SYNTHESIS OF DISK-LIKE CALCIUM-CARBONATE .2. EFFECT OF VARIOUS ETHYLENEDIAMINE COMPOUNDS ON THE CARBONATION OF BASIC CALCIUM-CARBONATE AND MECHANISM OF DISK-LIKE CALCIUM-CARBONATE SYNTHESIS

The addition of straight chain polyamines such as triethylenetetramine , tetraethylenepentamine, pentaethylenehexamine and 1,4-diaminobutane in the course of carbonation of basic calcium carbonate promoted the f ormation of disk-like vaterite of 1-1.5 mu m in diameter and 0.1-0.2 m u m in thickness, On the other hand, cyclic polyamines such as piperaz ine, 1-(2-aminoethyl) piperazine and 1,4-diazabicyclo [2, 2, 2] octane , and branching polyamine such as 2,2-dimethylpropylene, promoted the formation of spindle-like calcite. Only polyamine in which N-N distanc e is 0.3 nm or its integral multiple, promoted formation of the disk-l ike calcium carbonate. Hexagonal of basic calcium carbonate once disso lved in aquarious media and the disklike calcium carbonate formed.