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Abstract

A smelting process of superior energy efficiency, particularly suitable for the extraction of zinc, but also of lead and copper from raw materials comprising sulphide concentrates, and oxidized metalliferous materials, is carried out by establishing at least one oxidation zone and at least one reduction zone in a furnace, each zone comprising a slag bath and a gas space; the gas spaces of the oxidation and reduction zones being separated by a partition; feeding raw materials comprising metal sulphides, together with fluxes, to the or each oxidation zone, and feeding oxygen or oxygen-rich gas into the slag bath in the or each oxidation zone to oxidize metal compounds therein and produce an off-gas containing SO.sub.2 ; transferring metal-oxide-bearing slag from at least one oxidation zone to at least one reduction zone; introducing coal into the or each reduction zone to reduce metal oxides therein, and produce gases containing carbon monoxide and hydrogen; introducing a controlled stream of oxygen into the or each reduction zone, the amount of oxygen in the said stream being sufficient to partly post-combust carbon monoxide and hydrogen, thereby producing heat which is transferred back to the slag bath in the reduction zone, while leaving the gases sufficiently reduced to ensure that reduced metal is not re-oxidized; and recovering reduced metal from at least one reduction zone.

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First Claim