RECOVERY OF GOLD(III), PALLADIUM(II) AND PLATINUM(IV) IONS FROM CHLORIDE SOLUTIONS ON SOLVENT IMPREGNATED RESIN - PUROLITE® MN 202
Grzegorz WOJCIK*. Zbigniew HUBICKI, Magdalena GORSKA
University of Maria Curie-Sklodowska, Faculty of Chemistry, Department of Inorganic Chemistry PI. M. Curie-Sklodowskiej 2, 20-031 Lublin, Poland, *[email protected]
Precious metals: gold, palladium and platinum got to know and esteemed since ages with regard on one's special physical proprieties and chemical they found in many fields of life use, as early as from jeweller's craft, through catalysis, chemical processes and finishing on medicine. Gold was used as a medium of monetary exchange, some is used within the electronics, medicine or jewellery industries. The main uses of palladium are in the electronics or electrical industries and in medicine. It finds many catalytic applications in industry such synthesis of hydrogen and automobile catalysts [1]. Platinum and Palladium play an essential role in keeping the environmental devoid of pollutants appearing from vehicle exhausts. They are present in catalytic converters. Conventional "three-way converters" contain 0.08% Pt, 0.04% Pd and 0,005-0,007 Rh [2]. Platinum metals occur in polymetallic ores in nature as well as in diadochy substitutions in copper or silver minerals. Moreover, used up catalysts of various types, jewellery, electronic, ceramic etc., industry wastes are secondary raw materials of noble metals. Anode slimes formed in copper and nickel electrolytic refining are one of main sources of raw materials for preparation of platinum metals and gold. They the high price as well as extorted the difficult accessibility the need searches the new methods recovery of noble metals. Moreover, traditional methods to obtain these metals require using aggressive reagents and their use has a negative impact on the environment. Economic recovery is possible by using both ion- exchange and extraction methods. The solvent impregnated resins link ion-exchange and extraction processes. Research lead that ion exchangers without impregnation are not enough selective to remove select metals from large amounts of accompanying metals. This kind of resin posses selective for metals functional groups which are immobilize on the resin's matrix by chemical bonds or physical adsorption [3]. Impregnation of an organic extractant into a polymeric support offers several advantages over normal extraction systems, e.g.: 1. Ease of phase separation due to the elimination of problems dealing with the formation of stable emulsions,
270 2. Ease of solvent impregnated resin preparation, 3. Wide choice of reagents of desired selectivity[4]. The solvent impregnated resins are new sorbents for selective recovery of some precious metals from chloride solutions. There were carried out laboratory studies of selective removal of platinum(IV), gold(III) and palladium(II) microquantities from 0.1-6M hydrochloric acid solutions on the solvent impregnated macroporous polystyrene crosslinked with divinylobenzene resin Purolite MN 202 using Cyanex 272. In these experiments % R of gold(III), palladium(II) and platinum(IV) depending of time was obtained. Samples of impregnated resin (0,25 g) with 25 cm3 corresponding solution were mechanically shaken from 5 to 360 minutes Afterwards solution with impregnated resin was filtrated. The gold, palladium and platinum concentration was determined by the AAS method. The kinetic parameters were calculated on the basis of static results.
The studied impregnated sorbent characterizes the good sorption of ions Au(III) depend on concentration of hydrochloric acid and pH. By increasing concentration hydrochloric acid grew up to about 90 %R was observed. Sorption of ions Pt(IV) was worst then sorption of ion Au(III) and depends on hydrochloric concentration too. Sorption of ions Pd(II) wasn't observed. The described method using Purolite MN 202 for selective separation of ions gold(III), palladium(II), and platinum(IV) from hydrochloric solutions obtained that can be considered effective for separation gold and platinum from solution contains palladium.
REFERENCES
1. S. A. Cotton, Chemistry of precious metals, Chapman&Hall, 1997 2. K. Ravindra, L. Bencs, R. Van Grieken, Sci. Total Environ., 318(2004)4 3. J. L Cortina., E. Meinhardt, O. Roijals, V. Marti, React. Funct. Polym., 36(1998)150 4. B. Saha, R. J. Gill, D. G. Bailey, N. Kabay, M. Arda, React. Funct. Polym., 60(2004) 223
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