Aluminium fluoride complexation and its ecological importance in the aquatic environment

Radić, Njegomir; Bralić, Marija

doi:10.1016/0048-9697(95)04818-9

Cited by 17 publications

(11 citation statements)

References 14 publications

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“…The Al F complexes were dominant at acidic conditions before titration. As OH − was added, Al F complexes were partly dissociated to Al 3+ , free fluoride and other species, such as Al(OH) 2+ and AlF(OH) + [5,15]. In aqueous solution the soluble species mainly included Al F complexes, Al OH complexes, Al 3+ and free fluoride.…”

Section: Al Hydrolysis With Al F Complexationmentioning

confidence: 99%

Effect of aluminum fluoride complexation on fluoride removal by coagulation

Gong¹,

Qu²,

Liu³

et al. 2012

Colloids and Surfaces A: Physicochemical and Engineering Aspect

131

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a b s t r a c tEffect of aluminum fluoride complexation on fluoride removal by Al salts coagulation was investigated by a series of batch experiments. Transformation of fluoride species in coagulation was studied by simultaneous determination of free fluoride and total fluoride at different pH and fluoride concentrations. Results showed that aluminum fluoride complexes dominated at low pH and high fluoride concentrations but more complexes did not represent higher fluoride removal. Comparison between coagulation with complexation and adsorption by Al(OH) 3 flocs was conducted and coagulation showed higher fluoride removal efficiency than adsorption in the pH range of 6.0-9.0. Titration test showed that Al F complexes were coprecipitated with less OH − than Al 3+ . Characterization of FTIR and XPS also indicated that flocs after complexation was different from Al(OH) 3 flocs with or without fluoride. It was concluded that a new Al F OH coprecipitate formed in coagulation and fluoride was effectively removed by the coprecipitation.

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Section: Al Hydrolysis With Al F Complexationmentioning

confidence: 99%

Effect of aluminum fluoride complexation on fluoride removal by coagulation

Gong¹,

Qu²,

Liu³

et al. 2012

Colloids and Surfaces A: Physicochemical and Engineering Aspect

131

View full text Add to dashboard Cite

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“…The impact of the bioleach solution composition on the concentration of the HF species was investigated at 65˝C using Sulfolobus metallicus growing on pyrite (initial solution pH 1.5) and monitoring changes in ORP as a surrogate measure of microbial activity and growth [84]. The tests varied in the concentration of aluminium added to the growth medium, in the knowledge that Al(III) (and Fe(III)) form Al-or Fe-fluoride complexes [85][86][87]. A similar strategy of aluminium addition counteracted fluoride toxicity during the bioleaching of a low-grade, fluoride-containing ore using S. thermosulfidooxidans (50˝C, growth media in the range pH 1.4-2.1) [88], demonstrating that, if fluoride solubilisation is accompanied by strong aluminium or iron(III) solubilisation from gangue minerals, then the effects on the microorganisms may be substantially mitigated due to the formation of aluminium-or iron(III)-fluoro complexes.…”

Section: Anionsmentioning

confidence: 99%

Microbiological Advances in Biohydrometallurgy

Watling

2016

Minerals

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The most exciting advances in biohydrometallurgy are occurring in the field of microbiology. The two main technologies employed in biohydrometallurgy, agitated tanks for the processing of refractory concentrates and heaps and dumps for the processing of low-grade ores, are technologically sound and widely practised at commercial scale, but their development began at a time when very little was known of the microorganisms that assisted metals extraction from sulfide ores. During and subsequent to those developments it has been shown that microbial communities in metals extraction are more diverse than originally thought, and extremely robust and adaptable to different and variable environments. Recent advances in genomics and proteomics, exploiting hugely increased computing power and speed, have made it possible to describe not only which microorganisms are present in bioleaching systems, but also what physiological functions are being exercised. The body of knowledge being acquired through the application of molecular biology methods will be used increasingly to monitor microbial behaviour, optimise conditions for more appropriate microbiological activity and/or infer the "microbiological health" of bioreactors (tanks and heaps).

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“…However, if fluoride release to solution is accompanied by strong aluminium or iron solubilisation from gangue minerals, then the effects on the microorganisms may be substantially mitigated, due to the formation of complexes [138][139][140][141][142].…”

Section: Microbial Growth Under Element Stressmentioning

confidence: 99%

Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

Watling

2014

Minerals

140

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This review has as its underlying premise the need to become proficient in delivering a suite of element or metal products from polymetallic ores to avoid the predicted exhaustion of key metals in demand in technological societies. Many technologies, proven or still to be developed, will assist in meeting the demands of the next generation for trace and rare metals, potentially including the broader application of biohydrometallurgy for the extraction of multiple metals from low-grade and complex ores. Developed biotechnologies that could be applied are briefly reviewed and some of the difficulties to be overcome highlighted. Examples of the bioleaching of polymetallic mineral resources using different combinations of those technologies are described for polymetallic sulfide concentrates, low-grade sulfide and oxidised ores. Three areas for further research are: (i) the development of sophisticated continuous vat bioreactors with additional controls; (ii) in situ and in stope bioleaching and the need to solve problems associated with microbial activity in that scenario; and (iii) the exploitation of sulfur-oxidising microorganisms that, under specific anaerobic leaching conditions, reduce and solubilise refractory iron(III) or manganese(IV) compounds containing multiple elements. Finally, with the successful applications of stirred tank bioleaching to a polymetallic tailings dump and heap bioleaching to a polymetallic black schist ore, there is no reason why those proven technologies should not be more widely applied.

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Aluminium fluoride complexation and its ecological importance in the aquatic environment

Cited by 17 publications

References 14 publications

Effect of aluminum fluoride complexation on fluoride removal by coagulation

Effect of aluminum fluoride complexation on fluoride removal by coagulation

Microbiological Advances in Biohydrometallurgy

Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

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