铝热自蔓延法制备低氧高钛铁合金及表征

以金红石、钛精矿、Al为原料采用铝热自蔓延法制备出低氧高钛铁。研究相关反应体系的热力学及动力学问题,考察配料比、熔渣类型、发热剂等对铝热自蔓延过程的影响,采用XRD,SEM以及化学分析等技术对高钛铁合金进行表征。结果表明:反应体系的绝热温度大于1800K,反应能自我维持进行;Al还原TiO2反应的表观活化能为93.676kJ.mol-1,反应级数为0.01,Al还原TiO2和Fe2O3的表观活化能为300.740kJ.mol-1,反应级数为1.20;合金主要由TiFe2、TiFe以及Fe2TiO0.13等钛铁低氧固溶体相组成,夹杂相存在是导致合金中氧含量高及微观缺陷存在的直接原因;合金中钛、铝、铁、硅含量分别为:60.0%～62%、7.0%～11.0%、21.0%～25.0%以及3.0%左右;合金中的氧被有效去除,最低为1.85%。

Preparation and Characterization of High Titanium Ferrous with Low Oxygen Content by Thermit Reduction-SHS

Rutile,ilmenite and Al powder were used to prepare high titanium ferrous alloy by thermit-SHS(self-propagating high-temperature synthesis) reduction method.The thermodynamic and dynamic of the relative reaction systems were studied.The effects of charge ratio,slag type and heating agent on the thermit-SHS reduction process were investigated and the high titanium ferrous alloys were characterized by XRD,SEM and chemical compositions analysis technologies.The results indicate that the adiabatic temperatures of all reaction systems are higher than 1800 K,so all of the reactions can be kept up by self.The apparent activation energy is 93.676 kJ.mol-1 and reaction order is 0.01,the apparent activation energy for Al reducing TiO2 and Fe2O3 is 300.740 kJ.mol-1 and the reaction order is 1.20.The high titanium ferrous alloys consist mainly of TiFe2,TiFe and Fe2TiO0.13 ilmenites solid solution with low oxygen content.The oxide inclusions exist in the alloy which results directly in the high oxygen content and micro-structural defects in the alloys.The contents of titanium,aluminum,ferrous and silicon in the alloy are 60.0%-62%,7.0%-11.0%,21.0%-25.0% and 3.0% about,respectively.The lowest oxygen content in the alloy is 1.85% which is removed effectively.