Submitted to: Near Infrared Spectroscopy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 13, 2006
Publication Date: May 1, 2007
Citation: Dungan, R.S., Reeves III, J.B. 2007. Near Infrared Spectroscopic Analysis of Foundry Moulding and Core Sands. Near Infrared Spectroscopy Journal. 15(3):189-194.
Interpretive Summary: Sands coated, mixed and polymerized with a wide variety of materials are used to make molds for the casting of metals. Heating results in a wide variety of organic materials being produced by pyrolysis, which may need to be quantified before waste sand can be beneficially used in the environment. Present methods for determining organics, such as the Toxicity Characteristic Leaching Procedure followed by mass spectrometry, are expensive and time consuming. As waste foundry sands contain very little organic matter (> 90% silica sand) they represent a very different type of material from the highly organic materials for which near-infrared spectroscopy (NIRS) is generally used. The objective of this work was to examine the potential of NIRS for both qualitative and quantitative analysis of waste green sands (clay-bonded molding sand). Examination of spectra of waste green sands, burnt and unburnt cores and components used in producing sands used by the foundry industry have demonstrated that NIRS has potential for use to: 1) confirm the identity/composition of source materials; 2) identify the process used in producing the waste green sands; and 3) quantify the amounts and composition of organics present in waste green sands. Finally, results showed that the spectral properties of waste foundry sands are considerably different than non-organic coated sands due to changes in the overall spectral reflectance of the sand.
Sands used by the foundry industry for metalcasting are coated with a variety of organic materials. During the casting process, the organic materials are thermally degraded, producing a wide variety of potentially harmful organic byproducts. Because there is great interest in beneficially using waste foundry sands as an aggregate in agricultural products, the detection and quantification of organics is necessary. Because current methods for determining organics are often very time consuming and expensive, alternative methods that are rapid and cost-effective are needed. One such analytical technique is known as near-infrared spectroscopy (NIRS). Analysis of waste foundry sands using NIRS revealed that this technique may be useful to identify and quantify organics. Successful implementation of NIRS would ensure that foundry sands are safe for use in the environment.