Abstract: The original beneficiation process in Donganshan dressing plant that siderite was treated by direct flotation and hematite (magnetite) and quartz were separated by reverse flotation could not adapt to the production increasing of siderite ore. Taking NM-1 as the dispersant of micro-fine siderite，research on technical conditions of reverse flotation for magnetic coarse concentrate was carried out. The results showed that iron concentrate with Fe grade 66.37% and Fe recovery of 75.00% was obtained by the single reverse flotation process of one roughing-two cleanings-one scavenging and middlings back to the flow-sheet in turn,using NM-1 as dispersant. Optimized process was even more concise and improved the economic and technical indicators，obtaining the Fe concentrate grade deceased by 1.47% and Fe recovery increased 5.53%.

Key words: Siderite, Magnetic coarse concentrate, Dispersants NM-1, Iron increase and impurity reduction