The dissolution conditions of spent Ni-MH batteries anode material with citric acid were studied. The concentration of citric acid, liquid-solid mass ratio, reaction time and reaction temperature were optimized with orthogonal and single factor experiments. The results show that the optimized dissolution conditions are as follows: concentration of citric acid of 2 mol/L, liquid-solid mass ratio of 8:1, reaction time of 50 min and reaction temperature of 90 ℃. Nanocrystal Ni-Co ferrites were synthesized by m...