Hemimorphite exhibits poor floatability during sulfidization flotation.Cu^(2+)and Pb^(2+)addition enhances the reactivity of the hemimorphite surface and subsequently improves its flotation behavior.In this study,the ...Hemimorphite exhibits poor floatability during sulfidization flotation.Cu^(2+)and Pb^(2+)addition enhances the reactivity of the hemimorphite surface and subsequently improves its flotation behavior.In this study,the mechanisms of Cu^(2+)Pb^(2+)adsorption onto a hemimorphite surface were investigated.We examined the interaction mechanism of xanthate with the hemimorphite surface and observed the changes in the mineral surface hydrophobicity after the synergistic activation with Cu^(2+)Pb^(2+).Microflotation tests indicated that individual activation with Cu or Pb^(2+)increased the flotation recovery of hemimorphite,with Pb^(2+)showing greater effectiveness than Cu^(2+).Meanwhile,synergistic activation with Cu^(2+)Pb^(2+)considerably boosted the flotation recovery of hemimorphite.Cu^(2+)and Pb^(2+)were both adsorbed onto the hemimorphite surface,forming an adsorption layer containing Cu or Pb.Following the synergistic activation with Cu^(2+)+Pb^(2+),the activated layer on the hemimorphite surface consisted of Cu and Pb and a larger amount of the active product compared with the surface activated by Cu^(2+)or Pb^(2+)alone.In addition,xanthate adsorption on the hemimorphite surface increased noticeably after synergistic activation with Cu^(2+)Pb^(2+),suggesting a vigorous reaction between xanthate and the activated minerals.Therefore,synergistic activation with Cu^(2+)Pb^(2+)effectively increased the content of active products on the hemimorphite surface,thereby enhancing mineral surface reactivity,promoting collector adsorption,and improving surface hydrophobicity.展开更多
The low reactivity of hemimorphite surfaces hinders the effective action of sulfidizing agents and xanthate,resulting in unsatisfactory flotation performance.To enhance the surface reactivity of hemi-morphite with sul...The low reactivity of hemimorphite surfaces hinders the effective action of sulfidizing agents and xanthate,resulting in unsatisfactory flotation performance.To enhance the surface reactivity of hemi-morphite with sulfidizing agents and xanthate,Cu/Pb binary metal ions were introduced into the sul-fidization flotation system to enhance the sulfidization process and thereby promote hemimorphite flotation.The flotation results demonstrated a remarkable improvement in the hemimorphite flotation recovery when Cu/Pb binary metal ions were added prior to sulfidization.The flotation recovery of hemi-morphite increased from less than 5%to over 80%.After strengthening the sulfidization of hemimorphite with Cu/Pb binary metal ions,the mineral surface formed multicomponent sulfide products composed of zinc,copper,and lead sulfide.The reactivity of the copper-lead sulfide components exceeds that of the zinc sulfide component;thus,the enhancement by Cu/Pb binary metal ions not only increases the content of sulfide products on the hemimorphite surface but also augments their reactivity.Contact angle and adsorption experiments indicated that after enhanced sulfidization with Cu/Pb binary metal ions,the hemimorphite surface adsorbed a greater amount of xanthate,significantly increasing the mineral sur-face hydrophobicity.Consequently,the enhanced sulfidization by Cu/Pb binary metal ions effectively improved the flotation behavior of hemimorphite,presenting an innovative sulfidization system for the flotation recovery of zinc silicate minerals in zinc oxide ores.展开更多
Zn reduction was investigated by the vacuum carbothermic reduction of hemimorphite with or without CaF2 as catalyst.Results indicate that CaF2 can catalyze the carbothermic reduction of zinc silicate,decrease the reac...Zn reduction was investigated by the vacuum carbothermic reduction of hemimorphite with or without CaF2 as catalyst.Results indicate that CaF2 can catalyze the carbothermic reduction of zinc silicate,decrease the reaction temperature and time.The lower the reaction temperature and the more the amount of CaF2,the better the catalytic effect.The optimal process condition is obtained as follows：the addition of about 10% CaF2,the reaction temperature of 1373 K,the molar ratio of C to ZnTotal of 2.5,the pressure of system lower than 20 kPa,the reaction time of about 40 min.Under the optimal process condition,the zinc reduction rate is about 93% from hemimorphite.展开更多
The solubility of natural hemimorphite in ammonium sulfate solution was measured by isothermal solution method at 25 °C and the dissolved residue of hemimorphite was investigated by X-ray powder diffraction （XRD...The solubility of natural hemimorphite in ammonium sulfate solution was measured by isothermal solution method at 25 °C and the dissolved residue of hemimorphite was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM） and Fourier transform infrared spectroscopy （FTIR） methods. The results show that zinc and silica in hemimorphite simultaneously dissolve in ammonium sulfate solution. The solubility of zinc in solution increases rapidly from 4.5381 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 11.5083 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The solubility of silica in solution increases slowly from 2.5509 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 7.2891 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The dissolved residue is the characteristic of hemimorphite Zn4Si2O7（OH）2·H2O based on the results of the XRD, SEM and FTIR. Thus, no phase transition occurs in the dissolution process of hemimorphite in ammonium sulfate solution.展开更多
The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation...The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation results indicated that hemimorphite floats when the S(Ⅱ)–Pb(Ⅱ)–xanthate process is used; a maximum recovery of approximately 90% was obtained.Zeta-potential,contact-angle,scanning electron microscopy–energy-dispersive spectrometry(SEM–EDS),and diffuse-reflectance infrared Fourier transform spectroscopy(DRIFTS) measurements were used to characterize the activation products on the hemimorphite surface and their subsequent interaction with sodium butyl xanthate(SBX).The results showed that a Zn S coating formed on the hemimorphite surface after the sample was conditioned in an Na2 S solution.However,the formation of a Zn S coating on the hemimorphite surface did not improve hemimorphite flotation.With the subsequent addition of lead cations,Pb S species formed on the mineral surface.The formation of the Pb S species on the surface of hemimorphite significantly increased the adsorption capacity of SBX,forming lead xanthate(referred to as chemical adsorption) and leading to a substantial improvement in hemimorphite flotation.Our results indicate that the addition of lead cations is a critical step in the successful flotation of hemimorphite using the sulfidization–lead ion activation–xanthate process.展开更多
In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium su...In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.展开更多
The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy ...The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） analysis. The results show that hemimorphite is soluble in NH3-（NH4）2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-（NH4）2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr（NH3） （total ammonia concentration） at different NH3/NH4^＋ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct（NH3）-4.1245 mol/kg NH3-（NH4）2SO4-H2O solution to 0.0046 mol/kg in cT（NH3）=7.6035 mol/kg NH3-（NH4）2SO4-H2O solution.展开更多
Effectively strengthening the surface sulfidation is essential for recovering hemimorphite by froth flotation.In this work,inductively coupled plasma optical emission spectrometer(ICP-OES)measurements,Visual MINTEQ ca...Effectively strengthening the surface sulfidation is essential for recovering hemimorphite by froth flotation.In this work,inductively coupled plasma optical emission spectrometer(ICP-OES)measurements,Visual MINTEQ calculation,X-ray photoelectron spectroscopy(XPS)analysis,time of flight secondary ion mass spectrometry(ToF-SIMS)analysis,and micro-flotation experiments were explored to systematically investigate the effect of ammonium sulfate((NH_(4))_(2)SO_(4))on the formation of zinc sulfide species on hemimorphite surface and its role in sulfidation flotation.The results showed that(NH_(4))_(2)SO_(4)exhibited a positive influence on hemimorphite sulfidation flotation.It was ascribed to the number of zinc components in the form of Zn^(2+)and[Zn(NH_(3))_(i)]^(2+)(i=1–4)increased in the flotation system after hemimorphite treatment with(NH_(4))_(2)SO_(4),which was beneficial to its interaction with sulfur species in solution,resulting in a dense and stable zinc sulfide layer generated on the hemimorphite surface.[Zn(NH_(3))_(i)]^(2+)participated in the sulfidation reaction of hemimorphite as a transition state.In addition the sulfidation reaction of hemimorphite was accelerated by(NH_(4))_(2)SO_(4).Thus,(NH_(4))_(2)SO_(4)presents a vital role in promoting the sulfidation of hemimorphite.展开更多
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...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.展开更多
Oxidized lead and zinc resources have been underutilized for a long time.With the rapid depletion of the lead-zinc sulfide ores,there is an urgent need to increase the efficient utilization of lead-zinc oxide ores.Flo...Oxidized lead and zinc resources have been underutilized for a long time.With the rapid depletion of the lead-zinc sulfide ores,there is an urgent need to increase the efficient utilization of lead-zinc oxide ores.Flotation is a versatile method for the pre-enrichment of lead-zinc oxide ores.Due to the strong hydration of lead-zinc oxide minerals and the easy dissolution of metal ions on the surface,the flotation separation of lead-zinc oxide ores remains a major challenge to date.Therefore,sulfidation reconstruction of oxidized lead-zinc minerals prior to flotation is crucial for altering their surface properties.This paper reviews the progress of sulfidation pretreatment technology for typical lead-zinc oxide minerals,including cerussite,smithsonite,and hemimorphite.Currently,the utilization of sulfurizing agents for surface sulfidation pretreatment of lead-zinc oxide minerals,followed by flotation recovery using amine collectors,represents the most widely employed process.Constrained by factors such as low sulfidation rates and the propensity for sulfidation products to desorb,flotation recovery of lead-zinc oxide ores remains low.At present,reinforced mineral surface sulfidation by the addition of ammonium salts is a common method to increase the sulfidation rate of lead-zinc oxide ores.In particular,this paper summarizes the mechanisms of different sulfidation reconstruction technologies and analyses the main factors affecting surface sulfidation,as well as outlines the prospects for future research.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52304291 and 52264026)Yunnan Fundamental Research Projects,China(No.202301AW070018)。
文摘Hemimorphite exhibits poor floatability during sulfidization flotation.Cu^(2+)and Pb^(2+)addition enhances the reactivity of the hemimorphite surface and subsequently improves its flotation behavior.In this study,the mechanisms of Cu^(2+)Pb^(2+)adsorption onto a hemimorphite surface were investigated.We examined the interaction mechanism of xanthate with the hemimorphite surface and observed the changes in the mineral surface hydrophobicity after the synergistic activation with Cu^(2+)Pb^(2+).Microflotation tests indicated that individual activation with Cu or Pb^(2+)increased the flotation recovery of hemimorphite,with Pb^(2+)showing greater effectiveness than Cu^(2+).Meanwhile,synergistic activation with Cu^(2+)Pb^(2+)considerably boosted the flotation recovery of hemimorphite.Cu^(2+)and Pb^(2+)were both adsorbed onto the hemimorphite surface,forming an adsorption layer containing Cu or Pb.Following the synergistic activation with Cu^(2+)+Pb^(2+),the activated layer on the hemimorphite surface consisted of Cu and Pb and a larger amount of the active product compared with the surface activated by Cu^(2+)or Pb^(2+)alone.In addition,xanthate adsorption on the hemimorphite surface increased noticeably after synergistic activation with Cu^(2+)Pb^(2+),suggesting a vigorous reaction between xanthate and the activated minerals.Therefore,synergistic activation with Cu^(2+)Pb^(2+)effectively increased the content of active products on the hemimorphite surface,thereby enhancing mineral surface reactivity,promoting collector adsorption,and improving surface hydrophobicity.
基金supported by National Natural Science Foundation of China(Nos.52304291 and 52264026)Yunnan Fundamental Research Projects(No.202301AW070018).
文摘The low reactivity of hemimorphite surfaces hinders the effective action of sulfidizing agents and xanthate,resulting in unsatisfactory flotation performance.To enhance the surface reactivity of hemi-morphite with sulfidizing agents and xanthate,Cu/Pb binary metal ions were introduced into the sul-fidization flotation system to enhance the sulfidization process and thereby promote hemimorphite flotation.The flotation results demonstrated a remarkable improvement in the hemimorphite flotation recovery when Cu/Pb binary metal ions were added prior to sulfidization.The flotation recovery of hemi-morphite increased from less than 5%to over 80%.After strengthening the sulfidization of hemimorphite with Cu/Pb binary metal ions,the mineral surface formed multicomponent sulfide products composed of zinc,copper,and lead sulfide.The reactivity of the copper-lead sulfide components exceeds that of the zinc sulfide component;thus,the enhancement by Cu/Pb binary metal ions not only increases the content of sulfide products on the hemimorphite surface but also augments their reactivity.Contact angle and adsorption experiments indicated that after enhanced sulfidization with Cu/Pb binary metal ions,the hemimorphite surface adsorbed a greater amount of xanthate,significantly increasing the mineral sur-face hydrophobicity.Consequently,the enhanced sulfidization by Cu/Pb binary metal ions effectively improved the flotation behavior of hemimorphite,presenting an innovative sulfidization system for the flotation recovery of zinc silicate minerals in zinc oxide ores.
基金Project(2007CB613601) supported by the National Basic Research Program of ChinaProject(51142001) supported the National Natural Science Foundation of China+1 种基金Project(11B099) supported the Scientific Research Fund of the Human Provincial Education Department, ChinaProject(2011TT2038) supported the Scientific Research Fund of the Human Provincial Scientific and Technological Department, China
文摘Zn reduction was investigated by the vacuum carbothermic reduction of hemimorphite with or without CaF2 as catalyst.Results indicate that CaF2 can catalyze the carbothermic reduction of zinc silicate,decrease the reaction temperature and time.The lower the reaction temperature and the more the amount of CaF2,the better the catalytic effect.The optimal process condition is obtained as follows：the addition of about 10% CaF2,the reaction temperature of 1373 K,the molar ratio of C to ZnTotal of 2.5,the pressure of system lower than 20 kPa,the reaction time of about 40 min.Under the optimal process condition,the zinc reduction rate is about 93% from hemimorphite.
基金Foundation item:Project(2007CB613601)supported by the National Basic Research and Development Program of ChinaProject(511340071)supported by the National Natural Science Foundation of China
文摘The solubility of natural hemimorphite in ammonium sulfate solution was measured by isothermal solution method at 25 °C and the dissolved residue of hemimorphite was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM） and Fourier transform infrared spectroscopy （FTIR） methods. The results show that zinc and silica in hemimorphite simultaneously dissolve in ammonium sulfate solution. The solubility of zinc in solution increases rapidly from 4.5381 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 11.5083 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The solubility of silica in solution increases slowly from 2.5509 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 7.2891 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The dissolved residue is the characteristic of hemimorphite Zn4Si2O7（OH）2·H2O based on the results of the XRD, SEM and FTIR. Thus, no phase transition occurs in the dissolution process of hemimorphite in ammonium sulfate solution.
基金financially supported by the State Key Development Program for Basic Research of China (No.2014CB643402)the Collaborative Innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources of Central South University
文摘The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation results indicated that hemimorphite floats when the S(Ⅱ)–Pb(Ⅱ)–xanthate process is used; a maximum recovery of approximately 90% was obtained.Zeta-potential,contact-angle,scanning electron microscopy–energy-dispersive spectrometry(SEM–EDS),and diffuse-reflectance infrared Fourier transform spectroscopy(DRIFTS) measurements were used to characterize the activation products on the hemimorphite surface and their subsequent interaction with sodium butyl xanthate(SBX).The results showed that a Zn S coating formed on the hemimorphite surface after the sample was conditioned in an Na2 S solution.However,the formation of a Zn S coating on the hemimorphite surface did not improve hemimorphite flotation.With the subsequent addition of lead cations,Pb S species formed on the mineral surface.The formation of the Pb S species on the surface of hemimorphite significantly increased the adsorption capacity of SBX,forming lead xanthate(referred to as chemical adsorption) and leading to a substantial improvement in hemimorphite flotation.Our results indicate that the addition of lead cations is a critical step in the successful flotation of hemimorphite using the sulfidization–lead ion activation–xanthate process.
基金the Fundamental Research Funds for the Central Universities(Nos.2022JCCXHH09 and 2022YJSHH01)the Yueqi Outstanding Scholar award of CUMTB+3 种基金the National Key R&D Program of China(No.SQ2022YFC2900065)the Ordos Science&Technology Plan(No.202204)the National Natural Science Foundation of China(No.52274283)the Open Research Fund of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2107)。
文摘In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.
基金Projects(511340071) supported by the National Natural Science Foundation of China
文摘The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） analysis. The results show that hemimorphite is soluble in NH3-（NH4）2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-（NH4）2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr（NH3） （total ammonia concentration） at different NH3/NH4^＋ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct（NH3）-4.1245 mol/kg NH3-（NH4）2SO4-H2O solution to 0.0046 mol/kg in cT（NH3）=7.6035 mol/kg NH3-（NH4）2SO4-H2O solution.
基金Fundamental Research Funds for the Central Universities(No.2023YQTD03,2022JCCX HH09,2022YJSHH01)the Yueqi Outstanding Scholaraward of China University of Mining&Technology(Beijing)+3 种基金the National Natural Science Foundation of China(No.52274283)the National Key R&D Program of China(No.SQ2022YFC2900065)the Ordos Science&Technology Plan(No.202204&2023XM06)the Open Research Fund of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF 2107)。
文摘Effectively strengthening the surface sulfidation is essential for recovering hemimorphite by froth flotation.In this work,inductively coupled plasma optical emission spectrometer(ICP-OES)measurements,Visual MINTEQ calculation,X-ray photoelectron spectroscopy(XPS)analysis,time of flight secondary ion mass spectrometry(ToF-SIMS)analysis,and micro-flotation experiments were explored to systematically investigate the effect of ammonium sulfate((NH_(4))_(2)SO_(4))on the formation of zinc sulfide species on hemimorphite surface and its role in sulfidation flotation.The results showed that(NH_(4))_(2)SO_(4)exhibited a positive influence on hemimorphite sulfidation flotation.It was ascribed to the number of zinc components in the form of Zn^(2+)and[Zn(NH_(3))_(i)]^(2+)(i=1–4)increased in the flotation system after hemimorphite treatment with(NH_(4))_(2)SO_(4),which was beneficial to its interaction with sulfur species in solution,resulting in a dense and stable zinc sulfide layer generated on the hemimorphite surface.[Zn(NH_(3))_(i)]^(2+)participated in the sulfidation reaction of hemimorphite as a transition state.In addition the sulfidation reaction of hemimorphite was accelerated by(NH_(4))_(2)SO_(4).Thus,(NH_(4))_(2)SO_(4)presents a vital role in promoting the sulfidation of hemimorphite.
文摘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.
基金financially supported by the National Natural Science Foundation of China (No.52374260)。
文摘Oxidized lead and zinc resources have been underutilized for a long time.With the rapid depletion of the lead-zinc sulfide ores,there is an urgent need to increase the efficient utilization of lead-zinc oxide ores.Flotation is a versatile method for the pre-enrichment of lead-zinc oxide ores.Due to the strong hydration of lead-zinc oxide minerals and the easy dissolution of metal ions on the surface,the flotation separation of lead-zinc oxide ores remains a major challenge to date.Therefore,sulfidation reconstruction of oxidized lead-zinc minerals prior to flotation is crucial for altering their surface properties.This paper reviews the progress of sulfidation pretreatment technology for typical lead-zinc oxide minerals,including cerussite,smithsonite,and hemimorphite.Currently,the utilization of sulfurizing agents for surface sulfidation pretreatment of lead-zinc oxide minerals,followed by flotation recovery using amine collectors,represents the most widely employed process.Constrained by factors such as low sulfidation rates and the propensity for sulfidation products to desorb,flotation recovery of lead-zinc oxide ores remains low.At present,reinforced mineral surface sulfidation by the addition of ammonium salts is a common method to increase the sulfidation rate of lead-zinc oxide ores.In particular,this paper summarizes the mechanisms of different sulfidation reconstruction technologies and analyses the main factors affecting surface sulfidation,as well as outlines the prospects for future research.
