Process for separating heavy-metal components from intermediates in the production of phosphorus fertilisers

摘要

Process for the separation of heavy-metal components from crude phosphoric acid which had been obtained by digesting crude phosphate with nitric acid and from which most of the calcium nitrate had been removed, by extraction of the crude phosphoric acid whose pH has been brought to a value of between 0.5 and 1.5 by means of ammonia, with a dithiophosphoric acid diester, if appropriate in the form of a mixture with inert organic diluents.