摘要
以碳酸氢铵为沉淀剂,从氯化钴溶液中沉淀制得棒状碱式碳酸钴。采用TG-DTG-DSC热分析技术对碱式碳酸钴的热离解过程进行研究,采用X射线衍射技术对碱式碳酸钴在不同煅烧温度下的热离解产物进行物相分析,采用扫描电镜观察碱式碳酸钴及其在700℃的煅烧产物Co3O4的形貌特征。结果表明,在此实验条件下,碱式碳酸钴在450℃煅烧以及保温3 h的热离解产物中CoO的质量分数依然高达50.5%,碱式碳酸钴完全离解为Co3O4的温度高于359.5~421.1℃的热分析测量值;700℃煅烧可得到单一相成分的Co3O4;850℃煅烧,Co3O4发生离解,热离解产物中CoO的质量分数高达47.93%,这一离解温度低于Co3O4热离解最低温度为910~920℃的热力学理论预测值。要制备单一相成分的Co3O4,必须严格控制其前躯体的煅烧离解条件。Co3O4产物对碱式碳酸钴具有良好的形貌继承性,因此通过控制Co3O4粉末前驱体的制备条件可以实现对Co3O4粉末形貌的有效控制。
Rod-like basic cobalt carbonate（BCC） was prepared by reaction-precipitation method using CoCl2·6H2O and NH4HCO3 as starting materials.The thermal dissociation process of the prepared BCC was studied by TG-DTA-DSC thermal analysis technology.X-ray diffraction technology was used in the study of the phase composition of the thermal dissociation products of BCC calcined at different temperatures.Scanning electron microscopy was used in the observation of the morphologies of the BCC and its dissociation product at 700 ℃,i.e.Co3O4.It is shown that,after the calcining of the BCC at 450 ℃ for 3 h,CoO still existed in the product with a mass fraction as high as 50.5%,indicating that the complete dissociation temperature of BCC to Co3O4 must higher than that of the predicted value of 359.5~421.1 ℃ by thermal analysis.Pure Co3O4 can be prepared by calcining of the BCC at 700 ℃.Calcining of the BCC at 850 ℃ which is lower than the predicted lowest temperature,i.e.910~920 ℃ by thermodynamics for the dissociation of Co3O4 to CoO,the mass faction of CoO dissociated from Co3O4 is as high as 47.93%.Therefore,for the preparation of pure Co3O4,the calcining condition must be controlled strictly.Based on the observed morphology inheritance of Co3O4 to its precursor BCC,it can be deduced that the morphology of Co3O4 can be controlled effectively through the controlling of its precursor.
出处
《粉末冶金材料科学与工程》
EI
2010年第6期679-684,共6页
Materials Science and Engineering of Powder Metallurgy
基金
国家科技重大专项(2009ZX04012-032)
国家自然科学基金资助项目(51074189
50823006)
湖南有色集团-中南大学有色研究基金项目(Y2008-01-008)
湖南省科技计划重点项目(2010FJ2006)
高等学博士学科点专项科研基金项目(20100162110001)
关键词
碱式碳酸钴
四氧化三钴
热离解
形貌继承性
basic cobalt carbonate
Co3O4
thermal dissociation
morphological inheritance
