Cassava Peel from D. R. Congo as a Sustainable Pore-Forming Agent for Kaolin-Based Ceramics: Tailoring Properties for Advanced Applications

The effects of cassava peeling waste (CPW) on the properties of kaolinite-based ceramics were ascertained to develop a lightweight, porous ceramic that can be used as a building material with enhanced properties. Different amounts of cassava waste (i.e., 0, 10, 15, and 20%) were used to formulate ceramic specimens from clay samples collected in various locations of Songololo and Kinshasa in D.R. Congo. Both clays and the cassava waste were subjected to chemical analysis by X-ray fluorescence (XRF) and (CHNO-S), mineralogical analysis (XRD), thermal analysis (DTA and TG), granulometric analysis, and Fourier transform infrared spectroscopy (FTIR). Ceramic specimens were produced after sintering to 1000, 1100, and 1200 °C. Upon sintering to 1200 °C, red clay-based ceramics achieved acceptable properties with high porosity (29.1–43.9%), water absorption (15.1 to 28.9%), and apparent density (1.6–1.9 g/cm³). Gray clay-based ceramics showed lower porosity (17.4–33.5%) and water absorption (7.9–19.6%), but almost similar bulk density (2.1–1.7 g/cm³) at the highest sintering temperature of 1200 °C. As the proportion of cassava waste in the ceramics increased, the heat exchange flux decreased to 0.10 W/mK and 0.06 W/mK for 20% waste added. Despite this decrease, clay-based ceramics from DRC maintained a flexural strength of 2.6 and 2.1 MPa for red and gray clay samples, respectively. These results suggest that CPW has the potential to be used as a pore-forming agent for ceramics with thermal insulating properties.