CN102267697B

CN102267697B - Process for producing solar grade polysilicon with sodium circulation method

Info

Publication number: CN102267697B
Application number: CN2010101980973A
Authority: CN
Inventors: 刘新林
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-06-04
Filing date: 2010-06-04
Publication date: 2013-01-02
Anticipated expiration: 2030-06-04
Also published as: CN102267697A

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 sodium fluoride 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

A kind of sodium circulation method is produced the processing method of solar-grade polysilicon

Technical field

The present invention relates to a kind of processing method of producing polysilicon, especially a kind of sodium circulation method is produced the processing method of solar-grade polysilicon.

Background technology

Because sun power has fast development and the newly increased requirement of impayable environmental protection, low-carbon (LC), the advantage such as inexhaustible and photovoltaic industry, the current upsurge that has formed in the world developing low-cost, low consumption sun power and polysilicon, emerge the new technology of many special production solar-grade polysilicons, the normal polysilicon reduction method that adopts has Siemens Method, silane thermal decomposition process, vulcanization bed method etc. at present, but, existing polysilicon reduction method cost is high, energy consumption is large, seriously polluted, increased production cost and environmental pollution.

Summary of the invention

The problem that exists in order to solve existing polysilicon reduction method, the present invention proposes a kind of sodium circulation method and produce the processing method of solar-grade polysilicon, this kind processing method adopts the chemical physics conversion method, production technique is simple, discharge without toxic gas, and the byproduct that produces effectively can be utilized, greatly saved production cost and energy consumption, effectively promoted the development of photovoltaic industry.

The technical solution adopted for the present invention to solve the technical problems is: the processing method that this a kind of sodium circulation method is produced solar-grade polysilicon is: with Sodium Silicofluoride Na ₂SiF ₆Put into reactor, with 300 ℃-800 ℃ temperature thermal degradation 1-5 hour, generate silicon tetrafluoride SiF ₄Gas and byproduct Sodium Fluoride NaF sell after Sodium Fluoride NaF cooling becomes solid; High purity metal sodium Na in reactor, is increased temperature 800 ℃-1000 ℃ and is vaporized into sodium Na steam; Make simultaneously silicon tetrafluoride SiF ₄Gas and high purity sodium Na steam enter Reaktionsofen by 1: 4 reaction formula weight than along pipeline, generate the high purity silica flour; The high purity silica flour enters the first collector, and the control temperature becomes piece with Powdered high purity silicon Si high-temperature fusion between 1000 ℃-1600 ℃, make the polysilicon finished product; Other mixed gas enters the second collector, at 800 ℃-100 ℃, makes Sodium Fluoride NaF and unreacted sodium Na deposition by the control temperature, and with Sodium Fluoride NaF and sodium Na heating and separating, sodium Na recycles again, and Sodium Fluoride NaF sells as byproduct; Other mixed gas enters the 3rd collector, cools to 10 ℃ of-0 ℃ of coolings, collects remaining silicon tetrafluoride SiF ₄Gas is dissolved in water into silicofluoric acid H ₂SiF ₆Solution is sold; Remaining material spray is processed.

The invention has the beneficial effects as follows: the processing method production technique that this a kind of sodium circulation method is produced solar-grade polysilicon is simple, discharge without toxic gas, raw material sources are extensively cheap, the concept that meets national recycling economy, and the byproduct that produces effectively can be utilized, greatly save production cost, effectively promoted the development of photovoltaic industry.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

Accompanying drawing 1 is that this a kind of sodium circulation method is produced the process flow sheet of the processing method of solar-grade polysilicon.

Embodiment

In accompanying drawing 1, the processing method that this a kind of sodium circulation method is produced solar-grade polysilicon is: with Sodium Silicofluoride Na ₂SiF ₆Put into reactor, with 300 ℃-800 ℃ temperature thermal degradation 1-5 hour, generate silicon tetrafluoride SiF ₄Gas and byproduct Sodium Fluoride NaF can sell after Sodium Fluoride NaF cooling becomes solid; High purity metal sodium Na in reactor, is increased temperature 800 ℃-1000 ℃ and is vaporized into sodium Na steam; Make simultaneously silicon tetrafluoride SiF ₄Gas and high purity sodium Na steam enter Reaktionsofen by 1: 4 reaction formula weight than along pipeline, generate the high purity silica flour; The high purity silica flour enters the first collector, and the control temperature becomes piece with Powdered high purity silicon Si high-temperature fusion between 1000 ℃-1600 ℃, make the polysilicon finished product; Other mixed gas enters the second collector, at 800 ℃-100 ℃, makes Sodium Fluoride NaF and unreacted sodium Na deposition by the control temperature, and with Sodium Fluoride NaF and sodium Na heating and separating, sodium Na recycles again, and Sodium Fluoride NaF sells as byproduct; Other mixed gas enters the 3rd collector, cools to 10 ℃ of-0 ℃ of coolings, collects remaining silicon tetrafluoride SiF ₄Gas is dissolved in water into silicofluoric acid H ₂SiF ₆Solution is sold; Remaining material spray is processed.

Impurity concentration＜the 0.02ppm (7N) of the silica flour that generates.

Fluoride for Raw Material water glass Na ₂SiF ₆, be the byproduct in the phosphate fertilizer making processes, the source is cheap and extensive; The byproduct Sodium Fluoride NaF that produces in the anti-process is the industrial chemicals of high-quality, is used for Aluminium industry and toothpaste production, silicofluoric acid H ₂SiF ₆Solution can be used for Metal plating, wood preservation, has disinfectant properties, can make the sterilizing agent in the brewage.

Claims

1. the processing method that the sodium circulation method is produced solar-grade polysilicon is characterized in that: with Sodium Silicofluoride Na ₂SiF ₆Put into reactor, with 300 ℃-800 ℃ temperature thermal degradation 1-5 hour, generate silicon tetrafluoride SiF ₄Gas and byproduct Sodium Fluoride NaF sell after Sodium Fluoride NaF cooling becomes solid; High purity metal sodium Na in reactor, is increased temperature 800 ℃-1000 ℃ and is vaporized into sodium Na steam; Make simultaneously silicon tetrafluoride SiF ₄Gas and high purity sodium Na steam enter Reaktionsofen by 1: 4 reaction formula weight than along pipeline, generate the high purity silica flour; The high purity silica flour enters the first collector, and the control temperature becomes piece with Powdered high purity silicon Si high-temperature fusion between 1000 ℃-1600 ℃, make the polysilicon finished product; Other mixed gas enters the second collector, at 800 ℃-100 ℃, makes Sodium Fluoride NaF and unreacted sodium Na deposition by the control temperature, and with Sodium Fluoride NaF and sodium Na heating and separating, Sodium Fluoride NaF sells as byproduct again; Other mixed gas enters the 3rd collector, cools to 10 ℃ of-0 ℃ of coolings, collects remaining silicon tetrafluoride SiF ₄Gas is dissolved in water into silicofluoric acid H ₂SiF ₆Solution is sold; Remaining material spray is processed.

2. the described a kind of sodium circulation method processing method of producing solar-grade polysilicon according to claim 1, it is characterized in that: sodium Na recycles.