Yüksek aluminalı refrakter çimentoların mühendislik özellikleri

Abstract

The article presents a summary of the engineering properties of High Alumina cements which exhibit excellent abrasion and corrosion resistances and improved refractory characteristics. Brief information is provided on the various uses of Calcium Aluminate (CA) cements which include many applications in refractory industry, in places subjected to severe exposures to harmful chemicals and abrasives and special structures such as dams and sewage systems. The production of CA cements can be accomplished either by sintering or by fusion processes. The latter is more common where the raw materials,mainly bauxite and limestone, are fed into an L-shaped kiln from the top and after calcination and fusion they are homogenized in the horizontal section. The mixture is cooled forming a shapeiess clinkerandgroundas CA cement without using any additions. The mineral composition of CA cement is quite different from that of portland cement. Therefore, its major compounds and their properties as well as hydration and setting processes are also explained. Heat resistance of CA cement mortars can be further enhanced by using admixtures.For instance,it can be raised up to 2000 °C by adding fused alumina. CA cements are not produced in Turkey and they are rather expensive. However, for special applications mentioned in the article their use may provide the optimum economical solution.Therefore, their properties and capabilities should be understood property.