Processing of refractory materials using various magnesium sources derived from Zinelbulak talc-magnesite

Abstract

Magnesia (MgO) is widely used in the production of refractory materials due to its high melting point, high thermal shock, and excellent slag resistance. The properties of refractory materials depend upon magnesia sources and processing parameters. In this work, three different magnesium sources, namely, magnesium hydroxide concentrate, magnesium carbonate concentrate, and intermediate flotation concentrate, were obtained from the Zinelbulak talc-magnesite, Uzbekistan, by causticization-hydration and flotation processes, respectively. A series of refractory materials were prepared on the basis of these magnesium sources, and their effects on physico-mechanical properties and microstructures were investigated as a function of sintering temperature, molding pressure, and the particle size of magnesium sources. The experimental results showed that a refractory material obtained from the magnesium hydroxide concentrate at 1600°C for 4 h demonstrated favorable parameters due mainly to a higher degree of contact among fine particles. The results obtained from X-ray diffraction and optical microscopy confirmed the presence of periclase and forsterite as the predominant phases in refractory specimens. The prepared refractory materials meet the requirements of the State Standards (Nos.4689-94 and 14832-96) for magnesia and forsterite refractories, respectively. It is, therefore, suggested herein that the use of different magnesium sources derived from the Zinelbulak talc-magnesite will offer the potential to provide economic benefits in the refractory industry.

Keywords

refractory materials magnesia / mechanical properties / microstructure / sintering

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