Abstract: Process for desulphating a solid mixture and/or aggregate resulting from the breaking up of lead-acid batteries, comprising electrode slime containing lead compounds belonging to the group comprising oxides, oxidated compounds and sulphates, through contact with an aqueous solution of sodium carbonate and a substance dissolving lanarkite in which the said solid residues containing lead compounds are suspended, in which the solid phase of the suspension is subjected to a chemical reaction whose action is assisted by brushing, shear and compression forces exerted by brushing or scraping and compressing mechanical means, thus achieving almost total desulphatation.