| 摘要 |
<p>Zinc is selectively extracted from aq. solns. contg. Zn and other metals, esp. Fe salts, using virtually water-insoluble monohydric acids of formula R1R2P(=O)OH (I) in which R1 and R2 each is aliphatic, cycloaliphatic, araliphatic or opt. substd. aromatic gp. and one or both gps. may be bound to P by an O atom. (I) may be used in conjuction with a water-immiscible solvent and the two phases are intimately mixed for the min. possible contact time, and in any case is not >60 seconds. The short contact time ensures selective extn. of Zn, with little removal of Fe-(III). Losses of extn. agent (I) by formation of the stable (I)-Fe complex are reduced cf. prior art processes. Pref. the soln. is acidified with H2SO4 to pH0-6 before extn. and the process is at 0-50 degrees C, esp. 10-30 degrees C in a centrifugal extractor with a contact time of 3-15 seconds. Pref. (I) is di- (2-ethylhexyl) phosphoric acid (II).</p> |
