| Copper-molybdenum ore is an important source of copper and molybdenum,and the main separation process is mixed flotation-copper-molybdenum separation process.Among them,"inhibiting copper and floating molybdenum" is the most commonly used method for the separation of copper and molybdenum.In the process of practical application,due to the similar floatability of copper and molybdenum and the residual collector on the surface of chalcopyrite,there are some problems in the separation process of copper and molybdenum,such as poor separation effect,large concentration of chalcopyrite depressant,serious environmental pollution and so on.In view of this,based on the inhibition characteristics of L-cysteine(L-CYS)on chalcopyrite,in order to reduce the concentration of NaHS,the application of combined depressant of NaHS and L-CYS in the flotation separation of copper-molybdenum mixed concentrate was investigated,and the depression mechanism of NaHS and L-CYS in copper-molybdenum separation was clarified,which provided a new idea for the research and development of high efficiency depressant of chalcopyrite in copper-molybdenum separation.Through single mineral flotation test and artificial mixed ore separation test,the depression effect of single use of NaHS and L-CYS and their combination was investigated.The results of single mineral flotation test show that when the concentration of fixed collector kerosene and foaming agent terpineol oil is 11 mg/L and 22 mg/L,respectively,the recovery of chalcopyrite and molybdenite is 9.68%and 73.38%respectively when the pH of pulp is 8 and the concentration of NaHS is 600 mg/L.When the pH of pulp is 6.7 and the concentration of L-CYS is 20 mg/L,the recovery of chalcopyrite is 8.81%and the recovery of molybdenite is 73.89%.When the pulp pH is 6.7,the mass ratio of L-CYS to NaHS is 1:30,and the concentration of combined depressant is 465mg/L,the recovery of chalcopyrite is 3.59%and the recovery of molybdenite is 64.18%.The separation results of artificial mixed ore show that the molybdenum concentrate with copper grade 3.06%,copper recovery 2.57%,molybdenum grade 53.17%and molybdenum recovery 74.68%can be obtained under the conditions of fixed kerosene and terpineol oil concentration of 11 mg/L and 22 mg/L,pulp pH of 8 and NaHS of 600 mg/L.When the pulp pH is 6.7 and the L-CYS concentration is 25 mg/L,the molybdenum concentrate with copper grade 6.05%,copper recovery 6.88%,molybdenum grade 44.27%and molybdenum recovery 71.56%can be obtained;when the mass ratio of L-CYS to NaHS is 1:30 and the combined depressant concentration is 310 mg/L,the molybdenum concentrate with copper grade of 2.52%,copper recovery of 1.98%,molybdenum grade of 54.44%and molybdenum recovery of 84.86%can be obtained.The results of the separation test of artificial mixed ore show that the combined depressant is more effective in the separation of artificial mixed ore composed of chalcopyrite and molybdenite,and the reagent concentration of NaHS can be reduced by nearly 50%when the separation index is similar.Chalcopyrite and molybdenite were pretreated in 20 mg/L butyl xanthate solution for 20 min,to investigate the effect of residual collectors on mineral surface on mineral depression.The results of single mineral flotation test show that when the concentration of kerosene and terpineol oil is 11 mg/L and 22 mg/L,and the pH value of pulp is 6.7,when the concentration of NaHS is 600 mg/L,the flotation recovery of chalcopyrite and molybdenite is 4.6%and 73.2%,respectively.When the concentration of L-CYS is 10 mg/L,the flotation recovery of chalcopyrite and molybdenite is more than 80%,and L-CYS loses its inhibition on chalcopyrite.When the mass ratio of L-CYS to NaHS is 1:30 and the concentration of combined depressant is 310 mg/L,the flotation recoveries of chalcopyrite and molybdenite are 3.53%and 82.2%,respectively.The study on the separation of artificial mixed ore shows that under the condition that the concentration of kerosene and terpineol oil is 11 mg/L and 22 mg/L,and the pH value of pulp is 7,when the concentration of NaHS is 600 mg/L,the molybdenum concentrate with copper grade 6.24%,copper recovery 6.55%,molybdenum grade 48.22%and molybdenum recovery 88.21%can be obtained.When the concentration of L-CYS is 50 mg/L,the molybdenum concentrate with copper grade 23.29%,copper recovery 85.59%,molybdenum grade 14.72%and molybdenum recovery 90.42%can be obtained.When the mass ratio of L-CYS to NaHS is 1:30 and the combined depressant concentration is 310 mg/L,the molybdenum concentrate with copper grade 4.56%,copper recovery 5.55%,molybdenum grade 47.08%and molybdenum recovery 83.02%can be obtained.The coarse separation test was carried out on the Cu-Mo bulk concentrate containing 23.70%copper and 3.36%molybdenum.The results show that when the pulp concentration is 30%,the pH value of the pulp is 6.7,the concentration of sodium silicate is 1.5 kg/t and the concentration of kerosene is 300 g/t,the combined depressant is 3.5 kg/t NaHS+350 g/t L-CYS,and the foaming agent is not added,the copper grade is 20.9%and the copper recovery is 13.57%.A molybdenum crude concentrate with a molybdenum grade of 15.3%and a molybdenum recovery of 70.08%.The open circuit test results show that the molybdenum concentrate containing 44.5%molybdenum,1.62%copper and 23.1%copper concentrate can be obtained by using combined depressant,cleaning and cleaning phase alone in the rough separation stage,and after one coarse,six concentrate and two sweeps,the molybdenum concentrate containing 44.5%and 1.62%copper and the copper concentrate containing 23.1%copper can be obtained.The results of Zeta potential,FTIR and XPS show that both NaHS and L-CYS can be chemically adsorbed on the pure chalcopyrite surface,which makes the chalcopyrite surface hydrophilic.When NaHS and L-CYS are used together,they can be adsorbed together on the chalcopyrite surface,thus making the mineral surface hydrophilic stronger.After the adsorption of butyl xanthate on the surface of chalcopyrite,L-CYS can not desorb the butyl xanthate on the surface of chalcopyrite,but it can be adsorbed together with butyl xanthate on the surface of chalcopyrite.Because the coverage rate of butyl xanthate on the surface of chalcopyrite is much higher than that of L-CYS,L-CYS can not inhibit chalcopyrite after adsorption of butyl xanthate.NaHS and butyl xanthate are adsorbed competitively on the surface of chalcopyrite.NaHS can desorb the molecular layer of butyl xanthate on the surface of chalcopyrite and make HS-adsorbed on the surface of chalcopyrite,thus making the surface of chalcopyrite hydrophilic.The inhibition principle of the combined depressant of NaHS and L-CYS on chalcopyrite after adsorption of butyl xanthate is as follows:NaHS desorbed the collector adsorbed on the surface of chalcopyrite at first,and then co-adsorbed with L-CYS on the surface of chalcopyrite,thus increasing the hydrophilicity of chalcopyrite surface. |
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