Continual production manner null of aruhua die semi- water

摘要

PURPOSE:To continuously perform mass production alpha-type hemihydrate gypsum having stable quality by making supplying of crystallization medium agent swingingly vary little by little and regularly to pressurized hydrothermal reaction tank receiving dihydrate gypsum slurry. CONSTITUTION:Dihydrate gypsum slurry and crystallization medium agent are continuously supplied to flow-type pressurized hydrothermal reaction tank heated at a temperature below 100 deg.C and the dihydrate gypsum is dissolved in the reaction tank and simultaneously alpha-type hemihydrate gypsum is made to crystallize in the presence of crystallization medium agent, then slurry of alpha-type hemihydrate gypsum crystal is continuously taken out from the reaction tank. In said process, large and small two values B and C of weight per unit time of the crystallization medium agent supplying the reaction tank are fixed and supplying amount of the crystallization medium agent is controlled with periodically repeating B/A and C/A to afford the aimed hemihydrate gypsum.