High-quality burnt gypsum is made in Russia alongside ordinary gypsum. This gypsum is obtained by heating gypsum dried with saturated steam under pressure 1,2 atm. within 5-8 hours, followed by drying at 100 ° C.
C. on. blown plaster is approx 2,4, slow-setting cement gypsum - 2.7-2.9.
C. obj. cement plaster is 1,5 — 1,7.
Building gypsum and high-strength building gypsum hardens very quickly, hydraulic plaster slowly.