Modeling the competitive adsorption of water and methanoic acid on calcite and fluorite surfaces

Atomistic simulation techniques were used to investigate the interaction between the minerals calcite and fluorite with water and methanoic acid. The relative adsorption energies suggest that methanoic acid preferentially adsorbs onto fluorite surfaces, while adsorption of water is energetically preferred over methanoic acid on the calcite cleavage plane in agreement with experiment. The coverage and configuration of adsorbed methanoic acid on the surfaces depends largely on lattice spacing between the cations, and bridging between surface calcium atoms is highly favored. These findings have given an insight into interactions at the atomic level which indicate that modeling techniques should be capable of predicting adsorption behavior and designing collector molecules, which is of central importance to the mineral processing technique of flotation.