Abstract
This paper reports on the effect of pH on polymorphism of calcium carbonate (vaterite) formed in the CaCl 2 -Na 2 CO 3 -H 2 O reaction system. The initial pH of CaCl 2 aqueous solution was adjusted to the initial pH 2.0–11.3 using HCl and NH 3 aqueous solution. The initial pH was 6.5 without pH adjustment. When the reaction was carried out, amorphous calcium carbonate (ACC) was formed at the early stage of the reaction and crystallized to calcite and vatrite after 3 min of stirring. Formation ratio of vaterite at this time was 60%. Single-phase vaterite was formed at initial pH 2.0–2.5. Further, focusing on the pH during ACC crystallization. When HCO 3 − ions were 80% or more during ACC crystallization, single-phase vaterite was formed.
| Original language | English |
|---|---|
| Pages (from-to) | 35-38 |
| Number of pages | 4 |
| Journal | Journal of Crystal Growth |
| Volume | 517 |
| DOIs | |
| Publication status | Published - 1 Jul 2019 |
Keywords
- A1. Crystal morphology
- A1. Crystallites
- A1. X-ray diffraction
- A2. Growth from solutions
- B1. Calcium compounds
- B1. Inorganic compounds