Development of energetic model for dry mechanical reclamation process of used foundry sands

Abstract

A systematic approach to analyse the reclamation of used foundry sands is proposed. The development of an energetic model for dry mechanical reclamation of used foundry sands is described. The theoretical basis of the model is the Rittinger hypothesis for crushing minerals, which balances the energy input for reclamation against the energy consumed in creating additional surface area as the average size of the used sand agglomerates is reduced. The Rittinger number is known for pure silica, which has properties close to those of quartz sand grains. It is shown that information from routine grain size analysis, performed by sieving during reclamation, can be used to calculate the Rittinger number for binder materials, assisting in optimisation of the dry reclamation process. Processing at cryogenic temperatures (−80°C) increases dry reclamation efficiency and produces reclaimed sands with better technological parameters, but must be closely controlled to prevent excessive dusting.