Study of Lead Leaching from Waste Molten Slag

An experimental study of causes of lead release from molten and water-granulated slag revealed that the lead content in waste affects the lead content in molten slag, its release from the molten slag, and lead concentration in the granulation water. The granulated slag itself and granulation water adhering to the slag are two conceivable causes of lead release. Experiments in a melting furnace in which granulation water contacts exhaust gas showed that lead in exhaust gas released into granulation water increases the lead concentration in the water. The following might improve the quality of granulated slag from melting furnaces of this type : (1) acceleration of lead volatilization ; (2) avoidance of contact between exhaust gas and granulation water ; (3) adjustment of granulation water pH to the neutral range ; (4) control of lead concentration in granulation water ; and (5) removal, through cleaning, of water adhering to the slag.