Magnetic property of malachite for high-gradient magnetic separation

Malachite (CuCO3 center dot Cu(OH)2) has long been considered a non-magnetic mineral, so it is never believed separable with magnetic separation. The findings from this innovative research would change this deep-seated view. For the first time, malachite was found to own a magnetic susceptibility even larger than chalcopyrite, and the theoretical analysis based on the Density Functional Theory (DFT) and Crystal-Field Theory (CFT) calculations revealed that the magnetic susceptibility of malachite is originated from the hybridization and spin of electrons in the Cu and O atoms in the malachite structure, as a result of the Jahn-Teller effect. The experimental investigation showed that the malachite is separable through high gradient magnetic separation (HGMS). By feeding a malachite ore sample assaying 0.80 % Cu with a particle size of D60 = 74 mu m, the SLon-100 pulsating HGMS separator produced a malachite concentrate assaying 0.968 % Cu at 87.37 % recovery; and, the discarded tailings from the separator was significantly reduced to 0.364 % Cu at a mass weight reaching 27.80 %. These innovative findings provide a more environment-friendly and economical solution for high-efficient separation of malachite using HGMS method.