Provided are: a MnZn-based ferrite which allows to have a low magnetic core loss and to suppress a time-dependent change of magnetic property under a high-temperature environment by a control of ambient oxygen concentration and an increase of the magnetic core loss, and a method for manufacturing the same. The MnZn-based ferrite is characterized in that Fe ranges from 53.25 mol % or more to 54.00 mol % or less on the basis of Fe.sub.2O.sub.3, Zn ranges from 2.50 mol % or more to 8.50 mol % or less on the basis of ZnO and Mn is the remainder on the basis of MnO, Si ranges from more than 0.001 mass % to less than 0.02 mass % on the basis of SiO.sub.2, Ca ranges from more than 0.04 mass % to less than 0.4 mass % on the basis of CaCO.sub.3, Co is less than 0.5 mass % on the basis of Co.sub.3O.sub.4, Bi is less than 0.05 mass % on the basis of Bi.sub.2O.sub.3, Ta is less than 0.05 mass % on the basis of Ta.sub.2O.sub.5, Nb is less than 0.05 mass % on the basis of Nb.sub.2O.sub.5, Ti is less than 0.3 mass % on the basis of TiO.sub.2, and Sn is less than 0.3 mass % on the basis of SnO.sub.2, and note that the converted total amount of Ta.sub.2O.sub.5 and Nb.sub.2O.sub.5 is less than 0.05 mass % and the converted total amount of TiO.sub.2 and SnO.sub.2 is less than 0.3 mass %.

Provided are: a MnZn-based ferrite which allows to have a low magnetic core loss and to suppress a time-dependent change of magnetic property under a high-temperature environment by a control of ambient oxygen concentration and an increase of the magnetic core loss, and a method for manufacturing the same. The MnZn-based ferrite is characterized in that Fe ranges from 53.25 mol % or more to 54.00 mol % or less on the basis of Fe.sub.2O.sub.3, Zn ranges from 2.50 mol % or more to 8.50 mol % or less on the basis of ZnO and Mn is the remainder on the basis of MnO, Si ranges from more than 0.001 mass % to less than 0.02 mass % on the basis of SiO.sub.2, Ca ranges from more than 0.04 mass % to less than 0.4 mass % on the basis of CaCO.sub.3, Co is less than 0.5 mass % on the basis of Co.sub.3O.sub.4, Bi is less than 0.05 mass % on the basis of Bi.sub.2O.sub.3, Ta is less than 0.05 mass % on the basis of Ta.sub.2O.sub.5, Nb is less than 0.05 mass % on the basis of Nb.sub.2O.sub.5, Ti is less than 0.3 mass % on the basis of TiO.sub.2, and Sn is less than 0.3 mass % on the basis of SnO.sub.2, and note that the converted total amount of Ta.sub.2O.sub.5 and Nb.sub.2O.sub.5 is less than 0.05 mass % and the converted total amount of TiO.sub.2 and SnO.sub.2 is less than 0.3 mass %.

Manganese oxide nanoparticles having a chemical composition that includes Mn.sub.3O.sub.4, a sponge like morphology and a particle size from about 65 to about 95 nanometers may be formed by calcining a manganese hydroxide material at a temperature from about 200 to about 400 degrees centigrade for a time period from about 1 to about 20 hours in an oxygen containing environment. The particular manganese oxide nanoparticles with the foregoing physical features may be used within a battery component, and in particular an anode within a lithium battery to provide enhanced performance.

Manganese oxide nanoparticles having a chemical composition that includes Mn.sub.3O.sub.4, a sponge like morphology and a particle size from about 65 to about 95 nanometers may be formed by calcining a manganese hydroxide material at a temperature from about 200 to about 400 degrees centigrade for a time period from about 1 to about 20 hours in an oxygen containing environment. The particular manganese oxide nanoparticles with the foregoing physical features may be used within a battery component, and in particular an anode within a lithium battery to provide enhanced performance.

To provide electrolytic manganese dioxide excellent in cell performance in high rate discharge and middle rate discharge when used as a cathode material for alkaline manganese dry cells, and a method for its production. Electrolytic manganese dioxide, characterized in that the average size of mesopores is at least 6.5 nm and at most 10 nm, and the alkali potential is at least 290 mV and at most 350 mV; a method for its production and its application.

To provide electrolytic manganese dioxide excellent in cell performance in high rate discharge and middle rate discharge when used as a cathode material for alkaline manganese dry cells, and a method for its production. Electrolytic manganese dioxide, characterized in that the average size of mesopores is at least 6.5 nm and at most 10 nm, and the alkali potential is at least 290 mV and at most 350 mV; a method for its production and its application.

A variety of systems, methods and compositions are disclosed, including, in one method for recycling a spent alkaline battery comprising: dissolving insoluble metal ions in aqueous solution thereby producing pregnant leach solution; extracting zinc sulfate from aqueous solution thereby producing zinc sulfate product and raffinate solution comprising manganese sulfate and potassium sulfate; separating manganese hydroxide from raffinate solution thereby producing manganese sulfate product and aqueous potassium sulfate solution; crystallizing aqueous potassium sulfate solution to produce solid potassium sulfate product. A system for recycling spent alkaline battery comprising: first liquid-solid extraction unit capable of dissolving insoluble metal ions in aqueous solution thereby producing pregnant leach solution; liquid-liquid extraction unit capable of extracting zinc from pregnant leach solution; second liquid-solid extraction unit capable of precipitating manganese hydroxide from raffinate produced by liquid-liquid extraction unit; and third liquid-solid extraction unit capable of crystallizing aqueous potassium sulfate solution produced by second liquid-solid extraction unit.

A variety of systems, methods and compositions are disclosed, including, in one method for recycling a spent alkaline battery comprising: dissolving insoluble metal ions in aqueous solution thereby producing pregnant leach solution; extracting zinc sulfate from aqueous solution thereby producing zinc sulfate product and raffinate solution comprising manganese sulfate and potassium sulfate; separating manganese hydroxide from raffinate solution thereby producing manganese sulfate product and aqueous potassium sulfate solution; crystallizing aqueous potassium sulfate solution to produce solid potassium sulfate product. A system for recycling spent alkaline battery comprising: first liquid-solid extraction unit capable of dissolving insoluble metal ions in aqueous solution thereby producing pregnant leach solution; liquid-liquid extraction unit capable of extracting zinc from pregnant leach solution; second liquid-solid extraction unit capable of precipitating manganese hydroxide from raffinate produced by liquid-liquid extraction unit; and third liquid-solid extraction unit capable of crystallizing aqueous potassium sulfate solution produced by second liquid-solid extraction unit.

A positive electrode for a sodium ion secondary battery includes a positive electrode active material that intercalates and deintercalates sodium ions, a conductive assistant, a binder, and a carboxylic acid, the binder containing a vinylidene fluoride-based polymer, the carboxylic acid having at least one of a boiling point and a thermal decomposition point, and whichever of the boiling point and the thermal decomposition point is lower being higher than 150° C. The carboxylic acid is preferably at least one selected from the group consisting of hydroxy acids and polycarboxylic acids.

Methods for producing ethylene using nanowires as heterogeneous catalysts are provided. The method includes, for example, an oxidative coupling of methane catalyzed by nanowires to provide ethylene.