A Comprehensive Study of Indian Magnesites as Refractory Material

Abstract

The investigation includes six bulk samples of magnesite from Salem, Mysore, Ajmer and Almora to represent a comprehensive account of the indigenous resources. They constitute two distinct types: cryptocrystalline and crystalline. The different deposits have been outlined comparatively in their modes of occurrence and origin. Mineralogical data include petrography, dta and x-ray analysis; they are in close correspondence with the chemical compositions of the different samples. Studies on sintering at temperatures between 1500° and 1700°C indicate that the Indian magnesites can be properly dead-burnt around 1650°C. Girechchina magnesite containing about 35% dolomite may be calcined inert at about 1550°C. The segregation of matrix, and the role of iron and other impurities during calcination have been discussed. Magnesite and chrome-magnesite refractories made from each type have been found to develop satisfactory properties, in general, and particularly with respect to refractorieness underload, and volume stability at 1700°C. Dicalcium silicate bonded refractories from Girechchina magnesite indicate higher refractoriness underload and cold crushing strength.