Ida2--H2O system（iminodiacetate aqueous solution） was used to leach a low grade zinc oxide ore for Zn extraction.The effects of leaching time,liquid-solid ratio（L/S）,total concentration of Ida2-（[Ida2-]T）,leachi...Ida2--H2O system（iminodiacetate aqueous solution） was used to leach a low grade zinc oxide ore for Zn extraction.The effects of leaching time,liquid-solid ratio（L/S）,total concentration of Ida2-（[Ida2-]T）,leaching temperature and pH on Zn leaching recovery and the dissolution of impurities such as Ca,Mg,Cu,Ni,Fe,Pb and Cd were investigated.Results show that Ca,Mg and Fe in ores were hardly dissolved in alkalescent iminodiacetate aqueous solution,while valuable metals such as Cu,Ni,Pb and Cd were partly dissolved into leaching liquor with Zn.The recovery of Zn reaches 76.6% when the ores were leached for 4 h at 70 ℃ by 0.9 mol/L iminodiacetate aqueous solution with pH of 8 and L/S of 5：1.展开更多
A novel process was proposed for the activation pretreatment of limonitic laterite ores by Na2CO3 roasting. Dechromization and dealumination kinetics of the laterite ores and the effect of particle size, Na2CO3-ore ma...A novel process was proposed for the activation pretreatment of limonitic laterite ores by Na2CO3 roasting. Dechromization and dealumination kinetics of the laterite ores and the effect of particle size, Na2CO3-ore mass ratio, and roasting temperature on Cr and Al extraction were studied. Experimental results indicate that the extraction rates of Cr and Al are up to 99%and 82%, respectively, under the optimal particle size of 44–74μm, Na2CO3-to-ore mass ratio of 0.6：1, and temperature of 1000 ℃. Dechromization within the range of 600–800 oC is controlled by the diffusion through the product layer with an apparent activation energy of 3.9 kJ/mol, and that it is controlled by the chemical reaction at the surface within the range of 900–1100 ℃ with an apparent activation energy of 54.3 kJ/mol. Besides, the Avrami diffusion controlled model with on apparent activation energy of 16.4 kJ/mol is most applicable for dealumination. Furthermore, 96.8%Ni and 95.6%Co could be extracted from the alkali-roasting residues in the subsequent pressure acid leaching process.展开更多
Coke oven gas(COG)and natural gas(NG),both high-calorific by-products derived from the steel industry,have gained prominence as alternative fuels in the sintering process,thereby supporting dual objectives of emission...Coke oven gas(COG)and natural gas(NG),both high-calorific by-products derived from the steel industry,have gained prominence as alternative fuels in the sintering process,thereby supporting dual objectives of emission reduction and carbon neutrality.While existing research on hydrogen-rich gas injection has predominantly concentrated on conventional thin-bed sintering,investigations into its application within thick-bed sintering remain comparatively scarce.Thick-bed sintering,recognized for enhancing energy efficiency and increasing sinter output,encounters challenges such as uneven heat distribution and diminished permeability,which can negatively impact process efficiency and product quality.To address these issues,sinter pot experiments were conducted to assess the effects of NG and COG injection on thick-bed sintering performance.Findings reveal that NG injection in thick beds mirrors the behavior observed in conventional thin-bed sintering,effectively optimizing the process and achieving a carbon reduction potential exceeding 10%.In contrast,COG injection in thick-bed conditions demonstrates notable differences,substantially lowering the solid fuel consumption rate but detrimentally affecting sinter strength and overall production.However,by optimizing the timing of COG injection,it is feasible to improve sinter yield while concurrently reducing solid fuel usage.These outcomes provide valuable insights for the advancement of gas injection technologies in thick-bed sintering,thereby contributing to energy conservation and emission mitigation efforts within the sintering industry.展开更多
An innovative technology,nitric acid pressure leaching of limonitic laterite ores,was proposed by our research team.The HNO3 regeneration is considerable significance for the improvement of the proposed technology and...An innovative technology,nitric acid pressure leaching of limonitic laterite ores,was proposed by our research team.The HNO3 regeneration is considerable significance for the improvement of the proposed technology and its commercial application,but it has not been systematically investigated.Herein,regenerating HNO3 from Ca(NO3)2 solution with low-cost H2SO4,and simultaneous synthesis of fibrous CaSO4·2H2O by-products were studied.As a theoretical basis,the solubility of CaSO4·2H2O in HNO3 medium is studied.It is concluded that the solubility of CaSO4·2H2O increases with increasing temperature or increasing HNO3 concentration,which has considerable guiding significance for the subsequent experimental research and analysis.Then,the effects of various factors on the residual Ca^2+ concentration of filtrate,the regenerated HNO3 concentration and the morphology of synthesized products are investigated using ICP-AES and SEM.And the effect mechanism is also analyzed.The results indicate the regenerated HNO3 concentration reaches 116 g/L with the residual Ca^2+ concentration being 9.7 g/L at the optimum conditions.Moreover,fibrous CaSO4·2H2O by-products with high aspect ratios(length,406.32μm;diameter,14.71μm;aspect ratio,27.62)can be simultaneously synthesized.展开更多
In the chemical looping with oxygen uncoupling(CLOU)process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combusti...In the chemical looping with oxygen uncoupling(CLOU)process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combustion rate of carbon is faster than the decoupling rate of oxygen carrier(OC).Hence,high temperature tolerance and rapid oxygen release rate of CuO modified by three different ores were investigated in this study.The kinetics analysis of oxygen decoupling with Cu-based oxygen carriers was also evaluated.Results showed that CuO modified by chrysolite had faster oxygen release rate than that of CuO.Limestone showed obvious positive effect on the oxidization process.The selected OCs could keep stable in at least 20 cycles,for about 1200 min.Shrinking core model(SCM)fitted well for the decoupling process in the temperature range of 1123-1223 K.Reduction rate kinetic information may aid in the development of chemical looping with oxygen uncoupling(CLOU)technologies during reactor design and process modeling.Ternary doped copper oxide with chrysolite and limestone could improve the reactivity of CuO in decoupling and coupling process and also improve the high temperature tolerance.展开更多
FeS_(2)is a promising anode material for potassium-ion batteries(PIBs),with the advantages of low cost and high capacity.However,it still faces challenges of capacity fading and poor rate performance in potassium stor...FeS_(2)is a promising anode material for potassium-ion batteries(PIBs),with the advantages of low cost and high capacity.However,it still faces challenges of capacity fading and poor rate performance in potassium storage.Rational structural design is one way to overcome these drawbacks.In this work,MIL-88B-Fe-derived FeS_(2)nanoparticles/N-doped carbon nanofibers(M-FeS_(2)@CNFs)with expansion buffer capability are designed and synthesized for high-performance PIB anodes via electrospinning and subsequent sulfurization.The uniformly distributed cavity-type porous structure effectively mitigates the severe aggregation problem of FeS_(2)nanoparticles during cycling and buffers the volume change,further enhancing the potassium storage capacity.Meanwhile,the robust KF-rich solid electrolyte interphase induced by methyl trifluoroethylene carbonate(FEMC)additive improves the cycling stability of the M-FeS_(2)@CNF anode.In the electrolyte with 3 wt%FEMC,the M-FeS_(2)@CNF anode shows a reversible specific capacity of 592.7 mA h g^(-1)at 0.1 A g^(-1),an excellent rate capability of 327.1 mA h g^(-1)at 5 A g^(-1),and a retention rate 80.7%over 1000 cycles at 1 A g^(-1).More importantly,when assembled with a K_(1.84)Ni[Fe(CN)_(6)]_(0.88)·0.49H_(2)O cathode,the full battery manifests excellent cycle stability and high rate performance.This study demonstrates the significant importance of the synergistic effect of structural regulation and electrolyte optimization in achieving high cycling stability of PIBs.展开更多
Iron disulfide(FeS_(2))has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau.However,low thermal decomposition temperature,poor conductivity and inferior actua...Iron disulfide(FeS_(2))has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau.However,low thermal decomposition temperature,poor conductivity and inferior actual specific capacity limit its wide applications.Herein,we report a gold-doped FeS_(2)(FeS_(2)-Au),which not only reduces the band gap of the FeS_(2)crystals but also enriches the electron transport path of FeS_(2)by the formation of Au nanoparticles.First-principles calculation shows that the diffusion energy barrier of lithium-ion is reduced after the Au-doped FeS_(2).In addition,Au increases the electron cloud density around sulfur atoms,which helps to enhance the stability of Fe-S covalent bonds and thus results in better thermal stability of FeS_(2).When the Au content is 130μg·g^(-1)(FeS_(2)-Au_(4)),the thermal decomposition temperature(TG5%)of FeS_(2)-Au is 72.2℃ higher than that of pristine FeS_(2).At a discharge temperature of 500℃,a current density of 200 mA·cm^(-2) and a cutoff voltage of 1.4 V,FeS_(2)-Au_(4)demonstrates superior specific capacity and high specific energy compared to FeS_(2).More precisely,the specific capacity of FeS_(2)-Au_(4)attains a value of 379 mAh·g^(-1),with a corresponding specific energy of 714 Wh·kg^(-1).In contrast,the discharge specific capacity and specific energy of FeS_(2)are lower,amounting to 348 mAh·g^(-1)and 656 Wh·kg^(-1),respectively.This study offers a novel approach to enhancing the electrochemical performance of FeS_(2)in high-temperature molten salt electrochemical systems(thermal batteries),thereby laying a solid foundation for its potential practical application.展开更多
Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^(-)/h^(+) pairs together with the production of heat energy.However,the inefficient separation of charge...Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^(-)/h^(+) pairs together with the production of heat energy.However,the inefficient separation of charge carriers and inadequate response to near-infrared(NIR)light usually leads to the unsatisfactory photocatalytic efficiency,hindering their application potentials.In this work,a significantly enhanced photothermal catalytic hydrogen evolution reaction over the lead-free perovskite Cs_(3)Bi_(2)Br_(9)/FeS_(2)(CBB/FS)heterostructure is simultaneously verified,where the CBB/FS Z-scheme heterojunctions display the strong stability and superb photothermal catalytic activity.Under the simulated solar irradiation(AM 1.5G),the optimized CBB/FS-5 achieves a photocatalytic hydrogen evolution rate of 31.5 mmol g^(-1)h^(-1),which is 112.6 and 77.1 times higher than that of FS and CBB,respectively,together with an apparent quantum yield of 29.5%at 420 nm.This significantly improved photocatalytic H_(2)evolution can be mainly attributed to the Z-scheme charge transfer and photothermal-assisted synergistically enhanced photocatalytic H_(2)production,and the potential mechanism of the enhanced photocatalytic H_(2)evolution is also proposed by photoelectrochemical characterizations,in situ XPS,EPR spectra,and the DFT calculations.This work provides new insights to the design of high-efficient photothermal catalysts,leading to the sustainable and efficient solutions towards the energy and environmental challenges.展开更多
Replacing solid carbon with hydrogen gas in ferromanganese production presents a forward-thinking,sustainable solution to re-ducing the ferro-alloy industry’s carbon emissions.The HAlMan process,a groundbreaking and ...Replacing solid carbon with hydrogen gas in ferromanganese production presents a forward-thinking,sustainable solution to re-ducing the ferro-alloy industry’s carbon emissions.The HAlMan process,a groundbreaking and eco-friendly method,has been meticu-lously researched and scaled up from laboratory experiments to pilot tests,aiming to drastically cut CO_(2) emissions associated with ferro-manganese production.This innovative process could potentially reduce CO_(2) emissions by about 1.5 tonnes for every tonne of ferroman-ganese produced.In this study,a lab-scale vertical thermogravimetric furnace was used to carry out the pre-reduction of Nchwaning man-ganese ore,where direct reduction occurred with H_(2) gas under controlled isothermal conditions at 700,800,and 900℃.The results indic-ated that higher pre-reduction temperatures(800 and 900℃)effectively converted Fe_(2)O_(3) to metallic iron and Mn_(2)O_(3) to MnO.By continu-ously monitoring the mass changes during the reduction,both the rate and extent of reduction were assessed.A second-order reaction model was applied to validate the experimental outcomes of H_(2) reduction at various temperatures,showing apparent activation energies of 29.79 kJ/mol for dried ore and 61.71 kJ/mol for pre-calcined ore.The reduction kinetics displayed a strong dependence on temperature,with higher temperatures leading to quicker and more complete reductions.The kinetics analysis suggested that the chemical reaction at the gas-solid interface between hydrogen and the manganese ore is likely the rate-limiting step in this process.展开更多
Iron tailings are a common solid waste resource,posing serious environmental and spatial challenges.This study proposed a novel hydrogen-based reduction roasting(HRR)technology for the processing of iron tailings usin...Iron tailings are a common solid waste resource,posing serious environmental and spatial challenges.This study proposed a novel hydrogen-based reduction roasting(HRR)technology for the processing of iron tailings using a combined beneficiation and metallurgy approach.Pilot-cale experiment results indicated that under the gas composition of CO:H_(2)=1:3,and optimal roasting conditions at a reduction temperature of 520℃,the majority of weakly magnetic hematite transforms into strongly magnetic magnetite during the reduction process.Combining roasting products with a magnetic separation-grinding-magnetic selection process yields a final iron concentrate with a grade of 56.68%iron and a recovery rate of 86.54%.Theoretical calculations suggested the annual production value can reach 29.7 million USD and a reduction of 20.79 tons of CO_(2) emissions per year.This highlights that the use of HRR in conjunction with traditional beneficiation processes can effectively achieve comprehensive utilization of iron tailings,thereby reducing environmental impact.展开更多
基金Project (2007CB613604) supported by the National Basic Research Program of China
文摘Ida2--H2O system（iminodiacetate aqueous solution） was used to leach a low grade zinc oxide ore for Zn extraction.The effects of leaching time,liquid-solid ratio（L/S）,total concentration of Ida2-（[Ida2-]T）,leaching temperature and pH on Zn leaching recovery and the dissolution of impurities such as Ca,Mg,Cu,Ni,Fe,Pb and Cd were investigated.Results show that Ca,Mg and Fe in ores were hardly dissolved in alkalescent iminodiacetate aqueous solution,while valuable metals such as Cu,Ni,Pb and Cd were partly dissolved into leaching liquor with Zn.The recovery of Zn reaches 76.6% when the ores were leached for 4 h at 70 ℃ by 0.9 mol/L iminodiacetate aqueous solution with pH of 8 and L/S of 5：1.
基金Project(51125018)supported by the National Natural Science Foundation for Distinguished Young Scholars of ChinaProject(51204153)supported by the National Natural Science Foundation of ChinaProject(2011BAC06B07)supported by the National High Technology Research and Development Program,China
文摘A novel process was proposed for the activation pretreatment of limonitic laterite ores by Na2CO3 roasting. Dechromization and dealumination kinetics of the laterite ores and the effect of particle size, Na2CO3-ore mass ratio, and roasting temperature on Cr and Al extraction were studied. Experimental results indicate that the extraction rates of Cr and Al are up to 99%and 82%, respectively, under the optimal particle size of 44–74μm, Na2CO3-to-ore mass ratio of 0.6：1, and temperature of 1000 ℃. Dechromization within the range of 600–800 oC is controlled by the diffusion through the product layer with an apparent activation energy of 3.9 kJ/mol, and that it is controlled by the chemical reaction at the surface within the range of 900–1100 ℃ with an apparent activation energy of 54.3 kJ/mol. Besides, the Avrami diffusion controlled model with on apparent activation energy of 16.4 kJ/mol is most applicable for dealumination. Furthermore, 96.8%Ni and 95.6%Co could be extracted from the alkali-roasting residues in the subsequent pressure acid leaching process.
基金supported by the National Natural Science Foundation of China(Grant No.52474347)Postdoctoral Science Foundation of China(Grant No.2024T171095)the Fundamental Research Funds for the Central Universities(Grant No.2024CDJXY003).
文摘Coke oven gas(COG)and natural gas(NG),both high-calorific by-products derived from the steel industry,have gained prominence as alternative fuels in the sintering process,thereby supporting dual objectives of emission reduction and carbon neutrality.While existing research on hydrogen-rich gas injection has predominantly concentrated on conventional thin-bed sintering,investigations into its application within thick-bed sintering remain comparatively scarce.Thick-bed sintering,recognized for enhancing energy efficiency and increasing sinter output,encounters challenges such as uneven heat distribution and diminished permeability,which can negatively impact process efficiency and product quality.To address these issues,sinter pot experiments were conducted to assess the effects of NG and COG injection on thick-bed sintering performance.Findings reveal that NG injection in thick beds mirrors the behavior observed in conventional thin-bed sintering,effectively optimizing the process and achieving a carbon reduction potential exceeding 10%.In contrast,COG injection in thick-bed conditions demonstrates notable differences,substantially lowering the solid fuel consumption rate but detrimentally affecting sinter strength and overall production.However,by optimizing the timing of COG injection,it is feasible to improve sinter yield while concurrently reducing solid fuel usage.These outcomes provide valuable insights for the advancement of gas injection technologies in thick-bed sintering,thereby contributing to energy conservation and emission mitigation efforts within the sintering industry.
基金Project(2182040)supported by the Beijing Natural Science Foundation,ChinaProjects(51674026,51974025,U1802253)supported by the National Natural Science Foundation of ChinaProject(FRF-TT-19-001)supported by the Fundamental Research Funds for the Central Universities,China。
文摘An innovative technology,nitric acid pressure leaching of limonitic laterite ores,was proposed by our research team.The HNO3 regeneration is considerable significance for the improvement of the proposed technology and its commercial application,but it has not been systematically investigated.Herein,regenerating HNO3 from Ca(NO3)2 solution with low-cost H2SO4,and simultaneous synthesis of fibrous CaSO4·2H2O by-products were studied.As a theoretical basis,the solubility of CaSO4·2H2O in HNO3 medium is studied.It is concluded that the solubility of CaSO4·2H2O increases with increasing temperature or increasing HNO3 concentration,which has considerable guiding significance for the subsequent experimental research and analysis.Then,the effects of various factors on the residual Ca^2+ concentration of filtrate,the regenerated HNO3 concentration and the morphology of synthesized products are investigated using ICP-AES and SEM.And the effect mechanism is also analyzed.The results indicate the regenerated HNO3 concentration reaches 116 g/L with the residual Ca^2+ concentration being 9.7 g/L at the optimum conditions.Moreover,fibrous CaSO4·2H2O by-products with high aspect ratios(length,406.32μm;diameter,14.71μm;aspect ratio,27.62)can be simultaneously synthesized.
基金financial support by the Fundamental Research Funds for the Central Universities(xjh012019019)the National Natural Science Foundation of China(51606087)。
文摘In the chemical looping with oxygen uncoupling(CLOU)process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combustion rate of carbon is faster than the decoupling rate of oxygen carrier(OC).Hence,high temperature tolerance and rapid oxygen release rate of CuO modified by three different ores were investigated in this study.The kinetics analysis of oxygen decoupling with Cu-based oxygen carriers was also evaluated.Results showed that CuO modified by chrysolite had faster oxygen release rate than that of CuO.Limestone showed obvious positive effect on the oxidization process.The selected OCs could keep stable in at least 20 cycles,for about 1200 min.Shrinking core model(SCM)fitted well for the decoupling process in the temperature range of 1123-1223 K.Reduction rate kinetic information may aid in the development of chemical looping with oxygen uncoupling(CLOU)technologies during reactor design and process modeling.Ternary doped copper oxide with chrysolite and limestone could improve the reactivity of CuO in decoupling and coupling process and also improve the high temperature tolerance.
基金supported by the National Natural Science Foundation of China(22179063,22479078,and 22409093)the Natural Science Foundation of Jiangsu Province of China(BK20240579)。
文摘FeS_(2)is a promising anode material for potassium-ion batteries(PIBs),with the advantages of low cost and high capacity.However,it still faces challenges of capacity fading and poor rate performance in potassium storage.Rational structural design is one way to overcome these drawbacks.In this work,MIL-88B-Fe-derived FeS_(2)nanoparticles/N-doped carbon nanofibers(M-FeS_(2)@CNFs)with expansion buffer capability are designed and synthesized for high-performance PIB anodes via electrospinning and subsequent sulfurization.The uniformly distributed cavity-type porous structure effectively mitigates the severe aggregation problem of FeS_(2)nanoparticles during cycling and buffers the volume change,further enhancing the potassium storage capacity.Meanwhile,the robust KF-rich solid electrolyte interphase induced by methyl trifluoroethylene carbonate(FEMC)additive improves the cycling stability of the M-FeS_(2)@CNF anode.In the electrolyte with 3 wt%FEMC,the M-FeS_(2)@CNF anode shows a reversible specific capacity of 592.7 mA h g^(-1)at 0.1 A g^(-1),an excellent rate capability of 327.1 mA h g^(-1)at 5 A g^(-1),and a retention rate 80.7%over 1000 cycles at 1 A g^(-1).More importantly,when assembled with a K_(1.84)Ni[Fe(CN)_(6)]_(0.88)·0.49H_(2)O cathode,the full battery manifests excellent cycle stability and high rate performance.This study demonstrates the significant importance of the synergistic effect of structural regulation and electrolyte optimization in achieving high cycling stability of PIBs.
基金supported by the Central South University Innovation-Driven Research Programme(No.2023CXQD009).
文摘Iron disulfide(FeS_(2))has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau.However,low thermal decomposition temperature,poor conductivity and inferior actual specific capacity limit its wide applications.Herein,we report a gold-doped FeS_(2)(FeS_(2)-Au),which not only reduces the band gap of the FeS_(2)crystals but also enriches the electron transport path of FeS_(2)by the formation of Au nanoparticles.First-principles calculation shows that the diffusion energy barrier of lithium-ion is reduced after the Au-doped FeS_(2).In addition,Au increases the electron cloud density around sulfur atoms,which helps to enhance the stability of Fe-S covalent bonds and thus results in better thermal stability of FeS_(2).When the Au content is 130μg·g^(-1)(FeS_(2)-Au_(4)),the thermal decomposition temperature(TG5%)of FeS_(2)-Au is 72.2℃ higher than that of pristine FeS_(2).At a discharge temperature of 500℃,a current density of 200 mA·cm^(-2) and a cutoff voltage of 1.4 V,FeS_(2)-Au_(4)demonstrates superior specific capacity and high specific energy compared to FeS_(2).More precisely,the specific capacity of FeS_(2)-Au_(4)attains a value of 379 mAh·g^(-1),with a corresponding specific energy of 714 Wh·kg^(-1).In contrast,the discharge specific capacity and specific energy of FeS_(2)are lower,amounting to 348 mAh·g^(-1)and 656 Wh·kg^(-1),respectively.This study offers a novel approach to enhancing the electrochemical performance of FeS_(2)in high-temperature molten salt electrochemical systems(thermal batteries),thereby laying a solid foundation for its potential practical application.
基金supported by the National Natural Science Foundation of China(No.52172206)the Project of Science&Technology Office of Jiangsu Province(No.KB20181043)the Talent Research Projects of Qilu University of Technology(Shandong Academy of Sciences)(No.2024RCKY018)。
文摘Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^(-)/h^(+) pairs together with the production of heat energy.However,the inefficient separation of charge carriers and inadequate response to near-infrared(NIR)light usually leads to the unsatisfactory photocatalytic efficiency,hindering their application potentials.In this work,a significantly enhanced photothermal catalytic hydrogen evolution reaction over the lead-free perovskite Cs_(3)Bi_(2)Br_(9)/FeS_(2)(CBB/FS)heterostructure is simultaneously verified,where the CBB/FS Z-scheme heterojunctions display the strong stability and superb photothermal catalytic activity.Under the simulated solar irradiation(AM 1.5G),the optimized CBB/FS-5 achieves a photocatalytic hydrogen evolution rate of 31.5 mmol g^(-1)h^(-1),which is 112.6 and 77.1 times higher than that of FS and CBB,respectively,together with an apparent quantum yield of 29.5%at 420 nm.This significantly improved photocatalytic H_(2)evolution can be mainly attributed to the Z-scheme charge transfer and photothermal-assisted synergistically enhanced photocatalytic H_(2)production,and the potential mechanism of the enhanced photocatalytic H_(2)evolution is also proposed by photoelectrochemical characterizations,in situ XPS,EPR spectra,and the DFT calculations.This work provides new insights to the design of high-efficient photothermal catalysts,leading to the sustainable and efficient solutions towards the energy and environmental challenges.
基金the financial support from European Union’s Horizon Europe program HAlMan project (No. 101091936)
文摘Replacing solid carbon with hydrogen gas in ferromanganese production presents a forward-thinking,sustainable solution to re-ducing the ferro-alloy industry’s carbon emissions.The HAlMan process,a groundbreaking and eco-friendly method,has been meticu-lously researched and scaled up from laboratory experiments to pilot tests,aiming to drastically cut CO_(2) emissions associated with ferro-manganese production.This innovative process could potentially reduce CO_(2) emissions by about 1.5 tonnes for every tonne of ferroman-ganese produced.In this study,a lab-scale vertical thermogravimetric furnace was used to carry out the pre-reduction of Nchwaning man-ganese ore,where direct reduction occurred with H_(2) gas under controlled isothermal conditions at 700,800,and 900℃.The results indic-ated that higher pre-reduction temperatures(800 and 900℃)effectively converted Fe_(2)O_(3) to metallic iron and Mn_(2)O_(3) to MnO.By continu-ously monitoring the mass changes during the reduction,both the rate and extent of reduction were assessed.A second-order reaction model was applied to validate the experimental outcomes of H_(2) reduction at various temperatures,showing apparent activation energies of 29.79 kJ/mol for dried ore and 61.71 kJ/mol for pre-calcined ore.The reduction kinetics displayed a strong dependence on temperature,with higher temperatures leading to quicker and more complete reductions.The kinetics analysis suggested that the chemical reaction at the gas-solid interface between hydrogen and the manganese ore is likely the rate-limiting step in this process.
基金National Natural Science Foundation of China(52104249)Liaoning Joint Fund General Support Program Project(2023-MSBA-126)the Fundamental Research Funds for the Central Universities(N2401019).
文摘Iron tailings are a common solid waste resource,posing serious environmental and spatial challenges.This study proposed a novel hydrogen-based reduction roasting(HRR)technology for the processing of iron tailings using a combined beneficiation and metallurgy approach.Pilot-cale experiment results indicated that under the gas composition of CO:H_(2)=1:3,and optimal roasting conditions at a reduction temperature of 520℃,the majority of weakly magnetic hematite transforms into strongly magnetic magnetite during the reduction process.Combining roasting products with a magnetic separation-grinding-magnetic selection process yields a final iron concentrate with a grade of 56.68%iron and a recovery rate of 86.54%.Theoretical calculations suggested the annual production value can reach 29.7 million USD and a reduction of 20.79 tons of CO_(2) emissions per year.This highlights that the use of HRR in conjunction with traditional beneficiation processes can effectively achieve comprehensive utilization of iron tailings,thereby reducing environmental impact.
