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在真空炉中(30~40 Pa)1273 K下,将物料放入螺纹密封的石墨坩埚中进行不同时间下的还原反应。本文采用热力学分析及X射线衍射、扫描电子显微镜及能量弥散X射线谱等方法与手段,系统研究了金属钙(Ca)与反应器中的氧气(O2)、氮气(N2)、二氧化钛(TiO2)的反应和还原时间及还原产物的预处理对得到金属钛粉(Ti)的影响。通过热力学研究,在温度低于钙的熔点(1115 K)时,密封容器内的O2与Ca的反应及N2与Ca的反应满足反应发生的热力学条件。当温度达到1273K时,Ca的饱和蒸气压p*≈p系,有利于整个气固反应进行。实验研究表明,在还原反应发生前,反应器内的O2,N2与Ca反应完全。将在1273 K下还原时间为4 h得到的还原产物在酸洗前真空挥发处理还原产物表面大量的Ca时,金属单质Ti再次被氧化成低价氧化物,最终得不到金属Ti粉。将反应时间延长至6 h时,酸洗过滤后得到形状不规则、纯度达到98.64%的Ti粉。
In a vacuum furnace (30 ~ 40 Pa) at 1273 K, the material was placed in a screw-sealed graphite crucible for reduction reaction at different times. In this paper, the effects of metal Ca (Ca) and the reactor on oxygen (O2), nitrogen (N2), titanium dioxide (TiO2) were systematically investigated by means of thermodynamic analysis and XRD, SEM and energy dispersive X-ray spectroscopy. Of the reaction and reduction time and the reduction of the pretreatment of the metal titanium powder (Ti). Thermodynamic studies show that the reaction of O2 with Ca and the reaction of N2 with Ca in a sealed container satisfy the thermodynamic conditions of the reaction at a temperature below the melting point of calcium (1115 K). When the temperature reached 1273K, the saturation vapor pressure of Ca p * ≈ p Department, is conducive to the entire gas-solid reaction. Experimental studies show that before the reduction reaction occurs, the reaction of O2, N2 and Ca in the reactor is complete. When the reduction product obtained after 4 h reduction at 1273 K was subjected to vacuum evaporation of a large amount of Ca on the surface of the reduced product before pickling, the metal elemental Ti was oxidized to a lower oxide again and finally the metal Ti powder was not obtained. When the reaction time was prolonged to 6 h, the Ti powder with irregular shape and purity of 98.64% was obtained after pickling filtration.