Method for treatment of zinc-containing by-products and waste materials

A method for the treatment of zinc-containing by-products and waste materials from the primary and second production of nonferrous metals, particularly zinc- and lead-containing slags from the production of lead. The by-products and the waste materials are supplied to a gastight closed electric smelting furnace in which the materials are melted and subjected to a selective metallothermic reduction in order to reduce and volatilise zinc and other volatile metals. Elemental sulphur and/or sulphur compounds are added to the smelting furnace in an amount sufficient to form a sulphide phase containing one or more of the elements Cu, Ni, Pb, As, Bi, Sb and Ag. An inert slag phase and the sulphide phase are tapped from the furnace, and zinc and other volatile metals are recovered from the off-gas from the furnace by condensation.