Emission reduction potential in thermal reclamation of waste foundry sand

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Insinööritieteiden korkeakoulu | Master's thesis
Mechanical Engineering
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Master's Programme in Mechanical Engineering (MEC)
In recent years, environmental impacts of waste foundry sand have received much attention in the foundries of European countries due to the large quantity of waste sand, especially green sand that is used around 75% of the total sand in foundries. The additional reasons are possible large environmental impacts and stricter environmental regulations for achieving net-zero emissions by 2050 in the EU. Thermal reclamation is one of the effective methods to reclaim waste foundry sand for reusing in foundries. Despite its advantages, thermal reclamation consumes a large amount of energy. Greenhouse gas emissions of thermal reclamation should be assessed following the EU environmental regulations. The thesis aims to evaluate the greenhouse-gas emission reduction potential of Finn Recycling’s thermal sand reclamation by comparing the reclamation emissions to the emissions of virgin sand processes in Finland, the Czech Republic, Germany, Italy, and Sweden. An additional thesis aim is to propose solutions for emission reduction based on the calculated results. Therefore, this thesis used a life cycle assessment (LCA) method with global warming impact to calculate greenhouse gas (GHG) emissions of virgin sand and thermal reclamation processes of waste green sand in five countries before comparing the results. Based on the results, the thermal reclamation processes have GHG emission reduction potential over the virgin sand processes in all countries. This is mainly because their virgin sand processes produced high emissions from sand excavation and processing as well as long-distance transport. In addition, reclaiming sand emitted the highest emission in the reclaimed-sand system. Therefore, this process should be focused on reducing GHG emissions and increasing the reclaimer efficiency. The proposed solutions could be using a greener fuel source or electricity in the furnace, optimizing the combustion parameter, as well as implementing advanced technology like microwave reclamation. This study would help develop the sand reclaimer and environmental management for sustainability in the foundry.
Orkas, Juhani
Thesis advisor
Sappinen, Tommi
Nissinen, Maarit
waste foundry sand, green sand, life cycle assessment, global warming, greenhouse gas emissions, thermal reclamation
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