A STUDY OF THE FLOCCULATION OF PURE GOETHITE, QUARTZ, AND KAOLINITE AND THE SELECTIVE FLOCCULATION OF AGBAJA IRON ORE PART II. FLOCCULATION OF PURE GOETHITE, QUARTZ, AND KAOLINITE WITH CASSAVA STARCH

ABSTRACT

A study of the flocculation of pure goethite, quartz and kaolinite with cassava starch in the presence of Na2Si03 and KF has been undertaken. The results show that goethite is fully dispersed in a goethite-quartz mixture under these conditions and that optimum flocculation of goethite occurs at pH 7.5 with 50 ppm cassava starch concentration. Higher recovery of goethite at lower potassium fluoride concentration (20 ppm) was observed. The grade of the concentrate, however, was observed to be higher at higher KF concentrations with a corresponding decrease in recovery. Selective flocculation of goethite is probably due to stabilization of quartz in the presence of Na₂Si0₃ caused by the adsorption of SiO(OH) ₃ on the particle surface, making subsequent adsorption of flocculant on the goethite surface possible. Potassium fluoride (KF) prevents quartz and kaolinite activation, thus promoting selective flocculation of iron-bearing particles.