Question

Discuss the role of gypsum during the manufacturing of Ponland cement.

Answer 1

C₃A readily combines with water and liberates a large amount of heat. The added gypsum retards the dissolution of C₃A by forming insoluble calcium sulpha-aluminate 3CaO .AI₂0₃ . .xCaS0₄  .7H₂0. This reaction prevents high concentration of alumina in the cement solution which retards the early initial set of the cement.