Flotation of silicated gangue iron ores: Mechanism and effect of starch

Hematite floatability is always lower than that of quartz under the same physico-chemical conditions. Indeed, up to pH > 9, the presence of molecular amine in solution is detrimental to hematite flotation. adsorbs specifically on both minerals (more on quartz than on hematite). However, starch adsorbed on quartz will desorb in alkaline medium in the presence of alkylammonium salt according to the collector concentration and pH (competing adsorption). This is not the case for hematite for which the starch-mineral affinity is stronger than that of the quartz.