Polycrystalline silicon self-plugging casting device

Abstract

The invention relates to equipment which is used for purifying solar-grade polycrystalline silicon by adopting a metallurgic method, and provides a polycrystalline silicon self-plugging casting device which can carry out casting through a casting channel at the bottom opening of a crucible. The polycrystalline silicon self-plugging casting device is provided with the casting channel, a heating system and a smelting crucible, wherein the heating system is arranged around the outer side of the casting channel, and the bottom of the smelting crucible is connected with the casting channel. The polycrystalline silicon self-plugging casting device can be applied to various silicon smelting processes including slagging, aeration, directional solidification, vacuum smelting and the like. The overturn casting manner is completely replaced, the continuous purification of various processes can be realized, meanwhile, the successful connection among various different smelting processes is also realized, the processes of uninterrupted solidifying and melting during the process of silicon smelting and purifying are reduced, the energy consumption is greatly saved, and more critically, the continuous production can be realized. The polycrystalline silicon self-plugging casting device has considerable market application prospects.

Description

technical field [0001] The invention relates to equipment for purifying solar-grade polysilicon by metallurgical methods, in particular to a polysilicon self-sealing casting device. Background technique [0002] In the metallurgical preparation process of solar grade polysilicon, a common step is 'casting'. Such as: Chinese patent CN101724900A discloses a slagging smelting device. The device is equipped with primary and secondary smelting crucibles. First, silicon and slag are mixed into the first smelting crucible and installed in the second smelting crucible. slag, then heat and melt the silicon slag mixture in the first crucible, stir and melt, and add BaCO 3 Make the slag phase sink to the bottom of the crucible, then turn the first crucible to the right and pour out the upper layer of silicon liquid to the second melting crucible for secondary slag melting, and then turn the first crucible to the left to make the crucible Pour the slag phase in the slag container. Af...

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Problems solved by technology

However, in addition to the same disadvantages as the Chinese patent CN101724900A, this invention is also used for vacuum smelting, and the volume of the entire furnace chamber will be increased by more than 3 times if the device is used for vacuum melting, making it difficult for the entire system to achieve high vacuum under high temperature conditions. The purpose of phosphorus removal

In addition, once silicon leakage occurs in the large-scale device of the purification device, it is easy to burn through the furnace shell, which may cause serious consequences such as explosion.

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