Abstract: Indicators of reverse flotation concentrate from mixed magnetic concentrate from a Iron Mine of Hebei province,are not satisfactory,mainly due to inadequate monomer dissociation and unsatisfactory reverse flotation performance.On-site mixed magnetic iron concentrate was treated by reverse flotation in order to increase effect of iron increase and silicon reduction operation.The results showed that iron concentrate with iron grade of 63.98% and iron recovery of 81.60% was gaind at the grinding fineness of 80.48% passing 0.043 mm through the process of one roughing,one cleaning,two scavenging,and middles back to the flowsheet in turn process.Compared with the on-site process,the new process increases regrinding operation of the mixed magnetic concentrate,decreases the number for cleaning and scavenging by one time.By this method,iron grade and iron recovery are increased by 1.70 and 11.01 percentage points respectivley.The beneficiation indicators were improved significantly.

Key words: Mixed magnetic concentrate, Intergrowth, Grinding, Reverse flotation, Process optimization