By Enebe, Matthew Chekwube
In this study, a bacterial isolate tentatively identified as Bacillus subtilis, obtained from a Nigerian iron ore sample was evaluated for its ability to beneficiate the ore under aerated (shake-flask) and static conditions with variations in inoculum sizes (0 ml, 0.5 ml, 2 ml, or 5 ml of standardized inoculum), ore grain sizes (0.2 mm, 0.4 mm, 0.6 mm, or 0.8 mm) and initial pH (2.5, 7, or 12). The iron ore which was obtained from Itakpe quarry site in Kogi State had the following composition: iron 36%, phosphorus 0.95 %, sulphur 0.03 % and other materials 62.02 %. The study was organized in two phases with each phase lasting for eight weeks. Phase one experiment was conducted in shake-flasks while phase two took place under static conditions. In each of these studies, the effects of varying levels of inoculum, ore grain size and medium pH on the ability of the organism to upgrade the iron metal (converting it from ferric sulphate to ferrous sulphate) as well as mobilize phosphorus and sulphur which are deleterious inclusions in the ore were assessed. A total of sixty-six (66) (33 for each phase) study samples containing both the controls and variations of the test parameters were used with each being conducted in triplicate. Results obtained showed that aeration significantly (p