Process for producing solar grade polysilicon with sodium circulation method

Abstract

The invention relates to a process for producing solar grade polysilicon with a sodium circulation method. The process comprises the following steps: heating sodium fluosilicate Na2SiF6 to decompose to a silicon tetrafluoride (SiF4) gas and sodium fluoride NaF; vaporizing metallic sodium Na to a sodium (Na) steam at a high temperature; allowing the silicon tetrafluoride (SiF4) gas and the sodium (Na) steam to enter a reaction furnace to generate high purity silicon powder, allowing the high purity silicon powder to enter a first collector, and carrying out high temperature fusion to prepare finished products of polysilicon; allowing other mixed gases to enter a second collector, allowing sodium fluoride NaF to deposit with unreacted sodium Na, and carrying out heating separation on sodiumfluoride NaF and sodium Na; allowing the other gases to enter a third collector, cooling, collecting the residual silicon tetrafluoride (SiF4) gas, adding water to dissolve into a solution of fluosilicic acid (H2SiF6); and carrying out spray processing on residual substances. The process for producing solar grade polysilicon with the sodium circulation method, which has the advantages of simple production technology, no discharge of toxic gases, wide source and cheapness of raw materials, and accordance of the concept of Chinese circular economy, allows generated byproducts to be effectively utilized, the production cost to be substantially saved, and the development of the solar photovoltaic industry to be effectively promoted.

Description

technical field [0001] The invention relates to a process method for producing polysilicon, in particular to a process method for producing solar-grade polysilicon by a sodium circulation method. Background technique [0002] Due to the unparalleled environmental protection, low carbon, inexhaustible advantages of solar energy and the rapid development and new demand of the solar photovoltaic industry, there has been an upsurge in the development of low-cost, low-consumption solar energy and polysilicon in the world, and many specialized The new technology for producing solar-grade polysilicon, currently commonly used polysilicon reduction methods include Siemens method, silane method, fluidized bed method, etc. However, the existing polysilicon reduction method is high in cost, consumes a lot of energy, and pollutes seriously, which increases the production cost and environmental pollution. Contents of the invention [0003] In order to solve the problems existing in the...

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Problems solved by technology

[0002] Due to the unparalleled environmental protection, low carbon, inexhaustible advantages of solar energy and the rapid development and new demand of the solar photovoltaic industry, there has been an upsurge in the development of low-cost, low-consumption solar energy and polysilicon in the world, and many specialized The new technology for producing solar-grade polysilicon, currently commonly used polysilicon reduction methods include Siemens method, silane method, fluidized bed method, etc. However, the existing polysilicon reduction method is high in cost, consumes a lot of energy, and pollutes seriously, which increases the production cost and environmental pollution

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