Comparing Sands From Different Reclamation Processes for Use in the Core Room of Cylinder Heads and Cylinder Blocks Production

Abstract

The use of reclaimed sands in the cold-box core room is discussed, comparing three different reclamation processes. The first is called a thermal process that treats resin-bonded sand in a hot fluidized bed. The second is a wet process, removing bentonite and coal dust from green sand with water and attrition treatments. The third is a mechanical–thermal–mechanical process (pneumatic–hot fluidized bed–pneumatic), operating with a mixture of green sand and resin-bonded sand. The experimental study, in the laboratory and with foundry trials, shows that all processes result in some impurities in the sand that bring some changes in the core properties. Residues from core coatings, from bentonite and from decomposed seacoal, can lower the core strength and the bench life; at the same time, some of the residues can improve hot properties of the core, reducing veining tendency and core deformation. Therefore, some reclaimed sands can be used as special additives in the core room.