SYNTHESIZING Mn-Zn FERRITE FROM SPENT ZINC- CARBON BATTERIES THROUGH HYDROMETALLURGICAL PROCESSES

摘要

The synthesis of Mn-Zn ferrite powder from spent zinc-carbon batteries was investigated using a series of physical treatment, sulfuric acid leaching and co-precipitation. Physical separation methods such as crushing, magnetic separation and sieving were applied to generate a non-magnetic material of 8-mesh undersize for subsequent leaching process. The 8-mesh undersize of the spent zinc-carbon batteries was assayed 23.9% Mn, 14.9% Zn, and 4% Fe. Metal extractions obtained in sulfuric acid leaching at the solid/liquid ratio of1:10, 2 M H_2SO_4, and 60°C with 6 vol.% H_2O_2 addition were 97.9% Mn,98.0% Zn and 55.2% Fe. The leach liquor was finally adjusted to the Mn:Zn:Fe mole ratio of 1:1:4 suitable for producing MnZnFe_4O_8 ferrite powder by the addition of Mn, Zn and Fe sulfates followed by pH control. A co-precipitationtest for Mn-Zn ferrite powder was performed at 80°C, O_2 gas flowing at 1.3 L/min. As a result of co-precipitation, Mn-Zn ferrite nanoparticles in 20 nm size with spinel structure were successfully synthesized. The saturation magnetizations of Mn-Zn ferrite powder (Mn_(1-x)-Zn_xFe_2O_4) were determined to be 39-91 emu/g with various zinc contents (X=0.2-0.8).