Method for extracting manganese dioxide from waste alkaline zinc-manganese dry battery and recycling manganese dioxide in lithium manganate secondary battery

The invention discloses a preparation method for extracting manganese dioxide from a waste alkaline zinc-manganese dry battery and preparing a lithium manganate secondary battery by using the manganese dioxide. According to the method, a carbon bag of an alkaline zinc-manganese battery is collected, a wet recovery technology combining impurity removal, reduction, precipitation and a calcination method is adopted to prepare epsilon-MnO2, the epsilon-MnO2 reacts with lithium hydroxide by utilizing a high-temperature solid-phase method to prepare a final product, namely high-purity lithium manganate, and the high-purity lithium manganate can be used as a high-performance lithium ion battery positive electrode material. The method has the advantages that experimental conditions in the process are easy to control, raw materials are low in price and wide in source, required reagents and instruments are common and low in price, and the method has extremely high feasibility in both technology and economy. The prepare