Research on the Flotation Separation of Fine−grained Hematite and Quartz by Combined Cation−anion Collectors

The influence of four anionic collectors, namely sodium dodecyl sulfate (SDS), sodium lauryl sulfate (SLS), sodium dodecyl benzene sulfonate (SDBS), and sodium oleate (NaOL), in combination with the cationic collector dodecylamine (DDA), on the flotation separation of fine−grained (−18 μm) hematite and quartz was investigated. Single mineral experiments indicated that each of the four anionic collectors in combination with DDA reduced the flotation recovery of hematite in the foam product compared to DDA alone, thus favoring a reduction in the depressant dosage for hematite. When DDA was combined with anionic collectors, the order of separation effectiveness for fine−grained hematite and quartz was SDS > NaOL > SLS/SDBS. Among them, the DDA+SDS combinated collectors exhibited the best performance under certain mass ratio conditions. Under the optimal flotation conditions (pH=7, collector dosage of 20 mg/L, m(DDA)∶m(SDS)=2∶1, depressant dosage of 20 mg/L), the quartz recovery in the foam product reached 91.05%, while the hematite recovery was only 6.7%, facilitating hematite reverse flotation. Artificial mixed mineral flotation experiments showed that the DDA+SDS combinated collectors (m(DDA)∶m(SDS)=2∶1) achieved a concentrate with Fe grade of 45.7% and a recovery rate of 87.0%. Compared to DDA alone, this represented an increase of 1.7 and 18.6 percentage points, respectively, contributing to an improved separation efficiency of hematite and quartz. DDA+SDS can be considered an excellent anionic−cationic collectors for the flotation separation of fine−grained hematite and quartz.