Abstract: GP193G75,a newly developed refined tall oil supplied by Georgia-Pacific Chemicals LLC,was investigated as a collector for the flotation of phosphate ore from CF Industries' phosphate rock mine in Florida.Its adsorption on the surface of hydroxyapatite was characterized using a quartz crystal microbalance with dissipation(QCM-D) in comparison with sodium oleate and the plant collector of CF Industries(PR1) which was the mixed crude tall oil fatty acid.The effect of the new collector GP193G75 on phosphate flotation was evaluated at different process parameters such as collector dosage,pH values,diesel dosage and flotation time.The results show that the highest recovery of 91.7% is achieved when the refined tall oil is used at the dosage of 0.45kg·t^-1 at pH 10 with a 9∶8 mass ratio of fatty acid to diesel.The data of QCM-D show the similar adsorption process with GP193G75 and sodium oleate,and GP193G75 adsorbs on hydroxyapatite more readily and quickly than sodium oleate.In comparison with PR1,GP193G75 forms a higher adsorption density and a more rigid adsorption layer,which produce a stronger hydrophobicity and a better flotation performance.