1. Materials of Construction-Gypsum
Wikipedia.org
GYPSUM
Chapter 9
mii.org
Materials of Construction-Gypsum

2. Materials of Construction-Gypsum
Example
How much Plaster of Paris can be obtained by calcination of 1 ton of pure gypsum rock?
Ca: 40, O: 16, S:32, H:1
100 °C- 190 °C
CaSO4.2H2O CaSO4.1/2H2O + 3/2H2O
x / x=843 kg
Materials of Construction-Gypsum

3. Materials of Construction-Gypsum
Example
500 kg of a gypsum rock sample is calcined and 320 kg of pure plaster of Paris is obtained. Determine whether the gypsum rock is suitable for commercial use?
100 °C- 190 °C
CaSO4.2H2O CaSO4.1/2H2O + 3/2H2O
x / x=379.6 kg
379.6/500x100=75.9% >70%
It can be used commercially.
Materials of Construction-Gypsum