A composite reactor with wetted-wall column for mineral carbonation study in three-phase systems

Despite the availability of various reactors designed to study gas-liquid reactions, no appropriate devices are available to accurately investigate triple-phased mineral carbonation reactions involving CO₂ gas, aqueous solutions (containing divalent cations), and carbonate minerals. This report presents a composite reactor that combines a modified conventional wetted-wall column, a pH control module, and an attachment to monitor precipitation reactions. Our test and calibration experiments show that the absorption column behaved largely in agreement with theoretical predictions and previous observations. Experimental confirmation of CO₂ absorption in NaOH and ethanolamine supported the effectiveness of the column for gas-liquid interaction. A test run in the CO₂-NH₃-MgCl₂ system carried out for real time investigation of the relevant carbonation reactions shows that the reactor's performance closely followed the expected reaction path reflected in pH change, the occurrence of precipitation, and the rate of NH₃ addition, indicating the appropriateness of the composite device in studying triple-phase carbonation process.