After the magnetite, hematite and goethite are the most important iron ore. A single process, known as selective flocculation and dispersion, has been successfully implemented at a plant scale for the beneficiation of hematite ore. The process is driven by surface chemistry modifications that enhance the separation of the hematite from its gangue minerals. Flocculating agent that are used widely in the processing. However, their use often give rise to environmental and health problems. Because these are not readily biodegradable and some of them are neurotoxic. Thus, the development of a safe biodegradable flocculant that will minimize environmental and health risk is urgently required. In recent years, the used of bio-polymers produced by microorganisms and its metabolite has been investigated. In this sudy, Cells and metabolite of Bacillus licheniformis were applied in the bioflocculation of hematite and goethite A full factorial design was employed to study the effects of bio-reagent, pH and solid weight on the settling process. It was indicated that exopolysaccharide shows a better sedimentation rather than the rest. It was concluded that high level of settling occurred at pH 5-7, were in agreement with the trend of bioflocculant adsorption. All the tested bioreagents showed acceptable flocculating capabilities that were largely dependent on electrostatic forces. Finally Bacillus licheniformis were applied as bioflocculants to selectively remove kaolin and silica from hematite and goethite. Polysaccharide component of the metabolite showed the best capability to remove about 50 to 68% of iron impurities at pH 7. Therefore, the extracellular polysaccharide of the bacterium was introduced as an effective and promising flocculant for kaolin/ silica separation from iron oxide.
