Abstract: In a high-arsenic tungsten-tin polymetallic ore from Inner Mongolia,the contents of Cu,Pb and Zn are 0.25%,0.31% and 1.10%,respectively,with As content as high as 1.54%.The arsenic-bearing mineral (arsenopyrite) is closely intergrown with metal sulfides,making the separation difficult.To avoid the negative impact of sulfide minerals on the subsequent tungsten-tin separation and to achieve comprehensive recovery of associated Cu,Pb and Zn,a flotation desulfuriza tion process was investigated based on process mineralogy.The results show that by adopting the process flowsheet of bulk flota tion of copper-lead-zinc-arsenic sulphide minerals under weakly acidic conditions,followed by separation of arsenic from the copper-lead-zinc bulk concentrate and then separation of copper from lead-zinc,and after reagent-removal treatment,the com bined depressant of lime + sodium humate + bleaching powder can effectively depress arsenopyrite at low alkalinity,achieving efficient separation of copper-lead-zinc from arsenic.After arsenic removal,the copper-lead-zinc bulk concentrate is treated with zinc sulfate + sodium sulfite + CMC to depress lead and zinc,thereby separating copper from lead-zinc.The closed-circuit test produced a copper concentrate with a Cu grade of 17.78% and Cu recovery of 63.51% (containing 0.77% As),a lead zinc bulk concentrate with Pb grade of 15.22% (Pb recovery 67.65%) and Zn grade of 41.04% (Zn recovery 71.94%,con taining 0.81% As),and an arsenic concentrate with As grade of 22.15% and As recovery of 91.11%.The desulphurization tailings (feed for subsequent tungsten-tin recovery) have their Cu,Pb,Zn,and As contents reduced to 0.03%,0.04%, 0.09%,and 0.14%,respectively,while the WO3 grade is 0.17% and Sn grade 0.21%,with WO3 recovery of 96.97% and Sn recovery of 85.67%,thus creating favourable conditions for the subsequent recovery of tungsten and tin.

Key words: copper-lead-zinc,polymetallic sulfide ore,high arsenic,combined depressant,bulk flotation,comprehensive recovery