PREPARATION METHOD OF EXPANDED GRAPHITE

摘要

PURPOSE: A preparation method of expanded graphite is provided which reduces the amount of acid used to the minimum by preparing graphite oxides using liquid fuming sulfuric acid as an oxidizer, and prevents environmental pollution by injecting the oxidizer used into the preparation process of fuming sulfuric acid again. CONSTITUTION: The preparation method of expanded graphite comprises first step of oxidizing graphite using gas phase SO3 gas or liquid phase fuming sulfuric acid produced from the preparation process of fuming sulfuric acid; second step of washing the oxidized graphite with a washing solution; and third step of expanding the graphite by irradiating microwave onto the washed graphite, or heat treating the washed graphite, wherein concentration of the SO3 gas in the first step is 2 to 100%, the washing solution of the second step is selected from water, a caustic soda solution and water glass, the microwave irradiation of the third step is done in the range of 30 to 30000 MHz for 1 minute to one hour, and the heat treatment of the third step is done in the temperature range of 400 to 1200 deg.C for 30 seconds to 30 minutes.