SERIAL BATCH TESTS PERFORMED ON MUNICIPAL SOLID-WASTE INCINERATION BOTTOM ASH AND ELECTRIC-ARC FURNACE SLAG, IN COMBINATION WITH COMPUTER MODELING

To predict long-term behaviour of wastes, knowledge is needed about th e mechanisms controlling the leaching. The serial batch leaching test, developed in this study, is a version of an ordinary column test that allows sampling at different places in the column. In this study the results from the experiment are compared with computer simulations mad e with the coupled geochemical and transport program CHEMFRONTS. The e xperiments showed that some elements, for example potassium, are easil y leached, while the leaching of others, for example iron, is slower. The leaching of some elements is solubility controlled whereas others are controlled by dissolution kinetics. The comparison between the exp eriments and the computer simulations shows good agreement for most el ements. A flow through system has been simulated for the steel slag ba sed on the results from the experiments and the computer simulation th ereof. The latter simulation gives an idea of the long-term leaching b ehaviour of the steel slag. The conclusion of the work is that a combi nation of serial batch leaching test and computer simulation with a ge ochemical transport give good leaching of waste materials. (C) 1997 IS WA.