On the Formation of Silicate Mineral in High Basicity Sinter

Abstract

The microstructures of the slag matrices in the industrial sinters with high basicity were investigated. The matrices are composed mainly of dicalcium silicate, melilite and glassy silicate. Small amounts of calcium ferrite and iron oxide, whose crystals are dendritic in many cases, are also contained. On the basis of the combinations of these minerals, the crystal-lization processes from the molten slag of the CaO-FeO-Fe₂O₃-Al₂O₃-SiO₂ system are discussed. The matrices containing dicalcium silicate as the first primary phase are observed generally throughout the sample sinters, and those containing other primary phases are not generally. The formation of the latter is considered to be originated in the maldistribution of raw materials and the delay in the homogenization of the melt. The melilite particles, the non-precipitated silicate, which is formed by the reaction of coke ash and molten slag, is found only a little.