De-tinning of flat copper material for tin and copper recovery

摘要

A de-tinning process for flat copper (alloy) material involves: (a) deforming the material (8) to eliminate flat surfaces; (b) removing the tin coating by anodic dissolution and deposition on a cathode (12) in a bath (2) of strong alkaline solution; (c) interrupting anodic dissolution, after an experimentally determined time for removal of just the tin under given bath temperature and electrical conditions, by switch-off of the applied direct voltage and removal of the de-tinned material (8) and the tin-coated cathode (12); and (d) washing the de-tinned copper material. Preferably, anodic dissolution is carried out in a 5-15% aqueous caustic soda solution at 40-70 deg C, 3 V and 4500-6000 (preferably 5500) A.