Studies on Synthesis and Characterization of Magnesia Based Refractory Aggregates Developed from Indian Magnesite

Manas Kamal Haldar,Arup Ghosh,Chandrima Ghosh

doi:10.4236/msce.2014.210001

Abstract

The present work intends to study the properties of magnesia based refractory aggregates developed from Indian magnesite by changing lime/silica ratio. The material has been sintered in the temperature range of 1550C - 1700C. The sintered samples are characterized in terms of bulk density, apparent porosity, true density, percentage densification, mechanical, thermo-mechanical properties like cold modulus of rupture, hot modulus of rupture and thermal shock resistance and structural properties by XRD. The developed microstructures at different temperatures are studied through FESEM study and compositional analysis of the developed phases is done by EDX study.

Highlights

Magnesia refractories are prepared in India mainly from naturally occurring magnesite
This is due to the fact that Indian magnesite is rich in impurities, mainly SiO2, Fe2O3, CaO which form low melting phases at elevated temperature causing poor refractory properties, e.g. high temperature strength, corrosion resistance
Physical & Physico-Chemical Properties Figure 1 shows the effect of sintering temperature on the bulk density (BD) and apparent Porosity (AP) of the sintered samples

Summary

Introduction

Magnesia refractories are prepared in India mainly from naturally occurring magnesite. Though India has vast resources of natural magnesite, the refractory industries are mostly dependent on the imported magnesia. This is due to the fact that Indian magnesite is rich in impurities, mainly SiO2, Fe2O3, CaO which form low melting phases at elevated temperature causing poor refractory properties, e.g. high temperature strength, corrosion resistance. One of the most important & critical parameters in magnesia refractory is CaO/SiO2 ratio [2] which significantly affects the formation of low melting phases In this background, an attempt has been made to synthesis and study the properties of magnesia based refractory aggregates (by changing the CaO/SiO2 ratio) developed from lean grade Indian magnesite.

Experimental

Characterization of Sintered Aggregates

Conclusion