Recycling of waste foundry sands by chemical washing method

This study aims to remove the metals (inorganic and heavy metals) in waste foundry sand (WFS) via chemical washing method. Washed waste foundry sand (WWFS) samples were obtained by using triptych washing successively with 5 M HCl, 5 M H2SO4 and 5M NaOH solutions. Analysis on functional groups, micropores, heavy metals, and inorganic components of WFS and WWFS was carried out by using FT-IR, SEM and XRF. Results show that the concentration values of some inorganic components such as Ca, Fe, Mg, S were decreased, and the maximum removal percentage of these inorganic components are 47%, 19%, 32%, and 8%, respectively. The concentration values for each of the heavy metals of WWFS are below of limit values given in App-3 List of Regulation on General Principles of Waste Management. The removal percentages of Pb, As and Zn elements are 100%, 71%, and 40%, respectively. The findings of this research suggest that WWFS can be used in more applications due to its ability to remove heavy metals and some other inorganic components.