首页|Cu2+?Ni2+?NH3?NH4+?C2O42??H2O体系金属离子沉淀行为热力学分析

Cu2+?Ni2+?NH3?NH4+?C2O42??H2O体系金属离子沉淀行为热力学分析

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针对反应体系Cu2+−Ni2+−NH3−NH4+−C2O42−−H2O中Cu2+和Ni2+的反应行为,根据物质守恒原理,建立热力学数学模型.模拟计算结果表明,该体系中金属离子的沉淀是一个复杂的动态平衡过程;在高pH条件下,Cu2+和Ni2+与NH3配合分别形成[Cu(NH3)n]2+(n=3−5)和[Ni(NH3)m]2+(m=3−6)的反应占主导地位.当[C2O42−]T=0.6 mol/L时,Cu2+和Ni2+的共沉淀pH范围在[NH3]T为0.6 mol/L和4.2 mol/L时分别为2.0−6.5和2.0−5.5.在pH>7.0的纯水体系中,由于Cu2+和Ni2+的分步沉淀,Cu−Ni草酸复盐热分解后得到的产物为Cu−Ni复合物.改变沉淀介质为混合溶剂(水/乙醇)可最终制备具有高纯度和良好结晶度的棒状Cu−Ni合金粉末.
Thermodynamic simulation of metal behaviors in Cu2+−Ni2+−NH3−NH4+−C2O42−−H2O system
To investigate the behaviors of Cu2+ and Ni2+ with the change of conditions in Cu2+−Ni2+−NH3−NH4+−C2O42−−H2O reaction system, mathematical models of thermodynamics based on the principle of mass conservation were established. The simulation results indicate that the precipitation of metal ions from the aqueous phase is a complicated dynamic equilibrium process, during which the coordination reactions of Cu2+and Ni2+with NH3 forming [Cu(NH3)n]2+ (n=3−5) and [Ni(NH3)m]2+ (m=3−6) are predominant under high pH conditions, respectively. The pH ranges for the simultaneous precipitation of Cu2+ and Ni2+ are 2.0−6.5 and 2.0−5.5 when [NH3]T equals 0.6 and 4.2 mol/L, respectively, with the prefixed [C2O42−]T of 0.6 mol/L. Due to the fractional precipitation of Cu2+and Ni2+, Cu−Ni composite is obtained after the thermal decomposition of Cu−Ni oxalate complex salts prepared in a pure water system when pH>7.0. By applying the mixed solvent (water/ethanol) as the precipitation medium, the Cu−Ni alloy rods can be finally fabricated with high purity and crystallinity.

coordination−precipitation equilibriumthermodynamic mathematical modelsCu−Ni oxalate complex saltsCu−Ni alloy

苗泽林、湛菁、徐子伟

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中南大学 冶金与环境学院,长沙 410083

中南大学 难冶有色金属资源高效利用国家工程实验室,长沙 410083

配位−沉淀平衡 热力学数学模型 Cu−Ni草酸复盐 Cu−Ni合金

Natural Science Foundation of Hunan Province,ChinaScience and Technology Department of Hunan Province Tackling Key Scientific and Technological Problems and Transformation of MajHunan Key Laboratory for Rare Earth Functional Materials,China

2020JJ47352018GK40012017TP1031

2021

10.1016/S1003-6326(21)65591-7

中国有色金属学报(英文版)
中国有色金属学会

中国有色金属学报(英文版)

CSTPCDCSCDSCI
影响因子：1.183
ISSN：1003-6326
年,卷(期)：2021.31(5)
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