Bonding Mechanisms of Basic Refractories for RH Snorkels

• 作者: GUO Zongqi MA Ying
• 来源期刊: 中国耐火材料（英文版）
• 年，卷（期）: 2020,（4）
• 页码范围: 29-34
• 页数: 6页
• 语种: 英文
• DOI: 10.19691/j.cnki.1004-4493.2020.04.006

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 Al-containing magnesia bricks above 1 100 ℃ 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 1 500 ℃,liquid forms around chromite grains.It is sucked into surrounding magnesia and a gap forms around chromite grains at 1 600 ℃.Plenty of Fe2O3,Cr2O3 and Al2O3 have diffused from chrome ore into magnesia at 1 670 ℃.A complete dissolution of the chrome ore takes place at 1 750 ℃,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 vapour-solid 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.