Technology Overview

The product is an intellectual property on innovative technological processes of producing silicon by alumothermic reduction of silica and its deep refining by synthetic slags, as well as ternary alloy route processes for obtaining of polysilicon of highest purity above 10N (99.99999999%), design services and organizing the relevant production. This product is of interest, first, to countries with no deposits of natural quartzite and coal, but with large resources of quartz sand, cheap aluminum and cheap energy.

Technology Features and Specification

Combined process for the production and purification of metallurgical silicon to the purity of 6N (99.9999%) and higher in an induction melting furnace is characterized by following advantages:

• high process speeds and low energy costs;
• obtaining cleaner recovery products compared to the carbothermic method;
• high boiling point of aluminum eliminates the loss of reducing agent for evaporation;
• simplicity and small dimensions of induction melting furnaces;
• environmental cleanliness of the metallurgical process.

Customer Benefits

• The costs of the ultra-metallurgical grade 6N UMG-Si as well as innovative ternary alloy CaAl2Si2 are about USD3/kg which are below 6N polysilicon spot prices.

Specific electricity consumption of inductive melting furnace is 4.95 kWh/kg for alumothermic reduction of silica, 1.4 to 2.3 kWh/kg for slag-assisted refining of 2N Mg-Si upto 6N and higher purity, and 1.4 kWh/kg for ternary alloy route processes for obtaining of polysilicon of highest purity above 10N.