To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approac...To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approach aims to enhance the leaching efficiency of Fe from jarosite residue.The introduction of an electric field changes the charge distribution on the surface of the particles to enhance ions and electrons exchange and promotes the collision between particles to strengthen reaction kinetics.Based on the above,the leaching efficiency of Fe in jarosite under sulfuric acid attack has improved observably.The result shows that Fe leaching efficiency reaches 98.83%,which is increased by 28%under the optimal experimental conditions:current density of 30 mA·cm^(-2),H_(2)SO_(4) concentration of 1.5 mol·L^(-1),solid-liquid ratio of 70 g·L^(-1),temperature of 80℃ and time of 12 h.Leaching kinetics calculations show that the apparent activation energy is 16.97 kJ·mol^(-1) and the leaching of jarosite residue is controlled by a mixture of chemical reaction and diffusion,as well as the temperature and concentration of the leaching solution have an influence on leaching.This work provides a feasible idea for the efficient leaching of Fe from jarosite residue.展开更多
Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In thi...Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.展开更多
The concept of zero waste is an ideal situation that will require different solutions for different categories of waste.Electronic waste(E-waste),the fastest growing category of solid hazardous waste presents various ...The concept of zero waste is an ideal situation that will require different solutions for different categories of waste.Electronic waste(E-waste),the fastest growing category of solid hazardous waste presents various unique challenges.Electronic product repair,reuse and remanufacture(3re)are crucial for effective source reduction of E-waste and the integration of the electronics industry into a circular or zero-waste economy framework.Increasingly,3re implementation is restricted by regulatory difficulties,particularly the invocation of copyright laws.Here,we use the examples of electronic printer cartridges and restored compact discs(CDs)to identify the challenges and to explore solutions for managing the risks associated with E-waste through circular economy and the opportunities presented by innovative Blockchain solutions.A set of international consensuses on judicial definitions,such as 3re,refurbish fake/counterfeit product and copyright exhaustion,are proposed to accelerate source reduction in E-waste management toward the goal of zero waste.展开更多
Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH...Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O with suspension electrolysis,effectively converting poorly soluble PbSO_(4)into soluble[Pb(NH_(3))_(4)]^(2+)complexes.The electrolytic conversion mechanisms of SLP components are systematically elucidated,revealing four distinct transformation pathways:1)metallic Pb undergoes complete dissolution as[Pb(NH_(3))_(4)]^(2+)complexes followed by cathodic reduction to elemental lead;2)PbO_(2)increases after suspension electrolysis since part of PbO is oxidized;3)PbO demonstrates dual behavior,with 45.74%undergoing anodic oxidation to PbO_(2) while the remainder(54.26%)participates in cathodic electrodeposition;4)PbSO_(4)exhibits triple conversion routes,including:1)32.98%transformation through intermediate(NH_(4))Pb(OH)SO_(4)formation followed by anodic conversion to PbO·PbSO_(4),2)21.36%direct cathodic reduction to metallic lead,and 3)the residual fraction maintaining soluble[Pb(NH_(3))_(4)]^(2+)speciation in the electrolyte.The optimized process achieves exceptional current efficiency(95.49%)and lead recovery(45.67%),with anode residues comprising 67.58%PbO_(2)and 32.42%PbO·PbSO_(4).Remarkably,this process exhibits significant economic and environmental advantages,with recycling 1 kg of SLP through the(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O suspension electrolysis process resulting in a net profit of 0.3466 USD and a reduction in carbon emissions of 119.758 kg CO_(2)eq.,offering dual advantages of environmental and economic benefits.This work provides fundamental insights into lead phase conversion during suspension electrolysis while presenting a practical,effective solution for battery recycling industries.展开更多
基金The National Natural Science Foundation of China(22276153,51974262)funded this work。
文摘To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approach aims to enhance the leaching efficiency of Fe from jarosite residue.The introduction of an electric field changes the charge distribution on the surface of the particles to enhance ions and electrons exchange and promotes the collision between particles to strengthen reaction kinetics.Based on the above,the leaching efficiency of Fe in jarosite under sulfuric acid attack has improved observably.The result shows that Fe leaching efficiency reaches 98.83%,which is increased by 28%under the optimal experimental conditions:current density of 30 mA·cm^(-2),H_(2)SO_(4) concentration of 1.5 mol·L^(-1),solid-liquid ratio of 70 g·L^(-1),temperature of 80℃ and time of 12 h.Leaching kinetics calculations show that the apparent activation energy is 16.97 kJ·mol^(-1) and the leaching of jarosite residue is controlled by a mixture of chemical reaction and diffusion,as well as the temperature and concentration of the leaching solution have an influence on leaching.This work provides a feasible idea for the efficient leaching of Fe from jarosite residue.
基金supported by the Key Research and Development Program of Guangxi Province,China (No.AB23075174)the National Natural Science Foundation of China (No.52174386)the Science and Technology Plan Project of Sichuan Province,China (No.2022YFS0459).
文摘Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.
基金supported by a grant from the National Natural Science Foundation of China(Grant No.51974262)the Science&Technology Pillar Program of Sichuan Province(No.2019YFS0450)support from the Lincoln Dynamic Foundation’s World Institute for Sustainable Development of Materials(WISDOM).
文摘The concept of zero waste is an ideal situation that will require different solutions for different categories of waste.Electronic waste(E-waste),the fastest growing category of solid hazardous waste presents various unique challenges.Electronic product repair,reuse and remanufacture(3re)are crucial for effective source reduction of E-waste and the integration of the electronics industry into a circular or zero-waste economy framework.Increasingly,3re implementation is restricted by regulatory difficulties,particularly the invocation of copyright laws.Here,we use the examples of electronic printer cartridges and restored compact discs(CDs)to identify the challenges and to explore solutions for managing the risks associated with E-waste through circular economy and the opportunities presented by innovative Blockchain solutions.A set of international consensuses on judicial definitions,such as 3re,refurbish fake/counterfeit product and copyright exhaustion,are proposed to accelerate source reduction in E-waste management toward the goal of zero waste.
基金sponsored by the National Natural Science Foundation of China(No.22276153).The authors would like to thank the Shiyanjia Lab for the XRD test.
文摘Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O with suspension electrolysis,effectively converting poorly soluble PbSO_(4)into soluble[Pb(NH_(3))_(4)]^(2+)complexes.The electrolytic conversion mechanisms of SLP components are systematically elucidated,revealing four distinct transformation pathways:1)metallic Pb undergoes complete dissolution as[Pb(NH_(3))_(4)]^(2+)complexes followed by cathodic reduction to elemental lead;2)PbO_(2)increases after suspension electrolysis since part of PbO is oxidized;3)PbO demonstrates dual behavior,with 45.74%undergoing anodic oxidation to PbO_(2) while the remainder(54.26%)participates in cathodic electrodeposition;4)PbSO_(4)exhibits triple conversion routes,including:1)32.98%transformation through intermediate(NH_(4))Pb(OH)SO_(4)formation followed by anodic conversion to PbO·PbSO_(4),2)21.36%direct cathodic reduction to metallic lead,and 3)the residual fraction maintaining soluble[Pb(NH_(3))_(4)]^(2+)speciation in the electrolyte.The optimized process achieves exceptional current efficiency(95.49%)and lead recovery(45.67%),with anode residues comprising 67.58%PbO_(2)and 32.42%PbO·PbSO_(4).Remarkably,this process exhibits significant economic and environmental advantages,with recycling 1 kg of SLP through the(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O suspension electrolysis process resulting in a net profit of 0.3466 USD and a reduction in carbon emissions of 119.758 kg CO_(2)eq.,offering dual advantages of environmental and economic benefits.This work provides fundamental insights into lead phase conversion during suspension electrolysis while presenting a practical,effective solution for battery recycling industries.
