Method and device for efficiently and continuously smelting and purifying polysilicon with electron beams

Abstract

The invention belongs to the technical field of polysilicon purification with a physical metallurgy technology and particularly relates to a method for efficiently and continuously smelting and purifying polysilicon with electron beams. The method comprises the following steps of: forming a stable high-purity silicon smelting pool in a crucible with the electron beams; putting silicon powder to be purified into the smelting pool through a vacuum feeding gate, rapidly smelting and then smelting to remove phosphorous impurity in the silicon powder, wherein the obtained low-phosphorous silicon liquid periodically overflows from the crucible and forms a silicon block in a water-cooling inclined copper cell, and the silicon block drops to a collection barrel to be cooled; and finally carrying out continuous discharging through a vacuum discharging gate to finish the process flow of continuously purifying the polysilicon. In the invention, smelting ways of continuously feeding and continuously discharging are adopted, and the volatile phosphorus impurity with high saturated steam pressure can be removed by smelting the polysilicon with the electron beams, therefore, the aims of efficiently and continuously smelting and removing impurities are achieved, and the purify achieves the using requirement of solar grade silicon. The invention has the advantages of stable technology, low energy consumption, low cost and suitability for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of purifying polysilicon by physical metallurgy technology, and in particular relates to a method for removing impurity phosphorus in polysilicon by using electron beam smelting polysilicon powder technology, and the invention 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 hi...

AI Technical Summary

Problems solved by technology

The disadvantage of the Siemens method is that it adopts backward thermal chemical vapor deposition in the core link of the process. There are too many links in the process and the conversion rate is low at one time, which leads to a long process time and increases the cost of materials and energy consumption.

The known invention patent with application number 200810073986.X uses a vacuum electron beam melting furnace to achieve the purpose of purifying polysilicon, which consumes a lot of energy and has low efficiency. Can not realize continuous feeding and continuous discharging, this method has very big difference in principle and structure with the equipment proposed by the present invention

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