Content uploaded by Dimitrios Panias
Author content
All content in this area was uploaded by Dimitrios Panias
Content may be subject to copyright.
A preview of the PDF is not available
Exergetic analysis of the ENEXAL bauxite residue treatment on the overall resource efficiency of the primary alumina refining process
Abstract and Figures
In the framework of the ENEXAL FP7 project, a novel process for treating bauxite residues has been developed and demonstrated in industrial scale. The novel process developed, fully converts the bauxite residues in to marketable products such as pig iron and mineral wool fibers. In this work a detailed exergy analysis of the new process is presented and coupled with the flow-sheet of the primary alumina refining process (Bayer), in order to deduce its effect on the overall resource efficiency and exergy utilization. A methodology for evaluating the chemical exergy of mineral phases and solid solutions is also discussed.
Figures - uploaded by Dimitrios Panias
Author content
All figure content in this area was uploaded by Dimitrios Panias
Content may be subject to copyright.
... The total energy consumption of the pilot plant is calculated to around 2000 -2200 kWh/ton of BR, taking into account utilities like the static BR dryer (160-280 kWh/t BR) the water pumps for the cooling water (60 kWh/t BR) and the bag filter air compressors (110 kWh/t Br). Still even with a 2000 kWh/t BR electrical energy consumption the novel process could significantly improve the resource utilization efficiency of the alumina refining plant as discussed by the authors in [11]. Accordingly, the exergy efficiency of the BR treatment is 32% and when integrated in the alumina refinery flowsheet it increases the overall exergy efficiency of the plant from 3% to 12%. Figure 7. ...
The main by-product of the Bayer process is the bauxite residues (BR), a red slurry consisting of the un-dissolved portion of the bauxite ore. On a dry basis BR are produced at an almost 1:1 mass ratio with alumina, amassing to a total of 100 to 120 million tones per year globally. Due the lack of an economically viable processing method all BR are disposed in artificial ponds or landfills. A novel process for treating BR has been developed; Through EAF carbothermic smelting the BR are fully converted into two marketable products: pig iron and mineral wool fibers. No solid or liquid by-products are produced. This novel process has been applied for more than a year in an industrial scale pilot plant housing a 1MVA EAF and a melt fiberizing line. The mass and energy balance of the process, along with a preliminary scale up calculations are presented in this paper.
... The total energy consumption of the pilot plant is calculated to around 2000 -2200 kWh/ton of BR, taking into account utilities like the static BR dryer (160-280 kWh/t BR) the water pumps for the cooling water (60 kWh/t BR) and the bag filter air compressors (110 kWh/t Br). Still even with a 2000 kWh/t BR electrical energy consumption the novel process could significantly improve the resource utilization efficiency of the alumina refining plant as discussed by the authors in [11]. Accordingly, the exergy efficiency of the BR treatment is 32% and when integrated in the alumina refinery flowsheet it increases the overall exergy efficiency of the plant from 3% to 12%. Figure 7. ...
The main by-product of the Bayer process is the bauxite residues
(BR), a red slurry consisting of the un-dissolved portion of the
bauxite ore. On a dry basis BR are produced at an almost 1:1 mass
ratio with alumina, amassing to a total of 100 to 120 million tones
per year globally. Due the lack of an economically viable
processing method all BR are disposed in artificial ponds or
landfills. A novel process for treating BR has been developed;
Through EAF carbothermic smelting the BR are fully converted
into two marketable products: pig iron and mineral wool fibers.
No solid or liquid by-products are produced. This novel process
has been applied for more than a year in an industrial scale pilot
plant housing a 1MVA EAF and a melt fiberizing line. The mass
and energy balance of the process, along with a preliminary scale
up calculations are presented in this paper.
... 11. Details on exergy flow calculations are presented elsewhere [13]. ...
This work outlines an integrated methodology for converting metallurgical by-products into high added value products, through an essentially zero-waste process. Thermodynamic modelling and conceptual design for processing bauxite residues (red mud) from the primary aluminium industry and ferro-nickel production slags are presented as examples. Furthermore, results of semi-industrial scale experiments for processing bauxite residues are illustrated, along with a preliminary financial analysis and an exergy flowsheet of the new conceptual alumina refinery, all confirming the financial viability as well as the resource-efficient utilization of the proposed technology.
This paper discusses the progress of second law analysis, considering particularly the work which has been accomplished in this line in Europe. The list of literature takes into account exemplary publications by the most popular authors dealing with this subject. The achievements of the author, concerning the determination of the chemical exergy and the economical applications of exergy, are discussed more broadly.
The focus in environmental research is shifting from emission abatement to critical process analysis, including assessment of resource consumption. The exergy theory offers a thermodynamic methodology to account for the consumption of natural resources. However, exergy data on mineral resources available in the literature are inadequate to apply to exergetic life cycle analysis, due to incompleteness, inconsistencies, and a dated thermochemical basis. An uncertainty assessment of the data has to be performed as well. In this work, three recent thermochemical databases were applied to evaluate the chemical exergy of 85 elements and 73 minerals, 21 of which had not yet been quantified in the literature. The process required the choice of a new reference species for aluminum. Muscovite was selected, giving rise to a chemical exergy of 809.4 kJ/mol for aluminum. The theory proved to be robust for the exergy of chemical elements, as exergy values differing by 1.2% on average from most recent literature were found. On the contrary, the exergy values for minerals differed by factors up to 14 from literature values, due to the application of recent thermochemical values and consistently selected reference species. The consistent dataset of this work will enable straightforward resource intake evaluation through an exergetic life cycle assessment.
Wel/-to-Wheel Studies, European Fuel Cell Forum
. Bossel U., Wel/-to-Wheel Studies,
European Fuel Cell Forum, 2003
The efficiency of industrial processes: Exergy analysis and optimization
- V M Brodyansky
Brodyansky V.M. et aI., The efficiency of industrial processes: Exergy analysis and optimization,
Elsevier Science B.v., 1994
- D E Balomenos
- I Panias
. E. Balomenos, D. Panias, I. Paspaliaris, Mineral Processing & Extractive Metall. Rev., 32: 69-89,
2011
- E Balomenos
- D Panias
- I Paspaliaris
E. Balomenos, D. Panias, I. Paspaliaris, Mineral Processing & Extractive Metall. Rev., 32: 69-89,
2011
Wel/-to-Wheel Studies
- U Bossel
Bossel U., Wel/-to-Wheel Studies,
European Fuel Cell Forum, 2003