【作者】 杜杰；

【导师】 魏琦峰；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2007， 硕士

【摘要】 为解决电解锰与电解二氧化锰工业生产中存在的电流效率低、能耗高、污染严重、设备利用率低等不足,应用离子交换膜替代电解锰生产中常用的物理隔膜,进行了离子膜电解同时制备金属锰与二氧化锰的研究。单因素实验结果表明,离子膜阴极电解金属锰电流效率高于工业普通隔膜电解的电流效率,同时能耗降低;降低电流密度及pH值,升高温度有利于降低槽电压;降低电流密度,升高温度及保持pH为7.5,能够降低能耗;在电解液中添加Se及Na2SO3等能够细化锰晶粒,光亮锰层表面,并维持电解液澄清;实验中电解液pH值2h内保持不变。正交实验结果表明各因素对槽电压影响的显著程度依次为:电流密度、温度、锰离子浓度、硫酸铵浓度、pH;各因素对能耗影响的显著程度依次为:硫酸铵浓度、锰离子浓度、电流密度、温度、pH。最佳工艺条件为:锰离子浓度为35g·L^-1,硫酸铵浓度为130g·L^-1,电流密度为400A·m^-2,pH值为7.5,温度为40℃。探索实验表明在低温、pH为3⁴时离子膜电解可以在阳极生成电解二氧化锰。单因素实验结果表明,降低电流密度,增大氢离子浓度,有利于降低槽电压;电流密度为50A·m^-2,pH大于3,硫酸铵浓度低时可以得到较高的电流效率与较低的能耗。正交实验结果表明各因素对槽电压影响的显著程度依次为:电流密度、锰离子浓度、pH与硫酸铵浓度;对能耗影响的显著程度依次为:pH、硫酸铵浓度、电流密度、锰离子浓度。最佳工艺条件为:电流密度为50A·m^-2,pH大于3,锰离子浓度在45⁵5g·L^-1之间。离子膜电解同时制备金属锰与二氧化锰时,阳极电流效率、能耗等受阴极电解参数的影响不大,而阴极电流效率、能耗受阳极电解参数的影响较大。最佳工艺条件为:阳极液锰离子浓度为50g·L^-1,阳极液pH为4,阳极电流密度为40A·m^-2,阴极液锰离子浓度为40g·L^-1,阴极液硫酸铵浓度为100g·L^-1,阴极液pH为7.5,阴极电流密度400A·m^-2。XRD谱图显示电解锰无杂峰,为立方晶型,电解二氧化锰晶型不完整。阳极产物中含二氧化锰大于82mass%,金属锰达到DJMn99.8的质量标准。线性电位扫描极化曲线显示,pH为7.5及加入添加剂会使阴极极化增大,同时抑制氢的析出。与工业化生产相比,离子膜电解同时制备金属锰与二氧化锰能够在阴、阳两极都制备出锰产品,提高了设备利用率,降低了氢气与氧气的析出量。阴、阳极电流效率分别达到97.53%及98.62%,金属锰与二氧化锰的能耗分别为3591kWh·t^-1及2245kWh·t^-1。更多还原

【Abstract】 The electrodeposition of manganese metal and simultaneous production of EMD by ion-exchange membrane electrolysis was carried out by the ion exchange membrane in place of the diaphragm used in the manganese electrolydeposition to solve the problems of low current efficiency, high energy consumption, high pollution and low utilization rate of equipment that exit in the manganese electrodeposition and manganese dioxide production,The current efficiency was found higher in the cathodic manganese electrodeposition of ionic membrane electrolysis than that in ordinary industrial diaphragm electrolysis by single factor experiments, meanwhile energy consumption values decreased. The voltage could be reduced by reducing the current density and pH and raising the temperature. The energy consumption could be reduced by reducing the current density, raising the temperature and keeping pH aroumd 7.5. The additives as Se and Na2SO3 added in the electrolyte could minish the manganese crystal, make the electrolytic manganese bright and keep the electrolyte clean. The pH maintained the same in 2h in the electrolysis. By orthogonal experiments, it was found that the significance of factors affecting the cell voltage was current density, temperature, concentration of manganese ion, concentration of ammonium sulfate, pH respectively. The significance of factors affecting the energy consumption was concentration of ammonium sulfate, concentration of manganese ion, current density, temperature, pH respectively. Optimized process was as follows: manganese ion concentration of 35g·L^-1, ammonium sulfate concentration of 130g·L^-1, current density of 400A·m^-2, pH of 7.5, temperature of 40℃.It was found that manganese dioxide could be produced on the anode at low temperature and the electrolyte’s pH 3⁴ by tests. The results of single factor experiments show as follows: The cell voltage could be reduced by reducing current density and increasing the concentration of hydrogen ions. Higher current efficiency and lower energy consumption could be attained in the conditions of current density of 50A·m^-2, pH above 3 and low concentration of ammonium sulfate. By orthogonal experiments, it was found that the significance of factors affecting the cell voltage was current density, concentration of manganese ion, pH and concentration of ammonium sulfate respectively. The significance of factors affecting the energy consumption was pH, concentration of ammonium sulfate, current density and concentration of manganese ion recpectively. Optimized process was as follows: current density of 50A·m^-2, pH above 3, manganese ion concentration of 45⁵5g·L^-1.In the electrodeposition of manganese metal and simultaneous production of EMD by ion-exchange membrane electrolysis, the results showed that the anodic current efficiency and energy consumption were affected a little by the cathode factors, but the cathodic current efficiency and energy consumption were affected more by the anode factors. Optimized process was as follows: anodic manganese ion concentration of 50g·L^-1, anodic pH of 4, anodic current density of 40A·m^-2, cathodic manganese ion concentration of 40g·L^-1, cathodic ammonium sulfate concentration of 100g·L^-1, cathodic pH of 7.5, cathodic current density of 400A·m^-2.XRD patterns showed that the purity of electrolytic manganese with cubic crystal was high without miscellaneous peaks, and the crystal of electrolytic manganese dioxide is incomplete. The manganese dioxide in the anode products is greater than 82mass%. It indicated that pH of 7.5 and the addition of additives could make the cathodic polarization increase and the hydrogen reduction inhibited from the linear potential sweep.Compared with the industry product, manganese products can be produced on both anode and cathode by the method of electrodeposition of manganese metal and simultaneous production of EMD by ion-exchange membrane electrolysis in the advantage of higher utilization rate of equipment and lower evolution of hydrogen and oxygen. The cathodic and anodic current efficiencies are 97.53% and 98.62% respectively. The energy consumption of manganese and manganese dioxide are 3591kWh·t^-1 and 2245kWh·t^-1.更多还原