Selective Flocculation of Chromite Tailings

Odisha state is the major reserve of the chromite ore. Due to the extensive applications, high-grade chromite ore is getting depleted day by day. Now it is a challenge for the industry to utilize these low-grade ores and tailings. Several attempts were taken to upgrade the low-grade chrome ores and tailings using different gravity separation methods, magnetic separation methods, flotation, etc. But all the techniques have limitations for handling these ultra-fine chrome ores. Selective flocculation process can be one alternative method for upgrading the ultrafine chromite (< 37 mu m). Mineralogical analysis reveals that ultrafine chromite tailing (< 37 mu m) is enriched with ferruginous phase. Causticized starch of wheat origin was identified and used for flocculating. Selective flocculation performance due to change in different operating parameters such as dispersant dose, pH and flocculant dose was studied. Result shows that Cr2O3 (%) increases to 31.08 (%) with Cr/Fe > 1 from a feed grade of 16.36 (%) Cr2O3 with 0.36 Cr/Fe ratio. FTIR analysis reflects selective adsorption of the flocculant mineral surface.