Modeling of the equilibria of yttrium(III) and europium(III) solvent extraction from nitric acid with PC-88A
Modeling of the equilibria of yttrium(III) and europium(III) solvent extraction from nitric acid with PC-88A
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DOI：
10.2320/matertrans.47.136
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发表时间：
2006-01-01
影响因子：
1.2
通讯作者：
Tanaka, M
中科院分区：
文献类型：
--
作者：
Fu, NX;Tanaka, M
在非理想条件下，研究了PC-88 A溶解于Shellsol D 70中从硝酸溶液中萃取钇（III）和铕（III）的平衡，建立了一个基于化学的模型，用于工程预测平衡分配比。还考察了萃取剂在硝酸盐溶液和稀释剂之间的分配。结果发现，（i）大部分PC-88 A在有机相中二聚化，（ii）阳离子交换萃取在低酸度区域占主导地位，（iii）溶剂化萃取在高酸度区域变得明显。采用考虑RE与NO_3 ~-络合、PC-88 A溶液的非理想性和HNO_3竞争萃取的萃取平衡模型，用非线性最小二乘法确定了萃取平衡常数和萃取剂有效浓度系数。该模型能较好地再现单金属体系的实验数据，在较宽的稀土进料浓度范围内（最高可达0.1kmol.）m（-3）。硝酸（0.05 - 3 kmol（.）m（-3））和萃取剂（0.25 - 1 kmol（.）m（-3））。同时也证实了该模型对二元金属体系萃取前沿的适用性.
The equilibria of yttrium(III) and europium(III) (RE) extraction with PC-88A dissolved in Shellsol D70 from nitric acid solutions were studied under nonideal conditions in order to develop a chemically-based model enabling the engineering prediction of the equilibrium distribution ratios. The distribution of the extractant between the nitrate solution and the diluent was also examined. As a result, it was found that (i) the majority of PC-88A is dimerized in the organic phase, (ii) the cation exchange extraction is predominant in the low-acidity region, and (iii) solvation extraction becomes appreciable in the high-acidity region. By using a model that considers these two extraction equilibria together with the complexation of the RE with NO3-, the nonideality of the PC-88A dinner, and the competing extraction of HNO3, the extraction equilibrium constants and the coefficient for the effective concentration of the extractant were determined by the nonlinear least-squares method. The proposed model can reproduce the experimental data with good accuracy for single-metel systems over wide feed concentration ranges of RE up to 0.1 kmol(.)m(-3). nitric acid (0.05 to 3kmol(.)m(-3)), and the extractant (0.25 to 1 kmol(.)m(-3)). Its applicability to the prediction of the extraction front a binary metal system was also confirmed.