How to extract graphite by alkaline acid method

For some graphite with high silicon content, the alkali fusion method to purify the graphite can also realize the comprehensive recovery and utilization of silicon. The solution after alkali fusion acid leaching is acidic, and the silicon impurities in the solution are converted into silicic acid. The silicic acid can be extracted by adding a certain amount of alum, and then calcined at a high temperature of 900° C. to obtain pure silica.

The alkali-acid method is the most widely used method in the industrial production of graphite purification in my country. It has the characteristics of less one-time investment, higher product quality, and strong adaptability, as well as the advantages of simple equipment and strong versatility. The disadvantage is the need for high-temperature calcination, high energy consumption, long process flow, serious equipment corrosion, large loss of graphite, and serious wastewater pollution. Therefore, it is very important to use graphite purification wastewater to prepare polychlorinated aluminum ferric silicate and other comprehensive utilization technologies.