Abstract: In order to improve the separation effect of hematite and limonite in Xishilazi， systematic process mineralogy research was carried out on representative ores through chemical multi-element analysis， XRD analysis， iron phase analysis and so on. The results showed that:①The TFe grade of hematite and limonite in Xishilazi of Qidashan is 27.88%， and the contents of the main gangue component SiO2 is 55.65%. The contents of harmful elements P and S in the ore are 0.006% and 0.005%， respectively. ②The main metallic minerals in the ore are hematite and magnetite， followed by a small amount of limonite and a trace of pyrite. Non-metallic minerals are mainly quartz and a small amount of chlorite and muscovite. The iron in the ores mainly occurs in hematite and limonite， followed by magnetic iron. ③The ore structure consists of automorphic to semi-automorphic crystal structure， pseudomorphic structure， residual structure and metasomatic structure. The ore is mainly in the form of striped structure and disseminated structure. ④Primary hematite and magnetite are mutually embedded in the ore. Magnetite is oxidized and altered to generate pseudo hematite， and secondary hematite is speckled， veined， reticulated and spider-like distribution in the magnetite. Hematite and magnetite are immiscible intergranular particles， and the two are difficult to dissociate from each other and could be recovered together. ⑤Quartz is mainly produced in automorphic granular aggregates， with fine dissemination particle size， and a small amount of fine chlorite and muscoite are embedded between particles. ⑥Magnetite and hematite are mainly distributed in medium grains， and the contents of fine grains is large. The distribution rate bellow 0.038 mm grain size is as high as 20.22%. It is difficult to achieve completely monomer separation and easy to be lost in tailings， causing difficult in recovery.

Key words: processing mineralogical, dissemination characteristics, hematite, magnetite