Abstract: Flotation behavior of ultrafine hematite in hydroximic acid and sodium hydroximic system was studied through monomineral flotation experiments. The results showed that under normal temperature and natural pH，two kinds of collectors have weakly collecting ability with the iron recovery rate of only 44.00% and 44.00% respectively; Heating or adjusting pH has a less or negative effect in improving hydroximic acid flotation behavior，but can increase iron recovery of ultrafine hematite by 10.68% and 4.20% respectively with the sodium hydroximic system. In addition，the recovery will be increased significantly by continually stirring for a period after medication. Flotation behavior of ultrafine hematite affecting by five types of regulators (sodium hexametaphosphate，sodium silicate，sodium pyrophosphate，starch，sodium humate) in sodium hydroxamate flotation system were further investigate. The results showed all five kinds of depressors generated high depression effect，and its depressing performance is behaved in the order of sodium pyrophosphate > sodium silicate > sodium hexametaphosphate > starch > sodium humic.

Key words: Ultrafine hematite, Hydroxamate acid, Sodium hydroxamate, Monomineral flotation, Depressor