Caustic leaching of oxidised lead-zinc ores.

Fundamental aspects of the caustic leaching of oxidised lead and zinc ores are explored with a view to exploiting the considerable reserves of such materials in Italy and elsewhere. The laboratory study showed that satisfactory recoveries can be achieved though high temperatures and high concentrations of caustic soda are required. Carbonate minerals (smithsonite, hydrozincite and cerussite) are readily leached while silicate minerals (hemimorphite) require more stringent conditions due to the formation of colloidal silica which hinders dissolution. The possibility of selective recovery of the metals is discussed.
Fundamental aspects of the caustic leaching of oxidised lead and zinc ores are explored with a view to exploiting the considerable reserves of such materials in Italy and elsewhere. The laboratory study showed that satisfactory recoveries can be achieved though high temperatures and high concentrations of caustic soda are required. Carbonate minerals (smithsonite, hydrozincite and cerussite) are readily leached while silicate minerals (hemimorphite) require more stringent conditions due to the formation of colloidal silica which hinders dissolution. The possibility of selective recovery of the metals is discussed.