【作者】 廖桂华；

【导师】 蒋明学； 李柳生；

【作者基本信息】 西安建筑科技大学 ， 材料学， 2003， 硕士

【摘要】 本文通过试验探索了优质红柱石制品的生产中红柱石精矿的用量范围，其他应用的高铝原料种类及用量范围；着重研究了烧成温度、保温时间等工艺参数和锆英石、碳化硅两种添加剂对红柱石制品性能的影响；采用XRD和SEM手段分析了部分典型试样的物相组成和显微结构，探讨了矿物组成和显微结构对红柱石制品性能影响。另外，针对研制品的拟用工作条件，研究了红柱石制品受强还原气氛侵蚀的机理，以及氧化铁在该侵蚀过程中的作用。试验结果表明：（1）采用红柱石原料生产优质红柱石耐火材料时，其中红柱石精矿用量可达80％～90％，氧化铝原料用量宜在10％～16％之间。另外，引入部分预合成莫来石有利于改善制品的抗蠕变性能，并减小制品的烧成膨胀。（2）红柱石制品的性能取决于其中红柱石的莫来石化程度和制品的烧结程度，而烧成温度和保温时间对此均有较大影响。使红柱石制品在较高温度下，适当延长保温时间烧成，对其取得优良性能是必要的。（3）加入适量的锆英石细粉或碳化硅细粉，不但可以起到促进红柱石制品烧结的作用，还可在一定程度上改善其抗热震性。 红柱石制品在强还原气氛中被侵蚀损坏的机理主要表现为： （1）在700℃以下，首先发生了Boudouard反应，在制品表面和内部造成了沉碳。继而（当T＞614℃时）莫来石在碳的还原作用下产生分解，其中SiO₂被还原成SiO气体；同时，生成的SiO又与CO反应生成SiO₂和C，但该反应随着温度升高越来越困难。 （2）在1300℃埋碳保温处理时，对于高纯红柱石制品而言，发生的侵蚀反应主要是莫来石和玻璃相中的SiO₂被还原成SiO气相；而对于高铁含量红柱石制品而言，发生的侵蚀反应除了SiO₂被还原成SiO之外，还包括Fe₂O₃被还原成FeO和Fe₃O₄，进而FeO与Al₂O₃反应形成铁铝尖晶石（FeAl₂O₄），Fe₃O₄继续被还原成金属铁。 （3）上述侵蚀反应将造成红柱石制品在化学、矿物组成及显微结构方面的明显变化。主要表现为化学组成上的SiO₂含量减少，Al₂O₃含量增多；矿物组成上的莫宋石和玻璃相含量减少，高纯红柱石制品中的刚玉相和高铁含量红柱石制品中的铁铝尖晶石含量增多，以及显微结构方面呈现空洞化倾向。 （4）氧化铁对红柱石制品经受氧化还原过程的作用，还表现为其反复的固溶和脱西安建筑科技大学硕士学位论文熔会造成制品的结构受损，产生宏观裂纹，强度下降明显。而高纯红柱石制品虽然侵蚀之后结构空洞化现象较明显，但无宏观裂纹，且其强度降低的程度不大。更多还原

【Abstract】 The andalusite based refractory(hereinafter shorten toABR)with excellent properties is a kind of high-temperature material which needs developing father in China. Aiming at the production of high-quality ABR , this thesis has probed the use amount ranges of andalusite concentrates and other applied alumina raw materials. In addition, in this thesis, the influences of some technological factors, such as sintering temperature and soaking time at this temperature , and two additives, zircon and silica carbide, on the properties of ABR are studied.The mineral compositions and microstructares of some typical samples are analysed by means of XRD and SEM, and, the influences of them on the properties of ABR have been discussed. Besides, the corrosion mechanism of carbon monoxide on ABR, and the effect of iron oxide on this corrosion course have also been studied in this thesis. The results show that: (1) The use amount of andalusite concentrates should be 80%~90%, the use amount of alumina powder should be 10% to 16%. (2)The properties of ABR depend on mullitization extend of andalusiiite concentrates and its sintering extend, Whereas sintering temperature and soaking time at this temperature have remarkable influences on them. (3)Adding appropreciate amount of fine zircon power or fine silica carbide power can not only play a promotive part in sintering of ABR, but can improve its thermal shock resistance.As concerns the corrosion mechanism of carbon monoxide on ABR, it could be summed as follows: (1) At lower temperature (<700 ),the bounduard reaction (2CO-C+CO2) occurs firstly, which results in carbon deposition inside ABR and on its surface. Then mullite in the material is reduced into A12O3, SiO and CO2 by Carbon. (2) When temperature is at 1300 steadily, as far as the high-purity ABR is concerned, the corrosion reaction occurred in the material is chiefly that SiO2 in mullite and glass is reduced into SiO; as far as the ABR with high iron content is concerned, in addition to the reactions dissertated above, the corrosion reactions occurred in the material include that Fe2O3 is reduced into FeO and Fe3O4, that FeO reacts with Al2O3 to form FeAl2O4 and Fe3O4 is reduced into metallic iron subsequently. (3) The corrosion reactions discussed above will cause remarkable changes in chemicalcomposition, mineral composition and microstructure of ABR. (4) In addition, when ABR is oxidized and reduced over and again, the effects of iron oxide on the corrosion course include that it will result in the disruption of structure of ABR, the formation of macroscopic cracks, and the descent of strength of ABR.更多还原