INTERFACE REACTION AFFECTS FE~(3+) MOBILITY IN JAROSITE AND ALKALINE COAL FLY ASH

摘要

To investigate the effects of interface precipitation on the mobility of constituents in layered acidic jarosite and alkaline fly ash systems, small diffusion tube (? 8 mm, L50mm) experiments have been carried out using ~(59)Fe~(3+) as a radiotracer. Our principal result indicates that ~(59)Fe~(3+) accumulates at the interface of jarosite and fly ash due to the coupling of diffusion and precipitation. Diffusion of ~(59)Fe~(3+) is caused by the concentration gradient between jarosite and alkaline fly ash, whereas precipitation of ferric hydroxide is due to the exceedingly low solubility of Fe~(3+) at the interface where the pH changes markedly. Based on our ~(59)Fe~(3+) results the behavior of aluminium, zinc, and lead in jarosite and alkaline fly ash can be predicted.