SPL‐CYCLE: Closing the loop of the Spent Pot‐line (SPL) in Al smelting process

Research Project, 2018 – 2021

Each ton of aluminium produced in Al smelters generates approx. 20kg of hazardous waste, which is a mix of the carbon lining and the refractory lining, known as "spent pot lining" (SPL). Worldwide aluminium production in 2016 was approximately 59 million tonnes, corresponding to the generation of 1.18 million of tonnes of SPL. The current practice of the waste management of hazardous SPL is landfilling or incineration, which costs aluminum producers on average 200 EUR/tonne (240 million EUR annually on a global level).

The project presents a novel zero waste technology for the recycling of spent pot lining (SPL) from aluminum production, consisting of four main separation on processes (preparation, extraction, flotation, and refining) in order to achieve the quality of products needed by end‐users. The final products will be used either in aluminum production (recovered carbon and fluoride slats) or will be sold to the refractory industry or the construction industry (recycled refractory residues). A pilot demonstration of the operability of the system will be constructed at the company in Slovenia, with the aim of optimizing and valorizing the technology. Additionally a reliable business model will be developed enabling the next steps to commercialization.

The innovative technology itself and the new sustainable approach will therefore represent a new circular economy business model for aluminum producers with the complete elimination of waste deposition and incineration costs.