Utilization of color change and image processing to evaluate the Waste Foundry Sand reclamation level

Abstract

Waste Foundry Sand (WFS) is the by-product of casting industries and is utilized to make molds. Some minerals, such as clay particles or chemical admixtures such as phenolic resins, are used to bond silica sand grains and shape the mold. Preventing environmental impacts such as WFS landfilling, many researches have been conducted to find an appropriate way for reclamation and evaluation of its cleaning. Due to the color changes during this process, image processing is helpful for an estimation of reclamation progress. In this paper, thermal reclamation method and Response Surface Methodology (RSM) are used as the most appropriate way of reclamation and design of experiments, respectively. Samples are heated at different temperatures for a variety of time durations. The color changes of samples are measured using image processing technique by detection of RGB (Red, Green, Blue) color coordinate system parameters changes (ΔRGB). The results of TCLP (Toxicity Characteristic Leaching Procedure) tests reveal that phenolic compounds are removed during the reclamation process, which causes WFS color changes from black to almost white. On this basis, a linear model is developed to predict RGB values relative to time or temperature variations. Results approve that an investigation on ΔRGB values provides a precise estimation of WFS grains reclamation level (less than 10 % error) to guide its reuse within the foundry industries.