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US 7,604,785 B2Granted
Process for the recovery of elemental sulphur from residues produced in hydrometallurgical processes
AssigneeEngitec Technologies S.P.A.
InventorsMarco Olper, Massimo Maccagni, Silvano Cossali
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Abstract
The present invention relates to a process for the recovery of elemental sulphur from residues produced in hydrometallurgical processes based on leaching with a solution of sodium sulphide in which the sulphur contained in the residues is selectively leached as sodium polysulphide. The sulphur leaching solution is conveniently regenerated and recycled to the process.
Claims12
A process for the production of elemental sulphur from residues produced in hydrometallurgical processes comprises:
- a) leaching of residues containing sulphur with a solution of sodium sulphide wherein the sulphur contained in said residues is selectively leached as sodium polysulphide;
- b) separation of the residues from the solution containing polysulphide;
- c) treatment of said solution containing polysulphide with CO2 to obtain a dispersion containing elemental sulphur, acid sodium polysulphide and sodium bicarbonate;
- d) separation and recovery of the elemental sulphur from the solution containing acid sodium polysuiphide and sodium bicarbonate;
- e) treatment of said solution of acid sodium polysulphide and sodium bicarbonate with CaO for regenerating the leaching solution;
- f) separation of a residue of CaCO3 from a solution of sodium sulphide which is recirculated to phase a) of the process.
3 more elements
Dependencies are inferred from the claim text.