【作者】 裴亮；

【导师】 姚秉华；

【作者基本信息】 西安理工大学 ， 环境工程， 2010， 博士

【摘要】 本文涉及一种稀土金属的迁移与分离回收技术,主要研究了以多孔高分子聚合物膜为支撑体,有机磷酸为流动载体,煤油为膜溶剂,煤油和流动载体的混合溶液作为膜溶液,膜溶液和HCl溶液组成分散相的分散支撑液膜(DSLM)中几种稀土金属的迁移和分离回收行为,通过传质过程分析,建立相应的数学模型,取得以下研究结果：1、采用以2-乙基己基膦酸-单-2-乙基己基酯(PC-88A)为流动载体的DSLM体系对La(Ⅲ)、Ce(Ⅳ)、Tb(Ⅲ)、Eu(Ⅲ)、Dy(Ⅲ)和Tm(Ⅲ)的迁移行为进行了研究.考察了料液相pH、金属离子初始浓度、分散相中HCl浓度、膜溶液与HCl溶液体积比、不同解析剂及不同载体浓度对La(Ⅲ).Ce(IV).Tb(Ⅲ).Eu(Ⅲ).Dy(Ⅲ)和Tm(Ⅲ)迁移的影响,得出了La(Ⅲ).Ce(IV).Tb(Ⅲ).Eu(Ⅲ).Dy(Ⅲ)和Tm(Ⅲ)最优迁移条件分别为：分散相中HCl溶液浓度都为4.00 mol/L;膜溶液与HCl溶液体积比分别为30：30、40：20、30：30、30：30、40：20和40：20；载体浓度分别控制在0.160 mol/L、0.160 mol/L、0.100 mol/L、0.160 mol/L、0.100 mol/L和0.160 mol/L;料液相pH分别为4.00、1.00、5.20、4.20、5.00和5.10；在最优条件下,料液相中La(Ⅲ).Ce(Ⅳ)、Tb(Ⅲ)、Eu(Ⅲ).Dy(Ⅲ)和Tm(Ⅲ)的初始浓度分别为8.00×10-5 mol/L.7.O0×10-5 mol/L.1.00×10-4mol/L.8.00×10-5 mol/L.8.00×10-5 mol/L和1.00×10-4mol/L时,分别迁移125 min.75 min、95 min、130 min.95 min和155 min,迁移率分别达到93.9%、96.3%、95.2%、95.3%、96.2%和92.2%。2、采用以二-(2-乙基己基)磷酸(D2EHPA)为流动载体的DSLM体系对La(Ⅲ).Ce(Ⅳ). Tb(Ⅲ).Eu(Ⅲ).Dy(Ⅲ)和Tm(Ⅲ)的迁移行为进行了研究。考察了料液相pH、金属离子初始浓度、分散相中HCl浓度、膜溶液与HCl溶液体积比、不同解析剂及不同载体浓度对La(Ⅲ).Ce(Ⅳ).Tb(Ⅲ).Eu(Ⅲ).Dy(III)和Tm(Ⅲ)迁移的影响,得出了La(Ⅲ).Ce(IV). Tb(Ⅲ).Eu(Ⅲ).Dy(Ⅲ)和Tm(Ⅲ)最优迁移条件分别为：分散相中HCl溶液浓度都为4.00mol/L;膜溶液与HCl溶液体积比分别为20：40、30：30、30：30、30：30、20：40和40：20；载体浓度都控制在0.160 mol/L;料液相pH分别为5.00、0.50、4.50、5.00、4.50和5.00；在最优条件下,料液相中La(Ⅲ)、Ce(Ⅳ)、Tb(Ⅲ)、Eu(Ⅲ)和Tm(Ⅲ)的初始浓度均为1.OOx10-4 mol/L时,迁移35 min, La(Ⅲ)、Tb(Ⅲ)、Eu(III)、Dy(Ⅲ)和Tm(Ⅲ)迁移率分别达到94.8%、99.1%、93.7%、98.2%和99.2%,Ce(Ⅳ)迁移30 min,迁移率达到78.3%。稀土金属迁移过程中,最适合的解析剂是HCl; Eu(Ⅲ)的迁移率随离子强度的增加而增加,其它稀土金属的迁移率受离子强度影响不明显。3、PC-88A和D2EHPA混合作为载体时,研究了DSLM体系中Tb(Ⅲ)、Eu(Ⅲ)和Dy(Ⅲ)的迁移行为。考察了分散相中HCl浓度、膜溶液与HCl溶液体积比、料液相pH、金属离子初始浓度、不同解析剂以及混合载体浓度与比例对Tb(Ⅲ)、Eu(Ⅲ)和Dy(Ⅲ)迁移的影响,得出了Tb(Ⅲ)、Eu(Ⅲ)和Dy(Ⅲ)的最佳迁移条件为：分散相中HCl溶液浓度均为4.00mol/L;膜溶液与HCl溶液体积比分别为20：40、40：20和40：20；膜溶液中PC-88A与D2EHPA浓度均为8.00x10-2 mol/L;料液相pH分别为3.80、4.80和3.80；在最优条件下,料液相中Tb(Ⅲ)、Eu(Ⅲ)和Dy(Ⅲ)的初始浓度都为1.OO×10-4 mol/L时,30 min,迁移率分别达到95.4%、94.6%和97.0%。4、在对单个稀土金属进行DSLM迁移研究的基础上,对混合稀土金属进行了DSLM分离研究,取得了以下结果：(1)PC-88A为载体时,在La(Ⅲ)、Ce(Ⅳ)、Tb(Ⅲ)、Eu(III)、Dy(Ⅲ)、Tm(Ⅲ)混合稀土金属的DSLM分离体系中选择液相酸度为0.50 mol/L、分散相中HCl浓度为4.00 mol/L、膜溶液与HCl溶液体积比为30：30、载体PC-88A浓度为0.160 mol/L时,在此条件下研究各稀土金属在DSLM中的分离行为,当各元素浓度均为1.00×10-4 mol/L时,Ce(Ⅳ)在120min时,可以与其它稀土金属分离。当调节料液相pH为2.80时,300 min时,Tb(Ⅲ)、Eu(Ⅲ)、Dy(Ⅲ)三种元素与La(Ⅲ)的分离因子分别为3.95、4.87和6.12；与Tm(Ⅲ)的分离因子分别为12.8、15.8和19.8。(2) D2EHPA为载体时,在La(Ⅲ)、Tb(III)、Eu(Ⅲ)、Dy(Ⅲ)、Tm(Ⅲ)混合稀土金属的DSLM分离体系中选择料液相pH为2.80、分散相中HCl浓度为4.00 mol/L、膜溶液与HCl溶液体积比为30:30、D2EHPA浓度为0.160 mol/L时,在此条件下研究各稀土金属在DSLM中的分离行为,当各金属离子浓度均为1.OOx10-4 mol/L时,80 min时,Tb(Ⅲ)、Eu(Ⅲ)、Dy(Ⅲ)三种元素与La(Ⅲ)的分离因子分别为9.24、4.81和1.80；与Tm(Ⅲ)的分离因子分别为64.4、33.5和12.6。Tb(Ⅲ)和Eu(Ⅲ)在此条件下可以很好的与La(Ⅲ)、Dy(Ⅲ)、Tm(Ⅲ)分离。调节料液相pH为2.00时,160 min, Dy(Ⅲ)与La(Ⅲ)的分离因子为23.3；与Tm(Ⅲ)的分离因子为102.9。Dy(Ⅲ)在此条件下可以很好的与La(Ⅲ)与Tm(Ⅲ)分离。La(Ⅲ)和Tm(Ⅲ)的混合溶液,调节料液相pH为3.00,250 min, La(III)与Tm(Ⅲ)的分离因子为19.1。La(Ⅲ)在此条件下可以很好的与Tm(Ⅲ)分离。(3)采用混合载体时,在Tb(III)、Eu(Ⅲ)、Dy(Ⅲ)混合稀土金属的DSLM分离体系中选择料液相pH为2.60、分散相中HCl浓度为4.00 mol/L、膜溶液与HCl溶液体积比为30：30、混合载体中PC-88A和D2EHPA浓度均为8.00×10-2 mol/L时,在此条件下研究混合稀土金属在DSLM中的分离行为,当各稀土金属初始浓度均为1.00×10-4 mol/L时,80min时,Tb(Ⅲ)、Dy(Ⅲ)与Eu(Ⅲ)的分离因子分别为24.2和10.7；Tb(Ⅲ)与Dy(Ⅲ)的分离因子为2.26。Tb(Ⅲ)和Dy(Ⅲ)在此条件下可以很好的与Eu(Ⅲ)分离。调节料液相pH为2.00时,80 min时,Eu(Ⅲ)、Dy(Ⅲ)与Tb(Ⅲ)的分离因子分别为28.9和19.1。Eu(Ⅲ)、Dy(Ⅲ)在此条件下可以与Tb(Ⅲ)分离。5、通过传质分析,证明料液相和分散相中的氢离子是稀土金属通过DSLM迁移的驱动力：迁移实验表明稀土金属在DSLM中的迁移行为宏观上具有连串反应的动力学特征,推导出稀土金属通过DSLM迁移的速率方程、Rf、Rm和Rs与准一级表观速率常数k1和k2的关系及稀土金属离子迁移的通量方程,获得稀土金属通过DSLM迁移动力学参数k1、k2、tmax、Rmmax、Jfmax及Jsmax。通过膜传质过程机理的探索,建立了稀土金属在DSLM中的传质动力学方程,计算出稀土金属通过DSLM迁移动力学参数Af,△m、df和Dm,得到稀土金属的渗透系数方程,通过实验验证了方程与实验结果较为一致。更多还原

【Abstract】 The transport and separation for recovery of some kinds of rare earths through a dispersion supported liquid membrane (DSLM) consisting of polyvinylidene fluoride membrane (PVDF) as the liquid membrane support, dispersion solution including HCl solution as the stripping solution and organophosphates carrier in kerosene as the membrane solution, has been studied. The mathematical model of metal ions transport in liquid membrane systems was established by the analysis of mass transfer. The results are summarized as follows:1. The transport of La(Ⅲ), Ce(IV), Tb(III), Eu(Ⅲ), Dy(III) and Tm(Ⅲ) through a DSLM system with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) as the carrier was studied. Effects of volume ratio of membrane solution and HCl solution, HCl concentration in the dispersion phase, pH in the feed phase, initial concentrations of these rare earths, concentration of PC-88A and different stripping agents on transport of these rare earths have been studied respectively. As a result, the optimum transport conditons of La(III), Ce(Ⅳ), Tb(III), Eu(III), Dy(III) and Tm(III) were obtained as that volume ratio of membrane solution and HCl solution 30:30,40:20,30:30,30:30,40:20 and 40:20 in the dispersion phase respectively, concentration of HCl solution 4.0 mol/L in the dispersion phase, pH value in the feed phase 4.00,1.00,5.20,4.20,5.00 and 5.10 respectively, concentration of PC-88A 0.160mol/L,0.160 mol/L,0.100 mol/L,0.160 mol/L,0.100 mol/L and 0.160 mol/L in the membrane solution respectively. Under the optimum conditions, when initial concentration of La(Ⅲ), Ce(IV), Tb(III), Eu(III), Dy(III) and Tm(III) were 8.00×10-5mol/L,7.00x10-5 mol/L, 1.O0×10-4 mol/L,8.00x10-5mol/L,8.00×10-5 mol/L and 1.OOx10-4mol/L respectively, during the transport time of 125 min,75 min,95 min,130 min,95 min and 155 min the transport percentages of these rare earths are up to 93.9%,96.3%,95.2%,95.3%,96.2% and 92.2% respectively.2. The transport of La(Ⅲ), Ce(IV), Tb(Ⅲ), Eu(Ⅲ), Dy(Ⅲ) and Tm(Ⅲ) through a DSLM system with Di(2-ethylhexyl)phosphoric acid (D2EHPA) as the carrier was studied. Effects of volume ratio of membrane solution and HCl solution, HCl concentration in the dispersion phase, pH in the feed phase, initial concentrations of these rare earths, concentration of D2EHPA and different strip agents on transport of these rare earths have been studied respectively. As a result, the optimum transport conditons of La(Ⅲ), Ce(IV), Tb(Ⅲ), Eu(Ⅲ), Dy(Ⅲ) and Tm(Ⅲ) were obtained as that volume ratio of membrane solution and HCl solution 20:40,30:30,30:30, 30:30,20:40 and 40:20 in the dispersion phase respectively, concentration of HCl solution 4.00 mol/L in the dispersion phase, pH value in the feed phase 5.00,0.500,4.50,5.00,4.50 and 5.00 respectively, concentration of D2EHPA 0.160 mol/L,0.160 mol/L,0.100 mol/L,0.160 mol/L, 0.100 mol/L and 0.160 mol/L in the membrane solution respectively. Under the optimum conditions, when initial concentration of La(III), Tb(III), Eu(III), Dy(Ⅲ) and Tm(III) were all 1.00x10-4 mol/L, during the transport time of 35 min the transport percentages of these rare earths are up to 94.8%,99.1%,93.7%,98.2% and 99.2%, respectively, and the transport percentages of Ce(IV) is 78.3%.3. The transport of Tb(III), Eu(Ⅲ) and Dy(III) through a DSLM system with PC-88A and D2EHPA as the mixed carrier was studied. Effects of volume ratio of membrane solution and HCl, HCl concentration in the dispersion phase, pH in the feed phase, initial concentrations of these rare earths, concentration and ratio of mixed carrier and different stripping agents on transport of these rare earths have been studied respectively. As a result, the optimum transport conditons of Tb(Ⅲ), Eu(Ⅲ) and Dy(Ⅲ) were obtained as that volume ratio of membrane solution and HCl solution 20:40,40:20 and 40:20 in the dispersion phase respectively, concentration of HCl solution 4.00 mol/L in the dispersion phase, pH value in the feed phase 3.80,4.80 and 3.80 respectively, concentration of PC-88A 8.00×10-2 mol/L and D2EHPA 8.00×10-2 mol/L in the membrane solution respectively. Under the optimum conditions, when initial concentration of Tb(Ⅲ), Eu(Ⅲ) and Dy(III) were all 1.OO×1O-4 mol/L, during the transport time of 30 min the transport percentages of these rare earths are up to 95.4%,94.6% and 97.0%.4. According to the transport studies of every rare earths metal in DSLM system, separations of mixed rare earths were studied in DSLM. The results are sumrnarized as follows:(1) DSLM separation system with PC-88A as the carrier:Ce(IV) can be separated from other rare earths in 120 min with PC-88A as the carrier, when initial concentration of La(III), Ce(IV), Tb(Ⅲ), Eu(Ⅲ), Dy(III) and Tm(III) were all 1.00×10-4mol/L, acidity in the feed phase was 0.500 mol/L, volume ratio of membrane solution and HCl solution 30:30, concentration of HCl solution 4.00 mol/L in the dispersion phase, and concentration of PC-88A was 0.160 mol/L in the membrane solution. Then pH in the feed phase was adjusted to 2.80, in 300 min the separation factors of Tb(Ⅲ), Eu(Ⅲ) and Dy(Ⅲ) separated from La(Ⅲ) were 3.95,4.80 and 6.12 respectively. However, Tb(III), Eu(Ⅲ) and Dy(Ⅲ) separated from Tm(III) were 12.8,15.8 and 19.8 respectively.(2) DSLM separation system with D2EHPA as the carrier:In 80 min the separation factors of Tb(Ⅲ), Eu(III) and Dy(Ⅲ) separated from La(Ⅲ) were 9.24,4.81 and 1.80 respectively with D2EHPA as the carrier, when initial concentration of La(Ⅲ), Ce(IV), Tb(Ⅲ), Eu(Ⅲ), Dy(Ⅲ) and Tm(Ⅲ) were all 1.OO＋10-4 mol/L, pH in the feed phase was 2.80, volume ratio of membrane solution and HCl solution 30:30, concentration of HCl solution 4.00 mol/L in the dispersion phase, and concentration of D2EHPA was 0.160 mol/L in the membrane solution. However, Tb(Ⅲ), Eu(Ⅲ) and Dy(Ⅲ) separated from Tm(Ⅲ) were 64.4,33.5 and 12.6 respectively, so Tb(Ⅲ) and Eu(Ⅲ) can be separated from La(Ⅲ), Dy(III) and Tm(Ⅲ). When pH in the feed phase was adjusted to 2.00, in 160 min the separation factors of Dy(Ⅲ) separated from La(Ⅲ) and Tm(III) were 23.3 and 102.9 respectively, so Dy(Ⅲ) can be separated from La(Ⅲ) and Tm(Ⅲ). When pH in the feed phase was adjusted to 3.00, in mixed solution with La(III) and Tm(Ⅲ), in 250 min the separation factors of La(Ⅲ) separated from Tm(Ⅲ) was 19.1, so La(III) can be separated from Tm(III).(3) DSLM separation system with PC-88A and D2EHPA as the mixed carrier:In 80 min the separation factors of Tb(III) and Dy(Ⅲ) separated from Eu(Ⅲ) were 24.2 and 10.7 respectively with PC-88A and D2EHPA as the mixed carrier, when initial concentration of Tb(Ⅲ), Eu(Ⅲ) and Dy(III) were all 1.OOxlO-4mol/L, pH in the feed phase was 2.60, volume ratio of membrane solution and HCl solution 30:30, concentration of HCl solution 4.00 mol/L in the dispersion phase, and concentration of D2EHPA and PC-88A were all 8.00x 10-2 mol/L in the membrane solution. However, Tb(III) separated from Dy(III) was 2.26, so Tb(III) and Dy(III) can be separated from Eu(III). When pH in the feed phase was adjusted to 2.00, in 80 min the separation factors of Dy(III) and Eu(III) separated from Tb(III) were 28.9 and 19.1 respectively, so Eu(III) and Dy(III)can be separated from Tb(III).5. Through the analysis of mass transfer, the driving force of transportation is differences of concentration of hydrogen ion between feed phase and dispersion phase. The kinetics of transportation of metal ion through liquld membrane is studied and the results indicated that the transport kinetics could be analyzed in the formalism of concatenation reaction. The rate equation of transportation was obtained. The transport kinetics parameters are calculated including k1,k2, tmax, Rmax,Jfmax and Jsmax. The transport kinetics parameters Af,△m, df and Dm are calculated through the DSLM system. The osmotic coefficient equation is obtained through the DSLM. The osmotic coefficient equation is proved by transportation experiment.更多还原