Dispersion-flocculation studies on hematite-clay systems

Studies have been made on the separability of clay minerals such as kaolinite, illite and montmorillonite from hematite in dispersant-starch flocculant systems. The grossly different dispersibility of hematite from that of clay minerals aided separation by selective dispersion and flocculation. Moderate success has been achieved with a selectivity index nearing 4.0 (average recovery values around 80%).The studies have been extended to hematite recovery and clay rejection from the slimes of the Barsua iron ore washing plant owned by Rourkela Steel Plant, India. Limited success achieved in the starch selective flocculation method has been attributed to the difficulties associated with fine grain size, clay mineraloty and liberation.The ore exhibits the phenomenon of differential grinding. Hematite-rich coarser particles in the slime can be separated by differential settling in dispersant systems followed by selective flocculation in low-starch systems.