Abstract: The present invention relates to method for treatment of residues originating from organochlorosilanes- and/or chlorosilane syntheses. The residues are, optionally together with an oxidation agent, supplied to a smelting furnace where the residues are melted in order to form a molten metallic phase comprising at least of silicon and copper and a slag phase, tapping of the metallic melt and an inert slag from the smelting furnace. Copper is dissolved from the solidified silicon-copper containing metallic phase by leaching with a mineral acid in order to produce a solid product substantially containing silicon, whereafter copper is recovered from the leach solution.