Hydrothermal Extraction of MoO42- Ion from Low Grade Molybdenite Oret

Abstract

The direct short time leaching of molybdate(VI) ion from low grade molybdenite ore (MoS₂; 2.1%) was carried out by the use of a microautoclave and the effects of temperature, oxygen over pressure, and NaOH concentration were examined. Both oxygen over pressure and NaOH concentration were found to control the extraction of molybdate(VI) ion. The dissolution of silica, however, was not affected by oxygen over pressure. Laboratory small batch studies have shown that molybdenite can be readily dissolved in dilute NaOH solution (0.2∼0.6 moldm^-3) under 150∼200°C and 5 MPa of oxygen over pressure, leaving Si, Al, Fe, Ca, and Mg in the residue.