Hydration effects in quaternary amine extraction systems
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The following metal ions were involved in this study: A1 *§247Cd *§ Co ++, Cu § Cu *§ Fe *§ Fe §247247 Ni §247and Zn*§ complexing ligands were choride and sulfate. Distilled water was used for the aqueous phase, while the organic phase consisted of axylene-isodecanol carrier and Aliquat 336, a methyltricapryl amine, as extractant. This amine is 90 pct active and has an average molecular weight of 442 in the chloride form. In all cases the organic phase consisted of 10 pct isodecanol by volume. All chemicals were reagent grade with the exception of the isodecanol and the amine. Experimentally, the two phases were shaken for 2 rain in a 250 ml separatory funnel at a temperature of 23 + 2~ The phase ratio in all experiments was unity. After contact, metal content of the aqueous phase was measured utilizing an atomic absorption unit. Metal content of the organic was then determined by difference. In addition to d e t e r m i n i n g the extent to which ext r a c t i o n of complex m e t a l a n i o n s had o c c u r r e d , the w a t e r content of the o r g a n i c p h a s e was m e a s u r e d as a function of loading in both the z i n c - and c a d m i u m J. D. MILLER is Assistant Professor of Metallurgyand Metallurgical Engineering, University of Utah, Salt Lake City, Utah. M. C. FUERSTENAU is Professor and Head, Department of MetallurgicalEngineering, South Dakota School of Minesand Technology, S. Dak. Manuscript submitted May 19, 1969. METALLURGICALTRANSACTIONS
chloride s y s t e m s . This m e a s u r e m e n t was made by e l e c t r o m e t r i c K a r l F i s c h e r t i t r a t i o n . O r g a n i c phase s a m p l e s were c e n t r i f u g e d for 1/2 hr to r e m o v e m e chanically e n t r a p p e d water. EXPERIMENTAL RESULTS Extraction data are presented in one of two ways, that is, either as a distribution isotherm or as a plot of the logarithm of the distribution coefficient vs the logarithm of the vol pct free amine. The first ligand used was chloride and when Ni §247 Fe §247and/%1 §247247 were involved, no extraction was effected under the m a n y conditions imposed. All of the other metal ions were extracted from chloride solutions. The distribution isotherm for the zinc-chloride system is shown in Fig. I. Since this system contained 5 vol pet amine, a mole ratio of amine to zinc of 2:1 is approached on m a x i m u m loading. The s a m e figure shows that the concentration of water in the organic phase is decreased by 0.88 g per liter when 4.04 • 10 -2 mole per liter Zn is extracted. For each mole of zinc that is extracted then, 1 mole of water is removed f r o m the o r g a n i c . Data a r e also p r e s e n t e d as the l o g a r i t h m of the d i s t r i b u t i o n coefficient vs the l o g a r i t h m of vol pct f r e e a m i n e . As shown in Fig. 2, a s t r a i g h t l i n e of slope 1.94 • 0.05 at 99 pct confidence is obtained. S i m i l a r r e s u l t s w e r e obtained in the c a d m i u m chloride s y s t e m . See F i g s . 3 and 4. The d i s t r i b u t i o n i
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