The processes can comprise feeding a furnace with a raw material. These materials can contain impurities and valuable metals (base metals, precious metals, platinum group metals, minor metals). The processes can allow the volatilization of arsenic and indium contained therein. Before volatilizing the material, composition of the material is optionally modified so as to obtain a ratio % S/(% (Cu/2)+% Ni+% Co) of about 0.5 to about 2. The processes can comprise feeding a melting device with the depleted material, and with a source of carbon in order to obtain a multi-layer product and an off gas. Before melting the depleted material, the depleted material composition is optionally modified so as to obtain a ratio % S/(% (Cu/2)+% Ni+% Co) of about 0.5 to about 2. Thus, it is possible to recover Cu, Ni and Co as well as several other metals, including In, Ge, Pb, Bi, precious metals and platinum group metals.