Method for the treatment of residues from the zinc and lead production industry, with obtainment of exploitable products and secondary raw materials, according to the strategies of the circular economy

A method for the treatment of jarosite and other residues of the zinc and lead production industry, comprising the following steps:

• thermal treatment of the residues, at an increasing temperature from a minimum of 250° C. up to a maximum between 500° C. and 700° C., to obtain the evaporation of the imbibition water and the demolition of the jarosite molecule, resulting in the development of SO3 and in the removal of OH− groups to give additional water in the gaseous phase, and resulting in the obtainment, from the recondensation of these components, of an aqueous solution of diluted sulfuric acid, and with the simultaneous formation of a solid fraction composed of iron(III) oxide, zinc, lead, silver, copper sulphates and other minor elements;
• acid leaching of said solid fraction obtained from said thermal treatment step, by adding an acid leaching solution, to obtain an acid flow containing a solution of zinc, copper and silver sulphates, and a solid fraction enriched in iron oxides, lead sulphate and silver sulphate;
• saline leaching of said solid fraction obtained from said acid leaching step, to obtain a saline solution containing lead and silver and a solid fraction enriched in iron(III) oxide and containing silica;
• refining treatment of the saline solution containing lead and silver obtained from said saline leaching step;
• and
• purification of the silica of the solid fraction enriched in iron(III) oxide and containing silica obtained from said saline leaching step, by using an acid solution, to obtain
• solubilization of iron(III);
• separation of the solubilized iron(III) from the silica, which remains insolubilized;
• and
• precipitation of iron(III) to obtain iron oxide pigment.