade polysilicon, metallurgy has attracted more and more attention in recent years due to its advantages of low cost and less pollution. Slagging refining is an effective means of boron removal in metallurgy, and it is widely used in production. It is also very effective in removing Ca, Al, Ti and other metals that are more easily oxidized than silicon. Usually slagging and impurity removal is to make molten silicon liquid and Na2O-CaO-SiO 2 Wait for the slag phase to contact, and use the balanced distribution of impurities in the slag phase and silicon liquid to make the impurities enter the slag phase. The ratio of th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 褚君浩熊斌徐璟玉戴宁蒋君祥
Owner 上海太阳能电池研究与发展中心
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