Method for producing metal zinc

A method for producing metal zinc, comprising the steps of:

• a step for neutral leaching wherein a zinc-bearing solid raw material consisting of electric arc oven dusts, of impure zinc oxide obtained by a thermal method for volatilizing galvanization ashes, oxidized zinc ores or mixtures thereof undergoes neutral leaching with an aqueous solution, at a pH value maintained greater than 3.8 and less than or equal to 5, with formation of a suspension in which an aqueous phase contains a main fraction of the zinc of the raw material, which has passed into solution, and a solid phase contains a residual fraction of this zinc as well as antimony and other impurities, the step for neutral leaching comprising an addition of iron, as a soluble iron compound, into the suspension for contributing to coprecipitation of iron, antimony, and other impurities as well as maintaining oxidizing conditions in the suspension for causing oxidation of the iron and of antimony and said other impurities,
• a drawing-off step wherein said aqueous phase containing zinc in solution is drawn off from said suspension and exposing the zinc in solution to an extraction step, wherein the zinc in solution is extracted from the aqueous phase with an acid organic solvent, with formation of a zinc-loaded organic liquid phase and of an acid aqueous raffinate,
• an additional leaching step wherein the remaining suspension is leached after said drawing-off with an acid aqueous solution, at a pH value maintained below 3.5 and greater than or equal to 1, with formation of an aqueous pulp in which a liquid phase contains, solubilized, said residual fraction of the zinc of the raw material, iron, antimony, and other impurities,
• a step for introducing a neutralizing agent wherein a neutralizing agent is introduced into the liquid phase of this aqueous pulp with the obtaining of coprecipitation of iron, antimony, and other impurities,
• a solid/liquid separation in this neutralized pulp, with the obtaining of a zinc-bearing aqueous solution which is recycled to the step for neutral leaching the zinc-bearing solid raw material,
• re-extraction of the zinc from the zinc-loaded organic liquid phase, by means of an acid aqueous solution, and
• recovery of the re-extracted zinc from the acid aqueous solution by electrolysis.