Preparation of montmorillonite clays containing DTMPPA for Zinc extraction

Di(2,4,4-trimethylpentyl)phosphinic acid, 'DTMPPA' (Cyanex 272), was introduced into homoionic clays containing sodium by using two methods: a dry impregnation method (process 1) and an intercalation method (process 2). The total amount of loaded extractant was determined by NaOH titration of washings and/or mother-solutions in both cases. The solids obtained were characterized by infrared spectroscopy (IR), X-Ray diffraction and TGA-DTA analysis. The montmorillonite clays containing DTMPPA were used to successfully remove zinc from sulphuric dilute acidic solutions (pH 2-5), at constant ionic strength, I=1. The metal extraction depends on pH. The clay containing DTMPPA loaded by process 1, that contains more DTMPPA than the clay loaded by process 2, shows a better performance in the extraction of zinc.