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Abstract: Magnesite-chrome aggregates have been prepared from friable chrome ore and magnesia of different reactivity in the presence of an additive, ZrO2. Two types of batch compositions using sintered magnesia, caustic magnesia and chrome ore have been selected for preparing mag-chrome composites. The batch consisting of sintered magnesia and friable chrome ore (SMC) was vibromilled for 8h, whereas caustic magnesia compositions were added directly to a vibromilled chrome ore (CMC) and mixed in a fluidized bed mixer. Additions of 1–5wt.% ZrO2 were made to the batches. Firings were carried out between 1700 and 1750°C with 2h soaking. Aggregates were characterized by evaluating densification, hot modulus of rupture and microstructure. The reactivity of magnesia was found to play an important role in the final properties of samples. Introducing less reactive sintered magnesia improved all the properties of the aggregates. ZrO2 was found to be a good sintering aid in the magnesite-chrome composites. [Copyright &y& Elsevier]

Sintering of lime was carried out in the presence of V2O5 by a single firing process. A pure limestone was crushed, mixed with 1, 2 and 4 wt.% V2O5, pelletised and fired between 1550 and 1650 °C. The sintered lime was evaluated by bulk density, apparent porosity, microstructure, hydration resistance and hot modulus of rupture (HMOR) at 1300 °C. Incorporation of V2O5 forms liquid phase with lime at elevated temperature and influences the densification process by liquid phase sintering. As a result bulk density of sinters improved and they become more hydration resistant due to the larger grain size of the lime phase. The hot strength increased up to a certain temperature followed by deterioration because of the pressure of higher amount of liquid phase. [Copyright &y& Elsevier]