Abstract: As the iron grade of the gravity concentrate becomes lower in a concentration plant in Liaoning Province， which would not be used as the final concentrate product to integrate into the comprehensive concentrate. Process mineralogy of gravity concentrate is conducted to study in detail from the aspects of chemical composition， element occurrence state， mineral composition， inter-mineral intrusion relationship and continuous relationship， in order to provide guidance for the improvement of the process flow. The results show that the iron grade is 60.62%， and iron in the gravity concentrate is mainly found in hematite and magnetite， and the main gangue mineral is quartz. Iron is mainly distributed in the -0.074 mm grain size. In this grain size the rate of iron distribution is as high as 84.47%， the TFe grade is 64.52%， and iron ore and gangue in gravity concentrate can only be separated by fine grinding. In the combination of useful minerals and gangue， the main combination form is the combination of hematite and gangue， followed by the combination form is the combination of magnetite， hematite and gangue minerals. It was found that the monomer dissociation degree of hematite and magnetite in the sample increased rapidly with the grain size becoming finer. Especially in the -0.045 mm grain size products， the majority of hematite and magnetite particles completed the monomer dissociation. Hematite and magnetite are mainly imbedded with medium and fine grain size. The gangue content in the medium grain size sample is still relatively high， and the content of fine hematite and magnetite is relatively high. Iron mainly occurs in the -0.074 mm grain size. It is suggested that the fine sieving gradation-carrier flotation process is used for experimental research. That is， the gravity concentrate， the product on the screen is returned for re-grinding， the product under the screen enters the flotation and carries fine-grained magnetic separation concentrate to complete recovery.

Key words: Gravity concentrate, Mineralogy, Mineral composition, Dissemination characteristics, Dissociation degree