ARS | Publication request: Use of an integrated approach to characterize the physicochemical properties of foundry green sands

Submitted to: Thermochimica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 30, 2012
Publication Date: July 9, 2012
Citation: Carnin, R., Folgueras, M.R., Luvizao, R., Correia, S., Da Cunha, C., Dungan, R.S. 2012. Use of an integrated approach to characterize the physicochemical properties of foundry green sands. Thermochimica Acta. 543:150-155.

Interpretive Summary: Each year foundries around the world generate millions of tons of spent foundry sand that are generally discarded in landfills without further use. In this study, sands from an iron foundry were physically and chemically characterized to understand how the properties change during the casting process and after time in a landfill. The sands investigated in the study were green sands; these sands are coated with clay and coal prior to the casting process. While the casting process generally does not affect the properties of the sands, it was found that the coating materials were all but absent after spending two years in a landfill. It is possible that the landfill sands could be reclaimed for use in the foundry or other beneficial use applications, such as cement, asphalt, and manufactured soils. Diverting residuals from landfills, like spent foundry sands, can help minimize the environmental impacts associated with the mining of virgin sands.

Technical Abstract: A fresh green sand, spent green sand, and a weathered spent green sand from a landfill were analyzed using diffractometry, electron microscopy, granulometry, spectrometry, and thermogravimetry. Our objective was to understand how the physicochemical properties of the green sands change from their original form after being subjected to the casting process, then after weathering at the landfill. A quantitative phase composition model was also postulated for each material based on thermogravimetric results and it was found to be the most reliable and informative quantitative data for this type of residue. The weathered sample, that remained in a landfill for two years, was found to be composed of almost pure sand. Because of the weathering process, it may be possible to use the wSGS as a virgin sand replacement in the regeneration system or in geotechnical applications where bentonite would affect the properties of the final product.