ZnO thin films with varying Ta concentrations were fabricated through magnetron sputtering.The crystallinity and surface morphology of the ZnO films are significantly influenced by the incorporation of Ta,as evidenced...ZnO thin films with varying Ta concentrations were fabricated through magnetron sputtering.The crystallinity and surface morphology of the ZnO films are significantly influenced by the incorporation of Ta,as evidenced by the X-ray diffraction and scanning electron microscopy results.The lattice constants,as determined by X-ray diffraction,contradict the disparity in Ta and Zn ion radii,which is attributed to the impact of interstitial defects.This inconsistency introduces variations in carrier concentration in this experiment compared with prior studies.Subsequent exploration of the luminescent characteristics and emission mechanism of defect levels in Ta-doped ZnO films was conducted through photoluminescence.Furthermore,the factors influencing the bandgap are discussed.展开更多
The recovery of zinc from low-grade zinc oxide ores with solvent extraction-electrowinning technique was investigated by using D2EHPA as extractant and 260 # kerosene as diluent. The results show that it is possible t...The recovery of zinc from low-grade zinc oxide ores with solvent extraction-electrowinning technique was investigated by using D2EHPA as extractant and 260 # kerosene as diluent. The results show that it is possible to selectively leach zinc from the ores by heap leaching. The zinc concentration of leach solution in the first leaching cycle is 32.57 g/L, and in the sixteenth cycle the zinc concentration is 8.27g/L after solvent extraction. The leaching solution is subjected to solvent extraction, scrubbing and selective stripping for enrichment of zinc and removal of impurities. The pregnant zinc sulfate solution produced from the stripping cycle is suitable for zinc electrowinning. Extra-pure zinc metal was obtained in the electrowinning test under conventional conditions.展开更多
The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc...The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc oxide ore 6:1,roasting temperature 450°C,holding time 150 min.The molar ratio of NaOH to zinc oxide ore was the most predominant factor affecting the extraction ratios of zinc oxide and silica.The mineral phase transformations were investigated by testing the phases of specimens obtained at different temperatures.The process was that silica reacted with molten NaOH to form Na_2SiO_3 at first,then transformed into Na_4SiO_4 with temperature rising.ZnCO_3 and its decomposing product ZnO reacted with NaOH to form Na_2ZnO_2.Na_2ZnSiO_4was also obtained.The reaction rate was investigated using unreacted shrinking core model.Two models used were chemical reaction at the particle surface and diffusion through the product layer.The results indicated that the reaction rate was combine-controlled by two models.The activation energy and frequency factor were obtained as 24.12 k J/mol and 0.0682,respectively.展开更多
In this article,the effect of using water/zinc oxide nanofluid as a working fluid on the performance of solar collector is investigated experimentally.The volumetric concentration of nanoparticles is 0.4%,and the part...In this article,the effect of using water/zinc oxide nanofluid as a working fluid on the performance of solar collector is investigated experimentally.The volumetric concentration of nanoparticles is 0.4%,and the particle size is 40 nm,and the mass flow rate of the fluid varies from 1 to 3 kg/min.For this experiment,a device has been prepared with appropriate measuring instruments whose energy source is solar radiation.The solar energy absorbed by the flat plate collector is absorbed by the nanofluid of water/zinc oxide.The nanofluid is pumped to the consumer,a heat exchanger,where it heats the water.The temperature,radiation level,flow rate,and pressure in different parts of the device were measured.The pressure drop and the heat transferred are the most important results of this experimental work.The ASHRAE standard is used to calculate efficiency.The results showed that the use of water/zinc oxide nanofluid increases the collector performance compared to water.For 1 kg/min of mass flow rate,the nanofluids have a 16% increase in efficiency compared to water.From the results,it can be concluded that the choice of optimum mass flow rate in both water and nanofluid cases increases efficiency.展开更多
Zinc extraction from crude zinc oxide(CZO)is beneficial to the full utilization of secondary resources and environmental protection.In this paper,a systematic investigation was carried out to study the leaching behavi...Zinc extraction from crude zinc oxide(CZO)is beneficial to the full utilization of secondary resources and environmental protection.In this paper,a systematic investigation was carried out to study the leaching behavior of CZO by using ammonia-ammonium carbonate solution.It was found that the maximum leaching rate of zinc from CZO dust was 95.7%under the conditions of[Zn]T:[NH 3]T:[CO_(3)^(2−)]=1:7.00:1.75,liquid to solid ratio 5:1,leaching temperature 30℃ and leaching time 60 min.Compared with pure zinc oxide(PZO)leaching,the CZO leaching required longer time and more leaching agents,which is caused by the Cd^(2+),Pb^(2+) and other metal cationic impurities in CZO.The metal cationic impurities dissolved in the leaching solution and combined with ammonium to form complexes,consuming leaching agents and affecting zinc leaching.展开更多
The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching effic...The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined. The leaching kinetics of low-grade zinc oxide ore in NH3-NH4Cl-H2O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057 kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69 μm, holding at 80 ℃ for 60 min, sum ammonia concentration of 7.5 mol/L, the molar ratio of ammonium to ammonia being 2-1, and the ratio (g/mL) of solid to liquid being 1-10.展开更多
A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine...A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 ℃ for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular a-Fe2O3 crystal structure. The length-to-diameter ratio ofa-Fe2O3 powder is （3-4）：1 with an average particle size of 0.5 μm.展开更多
Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxi...Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxide content exceeding the minimum industrial grade and iron ore, total iron content reaches a minimum industrial grade and associated with gold and silver; The mineralogical analysis result shows that lead and zinc mineral composition and configuration are very complexity. The zinc minerals and zinciferous minerals are sphalerite, hemimorphite, Smithsonite, Hydrozincite, zinc chlorite, limonite, zinc dolomite and zincocalcite; lead minerals and plumbiferous minerals are mainly galena, cerussite, anglesite, limonite and Coronadite; The minerals disseminated grain size are very fine and mineral dissemination characteristics are very complex ; expected theoretical recoveries for lead and zinc were 72% and 67% respectively. The results of this study provide basic data and theoretical basis for ore dressing.展开更多
Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimat...Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimate the transportations of these minerals. Fourteen soil samples and fifteen plant samples were collected from sites located in the basin and also in neighboring area and chemically analyzed.In展开更多
Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide particle.But indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assis...Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide particle.But indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst.In this work,Gallium oxide(β-Ga_2O_3)nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700-1000℃ using the iron,nickel,copper,cobalt and zinc oxide as a catalyst,respectively.The β-Ga_2O_3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850,900 and 950℃ in all the catalysts.But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst.As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods,and its diameter increased.From these results,we could be proposed that the growth mechanism of β-Ga_2O_3 nanowires was changed with synthesis temperature of nanowires.Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM,FE-SEM,EDX and XRD.展开更多
基金supported by the National Natural Science Foundation of China(61774140).
文摘ZnO thin films with varying Ta concentrations were fabricated through magnetron sputtering.The crystallinity and surface morphology of the ZnO films are significantly influenced by the incorporation of Ta,as evidenced by the X-ray diffraction and scanning electron microscopy results.The lattice constants,as determined by X-ray diffraction,contradict the disparity in Ta and Zn ion radii,which is attributed to the impact of interstitial defects.This inconsistency introduces variations in carrier concentration in this experiment compared with prior studies.Subsequent exploration of the luminescent characteristics and emission mechanism of defect levels in Ta-doped ZnO films was conducted through photoluminescence.Furthermore,the factors influencing the bandgap are discussed.
文摘The recovery of zinc from low-grade zinc oxide ores with solvent extraction-electrowinning technique was investigated by using D2EHPA as extractant and 260 # kerosene as diluent. The results show that it is possible to selectively leach zinc from the ores by heap leaching. The zinc concentration of leach solution in the first leaching cycle is 32.57 g/L, and in the sixteenth cycle the zinc concentration is 8.27g/L after solvent extraction. The leaching solution is subjected to solvent extraction, scrubbing and selective stripping for enrichment of zinc and removal of impurities. The pregnant zinc sulfate solution produced from the stripping cycle is suitable for zinc electrowinning. Extra-pure zinc metal was obtained in the electrowinning test under conventional conditions.
基金Projects(51774070,51204054)supported by the National Natural Science Foundation of ChinaProject(N150204009)supported by the Ministry of Education Basic Scientific Research Business Expenses,ChinaProject(2007CB613603)supported by the National Basic Research Program of China
文摘The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc oxide ore 6:1,roasting temperature 450°C,holding time 150 min.The molar ratio of NaOH to zinc oxide ore was the most predominant factor affecting the extraction ratios of zinc oxide and silica.The mineral phase transformations were investigated by testing the phases of specimens obtained at different temperatures.The process was that silica reacted with molten NaOH to form Na_2SiO_3 at first,then transformed into Na_4SiO_4 with temperature rising.ZnCO_3 and its decomposing product ZnO reacted with NaOH to form Na_2ZnO_2.Na_2ZnSiO_4was also obtained.The reaction rate was investigated using unreacted shrinking core model.Two models used were chemical reaction at the particle surface and diffusion through the product layer.The results indicated that the reaction rate was combine-controlled by two models.The activation energy and frequency factor were obtained as 24.12 k J/mol and 0.0682,respectively.
文摘In this article,the effect of using water/zinc oxide nanofluid as a working fluid on the performance of solar collector is investigated experimentally.The volumetric concentration of nanoparticles is 0.4%,and the particle size is 40 nm,and the mass flow rate of the fluid varies from 1 to 3 kg/min.For this experiment,a device has been prepared with appropriate measuring instruments whose energy source is solar radiation.The solar energy absorbed by the flat plate collector is absorbed by the nanofluid of water/zinc oxide.The nanofluid is pumped to the consumer,a heat exchanger,where it heats the water.The temperature,radiation level,flow rate,and pressure in different parts of the device were measured.The pressure drop and the heat transferred are the most important results of this experimental work.The ASHRAE standard is used to calculate efficiency.The results showed that the use of water/zinc oxide nanofluid increases the collector performance compared to water.For 1 kg/min of mass flow rate,the nanofluids have a 16% increase in efficiency compared to water.From the results,it can be concluded that the choice of optimum mass flow rate in both water and nanofluid cases increases efficiency.
基金Project(2020YFC1909805)supported by the National Key Research and Development Program of ChinaProjects(51504293,51574284)supported by the National Natural Science Foundation of China+2 种基金Project(2018-GX-A7)supported by Qinghai Provincial Major Scientific and Technological Special Project of ChinaProject(2020SK2125)supported by the Key Research and Development Program of Hunan Province,ChinaProject(CSUZC202129)supported by Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University,China。
文摘Zinc extraction from crude zinc oxide(CZO)is beneficial to the full utilization of secondary resources and environmental protection.In this paper,a systematic investigation was carried out to study the leaching behavior of CZO by using ammonia-ammonium carbonate solution.It was found that the maximum leaching rate of zinc from CZO dust was 95.7%under the conditions of[Zn]T:[NH 3]T:[CO_(3)^(2−)]=1:7.00:1.75,liquid to solid ratio 5:1,leaching temperature 30℃ and leaching time 60 min.Compared with pure zinc oxide(PZO)leaching,the CZO leaching required longer time and more leaching agents,which is caused by the Cd^(2+),Pb^(2+) and other metal cationic impurities in CZO.The metal cationic impurities dissolved in the leaching solution and combined with ammonium to form complexes,consuming leaching agents and affecting zinc leaching.
基金Project(2007CB613604) supported by the Major State Basic Research Development Program of ChinaProject(50674104) supported by the National Natural Science Foundation of ChinaProject(GJJ08279) supported by the Department of Education of Jiangxi Province
文摘The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined. The leaching kinetics of low-grade zinc oxide ore in NH3-NH4Cl-H2O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057 kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69 μm, holding at 80 ℃ for 60 min, sum ammonia concentration of 7.5 mol/L, the molar ratio of ammonium to ammonia being 2-1, and the ratio (g/mL) of solid to liquid being 1-10.
基金Project(50674104) supported by the National Natural Science Foundation of ChinaProject(2006BA02B04-4-2) supported by the Planned Science and Technology of China
文摘A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 ℃ for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular a-Fe2O3 crystal structure. The length-to-diameter ratio ofa-Fe2O3 powder is （3-4）：1 with an average particle size of 0.5 μm.
文摘Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxide content exceeding the minimum industrial grade and iron ore, total iron content reaches a minimum industrial grade and associated with gold and silver; The mineralogical analysis result shows that lead and zinc mineral composition and configuration are very complexity. The zinc minerals and zinciferous minerals are sphalerite, hemimorphite, Smithsonite, Hydrozincite, zinc chlorite, limonite, zinc dolomite and zincocalcite; lead minerals and plumbiferous minerals are mainly galena, cerussite, anglesite, limonite and Coronadite; The minerals disseminated grain size are very fine and mineral dissemination characteristics are very complex ; expected theoretical recoveries for lead and zinc were 72% and 67% respectively. The results of this study provide basic data and theoretical basis for ore dressing.
文摘Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimate the transportations of these minerals. Fourteen soil samples and fifteen plant samples were collected from sites located in the basin and also in neighboring area and chemically analyzed.In
文摘Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide particle.But indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst.In this work,Gallium oxide(β-Ga_2O_3)nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700-1000℃ using the iron,nickel,copper,cobalt and zinc oxide as a catalyst,respectively.The β-Ga_2O_3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850,900 and 950℃ in all the catalysts.But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst.As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods,and its diameter increased.From these results,we could be proposed that the growth mechanism of β-Ga_2O_3 nanowires was changed with synthesis temperature of nanowires.Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM,FE-SEM,EDX and XRD.
