Process for the precipitation and removal of cadmium from the raffinates of phosphoric acid purification

摘要

The present application is an addition to the main application P 3622597.5 and is a variant of the process for precipitation and removal of cadmium sulphide from the raffinates of phosphoric acid purification with the aid of polysulphanes, by treating the cadmium-containing raffinate streams with a solvent phase in the presence of polysulphanes in a mixer-settler apparatus, separating off the raffinate phase from the solvent phase containing cadmium sulphide and isolating the precipitated cadmium sulphide from the solvent phase. With the aid of the process, the raffinates can be freed of cadmium in a simple way, since their inherent properties have no influence on the precipitation and removal of the cadmium sulphide.