Location: Northwest Irrigation and Soils ResearchTitle: Analysis of total metals in waste molding and core sands from ferrous and non-ferrous foundries Author
|Banda Noriega, Roxana|
|Dungan, Robert - Rob|
Submitted to: Journal of Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2012
Publication Date: 11/15/2012
Citation: Miguel, R.E., Ippolito, J.A., Leytem, A.B., Porta, A.A., Banda Noriega, R.B., Dungan, R.S. 2012. Analysis of total metals in waste molding and core sands from ferrous and non-ferrous foundries. Journal of Environmental Management. 110:77-81. Interpretive Summary: Sand is used by foundries to create molds and cores to produce metal castings; however, the sands are eventually discarded. While a large portion of the sands are discarded in landfills, there are efforts around the world to beneficially use the sands in geotechnical and agricultural applications. A major barrier to their beneficial use is concern among regulatory agencies that the sands contain metals at concentrations deemed hazardous. In this study, total metal concentrations in 96 waste sands from ferrous and non-ferrous foundries in Argentina were examined. While there were some exceptions, the majority of waste foundry sands contained metal concentrations similar to those found in virgin sands and native soils. Because naturally low metal concentrations were found in most waste sands, it is likely they could be beneficially used in a variety of applications without detriment to human and environmental health.
Technical Abstract: Waste molding and core sands from the foundry industry have been successfully used around the world as byproducts in geotechnical and agricultural applications. Although waste foundry sands (WFSs) are generally not considered hazardous in nature, relevant data are not available in Argentina. This study aimed to quantify metals in waste molding and core sands from foundries using a variety of metal-binder combinations. Metal concentrations in WFSs were compared to those in virgin silica sands (VSSs), surface soil and soil guidance levels according to hazardous waste law 24.051 from the Argentinean Secretariat of Environment and Sustainable Development. A total analysis for Ag, Al, Ba, Be, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Te, Tl, V, and Zn was conducted on 96 WFSs and 14 VSSs collected from 17 small and medium-sized foundries. The majority of WFSs analyzed, regardless of metal cast and binder type, contained elemental concentrations similar to those found in virgin sands and native soils. In several cases where alkyd urethane binder was used, Co and Pb concentrations were elevated in the waste sands. Elevated Cr, Mo, Ni, and Tl concentrations associated with the virgin sands should not be an issue since these elements are bound within the silica sand matrix. Because of the naturally low elemental concentrations found in most WFSs examined in this study, they should not be considered hazardous waste, thus making them available for encapsulated and unencapsulated beneficial use applications.