Particle size dependence of CO_2 absorption rate of powdered Li_4SiO_4 with different particle size

概要

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Particle size dependence of CO_2 absorption rate of powdered Li_4SiO_4 with four kinds of particle sizes was studied by SEM observation, particle size distribution measurement, and thermogravimetry. Average particle sizes of the powdered single phase Li_4SiO_4 samples were estimated about 26μm, 34μm, 53μm, 70μm, respectively by the particle size distribution measurement and SEM observation. The measurement of apparent rate constant k for the CO_2 absorption reaction showed that k values of all the powdered Li_4SiO_4 samples increase with the increasing measurement temperature T, following the Arrhenius equation in the region of 620-660℃, while the k values abruptly increase deviating the Arrhenius equation over 670℃. It was also noted that the k values seem to depend on the particle size of the powdered Li_4SiO_4 samples, that is, the k values increase with the decreasing particle size. Moreover, difference between the k values of all the powdered samples at same temperature was found small in the region of 620-660℃, while the difference was found large over 670℃. For Li_4SiO_4 with smaller particle size, Δk=k_<700℃>-k_<660℃> was found larger, vice versa, the Δk was found smaller for Li_4SiO_4 with larger particle size. The values seem to correspond with reaction mechanism for CO_2 absorption of Li_4SiO_4 particle.
社団法人日本セラミックス協会の論文
2008-12-01