GB395602A - Purifying zinc metal - Google Patents

Abstract

395,602. Distilling zinc. NEW JERSEY ZINC CO., 160, Front Street, New York, U.S.A.-(Assignees of Ginder, P. M., Peirce, W. M., and Waring, R. K. ; Palmerton, Pennsylvania, U.S.A.) Dec. 23, 1932, No. 36503. Convention date, July 2. [Class 82 (i).] Zinc contaminated with more volatile impurities such as cadmium is purified by passing the vapour upwards through a rectifying column in countercurrent with descending molten metal, the purified metal being removed from the bottom and the cadmium &c. at the top. In the form shown in Fig. 1, zinc contaminated with cadmium &c. is vaporized in a retort 10, and the metal vapour passes into a heat-insulated rectifying column 14 which comprises baffle plates 15 on which molten metal is retained in shallow pools. The cadmium-rich distillate escapes through an outlet 18, while the purified zinc passes back to the retort from which it may be tapped at 12. In the plant shown in Fig. 3, impure molten zinc is charged through a tube 21 to the base of a rectifying column 14 which has an externally heated downward extension 14<1>. Cadmiumrich zinc vapour escapes from an outlet 32, and refined zinc is tapped at 27. In other forms, the column may comprise a series of shallow saucers each having an edge cut away and arranged in staggered form, and the purified zinc may be removed at an annular sump above the lower section of the column. The cadmiumrich vapour may be completely condensed by means of a closed condenser surmounting the top of the column and provided with an annular sump furnished with a tap-hole. Specification 392,361 is referred to.