电磁场作用下高铁渣对MgO-C耐火材料的侵蚀

摘要

电磁场会促使熔渣中的铁、锰离子与MgO-C耐火材料反应形成锰掺杂镁铁尖晶石相,为进一步研究锰掺杂镁铁尖晶石的生成形貌及特征,采用Fe2O3质量分数为53.62％、CaO与SiO2质量比为0.8的高铁渣,分别在有、无电磁场环境下,对碳质量分数为14％的MgO-C耐火材料进行渣蚀试验.结果表明:感应炉存在电磁场,使熔渣中部分Fe2 +/Fe3+与镁砂中Mg2+发生置换形成镁铁尖晶石,其含有少量Mn2+离子；镁铁尖晶石中铁含量从渣蚀层到渗透层急剧降低,锰含量几乎维持不变；侵蚀后试样渗透层较明显.电阻炉无电磁场,则侵蚀后试样没有形成镁铁尖晶石,熔渣中Si、Ca渗透到方镁石晶格中,形成钙镁榄橄石低熔相,将镁砂溶解到熔渣中；渣蚀层有明显的MgAl2O4生成.%Electromagnetic field can promote the reaction between the Fe/Mn ions in molten slag and MgO-C refractories forming Mn-doped MgFe2O4 spinel. In order to further study the morphology and characteristics of Mn-doped MgFe2O4 spinel,the experiments were carried out in medium-frequency induction furnace and resistance furnace,respectively. MgO-C refractories containing 14 mass% carbon and Fe^O-rich slag containing 53.62 mass% Fe2O3 and with 0.8 of mass ratio of CaO to SiO2 were used. The results show that in induction furnace with electromagnetic field (EMF) ,some Fe2+/3+ in the slag replace Mg2+ in magnesia forming MgFe2O4 spinel,which contains a small amount of Mn2+. The iron content in Mn-doped MgFe2O4 spinel decreases dramatically from the corrosion zone to penetration zone,while the manganese content in the spinel remains unchanged. The penetration layer in the slag line under EMF is obvious. While in the resistance furnace without EMF,there is no MgFe2O4 spinel existing in corroded specimens. The cations of Si and Ca in the slag penetrate into the crystal lattice of periclase to form low melting phases of monticellite (CaMgSiO4),which makes magnesia dissolve in the slag. MgAI2O4 spinel is formed significantly in the corrosion layer.