Abstract
Large quantities of brass scrap coated with lead-tin layer are accumulated due to manufacture failures of radiator tube reject. Separation of metal values from such material was studied. Scrap containing 55 copper, 25.5 zinc, 13.2 lead and 6.3% tin was completely leached with hot HCl solution containing small amounts of HNO sub 3 as oxidant. Upon cooling the leach solution, 61.5% of the lead content was precipitated as lead chloride. Tin was separated as hydrated tin oxide by treatment with ammonia solution. Copper was selectively separated by solvent extraction using aromatic oxime (Acorga PT- 5050Z) in kerosene and stripped by 3 M H sub 2 SO sub 4 in an aqueous solution which was crystallized to copper sulphate. Zinc and the remaining lead were recovered as zinc carbonate and lead hydroxide by precipitation with Na sub 2 CO sub 3 and NaOH respectively. The parameters affecting leaching and extraction processes such as time, temperature, acid and solvent concentrations were investigated. The results obtained revealed that valuable salts of the concerned metals were successfully separated after optimizing the conditions of leaching and separation processes. The optimum leaching conditions were achieved using 2.7 M HCl (equivalent to 1.35 acid: scrap stoichiometric ratio) and 0.96 M HNO sub 3 at 80 deg C for 1 h. The produced salts [PbCl sub 2 , SnO sub 2 bullet XH sub 2 O, CuSO sub 4 , ZnCO sub 3 and Pb(OH) sub 2 ] meet the standard specifications, are of economic value and find various applications in industry.