Components of surface free energy of galena

Abstract

Measurements of the contact angle for water, diiodomethane, bromoform and 1,1,2,2-tetrabromoethane on non-oxidized and oxidized surfaces of galena were made. Using the results obtained, the “geometric mean” approach, and the long-range and short-range interactions approaches, the dispersion and non-dispersion, and Lifshitz-van der Waals and acid-base components of the surface free energy of galena were determined and compared with those calculated from adsorption isotherms ofn-octane andn-propanol. On the basis of the measurements and calculations it was found that the surface free energy of galena depends on its degree of oxidation and arise mainly from London's and acid-base intermolecular interactions. It was also found that values of the dispersion and non-dispersion components of galena surface free energy determined from the contact angle assuming that a film is present around the water and diiodomethane drops, are close to those obtained from adsorption isotherms ofn-octane andn-propanol.