Method for preparing aluminum cesium sulfate and aluminum rubidium sulfate by using tantalum-niobium tailings lepidolite

The invention provides a method for preparing aluminum cesium sulfate and aluminum rubidium sulfate by using tantalum-niobium tailings lepidolite, which is characterized by comprising the steps of: smashing lepidolite powder into about 100 to 200 meshes; putting the lepidolite powder and a sulfuric acid solution with a concentration of 30 to 70 percent according to a solid-liquid mass ratio of 1:(2-8) into a reaction device; reacting for 3 to 10 hours at 60 to 200 DEG C to remove fluorine and obtain a sulfuric acid solution containing Li , separating and removing a fluorine containing solution; filtering and separating the sulfuric acid solution containing Li , washing filter residue with water fully to remove the filter residue and obtain filtrate which is mother solution 1; and changing the temperature of the mother solution 1 to 10 to 100 DEG C under stirring in order to separate solid aluminum cesium sulfate and solid aluminum rubidium sulfate.