Scrubbing Hazardous Wastes of the Spanish Phosphate Industry and Used Tires Ash via Coal Fly Ash and Incorporation of the Product in Concrete for Civil Engineering Purposes

摘要

Coal fly ash(FA)is an abundant commodity in countries using steam coal for power production.This results in the production of large amount of FA,from which less than 50% of it is being used.As this FA is considered as Class F FA(<20% CaO)it may act as an excellent scrubber and fixation reagent for acidic wastes containing many toxic trace elements.This paper studies the potential use of FA,categorized as Class F,as a neutralization and fixation reagent for both the hazardous sludge waste of the phosphate industry and the used tires ash formed during the fire in Sese?a(near Toledo,May 13th,2016)of 5M tires.Several analytical techniques(ICP,SEM,XRD,leaching experiments – EN12457-2)were used to this end.These results allowed identifying the best ratios between FA/waste in order to reach full neutralization and fixation.As investigated in previous studies,addition of Caspecies source prevents excessive leaching of As,Mo,and Se,and allows achieving full neutralization and fixation.The final aggregate product compound was used as a partial substitute in concrete that can be used in civil engineering projects,as an environmental safe product.