Activated magnesium oxide precipitation method for the preparation of cobalt is a commonly used method of hydrometallurgy, which has the advantages of simple process, low cost and high product purity. The basic principle of this method is to utilize the adsorption effect of activated magnesium oxide on cobalt ions, and precipitate cobalt ions from the solution.
The specific preparation process steps are as follows:
Raw material preparation.
Active magnesium oxide: should choose the active magnesium oxide with large specific surface area and high adsorption activity.
Cobalt salt solution: commonly used cobalt salts include cobalt sulfate, cobalt chloride, cobalt nitrate and so on. The concentration and pH value of the solution should be adjusted according to the specific situation.
Precipitation reaction.
Add the cobalt salt solution into the container containing activated magnesium oxide and stir the reaction under certain temperature and pH conditions.
The reaction equation is as follows:
MgO + Co2+ + 2OH- → Mg(OH)2↓ + Co(OH)2↓
Solid-liquid separation.
The slurry after the reaction is filtered or settled to obtain crude nickel cobaltate precipitate.
The crude nickel cobaltate precipitate should be washed in time to remove impurities.
Roasting.
Roast the washed crude nickel cobaltate precipitate in air or inert atmosphere to get the finished cobalt oxide product.
The roasting equation is as follows:
Co(OH)2 → CoO + H2O
Influence of Process Parameters on Preparation.
Specific surface area of active magnesium oxide: the larger the specific surface area, the higher the adsorption activity and the more cobalt ions are precipitated.
Concentration of cobalt salt solution: the higher the concentration, the more cobalt ions are precipitated, but there is a possibility of secondary dissolution.
pH value of the solution: pH value should be controlled within a certain range to ensure the effective precipitation of cobalt ions.
Reaction Temperature: Higher temperature accelerates the reaction rate, but impurities may be generated.
Precautions: The quality of the activated magnesium oxide should be related to the quality of the cobalt ion.
The quality of active magnesium oxide should be measured and proportional to the cobalt ion content in the cobalt salt solution.
Good agitation should be maintained during the precipitation reaction to prevent agglomeration.
The roasting temperature should not be too high, otherwise the purity of cobalt oxide will be reduced.