Cyclic CO2 capture behavior of slag-derived Li4SiO4: A kinetic analysis of CO2 desorption

• Published in: Fuel (Guildford) Vol. 340; p. 127518
• Main Authors: Hernández-Tapia, Vanessa, Vera, Elizabeth, Ramírez-Zamora, Rosa-María, Alcántar-Vázquez, Brenda
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.05.2023
• Subjects: CO2 desorption; Cyclic CO2 capture; Desorption kinetics; Lithium silicate; Metallurgical slag; Lithium silicate; Metallurgical slag; Cyclic CO2 capture; CO2 desorption; Desorption kinetics
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.127518

•Two slag-derived Li4SiO4 were tested during 20 adsorption–desorption cycles.•CO2 desorption is more dependent on temperature than CO2 adsorption.•CO2 desorption on EAF-Li4SiO4 is less dependent on temperature than BF-Li4SiO4.•LiAlO2, Li2CaSiO4, and LiAlSiO4 were formed through consecutive cycles. Two slag-derived Li4SiO4 were synthesized using metallurgical slags as silica sources and used as CO2 sorbents. The CO2 desorption process was studied using a fixed temperature during the sorption step, with different CO2 partial pressures and several desorption temperatures. The kinetic parameters of the CO2 desorption were studied using the Avrami-Erofeev and zero-order models. With the latter, it was possible to calculate the activation energy of the desorption during the first minutes of the process, while with the Avrami-Erofeev model, only the energy associated with the second stage of the model was obtained. The calculated energies with the Avrami model were at least three orders of magnitude greater than the sorption stages reported values. Moreover, both models showed that the Li4SiO4 derived from the electric arc furnace (EAF) slag is less dependent on temperature than the derived from the blast furnace (BF). The kinetic parameters of desorption were also calculated for several regeneration cycles, where it was found that the k values diminish when lower partial pressures of CO2 (PCO2) were used. Finally, the structural evolution after the cyclic study showed the formation of secondary phases in the slag-derived silicates.