Coal Slurries Desulfurization by Flotation Using Thiophilic Bacteria for Pyrite Depression†

Zeky, M. El; Attia, Yosry A.

doi:10.1080/07349348708945554

Cited by 35 publications

(10 citation statements)

References 8 publications

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“…Zeky and Attia also reported that the pyritic sulfur in coal was rejected by about 90% by bacterial treatment using T. ferrooxidans for 5-10 min prior to flotation. 22 It had been considered that pyrite oxidation by T. ferrooxidans might induce floatability suppression by changing the surface property from hydrophobic to hydrophilic. The change by oxidation might occur at a few molecular layer of pyrite surface, so that the microbial effect appears in a short time.2 As this speculative explanation has been widely accepted, the mechanism of pyrite suppression by the bacterium has not been investigated in depth.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of microbial flotation using Thiobacillus ferrooxidans for pyrite suppression

Ohmura

Kitamura

Saiki

1993

Biotech & Bioengineering

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Microbial desulfurization might be developed as a new process for the removal of pyritic sulfur from coal slurries such as coal-water mixture (CWM). An application of iron-oxidizing bacterium Thiobacillus ferrooxidans to flotation would shorten the periods of the microbial removal of pyrite from some weeks by leaching methods to a few minutes. The floatability of pyrite in flotation was mainly reduced by T. ferrooxidans itself rather than by other microbial substances in bacterial culture as additive of flotation liquor. Floatability was suppressed within a few seconds by bacterial contact. The suppression was proportional to increasing the number of cells adhering to the pyrite surface. A linear relationship was observed between bacterial adhesion and the suppression of floatability. If 25% of the total pyrite surface area were covered with the bacteria, pyrite floatability would be completely depressed. Bacteria that lost their iron-oxidizing activities by sodium cyanide treatment were also able to adhere to pyrite and reduced pyrite floatability as much as normal bacteria did. Thiobacillus ferrooxidans ATCC 23270, T-1, 9, and 11, which had different iron-oxidizing abilities, suppressed floatability to similar-levels. The oxidizing ability of bacteria did not influence the suppressing effect. These results showed the mechanism of the suppression of pyrite floatability by bacteria. Quick bacterial adhesion to pyrite induced floatability suppression by changing the surface property from hydrophobic to hydrophilic. The quick adhesion of the bacterium was the novel function which worked to change the surface property of pyrite to remove it from Coal. 0 1993 John Wiley & Sons, Inc.

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Section: Introductionmentioning

confidence: 99%

Mechanism of microbial flotation using Thiobacillus ferrooxidans for pyrite suppression

Ohmura

Kitamura

Saiki

1993

Biotech & Bioengineering

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“…This bacterium has also been used in removing pyrite from mixtures of sulfide minerals [62][63][64][65]. Acidithiobacillus ferrooxidans have frequently been used as an excellent pyrite depressant in coal flotation [66][67][68][69]. Bacillus polymyxa was used in the separation of sulfide minerals [70], iron ore flotation [71], for pyrite separation from oxide gangue minerals [72], and in the separation of galena from chalcopyrite [73].…”

Section: Biofrothersmentioning

confidence: 99%

Flotation Frothers: Review of Their Classifications, Properties and Preparation

Khoshdast¹

2011

TOMPJ

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Abstract:The importance of frothers in flotation is widely acknowledged, particularly in terms of their role with respect to bubble size, and the stability and mobility of the froth phase. These factors play a significant role in the kinetic viability of the process, and the overall recovery and the grade that can be achieved from a flotation cell or circuit. About 60 years ago, Wrobel [1] presented a comprehensive review of flotation frothers, their action, properties and structures. However, during recent six decades flotation reagent technology has undergone considerable evolutions and innovations. The aim of the present review is to provide an updated, comprehensive database comprising recent developments in flotation frother technology as well as some historical aspects. Different types of flotation frothers are discussed regarding to their classifications, properties, and preparation methods. New classification schemes have been suggested in parallel with introducing new characterization criteria. New classes of frothers are actually conventional frothers modified by incorporating certain functional "group" or "atoms" into their molecular structure. Like particle surface modifiers, frothers are also influenced by biotechnology, leading to introducing a new class of frothers named as "biofrothers".

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“…The biomodification of salt-type mineral surfaces by Aspergillus niger has been studied by Sadowski and Golab (5). Preconditioning with various microorganisms such as Thiobacillus ferrooxidans is known to cause depression of pyrite in coal flotation (6,7). Similarly, bacterial conditioning with T. ferrooxidans resulted in the depression of galena while sphalerite was floated (8,9).…”

Section: Introductionmentioning

confidence: 98%