喷雾热解法是制备纳米CeO_(2)粉体的途径之一,但液滴在高速高温气流中发生的蒸发、破碎和热解行为影响了最终产品的性能和品质。本文基于VOF(Volume of fluid)蒸发传质模型与有限速率化学反应模型的耦合方法,研究了热解中液滴形貌以及...喷雾热解法是制备纳米CeO_(2)粉体的途径之一,但液滴在高速高温气流中发生的蒸发、破碎和热解行为影响了最终产品的性能和品质。本文基于VOF(Volume of fluid)蒸发传质模型与有限速率化学反应模型的耦合方法,研究了热解中液滴形貌以及流场的变化和产物分布随时间的全过程。结果表明:当入口气流速度为60 m/s、温度为650℃时,液滴在破碎前的形貌发生了变化,即液滴表面先出现波纹状起伏,然后加剧为褶皱状起伏,最后转变为沟壑状起伏;液滴迎风面与背风面存在压力差,流场中局部(液滴边缘)气流速度最大为67 m/s;子液滴数量沿X轴正方向不断减少且周围有产物CeO_(2)生成,计算域内产物CeO_(2)含量随时间的延长而逐渐增大;产物CeO_(2)主要生成于气相与氧化剂的交界面处,而非直接附着在液滴表面。展开更多
This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage(AMD)streams to recover rare earth elements(REEs).A life cycle assessment(...This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage(AMD)streams to recover rare earth elements(REEs).A life cycle assessment(LCA)study was done to evaluate the environmental impacts of rare earth production from deleterious material in the form of highly contaminated leachate(HCL)and low-contaminated leachate(LCL).The results indicate that the main contributors to environmental categories that produce RE-hydroxide stages are NaOH and electricity.Also,oxalic acid,Na_(2)CO_(3),and hydrochloric acid significantly contribute to the production stage of individual rare earth oxides(REOs),including solvent extraction(SX)and precipitation steps.The HCL route has higher environmental impacts than LCL due to higher chemical/energy and H_(2)SO_(4)usage,so 468 and 292 kg of carbon dioxide are generated to produce1 t of individual REOs from HCL and LCL routes,respectively.Moreover,the carbon dioxide emitted from the process,including the RE-hydroxide production,SX,and REOs production,is less than 10 t CO_(2).A sensitivity analysis was also performed to assess the changeability of the environmental footprints of the main inputs in the SX process,as the main stage has a higher contribution to the whole process.This LCA study is the first step toward understanding the environmental influence of new processing methods to produce REEs from coal by-products through a developed pilot-scale process.展开更多
Cerium(Ce) compounds have attracted considerable attention as key components in functional coatings due to their many outstanding properties.This work provides a comprehensive review of recent advances in the applicat...Cerium(Ce) compounds have attracted considerable attention as key components in functional coatings due to their many outstanding properties.This work provides a comprehensive review of recent advances in the application of Ce in functional coatings.The role of Ce in the improvement of functional properties such as corrosion-resistance,self-healing,superhydrophobicity,wear-resistance,and UV shielding is reviewed from the perspective of functional mechanism and applied research.Furthermore,the strategies,processes,practical problems,and current challenges in the research of functional coatings containing Ce are summarized and discussed.The objective is to highlight the great potential of Ce in functional coatings,and to explore new applications of Ce in the development of novel coatings.Thus,this work aims to enhance the application value of Ce,solving the problem of unbalanced application of rare-earth elements.展开更多
This article briefly reviews the major research progress of 9 typical material fields,including rare earth luminescence materials,catalysis,rare earth materials for biomedical applications,magnetic materials,optical c...This article briefly reviews the major research progress of 9 typical material fields,including rare earth luminescence materials,catalysis,rare earth materials for biomedical applications,magnetic materials,optical crystals,molecular-based materials,energy materials,metals and alloys,as well as rare earth extraction,separation and recycling in the year 2024.The aim of the review is to summarize the past and look into the future,and it will provide a basic overview of domestic work in related fields last year.Due to the abundance of content,the review strives to be concise.展开更多
文摘喷雾热解法是制备纳米CeO_(2)粉体的途径之一,但液滴在高速高温气流中发生的蒸发、破碎和热解行为影响了最终产品的性能和品质。本文基于VOF(Volume of fluid)蒸发传质模型与有限速率化学反应模型的耦合方法,研究了热解中液滴形貌以及流场的变化和产物分布随时间的全过程。结果表明:当入口气流速度为60 m/s、温度为650℃时,液滴在破碎前的形貌发生了变化,即液滴表面先出现波纹状起伏,然后加剧为褶皱状起伏,最后转变为沟壑状起伏;液滴迎风面与背风面存在压力差,流场中局部(液滴边缘)气流速度最大为67 m/s;子液滴数量沿X轴正方向不断减少且周围有产物CeO_(2)生成,计算域内产物CeO_(2)含量随时间的延长而逐渐增大;产物CeO_(2)主要生成于气相与氧化剂的交界面处,而非直接附着在液滴表面。
文摘This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage(AMD)streams to recover rare earth elements(REEs).A life cycle assessment(LCA)study was done to evaluate the environmental impacts of rare earth production from deleterious material in the form of highly contaminated leachate(HCL)and low-contaminated leachate(LCL).The results indicate that the main contributors to environmental categories that produce RE-hydroxide stages are NaOH and electricity.Also,oxalic acid,Na_(2)CO_(3),and hydrochloric acid significantly contribute to the production stage of individual rare earth oxides(REOs),including solvent extraction(SX)and precipitation steps.The HCL route has higher environmental impacts than LCL due to higher chemical/energy and H_(2)SO_(4)usage,so 468 and 292 kg of carbon dioxide are generated to produce1 t of individual REOs from HCL and LCL routes,respectively.Moreover,the carbon dioxide emitted from the process,including the RE-hydroxide production,SX,and REOs production,is less than 10 t CO_(2).A sensitivity analysis was also performed to assess the changeability of the environmental footprints of the main inputs in the SX process,as the main stage has a higher contribution to the whole process.This LCA study is the first step toward understanding the environmental influence of new processing methods to produce REEs from coal by-products through a developed pilot-scale process.
文摘Cerium(Ce) compounds have attracted considerable attention as key components in functional coatings due to their many outstanding properties.This work provides a comprehensive review of recent advances in the application of Ce in functional coatings.The role of Ce in the improvement of functional properties such as corrosion-resistance,self-healing,superhydrophobicity,wear-resistance,and UV shielding is reviewed from the perspective of functional mechanism and applied research.Furthermore,the strategies,processes,practical problems,and current challenges in the research of functional coatings containing Ce are summarized and discussed.The objective is to highlight the great potential of Ce in functional coatings,and to explore new applications of Ce in the development of novel coatings.Thus,this work aims to enhance the application value of Ce,solving the problem of unbalanced application of rare-earth elements.
文摘This article briefly reviews the major research progress of 9 typical material fields,including rare earth luminescence materials,catalysis,rare earth materials for biomedical applications,magnetic materials,optical crystals,molecular-based materials,energy materials,metals and alloys,as well as rare earth extraction,separation and recycling in the year 2024.The aim of the review is to summarize the past and look into the future,and it will provide a basic overview of domestic work in related fields last year.Due to the abundance of content,the review strives to be concise.
