PROCESS FOR SEPARATING HEAVY METAL VALUES FROM INTERMEDIATE PRODUCTS IN THE MANUFACTURE OF PHOSPHATIC FERTILIZERS

摘要

1. A process for the separation of cadmium- or mercury-compounds from crude phosphoric acids which are produced by solubilization of crude phosphate by means of nitric acid and by removing the main fraction of the calcium nitrate thus formed which comprises adjusting the pH of the crude phosphoric acid by means of ammonia to a value between 0.5 and 1.5 and extracting the phosphoric acid solution with an organic phosphor compound of formula I, see diagramm : EP0078051,P6,F2 wherein R1 and R2 are identical or different and are saturated or unsaturated aliphatic, araliphatic or aromatic (C1 -C18 )-hydrocarbon radicals which are optionally substituted, and R1 and R2 together have 6 to 36 C-atoms, and optionally form together a substituted twice bonded radical, and n is independently of one another 0 or 1, or with a mixture thereof.