Characteristics of carbide slag slurry flow in a bubble column carbonation reactor

The direct aqueous mineral carbonation of carbide slag was investigated. The flow characteristics of carbide slag-CO2-water reaction system in a bubble column were studied, which included the bubble Sauter mean diameter, gas holdup, bubble residence time, and the gas-liquid interfacial area. Bubble flow behaviors in the reactor were characterized by analyzing the bed pressure signals. The effects of the gas velocity (U- g ) and liquid to solid ratio (L/S ratio) were discussed and analyzed. The results showed that the larger bubbles were easy to form at the larger L/S ratio, which indicated that the bubble coalescence was promoted. The gas holdup was larger when increasing U- g or reducing the L/S ratio. The better gas-liquid interfacial areas were found in a wide range of L/S ratio at U- g = 0.082 m/s. The optimum conditions were found at U- g = 0.082 m/s and L/S ratio = 15-30 mL/g for the better gas-liquid interfacial area and the higher carbide slag conversion. The work provided the theoretical basis for the direct aqueous carbonation of the carbide slag and the operation condition optimization.