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

Abstract

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.

Keywords

• Geopolymer
• Red mud
• Glass waste
• Sustainability