炭醸ガス加圧下におけるＣｏ（ＮＯ３）２‐ＮａＯＨ‐ＣＯ２水溶液からのコバルト炭酸塩の生成

Abstract

Precipitation of cobalt carbonate from Co (NO3) 2-NaOH aqueous solution under high pressure carbonic acid (CO2) gas was investigated experimentally using a glass autoclave. The results obtained in this experiment are as follows:1) In Co (NO3) 2-NaOH aqueous solution under argon gas atmosphere, amount of precipitation increases while the pH of the solution remains nearly constant at 7.2-7.9 asNaOH concentration increases. However, the pH increases rapidly with NaOH concentration inthe region where the formation of precipitation ceases. 2) In Co (NO3) 2-NaOH-CO2 aqueous solution, application of CO2 gas makes precipitation absent in case of small precipitation amount and present in case of large precipitation amount in the initial Co (NO3) 2-NaOH aqueous solution. The pH ofthe solution is nearly constant at 6.0-6.5 in the region of higher NaOH concentration. 3) It was suggested that the precipitation formed in Co (NO3) 2-NaOH aqueous solution would be Cobalt Hydroxide, while the precipitation formed in Co (NO3) 2-NaOH-CO2 aqueous solution, would be Cobalt Carbonate or Basic Cobalt Carbonate.