以月球资源原位利用为目的,研究了在冰晶石熔盐介质中铝热还原钛铁矿制备铝钛铁合金。热力学计算表明,在960℃,铝热还原钛铁矿的相关反应在热力学上可以自发进行。在组成(质量分数,下同)为47.14%NaF-42.86%AlF3-10%FeTiO3的960℃冰晶石介质中进行铝热还原,研究还原剂用量和还原时间对合金产物的影响。还原产物用XRF、XRD、SEM和EDS进行分析。结果表明,合金产物中有Al、Ti、Fe和少量Si,产物的主要物相是Al3Ti。随着铝用量的增加,合金产物中Ti的含量逐渐减少,而Fe的含量逐渐增加;随着反应时间的延长,产物中Al3Ti的含量增加。在冰晶石熔盐体系中进行铝热还原2 h、还原剂用量为理论用量3倍时,铝中钛含量最高可达18.82%。低还原剂用量和较长还原时间在冰晶石熔盐介质中还原钛铁矿,可实现Ti/Fe分离;还原反应为原子态的铝还原溶解为离子态的Ti^4+得到Al-Ti合金。
Focused on in-situ utilization of lunar resources, we studied the preparation of aluminum alloy by aluminothermic reduction of ilmenite in molten cryolite media. The thermodynamics calculation shows that the standard Gibbs free energy change of aluminothermic reduction of ilmenite is negative in the temperature range 0-1500 ℃. The effects of reductant amount and reaction time on the aluminothermic reduction of ilmenite in 47.14wt%NaF-42.86wt%AlF3-10wt%%FeTiO3 at 960 ℃ were studied. The results obtained by XRF, XRD, SEM and EDS analysis indicate that the products mainly contain Al, Ti, Fe, and a little Si, and the main phase of the product is Al3Ti. With the increase of reductant amount, the content of Ti in alloy products decreases, while the content of Fe in alloy products increases. In addition, the content of Al3Ti increases with the increase of reaction time. The highest content of Ti in the alloy obtained by aluminothermic reaction at 960 ℃ for 2 h using three times reductant amount of theoretical amount is up to 18.82 wt%. Fe and Ti can be separated in FeTiO3 aluminothermic reduction using lower reductant amount and higher reduction time. The FeTiO3 aluminothermic reduction reaction takes place between the dissolved Al atom and dissolved FeTiO3 in the cryolite melt.