Bonding Mechanisms of Basic Refractories for RH Snorkels  

作　　者：GUO Zongqi MA Ying 

机构地区：[1]Trasteel International SA,Lugano CH-6900,Switzerland [2]RHI Magnesita(Dalian)Co.,Ltd.,Dalian 116600,China

出　　处：《China's Refractories》2020年第4期29-34,共6页中国耐火材料（英文版）

摘　　要：Magchrome bricks,as the inner lining of RH snorkels,have played a vital role in the operation of RH degassers for a long term.In chrome-free campaigns,resin-bonded,Al-containing magnesia bricks have been an alternative of magchrome bricks with a comparable performance in the last decade.It is important to have found whisker formation in the matrix of Alcontaining magnesia bricks above 1100°C and in the correlation to their high performance of RH snorkels.In this paper,the bonding mechanisms of both refractories are investigated to differentiate from other refractories.In magchrome bricks,the bonding modes of fused magchrome grains are characterized by the reactions between magnesia and chrome ore at different burning temperatures.At 1500°C,liquid forms around chromite grains.It is sucked into surrounding magnesia and a gap forms around chromite grains at 1600°C.Plenty of Fe2O3,Cr2O3 and Al2O3 have diffused from chrome ore into magnesia at 1670°C.A complete dissolution of the chrome ore takes place at 1750°C,with chromite precipitating entirely.In unburnt,Al-containing magnesia bricks,a dense network of whiskers is formed during heating,which is a prevailing bonding feature,instead of traditional particle growing and merging.It is believed that the whiskers are formed by vapoursolid mechanism since there is no liquid droplet observed at the tip of whiskers.In most stringent working conditions of RH snorkels,the bonding mechanisms are emphasized for their application,instead of chromia component.

关 键 词：magnesia-chromite brick unburnt basic brick bonding mechanism RH snorkel whisker vapour-solid mechanism 

分 类 号：TQ175.1[化学工程—硅酸盐工业]