Phosphate ore washing by Na₂EDTA for cadmium removal: Optimization of the operating conditions

This paper discusses the extraction of cadmium from phosphate ore by the washing method. Various parameters were investigated for the cadmium extraction from phosphate ore. The results from extraction tests showed that cadmium extraction depends on the nature and concentration of the extracting agent, the liquid/phosphate ore ratio, the temperature and the solution pH. The effi ciency of the nine extracting agents for removing cadmium from phosphate ore was found to be in the order: Na2EDTA > citric acid > tartric acid > ammonium citrate > calcium chloride > ammonium acetate > ammonium chloride > oxalic acid > ammonium hydroxide. In this study cadmium extraction kinetics was best described by the product layer diffusion control model.