【作者】 周杰；

【导师】 廖伍平；

【作者基本信息】 中国科学技术大学 ， 化学， 2025， 博士

【摘要】 本文针对南方离子型稀土矿的几个分离点——低浓度稀土回收、稀土中微量放射性钍的深度去除、高丰度钇的分离提纯和高纯重稀土的高效制备,设计合成和筛选了四种多孔材料PB2MP、PCA、G518和HEHAEP/SiO₂-P,系统研究了其对目标金属离子的吸附性能和吸附机理,提出了四种分离流程。全文遵循“材料合成/表征-性能评价-机理分析-应用验证”的研究框架,主要研究结果如下:（1）研究了聚双（2-（甲基丙烯酰氧基）乙基）磷酸酯（PB2MP）树脂从南方离子型稀土矿中选择性回收低浓度稀土。在pH为2.0时,PB2MP-1树脂对La/Al、Gd/Al、Y/Al和Lu/Al的分离系数（SF）分别为1.57、7.64、8.21和18.94,且不吸附Ca（II）和Mg（II）。PB2MP-0、PB2MP-1和PB2MP-2树脂对Yb（III）的最大吸附容量分别为211.5、167.8和85.3 mg/g。3.0 mol/L HCl可完全解吸PB2MP-1树脂中负载的Yb（III）,且在五次吸附-解吸循环中Yb（III）的吸附率和解吸率均保持稳定。稀土离子通过阳离子交换和中性络合机理与P-OH及P=O官能团中的氧原子发生配位作用。单次吸附-解吸能将离子型稀土矿浸出液中的稀土占总金属离子的含量从21.88 wt%提升至86.95 wt%。（2）合成了大空间位阻的聚肉桂酸（PCA）树脂用于从稀土中深度去除微量放射性钍。PCA树脂对钍离子具有超高选择性和亲和力,在Lu/Th摩尔比为350的二元溶液中,SF_Th/Lu高达4158,对Th（IV）的最大吸附容量为405.2 mg/g。pH=2.0 H₂SO₄可以解吸负载钍的PCA树脂中>98%的钍。PCA树脂的循环和再生性能较好,经pH=2 HCl溶液浸泡10天依然稳定。吸附机理为-COOH基团的H⁺与Th（IV）发生阳离子交换,并通过羧酸的氧原子与钍离子发生双齿螯合配位。PCA树脂将模拟放射性废水中的钍浓度从5.5 mg/L降至0.005 mg/L,高纯度Lu Cl₃溶液中的钍浓度从0.56 mg/L降至0.007 mg/L,稀土几乎均无损失。（3）研究了亚氨基二乙酸（G518）树脂从镧系元素中选择性分离提纯钇。在pH为4.0时,La/Y、Eu/Y、Ho/Y、Er/Y和Lu/Y的分离系数分别为1.18、2.36、2.19、2.46和3.38。G518对La（III）、Gd（III）、Ho（III）、Y（III）、Er（III）和Lu（III）的最大吸附容量分别为165.0、192.6、196.3、110.0、197.2和214.9 mg/g。0.5 mol/L HCl可完全解吸负载的稀土离子,在五次吸附-解吸循环中Y（III）的吸附容量保持稳定。吸附机理是Y（III）与-COONa基团中钠离子发生阳离子交换,通过羧酸根的氧原子和氨基的氮原子与钇离子发生三齿螯合配位。动态柱实验将钇的相对纯度从99.98%提升至>99.9999%,绝对纯度从98.67%提升至99.993%。（4）制备了β-氨基膦酸/硅基聚合物（HEHAEP/SiO₂-P）树脂用于分离提纯重稀土。在pH为2.0时,Er/Ho、Tm/Er、Yb/Tm和Lu/Yb的分离系数分别为2.35、3.62、3.14和1.23,高于其它浸渍树脂。HEHAEP/SiO₂-P对Ho（III）、Er（III）、Tm（III）、Yb（III）和Lu（III）的最大吸附容量分别为33.5、34.6、37.0、38.3和43.2 mg/g。4.0 mol/L HNO₃可解吸负载树脂的重稀土离子。吸附机理为P-OH和P=O基团的氧原子与重稀土离子配位,遵循阳离子交换机制,同时伴有中性络合。动态柱实验不仅能分离轻、中和重稀土,而且能将Tm₂O₃纯度由99.96%提升至99.997%。更多还原

【Abstract】 Addressing the critical challenges in southern ionic rare earth ore processing,i.e.,the recovery of low concentration of rare earths,the deep removal of trace radioactive thorium from rare earths,separation and purification of high abundance yttrium and the efficient preparation of heavy rare earths.We developed four porous polymer materials,PB2MP,PCA,G518,and HEHAEP/SiO₂-P.Their adsorption behaviors and mechanisms for target metal ions were systematically investigated,and four separation processes were established.The whole paper follows the research framework of“material synthesis/characterization-performance evaluation-mechanism analysis-application verification”.The principal findings are summarized as follows:（1）Polybis（2-（methacryloyloxy）ethyl）phosphate（PB2MP）resins were synthesized for selective recovery of low concentrations of rare earths from southern ionic rare earth ores.At pH 2.0,the separation factors（SF）of PB2MP-1 resin for La/Al,Gd/Al,Y/Al and Lu/Al were 1.57,7.64,8.21 and 18.94,respectively,and adsorbed no Ca²⁺and Mg²⁺.The maximum adsorption capacity of PB2MP-0,PB2MP-1 and PB2MP-2 resins for Yb（III）was 211.5,167.8 and 85.3 mg/g,respectively.Yb（III）could be completely desorbed from the loaded PB2MP-1 resin using 3.0 mol/L HCl,and the adsorption and desorption rates of Yb（III）remain steady in five adsorption-desorption cycles.The rare earth ions coordinate with oxygen atoms in the P-OH and P=O functional groups by cation exchange and neutral complexation mechanisms.A single adsorption-desorption enhanced the rare earth content of 21.88 wt%to 86.95 wt%in the leach solution of ionic rare earth ores.（2）Polycinnamic acid（PCA）resin with large steric hindrance was synthesized for deep removal of trace radioactive thorium from rare earths.The PCA resin offers desirable selectivity and affinity towards thorium other than rare earth ions,reaching a high SF_Th/Lu of 4158 at a Lu/Th molar ratio of 350 and a maximum adsorption capacity of 405.2 mg/g for Th（IV）.Desorption of thorium from the loaded resin ions was effectively accomplished using H₂SO₄ solution at pH<2.The PCA resin exhibited excellent cycling and regeneration performance,remaining stable in pH=2 HCl for 10days of immersion.The adsorption mechanism involves cation exchange between Th（IV）and H⁺of the-COOH group and the two oxygen atoms of-COOH are bidentate chelating coordination with the thorium ion.The PCA resin reduced the thorium concentration from 5.5 mg/L to 0.005 mg/L in simulated radioactive wastewater and from 0.56 mg/L to 0.007 mg/L in high-purity Lu Cl₃ solution,with no measurable loss of rare earths.（3）The selective separation and purification of yttrium from lanthanides by iminodiacetic acid（G518）resin was investigated.At pH=4.0,the separation factors for La/Y,Eu/Y,Ho/Y,Er/Y,and Lu/Y were 1.18,2.36,2.19,2.46,and 3.38,respectively.The maximum adsorption capacities of G518 for La（III）,Gd（III）,Ho（III）,Y（III）,Er（III）and Lu（III）were 165.0,192.6,196.3,110.0,197.2 and 214.9 mg/g,respectively.Complete desorption of rare earth ions was achieved from the loaded resin using 0.5mol/L HCl,and the adsorption capacity of Y（III）remained steady in five adsorption-desorption experiments.The adsorption mechanism involves the cation exchange of Y（III）with Na⁺of the-COONa group,and the tridentate chelating coordination with Y（III）by the two oxygen atoms of carboxylate and the nitrogen atom of the amino group.Dynamic column experiments improved the relative purity of yttrium from 99.98%to>99.9999,and the absolute purity from 98.67%to 99.993%.（4）Aβ-aminophosphonic acid/silica-based polymer（HEHAEP/SiO₂-P）resin was prepared for the separation and purification of heavy rare earths.At pH=2.0,the separation factors for Er/Ho,Tm/Er,Yb/Tm and Lu/Yb were 2.35,3.62,3.14 and 1.23,respectively,surpassing those of some other reported impregnating resins.The maximum adsorption capacity of HEHAEP/SiO₂-P for Ho（III）,Er（III）,Tm（III）,Yb（III）and Lu（III）were 33.5,34.6,37.0,38.3 and 43.2 mg/g,respectively.Complete desorption of the adsorbed HREs was achieved using 4.0 mol/L HNO₃.The adsorption mechanism involves the coordination of oxygen atoms of P-OH and P=O groups with heavy rare earth ions,which follow a cation exchange mechanism accompanied by neutral complexation.Dynamic column experiments not only separated light,medium and heavy rare earths,the purity of commercial Tm₂O₃ was improved from 99.96%to99.997%.更多还原