A review of classical theories and characterization techniques for the mineral particle wettability in flotation process

Abstract

Surface wettability of mineral particles is the key interface characteristic to control the flotation separation process. This work systematically summarized the classic theories and characterization techniques of wettability commonly used in the mineral flotation process. The Young's equation, Wenzel and Cassie-Baxter models were separately applied in interpreting the wetting behaviors of droplets on smooth under ideal conditions, rough and heterogeneous surfaces of mineral particles. Meanwhile, some novel analytical techniques of wettability, such as surface energy, low-field nuclear magnetic resonance (LF-NMR), molecular dynamics simulations (MDS), etc., have been gradually developed and adopted. The shortcomings in surface wettability research for mineral flotation were reviewed, such as contact angle hysteresis, pinning effects, and the difficulty in characterizing dynamic wetting processes on complex heterogeneous mineral surfaces. Future research should integrate traditional and novel characterization methods to overcome challenges in heterogeneous wetting on complex mineral surfaces. This review is crucial for deeply understanding the mineral surface wettability and further improving the flotation separation efficiency of mineral particles.