Abstract:  Aiming at the low grade of iron concentrate ( Fe 52. 35% ) obtained after strong magnetic separation in a limonite concentrator in Yunnan, a detailed experimental study was carried out on the basis otprocess mineralogical research. Under the conditions of catalyst addition amount of 14% , reducing agentaddition amount of 12% , roasting temperature of 1 050 C , and roasting time of 30 minutes , the “enhancereduction roasting-weak magnetic separation"process was used to obtain a concentrate rate of 67.95% anda grade of TFe of 70. 89% ，a good technical index with a recovery rate of 91. 94%.

Key words: limonite, roasting, magnetic separation, combined process of dressing and metallurgy , catalyst