Slag forming mixt. for fire refining - comprises red mud, calcium hydroxide or oxide, and/or carbonate, and electrolytic sludge

摘要

In the fire refining of Pb- and Sn-contg. prim. Cu and/or Cu waste in a basic lined furnace, involving oxidative removal of Pb, Sn and other undesired impurities from the melt, 1-5% (based on the charge) of a slag forming mixt. of (by wt.) 30-70% red mud, 10-30% Ca (hydr)oxide and/or carbonate, 5-30% SiO2 and 0-30% electrolytic sludge are added to the melt. Slag forming mixt. is also described. The slag forming addn. may be pref. supplied to the melt surface or blown by a lance into the melt. ADVANTAGE - Process reduces the lining corrosion rate and the Cu content of the slag, while remaining inexpensive.