Untitled research work

Both natural ores having mineral assemblages of chalcopyrite-monoclinic pyrrhotite and of cubanite-chalcopyrite-hexagonal pyrrhotite were heated in evacuated glass tubes to measure sulfur fugacity at temperatures from 300° to 450°C by electrum-tarnish method. The values of sulfur fugacity were also reconfirmed by pyrrhotite indicator method using chemical composition of coexisting pyrrhotite after heating. They obtained by both methods were in good accordance. According to the results of the experiments, the ore containing cubanite showed lower sulfur fugacity values than the ore not containing one. It suggests that eubanite has been formied under a lower sulfur fugacity condition. By the heating experiments, the tie line change of mineral assemblages from chalcopyrite-pyrrhotite to intermediate solid solution-pyrite was found at 350°C.