PROCEDE HYDROMETALLURGIQUE EN VUE DE RECUPERER DU ZINC

A hydrometallurgical method of recovering zinc, copper and cadmium from their ferrites so that the ferrites are treated under atmospheric conditions in sulphuric acid bearing solution in the presence of potassium-, sodium- or ammonium-ions, is disclosed, in which the treatment takes place in one stage under such conditions that the non-ferrous metals, zinc, copper and cadmium, contained in the ferrites are transferred as sulphates to the solution and the iron is converted in the same stage to a solid basic iron salt by adjusting the sulphuric acid or ferric sulphate addition to be equivalent with regard to the ferrite amount fed into this stage and by adjusting the temperature to 80 DEG - 105 DEG C, preferably to 95 DEG - 105 DEG C, and further by adjusting the sulphuric acid content so that the total reaction takes place sufficiently quickly and after that the solid material is separated from the solution by washing it well with water and the solution and the wash water are returned to the neutral leaching stage.