Discussion on Pretreatment Method for Extracting Rare Earth Elements from Weathered Crust Elution-deposited Rare Earth Ores

ZHU Yun; GUO Lin; YU Tingting; LU Ran; ZHANG Lei; QU Wenjun; DING Hongrui; MA Shengfeng

doi:10.15898/j.ykcs.202308070130

Rock and Mineral Analysis > 2023 > 42(5): 877-887. > DOI: 10.15898/j.ykcs.202308070130

ZHU Yun，GUO Lin，YU Tingting，et al. Discussion on Pretreatment Method for Extracting Rare Earth Elements from Weathered Crust Elution-deposited Rare Earth Ores[J]. Rock and Mineral Analysis，2023，42（5）：877−887. DOI: 10.15898/j.ykcs.202308070130

Citation:

PDF (736 KB)

Discussion on Pretreatment Method for Extracting Rare Earth Elements from Weathered Crust Elution-deposited Rare Earth Ores

1.
National Research Center for Geoanalysis, Beijing 100037, China
2.
School of Earth and Space Science, Peking University, Beijing 100871, China

More Information

Received Date: August 06, 2023
Revised Date: August 30, 2023
Accepted Date: September 16, 2023
Available Online: November 07, 2023

Abstract

ABSTRACT

BACKGROUND
Weathered crust elution-deposited rare earth ores are the dominant mineral resources in China^[1-5]. The occurrence of rare earth elements (REEs) in weathering crust elution-deposited is very complicated. At present, the “ionic” rare earth extraction process can only use the “exchangeable adsorption state” rare earth elements, that is, the “ionic phase” rare earth elements, and other phase rare earth elements cannot be effectively recycled^[6]. How to effectively dissolve various forms of rare earth elements in ion-adsorbed rare earth ore is very important to improve the utilization rate of rare earth resources.
OBJECTIVES
To compare the extraction efficiency of REEs in weathered crust elution-deposited rare earth ores by different pretreatment methods and discuss the influencing factors.
METHODS
Five pretreatment methods, being open mixed acid digestion (HCl+HNO₃+HF+HClO₄+H₂SO₄), nitric acid digestion with or without hydrogen peroxide, hydrochloric acid digestion with hydrogen peroxide and ammonium sulfate leaching, were used to extract REEs in six rare earth samples from the Nanling area. The content of REEs in samples was determined by ICP-MS.　　For ion-adsorbed rare earth minerals, the open digestion method of five acids can replace the complicated alkali melting method for the determination of REEs in samples under certain conditions. Nitric acid, hydrochloric acid digestion or ammonium sulfate leaching can only dissolve part of REEs in ion-adsorbed rare earth samples.
RESULTS
The amount of REE extracted by different pretreatment methods is quite different. The results of mixed acid digestion (five acids) are the highest; the results of nitric acid with or without hydrogen peroxide digestion, hydrochloric acid and hydrogen peroxide digestion are similar. The amount of REEs dissolved by nitric acid or hydrochloric acid digestion is slightly lower than mixed acid digestion. The amount of REEs dissolved by ammonium sulfate leaching is the lowest. The amount of REEs dissolved by 50% nitric acid, hydrochloric acid and other digestion methods accounts for 75.3%-91.7% of the total phase REEs, and the amount of REEs dissolved by ammonium sulfate leaching (ionic phase rare earth) only accounts for 9.1%-5.5% of the total phase REEs.　　The extraction rate of scandium (Sc) is much lower than that of total REEs in nitric acid and hydrochloric acid digestion, and Sc can not be dissolved by ammonium sulfate leaching. There is no correlation between the extraction rate of cerium (Ce) and other REE, the total extraction rate of light REE or the total extraction rate of REEs.　　The difference of the results by different pretreatments is closely related to the occurrence state of REEs in the samples. Mixed acid digestion can completely destroy the structure of the sample, and all the REEs in the sample can be dissolved. The REEs are differentiated and enriched in weathering crust layers. Some REEs still exist in the form of mineral facies after weathering. The content of REEs in ionic phase is closely related to weathering degree and mineral composition of each layer of weathering crust. Proportion of REEs content in different parts of weathering crust is not the same. Hydrochloric acid or nitric acid can dissolve REEs in the ionic state adsorbed in clay minerals or iron and manganese oxides, as well as REEs in the form of carbonates, phosphates, etc. Some REEs exist stably in silicate mineral lattices that cannot be completely dissolved by nitric or hydrochloric acid. Ammonium sulfate leaching can only dissolve the ionic REEs in the sample, so the digestion result of hydrochloric acid and nitric acid is lower than that of the whole phase REEs, and higher than that of ammonium sulfate leaching.
CONCLUTIONS
The differences and influencing factors of REEs extracted from ion-adsorbed rare earth samples by different pretreatment methods are discussed, which can provide reference for further research on the extraction methods of REEs from elution-deposited rare earth ores. Mixed acid digestion can extract the full phase REEs in the weathered crust eluviated rare earth ore sample, which can be used to evaluate the total amount of REEs in the weathered crust eluviated rare earth ore. Nitric acid digestion, nitric acid and hydrogen peroxide digestion, hydrochloric acid and hydrogen peroxide digestion cannot dissolve REEs in the silicate structure completely. Therefore, this method is suitable for evaluating the content of REEs in the form of ionic states, oxides, carbonates and phosphates in samples. Ammonium sulfate leaching can be used to evaluate the content of ionic phase REEs in weathering crust leaching type rare earth ores.　　The extraction rate of REEs is greatly affected by the chemical characteristics and occurrence state of REEs. Because the ionic radius of Sc³⁺ is obviously smaller than that of other REEs, Sc³⁺ can enter the crystal lattices of many rock-forming minerals in the form of homogeneity, which results in that ammonium sulfate leaching cannot dissolve Sc. Only a small amount of Sc can be dissolved by hydrochloric or nitric acid digestion. The different enrichment-differentiation characteristics of Ce and other REEs also make the extraction rate of Ce by ammonium sulfate leaching inconsistent with other REEs. The REEs with similar ionic radii often have similar extraction efficiency in the same pretreatment.
- weathered crust elution-deposited rare earth ores,
- sample pretreatment,
- rare earth elements (REEs),
- acid digestion,
- ammonium sulfate leaching,
- ICP-MS

FullText(HTML)

References (30)

References

[1]	池汝安, 田军. 风化壳淋积型稀土矿评述[J]. 中国稀土学报, 2007, 51(6): 641−650. doi: 10.3321/j.issn:1000-4343.2007.06.001 Chi R A, Tian J. Review of weathered crust rare earth ore[J]. Journal of the Chinese Rare Earth Society, 2007, 51(6): 641−650. doi: 10.3321/j.issn:1000-4343.2007.06.001
[2]	赵芝, 王登红, 陈郑辉, 等. 南岭离子吸附型稀土矿床成矿规律研究新进展[J]. 地质学报, 2017, 91(12): 2814−2827. doi: 10.3969/j.issn.0001-5717.2017.12.016 Zhao Z, Wang D H, Chen Z H, et al. Progress of research on metallogenic regularity of ion-adsorption type REE deposit in the Nanling Range[J]. Acta Geologica Sinica, 2017, 91(12): 2814−2827. doi: 10.3969/j.issn.0001-5717.2017.12.016
[3]	赵芝, 王登红, 王成辉, 等. 离子吸附型稀土找矿及研究新进展[J]. 地质学报, 2019, 93(6): 1454−1465. doi: 10.3969/j.issn.0001-5717.2019.06.021 Zhao Z, Wang D H, Wang C H, et al. Progress in prospecting and research of ion-adsorption type REE deposits[J]. Acta Geologica Sinica, 2019, 93(6): 1454−1465. doi: 10.3969/j.issn.0001-5717.2019.06.021
[4]	雒恺, 马金龙. 花岗岩风化过程中稀土元素迁移富集机制研究进展[J]. 地球科学进展, 2022, 37(7): 692−708. doi: 10.11867/j.issn.1001-8166.2022.7.dqkxjz202207003 Luo K, Ma J L. Recent advances in migration and enrichment of rare earth elements during chemical weathering of granite[J]. Advances in Earth Science, 2022, 37(7): 692−708. doi: 10.11867/j.issn.1001-8166.2022.7.dqkxjz202207003
[5]	池汝安, 张臻悦, 余霞军, 等. 风化淋积型稀土矿研究进展[J]. 中国矿业大学学报, 2022, 51(6): 1178−1192. Chi R A, Zhang Z Y, Yu X J, et al. Research process of weathered crust elution-deposited rare earth ore[J]. Journal of China University of Mining & Technology, 2022, 51(6): 1178−1192.
[6]	丁嘉榆. 离子型稀土矿开发的历史回顾——纪念赣州有色冶金研究所建所60周年[J]. 有色金属科学与工程, 2012, 3(4): 14−19. Ding J Y. Historical review of the ionic rare earth mining: In honor of the 60 anniversary of GNMRI[J]. Nonferrous Metal Science and Engineering, 2012, 3(4): 14−19.
[7]	Yang M J, Liang X L, Ma L Y, et al. Adsorption of REEs on kaolinite and halloysite: A link to the REE distribution on clays in the weathering crust of granite[J]. Chemical Geology, 2019, 525: 210−217. doi: 10.1016/j.chemgeo.2019.07.024
[8]	王臻, 肖仪武, 冯凯. 离子吸附型稀土矿成矿特点及元素赋存形式[J]. 有色金属(选矿部分), 2021(6): 43−51. Wang Z, Xiao Y W, Feng K. Metallogenic characteristics and occurrence of REE in ion adsorption type rare earth deposits[J]. Nonferrous Metal (Mineral Processing Section), 2021(6): 43−51.
[9]	Mukai H, Kon Y, Sanematsu K, et al. Microscopic analyses of weathered granite in ion-absorption rare earth deposit of Jianxi Province, China[J]. Scientific Reports, 2020, 10: 2045−2322. doi: 10.1038/s41598-020-58985-6
[10]	佘海东, 范宏瑞, 胡芳芳, 等. 稀土元素在热液中的迁移与沉淀[J]. 岩石学报, 2018, 34(12): 3567−3581. She H D, Fan H R, Hu F F, et al. Migration and precipitation of rare earth elements in the hydrothermal fluids[J]. Acta Petrologica Sinica, 2018, 34(12): 3567−3581.
[11]	吴石头, 王亚平, 孙德忠, 等. 电感耦合等离子体发射光谱法测定稀土矿石中15种稀土元素——四种前处理方法的比较[J]. 岩矿测试, 2014, 33(1): 12−16. doi: 10.3969/j.issn.0254-5357.2014.01.003 Wu S T, Wang Y P, Sun D Z, et al. Determination of 15 rare earth elements in rare earth ores by inductively coupled plasma-atomic emission spectrometry: A comparison of four different pretreatment methods[J]. Rock and Mineral Analysis, 2014, 33(1): 12−16. doi: 10.3969/j.issn.0254-5357.2014.01.003
[12]	宋旭东, 樊小伟, 陈文, 等. 电感耦合等离子体质谱法测定离子吸附型稀土矿中全相稀土总量[J]. 冶金分析, 2018, 38(6): 19−24. doi: 10.13228/j.boyuan.issn1000-7571.010305 Song X D, Fan X W, Chen W, et al. Determination of total-phase rare earth content in ion-adsorption rare earth ore by inductively coupled plasma mass spectrometry[J]. Metallurgical Analysis, 2018, 38(6): 19−24. doi: 10.13228/j.boyuan.issn1000-7571.010305
[13]	张磊, 周伟, 朱云, 等. 硫酸铵溶液淋滤-电感耦合等离子体质谱测定离子相稀土分量的方法优化[J]. 岩矿测试, 2018, 37(5): 518−525. doi: 10.15898/j.cnki.11-2131/td.201712110192 Zhang L, Zhou W, Zhu Y, et al. An optimized method for determination of ionic phase rare earth elements by ICP-MS using ammonium sulfate leaching[J]. Rock and Mineral Analysis, 2018, 37(5): 518−525. doi: 10.15898/j.cnki.11-2131/td.201712110192
[14]	池汝安, 田君, 罗仙平, 等. 风化壳淋积型稀土矿的基础研究[J]. 有色金属科学与工程, 2012, 3(4): 1−13. doi: 10.13264/j.cnki.ysjskx.2012.04.010 Chi R A, Tian J, Luo X P, et al. The basic research on the weathered crust elution-deposited rare earth ores[J]. Nonferrous Metals Science and Engineering, 2012, 3(4): 1−13. doi: 10.13264/j.cnki.ysjskx.2012.04.010
[15]	施意华, 邱丽, 唐碧玉, 等. 电感耦合等离子体质谱法测定离子型稀土矿中离子相稀土总量及分量[J]. 冶金分析, 2014, 34(9): 14−19. doi: 10.13228/j.issn.1000-7571.2014.09.003 Shi Y H, Qiu L, Tang B Y, et al. Determination of total ionic-phase rare earth and component in ion-adsorption rare earth ore by inductively coupled plasma mass spectrometry[J]. Metallurgical Analysis, 2014, 34(9): 14−19. doi: 10.13228/j.issn.1000-7571.2014.09.003
[16]	刘艳珠, 丁正雄, 孔维长, 等. 离子吸附型稀土浸取试剂和富集回收技术的演变——从抑杂浸取到强化浸取及分阶段的选择——强化浸取[J]. 中国稀土学报, 2023, 41(3): 610−622. Liu Y Z, Ding Z X, Kong W Z, et al. Evolution of leaching reagents and enrichment recovery technology of ion adsorption rare earths: Leaching strategy from impurity suppression to enhancing and selection-enhancing in stages[J]. Journal of the Chinese Society of Rare Earths, 2023, 41(3): 610−622.
[17]	白金峰, 张勤, 孙晓玲, 等, 高分辨电感耦合等离子体质谱法测定地球化学样品中钪钇和稀土元素[J]. 岩矿测试, 2011, 30(1): 17-22. Bai J F, Zhang Q, Sun X L, et al. Determination of Sc, Y and rare earth elements in geochemical samples by high resolution inductively coupled plasma-mass spectrometry[J]. Rock and Mineral Analysis, 2011, 30(1): 17-22.
[18]	刘贵磊, 许俊玉, 温宏利, 等. 动态反应池-电感耦合等离子体质谱法精确测定配分差异显著的重稀土元素[J]. 桂林理工大学学报, 2016, 36(1): 176−183. doi: 10.3969/j.issn.1674-9057.2016.01.024 Liu G L, Xu J Y, Wen H L, et al. Determination of heavy rare earth elements of special rare earth ores by inductively coupled plasma mass spectrometry with a dynamic reaction cell[J]. Journal of Guilin University of Technology, 2016, 36(1): 176−183. doi: 10.3969/j.issn.1674-9057.2016.01.024
[19]	时晓露, 凤海元. 电感耦合等离子体质谱法测定离子吸附型稀土矿中16种离子吸附型稀土元素的含量[J]. 理化检验(化学分册), 2016, 52(10): 1230−1233. Shi X L, Feng H Y. ICP-MS determination of 16 ionic adsorptive rare earth elements in ionic rare earth ores[J]. Physical Testing and Chemical Analysis (Part B: Chemical Analysis), 2016, 52(10): 1230−1233.
[20]	张磊, 李迎春, 屈文俊, 等. 离子吸附型稀土监控样定值研究[J]. 岩矿测试, 2020, 39(6): 878−885. doi: 10.15898/j.cnki.11-2131/td.202004230058 Zhang L, Li Y C, Qu W J, et al. Preparation of ion-adsorption type REE monitoring samples[J]. Rock and Mineral Analysis, 2020, 39(6): 878−885. doi: 10.15898/j.cnki.11-2131/td.202004230058
[21]	苏春风. 电感耦合等离子体质谱(ICP-MS)法测定稀土矿中16种稀土元素含量[J]. 中国无机分析化学, 2020, 10(6): 28−32. doi: 10.3969/j.issn.2095-1035.2020.06.007 Su C F. Determination of 16 rare elements in rare earth ores by inductively coupled plasma mass spectrometry[J]. Chinese Journal of Inorganic Analytical Chemistry, 2020, 10(6): 28−32. doi: 10.3969/j.issn.2095-1035.2020.06.007
[22]	罗武平, 李光来, 李成祥, 等. 江西相山下家岭稀土矿物风化壳剖面地球化学特征[J]. 矿物学报, 2019, 39(3): 237−246. Luo W P, Li G L, Li C X, et al. Geochemical characteristics of the weathered crust profile in the Xiajialing REE deposit of the Xiangshan area, Jiangxi Province, China[J]. Acta Mineralogica Sinica, 2019, 39(3): 237−246.
[23]	黄健, 谭伟, 梁晓亮, 等. 富稀土副矿物的风化特征及其对稀土成矿过程的影响——以广东仁居离子吸附型稀土矿床为例[J]. 地球化学, 2022, 51(6): 684-695. Huang J, Tan W, Liang X L, et al. Weathering characters of REE-bearing accessory minerals and their effects on REE mineralization in Renju regolith-hosted REE deposits in Guangdong Province[J]. 地球化学, 2022, 51(6): 684-695.
[24]	梁晓亮, 谭伟, 马灵涯, 等. 离子吸附型稀土矿床形成的矿物表/界面反应机制[J]. 地学前缘, 2022, 29(1): 29−41. Liang X L, Tan W, Ma L Y, et al. Mineral surface reaction constraints on the formation of ion-adsorption rare earth element deposits[J]. Earth Science Frontiers, 2022, 29(1): 29−41.
[25]	伍普球, 周靖文, 黄健, 等. 离子吸附型稀土矿床中稀土的富集-分异特征: 铁氧化物-黏土矿物复合体的约束[J]. 地球化学, 2022, 51(3): 271−282. Wu P Q, Zhou J W, Huang J, et al. Enrichment and fractionation of rare earth elements in ion-adsorption rare earth elements deposits: Constraints of iron oxide-clay mineral composites[J]. Geochimica, 2022, 51(3): 271−282.
[26]	范晨子, 张誉, 陈郑辉, 等. 江西赣南风化淋滤型稀土矿床中粘土矿物研究[J]. 岩石矿物学杂志, 2015, 34(5): 803−810. Fan C Z, Zhang Y, Chen Z H, et al. The study of clay minerals from weathered crust rare earth ores in Southern Jiangxi Province[J]. Acta Petrologica et Mineralogica, 2015, 34(5): 803−810.
[27]	王长兵, 倪光清, 瞿亮, 等. 花岗岩风化壳中Ce地球化学特征及其找矿意义——以滇西岔河离子吸附型稀土矿床为例[J]. 矿床地质, 2021, 10(5): 1013−1028. doi: 10.16111/j.0258-7106.2021.05.008 Wang C B, Ni G Q, Qu L, et al. Ce geochemical characteristics of granite weathering crust and its prospecting significance: A case study of Chahe ion adsorption rare earth deposit in Western Yunnan[J]. Mineral Desposits, 2021, 10(5): 1013−1028. doi: 10.16111/j.0258-7106.2021.05.008
[28]	Williams-Jones A E, Vasyukova O V. The economic geology of scandium, the runt of the rare earth element litter[J]. Economic Geology, 2018, 113(4): 973−988. doi: 10.5382/econgeo.2018.4579
[29]	陶旭云, 王佳新, 孙嘉, 等. 钪矿床类型与成矿机制[J]. 矿床地质, 2019, 38(5): 1023−1038. Tao X Y, Wang J X, Sun J, et al. Main types and metallogenic mechanism of scandium deposits[J]. Mineral Deposits, 2019, 38(5): 1023−1038.
[30]	Chakhmouradian A R, Wall F. Rare earth elements: Minerals, mines, magnets (and more)[J]. Elements, 2012, 8(5): 333−340. doi: 10.2113/gselements.8.5.333