Process Mineralogy of Low-Grade Double Refractory Gold Ore and Influencing Factor on Gold Leaching

The samples used were from a gold mine in Yunnan Province,which are all of the typical of low-grade double refractory gold ore containing 2.4 g/t Au,0.97 wt% As and 1.47 wt% C.The leaching rate of gold as a result of flotation concentrates and extraction by cyanidation is 10.43%,and it becomes 46.52% if the extraction process is roasting-cyanidation,which is thus referred to as extraordinary refractory gold ore in which the metallic minerals are mainly the pyrite and arsenopyrite and gangue minerals mainly cover the quartz,sericite,dolomite,calcite,illtie and clay mineral.Most of the occurrence state of gold in such a low-grade double refractory ore is invisible,i.e.mainly the inclusion gold or colloidal gold in sub-micro or super-micro state,the natural gold particles included in the pyrite and arsenopyrite crystals are the majority with electrum in minority.The influencing factors on low gold recovery are the inclusion gold,ore containing arsenic,carbonaceous matter and clay minerals.