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Progress in green and efficient enrichment of rare earth from leaching liquor of ion adsorption type rare earth ores

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Journal of Rare Earths 2022年第3期40卷 353-364,I0001页

作者： Qiang He Jiang Qiu Jinfa Chen Miaomiao Zan yanfei xiao Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Ganzhou Engineering Technology Research Center of Green Metallurgy and Process Intensification Ganzhou 341000China

Ion adsorption type rare earth ores(IATREOs)are a valuable strategic mineral resource in China,which feature a complete composition of fifteen rare earth elements and are rich in medium and heavy rare earth(RE)elements.In the leaching process for recovering rare earth elements from IATREOs,many impurities will be leached together with rare earth elements and enter the leaching liquor.An impurity removal-precipitation enrichment technique is currently applied to selectively recovery rare earth elements from the leaching liquor with the high content of impurities and low concentration of rare earth elements by using ammonium bicarbonate in the industry.However,a high loss of rare earth elements and severe ammonia nitrogen pollution are caused by this process.Therefore,more beneficial impurities removal technologies,mainly for aluminum,and green enrichment technologies with lower pollution are now urgently needed.For this purpose,this paper analyzed two aspects of research progress in recent decades:the green separation of rare earth elements and aluminum from leaching liquor and the green and efficient enrichment of rare earth elements.Finally,an approach for the high-efficiency and green enrichment of rare earth elements from leaching liquor of the IATREOs is proposed in several aspects,including impurity inhibition leaching,neutralization and impurity removal,alkaline calcium and magnesium salt precipitation enrichment,and centrifugal extraction enrichment.

关键词： Ion adsorption type rare earth ores Leaching liquor Rare earth Aluminum Separation Non-ammonia enrichment

Insight into leaching of rare earth and aluminum from ion adsorption type rare earth ore:Adsorption and desorption

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稀土学报:英文版 2023年第9期41卷 1398-1407,I0005页

作者： Qiang He Jinfa Chen Limei Gan Menglan Gao Miaomiao Zan yanfei xiao Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Ganzhou Engineering Technology Research Center of Green Metallurgy and Process Intensification Ganzhou 341000China Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural ResourcesGanzhou 341oooChina Key Laboratory of Testing and Tracing of Rare Earth Products for State Market Regulation Ganzhou 34100oChina

Clay minerals are inferred to be the primary host materials for ion-exchangeable rare earth in ion adsorption type rare earth ore(IAREO).During the rare earth leaching process,the adsorption and desorption reactions of the cations controlling the leaching process continue to occur at the clay minerals-leaching agent solution interface.In order to understand the leaching mechanism and behavior of rare earth and co-leached aluminum,adsorption,competitive adsorption,and desorption experiments were carried out using kaolin as a typical clay mineral.The powerful electrostatic attraction and concentration driving forces facilitate the adsorption of cations.The adsorption ability and competitive adsorption ability of cations depend on their charge,hydration radius,and hydrolysis properties,and decrease in the order of La^(3+),Y^(3+),Al^(3+),Mg^(2+),and NH_(4)^(+).The desorption of rare earth and aluminum is positively affected by the concentration-driving force exerted by high concentrations of Mg^(2+) and NH_(4)^(+),with the order of the desorption ability being opposite to the adsorption ability.However,unspecified interactions between clay mineral particles enhanced by high-concentration desorbents,especially by Mg^(2+) than NH_(4)^(+),will adversely affect desorption reactions,which result in lower desorption efficiencies of rare earth and aluminum obtained with magnesium sulfate compared to those obtained with ammonium sulfate at high concentrations.Solid-phase Al(OH)_(3) generated at a high peak aluminum concentration leads to a considerably delayed aluminum efflux,thereby partially separating the rare earth from aluminum during the actual column leaching process.To advance the mining technology of IAREO by selectively improving the rare earth leaching efficiency with minimal leaching agent consumption,higher charged cations with concentrations limited to suitable levels should be preferred as leaching agents.

关键词： Rare earths Aluminum Kaolin Adsorption Desorption

Coordination-reduction leaching process of ion-adsorption type rare earth ore with ascorbic acid

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Journal of Rare Earths 2023年第8期41卷 1225-1233,I0004页

作者： Jinfa Chen Jiang Qiu Li Huang Xin Chen Ying Yang yanfei xiao Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Ganzhou Engineering Technology Research Center of Green Metallurgy and Process Intensification Ganzhou 341000China Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural ResourcesGanzhou 341000China Key Laboratory of Testing and Tracing of Rare Earth Products for State Market Regulation Ganzhou 341000China

The magnesium sulfate(MgSO_(4))-ascorbic acid(Vc)compound leaching technique can extract rare earth elements(REEs)existing in ion-exchangeable phase and colloidal phase from ion-adso rption type rare earth ore through the synergy effect of coordination and reduction,but its reaction process and mechanism remain unclear.In this paper,the coordination-reduction leaching mechanism was analyzed from the perspectives of leaching thermodynamics and kinetics,which provide theoretical guidance for the compound leaching process.In the case of neodymium,about 45%of dissolved neodymium will exist as the complex species of NdVc_(()3(aq))in Nd-Vc-sulfate system.Based on this,it is deduced that the Gibbs free energy of the leaching reaction of ion-exchangeable phase REEs will change to a more negative value through the coordination of REEs cations and Vc anions in the MgSO_(4)leaching process.In addition,the E_(h)-pH diagrams of Ce-SO_(4)^(2-)-H_(2)O and Fe-SO_(4)^(2-)-H_(2)O together with the dissolution experiments confirm that the added Vc initiates the leaching process of colloidal phase REEs through reduction-dissolution reaction.Through the study of leaching kinetics,the leaching of REEs is controlled by diffusion and chemical reaction in the co mpound leaching system since colloidal phase REEs are leached.Therefore,the addition of Vc can shift the leaching equilibrium to a more favorable state and accelerate leaching process.The rare earth leaching efficiency of ion-exchangeable phase and colloidal phase can be effectively improved by increasing the reaction temperature,the conce ntrations of leaching agent and Vc,and the leaching agent acidity.

关键词： Ion-adsorption type rare earth ore Ascorbic acid Coordination Reduction Leaching Mechanism

Recovery of rare earths from ion-absorbed rare earths ore with MgSO_4-ascorbic acid compound leaching agent

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Journal of Rare Earths 2018年第5期36卷 521-527页

作者： Fuguo Lai Li Huang Guohua Gao Run Yang yanfei xiao School of Metallurgical and Chemical Engineering Jiangxi University of Science and Technology Institute of Engineering & Research Jiangxi University of Science and Technology

The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable phase.Moreover, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO4 and environmentally friendly leaching.

关键词： Rare earth Leaching MgSO4 Ascorbic acid Ion-absorbed rare earths ore

Non-ammonia enrichment of rare earth by magnesium oxide from rare earth leaching liquor in magnesium salt system

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Journal of Rare Earths 2019年第8期37卷 886-894,I0004页

作者： Li Huang Guohua Gao Ran Wu Qian Zhang Fuguo Lai yanfei xiao School of Metallurgical and Chemical Engineering Jiangxi University of Science and TechnologyGanzhou 341000China Institute of Engineering&Research Jiangxi University of Science and TechnologyGanzhou 341000China

In order to solve the problem of ammonia-nitrogen pollution in the enrichment process of the ionadsorption type rare earth ore,the technology of non-ammonia precipitation with magnesium oxide precipitant was carried out.It is determined that the rare earth precipitation efficiency is 99.6%and the purity of rare earth concentrates is only 85.89 wt%under the optimum precipitation conditions.And the contents of MgO,SO3 and Al2O3 in the rare earth concentrates are 5.12 wt%,6.77 wt%and 1.78 wt%,respectively.Furthermore,the thermo-decomposition process of precipitates was investigated by TGDSC,XRD and FI-IR.The thermal decomposition process consists of two stages:the dehydration of rare earth hydroxide and alkaline rare earth sulfate within 900℃and the thermal decomposition of RE2O2SO4 at 900-1300℃.Therefore,a high-temperature calcinations method for removing SO3 from precipitates is proposed.When the precipitates are calcined at 1300℃for 2 h,the rare earth concentrates with a purity of 92.03 wt%can be acquired.Moreover,the content of SO3 in the concentrate is only 0.46 wt%.In the MgO precipitation and high-temperature calcinations process,the raw material cost is low and the quality of rare earth concentrates is acceptable.It could have great significance for nonammonia enrichment of rare earth from the rare earth leaching liquor,and finally solve the problem of ammonia nitrogen in the extraction process of the ion-adsorption type rare earth ore within magnesium salt system.

关键词： Non-ammonia Enrichment Magnesium oxide Ion-adsorption type rare earth ore

Effects of organic acids on the leaching process of ion-adsorption type rare earth ore

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Journal of Rare Earths 2017年第12期35卷 1233-1238页

作者： Li Wang Chunfa Liao Youming Yang Haibo Xu yanfei xiao Chunhua Yan School of Metallurgy and Chemical Engineering Jiangxi University of Science and Technology Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry College of Chemistry and Molecular Engineering Peking University

To examine the activation of organic acids on the leaching process of ion-adsorption type rare earth ore（IRE-ore）, the leaching behavior of rare earth（RE） and zeta potential of IRE-ore were investigated in the absence and presence of carboxylic acids. The results show that all the tested organic acids（acetic acid,malonic acid, citric acid, tartaric acid, succinic acid, and malic acid） can promote RE extraction. At relatively high concentrations of organic acids, the activation efficiency of organic acids on RE extraction is generally consistent with their complexation ability; whereas at their low concentrations, the change of zeta potential on the IRE-ore surface with organic acid concentration and p H has a close association with RE extraction, which indicates that organic acids can impact the surface electrical property of IREore via their adsorption/desorption, and thereby increase/decrease the affinity of RE ions to IRE-ore.Therefore the influence of organic acids on the IRE-ore surface electrical property also plays an important role in RE extraction in addition to their complexation with RE ions.

关键词： Ion-adsorption type rare earth ore Organic acid RE extraction Zeta potential Complexation

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等离子喷涂熔滴铺展凝固行为研究现状

材料导报 2024年第6期38卷 179-190页

作者：肖嵩刘明张小龙黄艳斐王海斗三峡大学机械与动力学院湖北宜昌443002 中国人民解放军陆军装甲兵学院装备再制造技术国防科技重点实验室北京100072

等离子喷涂实质上是以等离子气体为热源,将金属或陶瓷粉末加热成具有一定温度和速度的熔滴,并撞击基体表面而在基体上铺展凝固的过程,该过程对涂层质量具有重要影响。本文从单个和多个熔滴的铺展凝固行为、铺展凝固的影响因素以及熔滴... 详细信息

等离子喷涂实质上是以等离子气体为热源,将金属或陶瓷粉末加热成具有一定温度和速度的熔滴,并撞击基体表面而在基体上铺展凝固的过程,该过程对涂层质量具有重要影响。本文从单个和多个熔滴的铺展凝固行为、铺展凝固的影响因素以及熔滴凝固时产生键合和裂纹的原因三个方面,综述了等离子喷涂过程中熔滴撞击、铺展、凝固过程。当冷却速率不同时,熔滴撞击基体后会出现先铺展后凝固和边铺展边凝固两种行为;由于后续熔滴撞击位置的不同,材料会出现不同类型的孔隙;由于晶格参数和过冷度的不同,凝固方式主要有非稳态凝固和外延生长;影响铺展凝固的因素有气体捕获、熔滴底层凝固和基体预热等;提高粒子温度和基体温度、减少基体传热可以促进凝固过程中界面结合;合适的分段裂纹密度可以显著提升涂层性能。通过研究熔滴铺展凝固行为和堆叠过程,可以明确涂层内部缺陷的形成原因,完善对涂层形成机理的认识,更加科学地指导涂层质量调控。

关键词：等离子喷涂铺展行为凝固机理衬底温度冶金结合裂纹

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组分比例对闪沸射流相变诱导激波宽度的影响

工程热物理学报 2024年第3期45卷 748-754页

作者：许鹿冰徐海丰李雁飞马骁帅石金清华大学智能绿色车辆与交通全国重点实验室北京100084

闪沸射流发生欠膨胀并诱发激波间相互作用是汽油直喷喷油器的喷雾坍塌的主要原因,但液体组分比例对闪沸诱导激波的影响特性和机制尚不清楚。利用纹影法,在定容弹中研究了闪沸条件下乙醇/正己烷混合比例对激波宽度的影响,喷射温度(Tinj)... 详细信息

闪沸射流发生欠膨胀并诱发激波间相互作用是汽油直喷喷油器的喷雾坍塌的主要原因,但液体组分比例对闪沸诱导激波的影响特性和机制尚不清楚。利用纹影法,在定容弹中研究了闪沸条件下乙醇/正己烷混合比例对激波宽度的影响,喷射温度(Tinj)从30℃到150℃,环境压力(Pamb)从10 kPa到200 kPa。结果表明,提升喷射温度和减小环境压力,均会增加激波宽度。在相同喷射温度和环境压力下,乙醇含量增加会导致激波宽度呈现先增后减趋势,其主要是因为相变吉布斯能差(∆G)随乙醇含量增加呈现类似规律;通过进一步量化∆G和激波宽度的关系,发现激波宽度和∆G·P_(amb)^(-0.5)强线性相关,表明闪沸射流的激波宽度受到相变与环境阻力的控制。

关键词：闪沸欠膨胀射流激波双组分液体组分比例

Visualization Analysis for Business Performance of Chinese Listed Companies Based on Gephi

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Computers, Materials & Continua 2020年第5期63卷 959-977页

作者： Guang Sun Hongzhang Lv Dianyu Wang xiaoping Fan Yi Zuo yanfei xiao Xu Liu Wenqian Xiang Ziyi Guo Institute of Big Data Hunan University of Finance and EconomicsChangsha410205China Housheng School of International Education Hunan University of Finance and EconomicsChangsha410205China School of Information Science and Engineering Central South UniversityChangsha410075China School of Finance and Economics Hunan University of Finance and EconomicsChangsha410205China

When conducting company performance evaluations,the traditional method cannot reflect the distribution characteristics of the company’s operating conditions in the entire securities market.Gephi is an efficient tool for data analysis and visualization in the era of big data.It can convert the evaluation results of all listed companies into nodes and edges,and directly display them in the form of graphs,thus making up for the defects of traditional methods.This paper will take all the listed companies in the Shanghai and Shenzhen Stock Exchange as the analysis object.First uses tushare and web crawlers to collect the financial statement data of these companies.And then,uses the Economic Value Added model to calculate the EVA of each listed company and build graph data.Next,import the graph data into gephi to generate the distribution graph of all listed companies’performance,and summarize the distribution characteristics of business performance.Finally,select a listed company that you want to analyze in detail,using the traditional DuPont analysis method to conduct micro level visualization analysis of the business performance to find the main factors affecting the company’s operating performance.Incorporating gephi into traditional performance analysis methods will make the results of traditional analytical methods more effective and complete.

关键词： EVA gephi visualization graph analysis business performance evaluation