Les Nitrates Basiques Mixtes et Hydroxydes Mixtes de Nickel et de Cobalt

Abstract

AbstractThe basic nickel and cobalt nitrates, obtained by addition of soda to Ni(NO3)2 or Co(NO3)2 solutions (O, 2 M Me++/1), have respectively the compositions 4 Ni(OH)2.Ni(OH)0, 75(NO3)1, 25 (I) and 4 Co(OH)2.Co1, 25(OH)1.0(NO3)1, 5 (II. They are unstable and tend to transform into hydroxydes by aging or increase of temperature.In solutions of Ni++ + Co++, at 20°C, precipitation of mixed basic nitrates occurs first and the distribution curve (Ni++/Co prec. as a function of Ni++/Co++ final sol.) shows a change of slope at the transition from basic salt II into I. By prolonging the reaction time, the mixed basic nitrates with predominant presence of cobalt transform into Co1‐xNix (OH)2 while in the nickelrich range, the mixed basic nitrate 5 Ni1‐yCoy(OH)8, 75(BO3)1, 25 (1) is maintened because of the Ni/Co substitution process. A demixing zone separates these two solid solutions.At 75°C, simply the mixed hydroxydes of nickel and cobalt are formed.