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Solvent extraction of nickel from acidic solutions using synergistic mixtures containing pyridinecarboxylate esters. Part 1. Systems based on organophosphorus acids
Author(s) -
Preston John S.,
du Preez Anna C.
Publication year - 1996
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/(sici)1097-4660(199605)66:1<86::aid-jctb456>3.0.co;2-9
Subject(s) - chemistry , phosphoric acid , nickel , reagent , extraction (chemistry) , magnesium , liquid–liquid extraction , inorganic chemistry , solvent , pyridine , copper , nuclear chemistry , organic chemistry
The solvent extraction of nickel from acidic solutions by pyridinecarboxylate esters (2‐, 3‐ and 4‐C 5 H 4 N.CO.OR) mixed with organophosphorus acids (R 2 POOH, (RO)RPOOH and (RO) 2 POOH) in toluene was investigated for both series of compounds in which R = n ‐octyl, 2‐ethylhexyl and cyclooctyl. Substantial synergistic effects were observed, which increased in the orders: pyridine 2‐ester < 3‐ester < 4‐ester, and: phosphinic < phosphonic < phosphoric acid. The extractability of divalent base metals from sulphate solutions by mixtures of isodecyl 4‐pyridinecarboxylate and di(2‐ethylhexyl) phosphoric acid in Shellsol K decreases through the series Cu > Ni > Zn > Co > Ca > Mg. In a batch countercurrent experiment, a simulated leach liquor containing Ni 2·1, Cu 0·5, Ca 0·4 and Mg 5·0 g dm −3 (initial pH 3·00) was extracted with the mixed reagent (0·50 M ) in four stages at unit phase ratio, without pH adjustment. Recoveries of nickel and copper were 93 and 100%, with co‐extractions of calcium and magnesium of 10 and 1%, respectively. In a similar experiment using isodecyl 3‐pyridinecarboxylate in place of the 4‐isomer, the overall extractions were nickel 80, copper 100, calcium 17 and magnesium 3%.