Abstract: Because the content of Al2O3 in the finished pellets of Chengchao Mining Company exceeded the standard,it affected the sales of finished pellets.In order to reduce the Al2O3 content of the iron concentrate,grindinglow intensity magnetic separation process is performed based on the mineralogy analysis.Results show that the presence of aggregated fine magnetite and aluminumbearing minerals is the main reason for Al2O3 content out of limit.The Al2O3 content of iron concentrate can be reduced via increasing the grinding fineness and reducing of the intensity of magnetic field.1.06% of Al2O3 content was achieved when the intensity of magnetic field was controlled at 105.89 kA/m and the grinding finenessof -0.076 mm accounted for 80%,with an iron recovery of 97.27%.Moreover,when the intensity of magnetic field was 113.85 kA/m with the grinding fineness of -0.076 mm for 85%,the Al2O3 content was 102% and iron recovery was 9798%.

Key words: Iron concentrate, Al2O3 content, Grinding degree, Low intensity magnetic separation, Mineralogy process