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Technology And Theory Studies Of Upgrading Silver Recovery Of Flotation From Zinc Leaching Residues

Posted on:2003-01-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:G H ZhouFull Text:PDF
GTID:1101360125458058Subject:Mineral processing engineering
Abstract/Summary:PDF Full Text Request
In order to upgrade silver recovery of flotation from zinc leaching residues without affecting zinc metallurgical production of main production system, the new chemicals prescription of flotation based on the study of the new flotation collectors and mixed conditioners increases silver recovery from 50% to 84%. The new criterion of flotation reagents has been studied for better understanding structure-reactivity relation of flotation reagents. The theory of electrochemical Evans diagrams of sulphide mineral flotation system has been set up by means of the electrochemical principles and measurements of corrosion Evans diagrams and the electrochemical mechanism of flotation system of silver minerals has been elucidated. The main points of the paper read as follows:1. Silver recovery of flotation from zinc leaching residues raisedThe flotation technology of recovery silver from zinc leaching residues has been systematically investigated. Several kinds of new flotation collectors have been made and the effective new silver collector H-4 and conditioner NS-6have been developed. The locked cycle tests mainly based on collector H-4 and activator NS-6 demonstrate that silver concentrates grade are 0.45% at 84.5% Ag recovery.The flotation results clearly show that the new chemicals prescription of flotation has strong ability to resist Zn2+ effect and the Zn2+ in the silver concentrates obtained by the new chemicals prescription of flotation is less than the old's in the existing zinc plan. The new flotation technology don't change the nature pH of ore slurry and will not destroy the acid-base equilibrium of system of zinc metallurgical production. In addition, the chemicals ingredients of the new chemicals prescription will also not affect the zinc electrodeposition of electrolytic zinc production considering the composition and structure of chemicals. So, the new flotation technology has promising future for the industrial application.2. Flotation research of pure silver mineral studiedFlotation tests with synthetic silver minerals (chemically precipitated silver chloride, silver oxide and silver sulphosalt) and silver-doped sphalerite show that all the silver minerals and compounds can be readily floated with high recovery at pH< 5.5 at which silver recovery from zinc leaching residues by using sulphydrylcollectors. Zinc2+ activates the flotation of silver-doped sphalerite while depresses the flotation of AgCl, Ag2SO4 and Ag2O.3. The new criterion of minimum principle of absolute harness for flotation reagents put forthThe new criterion of minimum principle of absolute hardness for flotation reagents has been studied. The results show that the value between absolute hardness of collector, F, and absolute hardness of metal ion in mineral, m, is smallest, The reaction between collector and mineral first take place, that is min= F+ M By comparing with ksp criterion, radical electronegativity criterion xg and energy criterionEt, can symbolizes the ability of flotation collectors fixed on the surface of minerals and collector's electrochemical activity. When f is smaller, the collector is not only easily oxidized but also has high reaction activity on minerals. In addition,f is smaller, the corrosion electricity of sulphide mineral-collector is large. The new criterion min of flotation can be used to predict the flotation property of new collectors. The application of new criterion min in silver recovery of flotation from zinc leaching residues shows that collector H-4 can separate silver mineral, lead mineral from sphalerite.4. The theory of Evans diagrams of flotation system of sulphide mineral set upwith Evans diagrams of flotation system of sulphide mineral, not only the oxidizing rate of sulphide mineral, reaction rate of sulphide-collector but also the controlling factors of reaction rate can be explained clearly and directly. The electrochemical mechanism of flotation additives can also be analysed by the theory of the Evans diagrams.The relation of structures and properties of collectors ha...
Keywords/Search Tags:zinc leaching residues, flotation, collector, silver mineral, electrochemistry, corrosion
PDF Full Text Request
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