Economic and Environmental Aspects of Applying the Regeneration of Spent Moulding Sand

This article presents issues related to the rational management of foundry sand in the context of sustainable development. Attention was drawn to the need to take appropriate measures to protect available natural deposits of good foundry sands in terms of their depletion. The main objective of the analyses undertaken was to find out whether more expensive but more efficient thermal regeneration can compensate for the higher energy consumption in relation to mechanical regeneration of spent moulding sand with an organic binder. This aspect was considered from the point of view of the multiple operations performed to clean the grain matrix from the spent binder, taking into account the direct and indirect costs of the process. This paper presents a comparative analysis of the mechanical and thermal regeneration of spent moulding sand on equipment offered by an exemplary manufacturer. Attention was drawn to the successively increasing price of the regeneration process. When analysing the grain matrix recovery process for sustainability reasons, attention was drawn to an important factor in grain matrix management related to its yield in different regeneration methods. Based on an analysis of the costs of regenerating 1 tonne of spent moulding sand, it was concluded that, in the long term, thermal regeneration, which is more expensive due to the cost of equipment and energy consumption, can offset the outlay incurred. Sand consumption was found to be 4.6 times higher by mechanical regeneration in the case studied. At the same time, the grain matrix after thermal regeneration was found to have significantly better and more stable technological parameters in subsequent sand mould preparation cycles. The reproducibility and stability of the technological process can also be an important component of economic growth as part of sustainable development.