Effect of dissolved components of malachite and calcite on surface properties and flotation behavior

In general, malachite is recovered via sulfidization–xanthate flotation, although many unsatisfactory flotation indexes are frequently obtained as a result of the presence of associated calcite. This phenomenon occurs because the dissolved components of malachite and calcite affect the flotation behavior of both minerals. In this study, the effect of the dissolved components derived from malachite and calcite on the flotation behavior and surface characteristics of both minerals was investigated. Flotation tests indicated that malachite recovery decreased when the calcite supernatant was introduced, while the presence of the malachite supernatant increased the recovery of calcite. Dissolution and adsorption tests, along with zeta potential measurements, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometry, and time-of-flight secondary ion mass spectrometry demonstrated that the Ca species in the calcite supernatant were adsorbed on the malachite surface, which hindered the interaction of Na₂S with malachite, thereby resulting in the insufficient adsorption of sodium isoamyl xanthate (NaIX) on the surface of malachite. By contrast, the Cu species in the malachite supernatant were adsorbed on the calcite surface, and they provided active sites for the subsequent adsorption of Na₂S and NaIX.