Treatment of wastewater containing dissolved metals by extraction-flotation

In this work an alternative process for treating a wastewater containing dissolved metals (uranium and zirconium) is considered. In order to develop this work, a continuous separation unit, characterized by the association of solvent extraction and liquid-liquid flotation is used. Alamina 336 (a mixture of tri-octyl and tri-decyl amines) is used as extractant in the the extraction process, carried out inward the ejector. The splitting of the amine-water emulsion formed is carried out in a continuously operated flotation column (of approximately 2.5 L volume). The solvent extraction results showed that it is possible to reach an efficiency of about 95% for the uranium and zirconium extraction, for a metal in the feed concentration of 10 ppm and for a Qfa/Qfo ratio around 200. An efficiency of about 80% is reached in the flotation column when the liquid flowrate is equal 0.05 Lmin-1 and the air flowrate is equal 3.3 Lmin-1. (author)