Studies on Coprecipitation of Metal Ions withAluminum Hydroxide. IV. Cobalt (II)

Coprecipitation of cobalt (II) ions with aluminun hydroxide was investigated, using ammonium hydroxide or sodium hydroxide as precipitant. In this study, precipitate of aluminum hydroxide was usually prepared directly in the solution containing cobalt salt, but in some case, it was pre-formed and cobalt salt solution was added to it later on. The relation between percentage of cobalt coprecipitated and pH value of the solution was investigated in detail. Effects of concentrations of aluminum salt, cobalt salt, and ammonium salt were also examined. The amounts of cobalt in precipitate or filtrate were determined polarographically