Abstract:
Hardhead is a tin-iron alloy formed during tin smelting process which is recycled in the smelting circuit. Extraction of tin from hardhead can be done by leaching with hydrochloric acid. The leaching parameters investigated are stirring rate of 200-800 rpm, temperatures of 40-70 ℃, HCl concentration of 1-4 M, hardhead/acid solution of 5-20 g/100ml, hardhead particle sizes in the range of -65 to +200 and -270 mesh and leaching time up to 6 hours. Tin and iron in hardhead dissolved in hydrochloric acid as tin chloride and iron chloride. For hardhead containing 46.31% Sn and 41.49% Fe with -270 mesh size, tin was completely leached out whereas 77.85%of Fe was extracted at 70 ℃, 3 M HCl, 15 g/100ml hardhead/acid solution within 6 hours. The separation of tin from the leached solution was done by pH adjustment with NaOH. At pH 3.0, 97.68% of tin was recovered as tin hydroxide precipitate while iron remained in the solution.