ORALS

In order to recover gold from solid waste efficiently，a combined beneficiation and metallurgical test was carried out on gold-bearing tailings. The results of chemical analysis show that the gold content in solid waste is 0.86 g/t. Process mineralogy show that the main gold minerals are tellurite ore，tellurium-gold-silver ore and gold-bearing tellurium-silver ore，followed by natural gold and silver-gold ore. In the original ore sample，gold is mainly produced in the form of sulfide wrapped gold，accounting for 51.72%，followed by bare gold，accounting for 31.03%，a small amount of gold is produced in the form of quartz wrapped gold，accounting for 17.24%.The original ore sample was vibrated to the particle size of -0.074 mm accounted for 98.15%.According to chemical phase analysis，gold is still mainly produced in the form of sulfide wrapped gold，accounting for 50.00%，with little change. Part of gold is produced in the form of bare gold，accounting for 41.86%，and a small amount is produced in the form of quartz wrapped gold，accounting for 8.14%.It can be seen that grinding can obviously improve the leaching rate of gold. If gold is recovered by flotation，the recovery rate of gold can be increased. At the same time，it can also be seen that the recovery rate of gold is less than 50% by direct cyanidation leaching method，and the gold in the ore sample needs to be recovered by the combined process of concentration and smelting. The flotation gold concentrate pretreatment leaching process for gold concentrate should be adopted to recover gold. The closed circuit process of “one roughing-two sweeping-two cleaning” was adopted. Gold concentrate with the yield of 14.23%，gold grade of 5.21 g/t and gold recovery of 86.21% can be obtained. When the gold concentrate is grinded to -0.037 mm accounted for 70.12%，the leaching rate of direct cyanide gold is 41.60%.The main barrier effecting the gold leaching is that most gold is wrapped by pyrite and gold minerals are mainly tellurite，tellurite，gold-bearing silver tellurite，etc. The oxidizing roasting-leaching improved the leaching rate effectively. The suitable conditions for the oxidation roasting cyanidation leaching of gold concentrate are：The temperature of oxidation roasting is 750 ℃，the roasting time is 60 min，and the fineness of the roasting sand is -0.037 mm accounted for 85%，pulp concentration is 33%，pulp pH value is 10.5，sodium cyanide dosage is 10 kg/t，leaching time is 24 h. Under these conditions，the cyanide leaching rate is of gold is 73.76%，compared with the direct cyanide index of gold concentrate（cyanide leaching rate is 41.60%），the cyanide leaching rate of gold is increased by 32.16%.