Production technology and device for boron-removing and purification of polysilicon by adopting electromagnetic induction melting assisted with high-temperature plasma

Abstract

The invention discloses a poduction technology and a device for boron-removing and purification of polysilicon by adopting electromagnetic induction melting assisted with high-temperature plasma, andprovides a poduction technology and a polysilicon boron-removing and purification device which have low cost and high efficiency, are applicable to industrial popularization and adopt electromagneticinduction melting assisted with high-temperature plasma. The purification device is provided with a vacuum system, a mid-frequency induction melting system, a transferred arc plasma melting system anda pouring graphite mould. The technology comprises the following steps: putting the silicon metal into a crucible, vacuumizing, and heating and melting the silicon metal; increasing the power after melting to lead the liquid silicon temperature to be kept between 1600 DEG C and 1800 DEG C, starting the plasma melting system, declining a plasma gun above an arc initiating device, and introducing working gas for arc initiating; moving the arc initiating device off after arc initiating is finished, adjusting specified current and plasma arc length, after conducting plasma melting to the liquid silicon surface, zeroing the specified current, disconnecting the plasma arc, rising the plasma gun, turning off the air supply, pouring the liquid silicon into the mould, and taking silicon ingots outafter standing and cooling.

Description

Technical field [0001] The invention relates to a polycrystalline silicon boron removal and purification technology, in particular to a production process and a device for purifying polycrystalline silicon by using electromagnetic induction melting to assist high-temperature plasma boron removal and purification. Background technique [0002] Due to the energy crisis and traditional energy pollution to the environment, in order to maintain sustainable development, countries all over the world are actively adjusting their energy structure and vigorously developing renewable energy. Therefore, polycrystalline silicon solar cells have become a hot spot of global concern. Because the improved Siemens method for preparing high-purity polysilicon has a complicated process, high investment costs, chemical principles, and pollution problems, it is more practical to use metallurgy to purify solar-grade polysilicon. [0003] Among them, due to similar physical properties, how to effectively ...

AI Technical Summary

Problems solved by technology

[0009] The current industrial application of blowing slagging method has the following problems: First, the removal effect of B is still difficult to meet the requirements of solar-grade polysilicon

However, due to the use of non-transferred arc, its effective power is generally only 40% to 50% of the total power. Since the cathode and anode of the plasma arc are in the gun body, compared with the transferred arc plasma melting, although it does not require arc ignition operation, it consumes more energy. Large TV, complex equipment, expensive

At present, the biggest problem faced by the transfer arc plasma smelting is how to effectively strike the arc and realize large-scale industrialized continuous production in the actual operation process.

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