| 摘要 |
<p>Zinc is recovered from hard zinc (a) pptd., during dezincation, onto a molten bath of lead, where Pb is removed from the molten Pb bath, heated to 600-800 degrees C, fed through the hard zinc (a) and then returned to a zinc bath. The hard Zn (a) pref. floats on Pb at 600-850 degrees C and is treated with a stream of Pb at 600-850 degrees C, the Pb enriched with Zn and also contg. hard Zn (a) then being returned to the Zn bath. The zn is pref. recovered from the hard Zn (a) in an atmos. impoverished in O2, esp. in a protective gas or under a layer of salt. The pref. plant includes a tank (b) contg. Zn floating of a bath of Pb which is fed through a furnace and into a bath (a) of hard Zn floating in a ceramic tube on top of a second lead both in a tank (c); and tank (c) has an overflow leading to tank (b). Used in the hot dip coating of ferrous metal parts, e.g. screws with Zn, where the Fe and the Zn form crystals of hard zinc (a) which must be removed from the galvanising tank. Method is used to recover Zn from the hard Zn (a).</p> |
