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Re-extn. of iron from organic soln. contg. citrate ester extractant - by pptn. in the aq. phase as iron phosphate by mixing with aq. phosphoric acid at 50-90 deg. C and iron:acid mol. ratio 1:2-4
Re-extn. of iron from organic soln. contg. citrate ester extractant - by pptn. in the aq. phase as iron phosphate by mixing with aq. phosphoric acid at 50-90 deg. C and iron:acid mol. ratio 1:2-4
A process is claimed for the re-extn. of iron from the Fe-contg. phase of a solvent extn. process, which contains citric acid partial ester(s) of formula (I) as extractant, dissolved in an organic solvent. The process comprises complete pptn. (as far as possible) of the Fe in the aq. phase as Fe phosphate (II), by mixing the organic phase with aq. H3PO4 at 50-90 deg. C, with mol. ratio Fe:H3PO4 = 1: (2-4). R1, R2, R3 = H, 4-20C linear or branched alkyl, or a metal atom; at least one or at most two of these R gps. = alkyl. Pref. re-extn. is carried out for 5-20 (esp. pref. 10-15) mins. at 60-80 deg. C, with mol. ratio Fe:acid = 1:(2.2-3). USE/ADVANTAGE - The process (`iron stripping') is useful for recovering iron from solns. obtd. by selective liq./liq. extn. of Fe from aq. solns. with the aid of solns. of (I); the process enables complete re-extn. of Fe in a short time, and does not require expensive equipment (centrifuges, etc.; contrast prior-art processes); (II) is pptd. in a very pure state and can be immediately re-used.
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