The focus of this study was to design, develop, and assess the potential for combining the industrial co-product materials paper clay and steel slag, in order to provide environmentally sustainable solutions. The primary problem that is addressed by the research is the remediation of heavy-metal-contaminated groundwater. Paper clay generally contains organic fibers and tissues (lignin and pulp), clay fillers, and trace components (resins, starch, etc. added to produce specific paper products). In this study, paper clay was determined to have the potential to adsorb heavy metals, and in compacted form could achieve permeability values within the desired range of 10-5 to 10-7 cm/sec required for reactive barriers. Slump tests showed that paper clay can achieve the required slump of between 5.08 and 15.24 cm (2 and 6 inches), similar to that of a workable soil–bentonite backfill with permeabilities of between 10-5 to 10-6 cm/sec, similar to those of soil–bentonite filter cakes. Steel-making slags are the co-products of the processing of iron and scrap into the desired type and grade of steel in furnaces such as the open-hearth, basic oxygen (BOF) and electric arc (EAF) furnaces. Steel-making slags are composed primarily of calcium silicates and alumino-ferrites, and fused oxides of calcium, iron, magnesium and manganese. The steel slag tested in this study had an acid neutralization potential of approximately 83% as calcium carbonate (CaCO3), and on average showed over 90% removal efficiency for the heavy metals tested.

Key words: heavy metals, paper clay, reactive barriers, slurry walls, steel slag

Land Contamination & Reclamation, 18 (4), 333-343 (2011)