草酸铌热分解过程研究

合成了水合草酸铌，并利用元素分析法、X射线衍射（XRD）分析法、傅立叶变换红外光谱法和热重分析法对其进行了表征，明确了草酸铌的结构与组成。根据元素分析法和XRD法的分析结果，确定草酸铌的分子式为NH4·NbO（C2O4）2（H2O）2]·3H2O。利用热重分析法和不同温度下草酸铌分解产物的红外光谱图，研究了草酸铌的热分解过程。结果表明，其热降解分3个步骤进行：第一阶段（30-200℃）失重百分率为21．81％，为所含水的失重过程。第二阶段（200-330℃）失重百分率为42．40％，为草酸铌的主要热分解过程，归属于NH4^＋和草酸根离子的分解。第三阶段（550～630℃）失重百分率为4．87％，失重物质为二氧化碳。草酸铌的热分解剩余产物为百氧化二铌。

Study on thermal decomposition process of niobium oxalate

Hydration niobium oxalate was synthesized, and was characterized by elemental analysis, X-ray difractometry （XRD）, Fourier transform infrared spectrometry （FTIR）, and thermal gravimetric analysis （TGA） ; the structure and composition of niobium oxalate were made clear. The molecular formula of niobium oxalate was defined as NH4 ＊NbO（C2O4）2（H2O）2]· 3H2O by elemental analysis and XRD. The thermal decomposition process was investigated using TGA and IR spectra of products of niobium oxalate decomposed at different temperature. It was shown that the thermal decomposition process occured in three steps. In the first step （30-200℃）, the weight loss percentage was 21.81%, and the major lost material was water. In the second step （200-330℃）, the weight loss percentage was 42.4%, NH4^＋ and oxalation were decomposed, and it was the main decomposition process. In the third step（550-630℃）, the weight loss percentage was 4.87%, the lost material was carbon dioxide, and the thermal decomposition residue was noibium pentoxide.