Studies on mass transfer coupled with chemical reaction were conducted in a gas-liquid-solid foam bed contactor under a variety of operating conditions in order to establish the controlling parameters for such a contacting system. Analytical equations were derived in order to predict the influence of solids dissolution on the specific rate of absorption in the stable foam stage of a three-phase foam-slurry reactor. Experimental investigations on the absorption of carbon dioxide in the presence of an aqueous foam-slurry containing calcium hydroxide particles were carried out in order to verify the theoretical model. Results indicate that the gas-liquid interfacial area and gas flow rate strongly affected the rate of mass transfer, while solids holdup affected mass transfer rates only moderately over the range of solids holdup studied. A comparison with conventional chemical reactor configurations (e.g., bubble column, CSTR) was made to demonstrate the gas-liquid-solid system, for which this novel reactor might be employed. Foam stability enhancement, due to the presence of solid particles, was not observed.