Selective Flocculation of Banded Hematite Quartzite (BHQ) Ores

The recovery of fine hematite particles from banded hematite quartzite (BHQ) ore with potato starch has been investigated using selective flocculation. Microscopic features, coupled with x-ray diffraction (XRD), and Fourier transforms infrared (FTIR) spectroscopic data provide evidences for adsorption of starch molecules on hematite surface. The starch molecules show good selectivity for hematite particles in the pH range of 8.5-9.5 and in the reagent concentration range of 20-40 mg/l. The Scanning electron microscope (SEM) studies show that flocs of hematite particles are larger and appear to be denser than that of quartz. Initial results with 1:1 hematite-quartz mixture indicated that it is possible to achieve an iron concentrate of 64.5% Fe with 92.0% of iron recovery from a feed of 34% Fe. However under optical conditions of pH and reagent concentration, the BHQ ore could be upgraded from an initial grade of 38.9% Fe to 57.2% Fe with 71% recovery. The overall results indicate that separation of very fine grained hematite present in the BHQ iron ore is feasible by selective flocculation.