Interaction mechanisms between sub-bituminous coal particle and air bubble: Impact of collector adsorption

Abstract

The interaction between air bubbles and minerals surface plays essential role in mineral froth flotation. In this work, an atomic force microscope (AFM) colloidal probe technique was employed to directly measure the interaction forces between an air bubble and sub-bituminous coal (SBC) particle modified with polar (1-dodecanol)/nonpolar (dodecane) collectors, respectively. And the SBC particle-bubble attachment efficiency measurement was used to verify the AFM force measurement results. The adhesion force was found to be stronger for the air bubble-SBC particle modified with 1-dodecanol, which makes particle-bubble attachment efficiency higher than the dodecane-modified condition. The interaction forces between SBC particles and collectors were determined, and the adsorption behavior of the collector on the coal surface was studied by molecular dynamics (MD) simulation, aiming to reveal the underlying mechanism for the variation of collector-modified SBC particle-bubble interaction force. It was found that 1-dodecanol and SBC have stronger adhesion, which helps it to be more easily adsorbed on the SBC surface. The contact angle test and MD simulation results showed that the hydrophobicity of the SBC surface improved the most after the modification with 1-dodecanol, which in turn finally promoted the interaction between SBC surface and air bubble. This work may offer an interesting strategy for the targeted selection of collectors in the flotation process of SBC.