Interactive effect of particle size, liberation and hydrophobicity on the flotation kinetics of a carbonaceous phosphate deposit

Selective separation of apatite from the associated minerals (quartz, calcite and dolomite) in a carbonaceous phosphate ore type strongly depends on the interactive effect of particle size, hydrophobicity and mineral liberation degree (LD). This study aims to investigate these parameters by paying close attention to distinguishing true flotation (attachment) and entrainment phenomena respectively in pulp and froth zones. Modified flotation kinetics (kM) were used for estimating flotation rates of the different minerals on size-by-liberation in terms of taking the combination of infinitive recovery (Rmax) and k into account. The results indicate that the LD plays an insignificant role on kM of fine apatite particles (< 20 µm) due to transporting to the concentrate by both true flotation and entrainment mechanisms. In contrast, kM of the coarse apatite particles (> 20 µm) is strongly influenced by the LD. Additionally, the recovery of fully liberated apatite in the four studied size ranges was found fairly similar. However, both size and LD are significantly affecting the recovery of liberated gangue minerals where both true flotation and entrainment occurred for carbonates and entrainment for silicates.