SEARCH Articles Figures Tables S - Batch Vacuum Dezincing Plant, as at St. Joe, Herculaneum, See Reference The Distance Between the Evaporating and Condensing Surfaces is About 30 cm A Mechanical Vacuum Pump Produces a Residual Pressure of About 30 Microns Hg A Lead Temperature of 600 C and Stirring Time of 5 hours Reduced Zinc rom 0.56 to 0.05 Zn in the Dezinced Lead. [Publishers Imprint]