PRETREATMENT METHOD FOR RECOVERING RARE EARTH ELEMENT FROM DISPOSED FLUORESCENT LAMP AND METHOD OF RECOVERING RARE EARTH ELEMENT USING SOLID MATTER OBTAINED BY THE PRETREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a pretreatment method of efficiently recovering a rare earth element with the help of a fluorescent substance released from a disposed fluorescent lamp with an inclusion of a white fluorescent lamp and 3-wavelength fluorescent lamp, and also, of preventing health hazard and environmental contamination due to mercury from occurring, as well as a method of recovering a rare earth element contained in solid matter obtained by the pretreatment method.;SOLUTION: First, the mercury is removed by heating a fluorescent substance released from a disposed fluorescent lamp under vacuum, prior to recovering the rare earth element from the fluorescent substance on the glass tube inner surface of the disposed fluorescent lamp. Next, the fluorescent substance is charged into an acid solution which can dissolve Ca and the acid solution is stirred, then the stirring operation is stopped. Further, the solid matter precipitating inside the acid solution is separated, and then is cleaned and dried. After that, the solid matter obtained by the pretreatment method is ground, then the obtained grinds are charged into a low-density acid solution. Thus, the rare earth element is made to leach and recovered from the acid solution.;COPYRIGHT: (C)2010,JPO&INPIT