Abstract: The nonionic surfactant sorbitan oleate(1.3)polyoxyethylene ether was synthesized by using a two-step synthesis method.The surface tension and contact angle on SiO₂ particle surface were measured through the Washburn equation to explore the floatability of silica with a mixed solution of sodium oleate and naphthenate at room temperature.The results show that adding Tween-1.3can increase the critical micelle concentration of sodium oleate and the dispersion of mixed solution significantly,which makes the reverse flotation temperature of hematite reduced from 40℃to 23℃.An iron concentrate with Fe grade of 68.63% and Fe recovery of 90.20% can be obtained on optimum reagent condition through one roughingone refining-three scavengings closed-circuit flowsheet.