Upgrading of Koton Karfe Iron Ore through Roasting and Leaching

Volume 2 - Issue 2

Adeosun AS¹, Abere DV²*, Akinwole IE¹, Ojo SA³, Otebe S⁴, Uzuh FD², Abubakar UBS² and Goyol CG²

Received: November 13, 2019;   Published: November 22, 2019

DOI: 10.32474/MAMS.2018.02.000134

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Abstract

This study investigated the de-phosphorization, de-sulphurization and de-mineralization of roasted pre-treated Koton-karfe iron ore by atmospheric organic acid leaching with the aim of upgrading the iron ore to concentrate and super-concentrate for use in indirect and direct iron making processes, respectively. The work involved chemical and mineralogical characterization, roasting pre-treatment and particle size analysis of the iron ore as-received, as-roasted and as-leached. The ore as-received and as-roasted at 750˚C was subjected to factorial design based atmospheric organic acid leaching at fine and coarse particle sizes of 75 and 475μm; low and high contact times of 30 and 90 minutes were observed. Operation carried out at concentrations of 0.2 and 1.0 M at temperatures of 30 and 90˚C. The leaching was carried out in single and multistage. XRF analyses were carried out on all the samples. The leaching sequence of H2O-HCOOH-H2O was found to produce the highest grade of the iron ore concentrate in the multistage leaching. The results of the XRF analysis showed that as-received Koton-karfe iron ore contains; 43.45, 0.0246, 0.098 weight % of iron, phosphorus, Sulphur respectively. The as-roasted Koton-karfe iron ore contains; 46.91, 0.012, 0.05 weight % of iron, phosphorus, Sulphur, respectively and roasted-leached with formic acid in multistage contains; 67.89, 0.00123, 0.001 weight % of iron, phosphorus, and Sulphur. The results obtained indicates that the % purity of the iron content in the roasted-leached Kotonkarfe iron ore was increased by 56.25 weight %, while the deleterious phosphorous, Sulphur and silica contents were drastically reduced by 95.00, 98.98 and 80.85 weight %, respectively. The iron content of the roasted-leached sample of 67.89 weight % satisfy the specifications of 63 and 67% Fe minimum content for iron ores for both in-direct and direct iron making processes, respectively. The research has thus shown that hydrometallurgical leaching process is an efficient beneficiation route for the separation of iron oxide from other gangue oxides in the Koton-karfe iron ore. It can also be deduced that the roasting process significantly enhanced the leaching removal of sulphur, phosphorus and other gangue materials in the ore. Thus, the pre-roasting leaching process has significantly reduced the undesirable phosphorus, sulphur and silica content in the ore and increased the iron metal value in the ore rendering it suitable for both the blast furnace process in Ajaokuta and the Midrex reduction operation at Aladja.

Keywords: Leaching; sulphur; phosphorus; acid, iron, roasted

Abstract| Introduction| Materials and Methods| Results and Discussion| Conclusion| References|