Study On The Preparation Of Mn-Zn Power Ferrite From Zn-Mn Dry Batteries Waste

With the increasing improvement of people’s living standard, Zn-Mn dry batteries have been already widely used as a conventional portable energy. However, because of the low recovery rate of Zn-Mn dry batteries waste in our country, the batteries wastes bring great harm to environment, which pose a potential risk to the human. Therefore, effective utilization of Zn-Mn dry batteries wastes has thus become necessary from the viewpoint of environmental preservation, resource saving and waste volume reduction. Meanwhile, with the rapid development of information industry and the electronics industry, the demand for high-performance Mn-Zn power ferrite materials is increasing gradually. Considering the high grades of zinc and manganese in the Zn-Mn dry batteries waste, the comprehensive utilization of batteries waste including the hydrometallurgical route and ceramic process was used to prepare the corresponding Mn-Zn power ferrite materials. This technology not only reduces the environmental pollution, but also provides an effective way for the development of ferrite materials, which result in huge economic and social benefits. In the study, chemical co-precipitation method was employed to prepare high-quality Mn-Zn powders using Zn-Mn dry batteries waste as starting materials. Then, these powders were used to produce Mn-Zn power loss ferrite through the ceramic processes including ball milling, pre-sintering, secondary ball milling, granulating, forming and sintering. The main research results are as follows:Hydrometallurgical route including acid leaching, two-stage purification, co-precipitation, was used to recycle Zn-Mn dry batteries waste and prepare the Mn-Zn composite powers. The concentration of Si, Ca, Mg, Al in the powders is0.0081wt%,0.0089wt%,0.0075wt%0.0008%, respectively which meet the requirements for preparation of Mn-Zn power ferrite. Traditional ceramic process using synthesized powders was conducted to prepare power loss Mn-Zn ferrite product. The factors such as formula, pre-sintering temperature, milling time, doping and sintering conditions have great influence on the microstructure, initial permeability and power loss of Mn-Zn power ferrite. The optimum preparation conditions fare as follows:the formula Fe2O3:MnO:ZnO=53.797:35.023:11.180(mole fraction); pre-sintering temperature950℃; milling time10.0h. additives combination0.02wt%CaCO3+0.02wt%ZrO2+0.01wt%V2O5+0.02wt%Nb2O5; sintering temperature1320℃; sintering atmosphere5.0%partial pressure of oxygen.Mn-Zn power ferrite products are prepared through the optimal formula, pre-sintering temperature, milling time, additive combination and the sintering process parameters determined based on the experiments, The comprehensive performances of Mn-Zn power loss ferrite in this study are as follows:initial permeability2162(25℃,10kHz,50mV); saturation magnetic flux density BS5O5mT (25℃,1194A·m-1) and402mT (100℃,1194A·m-1); Curie temperature Tc223℃and power loss per unit volume PCV446kW·m-3(100kHz,200mT,100℃) indicating that the material have been close to the PC40product made in TDK corporation of Japan.