Investigations of Industrial Mineral Residues with the Aim of Maximizing the Utilization of the Contained Mineral Phases

This study investigates the beneficiation potential of Schlicker, a fine-grained by-product from leucophyllite processing at Aspanger Bergbau and Mineralwerke GmbH in Lower Austria. With approximately 2 million tonnes stored in intermediate storage ponds and 10,000 tonnes generated annually, effective utilization of this muscovite-quartz mixture represents a significant economic opportunity. Comprehensive characterization revealed that 40 wt% of particles are finer than 40 µm, with an inverse relationship between particle size classes and density. The finest fraction (<32 µm) contained the highest muscovite concentration (58.4 wt%) and density (2.88 g/cm3), while coarser fractions are dominated by quartz. Microscopic observations confirmed the presence of pyrite and iron hydroxides as major heavy minerals. Separation experiments using a Frantz isodynamic separator, Carpco induced roll magnetic separator, and shaking table demonstrated varying degrees of success. Magnetic separation effectively removed iron-bearing minerals and clinochlore, while the shaking table successfully concentrated heavy minerals, including pyrite, but showed limitations in separating clinochlore. The combination of lower shaking rates (350-400 rpm) and higher transverse angles (4.1°-4.5°) was identified as providing better separation of heavy minerals. The results indicated that a shaking table is essential as a pre-processing step to prepare an enhanced feed for further beneficiation. This research provides essential groundwork for developing viable strategies to process Aspanger Schlicker into marketable industrial mineral products.