Uranium ingot is produced by metallothermic reduction of uranium tetrafluoride using magnesium or calcium as reductant. Presence of oxygen containing compounds viz. uranyl fluoride and uranium oxide in the starting uranium fluoride has a significant effect on the firing time, final temperature of the charge, slag-metal separation and hence the metal recovery. As reported in the literature, the maximum tolerable limit for uranyl fluoride in the UF₄ is 2.5 wt% and limit for uranium oxide content is in the range 2–3 wt%. No theoretical or experimental basis is available till date for these limits. Analyses have been carried out in this study to understand the effect of UO₂F₂ concentration in the starting fluoride on the final temperature of the products and thus the reduction characteristics. UF₄ having uranyl fluoride concentration, less than as well as more than 2.5 wt%, have been investigated. Thermodynamic calculations have been carried out to arrive at a general expression for the final temperature attained by the products during calciothermic reduction of UF₄. Finally, an upper limit for the oxygen containing impurities has been estimated using the CaO–CaF₂ phase diagram.

铀锭是通过使用镁或钙作为还原剂对四氟化铀进行金属热还原而制得的。存在含氧化合物，即。起始氟化铀中的铀酰氟和铀氧化物对燃烧时间，炉料的最终温度，炉渣-金属分离以及金属回收率都有重要影响。如文献报道，UF _4中铀酰氟的最大容许限量为2.5 wt％，氧化铀含量的极限为2-3 wt％。到目前为止，尚无有关这些限制的理论或实验依据。在这项研究中进行了分析，以了解UO ₂ F _2的作用起始氟化物的浓度取决于产物的最终温度，因此具有还原特性。已经研究了具有小于和大于2.5重量％的铀酰氟浓度的UF ₄。进行了热力学计算，得出了在UF _4的热还原过程中产品所达到的最终温度的一般表达式。最后，使用CaO–CaF ₂相图估算了含氧杂质的上限。