镁铬耐火材料在真空条件下的抗渣性

Slag resistance of MgO-Cr_2O_3 refractories in vacuum condition

采用真空感应炉抗渣法,研究了半再结合镁铬耐火材料在碱度分别为0.6、1.1、1.5和1.8的CaO-SiO2渣与Al2O3含量为37.98%的CaO-Al2O3渣中的抗侵蚀性,试验条件是真空度5kPa、1650℃保温25min。对侵蚀后的试样进行观察与测量,并用SEM与EDAX分析了试样的断面形貌和化学组成变化。结果发现:在CaO-SiO2渣中,随着炉渣碱度的升高,镁铬试样中的尖晶石更易于受到熔渣的侵蚀,并且尖晶石中的Cr2O3、Fe2O3被CO与钢水中的C还原为金属态的铬铁合金,试样的直接结合被破坏,侵蚀量变大。在CaO-Al2O3渣中,镁铬试样在边界层生成致密的MA尖晶石,抑制了熔渣的进一步侵蚀和Cr2O3、Fe2O3的还原,显示出较好的抗侵蚀性。

The corrosion resistances of semi-rebonded MgO -Cr2O3 refractories to CaO -SiO2 slags with basicity of 0.6,1. 1, 1.5 and 1.8 respectively and CaO -Al2O3 slag （ w（Al2O3 ） =37.98% ） were studied by slag attack method in vacuum induction furnace. The specimens were soaked into molten Slag and steel at 1650 ℃ for 25 min under 5 kPa vacuum degree. The section morphology and chemical compositions of the corroded specimens were analyzed by SEM and EDAX. The result showsthat： in CaO -SiO2 slag,the spinel of MgO -Cr2O3 refractories are more easily corroded by the molten slag with the increase of slag basicity.In addition,Cr2O3 and Fe2O3 in spinel are reduced into metallic chromium -iron alloy by CO and C in molten steel. Therefore,the direct bond structure of the specimens is destroyed and the corrosion degree becomes larger. In CaO -Al2O3 slag ,the dense MA spinel is generated at the interface of the specimen which prevents the further penetration of the molten slag and the reduction of Cr2O3 and Fe2O3, showing better slag resistance.