COPPER RECOVERY FROM AMMONIACAL MEDIA USING HOLLOW FIBRE CONTACTORS
Advancing the chemical engineering fundamentals
Distillation, Absorption & Extraction (T2-10P)
Keywords: Copper extraction, LIX 54-100, LIX 84-I, Hollow fibre, Waste treatment.
M. Lurdes F. Gameiro, M. Rosinda C. Ismael, M. Teresa A. Reis, Jorge M. R. Carvalho*
Department of Chemical and Biological Engineering, Instituto Superior Técnico,
Av. Rovisco Pais, 1049-001 Lisboa, Portugal
* Corresponding Author
This work aims to study the extraction of copper from ammoniacal aqueous solutions using hydrophobic propylene membrane contactors.
The hollow fibre contactors present several advantages: a very large contact area without direct mixing of the aqueous and organic phases, the capability of treating a large amount of dilute solutions, and the reduction in equipment volume and space (Juang and Huang, 2000). Such microporous membrane-based dispersion-free extraction has been developed to avoid many of the problems associated with conventional liquid-liquid extraction including solvent losses, emulsion formation, phase separation, and the shortcomings due to flooding in conventional column contactors and mixer-settlers.
The ammoniacal leaching is an attractive approach to process concentrates, wastes, and by-products containing copper since this metal ion is easily solubilised through the formation of ammine complexes [Nathsarma and Sarma, 1993; Campbell et al., 2002]. The recovery of copper from such leach solutions can be carried out by solvent extraction processes due to their versatility to remove and to separate efficiently metal ions from aqueous solutions when a suitable extractant is used. Specifically for copper extraction, the well-established extractants are hydroxyoximes (ex.: LIX 860 and LIX 84-I (Cognis), SME 529 (Shell), P50 and P5100 (Acorga)), and β-diketones (ex.: LIX 54-100 (Cognis)) [Schwab and Kehl, 1997; Kyuchoukov et al., 1998; Hu and Wiencek, 2000; Ismael and Carvalho, 2002].
In the present study, the hydroxyoxime LIX 84-I (Cognis) and the β-diketone LIX 54-100 (Cognis) were used as extractants. The influence of the aqueous and organic throughputs on the overall mass transfer coefficient was determined for both systems to select the optimum hydrodynamic conditions. Simultaneous extraction and stripping experiments using different volume phase ratios and different initial copper concentrations in the feed phase were carried out. Concentration ratios of about 38-fold with 99% recovery were obtained. The use of hollow fibre contactors showed to be adequate for the extraction and stripping of copper with LIX 84-I and LIX 54-100.
The results were finally compared with the ones obtained by applying the Emulsion Liquid Membranes (ELM) separation technique. The extraction efficiencies and the concentration ratios obtained with the latter configuration of membranes are lower than the ones obtained for the non-dispersive solvent extraction, due to non-ideal phenomena occurrence, like water transport and break-up. However, the transferred solute quantity per area and time unit is higher for the ELM, because in this case there isn’t any fibre resistance to mass transfer.
REFERENCES
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Hu, S.-Y.; Wiencek, J.; 2000; “Copper-LIX 84 extraction equilibrium”; Solvent Extraction and Ion Exchange; 35 (4); 469-481.
Ismael, M. R. C.; Carvalho, J. M. R.; 2002; “Copper recovery from spent ammoniacal etching solutions” – Proceedings of International Solvent Extraction Conference (ISEC´2002); 2; 781-786.
Juang, R.-S.; Huang, I-P.; 2000; “Hollow-fiber membrane extraction of copper(II) from aqueous ethylenediaminetetraacetic acid solutions with Aliquat 336”; Ind. Eng. Chem. Res.; 39; 1409-1415.
Kyuchoukov, G.; Bogacki, M. B.; Szymanowski, J.; 1998; “Copper extraction from ammoniacal solutions with LIX 84 and LIX 54”; Ind. Eng. Chem. Res.; 37; 4084-4089.
Nathsarma, K. C.; Sarma, P. V. R. B.; 1993; “Processing of ammoniacal solutions containing copper, nickel and cobalt for metal separation”; Hydrometallurgy; 33 (1-2); 197-210.
Schwab, W.; Kehl, R.; 1997; “Copper recycling from spent ammoniacal etching solutions and their regeneration by solvent exytraction”; Proc. of XX Int. Mineral Processing Congress; 4; 285-292.
See the full pdf manuscript of the abstract.
Presented Tuesday 18, 13:30 to 15:00, in session Distillation, Absorption & Extraction (T2-10P).
