UTILIZATION OF WASTE ALKALINE SOLUTIONS FOR PROCESSING THE ELECTRODE MASS OF NICKEL-CADMIUM BATTERIES

Abstract

The possibility of electrochemical purification of the filtrate after the stage of cadmium precipitation in the technology of processing nickel-cadmium battery masses using sulfamic acid in the galvanostatic mode is considered. The optimal conditions for carrying out the process of purification from nickel and cadmium, such as current density and time, are determined. It is shown that an increase in current density over 0.7 A/cm2 has practically no effect on the degree of extraction of cadmium and nickel, which is 98.8-99.3% and 97.6-97.8%, respectively. It was found that intensive mixing of the electrolyte during electrolysis has a positive effect on the degree of extraction of cadmium and nickel, however, it does not allow reaching the residual concentrations of these metals below the level of their maximum allowable concentrations in the waters of water bodies of fishery importance. It has been established that in order to reduce the metal content below the maximum permissible concentrations, it is necessary to carry out the electrolysis process with a titanium cathode for 14 h. The use of graphite materials with a developed surface or three-dimensional electrodes, such as graphite felt "GFA - 10" and carbon cloth brand "THP - 50R", reduces the time of cleaning from nickel and cadmium by 2 times to concentrations, with a residual content of cadmium and nickel in solution after electrolysis below the MPC level of 0.003 mg/l and 0.008-0.009 mg/l, respectively. The resulting cathodic and anode deposits were characterized by X-ray phase analysis. Cathodic deposits are a mechanical mixture of individual metals cadmium and nickel. Anode deposits are represented by NiO and Ni(OH)2 phases. According to the results of chemical analysis, the cathode product contains 91.5 - 95.8% cadmium and 4.2 - 8.5% nickel. For citation: Chernyshova O.V., Tsygankova M.V., Uvarov B.V. Utilization of waste alkaline solutions for processing the electrode mass of nickel-cadmium batteries. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 2. P. 78-84. DOI: 10.6060/ivkkt.20236602.6701.