Different Aryl Thiourea Compounds as Flotation Collectors in a Lead–Zinc Sulfide Mixed System

The primary coexisting mineral with galena is sphalerite. Hence, it is critical to selectively separate galena from sphalerite by flotation. In this work, thiourea and related derivatives as potential flotation collectors for separating galena from sphalerite were investigated. Thiourea and its related derivatives were found to be effective selective collectors in batch flotation studies of a single mineral, with 1,1-diphenylthiourea (11DTA) emerging as the best choice. Galena has superior floatability compared to sphalerite in the presence of 11DTA, and the recovery difference between the two minerals at pH 8 (where the 11DTA concentration is 5 × 10−6 mol/L) is around 38%. This was revealed in batch flotation studies using artificial mixed minerals. Moreover, the findings from the measurements of adsorption amount, FTIR, zeta potential and XPS revealed that 11DTA has a strong adsorption on galena yet a relatively weak adsorption on sphalerite. Additionally, DFT calculations demonstrated that sphalerite exhibits stronger hydrophilicity than galena, and 11DTA possessed a better affinity for galena.