Abstract: Processes are provided for the autogenous production of crude lead from sulphidic lead concentrates or complex sulphide materials containing lead. The processes are carried out in a rotary converter with the rotation axis inclined to the plane of the vertical. In the process the sulphidic materials are smelted and reduced while the converter is rotated.

Abstract: The method of recovering liquid sulphur dioxide from gases containing sulphur dioxide by washing with water in an absorption plant and then stripping off absorbed sulphur dioxide at subatmospheric pressure. Water is removed from the stripped gasesby cooling and drying and sulphur dioxide is removed by condensation. The whole system is kept at a subatmospheric pressure by pumping off residual gases after the sulphur dioxide condensation.

Abstract: A process for the production of copper from raw materials containing sulphur, zinc and more than 0.2% Ni calculated on the copper content. The material is melted to matte and the matte converted to white metal, whereafter the white metal is converted to copper and the zinc present in the slag obtained from the matte is fumed off in a furnace therefore. The slag formed during the conversion of matte to white metal is removed and treated in a separate furnace with an amount of copper, iron or nickel sulphide material sufficient to lower the copper content to less than 2%, whereafter the treated slag obtained is charged to the slag fuming surface.