Development and evaluation of Magnesium Potassium Phosphate Cement based refractory

In this work, phosphate bonded refractory was developed using magnesium potassium phosphate cement and its physical, mechanical and thermal properties were evaluated. Cement was prepared from caustic calcined magnesium oxide with addition of mono potassium phosphate. Characterisation of cement was done by XRD and SEM to examine the change in phase and morphology which occurs after hydration of magnesium potassium phosphate cement which is in the form of struvite phase. To evaluate the physical, mechanical and thermal properties, refractory samples were casted and subsequently dried and fired at temperatures range of 1300°C to 1500°C. Then the bulk density, apparent porosity and crushing strength were analysed. It was found that the properties of chemical bonded refractory are better than convectional calcium alumina cement bonded refractory.The refractory specimens sintered at 1400oC, were analyzed for thermal and mechanical properties. They exhibited better wear resistance at both room temperature and at high temperature (1000oC). Properties of calcium alumina bonded refractory were also studied and compared with those made from magnesium potassium phosphate bonding. It is observed that the developed refractories are better in terms of wear resistance and thermal expansion. This indicates that the developed magnesium potassium phosphate bonding can be a good approach for fabricating refractories where high temperature resistance and wear resistance are required.