Gypsum powder

Most gypsum is calcined and used in the manufacturing of plaster products. Wallboard and plaster requires gypsum contents greater than 85%, although producers prefer a minimum of 94–95% along with whiteness in color. The major consumers of the gypsum at present are cement industry. By weight about 4% to 6% gypsum in crushed condition is utilized in portland cement manufacture after mixing with cement/clinker. Gypsum acts as a retarder and controls the setting time of cement.