Magnesia is the most important refractory raw materials used mainly in the steel and cement industries. Indian magnesite (mostly of Salem and Almora origin) is a less-preferred variant amidst the harsh steelmaking conditions (tapping temperature > 1700oC and slag basicity >3) due to their tendency to form low melting phases at elevated temperature, thereby affecting the refractory properties. Impurities removal has thus become an absolute necessity for proper utilization of Indian magnesite.

Keeping in view of the above, CSIR-CGCRI has taken up a project with special attention towards the purification of impure magnesite and the production of large magnesia crystals through fusion technique. These fused magnesia aggregates can be used mainly as for the production of MgO-C, Mag-chrome and fired magnesite refractory brick –which should show better corrosion resistance.

A comprehensive analysis of the indigenous magnesite of Almora was done to generate data that would build knowledgebase for future researchers and users of the raw material. Also, an arc-melting facility of 10 Litre crucible capacity has been established, which can be used for further research on magnesite and other ceramic raw materials. After extensive trials with magnesite, the correct batch composition, sequence of addition and operating conditions has been achieved. The melting operations have been progressively improved to melt and purify larger mass (2kg) of magnetite. . MgO content of the fused magnesia increased from 83.85% to 91.81% with a significant reduction of impurities. The data generated from this study is scalable for the larger process.

Last Updated on December 4, 2020