Blasting of surfaces such as ships, tanks, and steel plates to remove old coatings generates used blasting sand. The composition of this sand varies depending on the surface treated, but typically contains high levels of heavy metals.
Sandblasting waste that includes hazardous substances must be handled as hazardous waste. Today, used blasting sand is primarily disposed of in landfills, which may contribute to the spread of environmental pollutants and is not considered a sustainable long-term solution.
There is therefore a need to develop effective methods for managing and potentially recovering this waste, in order to reduce environmental impact, ensure safe disposal, and identify new possible applications.
This project aims to test a process at Attvin Næring AS’s metal sorting facility that may help reduce the heavy metal content in used blasting sand by separating the metals into a distinct fraction.
If successful, the method will lower the concentration of hazardous substances, meaning the sand may no longer need to be classified as hazardous waste. This would not only reduce the volume of hazardous waste requiring disposal but also open up opportunities for sustainable use of the material.
Metal separation can be achieved in various ways using different techniques. If the particles are large (> 0.5 mm), separation can be performed through physical unit operations. In this project, physical separation by fractionation based on magnetism and induced magnetism will be tested.
Documented reduction of heavy metals following separation may help guide potential reuse, while also enhancing resource utilization and value creation.
Header image: Used blasting sand. Photo: Stine Steen/SINTEF Nordvest (background extended with Adobe Firefly).