PREPARING MNCO3 FROM RICH-MANGANESE SLAGS

Lixiviated rich-manganese slags Using sulfate acid(98%),under the conditions∶sulfate acid(ml): rich-manganese slags(g)=0.57∶1,no heat,strong stired,reacted for 3 hours,dissolved out Mn,Fe,Ca,Mg,etc.and 97.85% of manganese was transferred to solution.Using H₂O₂ as oxidization reagent to oxidize Fe²⁺ to Fe³⁺,Using NH₃·H₂O and BaS to deposit Fe³⁺,Ca²⁺,Mg²⁺ and other heavy metal ion.So got pure MnSO₄ solution.Adjusted the concentration of MnSO₄ solution and the temperature of the solution,Adjusted pH using NH₃·H₂O,Added(NH₄)₂CO₃ solution to MnSO₄ solution stirred slowly,then,got MnCO₃ sedimentation.After filtration,dryed at 70～80℃,then got the product MnCO₃.By means of orthogonal experiments,got optimal carbonization conditions:(NH₄)₂CO₃(mol)∶MnSO₄(mol)= 1.5∶1,the concentration of(NH₄)₂CO₃ solution and MnSO₄ solution are 2 mol/L and 0.4 mol/L,the pH is 5.5,the temperature of carbonization is 75℃.The MnCO₃ prepared accords with GB10503-89.