Hydrometallurgical method for treating valuable metal raw materials containing chlorides and fluorides
AssigneeOutokumpu Oy
InventorsSigmund P. Fugleberg, Jaakko I. Poijarvi
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Abstract
The purpose of the method is to remove chlorides and fluorides from a valuable metal raw material by leaching the raw material into sulphuric acid solution and by crystallizing the valuable metal sulphate selectively out of the solution. The valuable metal sulphate crystals are washed in sulphuric acid solution, and the recovered dechlorinated and defluorinated crystals are leached into water and conducted into electrolysis. The sulphuric acid solution employed in the raw material leaching and in the crystal washing is preferably the same as the return acid of the electrolysis. Chlorides and fluorides are removed from the mother liquor of crystallization in the bleed.
Claims1
A hydrometallurgical method for treating valuable metal raw materials containing chlorides and fluorides in order to recover valuable metals selected from the group consisting of Zn, Ni, Co, Cu, Mn, Mg and Fe, free from chloride and fluorides, for electrolytical removal, comprising leaching the valuable metal raw material containing chlorides and fluorides into a sulphuric acid solution, the major portion of which consists of the return acid obtained from the electrolysis, and selectively crystallizing only the valuable metal sulphate from the solution;
- washing the created sulphate crystals in the electrolysis return acid, and thereafter leaching the dechlorinated and defluorinated valuable metal sulphate crystals into water, and purifying the resulting solution and recovering the valuable metals though electrolysis;
- said chlorides and fluorides being removed in a bleed from the mother liquor of the valuable metal crystallization, and
- wherein sulphuric acid solution is fed into the bleed from the mother liquor crystallization stage to increase the sulfuric acid content thereof, and wherein chlorides and fluorides are removed from the bleed from the mother liquor of the crystallization by means of evaporating them in said increased sulphuric acid content and at an increased temperature.
Dependencies are inferred from the claim text.