Electrolytic Preparation Of Fine Particles Of Nickel Powder

This thesis carries on the study of preparing fine nickel powder by electrolysis, and the research includes two parts: gaining nickel powder by electrolysis with no membrane; preparing liquid of nickelous chloride and nickel powder by membrane electrolysis.The research has investigated carefully the effects of experiment parameters on electrolysis. The results of studies show: The current efficiency , the energy consumption and the size of nickel powder can be controlled by changing the electrolytic parameters. The current density, Ni2+ concentration , temperature and pH of electrolytic liquid, the distance of electrodes, the ratio of negative electrode area to positive, the time of gaining nickel powder notably influence the electrolysis. With the perpendicularity experiments we know the influence sequence of this seven parameters on electrolysis, and determine the best parameters of, experience: The temperature of electrolytic liquids is 50-55 C; Ni2+ concentration of electrolytic liquid is 5g/L; The current density is 3500A/m2; The rate of negative electrode area to positive is 4:1; The distance of two electrodes is 25mm; pH of electrolytic liquid is 4-5; The interval time of brushing nickel from negative electrode is 120 seconds. With these parameters, the size of acquired nickel powder is about 1.20 m, moreover the current efficiency is more than 77% and the energy consumption is less than 24.47 kWh/kgNi.It is an new kind of method to make nickelous chloride solution and produce nickel powder by membrane electrolysis at the same time. Through the experiences we acquire the suitable design of electrolysis device. According to the results of the tests, we acquires ideal electrolysis conditions which is fit to prepare nickelous chloride liquid: The current density is 400A/m2; The distance of two electrodes is 14mm; The temperature of electrolytic liquid is 55-60 C; The liquid acidity of the negative room is l~1.5mol/L; The Ni2+ concentration of liquid in positive room is about 60g/L; The membrane depends to the negative electrode; PE203 membrane and network negative electrode made of nickel are good. With these parameters, the current efficiency is 99.7%and the energy consumption of positive electrode is 1992 kWh/tNi.Combining with the studies above we also carry out experiments of gaining nickel powder by membrane electrolysis. The results show that at the same current density, the energy consumption of membrane electrolysis is higher, however the powder size of membrane electrolysis is smaller than that of electrolysis without membrane, thus as when current density is 835A/m2 at average, the acquired nickel powder size is 3.4 m similar to the size of nickel powder making by electrolysis without membrane on high current density which is 3500A/m2, ie 3.2 m. So membrane electrolysis can operate under low current density, and its actual energy consumption must be lower than electrolysis without membrane. Except that if we add a process of purifying impurity, the abolished nickel alloy can substitute electrolytic nickel as the positive electrode, it not only reduces the costs of production, but also opens a shortcut of comprehensive utilization of wastes that contain nickel element in it.