- 期刊
Crystal Growth Rate of Calcite in a Constant-Composition Environment
方解石晶體在定組成環境下之成長速率
摘要
本文以定組成方法研究方解石晶體在流化床結晶槽中之成長動力學，所探討之操作變數包括過飽和度、酸鹼值、活性比、離子強度及表面流速。在以下操作變數之範圍內，如相對過飽和度(σ)，介於0.5與1.5間，pH值介於8.5與9.5間，離子強度介於0.004 M及0.016 M間，除表面流速外，這些變數對方解石之成長都有顯著影響。但是在離子強度介於0.016 M至0.028 M間，成長速率並無太大變化。晶體成長速率是以滴定溶液消耗速率計算而得，與酸鹼恆定方法之鈣離子消耗速率有所不同。然後將定組成法與酸鹼恆定法所得之方解石晶體成長速率作一比較。
關鍵字
無資料並列摘要
The growth kinetics of calcite crystal was studied in a fluidized-bed crystallizer using a constant-composition method. Several operation variables were investigated, including supersaturation, pH value, activity ratio, ionic strength and superficial velocity. These factors except superficial velocity are significant as far as the influence on the calcite growth rate is concerned in the range of relative supersaturation (σ) between 0.5 and 1.5, pH value between 8.5 and 9.5, ionic strength between 0.004 M and 0.016 M; however, the calcite growth rate remains constant for the ionic strength varying from 0.016 M to 0.028 M. The crystal growth rates were calculated from the consumption rate of titration volume, contrast to the decreasing rate of calcium ion used in the pH-stat method. Then the calcite growth rates were compared with those determined by the pH-stat method.