Calcination: The Powdered gypsum is heated to get rid of water molecules, producing various varieties of plaster based on the temperature and length of heating. Quite commonly it is actually shaped through the hydration of anhydrite by surface waters and groundwaters, and, As a result, several gypsiferous strata grade downward https://www.propanraya.com/id/produk/eco-gypsum-ee-4050