Pressure leaching of high silica Pb-Zn oxide ore in sulfuric acid medium

The pressure leaching of high silica Pb-Zn oxide ore using air as pressurized gas in sulfuric acid medium is studied systematically in the present paper. Study parameters include the concentration of sulfuric acid, partial air pressure, leaching temperature, leaching time, and liquid-to-solid ratio. The experimental results obtained show that under optimum conditions, the extraction percentage of Zn is up to 96% and the extent of dissolution of Si, Pb, and Fe are as low as 1%, 2%, and 6%, respectively. Leaching pulp had good filter performance, and the silicic acid formed during sulfuric acid leaching was transformed into easily filterable dehydrated SiO₂ particles that can enter the slag. The filtration rate can be as high as 893 L/m² h.