Abstract: Beneficiation experiment is carried out on a molybdenum ore in Liaoning province based on the process mineralogy research at the aim of high efficiently developing the molybdenum resources.The results show that，molybdenite granular is fine imbedded in the ore with molybdenum grade of 0.217%，and the valuable elements mainly exist in form of pyrite and magnetite.Molybdenum flotation of two roughing-two scavenging is carried out after grinding at the fineness of 67% -200 mesh.Molybdenum rough concentrate is reground at the fineness of 92.10% -400 mesh，and then molybdenum concentrate with molybdenum grade of 49.43% and recovery of 91.11%，and sulfur concentrate with sulfur grade of 53.00% and recovery of 73.03% are received separately through six molybdenum cleaning，and sulfur concentration from flotation tailings of molybdenum scavenging by one roughing-two cleaning-one scavenging，and middles back to the flowsheet.Both molybdenum and sulfur is ideally recovered，so this closed circuit process is reasonable for development and utilization of the ore.

Key words: Molybdenite, Grinding, Re-grinding of the rough concentrate, Floatation