Chloride leaching of lanthanum and cerium from Indian red mud and metal separation studies

Abstract

Bench-scale experiments were conducted to recover lanthanum and cerium from Indian red mud in a hydrochloric acid medium. The method includes acid leaching of red mud pulp and subsequent liquid-liquid extraction of the leached metals with different organic extractants, in order to establish the technical feasibility of extraction and separation simultaneously. The maximum extraction of 88.5% La was achieved at 95 °C, using 1 M HCl, S/L ratio = 1/100 in 1 h with 200 rpm agitation rate. At this temperature, cerium recovery (99.9%) was found to be maximum. The maximum recovery of cerium (99.9%) can be achieved even at 55 °C, while the recovery of lanthanum lowered to 78.5% under same conditions. Liquid-liquid extraction of leached metals was tested to be complete and selective using Cyanex 923, as against Cyanex 301 and Cyanex 272.