Method for preparing solar-grade silicon material by melt-salt electrolysis method

A solar and molten salt technology, applied in the electrolysis process, electrolysis components, polycrystalline material growth and other directions, can solve the problems of equipment corrosion, no impurity removal, and low efficiency.

Inactive Publication Date: 2007-11-14
CENT SOUTH UNIV
View PDF0 Cites 40 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Molten salt electrolysis is one of the silicon material preparation methods, which can be divided into the following categories for the preparation of solar-grade polysilicon: (1) at a temperature higher than the melting point of Si, high-purity SiO 2 As raw material, polysilicon is prepared by molten salt electrolysis; the process temperature is high, energy consumption is high, equipment corrosion is serious, and it is difficult to obtain solar-grade polysilicon; (2) High-purity fluorosilicate is used as raw material to prepare

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] SiO with a purity of 99.46% 2 As raw material, its impurity content is Na 1000ppm, K 240ppm, Mg66ppm, Ca 490ppm, Fe 2000ppm, B 120ppm, Cu 20ppm, Ti 73ppm, Mn 200ppm, Ni 53ppm, other 52ppm; high-purity metal Cu is the cathode, and high-purity graphite is Anode with electrolyte composition of 48% Na 3 AlF 6 -32%AlF 3 -20%Na 2 SiF 6 , electrolysis temperature 850℃, current density 0.5A / cm 2 The silicon-containing alloy Si-Cu is electrolytically prepared under the conditions, and the silicon content is 15%.

[0012] The obtained silicon-containing alloy Si-Cu is used as the anode, the high-purity metal Al is used as the cathode, and the electrolyte composition is 70% K 3 AlF 6 -7%AlF 3 -15%BaF 2 -8%K 2 SiF 6 , electrolysis temperature 950℃, current density 0.5A / cm 2 The high-purity silicon-containing alloy Si-Al is electrolytically prepared under the conditions, and the silicon content is 40%.

[0013] Using high-purity silicon-containing alloy Si-Al as raw mat...

Embodiment 2

[0015] With a purity of 99.44% K 2 SiF 6 As a raw material, its impurity content is 0.5% of free acid (calculated as fluosilicic acid), 0.02% of fluoride, 0.02% of sulfate, 0.01% of iron, and 0.01% of heavy metal; high-purity metal Cu is the cathode, and high-purity graphite is the anode. Electrolyte composition 72.5% K 3 AlF 6 -10.5%AlF 3 -12%K 2 SiF 6 -5%CaF 2 , electrolysis temperature 900℃, current density 0.75A / cm 2The silicon-containing alloy Si-Cu is electrolytically prepared under the conditions, and the silicon content is 18%.

[0016] The obtained silicon-containing alloy Si-Cu is used as the anode, the high-purity metal Ca is used as the cathode, and the electrolyte composition is 67.5% K 3 AlF 6 -7.5%AlF 3 -8%K 2 SiF 6 -5%CaF 2 -12%BaF 2 , electrolysis temperature 920℃, current density 0.8A / cm 2 The high-purity silicon-containing alloy Si-Ca is electrolytically prepared under the conditions, and the silicon content is 6%.

[0017] Using high-purity ...

Embodiment 3

[0019] With 99.5% SiO 2 As raw material, its impurity content is Na 1120ppm, K 278ppm, Mg 75ppm, Ca 543ppm, Fe 2467ppm, B 136ppm, Cu 33ppm, Ti 78ppm, Mn 169ppm, Ni58ppm, other 43ppm; high-purity metal Zn is the cathode, and high-purity graphite is Anode with electrolyte composition of 69.5% Na 3 AlF 6 -6%AlF 3 -20%Na 2 SiF 6 -4.5%CaF 2 , electrolysis temperature 970℃, current density 0.5A / cm 2 The silicon-containing alloy Si-Zn is electrolytically prepared under the conditions, and the silicon content is 13%.

[0020] The obtained silicon-containing alloy Si-Zn is used as the anode, high-purity graphite is used as the cathode, and the electrolyte composition is 72% Na 3 AlF 6 -15%BaF 2 -5%CaF 2 -8%K 2 SiF 6 , electrolysis temperature 1425℃, current density 0.5A / cm 2 Electrolytic preparation under the conditions to obtain solar-grade polysilicon materials. Its purity is 99.999924%, including 0.03ppm iron, 0.027ppm aluminum, 0.063ppm calcium, 0.18ppm phosphorus, 0....

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention relates to a method for preparing the solar level polysilicon material, and specially relates to the method for using the craft of fusion electrolysis to three fluids fining and then to vacuum distillation to prepare the solar level polysilicon material. The invention first takes SiO2 or others compound of containing silicon as the raw material, and fusion electrolysis technology is adopted to prepare silicon containing alloy Si-M1. Three fluids fusion electrolysis fining technology is adopted to prepare high-purity silicon containing alloy Si-M2 with silicon containing alloy Si-M1 as anode and high-purity metal M2 as cathode. Finally, vacuum distillation technology is adopted to prepare solar level polysilicon material with high-purity silicon containing alloy Si-M2 as material. Compared with traditional Simens craft or improvement Simens craft, the invention has the superiority of high efficiency, low energy consumption, low cost, and low pollution.

Description

technical field [0001] The invention relates to the preparation of silicon materials, in particular to the preparation of solar-grade polysilicon materials by molten salt electrolysis-three-layer liquid refining-vacuum distillation. Background technique [0002] As a clean and sustainable energy source, solar energy has received extensive attention. High-purity polysilicon is the raw material used in silicon series solar cells. At present, the typical process for producing high-purity silicon at home and abroad is the Siemens process. More than 95% of the quartz ore is smelted into metallurgical-grade silicon at a high temperature of 1500°C in an electric furnace, and then smelted at a temperature of about 300°C and a pressure of 0.45MPa. Chlorination of metallurgical grade silicon to SiHCl with HCl 3 , followed by purification of SiHCl by rectification 3 , then use H 2 Reduced SiHCl 3 Electronic-grade silicon, and finally use electronic-grade silicon waste to manufactu...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C25B1/00C25C3/00C30B29/06C01B33/021
Inventor 赖延清田忠良张治安李志友刘芳洋李劼刘业翔
Owner CENT SOUTH UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap