2019 Volume 59 Issue 6 Pages 1145-1151
Indian iron ore mining industry disposes large amount of ultra fines containing high gangue minerals, thereby lead to loss of iron values and environmental pollution. Selective flocculation studies have been thought of for beneficiation of ultra fines. Response of different types of starches to iron ore ultra fines generated by the hydro-cyclone in Joda Iron Ore Washing Plants, Orissa, India has been studied. The starches used are: (i) maize starch (MS), (ii) potato starch (PS) and (iii) causticized potato starch (CPS). The order of selectivity as flocculant towards iron bearing minerals is observed as MS<PS<CPS. This can be attributed to the different C-H chain morphology of the starches. MS has more amylopectin than PS. Amylopectin adsorbed strongly onto all oxides minerals as carbonyl groups attached to C-2 and C-3 atoms of starch form surface complex with surface atom of all oxide minerals whereas amylose has a more adsorption tendency to hematite only. Amylose has less number of end groups than amylopectin, thus exhibiting lesser adsorption density than amylopectin. The selective adsorption characteristics of PS to hematite further improves by modification. Iron content and the iron recovery of the concentrate depend on flocculant dosage as well as settling time. A good concentrate is obtained suitable for pellet feed with Fe content in the concentrate increased from 57.8 mass% to 66.3 mass% and with an iron recovery of 66.5% by this process using CPS as a flocculating agent under optimized conditions. The tailing generated is suitable for building materials like tiles.