Influence of non-stationary electric current on dissolution оf metals in aqueous solutions of alkali

Abstract

Non-stationary effects can be widely used as an intensifying factor in technological processes and as a tool for studying chemical systems. Studies of energy effects on structural transformations in liquid systems can make it possible to significantly intensify many chemical and metallurgical processes. We have studied the solubility of aluminum, iron and molybdenum in alkaline solutions under the influence of alternating electric current. A two-electrode cell was used. The electrodes were made from dissolved metal. The frequency of the electric current varied from 20 to 200,000 Hz. In the process of dissolving aluminum in an alkaline solution at the same current frequency and alkali concentration, the mass loss of the aluminum sample increases with increasing current strength up to 0.042-0.044 g. A further increase of current practically blocks the dissolution of aluminum - the change in mass was 0.005-0.007 g of Al. Increasing the alkali concentration to 5.7% KOH significantly reduces the dissolution of aluminum, the weight loss is 0.009 g. The entire surface of the electrodes is covered with a film after 6 hours of dissolution. An analysis of the phases on the aluminum surface showed that the film is a phase based on potassium. The thickness of the potassium film varies depending on the depth of immersion of the electrodes in the solution and on the time of the experiment. The structure and composition of potassium and aluminum compounds could not be established.