Abstract: In order to find out the root cause of high Al2O3 content in Chengchao iron concentrate， the process mineralogy characteristics of iron concentrate are systematically studied by means of multi-ele⁃ ment analysis，particle size screening，iron phase analysis，electron probe，scanning electron microscope and element balance calculation. The occurrence law of aluminum and the microscopic characteristics of main aluminum-containing minerals are clarified.The results show that the TFe content of the iron concen⁃ trate is 64.790%，and the Al2O3 content is 1.710%. The Al element is mainly present in magnetite，chlo⁃ rite and mica. The Al element is isomorphically replaced in magnetite，and chlorite and mica are often as⁃ sociated or wrapped with magnetite in the form of fine particles，which becomes a mineralogical difficulty in reducing aluminum，and provides basic mineralogical data support for the optimization of the aluminum reduction and upgrading process of the iron concentrate.

Key words: iron concentrate, process mineralogy, magnetite, aluminum-containing mineral, occur? rence law