Abstract
Materials characterization is essential for both waste management, but also as the first stage in determining the potential for waste reprocessing as part of the circular economy. This paper describes in detail the multi-method characterisation of a filter press sulfur sludge sample from Boliden’s Harjavalta Smelter in Finland. This material represents the filter press cake precipitate after it has been clarified and filtered from the sulfuric acid plant. The sample was characterized geochemically and mineralogically, as well as for Acid Mine Drainage (AMD) potential. Magnetic and gravity separation process tests were also conducted to further investigate processing options for extracting any valuable metals. The study showed the sludge is chemically highly complex and mineralogically/materially challenging, mainly because of its extreme composition. In conclusion, it is suggested that a hydrometallurgical process path to neutralize this sample is the best way forward, which will be developed in future work.
| Original language | English |
|---|---|
| Article number | 109915 |
| Journal | Minerals Engineering |
| Volume | 236 |
| DOIs | |
| Publication status | Published - Feb 2026 |
| MoE publication type | A1 Journal article-refereed |
Funding
This project was funded by Business Finland, BATCircle 2.0 (grant ID: 44412/31/2020). We thank Jussi Pokki, and Sipi Seisko for the administration of the GTK part project. We thank the staff at Mintec for conducting this test work.
Keywords
- Automated mineralogy
- Filter press precipitate
- FTIR
- Gravity
- Harjavalta
- ICP
- Leco
- Magnetic
- Sludge
- Smelter
- Sulfur
- Waste
- XRD
- XRF