N-263对钨和钼的萃取机理研究与平衡pH的选择

本文对N-263在萃取钨和钼的过程中发生的萃取机理与pH值的改变进行了测量和研究。试验结果表明,季铵盐,N-263,在从钨酸钠溶液中萃取钨和钼的过程中,萃取前pH与萃取后的平衡pH之间发生了规律性改变;平衡pH对于分配比与分离系数的影响起到了至关重要的作用。严格控制萃取反应的平衡pH值,不仅影响到分配比,而且,影响到化学性质相近的钨和钼之间的分离效率。萃取剂,N-263对于钨和钼等阴离子的萃取反应和机理,是由萃取终点的平衡pH决定的。对于酸性溶液而言,萃取过程发生pH的升高现象,对于碱性溶液而言,萃取将发生pH的下降现象。萃取机理研究表明,萃取钨的最佳平衡pH为7。如果将溶液萃取前的pH值调整到接近中性,那么平衡pH变化极小。

Distribution Behavior of Aminobenzoic Acid by Extraction with Di(2-ethylhexyl)phosphoric Acid

A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.