Particle-based modelling applied to understand the influence of comminution environment on the flotation of semi-soluble salt type minerals

Semi-soluble salt type minerals (SSSM) are important industrial minerals as well as common gangue minerals in diverse metal deposits. Being able to understand and improve the process behaviour of these minerals is thus of high relevance for many parts of the raw materials value chain. The surface properties as well as the interactions of these minerals with the fluid media grant them a distinguishable behaviour in flotation. In this study, we investigate the influence of particle geometric properties (size and shape) caused by distinct comminution environments (dry, wet, and wet with reagents) on the process behaviour of three ore types containing SSSM: an apatite, a fluorite, and a scheelite ore. A particle-based separation modelling method was applied to quantify the flotation kinetics of individual particles according to all tangible properties quantifiable with automated mineralogy (modal and surface composition, size, and shape). Our approach, which requires minimal human-input, captured well-documented flotation behaviours related to particle size (e.g., the Rmax of minerals recovered via entrainment is generally higher for the fine size fraction). In regards to particle shape, it clearly influences the flotation behaviour of particles. Yet, even in a controlled study such as we have performed here, the relation between mineral type, grinding environment, and flotation performance is very convoluted and no general conclusion can be drawn. This challenge in evaluating the influence of particle shape in flotation can explain the high number of controversial studies regarding the topic.