The Preparation Of NiFe₂O₄-based Inert Anode Of Aluminum Electrolysis

NiFe₂O₄is a key material in fabricating inertia anode used for aluminumelectrolysis. The material is synthesized by sintering the powder mixture of NiO andFe₂O₃. High energy ball milling is performed on the powders of NiO and Fe₂O₃. Thenthe ball milled powders are further sintered. XRD, SEM, DSC and size measurementare performed to analyze the physical and chemical reaction in the powders in the ballmilling and the following sintering processes. It is discovered that ball milling leads todistortion of lattice both in Fe₂O₃and NiO. Meanwhile, ball milling results in solidsolution of ferrite into the lattice of NiO when we mixed the two powders together inthe ball rubs. The effects of ball milling on the generation rate of NiFe₂O₄in sinteringdepends on the magnitude of strain energy in powders which is deposited duringball-milling and the rate of the release of the energy. The maximum volume fractionof NiFe₂O₄is generated in the sintered powders when the ball milling time is5h.Powders after milling have a certain regularity in its size, and after the analysis andcalculation of particle size of the powder and the pressure during the milling, wefound that the certain machine and milling parameters will produce certain size of thepowders. In this experiment, the maximum size of powder is14.47μm and theminimum size is between1.6¹.8μm.