부산대학교 도서관

Crystallization study of calcium sulfate dihydrate was studied under conditions of scales formation using pure chemicals and at low salinity. Calcium chloride and sodium sulfate were mixed in deionized water, and the conductivity of the reaction mixture was measured at different time periods to determine the induction time of gypsum crystal formation. Induction time was measured under different high supersaturation ratios (SRs) ranging from 5.9 to 7.0. Using crystallization equations that relate induction times with SRs, the free energy barrier and critical nuclei radius were calculated with and without the addition of a scale inhibitor (tri-sodium phosphate, TSP). The nucleation rates at SR of 5.9 are 7.6 × 1026 nuclei/cm3 · s and 2.3 × 1026 nuclei/cm3 · s with and without TSP addition, respectively. The surface energy increases with TSP compared to the baseline (without TSP). Numbers of molecules required for the formation of stable nucleus are calculated to be from 15 to 22 molecules depending on supersaturation ratios and presence or absence of TSP. [ABSTRACT FROM AUTHOR]