Method for recovering zinc from zinc-containing waste materials

Abstract

The present invention relates to a method for recovering zinc from zinc-containing materials, especially from zinc-containing materials recovered from waste gases in metallurgical smelting processes. Particulate zinc-containing materials are agglomerated together with a carbonaceous reduction material and optionally slag forming materials, and are supplied to a gas tight closed electrothermic smelting furnace containing a molten bath kept at a temperature between 1200.degree. and 1700.degree. C. in which the agglomerates are smelted and subjected to selective reduction and volatilization of zinc and other volatile metals. An inert slag phase and optionally a liquid metal phase are tapped from the smelting furnace, and zinc and other volatile metals are recovered from the waste gas from the smelting furnace by condensation. In order to prevent reoxidation of metallic zinc the particulate zinc-containing materials are agglomerated together with a carbonaceous binder which cracks at a temperature below 700.degree. C. and forms carbon black, and that the temperature in the gas atmosphere in the smelting furnace is kept above 1000.degree. C. in order to maintain a volume ratio between CO.sub.2 and CO in the gas atmosphere in the smelting furnaces below 0.3.

Dependencies are inferred from the claim text.