The paper explains physical meaning of the K-parameter and the B-parameter in Heckel＇s mathematical model of ceramic powder compaction. The K-parameter quantifies the sensitivity of the powder to the pressure influence, while the B-parameter should be associated with the initial density of sample (under ＇＇the zero pressure＇＇). The conclusions were made based on an analysis of shapes and positions of compaction curves in the D-p co-ordinates. The statements will be illustrated by investigations on a few examples, whose compaction curves are adjusted by combining the fractions with defined particle size range.