A preliminary study on preparation and properties of magnesia based clinker with zeolite and magnesite

Dead burnt magnesia is the main raw material of magnesium phosphate cement, which is widely used in road repair works. However, due to the high energy consumption and high cost in the production and preparation process of dead burnt magnesia, its application is limited to a certain extent. In this work, a magnesia based clinker containing a considerable number of magnesium oxide and magnesium silicates phase was prepared by co-firing of zeolite powder and magnesite at low temperature (1200–1300 ℃). The results show that high temperature than 1200℃ results in less free MgO. Intermediate phases 2CaO·MgO·2SiO2 formed in clinker at 1250℃ and 1300℃. The workability of the pastes made from calcined cement clinker was proved to be better than that of traditional magnesium potassium phosphate cement (MKPC). The compressive strength can reach 30 MPa after curing for 7 days. Compared with the traditional MKPC, the hydration heat of the new magnesia based cement is greatly reduced. Lower calcination temperature on the cement clinker resulted in fewer cracks and pores on the surface of magnesia based cement and denser structure of the hydration products.