Modeling purification of phosphoric acid contaminated with cadmium by liquid-liquid extraction

Phosphoric acid production is considered as second worldwide after that of sulphuric acid. It is an important and necessary intermediate chemical compound in sensitive industrial fields such as the fertilizers, detergents, food, pharmaceutical industries. Its main production is through the wet process which is responsible for the presence of various impurities like metallic cations such as Pb-2 (+), Cd-2 (+), Mg-2 (+), etc, initially contained in the phosphate rocks. Indeed many techniques for the purification of phosphoric acid have been developed. In this work the modeling of the purification of phosphoric acid by liquid-liquid extraction was considered. The model was tested on Cd-2 (+) as contaminant and di (2ethylhexyl) dithiophosphoric acid diluted in dodecane as complexing agent. The results obtained from a parametric study investigating the effect of the initial concentrations of phosphoric acid and that of the complexing agent, are reported. (C) 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility of The TerraGreen Society.