Method and equipment for purifying polycrystalline silicon through solidification crucible rotary electron beam melting

Abstract

The invention belongs to the technical field of physical metallurgy technological purification, and in particular relates to a method and equipment for purifying polycrystalline silicon through electron beam melting. A high-phosphorus silicon material is molten through electron beams under the vacuum condition to obtain low-phosphorous molten silicon, and the low-phosphorous molten silicon is poured into a solidification crucible to be solidified; the processes of charging, smelting and purifying and pouring are repeated until the solidification crucible is fully loaded; another hollow solidification crucible is rotated below a molten liquid pouring port, and the processes of charging, smelting and purifying and pouring are repeated until the solidification crucible is fully loaded; and the processes of fully charging one solidification crucible and rotating another hollow solidification crucible below the molten silicon pouring port are repeated until all the solidification crucibles are fully loaded, and after the low-phosphorous molten silicon in all the solidification crucibles is solidified, ingots are taken out. By the method, the whole purifying time of a plurality of times of smelting is reduced, and the times for vacuumizing and preheating of electron guns are reduced, so that the production efficiency is increased; and the equipment is compact in structure, is easy to operate, is safe and controllable and has high production efficiency.

Description

technical field [0001] The invention belongs to the technical field of purifying polysilicon by physical metallurgy technology, in particular relates to a method for purifying polysilicon by electron beam smelting, and also relates to its equipment. Background technique [0002] Solar-grade polysilicon material is the most important photovoltaic material. It is used in solar cells and can convert solar energy into electrical energy. In today's shortage of conventional energy sources, solar energy has huge application value. In recent years, the global solar photovoltaic industry has grown rapidly. Solar cells The rapid increase in output has directly driven the sharp expansion of polysilicon demand. However, the high manufacturing cost and complex manufacturing process of solar-grade polysilicon materials are the bottlenecks restricting the development of the photovoltaic industry, which seriously hinders the promotion and use of solar cells in my country. my country's ...

AI Technical Summary

Problems solved by technology

Electron beam smelting technology is one of the important methods in the metallurgical preparation of solar-grade polysilicon. It is a process that uses high-energy-density electron beams as a melting heat source. The general electron beam smelting method is to form a molten pool by melting bulk silicon materials. Finally, under the high temperature generated by the electron beam, the surface evaporation effect is used to effectively remove impurities with high saturated vapor pressure such as phosphorus and aluminum. , take out the solidified ingot, and then carry out the next smelting, so that the vacuum of the extraction chamber and the electron gun preheating must be repeated, which not only increases the time of multiple smelting, but also increases energy consumption, such as power and equipment loss etc., resulting in a reduction in production efficiency. At the same time, in the previous electron beam melting polysilicon process, continuous feeding and continuous discharging could not be realized, which increased production costs and was not conducive to industrial production.

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