Oxidation-Precipitation of Cobalt (II) in Aqueous Sulphate Solution Using Sodium Persulfate

摘要

Oxidation and precipitation of Co(II) in sulphate solution using Na_2S_2O_8 as an oxidant was studied. The main factors affecting the oxidation of Co(II), the reaction time, temperature, pH of solution, agitation speed and amount of added Na_2S_2O_8, were investigated. The results indicated that the oxidation rate of Co(II) was not affected by the agitation speed and the amount of the oxidant, but it increased obviously with an increasing pH of the solution and reaction temperature. The kinetics equation was established as -ln(l-X) = k_1 ·[H~+]~(-0.4755)·exp (3800/T)·t with a first order reaction. The product precipitated by the oxidation of Co(II) was CoOOH, and Co_2O_3 was obtained by calcination of CoOOH at 300 °C for 2 hours. The particle size of the precipitated product was influenced by the pH of the solution.