Abstract: Method and apparatus for obtaining finely pulverized quicklime powder having high reactivity by calcining fine limestone powder, particularly, of particle sizes 1-100 micrometers. Coarse particles of inert substance, particularly, those having diameters of 100-1500 micrometers, are fluidized with high temperature gas to form a fluidized bed, and fine limestone powder is supplied into the fluidized bed. The fine limestone powder captured by the fluidized bed is calcined therein and the resulting quicklime powder is carried away by the stream of fluidizing gas and recovered with cyclone and bag filter. Coarse limestone may be used instead of or together with the coarse inert substance particles.