One-step sintering process for high-performance SiC membranes for efficient filtration of dust-laden gas

Silicon carbide (SiC) ceramic membranes are known for their remarkable attributes, including resistance to acid and alkali corrosion, exceptional tolerance to thermal shock, and high mechanical strength. These properties have garnered considerable attention for dust-laden gas filtration. However, large-scale applications of SiC membranes are limited because of the high sintering energy consumption in membrane formation. In this study, a preparation method for high-performance and low-cost SiC membranes using a co-sintering process was proposed. In this method, SiC particles with a 100-μm average particle size were uniformly mixed with sintering aids and SiC green supports were prepared via a dry pressing process. Subsequently, SiC dispersion was coated on the SiC green supports via a spray coating method to prepare membrane layer. Through optimization of the sintering process and sintering atmosphere, the sintering stress difference during co-sintering was released. Finally, a defect-free membrane surface was fabricated. The carbon powder in the green supports was utilized as a pore-forming agent and to prevent small particles in the SiC membrane layers from infiltrating the SiC green supports, decreasing the mass transfer resistance in the application process. The SiC ceramic membrane had a mean pore size and a gas permeance of 3.90 μm and 246.33 m³ m⁻² h⁻¹ kPa^-1. In addition, when subjected to identical average pore size and porosity conditions, it exhibited a high Darcy's permeability coefficient, indicating favorable structural characteristics for the membrane. Additionally, the membrane was optimized to have a 99.9 % rejection of solid particles in dusty gases, including nanometer (0.3 μm) and micron (2.5 μm) solid particles. This study has introduced a preparation method for low-cost and high-performance SiC membranes for industrial dust-laden gas filtration.