Research On Flotation Kinetics Of Copper-Bearing Minerals And Pyrite And The Action Mechanism With Reagents

Copper is a very important nonferrous material and plays an important role in the national economic construction.At present,the copper resources generally present the characteristic that the reserves and grad are low,and the distribution is relatively concentrated in China.Besides,most of the copper resources are imported from overseas.With the rapid increase of copper consumption,gradually reduce of copper sulfide ore and copper-rich ore in China,the development of new flotation technology based on the characteristic of copper ore thus enhancing the utilization of the complicated and refractory copper ore is very important for the sustainable development of copper industry.Based on this,the rule of the floatability and flotation rate of four copper-bearing minerals which were chalcopyrite,bornite,digenite,malachite,and pyrite was systematically summarized,and the interaction mechanism about the flotation reagents and mineral surface was studied in this paper,which is of great theoretical and practical significance for improving the separation result and the exploitation of copper resources.The results of the study on flotation kinetics of single mineral showed that the floatability of copper sulfide minerals was similar with the cumulative recovery were all above 90%,and the flotation rate of digenite was higher than that of chalcopyrite and bornite,but the floatability and flotation rate of pyrite is the worst when using CaO as the regulators with the value of pH was 11.40,the dosage of sodium butyl xanthate(SBX)was 1×10-4mol/L.When digenite and pyrite were oxidized for 120 days,the floatability and flotation rate became worse,while the high dosage of Na2S could restore the the floatability and flotation rate of digenite.The floatability and flotation rate of malachite in this study was worse,in the optimum test condition,the cumulative recovery and the value of K was 55.52%and 0.47,respectively.Three kinds of first-order flotation kinetic models were used for the fitting analysis of the flotation results of four copper-bearing minerals and pyrite.The results showed that the applicability and goodness of fitting of the classic first-order flotation kinetic models was better.Based on this,the change rule of the value of K and R? under different flotation conditions was studied.The results indicated that the change rule of the value of K and R? was not always consistent,and the flotation index could not be evaluated only by one parameter.Besides,the influence of particle size on the copper sulphides and malachite was the largest.While the improved flotation kinetic parameters Km and SI could better predict the separation trend of copper sulfide minerals.Back-propagation(BP)neural network could be used to predict the flotation results of the sulphide minerals and malachite,the value of R2 of the cumulative recovery and flotation rate constants were all above 0.90 for sulphide minerals,and the value of R2 of the cumulative recovery and flotation rate constants for malachite were 0.9973 and 0.9860,respectively.The classic first-order flotation kinetic model was also applicative for the fitting analysis of the separation of binary mixed minerals,the value of R2 were all above 0.99.Based on this,the parameter of SE(t)could be used for evaluating the separation results.The results showed that the separation efficiency of digenite was the best,and the parameters of t95 and t99 could be used to predict the optimum flotation time.The results of the study on the flotation kinetics of the interaction between minerals in binary system indicated that fine-grained minerals had an impact on the floatability and flotation rate of coarse-grained minerals,for heavily oxidized pyrite,the addition of finegrained digenite could improve its floatability and flotation rate.When the content of digenite was 10%,the recovery of pyrite was 90.14%,and the value of K was 0.80 min-1.Based on the results of single mineral flotation,asynchronous flotation tests of binary and polynary mixed minerals were carried out.The results showed that the unoxidized and oxidized sulphide minerals,and malachite with different floatability and flotation rate could be treated at low alkaline conditions during the first stage of rougher flotation.As for the concentration after roughing,the selective separation of Cu-S ore could be carried out at high alkaline conditions using CaO as the inhibitor.As for the tailings after roughing,the addition of Na2S could be used to recovery digenite oxidized for 120 days and malachite.The results of research on the action mechanism of reagents on the surface of the minerals indicated that the measured contact angle of the minerals surface after treated with SBX or Ca2+could intuitively reflect the difference of the flotation rate of different minerals.When digenite was heavily oxidized,the zeta potential of the surface increased by a large margin is mainly due to the reason that large amounts of copper oxides and hydroxides generated.The floatability and flotation rate of heavily oxidized digenite could be restored after the addition of Na2S and SBX mainly because that these two agents lower the quantity of hydrophilic copper sulphate and oxides/hydroxides on the surface of digenite,thus making the surface contact angle increase to 98.6°,decreasing the amount of SBX adsorbed to the value observed for unoxidized digenite.When pyrite was heavily oxidized,the zeta potential of the surface increased by a large margin is mainly due to the reason that large amounts of ferric oxides/hydroxides generated,and re-adsorbed on the surface in solutions.When 10%of digenite was added,the floatability and flotation rate of heavily oxidized pyrite could be restored mainly because fine-grained digenite particles masked on the surface of coarsegrained pyrite particles.Besides,the fine-grained oxidation products on the surface of pyrite decreased significantly.This study provided fundamental basis for improving and developing new flotation technology of copper-bearing minerals,and was important for the recovery of copper sulfide from oxidized Cu-S ore.Besides,this study enriched the fundamental theory about the flotation of digenite.