Process for separating heavy metal compounds from intermediates in the production of phosphate fertilisers

摘要

Process for separating heavy metal components from crude phosphoric acid which has been obtained by treating the crude phosphate with nitric acid and from which most of the calcium nitrate formed has been removed, in which the crude phosphoric acid is adjusted to a pH of between 0.5 and 1.5 using ammonia and extracted with a dithiophosphinic acid and/or a dithiophosphonic acid O-ester, if appropriate as a mixture with inert organic diluents.