Abstract: Iron minerals of an iron ore from Hunan are mainly magnetite and secondly hematite,and 12.12% of the iron exists in the form of silicate minerals.Among these,magnetite is middle or fine disseminated and hematite is disseminated in extremely microgranular.It is hard to achieve good separation index.According to the ore property,the process of stage grinding-low intensity magnetic separation(LIMS)-high intensity magnetic separation(HIMS)-selective flocculation desliming-reverse flotation was conducted.First,magnetite was concentrated through LIMS at coarse grinding fineness of 65.87% passing 0.075 mm.Second,hematite was enriched from tailings of LIMS by HIMS to discard gangue minerals.Third,two stage grinding (primary grinding at 0.038 mm accounted for 96.56%,second grinding at 98.93% passing 0.019 mm) and four stage selective flocculation desliming operation were adopted to deal with HIMS concentrate.Forth,reverse flotation of one roughing-one cleaning-four scavenging operation on underflow from desliming were made.Mixed iron concentrate with yield rate of 32.33%,iron grade of 63.55% and recovery of 71.34% was obtained,which provide technical basis for rational development and utilization of the ore.

Key words: Micro-fine disseminated hematite, Stage grinding, Magnetic separation, Magnetic seeds, Selective flocculation desliming, Reverse flotation