Study On Flotation Separation And Mechanism Discussion Of Complex Lead-zinc Polymetallic Sulfide Ore

The separation of lead-zinc polymetallic ore is one of the technical problems in the beneficiation work.On the one hand,the lead-zinc minerals are symbiotically inlaid,and dissociation is difficult;On the other hand,sphalerite is easily to be activated by unavoidable ion such as copper,lead and other ions,in the grinding process.Especially when the oxidation rate is high,the slime have important influence on separation flotation,which lower floating ability of two minerals.The process mineralogy of a complex polymetallic ore was studied.It showed that there were many kinds of minerals in the ore and elements of Pb,Zn could be recovered.The main lead mineral was galena and the main zinc mineral was sphalerite.With the characteristic of fine disseminated,closely combined with sphalerite,and high oxidation rate,the separation of galena from sphalerite was difficult.According to the nature of the ore and the perspective of economic use,the process flowsheet of preferential lead/zinc flotation was adopted.The result as follow;the grinding fineness of less than 0.074 mm accounting for 80%,the lead minerals were recovered by the flotation process of one roughing,three cleaning and one scavenging,using D₄₂₁ as collector,combined reagent of sodium pyrophosphate and sodium citrate as depressant,rough concentrate regrinding,then zinc minerals were recovered by the flotation process of one roughing,two cleaning and one scavenging,using CuSO₄ as activator,butyl xanthate as collector.In a closed circuit test,a lead concentrate were obtained with the lead grade of 60.34%and recovery of 81.31%,and the zinc content of 6.74%,a sphalerite concentrate was obtained with a grade of 47.86%Zn and recovery of 93.11%,and the lead content of 0.62%.The results shown that the combined reagent of sodium pyrophosphate and sodium citrate has strong restrain ability on sphalerite floatation.On the basis of actual ore research,pure minerals test were carried out.Galena and sphalerite have similar flotation ability,and flotation separation of galena from sphalerite cannot be realized by adding SPH or SCT alone,but the synergistic effect was obtained when the two reagents were used together,which has selective depression effect on sphalerite.The use of combined reagent of SHP and SCT as depressant can achieve the flotation separation of galena from sphalerite at pH 8 and the optimum ratio of SPH to SCT is 1:1.Through analyzing zeta potential,ions dissolved quantity and SEM-EDS images and flotation solution chemical calculation,mechanism action of combined reagents on galena and sphalerite were revealed.In this paper,through actual ore flotation test,pure mineral experiment and mechanism discussion,the combined depressant of sodium pyrophosphate and sodium citrate is proposed as a high-efficiency depressant for the flotation separation of complex lead-zinc polymetallic ore,and the flotation performance of the combined inhibitor is summarized.