DEPHOSPHORIZATION OF KOTON-KARFE IRON ORE BY THERMAL TREATMENT AND CHEMICAL LEACHING

Abstract

Research work has been undertaken to dephosphorize Koton-Karfe iron ore, KogiState, Nigeria by thermal treatment and chemical leaching. The -180 +125µm size fraction of the ore was calcined at 700, 800 and 900oC, then characterized using X-ray fluorescence (XRF) and X-ray diffractometer (XRD) analysis. The calcined ore was leached with Citric, Hydrochloric and Sulphuric acids at the optimum conditions initially established. The results reveal that calcination of the ore transformed the major iron bearing mineral goethite initially in the ore to hematite and released the phosphorus initially in solid solution with the goethite. Leaching of the calcined ore revealed that the highest dephosphorization was obtained with the ore calcined at 900oC at the rate of73.51%, 61.03% and 35.14% for sulphuric, hydrochloric and citric acids respectively. The ICP-OES results reveal minimal loss of iron to the leach solution. This confirms that Sulphuric acid is the better leaching agent of the acids used and its pH values show that the leach liquor can be treated and recycled.