Abstract: The process mineralogy characteristic such as chemical multi-element,minerals composition,structure,chemical composition and dissemination of limonite,Fe occurrence for a limonite ore from Indonesia were detected.Magnetic parameter tests including grinding fineness,strength of the magnetic field,magnetic medium size and types were also completed.Mineralogical factors that content of silicon and sulfur in iron concentrate is difficult to reduce are probed in the further research.The results showed that limonite is the main iron mineral in the sample,and main gangue minerals are quartz and kaolin.Mainly structures are in concentric rings and biological texture and the grade of impurity substances silicon,aluminum and sulfur is a little relatively high.The SSS-II type magnetic separator were used to separate the limonite ore assaying 51.45% Fe,and the final iron concentrate assaying 54.17% Fe at the recovery of 88.38%.It is difficult to effectively reduce the content of silicon and sulfur in limonite by physical separation method mainly due to its regular distribution