<abstract xmlns="http://www.w3.org/1999/xhtml"><p>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.</p></abstract>

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.

Alkali-reduced Bauxite Residue as Novel SCM

Nordic Concrete Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Alkali-reduced Bauxite Residue as Novel SCM"}

Bauxite residue is a major waste stream available in large volumes globally that can cause risks to the surrounding environment (e.g. ecotoxicity) when...

Alkali-reduced Bauxite Residue as Novel SCM

Published Online: Dec 31, 2020

Page range: 1 - 20

Received: Sep 28, 2020

Accepted: Nov 26, 2020

DOI: https://doi.org/10.2478/ncr-2020-0015

Keywords
Bauxite residue, red mud, pozzolan, cement, acetic acid, alkali reduction, sodium acetate

© 2020 Tobias Danner et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Alkali-reduced Bauxite Residue as Novel SCM

Published Online: Dec 31, 2020

Page range: 1 - 20

Received: Sep 28, 2020

Accepted: Nov 26, 2020

DOI: https://doi.org/10.2478/ncr-2020-0015

KeywordsBauxite residue, red mud, pozzolan, cement, acetic acid, alkali reduction, sodium acetate

© 2020 Tobias Danner et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Bauxite residue, red mud, pozzolan, cement, acetic acid, alkali reduction, sodium acetate