Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第21卷    第7期    总第148期    2011年7月

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文章编号:1004-0609(2011)07-1770-07
草酸镍钴固溶体的制备与鉴别
湛 菁,岳建峰,张传福,周涤非

(中南大学 冶金科学与工程学院,长沙 410083)

摘 要: 以可溶性氯化镍、氯化钴和草酸或草酸铵为原料,氨水为pH值调节剂,采用液相共沉淀法合成草酸镍钴共沉淀产物,借助X射线衍射(XRD)、热重−差热分析(TG-DTA)和扫描电镜(SEM)对共沉淀产物进行表征,并将结果与机械混合物进行比较。结果表明:在共沉淀过程中,当溶液pH≤5.0时,钴离子易进入草酸镍晶格中形成置换固溶体,得到的共沉淀产物为草酸镍钴单相固溶体,其热分解行为明显不同于具有相同配比的机械混合物;当pH>5.0时,镍离子和钴离子与草酸根离子的共沉淀过程为分步沉淀,得到的共沉淀产物为组分分布均匀的复杂混合物,而非单相固溶体。

 

关键字: 草酸镍钴;固溶体;共沉淀产物;分步沉淀;机械混合物

Preparation and identification of solid solutions of Ni-Co oxalates
ZHAN Jing, YUE Jian-feng, ZHANG Chuan-fu, ZHOU Di-fei

School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China

Abstract:The Ni-Co oxalate coprecipitates were synthesized by liquid coprecipitation reaction using soluble nickel chloride, cobalt chloride and ammonium oxalate or oxalic acid as raw material and ammonia as pH value regulator. The coprecipitates were characterized by X-ray diffractiometry (XRD), scanning electron microscopy(SEM) and thermogravimetry-differential thermal analysis(TG-DTA), and the results were compared with those of mechanical mixtures. The results show that when pH≤5.0, the cobalt ion enters the lattice of nickel oxalate and forms a substitution solid solution. The obtained coprecipitate is a single-phase solid solution with characteristics which exhibit distinctly different thermal decomposition behavior from those of the mechanical mixture with the same stoichiometry. However, when pH>5.0, the coprecipitation process of nickel ions, cobalt ions and oxalate ions is a fractional precipitation process, and the obtained coprecipitate is a complex mixture with uniform component distribution, not a single-phase solid solution.

 

Key words: Ni-Co oxalate; solid solution; coprecipitates; fractional precipitation; mechanical mixtures

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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