探索Nd(Ⅲ)离子在活性电极表面原位还原机制对优化熔盐电解制备Pr-Nd合金工艺过程具有重要的理论和现实意义。本研究采用扫描电化学显微技术(SECM)与计时电流分析相结合的方法,通过产生-收集模式原位分析Nd(Ⅲ)离子在不同电位条件下Ni...探索Nd(Ⅲ)离子在活性电极表面原位还原机制对优化熔盐电解制备Pr-Nd合金工艺过程具有重要的理论和现实意义。本研究采用扫描电化学显微技术(SECM)与计时电流分析相结合的方法,通过产生-收集模式原位分析Nd(Ⅲ)离子在不同电位条件下Ni阴极基体微区的电流响应及形核规律。结果表明,随着施加在Ni阴极基体表面电位在-0.6~-1.0 V (vs.Ag/AgCl)范围内负移,表面活性位点逐渐增多且分布更均匀,电流峰强度最高值由低于0.003μA逐渐增大至0.004μA。水溶液体系中激活的Nd(Ⅲ)离子在Ni阴极表面的二维形核区域不断增大,三维形核活性位点也不断增加且均匀分布。Nd(Ⅲ)离子在Ni基电极表面的主要形核方式为瞬时形核,Nd(Ⅲ)离子扩散系数约为8.57×10^(-9)m^(2)/s。展开更多
Owing to the worldwide trend towards carbon neutrality,the number of Dy-containing heat-resistant Nd magnets used for wind power generation and electric vehicles is expected to increase exponentially.However,rare eart...Owing to the worldwide trend towards carbon neutrality,the number of Dy-containing heat-resistant Nd magnets used for wind power generation and electric vehicles is expected to increase exponentially.However,rare earth(RE)elements(especially Dy)are unevenly distributed globally.Therefore,an environmental-friendly recycling method for RE elements with a highly precise separation of Dy and Nd from end-of-life magnets is required to realize a carbon-neutral society.As an alternative to traditional hydrometallurgical RE separation techniques with a high environmental load,we designed a novel,highly efficient,and precise process for the separation and recycling of RE elements from magnet scrap.As a result,over 90%of the RE elements were efficiently extracted from the magnets using MgCl_(2)and evaporation loss was selectively suppressed by adding CaF_(2).The extracted RE elements were electrolytically separated based on the formation potential differences of the RE alloys.Nd and Dy metals with purities greater than 90%were estimated to be recovered at rates of 96%and 91%,respectively.Almost all the RE in the scraps could be separated and recycled as RE metals,and the byproducts were easily removed.Thus,this process is expected to be used on an industrial scale to realize a carbon-neutral society.展开更多
Based on a non-equilibrium kinetic extraction technique,the complexation kinetics of diethylenetriamine-pentaacetic acid(DTPA)with rare earth(RE)ions was investigated with different adding sequences of DTPA.The result...Based on a non-equilibrium kinetic extraction technique,the complexation kinetics of diethylenetriamine-pentaacetic acid(DTPA)with rare earth(RE)ions was investigated with different adding sequences of DTPA.The results indicated that the separation factors ofβTm/Er andβY/Er were higher when adding DTPA at the start of extraction than those before extraction.The extraction order for Y,Er and Tm was Tm>Y>Er.The root of discrepancy in complexation kinetics of Y,Er and Tm ions with DTPA and the enhanced kinetic separation mechanism were elucidated from the forward complex formation and reverse dissociation rates by the stopped-flow spectrophotometric technique.The apparent complexation rate constants began to decrease gradually with the increase of aqueous pH,while increased with increasing DTPA concentration.The emergence of extraction priority order as Tm>Y>Er was verified according to the calculated reaction kinetic constants of Y,Er and Tm at different pH values.展开更多
明晰熔盐中氧化镧的溶解过程有助于电解过程电解质的选择和进料速度的控制。本研究采用物相分析与热分析方法探究了La_(2)O_(3)在LiF-LaF_(3)熔盐中的溶解机制,采用透明电解装置对La_(2)O_(3)在熔盐中的溶解过程进行了研究。结果表明,La...明晰熔盐中氧化镧的溶解过程有助于电解过程电解质的选择和进料速度的控制。本研究采用物相分析与热分析方法探究了La_(2)O_(3)在LiF-LaF_(3)熔盐中的溶解机制,采用透明电解装置对La_(2)O_(3)在熔盐中的溶解过程进行了研究。结果表明,La_(2)O_(3)在熔融盐中的溶解包括物理溶解和化学溶解,溶解过程表现为吸热;在LiF-LaF3熔盐中,LiF与LaF_(3)反应生成LaF_(2),La_(2)O_(3)溶解于LiF-LaF_(3)熔盐中会生成Li La O2和La OF。展开更多
文摘探索Nd(Ⅲ)离子在活性电极表面原位还原机制对优化熔盐电解制备Pr-Nd合金工艺过程具有重要的理论和现实意义。本研究采用扫描电化学显微技术(SECM)与计时电流分析相结合的方法,通过产生-收集模式原位分析Nd(Ⅲ)离子在不同电位条件下Ni阴极基体微区的电流响应及形核规律。结果表明,随着施加在Ni阴极基体表面电位在-0.6~-1.0 V (vs.Ag/AgCl)范围内负移,表面活性位点逐渐增多且分布更均匀,电流峰强度最高值由低于0.003μA逐渐增大至0.004μA。水溶液体系中激活的Nd(Ⅲ)离子在Ni阴极表面的二维形核区域不断增大,三维形核活性位点也不断增加且均匀分布。Nd(Ⅲ)离子在Ni基电极表面的主要形核方式为瞬时形核,Nd(Ⅲ)离子扩散系数约为8.57×10^(-9)m^(2)/s。
基金supported by a Grant-in-Aid from the Japan Society for the Promotion of Science(JSPS)Fellows(19J20301).
文摘Owing to the worldwide trend towards carbon neutrality,the number of Dy-containing heat-resistant Nd magnets used for wind power generation and electric vehicles is expected to increase exponentially.However,rare earth(RE)elements(especially Dy)are unevenly distributed globally.Therefore,an environmental-friendly recycling method for RE elements with a highly precise separation of Dy and Nd from end-of-life magnets is required to realize a carbon-neutral society.As an alternative to traditional hydrometallurgical RE separation techniques with a high environmental load,we designed a novel,highly efficient,and precise process for the separation and recycling of RE elements from magnet scrap.As a result,over 90%of the RE elements were efficiently extracted from the magnets using MgCl_(2)and evaporation loss was selectively suppressed by adding CaF_(2).The extracted RE elements were electrolytically separated based on the formation potential differences of the RE alloys.Nd and Dy metals with purities greater than 90%were estimated to be recovered at rates of 96%and 91%,respectively.Almost all the RE in the scraps could be separated and recycled as RE metals,and the byproducts were easily removed.Thus,this process is expected to be used on an industrial scale to realize a carbon-neutral society.
基金funded by Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources,China(No.2022IRERE206)financially supported by the National Natural Science Foundation of China(Nos.51904027,52074031)。
文摘Based on a non-equilibrium kinetic extraction technique,the complexation kinetics of diethylenetriamine-pentaacetic acid(DTPA)with rare earth(RE)ions was investigated with different adding sequences of DTPA.The results indicated that the separation factors ofβTm/Er andβY/Er were higher when adding DTPA at the start of extraction than those before extraction.The extraction order for Y,Er and Tm was Tm>Y>Er.The root of discrepancy in complexation kinetics of Y,Er and Tm ions with DTPA and the enhanced kinetic separation mechanism were elucidated from the forward complex formation and reverse dissociation rates by the stopped-flow spectrophotometric technique.The apparent complexation rate constants began to decrease gradually with the increase of aqueous pH,while increased with increasing DTPA concentration.The emergence of extraction priority order as Tm>Y>Er was verified according to the calculated reaction kinetic constants of Y,Er and Tm at different pH values.
文摘明晰熔盐中氧化镧的溶解过程有助于电解过程电解质的选择和进料速度的控制。本研究采用物相分析与热分析方法探究了La_(2)O_(3)在LiF-LaF_(3)熔盐中的溶解机制,采用透明电解装置对La_(2)O_(3)在熔盐中的溶解过程进行了研究。结果表明,La_(2)O_(3)在熔融盐中的溶解包括物理溶解和化学溶解,溶解过程表现为吸热;在LiF-LaF3熔盐中,LiF与LaF_(3)反应生成LaF_(2),La_(2)O_(3)溶解于LiF-LaF_(3)熔盐中会生成Li La O2和La OF。
