Study of the kinetics of cadmium cementation in the presence of flocculants based on polyacrylamide

Abstract

The reduction of cadmium ions from aqueous solutions was carried out with zinc powder, particle size from 63 to 200 μm. In a number of experiments, the effect of flocculants based on polyacrylamide on the process of cadmium cementation was tested. The process was carried out in the temperature range from 30 to 50 °C with continuous stirring at a speed of 200 rpm with an overhead stirrer. Kinetic curves were plotted using a cadmium selective electrode. It has been shown that increasing the reaction temperature has a positive effect on cementation. The effect of the concentration of flocculants on the duration of the initial section of the kinetic curves was studied; the additives have the greatest effect at a concentration of 0.07 g/l. The introduction of a flocculant into the electrolyte in an amount of 0.07 g/l reduced the degree of cadmium cementation. The data obtained made it possible to calculate the apparent activation energies and the reaction mode coefficient. The addition of a flocculant affects the morphology of the reaction products and the consumption of zinc powder.