Phase relations and distribution of some minor elements in Cu-Fe-Sb system saturated with carbon at 1473 K

As a fundamental study to develop a new process for eliminating detrimental elements and for recovering valuable ones from secondary Cu-Fe base alloys with a considerably high content of antimony, both the phase relations in a miscibility gap of the Cu-Fe-Sb system saturated with carbon and the distribution of some minor elements such as silver, platinum, cobalt, nickel and sulfur between two phases in the miscibility gap were investigated at 1473 K by a quenching method. The phase separation into copper-rich and iron-rich phases occurred when the Cu-Fe-Sb system was saturated with carbon. The antimony content in the copper-rich phase was very large compared with that in the iron-rich phase, and carbon was mostly distributed in the iron-rich phase. Cobalt and nickel were distributed preferentially in the iron-rich phase and platinum and sulfur were distributed almost evenly in both phases, while silver mostly in the copper-rich phase. The experimental results for the phase separation and the distribution of the minor elements were discussed on the basis of activity coefficients in the copper-rich and iron-rich phases and were compared with the results for the Cu-Fe-As system saturated with carbon. By utilizing this phase separation, recovery of valuable silver and copper into the copper-rich phase and elimination of less valuable iron into the iron-rich phase are feasible for treating the secondary Cu-Fe-Sb base alloys