Industrial Treatment Processes For The Recycling Of Green Foundry Sands
Free (open access)
S. Fiore & M. C. Zanetti
Three treatment processes for the reclamation of green moulding sands coming out from a cast iron foundry located in Northern Italy are considered in this study. A wet mechanical treatment, a dry mechanical treatment and a dry mechanical plus thermal treatment are compared to evaluate the efficiency of each process and to point out the best regeneration solution for the recycling of reclaimed sand in foundry operations. The inflow and the outflow samples of each process were characterized by means of particle-size analysis and the determination of silica, loss on ignition, acid request, oolitic and some metals contents. A final evaluation of the three processes was performed taking into account the obtained quality of recovered silica sand and the economical aspects; the wet mechanical and the dry mechanical plus thermal treatments are the most effective for the recovery of green moulding sands coming out from Teksid foundry plant for cold-box core production. Keywords: bentonite bonded moulding sand, green sand, foundry waste recycling. 1 Introduction Exhaust sands represent a crucial issue in the management of foundry wastes: a ferrous foundry of secondary fusion produces an amount of wastes varying from 25% to 100% b.w. respect to the final product, and the 30-60% of these wastes is made of core and moulding sands (EPA ). Therefore the optimization of processes aimed to the recycling of exhaust foundry sands is particularly interesting.
bentonite bonded moulding sand, green sand, foundry waste recycling.