Influence of Sand Properties on Core Production Quality and Performance

Abstract This study examined the chemical and mechanical behaviour of fresh silica sand, green sand-related materials, and mechanically reclaimed sand used in cold-box core production. The work was conducted in the context of sand regeneration in an automotive foundry producing cast iron components. Reclaimed sand was collected from a defined point in the mechanical regeneration cycle after attrition and dedusting. The sand was then analysed by pH and electrical conductivity measurements to evaluate remaining contamination. The finest reclaimed fractions showed the highest pH and conductivity, which indicates that alkaline residues and dissolved ions were concentrated in the small-grain portion. Comparison between fresh sand, green sand mixtures, and reclaimed sand showed that the reclaimed material behaved chemically like a fresh sand mixture containing up to about 10% green sand residue. When the share of reclaimed sand increased, pH and conductivity increased, and the 1-hour bending strength decreased. These results show that the chemical condition of reclaimed sand, especially its fine fraction, has a direct effect on final core strength. Regular monitoring of reclaimed sand chemistry is, therefore, important for stable cold-box production and consistent core quality.