3.1 Particle Size Analysis The particle size distributions of four types of mine residues are presented in Figure 2. The particle size of PT1 ranges from 0.47 to 724 µm, with broadly consistent cumulative curves across the analyzed sub-samples, although a slight deviation was observed in subsample C. The PT2 sample comprises particles ranging in size from 0.24 to 1258 µm, with minor deviations in the coarser fractions but overall consistent cumulative behaviour. The PT3 shows a distribution between 0.1 and 1000 µm, and PT4 shows a narrower size range from 0.316 to 181.97 µm, with cumulative curves very similar across the analyzed subsamples. Figure 2 – Particle size distribution of PT1, PT2, PT3, and PT4 determined by laser diffraction. 3.2 Chemical Composition Chemical composition analysis was performed to identify the major and trace elements present in the mine residues and to support the assessment of their potential valorization pathways. The analysis was done by X-ray fluorescence (XRF) at SECIL and FEUP (Figure 3).
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