Mycrobially Induced Processing of Mineral Fines

Microorganisms such as Bacillus polymyxa which occur indigenously associated with several ore deposits, bring about significant surface chemical changes on interacted minerals such as hematite, corundum,calcite, quartz and kaolinite. Bacterial interaction rendered quartz and kaolinite surfaces hydrophobic, while hematite, corundum and calcite surfaces became more hydrophilic. Biotrearment of mineral mixtures containing the above minerals was found to result in selective _flocculation and selective flotation. It is shown that selective removal of silica and alumina from iron ores and bauxite can be brought about by biological processes.Mechanisms behind such microbially induced beneficiation processes are illustrated with res-pect to processing of fine particles

Interaction of Bacillus polymyxa with some oxide minerals with reference to mineral beneficiation and environmental control

Interaction of Bacillus polymyxa with calcite, hematite, corundum and quartz resulted in significant surface chemical changes not only of the cells but also in the minerals. Both the cell surfaces as well as quartz particles were rendered more hydrophobic after mutual interaction, whilst the rest of the minerals exhibited enhanced hydrophilicity after interaction with the bacteria. The bacteria were also observed to be capable of dissolving calcite, hematite and corundum and biosorbing the dissolved metal ions to varying extents. An excess of polysaccharides could be observed on biotreated calcite, hematite and corundum while the predominance of a protein-based metabolic product was evident on quartz surfaces. The utility of bioprocessing in the beneficiation of the above minerals through bioflotation and bioflocculation is demonstrated. (C) 1997 Elsevier Science Ltd

Role of bacterial interaction and bioreagents in iron ore flotation

Interaction between Paenibacillus polymyxa and iron ore minerals such as hematite, corundum, calcite, quartz and kaolinite brought about significant surface chemical changes on all the minerals. Quartz and kaolinite were rendered more hydrophobic, while the other three minerals became more hydrophilic after bacterial interaction. Predominance of bacterial polysaccharides on interacted hematite, corundum and calcite and of proteins on quartz and kaolinite was responsible for the surface chemical changes. The bacterial strains could be preadapted to different mineral substrates. Corundum-adapted strains were seen to secrete mineral-specific proteins which could be used to separate alumina from iron ores. The utility of bioprocessing in the beneficiation of iron ores for removal of silica and alumina is demonstrated

Studies on interaction of Paenibacillus polymyxa with iron ore minerals in relation to beneficiation

Interaction between Paenibacillus polymyxa with minerals such as hematite, corundum, quartz and kaolinite brought about significant surface chemical changes on all the minerals. Quartz and kaolinite were rendered more hydrophobic, while hematite and corundum, became more hydrophilic after biotreatment. The predominance of bacterial polysaccharides on interacted hematite and corundum and of proteins on quartz and kaolinite was responsible for the above surface-chemical changes. Bio-pretreatment of the above iron ore mineral mixtures resulted in the selective separation of silica and alumina from iron oxide, through bioflotation and bioflocculation. The utility of bioprocessing in the beneficiation of iron ores is demonstrated

Studies on interaction of Paenibacillus polymyxa with iron ore minerals in relation to beneficiation

Interaction between Paenibacillus polymyxa with minerals such as hematite, corundum, quartz and kaolinite brought about significant surface chemical changes on all the minerals. Quartz and kaolinite were rendered more hydrophobic, while hematite and corundum, became more hydrophilic after biotreatment. The predominance of bacterial polysaccharides on interacted hematite and corundum and of proteins on quartz and kaolinite was responsible for the above surface-chemical changes. Bio-pretreatment of the above iron ore mineral mixtures resulted in the selective separation of silica and alumina from iron oxide, through bioflotation and bioflocculation. The utility of bioprocessing in the beneficiation of iron ores is demonstrated

Biodegradation of some organic flotation reagents by Bacillus polymyxa

The soil bacterium Bacillus polymyxa is shown to effectively remove organic flotation collectors such as dodecyl amine, diamine, sodium isopropyl xanthate, and sodium oleate from alkaline solutions. Adsorption and bacterial growth studies indicated enhanced surface affinity of the amine collectors toward the bacterial cells. All the above organic reagents could be efficiently removed from alkaline solutions through bacterial interaction. Ultraviolet (UV)-visible and Fourier transform infrared (FTIR) spectra during biodegradation of these reagents revealed the stages in biodegradation. Possible mechanisms are outlined