Method for preparing elemental silicon

A technology of elemental silicon and silicate, applied in the field of metallurgy, can solve the problems of difficult to realize industrial production, high content of boron and phosphorus impurities, slow reduction speed, etc., and achieve the effects of cheap raw materials, high product purity and stable molten salt

Inactive Publication Date: 2011-02-23
WUHAN UNIV
View PDF4 Cites 19 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the carbothermal reduction method for producing crude silicon has serious pollution, high energy consumption, and high content of impurities such as boron and phosphorus. Electrolytic silicon smelting is a silicon smelting method with low energy consumption and low carbon emissions that may replace carbothermal reduction.
In 2003, Kyoto University Nohira and Ito

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

[0022] CaCl with 15wt% CaO at 950-1000°C 2 Dissolve 6wt% of SiO with a particle size of 0.1-20 microns in the molten salt 2 , with metal molybdenum as the cathode and graphite as the anode, the constant cathode current density is 200mA / cm 2 Electrolysis for 5 hours, add SiO in the middle of electrolysis 2 powder. After the electrolysis is complete, the cathode is taken out, washed with water and dilute hydrochloric acid to obtain elemental silicon powder.

Embodiment 2

[0024] CaCl at 850-1000°C 2 Dissolve 10wt% of CaSiO with a particle size of 1-50 microns in the molten salt 3 , with silicon rod as cathode and graphite as anode, constant cathode current density 200mA / cm 2 Electrolysis for 10 hours, add CaSiO in the middle of electrolysis 3 powder. After the electrolysis is completed, the cathode is taken out and placed in a vacuum induction furnace for smelting to obtain elemental silicon ingots.

Embodiment 3

[0026] CaCl at 600-800°C 2 -NaCl mixed salt is dissolved into 5wt% Na with a particle size of 0.5-30 microns 2 SiO 3 , with graphite as the cathode and graphite as the anode, the constant cathode current density is 20mA / cm 2 Electrolyze for 10 hours, add Na in the middle of electrolysis 2 SiO 3 powder. After the electrolysis is complete, the cathode is taken out, washed with water and dilute hydrochloric acid to obtain elemental silicon powder.

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 discloses a method for preparing elemental silicon. The method comprises the following steps of: dissolving SiO2 in an alkali metal or alkaline earth metal oxide-containing chloride molten salt, or dissolving alkali metal or alkaline earth metal silicate in the chloride molten salt, wherein the temperature of the chloride molten salt is 600 to 1,000 DEG C, electrolyzing by using graphite or silicon or a metal as a cathode and using graphite or an inert material as an anode to electrically deposit siliconic acid radicals at the cathode, and separating the electrodeposition to obtain the elemental silicon. In the method, the operation temperature is low; raw materials are cheap and available; the molten salt is stable; and the purity of the product is high. The process can be controlled through consistent current; continuous production is easy to be realized; the current efficiency is high; and the production energy consumption and cost of silicon can be obviously reduced.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and relates to a new method for preparing metal silicon. Background technique: [0002] Elemental silicon has very important applications in the fields of materials, information and energy, and its demand continues to expand with the development of the solar photovoltaic industry. At present, the carbothermal reduction method for producing crude silicon has serious pollution, high energy consumption, and high content of impurities such as boron and phosphorus. Electrolytic silicon smelting is a silicon smelting method with low energy consumption and low carbon emissions that may replace carbothermal reduction. In 2003, Kyoto University Nohira and Ito et al. (Nat.Mater.2003, 2, 397-401) reported that in CaCl 2 However, the serious ohmic polarization and concentration polarization in the solid-state cathode lead to slow reduction, and the cathode potential must be finely controlled, which is dif...

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): C25B1/00
Inventor 汪的华尹华意朱华甘复兴汪新
Owner WUHAN 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