Sulfuric acid leaching of zinc silicate ore under pressure

Pressure acid leaching of zinc silicate ores selectively separates valuable zinc from silica and iron, replacing conventional pyrometallurgical and hydrometallurgical methods. This study determines the optimum conditions for the dissolution of zinc silicate concentrates and achieves a higher zinc extraction (> 97%), lower iron (< 0.77%) and silica dissolution (< 4%) with a high selectivity. The optimum conditions were found to be 140 °C, 1.4 MPa partial pressure, solid to liquid ratio (g/mL) 1:6, sulfuric acid concentration 0.44 mol/L, for 120 min using 98 μm ore particle size.

Research Highlights
► The filterable silica during pressure leaching will be formed.
► The process achieves a higher zinc extraction (> 97%).
► Impurity content, such as iron content, is on a very low level under pressure leaching.
► The technology is available to meet the environment-friendly requirement.