Study On The Mechanism Of Selective Agglomerative Flotation Separation Of Fine Lead Salt And Iron Oxide In Iron Sintering Dust

Iron sintering dust is a kind of solid waste discharged in the sintering process in iron and steel plants.The content of valuable element Pb is about 2%～10%,and the content of Fe is 2～3 times that of Pb.Recycling these two resources will bring great environmental and economic benefits.The flotation separation effect of fine lead salts（Pb SO₄,Pb OHCl）and Fe₂O₃ is poor and the recovery rate is low in the treatment of iron sintering dust by traditional sulfide flotation.In this paper,a new route for selective agglomerative flotation separation of fine lead salt and iron oxide was proposed,that is,a new reagent combination of sulfate collector(C₁₂H₂₅SO₄Na)and highly selective inhibitor（fluorosilicate and phosphate）,and remarkable results have been achieved.The flotation test of pure minerals shows that the flotation separation of fine lead salt and Fe₂O₃ is favorable under weak acid condition,and the optimal flotation p H is 6.The inhibition order of the three inhibitors on Fe₂O₃ is sodium polyphosphate>sodium pyrophosphate>sodium fluorosilicate.The inhibition effect of sodium polyphosphate and sodium pyrophosphate on Fe₂O₃ is better.By Zeta potential test,FTIR test and XPS analysis,the selective agglomeration flotation separation mechanism of fine lead salt and Fe₂O₃by sodium pyrophosphate（Na₄P₂O₇）and sodium polyphosphate(Na₅P₃O₁₀)was studied.The results showed that the chemical adsorption of collector on the surface of the fine lead salt minerals exists,and there is an competitive adsorption between the inhibitor and collector.Through laser particle size test,optical microscope observation,scanning electron microscope observation,DLVO theoretical calculation and so on,it is found that SLS can selectively agglomerate fine lead salts and Na₄P₂O₇and Na₅P₃O₁₀ have selective dispersion effect on Fe₂O₃ mineral particles,and realized the selective agglomeration flotation separation of fine lead salt and iron oxide.This research is helpful to solve the recovery of lead and iron resources in iron sintering dust.