On the Mechanism of Sodic Removal from Bauxite Residue and Bauxite Desilication Products (BDP) Using Acetic Acid

Wang, Sicheng; Nguyen, Tuan A.H.; Peng, Hong; Huang, Longbin

doi:10.1007/s11837-019-03884-z

Cited by 10 publications

(9 citation statements)

References 47 publications

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“…Besides Na2O it seems that some minor amounts of silica, alumina and calcium oxide were washed out as well. The reason is most likely the structural breakdown of sodalite and other alkaline minerals of the desilication product by hydrolysis [20]. The destruction of sodalite was confirmed by X-Ray analysis (Figure 2).…”

Section: Acetic Acid Treatment Of Brmentioning

confidence: 78%

“…The process of alkali reduction of BR was adapted based on the experiments performed in [20]. Moist BR "as received" was washed with 0.5 M acetic acid in a ratio of acetic acid/dry BR = 10.…”

Section: Methodsmentioning

confidence: 99%

“…The main peaks of sodalite disappeared in AR-BR while the main peaks of hematite, goethite and gibbsite were unaffected by the acetic acid treatment. Ion exchange reaction of Na + with H + in the desilication product, hydrolysis of Al-and Si species and organic surface complexation (chelation reactions) [20] might be responsible for the higher LOI value of AR-BR besides the same drying conditions before analysis. It is worth noting that aluminium triacetate will hydrolyse in water to aluminium diacetate hydroxide (so called basic aluminium acetate) that is insoluble.…”

Section: Acetic Acid Treatment Of Brmentioning

confidence: 99%

“…Neutralization of BR by mixing with lime for the use as construction material has been investigated [19]. Based on a recent publication, looking at soil formation from BR deposits for sustainable plant colonialization [20] we intend to carry out in this study a simple washing process of BR with diluted acetic acid to produce a low alkali SCM. The proposed approach has the potential to be implemented on industrial scale and could help solving waste management problems of alumina plants while at the same time producing a novel large volume SCM and thus decreasing the CO2 footprint of common cementitious binders.…”

Section: Introductionmentioning

confidence: 99%

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Alkali-reduced Bauxite Residue as Novel SCM

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Sletnes

Justnes

2020

Nordic Concrete Research

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Bauxite residue is a major waste stream available in large volumes globally that can cause risks to the surrounding environment (e.g. ecotoxicity) when disposed and stored by conventional methods. There is yet no large-scale application and the utilization as supplementary cementitious material might be the best way to re-use bauxite residue. The main obstacle for the utilization of bauxite residue in the construction industry is the high alkalinity. This paper presents first results of a study on alkali reduction of bauxite residue by acetic acid treatment and the potential application of this alkali reduced bauxite residue as pozzolan in cementitious binders. A process of alkali reduction is presented that can help solving waste management problems of alumina refineries by transforming bauxite residue to a less hazardous waste, while producing a reactive pozzolan and Na-acetate that can find application in the construction and infrastructure market. 90% alkalinity reduction of bauxite residue could be achieved by simply washing with diluted acetic acid. Alkali-reduced bauxite residue showed good pozzolanic reactivity regarding portlandite consumption, bound water and 28-day compressive strength of mortars with 20% replacement of OPC.

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Section: Acetic Acid Treatment Of Brmentioning

confidence: 78%

Section: Methodsmentioning

confidence: 99%

Section: Acetic Acid Treatment Of Brmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Alkali-reduced Bauxite Residue as Novel SCM

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Sletnes

Justnes

2020

Nordic Concrete Research

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“…Before acid treatment, XPS peaks of Al 2p and Si 2p of bauxite residue appeared at around 71.9 and 99.4 eV, respectively. 8,19 However, with increasing acid concentrations, both peak intensities of Al 2p and Si 2p have insignificantly changed. This phenomenon may relate with the contribution of boehmite and quartz.…”

Section: Acid Treatment Of Bauxite Residuementioning

confidence: 99%

Revealing the Mechanisms of Metal Adsorption by Bauxite Residue

Peng

Vaughan

et al. 2023

Ind. Eng. Chem. Res.

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Acid treatment of bauxite residue (BR) has been one of the main approaches to enhance its metal adsorption performance. However, the acid treatment mechanisms remain poorly understood and is complicated by the variable and complex mineralogy of bauxite residue and different test conditions in previous studies. In this study, bauxite residue samples were treated with aqueous HCl solutions, with concentrations ranging from 0 to 0.25 M. The dissolution kinetics of the major elements (Na, Al, Ca, Fe, and Si) and target metals (Pb 2+ and Cu 2+ ) for ion exchange and adsorption performance were measured. The solid samples were examined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) cross-sectional elemental mapping to determine the reaction mechanisms. The results revealed that the adsorption performance decreased with increasing acid concentrations, which is related to the structural changes of the sodalite phase. Other mineral phases, such as hematite, boehmite, and quartz, play a minor role in the adsorption. Additionally, different adsorption mechanisms between Pb 2+ and Cu 2+ were revealed, which were related to surface disruption.

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