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Aqueous stability of rare earth and thorium elements during hydrochloric acid leaching of roasted bastnaesite

Journal of Rare Earths 2017年第12期35卷 1255-1260页

作者： Genghong Shuai longsheng zhao Liangshi Wang Zhiqi Long Dali Cui National Engineering Research Center for Rare Earth Materials General Research Institute for Non-Ferrous Metals Grirem Advanced Materials Co. Ltd.

In order to study the aqueous stability of rare earth and thorium elements and the reaction mechanism of hydrochloric acid leaching of roasted bastnaesite,Eh-pH diagrams for La-,Nd-,Ce-,Th-（Cl）-（F）-H2 O systems at 20 ℃ were depicted using HSC Chemistry 6.0 software. Eh-pH diagrams of La-, Ce-,Nd-and Th-Cl-H2 O systems show that trivalent rare earth would be leached into solution by adjusting the acidity of the leaching solution, while tetravalent cerium and thorium would be remained in the leaching residue. And in the case that the pH value of the leaching solution is lower than 2, tetravalent cerium would be partially reduced by chlorine ions（Cl^-）, which is well agreed with the industrial production. It can be inferred from Eh-pH diagrams for the systems La-, Nd-,Ce-, Th-F-H2 O that the leached trivalent rare earth ions（RE^（3＋）） and tetravalent thorium ions（Th^（4＋）） are preferentially combined with fluorine ions（F） to form sediment during non-reductive acid leaching of roasted bastnaesite. However,when controlling the pH value of the leaching solution below 0, fluorine and tetravalent cerium in the roasted bastnaesite would be leached out in the form of soluble [CeF3]~＋ complex. That means the precipitation of REF3 and ThF4·2.5 H2 O can be avoided in the leaching step. According to Eh-pH diagrams for the system Ce-F-Cl-H2 O, [CeF3]~＋ in the leaching solution would be reduced to CeF3 precipitate in the presence of Cl^-, that is to say, tetravalent cerium and fluorine would be firstly leached out to form[CeF3]~＋,which would then be reduced to CeF3 precipitate by Cl^-in the hydrochloric acid leaching process of roasted bastnaesite.

关键词： Bastnaesite Eh-pH diagram Hydrochloric acid leaching Rare earth separation

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Thermal decomposition and oxidation of bastnaesite concentrate in inert and oxidative atmosphere

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Journal of Rare Earths 2018年第7期36卷 758-764页

作者： longsheng zhao Liangshi Wang Genghong Shuai Zhiqi Long Dali Cui Xiaowei Huang National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous MetalsBeijing 100088China Grirem Advanced Materials Co.Ltd. Beijing 100088China

To clearly elucidate the oxidative roasting behaviors of the bastnaesite, the thermal decomposition and oxidation of the bastnaesite concentrate in inert and oxidative atmosphere have been investigated in detail. Experimental data indicated that the initial decomposition temperature of the concentrate under N2 atmosphere is 150 ℃ higher than that under O2 atmosphere,most likely because the oxidation of the cerium induces the decomposition of the concentrate. For the roasted samples under N2 atmosphere at500 ℃ and above,the oxidation efficiency of the cerium is 19.8%-26.8% because of the fact that rareearth fluorocarbonate is first decomposed to form rare-earth oxyfluoride and CO2, and the cerium oxyfluoride is then partially oxidized by the CO2 gas. The rest cerium in these samples can be further oxidized in air at room temperature, with the oxidation efficiency of the cerium gradually increasing to above 80% in 7 d. This can be attributed to the obvious changes in the inner morphology of the roasted samples under N2 atmosphere at high temperatures, which largely induce the diffusion of the air and improves the oxidation activity of CeOF, and further induces the oxidation of CeOF by the air. XRD and XPS techniques were used to further verify the significant differences in the thermal decomposition behaviors of the bastnaesite concentrate under N2 and O2 atmosphere. Moreover, no oxidation of Pr^（3＋） to Pr^（4＋） in the roasted samples under both N2 and O2 atmosphere is observed. This gives an overall understanding of the oxidative roasting of the bastnaesite concentrate without additives.

关键词： Bastnaesite Thermal decomposition Oxidation Inert atmosphere Oxidative atmosphere Rare earths

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Occurrence and vertical distribution of aluminum and rare earths in weathered crust elution-deposited rare earth ore:Effect of soil solution pH and clay minerals

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Journal of Rare Earths 2024年第7期42卷 1394-1402,I0007页

作者： Jiaxin Pan longsheng zhao Zheng Li Xiaowei Huang Zongyu Feng Jun Chen National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China GRIREM Hi–Tech Co. Ltd.Langfang065201China GRIREM Advanced Materials Co. Ltd.Beijing100088China GRIMAT Engineering Institute Co. Ltd.Beijing101407China

Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most common mining *** high contents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A comprehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ *** paper improves a five-step sequential extraction method to analyze the occurrence and vertical distribution of rare earths and aluminum in vertical profiles from Chongzuo and *** results demonstrate that soil solution pH is the main factor affecting the vertical distribution of ionexchangeable rare *** samples have distinct areas of enrichment for ion-exchangeable rare earths or ***-exchangeable rare earths are primary concentrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micromorphology and particle size of the clay *** inorganic hydroxy aluminum concentration in Chongzuo samples decreases continuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the concentration in Longyan samples(110.55-171.27 mg/kg)is almost independence with sampling *** results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the consumption of leaching agent.

关键词： Weathered crust elution-deposited rare earth ore Sequential extraction Occurrence Aluminum Rare earth elements

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Preparation of crystalline mixed rare earth carbonates by Mg(HCO3)2 precipitation method

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Journal of Rare Earths 2020年第3期38卷 292-298页

作者： Zonghe Yu Meng Wang Liangshi Wang longsheng zhao Zongyu Feng Xu Sun Xiaowei Huang National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous MetalsBeijing 100088China Grirem Advanced Materials Co. Ltd.Beijing 100088China

In acid treatment technology of Baotou mixed rare earth ore,large quantities of ammonia-nitrogen wastewater are produced in the step of ammonium bicarbonate precipitation to transform rare earth *** this paper,we adopted a green precipitant magnesium bicarbonate(Mg(HCO3)2) to substitute ammonium bicarbonate to eliminate ammonia-nitrogen *** effects of n(HCO3^-):n(RE^3+),aging temperature and aging time on the crystallization using Mg(HCO3)2 precipitation method were *** results indicate that the rare earths could be completely recovered when n(HCO3^-):n(RE^3+) is higher than 3.15:*** crystal water content of rare earth carbonates is affected by the aging *** precipitate has a bad filterability when the aging temperature is over 40℃.This can be attributed to the less crystallized water molecules of the hydrated rare earth carbonate *** mixed rare earth carbonates are prone to be crystalline,and have a good filterability at aging temperatures below 40℃.Meanwhile,the evolution mechanism of crystalline mixed rare earth carbonates is reasonably deduced,the amorphous rare earth carbonates are first dissolute and then *** the optimized aging conditions,the purity of the crystalline precipitate meets the requirements of the fine product standard(GB/T 16479-2008).The filtrated could be used to produce Mg(HCO3)2,thus to realize the recycling of magnesium sulfate.

关键词： Baotou mixed rare earth ore Magnesium bicarbonate Rare earth carbonates Ammonia-free Crystallization mechanism Filtrate recycling

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Effects ofiron and temperature on solubility of light rare earth sulfates in multicomponent system of Fe2(SO4)3-H3PO4-H2SO4 synthetic solution

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Journal of Rare Earths 2020年第11期38卷 1243-1250,I0004页

作者： Shiliang Chen longsheng zhao Meng Wang Zongyu Feng Chao Xia Yang Xu Xiaowei Huang National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd.Beijing 100088China Grirem Advanced Materials Co. Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China School of Metallurgy Northeastern UniversityShenyang 110819China

Numerous light rare earth elements(LREE)minerals containing Fe and P were processed by sulfuric acid roasting method,and the leaching solution mainly comprises LREE sulfate,Fe2(SO4)3,H3PO4,and H2SO4,however,the solubility data of LREE sulfates in this system is *** work studies the solubility of LREE sulfates in independent LREE sulfate system RE2(SO4)3-Fe2(SO4)3-H3 PO4-H2SO4(RE=La,Ce,Pr or Nd)and mixed LREE sulfates system(La,Ce,Pr,Nd)2(SO4)3-Fe2(SO4)3-H3 PO4-H2SO4 at different temperature(25-65℃)and concentrations of Fe2(SO4)3(Fe2 O3,0-50.13 g/L),H2SO4(0.5 mol/L),and H3 PO4(P2 O5,20.34 g/L)based on the industrial operating condition at low liquid and solid ratio 2:*** solubility of each LREE sulfate in the independent system(La2 O3,12.25-20.88 g/L;CeO2,41.93-62.35 g/L;Pr6 O11,37.34-56.69 g/L;Nd2 O3,26.60-37.63 g/L)is much higher than that of the mixed system(La2 O3,6.95-11.03 g/L;CeO2,10.63-21.51 g/L;Pr6 O11,11.56-20.36 g/L;Nd2 O3,12.36-19.79 g/L)under the same other *** results also indicate that,in the two systems,both Fe and the temperature have negative effects on the solubility of LREE *** may occur due to the complication reactions between the complexes of RESO4+and Fe(SO4)2-.However,the influence degree of temperature and iron concentration on the LREE sulfates solubility varies in the two systems and among different LREE *** research is of theoretical significance for optimizing the conditions of the sulfuric acid process for recovering the LREE from the mixed LREE bearing minerals as well as the single LREE containing secondary rare earth scraps.

关键词： Rare earth sulfate Solubility Ferric sulfate Sulfuric acid Phosphoric acid

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Extraction mechanism and separation behaviors of low-concentration Nd^(3+) and Al^(3+) in P507-H_(2)SO_(4) system

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Journal of Rare Earths 2022年第6期40卷 952-957,I0004页

作者： Hongyuan Zhang longsheng zhao Xudong Zheng Depeng Liu Zongyu Feng Yongqi Zhang Xiaowei Huang National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China Grirem Advanced Materials Co. Ltd.Beijing 100088China Rare Earth Functional Materials(Xiong’an)Innovation Center Co. Ltd.Baoding 071700China

In order to clarify the solvent extraction and separation behaviors of rare earths and impurity of Al during the extraction and enrichment of low-concentration leach solution of ion-adsorption rare earth ore,the extraction mechanism and separation behaviors of Nd^(3+)and Al^(3+)in the Nd_(2)(SO_(4))_(3)-AI_(2)(SO_(4))_(3) mixed solution using P507 were studied in this *** extraction of Nd^(3+)and Al^(3+)follows the cation exchange *** the increase of the equilibrium pH,β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution using P507 is always higher than that in the extraction of single Nd_(2)(SO_(4))_(3) and Al_(2)(SO_(4))_(3) *** can be attributed to the fact that the extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),and Al^(3+)is more prone to be hydrolyzed at lower pH.β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution decreases gradually with the increase of mixing time within the equilibrium pH range of *** extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),but the stability of Al^(3+)-Ioaded organic phase is better than that of Nd^(3+)-loaded organic phase,thus Nd^(3+)in the Nd^(3+)-loaded organic phase is gradually replaced by Al^(3+)in the aqueous phase with the increase of mixing time.

关键词： Ion-adsorption rare earth ore Low-concentration rare earth Aluminum Extraction mechanism Separation factor

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Precipitation-dissolution behaviors of rare earth ions in H_3PO_4-Ca(H_2PO_4)_2 solutions

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Journal of Rare Earths 2019年第5期37卷 520-527页

作者： Shengxi Wu longsheng zhao Liangshi Wang Xiaowei Huang Yunhan Zhang Zongyu Feng Dali Cui National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals School of Metallurgical and Ecological Engineering University of Science and Technology Beijing (USTB)

In order to achieve deeper understanding of rare earth elements(REEs) behaviors during phosphate rock processing with H_3PO_4. The solubility of REEs in Ca(H_2PO_4)_2-H_3PO_4 solutions with various concentrations of Ca(H_2PO_4)_2 at different temperatures were tested. The results demonstrate that REEs solubility decreases sharply with the increasing concentration of Ca(H_2PO_4)_2. Equations between [REE^(3+)] and [H^+],[H^+] and [Ca^(2+)] in Ca(H_2PO_4)_2-H_3PO_4 solutions were built based on the precipitation-dissolution equilibrium of rare earth phosphates and the ionization equilibrium of H_3PO_4. According to the equations, the decreasing mechanism of REEs solubility caused by elevated concentration of Ca(H_2PO_4)_2 was determined. The mechanism can be illustrated as that the elevated concentration of [H_2 PO_4^-] decreases the concentration of hydrogen ion by retarding the ionization process of H_3PO_4 and directly promotes the precipitation of rare earth phosphates. Furthermore, it can be easy deduced that similar effect would be caused by the other cation impurities(Fe^(3+), Al^(3+), etc.) on REEs solubility based on the mechanism. In addition, superimposed reduction effect on REEs solubility caused by the elevated concentration of Ca(H_2PO_4)_2 and the elevated temperature is found. This superimposed effect leads to a super low solubility of REEs in Ca(H_2PO_4)_2-H_3PO_4 solution. On the basis of the experimental study, outlooks and suggestions for further development of REEs recovery method are given.

关键词： Rare earth elements Phosphoric acid Monocalcium phosphate Solubility Temperature

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Simultaneous recovery of rare earth elements and phosphorus from phosphate rock by phosphoric acid leaching and selective precipitation:Towards green process

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Journal of Rare Earths 2019年第6期37卷 652-658页

作者： Shengxi Wu longsheng zhao Liangshi Wang Xiaowei Huang Yunhan Zhang Zongyu Feng Dali Cui National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd. School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

Phosphate rock has been considered as one of the potential promising resources for rare earth elements(REEs). But the cost issues and the technical challenges caused by the low content of REEs in ores did hinder the further development of REEs recovery technologies. In order to explore a green process for the recovery of REEs from phosphate rock, this study investigates the effects of phosphoric acid concentration, liquid-to-solid ratio(L/S ratio), leaching time and temperature on the leaching efficiencies of the major components from phosphate rock. A REEs recovery of 94.3% and a phosphorus recovery of 95.3%are achieved under the optimal conditions of attacking phosphate rock using 30%P_2 O_5 acid with an L/S ratio of 10:1 and a stirring speed of 250 r/min at 25 ℃ for 4 h. Then,the selective precipitation of REEs with 81.3% REEs recovery is realized by heating up the leaching solution from 25 to 90 ℃ and keeping for4 h. Thereafter, more than 95% phosphoric acid is recovered by H_2 SO_4 and high purity gypsum, more than95% CaSO_4(tested by XRF), is also produced at the same time. Ultimately, a green process that leaches phosphate rock with H_3 PO_4, selectively precipitates REEs from leaching solution by heating up, recovers H_3 PO_4 with H2 SO4 is proposed. Compared with REE recovery in traditional processes, this process owns the merits of simple operation, energy saving and minimum wastes.

关键词： Rare earth elements Phosphate rock Monocalcium phosphate Minimum

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A study of the protein-protein interactions in the phycocyanin monomer from Synechocystis *** 6803 using a bacterial two-hybrid system

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Engineering Microbiology 2022年第2期2卷 37-41页

作者： Simi Shao longsheng zhao Pingyi Li Hainan Su Xiulan Chen Yuzhong Zhang State Key Laboratory of Microbial Technology Marine Biotechnology Research CenterShandong UniversityQingdao 266237China College of Marine Life Sciences Ocean University of ChinaQingdao 266237China Frontiers Science Center for Deep Ocean Multispheres and Earth System Ocean University of ChinaQingdao 266237China Laboratory for Marine Biology and Biotechnology Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China

Investigations into the intramolecular interactions of the native protein in solution are important to understand its structural stability as well as its potential uses in future *** this study,we used a bacterial two-hybrid system to investigate the interaction between the phycocyanin𝛼and𝛽subunits that form the phycocyanin *** amino acid residues responsible for the interaction between the subunits were identified,providing direct experimental evidence for the intramolecular interaction.

关键词： Phycocyanin Monomer Interaction Bacterial two-hybrid system

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基于分层理论的层合板结构声辐射模态传感器设计

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机械工程学报 2014年第3期50卷 116-122页

作者：吴锦武赵龙胜黄凌志南昌航空大学飞行器工程学院南昌330063

在低频时控制振动板结构的声辐射模态幅值是降低结构辐射声功率的一种有效策略。提出一种阵列式压电式传感器的设计方法测量复合材料层合板结构声辐射模态幅值。通过聚偏氟乙烯(Polyvinylidene fluoride,PVDF)传感器阵列输出信号设计加... 详细信息

在低频时控制振动板结构的声辐射模态幅值是降低结构辐射声功率的一种有效策略。提出一种阵列式压电式传感器的设计方法测量复合材料层合板结构声辐射模态幅值。通过聚偏氟乙烯(Polyvinylidene fluoride,PVDF)传感器阵列输出信号设计加权系数,使PVDF传感器阵列输出信号为所需结构声辐射模态幅值。加权系数取决于复合材料层合板结构振动模态表达式。由于复合材料层合板结构复杂动力学特性,通过分层理论结合有限元法得到离散结构模态值,并对有限元离散结构模态进行最小二乘法的曲线拟合,从而得到层合板结构振动模态表达式。数值结果表明该方法计算层合板结构模态以及PVDF声辐射模态传感器设计是可行的。对试验数据进行分析比较。

关键词：层合板声辐射模态分层理论压电传感器

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