Novel Low-Temperature Fabricated Coal Gangue-Based Porous Ceramics: Water Absorption/Retention Features and Their Application in Dryland Agriculture

This study addresses water scarcity in arid regions by developing low-temperature-sintered porous ceramics for agricultural water management, utilizing coal gangue solid waste as the primary resource. Systematic single-factor experiments first identified the optimal sintering temperature (615 °C) and polystyrene content (25%) that critically balance pore formation and structural integrity. Building on this, orthogonal experiment optimization yielded an optimal formulation exhibiting exceptional comprehensive performance (coal gangue 20 g, starch 25 g, glass powder 11 g, polystyrene 27 g): 149.70% water absorption, 57.75 h water retention, 77.28% porosity, and 0.55 MPa compressive strength. The material’s graded pore structure, achieved through composite pore-formers (polystyrene/starch) and diatomaceous earth, underlies its enhanced capillary action. The pot experiment of Chinese cabbage confirmed its effect, shortened the emergence time of seedlings to <24 h, and significantly improved the emergence rate and the growth of seedlings in the early stage (7 days). This work provides a new way for the value of coal gangue in dryland agriculture and ecological restoration.