Particle aggregation characteristics of hematite-quartz mixture with addition of sodium oleate

In the flotation of finely disseminated iron ores, fine hematite and gangue minerals (mainly quartz) always co-exist in the pulp, their higher interface energies would cause complex interfacial interactions and aggregations. Thus, particle aggregation characteristics in hematite-quartz systems with sodium oleate (NaOL) were studied in this research. The focused beam reflectance measurement (FBRM) and Zeta potential distribution analyses revealed that quartz and hematite particles formed hetero-aggregates at pH 5.0–7.0, while NaOL would weaken the hetero-aggregation by inducing the aggregate formation of hematite particles. The adsorption and contact angle tests indicated that hetero-aggregation inhibition could be attributed to oleate ion (OL−) adsorption onto hematite surfaces, which changed the surface charge and hydrophobic characteristics. Theoretical calculations demonstrated that the hydrophobic interactions among hematite particles, rendered hydrophobic by NaOL, were the main cause of hematite particles forming large aggregates.