Outokumpu Oy

Asko Parviainen

Bror G Nyman

Stig-Erik Hultholm

Sigmund P Fugleberg

Jussi K Rastas

A process for the recovery of valuable metals from metallic alloys having iron as their principal constituent is disclosed in which the metal is leached by means of a sulfuric acid solution having such a concentration that a nearly saturated salt solution is obtained, and after the separation of a possible leach residue the solution is heated close to the boiling point, at which time an acid solution is added in an amount corresponding to the salt which has passed out of the solution, in order to crystallize the salt mixture, the crystallized material is separated from the solution and is decomposed under sulfating conditions, whereafter the metal salts are leached out from the iron oxide by means of water.

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Espoo, Finland

Asko Parviainen