Product Details
Calcium oxide (CaO, CAS No. 1305-78-8), commonly referred to as lime, quicklime, burnt lime, or calx, does not exist naturally because it readily reacts with water to form hydrated lime and with carbon dioxide to form limestone. It is obtained by calcining calcium carbonate materials such as limestone or oyster shells at temperatures ranging from 1,700 to 2,450°C.

Calcium oxide Chemical Properties
Melting point | 2570 °C |
Boiling point | 2850 °C (lit.) |
Density | 3.3 g/mL at 25 °C (lit.) |
Bulk density | 800-1200kg/m3 |
Refractive index | 1.83 |
Fp | 2850°C |
Storage temp | no restrictions |
Solubility | 1.65g/l Risk of violent reaction |
Form | powder |
Color | White to yellow-very slightly beige |
Specific Gravity | 3.3 |
PH | 12.6 (H2O, 20℃)(saturated solution) |
Odor | wh. or gray cryst. or powd., odorless |
Water Solubility | REACTS |
Sensitive | Air & Moisture Sensitive |
Crystal Structure | Cubic |
Crystal system | Cube |
Merck | 14,1686 |
Space group | Fm3m |
Lattice constant | a/nmb/nmc/nmα/oβ/oγ/oV/nm30.47760.47760.47769090900.1089 |
Dielectric constant | 2.2(Ambient) |
Exposure limits | ACGIH: TWA 2 mg/m3 OSHA: TWA 5 mg/m3 NIOSH: IDLH 25 mg/m3; TWA 2 mg/m3 |
Stability | Stability Stable, but absorbs carbon dioxide from the air. Incompatible with water, moisture, fluorine, strong acids. |
InChIKey | ODINCKMPIJJUCX-UHFFFAOYSA-N |
CAS DataBase Reference | 1305-78-8(CAS DataBase Reference) |
NIST Chemistry Reference | Calcium monoxide(1305-78-8) |
EPA Substance Registry System | Calcium oxide (1305-78-8 |

Product Usage
Lime is widely used in various industries such as metallurgy, flue gas desulfurization, construction, mining, papermaking, and water treatment. In iron ore refining, calcium oxide plays a key role in impurity removal by reacting with compounds like silicates, phosphates, and sulfates present in the ore to form slag.
