Selective hydrophobic flocculation in apatite-hematite system by sodium oleate

The flocculation and selective flocculation behaviour of apatite-hematite system have been studied with sodium oleate as the flocculant and sodium silicate and sodium pyrophosphate as the dispersants. The results show that sodium oleate is an effective flocculant of apatite over a wide range of pH, but a dispersant in alkaline media and a flocculant in neutral to acidic media for hematite. Selective flocculation of the minerals has been achieved from their mixture. Better selectivity has been obtained from their mixture. Better selectivity has been obtained from the mixture with a higher apatite to hematite ratio. The mechanisms involved in the selective flocculation have been discussed in terms of adsorption, dimerization and precipitation of oleate.