Abstract: There is a molybdenum deposit in Henan,ore extracted mainly belong to hornfels-type,including diopside-plagioclase hornfels-type,felsic hornfels-type,and biotite-quartz hornfels-type,molybdenum grade of each type is much similar,with same molybdenum sulfide content.Molybdenite exists in form of lamellar distributed among different minerals in diopside-plagioclase hornfels-type and felsic hornfels-type molybdenum ore；Molybdenite present mainly in acicular and irregular shaped,revealed in layers along the ore breakage,with fine grain size.Single reagent system and grinding fineness was used originally in on-site process,and cannot obtain good molybdenum recovery index.To improve separation index,grinding fineness and reagent system for each type of the ore was optimized based on the ore property analysis.One roughing-one cleaning-one scavenging closed circuit flotation process was conducted using the optimized test conditions.Results show that molybdenite is fine distributed in biotite-quartz hornfels-type molybdenum ore,to achieve liberation fine grinding is needed,and clay mineral content will increase after fine grinding,surface property discrepancy of different minerals become smaller,results in conglutination in each particles,and molybdenum grade of concentrate become lower；molybdenite mainly exists in form of schistose in diopside-plagioclase hornfels-type and felsic hornfels-type ore,and with good floatability,coarsely disseminated and easily to be liberated,the separation index is good.When dealing with the three kinds of ore,effects of ore properties to flotation should be considerate,and adjust the grinding fineness and agent system in time to increase the mineral processing index and improve economic benefit.

Key words: Process mineralogy, Hornfels-type molybdenum ores, Flotation