Spent foundry sand (SFS) from cast iron industry mixed with loess was characterized to recycle spent foundry sand as ceramic support materials. Since SFS mostly consists of sand including binding agents and residue [1], it was used as permeable media, and loess, which has highly adsorptive and reactive properties, was used as support materials . Leaching tests such as Korean Leaching Test (KLT) and TCLP (Toxicity Characteristics Leaching Procedure) showed that spent foundry sands from cast iron industry were not hazardous. Turbidity in furan sand was much higher than that in other sands, and turbidity was almost not changed with increasing amount of loess. The order of ORP (oxidation-reduction potential) in spent foundry sands was green sand > furan sand > CO2 sand. ORP was decreased with the amount of sand in furan sand and CO2 sand but was increased with the amount of sand in green sand. Hence, mixture of SFS and loess can be used as ceramic support materials with reductive or oxidative capability.