In order to improve the properties of purging plugs and to prolong their service life,this work attempted to impregnate alumina-spinel castables for purging plugs in refining ladle with saturated magnesium chloride solution under vacuum.After being impregnated for the first time,the specimens were treated in two different ways:(1)dried at 110℃for 24 h;(2)heated at 600℃for 3 h.Then they were impregnated for the second time.All specimens were heated at 1550℃for 3 h,then the cold properties and the high temperature properties were tested according to corresponding standards.Test results were compared and analyzed.The results show that:after being impregnated,the specimen have both better cold properties and high temperature properties,the microstructure analysis result proves that it is attributed to in situ formed spinel.However,because MgO produced by MgCl2-6H20 decomposing above 527℃can hydrate and destroy specimen microstructure,which can make the properties of specimens impregnated in the second way get worse.By comprehensive consideration,the first scheme way is more suitable.
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