Ecological geopolymer produced with a ternary system of red mud, glass waste, and Portland cement

• Published in: Cleaner Engineering and Technology 2022-02, Vol.6, p.100379, Article 100379
• Main Authors: Gomes Silveira, Nathália Cristina, Figueiredo Martins, Maysa Lorena, Bezerra, Augusto Cesar da Silva, Gabriel da Silva Araújo, Fernando
• Format: Article
• Language: English
• Subjects: Geopolymer; Glass waste; Red mud; Sustainability
• ISSN: 2666-7908; 2666-7908
• DOI: 10.1016/j.clet.2021.100379

In this study, the use of residues from the processing of bauxite and glass powder as precursors for the preparation of geopolymers was evaluated. The route used was an alkaline solution of NaOH with three different molarities. Nine compositions of the percussion (waste) and the activator used were verified. XRF, XRD, laser granulometry, SEM, FTIR, BET, DTG, and compressive strength tests were used to verify the physical and chemical characteristics of the residues used and the geopolymers obtained. Some geopolymers developed efflorescence on their surfaces, indicating a higher alkali content. The compressive strength increased with the addition of small amounts of Portland cement (5%). The composition with the best performance exhibited a compressive strength of 11.35 ± 1.23 MPa after 28 days. The results of the chemical analysis showed the formation of the characteristic gel of the geopolymers. However, the primary finding was that the amount of activator (sodium hydroxide) proved to be inefficient because of the intrinsic alkaline properties of the red mud, which were already effective in the alkaline activation process. [Display omitted]