SiC结合刚玉材料的抗高炉渣侵蚀性

Study on corrosion resistance of SiC bonded corundum materials to BF slag

采用电熔刚玉、Si粉和SiC粉为原料,用酚醛树脂做结合剂,混练成型后于1 450℃埋炭烧成,采用静态坩埚抗渣试验研究了烧后试样对碱度为1.1的高炉渣在1 500℃的抗渣侵蚀性。结果表明:Si与C、CO在高温下原位反应生成纤维状SiC,形成原位SiC结合刚玉材料,该材料具有良好的抗侵蚀性能,渣蚀厚度都在2.6mm以下,其中,加入8%(w)Si粉和5%(w)SiC粉的试样抗渣侵蚀性最好。通过对抗侵蚀后试样的侵蚀层、渗透层和未变层的相组成和显微结构的分析认为:(1)这种复合材料抗渣侵蚀性能良好的主要原因是熔渣难润湿的SiC自身抗渣侵蚀性较好,且原位生成的纤维状SiC穿插在刚玉骨架结构的空隙中,阻挡了熔渣的侵蚀和渗透;(2)熔渣侵蚀材料的过程是SiC先被氧化,然后其氧化产物SiO2与熔渣中的CaO和SiO2以及材料基质中的A l2O3反应生成钙长石低熔相。

In-situ SiC bonded corundum specimens were prepared using fused corundum,silicon powder and silicon carbide powder as starting materials,resin as binder,firing the pressed specimens at 1 450 ℃ under carbon embedded condition.The corrosion resistance of the specimens against blast furnace slag（basicity 1.1） at 1 500 ℃ was investigated by static crucible test method.The results indicate that：Si reacts with C and CO forming fibrous SiC at high temperature,which will further form in-situ SiC bonded corundum materials performing good slag resistance,and the corroded thickness is smaller than 2.6 mm.The specimens with 8 wt% Si and 5 wt% SiC perform the best slag resistance.Based on the investigations on phase composition and microstructure of corroded zone,penetrated zone and unchanged zone of the specimens after slag corrosion tests,it can be concluded：（1）The main reason for the good slag resistance of the composite materials is that SiC with poor wettability to blast furnace slag well intersperses in the interstices of the corundum skeleton structure,which will impede slag attack as well as slag penetration.（2）Slag corrosion behavior of the composite materials is that SiC is first oxidized forming SiO2,which reacts with CaO from slag and Al2O3 in matrix of the specimens forming low melting anorthite（CaO·Al2O3·2SiO2）.