【摘要】 烧结法合成铁铝尖晶石需要控制适当的气氛,以保证氧化亚铁(FeO)处在其稳定存在温度与氧分压条件下。以往通过对不同氧分压下Fe2O3-Al2O3相图以及1 500℃时FeO-Fe2O3-Al2O3三元系统等温截面图的分析,说明氧分压越低越有利于铁铝尖晶石的合成,而且Fe3O4与FeAl2O4的固溶度随着氧分压降低以及铁铝尖晶石含量增加迅速降低。热力学计算表明:在氧分压为0.5 Pa高纯氮气气氛条件下,FeO在1 473～2 160℃范围内能够稳定存在,在此温度范围烧结可以合成铁铝尖晶石。实验证明:以Fe2O3粉和Al2O3粉为原料,配料时需要引入一定量还原碳粉以消耗Fe2O3分解产生的氧气,当烧结温度高于1 500℃时,所有的铁源都转化为铁铝尖晶石相。由于烧结温度较高,目前仅限于实验室合成。更多还原

【Abstract】 The synthesis of hercynites by sintering method needs to control a suitable atmosphere,and make sure of ferrous oxide(FeO) at the temperature and O2 partial pressures which it can stably exist.By analyzing the phase equilibria about the system Fe2O3-Al2O3 in different O2 partial pressure and the isothermal section of the system FeO-Fe2O3-Al2O3 at 1 500 ℃,the results show that the lower O2 partial pressure is beneficial for synthesizing hercynite.The solid solubility of Fe3O4 and FeAl2O4 reduced rapidly with the decreasing of O2 partial pressure and increasing of the content of hercynite.Thermodynamics calculation indicates that FeO can stably exist at the temperature between 1 473 ℃ and 2 160 ℃ under a high purity N2 atmosphere which the O2 partial pressure is 0.5 Pa,and hercynites can be synthesized at this condition.The test proves that if the Fe2O3 powders and Al2O3 powders are used as raw materials,it need add a definite mass of carbon powders to consume the oxygen decomposed by iron oxide,and all ferrous oxides change to hercynites when the temperature is higher than 1 500 ℃.Such a high sintering temperature makes the reaction limited in the laboratory.更多还原