合成草酸亚铁的反应时间对组成的影响

采用硫酸亚铁铵和草酸溶液在酸性介质条件下合成含有结晶水的草酸亚铁。通过优化实验条件、定性产物及组成的测定,实验结果表明,加热反应时间为120 min时,合成样品的结晶水的个数与理论值非常接近,即合成样品为FeC2O4·2.01H2O,且产率为97％其中样品中Fe3+的质量分数为0．28％。TG—DTA分析结果表明, 草酸亚铁分解是由脱水和分解两部分组成的,样品属于二水化合物。从200℃开始,草酸亚铁开始分解,到300℃完全分解为氧化亚铁、一氧化碳和二氧化碳,失重率达56．5％。这主要是由于在氧气中氧化亚铁不稳定,会有少量三氧化二铁生成。由此可见,自制的草酸亚铁可以作为合成磷酸亚铁锂的原材料,可满足其电化学性能的要求。

Effect of Reaction Time on the Composition of Ferrous Oxalate

The ferrous oxalate with crystal water was prepared with ferrous ammonium sulfate and oxalic acid in acid medium. Through optimizing the experiment conditions, qualitative and compositional analyzing for product, the results of experiment show that the number of crystal water is agree with the theory value, namely the molecular formula of the particle is FeC2O4· 2. 01H2O. The yield is 97% and the mass fraction of ferric ion in the sample is 0. 28% when the heating reaction time is 120 minutes. Thermal gravimetric analysis indicates that the products decomposition is composed of dehydration and decomposition, and the products are the dihydrate. From 200 ℃ , the ferrous oxalate starts to decompose, when the temperature is 300 ℃ , the products are ferrous iron, carbon monoxide, carbon dioxide,and the weight loss is 56. 5% . Because the ferrous iron in oxygen is unstable, small amount ferric oxide is formed. Therefore, the self - made ferrous oxalate can be used to prepare the lithium iron phosphate and requirement of its electrochemical properly is satisfied.