BOPI 07 BR/2023 REPERTOIRE NUMERIQUE 23 between the heavy metals, in particular cadmium, and the organothiophosphorous precipitating agent is performed at a pH ranging between 1.6 and 2.0 measured after a 13-fold dilution by volume. Advantageously, an ionic polymer, particularly a cationic and/or an anionic poly(meth)acrylamide copolymer may be used to promote heavy metal precipitation and/or to facilitate the removal of the precipitates from the composition. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof. Fig. 1 Consulter le mémoire ________________________________________ (11) 21049 (51) B09B 3/00 (2018.01); C01B 25/234 (2018.01); C01G 11/00 (2018.01); C01G 13/00 (2018.01); C01G 21/00 (2018.01); C22B 3/16 (2018.01); C22B 3/44 (2018.01) ; C22B 7/00 (2018.01) (21) 1202200434 - PCT/EP2021/066174 (22) 16/06/2021 (30) EP n° 20180341.8 du 16/06/2020; EP n° 20195106.8 du 08/09/2020 (54) Process for the removal of heavy metals from a phosphoric acid containing composition using a flocculating agent. (72) KITA, Patrycja (PL); VOJNOVIC, Tanja (NO); JØRGENSEN, Tom Rames (NO) et JORDBRÆK, Per Arne (NO) (73) YARA INTERNATIONAL ASA, Drammensveien 131, 0277 OSLO (NO) (74) Cabinet BONNY & ASSOCIÉS, LAW FIRM, B.P. 35349, YAOUNDE (CM). (57) The present disclosure provides improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, wherein an ionic polymeric flocculating agent is added to a phosphoric acid containing composition subsequent to the addition of an organothiophosphorous heavy metal precipitating agent to said composition, particularly under gentle mixing conditions, such as between 100 and 300 rpm. The flocculating agent promotes the formation of agglomerates of the heavy metal containing precipitate, thus facilitating their removal from the composition. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock; Dreferably by nitric acid, sulfuric acid, or a combination thereof. Fig. 1
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