Electrolytic processes for the production of metallic lead from desulphurized lead pastel, and for desulphurization of a sulfur-containing lead pastel

摘要

The present invention relates to an electrolytic process for producing metallic lead starting from desulfurized lead pastel comprising the following operative phases: a) leaching the desulfurized pastel by putting it in contact with a solution comprising ammonium chloride, with the formation of a leach liquor and evolution of gaseous CO2; b) separating a first solid residue and a first clarified leach liquor from the leach liquor coming from phase a); c) leaching the solid residue separated in phase b) by putting it in contact with a solution comprising ammonium chloride and hydrogen peroxide; d) separating a second solid residue and a second clarified leach liquor from the leach liquor coming from phase c); e) joining the first clarified leach liquor coming from phase b) with the second clarified leach liquor coming from phase d) and forming a single solution; f) subjecting the solution leaving phase e) to electrolysis in a flow cell, with a current density ranging from 50 to 10,000 A/m2, said electrolysis resulting in the formation of a lead sponge. The present invention also relates to the relative desulfurization process of the pastel.