作者：AKIRA YOSHIDA;TAKASHI NEMOTO;TOSHIICHI IWAMOTO;

作者单位：Ube Material Industries, Ltd

刊名：Journal of the Technical Association of Refractories

ISSN：0285-0028

出版年：2007-01-05

卷：27

期：1

起页：45

止页：49

分类号：TQ175

语种：英文

关键词：

内容简介

The performance quality of magnesia clinker has been significantly improved with regard to slag corrosion resistance through purification and densification due to reduction in impurity content. Recently the demand for magnesia clinker is increasing for use in monolithic refractories as well as the raw material for shaped refractories. High hydration resistance is strongly desired as an essential property of magnesia clinker. Hydration is a serious problem for monolithic refractories and, in particular, for castable refractory materials that contain magnesia fine powders that are easily hydrated due to high moisture vapor pressure present during the drying stage after installation. The hydration resistance of magnesia fine powder is a vitally important issue in alumina-magnesia system castable refractories. In general, alumina-magnesia system castable refractories are composed of 90 to 95 mass percent alumina aggregate, 5 to 10 mass percent magnesia fine powder and a small amount of alumina cement. The raw materials are kneaded with 5 to 10 mass percent water and the mixture is poured, cured and dried in the installation process. Magnesia raw material is wet with moisture during the kneading, pouring and curing stages and is exposed to high moisture vapor pressure during the drying stage. In a previous paper the authors reported that the hydration resistance of magnesia clinker was significantly improved by increasing its B_2O_3 content. This was a result of an investigation using a water submergible autoclave test and considering the reaction between water and magnesia clinker as a method to evaluate the hydration resistance of magnesia clinker. However, the B_2O_3 component in magnesia clinker has a reputation for playing a role in the marked deterioration of the hot strength of refractory materials. The authors therefore investigated the hydration resistance characteristics of magnesia clinker with high B_2O_3 content and the effect of B_2O_3 content in magnesia fine powder on the properties of refractory materials. In particular, this paper describes the effects on alumina-magnesia castable refractory materials made with high B_2O_3 content magnesia clinker that was manufactured in actual rotary kiln.