Abstract: A process for treatment of an acidic solution containing ferric iron and at least one non-ferrous metal, prior to removal of ferric iron therefrom, is characterized by adding a specified amount of at least one neutralizing agent, and separating off from the solution any residue or undissolved neutralizing agent remaining after neutralization, thereby producing a solution possessing an acid consuming capacity termed "negative acidity", and still containing substantially all the dissolved ferric iron in solution, and from which ferric iron can subsequently be removed with the generation of less acid compared to that generated from solutions partially neutralized according to the prior art.

Abstract: A process for treatment of lead residues, without prior sintering, in which residues more than 70% of the lead is present as lead sulphates, comprising addition of the said residues, together with a reductant containing carbon and together with fluxes that will react to provide a slag containing FeO, CaO and SiO.sub.2, directly to an electric furnace operating at a temperature of 1000 to 1500.degree. C in the slag layer to produce in the furnace a lead bullion. The expression "lead sulphates" will be understood to include lead sulphate and other compounds containing lead and the sulphate ion, for example, the basic lead sulphates.