The insulating mortar perlite expanded furnace was successfully invented in Feb 2003 by our president, a superior engineer, Kong Keqiang. In the same year, it obtains the patent in practice and in creativity, and the first furnace was brought into commercial process in the world. 300 sets of them have been continuously used for three years or five years, which are specially used to manufacture closed perlites, surface melt hollow ball perlite . .........................