Clay Brick Performance with Red Mud, Waste Foundry Sand, and Silica Fume: A Taguchi Approach

Abstract

The disposal of red mud and Waste Foundry Sand (WFS) poses a serious environmental concern. This study investigates the potential of utilizing these industrial by-products, along with silica fume, fly ash, and Desur clay, for the production of geopolymer clay bricks as a sustainable alternative to conventional clay bricks. A 5M geopolymer activator solution, comprising sodium hydroxide and sodium silicate, was used to initiate the geopolymerization process. Nine mix compositions were designed using the Taguchi L9 orthogonal array to evaluate the influence of varying proportions of red mud, silica fume, and WFS on compressive strength and water absorption. Grey Relational Analysis (GRA) was applied to determine the most effective mix composition. The analysis of variance (ANOVA) shows that the silica fume (47.45% is the most significant parameter followed red mud (30.36%). The WFS contribution was the least (21.17%) among all. Microstructural and mineralogical characterizations were conducted using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD), confirming the formation of geopolymeric gels and stable phases. The cast bricks were analyzed for heavy metals using Inductively Coupled Plasma (ICP), which confirmed that the developed bricks are environmentally safe for use. This study demonstrates a practical approach for the sustainable reuse of industrial wastes in brick manufacturing, contributing to waste minimization and the conservation of natural resources.