Synthesis Of NiCo₂O₄ And Study Of The Application On The Electrolysis Of Sodium Aluminate With Oxygen Cycle

Alumina as the basic raw material of aluminum, the production has increased year by year because of the widely used of aluminum. In this paper, based on the low decomposition rate, large seed tank and high-grade bauxite of the traditional Bayer process and high energy consumption of sintering method, developing a new alumina production technology is very important. After investigating the literatures of domestic and overseas and in view of the existing weakness about easy blocking sodium aluminate ion membrane electrolysis and high energy consumption of the preparation process of alumina electrolysis, we put forward a new solution under a certain depth of electrolytic cycle of sodium aluminate, and use the oxygen cycle energy-saving electrolytic method to achieve the high energy efficiency.Meanwhile, the granular aluminum hydroxide are obtained.In order to reduce the polarization during electrolysis anode oxygen evolution process, this paper focuses on the oxygen evolution performance of Ti/NiCo2O4 prepared by the thermal decomposition and Ni/NiCo2O4 prepared by the electrodeposition-thermal oxidation.Firstly, the anode Ti/xRuO2-(1-x)NiCo2O4 was prepared by the thermal decomposition, with the precursor solution consisted of cobalt, nickel and ruthenium metal salt. The structures and morphologies were characterized by means of XRD, SEM. The electrochemical properties of products were investigation through potentiodynamic scanning, constant-current polarization and cyclic voltammetry test. The results show that the best roasting temperature is 400℃ and the polarization potential is 0.68 V, reduced by 26.9%, when the best doping ratio of Ru and Ni is 0.1:0.9. At the same time, the anode Ni/NiCo2O4 was prepared by the electrodeposition- thermal oxidation. The optimal synthetic conditions were obtained and the structures and morphologies were characterized by means of XRD, SEM. The electrochemical properties of products were investigation through potentiodynamic scanning, constant-voltage polarization constant-current polarization and cyclic voltammetry test. The results show that the best current density is about 4 mA cm-2, electrodeposition time is controlled 6 h, thermal oxidation temperature is 400℃. Compared with Ti/NiCo2O4, the polarization potential,0.65 V, is reduced by 30.1% with the same test condition.Finally, we construct a circulation system with the Ti/0.1RuO2-0.9NiCo2O4 and Ni/NiCo2O4 used as anode, the oxygen electrode as cathode. The product alumina hydroxide can be get by electrolyzing aluminum acid sodium solution, combined the technique of membrane electrolytic. The structures and morphologies were characterized by means of XRD, SEM. The results show that the style of alumina hydroxide isy-Al(OH)3, and the maximum current efficiency is 97.1% when the electrolytic temperature is 65℃.