关键词: 橄榄石, 中间包, 镁质涂抹料, 抗渣性

Abstract: To enhance the durability and reduce the cost of magnesia-based coatings for continuous casting tundishes,magnesia-based tundish coating materials were prepared using olivine,medium-grade magnesia clinker,and silica fume as the main raw materials,with magnesium sulfate heptahydrate as the binder.The effects of olivine additions (38%,45%,53%,61%,and 69%,by mass) on the phase composition,physical properties,and slag resistance of the coatings were researched.The results show that:(1)after heat treatment at 1 550 ℃,the main crystalline phases of the samples are periclase,forsterite,and stishovite.With the increasing olivine addition,the periclase content gradually decreases,while the forsterite and stishovite contents gradually increase;(2)at high temperatures,the magnesium ferrite and forsterite formed in the matrix exert a filling effect,leading to an increase in the bulk density and a decrease in the apparent porosity of the samples after heat treatment;(3)the expansive effect associated with the oxidation of FeO derived from the decomposition of fine olivine particles,coupled with the filling and strengthening effect of magnesium ferrite and forsterite on the matrix,results in unstable variation trends of the permanent linear change on heating and the cold compressive strength of the samples in different stages;(4)when the olivine addition is 61%,the coating exhibits the optimal slag resistance after being heat-treated at 1 550 ℃.

Key words: olivine, tundish, magnesia-based coatings, slag resistance