Effect of Rice Husk and Sugarcane Bagasse Pore Formers on the Mechanical Properties of Kaolin Ceramic

Abstract

The increasing focus on environmental sustainability has generated significant interest in the use of agricultural wastes particularly monocot-based materials rich in silica (SiO₂) as pore-forming agents in ceramic development. Their low cost, ease of handling, and commercial availability make them promising candidates for producing porous ceramics with tailored pore structures. Despite the abundance and economic potential of kaolin clay in Nigeria, its applications remain underutilized. This study investigates the effect of rice husk (RH) and sugarcane bagasse (SCB) as sustainable pore-forming agents on the mechanical properties of Gwarzo kaolin. Porous ceramic samples were fabricated using the pore-forming technique (PFT), incorporating locally sourced kaolin with varying weight percentages (3%, 6%, and 9%) of RH and SCB. After firing, the sacrificial pore-formers were eliminated to generate porosity. Mechanical properties, specifically compressive strength, tensile strength, and hardness, were evaluated. For RH-incorporated samples, compressive strengths of 5.33 MPa, 3.16 MPa, and 1.96 MPa were recorded for 3%, 6%, and 9% compositions, respectively. In contrast, SCB-based samples exhibited compressive strengths of 3.35 MPa, 1.17 MPa, and 0.58 MPa at corresponding compositions. Similarly, the tensile strengths for RH samples were 0.83 MPa, 0.53 MPa, and 0.26 MPa, outperforming the SCB samples, which recorded 0.55 MPa, 0.25 MPa, and 0 MPa. Hardness values for RH samples were 64.5 HV, 57.3 HV, and 48.7 HV, compared to 56.6 HV, 45.5 HV, and 0 HV for SCB samples. The results indicate that rice husk is a more effective pore-forming agent than sugarcane bagasse in enhancing the mechanical performance of kaolin-based porous ceramics.