| Flotation is a common separation method for zinc ores.In the process of zinc ores flotation,a large number of metal ions were inevitably be introduced by slime,production water and grinding process.The dispersion and aggregation behavior of minerals was changed by adsorption of metal ions on the mineral surface,thus affecting the flotation effect of minerals.As a kind of zinc oxide ore,the flotation of smithsonite is always a difficult and hot topic.During the flotation of smithsonite,the dispersion of smithsonite and slime was affected due to the presence of unavoidable ions,thus affecting the process and selectivity of flotation.In order to analyzed the influence of unavoidable ions on the dispersion behavior of smithsonite and typical gangue minerals,smithsonite and calcite were selected in this paper,and cation valence state,pH,metal ion concentration and other conditions were systematically used to study the influence of dispersion behavior of smithsonite and calcite.The mechanism of metal ions on the dispersion behavior of smithsonite and calcite was studied by Zeta potential,mineral dissolution,metal ions adsorption tests and XPS,SEM-EDS analysis and DLVO theoretical calculations.The influence of metal ions on the dispersion behavior of smithsonite and calcite showed that the dispersion behavior of smithsonite and calcite were better under deionized water.However,when pH?10,hydroxyl complexes on the mineral surface were produced by dissolved Ca2+hydrolysis of fine calcite,which leaded to the phenomenon of aggregation and sedimentation and deteriorated the dispersion behavior of calcite.Different metal ions had different influences on mineral dispersion,the influence of monvalent metal ions on two kinds of minerals was less impact,but bivalent and trivalent metal ions was obvious.The precipitation phenomenon of mineral become more obvious with the increase of ions concentration.When ions reach a certain concentration,the turbidity of minerals tended to stabilize.The influence of metal ions on the surface properties of smithsonite and calcite showed that K+,Na+and Ca2+added,the positive and negative properties on Zeta potential of smithsonith was no significant change.Meanwhile,there had little effect of K+and Na+on the Zeta potential of calcite.When Mg2+and Fe3+added,smithsonite and calcite showed multiple zero electric points,indicated that ions changed the surface potential of the mineral.Metal ions adsorption tests and XPS analysis showed that Ca2+,Mg2+and Fe3+were adsorbed,and the adsorption capacity of smithsonite were Fe3+?Mg2+?Ca2+.Mg2+and Fe3+were adsorbed on Calcite,Fe3+was completely adsorbed and Mg2+was partially adsorbed.Accorded to the DLVO theoretical calculations of calcite,there was a potential barrier under the acidic conditions of Na+and K+.After the action of Mg2+,the total interparticle force was negative,and the coagulation phenomenon of particles was serious,indicated that the hydroxyl complexes and hydroxide were the main reasons for the change of mineral dispersion behavior.The influence of metal ions on the dispersion behavior of a single mineral was studied in this paper.This resulting conclusion offers the theoretic basis for adjusting the dispersion behavior of smithsonite and calcite.The paper contains 60 drawings,10 tables and 100 references... |
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