## 3 Materials and Methods  
### Sampling and Waste Processing  
The sampling of granite extractive waste was carried out at 18 points within the quarry extraction area, aiming to collect material from different landfill locations. Material at the sampling points was initially reduced in size using a pneumatic percussion hammer to increase the volume of collected material and enhance the representativeness of the samples. At the end of the sampling campaign, 18 samples were obtained, each weighing between 3 and 7 kg. The samples were then processed at the laboratories of the University of Ferrara (Figure 2): samples were further reduced in size using a saw equipped by diamond cutting disc to facilitate the crushing operations in the laboratory. Crushing operations were then carried out for each sample using a jaw crusher. An aliquot was taken from each crushed sample, by quartering, to perform compositional analyses of the whole rock. The material was then sieved to retain the particle size range between 850 \(\upmu\)m and 125 \(\upmu\)m. Material below 125 \(\upmu\)m was considered as crushing powder and was not subjected to further processing to extract the constituent minerals by gravity and magnetic methods, but was instead sampled, by quartering, for compositional analyses. Subsequently, 9 out of the 18 samples were used for the separation tests of the various phases constituting the granite waste: firstly, each sample underwent a gravity separation using a wet shaking table Gemini Masa G-150 (Onur Makina, Eskisehir, Turkey). This process was conducted to concentrate the higher specific gravity minerals. At this stage, a 1:1 weight ratio mixture of granite waste to water was prepared. The latter was introduced into the feed container, and the feed control tap was opened to 1/3 of its total opening. The shaking frequency was set to \(\sim\)250 strokes per minute, while all the water dispensers on the table were left open. At the end of this phase, three sub-samples were obtained from each processed sample, representing the following fractions: low specific gravity (light), intermediate specific gravity (intermediate), and high specific gravity (heavy). The materials thus obtained were dried in an oven at 105 \({}^{\circ}\)C until completely dry and subsequently weighed by means of a scale. After this phase, ferromagnetic minerals were removed, using a magnet, from each sub-sample. This operation was carried out to facilitate the following magnetic separation phase and to prevent equipment clogging. For the latter phase, the sub-samples belonging to the light fraction were quartered due to a high amount of material, in order to perform magnetic separation operations on a representative fraction of each sub-sample. The instrument was set to have a side tilt of \(\sim\)15\({}^{\circ}\) and a forward tilt of \(\sim\)20\({}^{\circ}\). The magnetic separation was conducted using an isodynamic magnetic separator L-1 (S.G. Frantz Co., Tullytown, PA, USA). The magnetic separation occurred in two phases: in the first phase, minerals with higher magnetic susceptibility were separated by applying a magnetic field of \(\sim\)4 kG (\(\sim\)0.4 A); in the second phase, the remaining portion underwent subsequent separation applying a magnetic field of \(\sim\)18 kG (\(\sim\)1.6 A) to separate phases with low magnetic susceptibility. At the end of the magnetic separation, 3 additional sub-samples were obtained for each representative sub-sample, representing the following phases: diamagnetic phase, high-susceptibility paramagnetic phase, and low-susceptibility paramagnetic phase. The sub-samples were then weighed to calculate the yield percentages relative to the initial sample.