Abstract: Zinc metal is deposited on mobile seed particles in an electrowinning process. Exceptionally favorable results in terms of production rate, current efficiency and energy consumption are achieved by using a unique combination of design parameters and operating conditions achieved by selected ranges for particle size, current density, particle bed thickness, and acid content of the electrolyte.

Abstract: A method and apparatus for determining electrochemically active components in a process stream. The method comprises the steps of providing a sample in which the components are contained, and depositing the components onto a working electrode, altering the environment of the working electrode so that it is immersed in a supporting electrolyte by effecting a matrix exchange and stripping the deposited electrochemically active components from the working electrode into the supporting electrolyte. The method and apparatus utilize a measurement cell which comprises a vessel (10) for containing the supporting electrolyte and a mercury drop electrode (150).

Abstract: A process for controlling the water balance and the concentration of impurities in an electrolytic zinc plant circuit with which is operated at least one selective zinc precipitation (SZP) process plant which comprises one or more of the steps(a) a two-stage SZP process plant in which a compound containing calcium carbonate is used in the first-stage to precipitate portion of the zinc in incoming solution, and a compound R containing zinc oxide, preferably calcined zinc sulphide concentrate, is used to precipitate most of the remaining zinc;(b) displacement of the zinc depleted solution associated with solids leaving the SZP process plant by solution drawn from the electrolytic zinc plant circuit, and(c) use of a compound R with a particular average particle size.