RESEARCH ON THE EXTRACTION OF ALUMINA FROM KAOLIN IN PHU THO BY HYDROCHLORIC ACID
Abstract
Kaolin is a natural mineral that contains high amounts of aluminum oxide and it is used to produce aluminum salts. It is easy to metabolisms aluminum oxide in kaolin to aluminum salts by using acids. With hydrochloric acid, aluminum chloride salts are obtained to produce poly aluminum chloride alum which has more advantageous than sulfate alum. But Hydrochloric acid is volatile acid, especially when reaction is proceeded at high temperature, high acid concentration and acid is residual, so there has more evaporated acids, the aluminum separation efficiency decrease. In order to solve this problem, the research used cold sodium chloride solution to condense acid vapor to return reactor. The results showed that aluminum separation efficiency is high when using hydrochloric acid. Specifically: heating kaolin at 600oC for 2 hours; masticating into size 0,1 mm, mixing with hydrochloric acid 25% at 100°C for 2 hours, aluminum separation efficiency is 82,36%.
