Modeling of phosphoric acid purification contaminated by magnesium and cadmium

Abstract

The present study brings to light modeling of the purification of phosphoric acid, which is obtained through the wet process route. The said wet process inevitably is used to remove the impurities, mainly the heavy metal cations such as Mg²⁺, Cd²⁺, etc., which are initially present in the phosphate rocks and it is imperative that these impurities be removed . For the very same purpose, liquid–liquid extraction has proven to be one of the most reliable techniques and hence it is again considered, basing the model on the purely theoretical considerations of thermodynamics and mass transfer. The developed model was tested on two systems with Mg²⁺and Cd²⁺ as the contaminants and dinonylnaphthalene sulfonic acid and di (2-ethylhexyl) dithiophosphoric acid as complexing agents, both diluted in kerosene and dodecane, respectively. A parametric study was carried out, to investigate the effect of certain key parameters such as the phosphoric acid and the extractant initial concentrations.

Keywords:

• Phosphoric acid purification
• Extraction
• Magnesium
• Cadmium
• Phosphate
• Complexing agent

Notes

Presented at the International Conference on Desalination for the Environment, Clean Water and Energy, European Desalination Society, 23–26 April 2012, Barcelona, Spain