Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, Russia:

Pashkov G. L., Сorresponding Member of RAS
Fleitlikh I. Yu., Leading Researcher
Grigorieva N. A., Senior Researcher, e-mail: natasha@icct.ru

LLC “Scientific-Research Centre “Gidrometallurgiya”, Saint-Petersburg, Russia:
Pleshkov M. A., Leading Researcher

The paper presents the data on the evaluation of the use of mixtures bis(2,2,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301^®) with organic amines for the nickel and cobalt SX recovery from the model leaching solution of oxidized nickel ores. Primary and secondary amines, as well as trialkylbenzylammonium chloride are not practically suitable for this purpose due to the different reasons, such as low solubility in an diluent, cobalt oxidation in an extract, stripping problems, etc. For the nickel and cobalt SX recovery only the systems based on the mixtures Cyanex 301^® with trialkylamine (TAA) and tributylphosphate (TBP) are applicable. 0.4 mol/l Cyanex 301® (HR) solutions in the diluent (kerosene, paraffine oil) with 0.4–0.5 mol/l TAA and 20% TBP were used as an extractant. The presence of TBP in the organic phase allows to avoid the precipitations during the extraction at high pH values (7.5), as well as to use of natrium extractant form (NaR) for the accurate pH-control in the extraction stages. Nickel and cobalt are efficiently extracted from solutions containing, g/l: 3–6 Ni; 0.3–0.6 Co; 0.1–0.2 Zn; 2.0–3.0 Mn; 0.4–0.6 Ca; 6.0–8.0 Mg, in the pH range of 6.2–6. The separation factors for non-ferrous metals (Со, Ni) and alkaline-earth metals (Са, Mg), as well as for Mn, achieve rather high values and vary within 102–103 depending on the experimental conditions. At the same time, extraction of metals from the solution is not less than 98%. Ni and Со stripping is carried out with a stoichiometric amount of sulfuric acid to extracted metals (1.5–2.0 mol/l concentration). Since the nickel strip liquors contain a small amount of free sulfuric acid (pH 1.5–2.0), after purification of the solutions from cobalt and zinc, these solutions can be processed by the use of traditional technologies, for example, using electrolytic or precipitative methods.

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