Abstract:
Mechanical activation (MA) of malachite was carried out by dry planetary grinding (DPG) and wet Isa grinding (WIG) methods. When the rotational speed was increased to 400 r/min in DPG, the specific surface area of malachite reached the maximum and the particle size reached the minimum of 0.7–100 μm. Agglomeration occurred between mineral particles when the rotational speed was increased to 580 r/min in DPG. However, no agglomeration was observed among particles with sizes 0.4–3 μm in WIG. X-ray diffraction analysis showed that, at a 580 r/min rotational speed in DPG, the amorphization degree of malachite was 53.12%, whereas that in WIG was 71.40%, indicating that MA led to amorphization and distortion of crystal structures. In addition, in the Fourier transform infrared (FT-IR) spectra of activated malachite, the bands associated with –OH,
\rm CO_3^2- and metal lattice vibrations of Cu–O and Cu–OH were weakened, and a new H–O–H bending mode and peaks of gaseous CO
2 appeared, indicating that MA decreased the band energy, enhanced dihydroxylation, and increased the chemical reactivity of the malachite. Furthermore, the leaching behavior of copper ore was greatly improved by MA.