(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 针对草酸盐配位共沉淀−热分解还原法制备超细铁镍合金粉过程中Fe2+-Ni2+-NH3-NH4+-C2O42--H2O体系的溶液平衡建立热力学分析模型，并根据模型进行相关计算，揭示反应体系中各物质随pH值、氨及草酸浓度的变化关系。结果表明：溶液中的Fe主要以[Fe(C2O4)n]2−2n络合物形式存在，而铁氨络合物含量很低。当氨含量较低时，溶液中的Ni主要以[Ni(C2O4)n]2−2n存在；氨含量较高时，在酸性条件下，溶液中的Ni主要以[Ni(C2O4)n]2−2n存在，在碱性条件下，则主要以[Ni(NH3)n]2+存在。低pH值下，Ni的沉淀率较Fe的高，而高pH值下，Ni的沉淀率则较Fe的低。
关键字: 铁镍合金；溶液平衡；络合；氨；草酸；pH值
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The thermodynamics model of the precipitation-coordination equilibrium in Fe2+-Ni2+-NH3-NH4+-C2O42−-H2O system was established and the calculation of the model was carried out. The relationships of each substance in solution with pH value, ammonia and oxide acid were revealed. The results show that, Fe in solution exists as [Fe(C2O4)n]2−2n mainly in contrast to low content of [Fe(NH3)n]2+. At low ammonia content, Ni in solution exist as [Ni(C2O4)n]2−2n mainly. At high ammonia contents, Ni in solution exists as [Ni(C2O4)n]2−2n and [Ni(NH3)n]2+ under acidic and alkaline conditions, respectively. The precipitation rate of Ni is higher than that of Fe at low pH value, and lower than that of Fe at high pH value.
Key words: Fe-Ni alloy; solution equilibrium; coordination; ammonia; oxide acid; pH value
