Selective Attachment of Leptospirillum ferrooxidans for Separation of Chalcopyrite and Pyrite through Bio-Flotation

Bleeze, Belinda; Zhao, Jing; Harmer, Sarah L.

doi:10.3390/min8030086

Cited by 12 publications

(6 citation statements)

References 44 publications

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“…Selective attachment on sulphidic minerals of the ore has been observed for Metallosphaera hakonensis [56] and for bioleaching microorganisms [2]. The bioleaching microorganism Leptospirillum ferrooxidans was preferentially attached to pyrite over chalcopyrite resulting in biofilm formation on pyrite surface, but not on chalcopyrite surface [34]. Leptospirillum ferrooxidans was shown to have a higher affinity to chalcopyrite than to pyrite, which resulted in higher depression of chalcopyrite in flotation and better settling behavior [26].…”

Section: Attachment Of Microorganisms On Mineral Surfacementioning

confidence: 97%

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Review of Potential Microbial Effects on Flotation

2020

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Microorganisms enter the flotation process mainly from intake water and ore material. The diversity and number of microorganisms can vary significantly from mine to mine. In flotation, the conditions including oxygen levels, temperature, and nutrients from ore, intake water, and reagents are often favorable for the microbial growth. The mining industry aims to close the water loops, which is expected to result in the accumulation of microorganisms in the process waters with potential effects on flotation performance. Bioflotation, bioleaching, and bio-oxidation have been studied for decades as tools for concentrating and dissolving minerals. In contrast, there is limited scientific literature or industrial knowledge about microorganisms that naturally inhabit and prevail in minerals processing applications over a wide pH range. Microorganisms affect minerals when they selectively attach to the surfaces, produce extracellular polymeric substances (EPS) and polysaccharides, oxidize or reduce the minerals, change the pH and Eh of the process solution, and degrade organic flotation chemicals. Microorganisms contain different structural components that affect their surface chemistry, charge, and behavior in flotation, but these properties may also change via adaptation and solution conditions. Almost all studies on flotation have focused on chemical and physical parameters, and the role of naturally occurring microorganisms has remained underexplored. Advances in genomics and proteomics offer possibilities to describe not only which microorganisms are present, but also which physiological functions are being exercised. This article reviews the current knowledge of microorganisms in various mineral processes, identifies potential microbe–mineral interactions in flotation, describes the gaps in current knowledge, and concludes with the potential effects of microorganisms on flotation, especially in closed water loops.

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Section: Attachment Of Microorganisms On Mineral Surfacementioning

confidence: 97%

“…The adhesion of Leptospirillum ferrooxidans cells on chalcopyrite and pyrite caused flocculation of both minerals [33]. Acidithiobacillus ferrooxidans had a depressive effect on pyrite [26] and Leptospirillum ferrooxidans on chalcopyrite [34].…”

Section: Sulphur-and Iron-oxidizing or Reducing Microorganismsmentioning

confidence: 99%

Review of Potential Microbial Effects on Flotation

2020

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“…A modified Leptospirillum HH was used for growing L. ferrooxidans [63]. On the other hand, the best separation was obtained when L. ferrooxidans grew on chalcopyrite [73]. The contradictory flotation results between the different studies [63,73] might be due to their different methods of growing L. ferrooxidans.…”

Section: Leptospirillum Ferrooxidansmentioning

confidence: 99%

“…Extracellular polymeric substances (EPS) derived from L. ferrooxidans were found to be more effective than the L. ferrooxidans cultures [73]. Thus, improved chalcopyrite recovery and greater depression of pyrite was achieved with the use of EPS extracted from L. ferrooxidans.…”

Section: Leptospirillum Ferrooxidansmentioning

confidence: 99%

Towards the Biobeneficiation of PGMs: Reviewing the Opportunities

2021

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Conventional beneficiation of the Platinum Group of Metals (PGMs) relies on the use of inorganic chemicals. With the depreciation of high grade deposits, these conventional processes are becoming less economically viable. Furthermore, the use of chemicals has serious negative impacts on the environment. To address the challenges of conventional PGM beneficiation, biobeneficiation has been proposed. In conventional flotation, the flotation behavior of the associated sulphides determines overall PGM recovery. The same principle may also be applied for the bio-beneficiation of PGMs. Therefore, this paper discusses the biobeneficiation behavior of sulphides closely associated with PGMs with the aim of postulating the bio-beneficiation behavior of PGMs associated with the same base metal sulphides. Conventional PGM processes are briefly discussed, as bio-beneficiation of PGMs is governed by similar underlying principles. Potential microorganisms for the biobeneficiation of PGMs are highlighted, as well as the corresponding conditions for their effectiveness. The use of both single cultures and mixed cultures is discussed. Depending on conditions, PGMs associated with pyrite and/or chalcopyrite were projected to be biofloatable with B. polymyxa, P. polymyxa, A. ferrooxidans, L. ferrooxidans, B. pumilus, B. subtilis, halophilic bacteria, Alicyclobacillus ferrooxidans, sulphate reducing bacteria, and mixed cultures of A. ferrooxidans, A. thiooxidans and L. ferrooxidans. Pyrite-associated PGMsare expected to be generally prone to biodepression, whereas chalcopyrite-associated PGMs are expected to be generally recovered as the floatable phase. Sulphate-reducing bacteria were reported to have a dual role on the bioflotation of sulphide ores (flotation and depression), depending on the conditions. Therefore, this type of microorganism may serve as both a depressant or a collector in the recovery of PGMs. Based on the bioflotation response of pyrrhotite to L. ferrooxidans, it is anticipated that pyrrhotite-associated PGMS can be biodepressed using L. ferrooxidans. In terms of bioflocculation, PGMs associated with chalcopyrite may be recovered using L. ferrooxidans, whereas A. ferrooxidans, A. thiooxidans, B. polyxyma and B. subtilis can be used in the bioflocculation of pyrite-associated PGMs. M. phlei can be employed in the reverse bioflocculation of pyrite-associated PGMs. Although no information was found on the biobeneficiation of pentlandite, postulations were made based on other sulphide minerals. It was postulated that biobeneficiation (biodepression and bioflotation) with pentlandite-associated PGMs should be possible using A. ferrooxidans. It is also projected that sulphate-reducing bacteria will be suitable for the bioflotation of PGMs associated with pentlandite. The removal of gangue species such as silicates and chromites associated with PGM concentrates was also discussed. A. ferrooxidans, P. polymyxa and B. mucilaginous are candidates for the removal of gangue species. Furthermore, the need to control process conditions was highlighted. The most suitable conditions for biobeneficiation of the various base metal sulphide minerals associated with PGMs are presented in the paper. Most of the challenges associated with biobeneficiation of PGMs are already common to conventional methods, and the means of circumventing them are already well established. Developments in genetic engineering and the advent of new data science techniques are tools that could make the biobeneficiation of PGMs a possibility.

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“…In 1999, American scholars (Zheng et al, 1999) studied the flotation separation of apatite and dolomite with anionic collector in the presence of Mycobacterium phlei (M. phlei), and found that M. phlei strains can be used as inhibitors of these two minerals, and the inhibitory effect on dolomite is better than that on apatite. Bleeze et al (2018) studied the extracellular polymeric substance (EPS) extracted from Leptospirillum ferrooxidans, grown on chalcopyrite for 48 hours, and polysaccharide-rich EPS selectively attaches to pyrite within 48 h, depressing its floatability and ensuring successful separation with a PIPX collector, resulting in Cu recovery of 95.8%. Natarajan et al ( 2001) used Bacillus polymyxa as a collector and found that its metabolites can change the surface properties of quartz and kaolinite and increase the floatability of quartz and kaolinite.…”

Section: ．Introductionmentioning

confidence: 99%

Selective depression of Escherichia coli on flotation of collophanite and dolomite

Li¹,

Nie²,

Jin³

et al. 2022

Physicochem. Probl. Miner. Process.

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The phosphate rock flotation test was carried out using Escherichia coli (E. coli) as a depressant of dolomite. The results showed that E. coli had a great selective depression on dolomite during flotation. With E. coli as a depressant of dolomite, a useful beneficiation index of phosphorus concentrate with P2O5 grade of more than 30% and MgO content less than 1.2% can be obtained by closed-circuit of one-stage roughing and one-stage cleaning. Furthermore, the depression mechanism of E. coli was studied by adsorption experiments, infrared spectrum, and zeta potential. This study shows that the adsorption ability of E. coli onto dolomite is stronger than that of collophanite. When the pH is greater than 6, E. coli are chemically adsorbed on the surface of the collophanite and dolomite,which also increases the negative charge on the surface of the two minerals. The selective adsorption of E. coli cells to dolomite was best when the pH value is about 7.8.

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Selective Attachment of Leptospirillum ferrooxidans for Separation of Chalcopyrite and Pyrite through Bio-Flotation

Cited by 12 publications

References 44 publications

Review of Potential Microbial Effects on Flotation

Review of Potential Microbial Effects on Flotation

Towards the Biobeneficiation of PGMs: Reviewing the Opportunities

Selective depression of Escherichia coli on flotation of collophanite and dolomite

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