两组分稀土分馏萃取体系原料组成对纯度梯度和积累量的影响

Effect of Feed Composition on Purity Gradient and Accumulation in Two Component Countercurrent Extraction System

提出了两组分两出口分馏萃取体系中纯度梯度、积累量与纯度关系的数学表示式，利用静态和动态仿真计算程序，对不同分离系数、原料组成和出口纯度的两组分两出口分馏萃取体系的纯度、纯度梯度和积累量进行了模拟计算。结果表明：各组分两相纯度梯度在萃取段和洗涤段存在极值点。随着原料中难萃组分含量的增大，它在两相中的积累量随之增加，同时该组分萃取段纯度梯度的绝对值逐渐减小，而洗涤段的纯度梯度绝对值则逐渐增大。此外还比较了纯度梯度和积累量作为自控监测参数的特点，并得出对在线分析精度的要求和灵敏区位置。

The relationships and mathematical expressions between the purity gradient, accumulation and purity distribution in two component countercurrent extraction system were studied. By the static and dynamic simulation, the purity distribution curves with different feed composition and separation factor were calculated, and the related purity gradient and accumulation curves were derived. The results show that there are purity gradient maxima in both extraction and scrubbing section for each component in both aqueous and organic phases. The accumulation of each component in both phases increases with its content in the feed. Meanwhile, its net variation of purity gradient decreases in extraction section and increases in scrubbing section. Furthermore, the purity gradient and accumulation as the detecting parameters for automatic control were evaluated. The precision of online analysis in sensitive point and the range of accumulation were also estimated.