Synergistic activation of smithsonite with copper-ammonium species for enhancing surface reactivity and xanthate adsorption

Copper ions(Cu^(2+))are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology.The adsorption of Cu^(2+)and xanthate on the sulfidized surface was investigated in various systems,and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments.X-ray photoelectron spectroscopy(XPS)and time-of-flight secondary ion mass spectrometry(To F-SIMS)characterization demonstrated that the adsorption of Cu^(2+)on sulfidized smithsonite surfaces increased the active Cu—S content,regardless of treatment in any activation system.The sulfidized surface pretreated with NH_(4)^(+)-Cu^(2+)created favorable conditions for the adsorption of more Cu^(2+),significantly enhancing the smithsonite reactivity.Zeta potential determination,ultraviolet(UV)-visible spectroscopy,Fourier transform-infrared(FT-IR)measurements,and contact angle detection showed that xanthate was chemically adsorbed on the sulfidized surface,and its adsorption capacity in various systems was illustrated from qualitative and quantitative aspects.In comparison to the Na2S–Cu^(2+)and Cu^(2+)–Na2S–Cu^(2+)systems,xanthate exhibited a higher adsorption capacity on sulfidized smithsonite surfaces in NH_(4)^(+)-Cu^(2+)–Na2S–Cu^(2+)system.Hence,activation with Cu^(2+)–NH4+synergistic species prior to sulfidization significantly enhanced the mineral surface hydrophobicity,thereby increasing its flotation recovery.

Selective flotation of smithsonite from dolomite by using novel mixed collector system

A novel mixed collector (BHOA) was prepared by mixing benzohydroxamic acid (BHA) and sodium oleate (NaOL) and applied to the flotation separation of smithsonite from dolomite. Flotation results showed that NaOL alone had good collecting performance on smithsonite and common gangue mineral dolomite but had poor selectivity. By using a BHA/NaOL mixed system with a molar ratio of 2:1, the recoveries of smithsonite and dolomite reached approximately 90% and 5%, respectively. Surface tension analysis showed that the surface activity of BHOA was a little higher than that of a single NaOL because of synergistic effects. Zeta potential and X-ray photoelectron spectroscopy measurements indicated that surfactants BHA and NaOL co-absorbed on the smithsonite surface and only NaOL was present on the dolomite surface in the presence of BHOA.

Selective flotation of smithsonite, quartz and calcite using alkyl diamine ether as collector

The flotation separation of smithsonite from calcite and quartz using a alkyl diamine ether(GE-609)as the collector was investigated through micro-flotation experiments and the real ore flotation experiments.The results show that GE-609exhibits good collecting capability to three minerals without selectivity.The presence of sodium sulfide enhances the flotation of smithsonite and calcite while inhibits quartz.Moreover,both sodium silicate and sodium hexametaphosphate exhibit good selective inhibition to calcite.The real ore test results show that a zinc concentrate containing23.51%Zn with the recovery of71.02%is obtained in the closed-circuit test.To understand the adsorption of GE-609on smithsonite surface,zeta potential measurement and FTIR analysis were carried out,and the results indicate that the collector GE-609can adsorb on smithsonite surface through both electrostatic adsorption and chemical adsorption,and the presence of sodium sulfide enhances the adsorption of GE-609.

Studies of benzyl hydroxamic acid/calcium lignosulphonate addition order in the flotation separation of smithsonite from calcite

Flotation separation of smithsonite from calcite is difficult due to their similar surface properties.In the present study,a reagent scheme of depressant calcium lignosulphonate(CLS) and collector benzyl hydroxamic acid(BHA) was introduced in the flotation of smithsonite from calcite.Microflotation tests revealed that the efficient flotation of smithsonite from calcite could only be obtained with the addition order of BHA before CLS,which was opposite to the widely-used order that adding depressant prior to the collector.The zeta potential measurements indicated that BHA selectively adsorbed onto smithsonite surface,then not allowed the CLS adsorption onto the smithsonite surface rather than calcite surface because of the steric hindrance,thereby the smithsonite surface remained hydrophobic while calcite surface became more hydrophilic after the addition of CLS.As a result,the calcite flotation was completely depressed while the smithsonite flotation recovery was still in high value,leading to the optimal flotation separation performance.

Hydration mechanisms of smithsonite from DFT-D calculations and MD simulations

Investigation on the mineralwater interactions is crucial for understanding the subsequent interfacial reactions.Currently,the hydration mechanisms of smithsonite are still obscure.In this paper,the adsorption of H_(2)O at different coverage rates on smithsonite(101)surface was innovatively investigated using density-functional theory(DFT)calculations and molecular dynamics(MD)simulations by analyzing adsorption model,interaction energy,atomic distance,density of state,electron density difference,concentration profile,radial distribution function and self-diffusion coefficient.We found that single H_(2)O preferred to be dissociated on smithsonite(101)surface via the interaction of surface Zn with the Ow of H_(2)O and H-bond between Hw of H_(2)O and surface Os.However,dissociation adsorption and molecular adsorption coexisted on the smithsonite surface at a high coverage rate of H_(2)O,and dissociation adsorption remained the main adsorption mechanism.Moreover,we found the interaction between smithsonite surface and H_(2)O was weakened as a function of H_(2)O coverage,which was because the presence of interlayer H_(2)O and different layers of H_(2)O decreased the reactivity of the smithsonite surface.The H_(2)O is mainly adsorbed on the smithsonite surface by forming three layers of H_(2)O(about 10–15Å),with the ordering degree gradually decreasing.

A review of major non-sulfide zinc deposits in Iran

The numerous non-sulfide zinc ore deposits were the historical basis for the development of zinc mining in Iran.They include the Mehdiabad,Irankouh and Angouran world-class deposits,as well as the Zarigan and Haft-har deposits.These deposits were formed by supergene oxidation of primary sulfide minerals during the complex interplay of tectonic uplift,karst development,changes in the level of the water table,and weathering.Zn(Pb)carbonates,Zn-hydrosilicates and associated hydrated phases directly replace the primary ore bodies or fill cavities along fractures related to uplift tectonics.Direct replacement of primary sulfides is accompanied by distal precipitation of zinc non-sulfide minerals in cavities or internal sediments filling.The mineralogy of the non-sulfide mineralization in all six deposits is generally complex and consists of smithsonite,hydrozincite,and hemimorphite as the main economic minerals,accompanied by iron and manganese oxy-hydroxides and residual clays.Commonly,non-sulfide minerals in these deposits consist of two types of ore:red zinc ore(RZO),rich in Zn,Fe,Pb-(As)and white zinc ore(WZO),typically with very high zinc grades but low concentrations of iron and lead.Typical minerals of the RZO are Fe-oxyhydroxides,goethite,hematite,hemimorphite,smithsonite and/or hydrozincite and cerussite.Common minerals of the WZO are smithsonite or hydrozincite and only minor amounts of Fe-oxyhydroxides and hemimorphite.

Ligand selection for complex-leaching valuable metals in hydrometallurgy

A two-stage ligand selection method composed of a primary selection and a critical selection,for complex-leaching valuable metals was presented.At the primary selection stage,three conditions were discussed under a supposed ideal state by mathematical derivation.Generally,ligands selected under condition Ⅰwere easier for complex-leaching valuable metals than that under conditionⅡ,however,under conditionⅢ,ligands selected were hard to complex-leaching the valuable metals.Ligands that were out of these three conditions could be disposed directly.In critical selection,ligands selected in primary selection can be finalized.Case applications were provided for verifying the method.The application indicated that iminodiacetate(Ida2-)can be used as a complex agent for complex-leaching smithsonite(ZnCO3);the leaching condition should be controlled with pH 8-11;the relative error of the minimum consumption of Ida2-between the predicted and the calculated results is 5.3%.The results indicate that the theoretical derivations in the ideal state are reliable,and the method for ligand selection is practical and operable.