A renewable porous ceramic developed by rice husk and granite cutting sludge

This study addresses the issues related to the consumption of granite cutting sludge and rice husk. The rice husks were sourced from the rice farming, while the granite powders were derived from granite cutting sludge. The granite powders were densified through sintering at high temperature. The effects of rice husk content and sintering temperature on the microstructures, absorption capacities and mechanical properties of porous ceramics were investigated. It is found that the granite powders mixed with 10% rice husk and sintered at 1060 °C exhibit excellent performance, including a water absorption capacity of 26% and a compressive strength of 40 MPa. These results are comparable to commercial porous ceramics but lower sintering temperature. Consequently, this porous ceramic significantly enhances grass growth. Therefore, the porous ceramic demonstrates its potential as a new water absorption material, effectively addressing the waste issues of granite cutting sludge and rice husk in Taiwan.