用盐酸从矿泥中浸出稀土的动力学控制分析

某风化矿泥含稀土在2%～5%,且稀土以氧化物形式存在于矿泥中。用盐酸加热浸取可将稀土浸出,转化为氯化稀土,再用草酸沉淀回收稀土。分析了盐酸浸出稀土的条件和动力学,其速率常数k=(760+0.64×1/ro2)exp(-10500/RT),表观活化能为10.5kJ/mol,是一个典型的内扩散控制过程。温度越高,矿泥粒度越细,越有利于稀土的回收。

Analysis of Kinetics Control on Leaching Rare Earth from Weathered with Hydrochloric Acid

The leaching kinetics of rare earth from weathered mud located in Southwestern China was studied. Solution of rare earth chloride was obtained after leaching the weathered mud with hydrochloric acid under heating and agitation. The rare earth was then extracted by precipitation using oxalic acid. An empirical equation relating to the rare earth leaching rate constant with feed -particle size and leaching temperature was established as k=(760+0.64 1/r_o~2)(exp(-10500/RT)). It was found that the leaching process is controlled by an inner diffusion. A higher recovery of rare earth was obtained by a higher leaching temperature and/or a smaller particle size.