CaCl2-Cu2S-NiS熔盐电解生产Cu−Ni合金

摘要

介绍一种金属/合金的生产方法,用于恒电流和恒电位条件下由混合硫化物(Cu2S,NiS)生产Cu?Ni合金,称为直接电化学还原(DER).研究槽电压和槽电流等工艺参数对还原得到的化合物组成的影响,以生产工业所需的CuNi10,CuNi20和CuNi30等合金.在1200℃下采用循环伏安法(CV)考察Cu2S和NiS在CaCl2熔体中的电化学行为.根据CV研究结果,Cu2S的阴极还原是一步完成的,即Cu2S?Cu;NiS的阴极还原则分两步进行,即NiS?Ni3S2?Ni.恒电流研究表明,在10 A电流下电解15 min,可制备出最高硫含量为320×10?6的高纯CuNi10合金.扫描电子显微镜以及能量色散X射线能谱和光学发射光谱(OES)测试结果表明,在2.5 V电压下直接电化学还原15 min,可制备出杂质含量低(即硫含量小于60×10?6)的所选成分的Cu?Ni合金.%An alternative metal/alloy production method, known as direct electrochemical reduction (DER), was introduced for the fabrication of CuNi alloys from mixed sulfides (Cu2S, NiS) under both galvanostatic and potentiostatic conditions. The influences of the process parameters (e.g., cell voltage and current) on the compositions of the reduced compounds were investigated to yield industrially desirable alloys, namely, CuNi10, CuNi20, and CuNi30. The electrochemical behaviors of Cu2S and NiS in CaCl2 melt were examined at a temperature of 1200 ℃ via cyclic voltammetry (CV). Based on the CV results, the cathodic reduction of Cu2S occurred in one step and cathodic reductions of NiS occurred in two steps, i.e., Cu2S?Cu for copper reduction and NiS?Ni3S2 ?Ni for nickel reduction. Galvanostatic studies revealed that it was possible to fabricate high-purity CuNi10 alloys containing a maximum sulfur content of 320×10?6 via electrolysis at 10 A for 15 min. Scanning electron microscopy along with energy-dispersive X-ray spectrometry and optical emission spectroscopy (OES) examinations showed that it was possible to fabricate CuNi alloys of preferred compositions and with low levels of impurities, i.e., less than 60×10?6 sulfur, via DER at 2.5 V for 15 min.