Mud2Metal: Lessons Learned on the Path for Complete Utilization of Bauxite Residue Through Industrial Symbiosis

Balomenos, Efthymios; Davris, Panagiotis; Pontikes, Yiannis; Panias, Dimitrios

doi:10.1007/s40831-016-0110-4

Cited by 29 publications

(28 citation statements)

References 44 publications

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“…The production of 1 ton of alumina generates between 0.9 and 1.5 ton of residue depending on the composition of initial bauxite ore [2,3]; the handling of this byproduct is a major challenge for the alumina industry due to its high volume and high alkalinity [4,5]. However, bauxite residue can be considered as a secondary raw material resource, due to the presence of valuable substances such us iron (Fe), titanium (Ti), aluminum (Al), and rare earth elements (REEs) [6,7]. Indeed, in numerous studies, different processes have been developed to recover elements from BR [8,9].…”

Section: Introductionmentioning

confidence: 99%

Iron Recovery from Bauxite Residue Through Reductive Roasting and Wet Magnetic Separation

Cardenia

Balomenos

Panias

2018

J. Sustain. Metall.

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The scope of this work is to develop and optimize a reductive roasting process followed by wet magnetic separation for iron recovery from bauxite residue (BR). The aim of the roasting process is the transformation of the nonmagnetic iron phases found in BR (namely hematite and goethite), to magnetic ones such as magnetite, wüstite, and metallic iron. The magnetic iron phases in the roasting residue can be fractionated in a second stage through wet magnetic separation, forming a valuable iron concentrate and leaving a nonmagnetic residue containing rare earth elements among other constituents. The BR-roasting process has been modeled using a thermochemical software (FactSage 6.4) to define process temperature, Carbon/Bauxite Residue mass ratio (C/BR), retention time, and process atmosphere. Roasting process experiments with different ratios of C/BR (0.112 and 0.225) and temperatures (800 and 1100°C), 4-h retention time, and, in the presence of N 2 atmosphere, have proven almost the total conversion of hematite to iron magnetic phases ([ 99 wt%). Subsequently, the magnetic separation process has been examined by means of a wet high-intensity magnetic separator, and the analyses have shown a marginal Fe enrichment in magnetic fraction in relation to the sinter.

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Section: Introductionmentioning

confidence: 99%

Iron Recovery from Bauxite Residue Through Reductive Roasting and Wet Magnetic Separation

Cardenia

Balomenos

Panias

2018

J. Sustain. Metall.

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“…Particularly interesting is the case of scandium (Sc), as its concentration in BR (in Greek BR accounts to 130 ppm on average) is much higher than in the Earth's crust (22 ppm on average [8]); that means a notable enrichment of Sc in BR. Due to the high market price (Sc 2 O 3 -4600 US$/kg, 99.99% purity, in 2017) [9], Sc may represent 95% of the economic value of rare earths in BR [10]. It has also…”

Section: Introductionmentioning

confidence: 99%

Scandium and Titanium Recovery from Bauxite Residue by Direct Leaching with a Brønsted Acidic Ionic Liquid

Bonomi

Alexandri

Vind

et al. 2018

Metals

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In this study, bauxite residue was directly leached using the Brønsted acidic ionic liquid 1-ethyl-3-methylimidazolium hydrogensulfate. Stirring rate, retention time, temperature, and pulp density have been studied in detail as the parameters that affect the leaching process. Their optimized combination has shown high recovery yields of Sc, nearly 80%, and Ti (90%), almost total dissolution of Fe, while Al and Na were partially extracted in the range of 30-40%. Si and rare earth element (REEs) dissolutions were found to be negligible, whereas Ca was dissolved and reprecipitated as CaSO 4 . The solid residue after leaching was fully characterized, providing explanations for the destiny of REEs that remain undissolved during the leaching process. The solid residue produced after dissolution can be further treated to extract REEs, while the leachate can be subjected to metal recovery processes (i.e., liquid-liquid extraction) to extract metals and regenerate ionic liquid. been listed as a critical raw material by the European Commission due to its high economic importance and supply risk [11]. In fact, Sc is mainly produced as a byproduct during the processing of various ores, from titanium and REEs ores (China), uranium ore (Kazakhstan and Ukraine), and apatite ore (Russia). It can also be recovered from previously processed tailings or residues [9,12,13]. For these reasons, BR can be accounted as a secondary raw material source [14], and the recovery of Sc could represent a high economic interest.BR can also be considered a secondary source for Ti, which is a photocatalyst and it is applied in the white pigment industry [15]. Since the availabilities and qualities of Ti ores are decreasing [16], it is important to find methods for extracting Ti from secondary sources.Many studies, patents, and pilot scale implementations have been carried out for Sc and Ti recovery from BR, mainly by investigating hydrometallurgical or combined pyro-hydrometallurgical processes [5,12,[16][17][18][19][20][21][22][23], but none of them has reached an industrial scale. Nowadays, the impact of the zero-waste valorization policy motivates the research community on finding innovative, greener, and economical viable routes for metal extraction from complex polymetallic matrices, such as the bauxite residue [24].Ionometallurgical approach can be exploited as an alternative to conventional hydrometallurgical processing. The term ionometallurgy indicates the use of ionic liquids (ILs) as solvents in metals processing. ILs are liquid at room temperature and consist solely of ions; generally an organic cation and inorganic/organic anion. ILs have superior properties against conventional organic solvents, such as nonflammability, a wide electrochemical window, high thermal stability, negligible vapor pressure, and low volatility [25]. For these reasons and thanks to the vast number of combinations of the cation and the anion during synthesis, ILs have potential for many applications, such as solvent extraction [26,27], catalytic reactions [28,...

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“…As a result, a commonly proposed valorization route for BR is the extraction of this iron via various methods. The technological feasibility of extracting iron from BR is well established [14][15][16], and iron recovery is carried out on an industrial scale at some plants in China, however, a widespread economically viable, industrial scale process for iron recovery from BR, particularly European BR, remains elusive.…”

Section: Bulk Metals: Iron and Aluminiummentioning

confidence: 99%

Using Life Cycle Thinking to Assess the Sustainability Benefits of Complex Valorization Pathways for Bauxite Residue

Joyce

Björklund

2019

J. Sustain. Metall.

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Bauxite residue, the main waste product of alumina production, is a potentially valuable secondary resource. The MSCA-ETN REDMUD project aims to develop environmentally friendly technologies to realize this value, by extracting valuable metals (aluminium, iron, titanium, scandium, rare-earth elements) or utilizing it in construction applications. Simply utilizing a waste product as an input is not, however, sufficient to claim that a process is environmentally friendly; the processes developed must be demonstrably better for the environment, from a life cycle perspective, than business as usual. The earlier in the research and development process that environmental information can be taken into account, the more impact it can have on decision-making. In this study we demonstrate that Life Cycle Thinking approaches can provide actionable environmental information at an early stage in the research process, and that in doing so it can help steer early stage technology development towards overall improved industry environmental performance. Knowledge of the potential environmental benefit from displacing different materials can help identify primary or additional targets, for example the use of metal extraction residues for construction materials. A high-level 'red flags' assessment of the relative environmental impact of inputs to valorization processes and the products they displace can be used to identify problematic inputs and processes in the absence of quantitative details. Finally, once preliminary quantitative data are available for a process, streamlined Life Cycle Assessment can be used to calculate the environmental balance of a process, and identify specific hotspots of environmental impact.

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Mud2Metal: Lessons Learned on the Path for Complete Utilization of Bauxite Residue Through Industrial Symbiosis

Cited by 29 publications

References 44 publications

Iron Recovery from Bauxite Residue Through Reductive Roasting and Wet Magnetic Separation

Iron Recovery from Bauxite Residue Through Reductive Roasting and Wet Magnetic Separation

Scandium and Titanium Recovery from Bauxite Residue by Direct Leaching with a Brønsted Acidic Ionic Liquid

Using Life Cycle Thinking to Assess the Sustainability Benefits of Complex Valorization Pathways for Bauxite Residue

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