Experimental Research On Hot-air Sulfidation Roasting And Flotation Of Lead-zinc Oxide Ore

Currently,people pay more and more attention to the exploitation of refractory lead-zinc oxide ore,but the effect of conventional flotation is far from satisfactory.To enhance the refractory lead-zinc oxide ore’s utilization,Changsha Research Institute of Mining and Metallurgy Co.,Ltd,has made lots of researches.Among them,the technology of sulphidizing roasting-separation technology has achieved a relatively satisfactory laboratorial index.However,because of limitation of sulfidation roasting device,the technology cannot be applied into industry.Therefore,it’s urgent to develop an appropriate device for sulfidation roasting of lead-zinc oxide ore.First of all,according to the parameter calculation result and design of small-scale coal-based hot air equipment,an external combustion device was studied and developed.Then,the content of CO,CO2 and N2 in equilibrium vapor was obtained after thermodynamic analysis and calculation of coal’s combustion in the external combustion device;the device’s temperature increasing characteristics could be determined by coke’s combustion experiment in the device;and the control method of combustion temperature and combustion rule of coke dosage were studied through coke dosage combustion test and blast volume combustion test.Meanwhile,another combustion test was conducted with bituminous coal as the fuel in the external combustion device,to investigate the similarity and distinction of combustion rule between bituminous coal and coke.Besides,the thermal balance in the external combustion device was calculated and the results showed that when reducing atmosphere was produced in the device,coke’s actual combustion amount was 1222g,while un-burnt rate of coke was 25.31%.Finally,sulfidation roasting test of lead-zinc oxide ore was carried out in the above developed device,then the roasted ore was processed flotation test.The effect of sulfidation roasting was judged by flotation result.The tests results indicated that a best roasting result could be got when the lead-zinc oxide ore was roasted under 750℃for one hour by controlling neutral or reducing atmosphere.At last the mixed flotation closed circuit test result showed that a concentrate with grade of lead and zinc 8.72%and 34.02%could be obtained,and the recovery of lead and zinc were 79.71%and 78.98%,respectively.It’s obvious that these roasting results in the developed device coincided with the best roasting results in muffle furnace.