Expanded graphite powders were prepared by heating natural flake graphites intercalated with sulfuric acid. Graphite matrices were fabricated by pressing expanded graphite powders. Impregnation of salts into the graphite matrices were done using vacuum filtration with 20 wt% CaCl₂ solution followed by vacuum drying at 200℃ and 20kPa. Techniques used to examine the properties of blocks include EDAX and EPMA for amount and distribution of salts in the block, Hepycnometer for porosity, permporometer for gas permeability and transient 1-dimensional heat flow technique for thermal conductivity measurement. Basic chemical heat pump system is used to examine the dimensional stability and temperature distribution for blocks in the reactor. Results showed that Darcy’s permeability constants of graphite matrices were in 0.01-1.0 Darcy at △P=0.8bar. for graphite matrices with P_b= 100-400kg/㎥, thermal conductivites were in the range of 4-22 W/mK. CaCl₂ was uniformly dispersed on the surface of expanded graphites in the block. The porosities of blocks were in the range of 0.4-0.83. The dimension of blocks was found to be more stabilized as bulk density increases. Temperature profile was govened by the reaction kinetics at the initial stage and by the external heat transfer in the long run.