Process for the preparation of silicon or ferrosilicon

US4435209A · kind A · utility

Assignee

• KemaNord AB · SE

Inventor

• Thomas Johansson · Örebro, SE

Key dates

• Filing date: Mar 31, 1982
• Grant date: Mar 6, 1984
• Expiry date: Mar 31, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C35/005
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process for the production of silicon or ferrosilicon by reduction of silicon oxide, optionally in the presence of iron or iron oxide, using a carbonaceous reducing agent, in a reduction furnace. The yield is improved without harmful temperature rises if the ratio of the amount of thermal energy supplied to the furnace to the amount of silicon oxide supplied to the furnace is made adjustable in such a manner that a value for the ratio can be set within an interval, which interval in its lower end is limited by the lowest value permitting constant reduction of the silicon monoxide and silicon directly with a certain part of the reducing agent which is supplied at the top of the furnace, because the amount of produced silicon monoxide is insufficient for complete conversion of all the carbonaceous reducing agent to silicon carbide at the top of the furnace, and in its upper end is limited by the highest value permitting constant reduction of the silicon oxide raw material to silicon monoxide and silicon directly with silicon carbide, because the amount of produced silicon monoxide is sufficient for conversion of the carbonaceous reducing agent to silicon carbide at the top of the f…