Abstract: Due to its large specific surface area， high surface energy， small volume and small mass， the fine-grained ore causes non-selective agglomeration among particles， which deteriorates the flotation environment and makes it difficult to obtain favourable indicators for conventional froth flotation. For East Anshan Sintering Plant the carrier flotation test study on Magnetic Plant samples， including gravity concentrate fine undersize as carrier minerals， mixed magnetic concentrate as adhesion minerals， the experimental results show that the pH value of 11.50， the flotation temperature of 35.0 ℃， CaO dosage of 700 g/t， starch dosage of 1 200 g/t， TD-Ⅱdosage of 500 g/t， and TD-Ⅱdosage of 250 g/t for cleaning， after the reverse flotation closed process of one roughing， one cleaning， three scavenging， the carrier flotation index was improved compared with the conventional flotation significantly， and the concentrate grade increment was improved by 1.12 percentage points. The particle size analysis of the product showed that the content of -20 μm in the carrier flotation concentrate product was reduced significantly， the cumulative volume curve peak showed a tendency to move to the coarse grain level， and the strength decreased， the apparent particle size of the mineral increased， and the flotation environment was optimized.

Key words: Fine-grained iron ore, Reverse flotation, Carrier Flotation, Particle size analysis