Preparation of nickel-manganese composite oxide by room temperature solid state reaction-calcining decomposition

Using NiCl2.6H2O and MnCl2.4H2O as major reactants,nickel-manganese composites were synthesized by the solid state reaction at room temperatures with three difference reactants((NH4)2C2O4.H2O,NaOH,NaCO3.10H2O).The nickel-manganese oxides were synthesized by calcining three precursors at 400,300,500 ℃ for 3 h.-r G mΘ and -r H mΘ for three solid state reactions at room-temperature were estimated by the thermodynamic data.The effects of difference reaction on the oxides were studied.The processes,particle size and crystallography characters were studied by means of DSC-TGA,XRD and TEM.The results show that spinel NiMn2O4 and MnNi2O4 are obtained by decomposing nickel-manganese oxalic acid;Ilmenite-type MnNiO3 is obtained by decomposing nickel-manganese hydroxide;Ilmenite-type MnNiO3,spinel NiMn2O4 and MnNi2O4 are obtained by decomposing nickel-manganese carbonate.The particle size of nickel-manganese oxide products increases by turn of nickel-manganese hydroxide,oxalic acid,carbonate.