Equilibria between Liquid Copper and Soda Slag

抄録

Equilibrium relations between liquid copper and sodium silicate slag or carbonate melt were investigated at 1523 K. The prominent feature in Cu₂O–SiO₂–(Na₂CO₃+Na₂O) slag is the existence of two miscibility gaps; one is between sodium carbonate and Cu₂O–Na₂O oxide, and the other between sodium silicate and Cu₂O. The solubility of copper in sodium silicate slag increases with increasing soda amount as well as oxygen potential, but extremely small solubility was observed in the carbonate melt. The activity coefficient of CuO_0.5 derived from the oxygen potential represents a minimum value at the slag composition of n_Na2O⁄n_SiO2=2. Sodium carbonate in slag decomposes nearly completely at the composition of 2Na₂O·SiO₂, 3Na₂O·As₂O₅ or 3Na₂O·Sb₂O₅.