Abstract: The disclosure relates to a process for removing heavy metal ions and arsenic from wet-processed phosphoric acid, wherein the crude wet-processed phosphoric acid is treated at temperatures between 10.degree. and 100.degree. C. initially with a diorganyldithiosphosphoric acid ester and then with an adsorbent, and the phoshoric acid so purified is separated from the ester and adsorbent. More particularly, the wet-processed phosphoric acid is treated with the diorganyldithiophosphoric acid ester at temperatures higher than 50.degree. C. and with the adsorbent at temperatures lower than 50.degree. C.

Abstract: The present invention relates to a process for recovering uranium from raffinate which is obtained by extracting phosphoric acid from a uranium-containing wet-process phosphoric acid with the aid of organic extractants and separating the resulting organic phosphoric acid extract from residue not taken up by the extract. To this end, the raffinate residue is subjected to thermal treatment and thereby freed from dissolved or emulsified residual extractant. Next, the raffinate is treated with a water-immiscible solvent to extract the uranium, and the extracted uranium is separated from the undissolved raffinate portion.

Abstract: The disclosure relates to a process for after-treating extraction residues, termed raffinates, originating from the extractive decontamination of crude phosphoric acid. To this end, the disclosure provides for the raffinates to be converted to two separate solid matter fractions of differant chemical composition by admixing the raffinates with a calcium compound so as to establish a pH-value of 1.2 up to 2.5. Next, the resulting precipitate consisting essentially of gypsum is filtered off as a first solid matter fraction, and washed with water. The resulting filtrate and the wash water are made into a mixture and predetermined proportions of calcium compound are added so as to obtain, after complete reaction, a fully reacted filter cake with a pH-value of 9 up to 12, the resulting suspension being filtered off at a pH-value of 6 to 8. The filter cake consisting essentially of calcium phosphate is separated as the second solid matter fraction, and allowed to react completely.

Abstract: The disclosure relates to process for removing heavy metal ions, especially cadmium, copper, lead and mercury ions from wet-processed phosphoric acid. To this end, the crude acid is contacted with a mixture consisting of an adsorbent and a diorganyldithiophosphoric acid ester or, after treatment with the ester, the acid is contacted with the adsorbent alone, and the purified phosphoric acid is ultimately separated from the ester and adsorbent.

Abstract: The disclosure relates to a multistage column for countercurrent extraction of two liquids of different specific density therein. The column is comprised of a housing in upright position provided at its upper end with an upper inlet and upper outlet and, at its lower end, with a lower inlet and lower outlet, the upper inlet and lower outlet permitting specifically denser liquid to be introduced into the column and to be taken therefrom, and the lower inlet and upper outlet permitting specifically less dense liquid to be introduced into the column and to be taken therefrom. Arranged centrally within the housing so as to extend vertically downward therein is a shaft and a plurality of stirring means which are spaced apart from each other are secured to the shaft, perpendicularly with respect thereto. A plurality of annular stator collars are mounted within the region of the inside wall of the housing, the individual stator collars being arranged downstream of, and spaced apart from, each other.