Research of the Formation Cobalt (II) Hydroxide

To determine the conditions for the maximum degree of precipitation, thermodynamic diagrams of the solubility of cobalt(II) hydroxides were calculated. Experimental studies of the precipitation of cobalt (II) hydroxide were carried out by the methods of finite concentrations, potentiometric titration, measurement of the apparent volume of the precipitate and electrical conductivity. The residual concentrations of Co(II) in model solutions were determined, the composition of the precipitates was determined, and the existence of cobalt hydroxocomplexes in solution was substantiated depending on the pH of the solution. The results of thermodynamic calculation showed that the pH of cobalt(II) hydroxide precipitation is 9.5. Methods of potentiometric titration, cyclic voltammetry showed that the formation of hydroxides is a stepwise process. At the initial stage, aqua ions are formed, then the main salt, the composition of which depends on the initial concentration of the solution, and then polyhydroxocomplexes.