Dry-type technology for recovery of fluorine, a precious resource for Japan, from exhaust gases containing hydrogen fluoride has been developed by using calcium absorbents. The gas-solid reaction properties of chlorofluorocarbon decomposition gases and calcium absorbents at low temperature were investigated with the type of calcium absorbent and the grain size as parameters. The reactive gases obtained by HCFC22 thermal decomposition, which were contain about 30% HF and about 15% HCl, were reacted with calcium carbonate or calcium oxide with grain sizes of 1-2 mm and 2-4 mm in the temperature range from 473 to 673 K. Under these conditions, the superficial velocity ranged from 4 to 6 cm/s and the space velocity (SV) from 1600 to 2300 h(-1). The fluorine recoveries with calcium carbonate and calcium oxide differed greatly according to the reaction conditions and were greatly dependent on the reaction characteristics of each absorbent. It was suggested that formation of fine pores by CO(2) generated with advance of the fluorination reaction contributed greatly to the formation of high purity fluoride. When calcium carbonate of grain size 1-2 mm was used as solid absorbent, fluorine recovery exceeded 95%. On the other hand, the maximum recovery of fluorine with calcium oxide was 80%.