Thermodynamic Behavior of Tin in Primary/Secondary Smelting Systems Using Lime-Ferrite Slag

Copper producers which are aggressive in enhancing their recycling businesses have been facing an increase in the tin concentration of their feeds because the fastest growing business in the venous industry is the recycling of waste electrical and electronic equipment or E-waste which contains Sn-base solder alloy. Such business circumstances require technologies to make homogeneous slags even though those slags are extraordinary rich in tin, while avoiding the precipitation of both magnetite and refractory stannic oxide. Using lime-ferrite slag of the CaO–FeO_x–Cu₂O system has been a proven technology to avoid the precipitation of magnetite under any oxidizing atmosphere. The present paper, thus, experimentally determined the phase equilibria between the CaO–FeO_X–SnO_Y–Cu₂O system and molten copper under various oxygen pressures between 10^–9 and 10^–5 atm at 1250 and 1300 ℃. The results have been converted into the solubility of Sn in lime-ferrite slag and the distribution behavior of tin between the slag and copper. The present paper will also discuss the feasible copper smelting/converting operations with feeding plenty of tin into a copper smelting furnace.