US 4,762,692 AGranted

Process for the precipitation and separation of cadmium sulphide from the raffinates derived from phosphoric acid purification

AssigneeChemische Fabrik Budenheim Rudolf A. Oetker

InventorsKlaus Beltz, Klaus Frankenfeld, Peter Ruschke, Gerhard Eich

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Abstract

Disclosed is a process for the precipitation and separation of cadmium sulphide from the raffinates derived from phosphoric acid purification by treating the cadmium containing streams of the raffinates with a H.sub.2 S containing solvent phase in a mixing-settling apparatus, by separating the raffinate phase from the cadmium sulphide containing solvent phase and by separating the precipitated cadmium sulphide from the solvent phase. By operating this process it is possible to remove cadmium in a simple manner from the raffinates since their inherent properties don't influence the precipitation and separation of cadmium sulphide.

Claims13

Dependent claims

A process for the precipitation and separation of cadmium sulphide from a raffinate derived from purification of phosphoric acid, comprising the steps of:

treating an aqueous cadmium containing raffinate phase with a H.sub.2 S containing solvent phase under agitation conditions sufficient to produce a cadmium sulphide precipitate in the solvent phase;
separating the raffinate phase from the cadmium sulphide containing solvent phase;
and separating the precipitated cadmium sulphide from the solvent phase, wherein said H.sub.2 S containing solvent phase is miscible to partly miscible with water and phosphoric acid but substantially immiscible with the raffinate phase, and comprises an organic compound having up to 6 carbon atoms and at least one oxygen atom.

Dependencies are inferred from the claim text.