The lime is a typical material for the building industry. The grinding of such material a connected with the hundreds of years of human experience. However, present activities using lime as the sorption material for exhalations show that the knowledge of the lime grinding process is very poor. Several methods as classical sedimentation, the remains on the 90- and 61-mum sieves. BET, CILAS diffraction. SEM photographs and the microstructure relieves were used to reply the question: "Where are hidden all the enormous energy requirements of the pre-grinding, the ball mills and the separators in the lime hydrate grinding circuits. when the material with its complicated micro-structure before and after grinding seems to be nearly the same?" The papa marks the basic technology outlook for the lime hydrate sorption surface enlargement. (C) 2004 Elsevier B.V. All rights reserved.