## 3 Results and Discussion
### Analysis of Tailings Fractions
The XRD diffractograms are given in Figure 6, while the percentage compositions of fractions and crystal parameters are given in Figure 6 and Tables 6 and S4. From the obtained results, it can be concluded that the compositions of the different fractions is not uniform and there is a difference in the mineral contents. Also, the composition differs significantly from the starting JHC sample. The highest (\(-24\%\)) and the lowest (\(-13\%\)) amounts of albite were determined in fractions \(-200+100\) and \(-100+63\) um, respectively. The highest amount of biotite (\(-14\%\)) was in the fraction \(-100+63\) um, while highest amount of calcite was in the fraction \(-63+0\) and \(-100+63\) um. Auxiliary minerals such as quartz and clinochlore were mostly present (more than 50%) in this sample regardless of the particle size and fraction. Considering that, the results presented in Table 6 show that the most prevalent is fraction \(-63+0\) um (91.33%), and it can be concluded that the extraction of useful minerals will be cost-effective from this fraction. In general, materials with the smallest particle size are the most problematic for their potential application in various technological processes. The fraction \(-63+0\) um is significantly present in all three samples (91.33% for JHC, 33.27% for JOF and 16.73% for JKB). For that reason, it was of interest to determine the composition of fractions with the finest degree of granulation. For that purpose, the JKB, JOF and JHC samples were additionally sieved and the mineralogical composition of the fraction with a particle size of \(-10+0\) um was examined. The contribution of this fraction was not negligible for JOF (10.11%) and JHC (15%), while for JKB, it was only 3.2%. However, to compare results, all three samples were analyzed with XRD and the results are presented in Figure 7 and Tables 7 and S5. It may be noted from Figure 7 that for all three samples, the changes in phase composition are not uniform in comparison with the starting samples (Figure 2b). All phases in the starting JKB, JOF and JPH samples were detected in this fraction, but in a different relation. For the JKB sample, in the fraction \(-10+0\) um, the contents of the quartz (\(-8\%\)), calcite (\(-10\%\)) and pyrite (\(-1\%\)) were lower, while the content of the biotite (\(-4\%\)), clinochlore (\(-38\%\)) and albite (\(-40\%\)) were higher in comparison with the starting sample. For the JOF sample, the content of the albite, calcite, biotite and pyrite was approximately equal to the content in the starting sample, while the content of quartz (\(-7\%\)) was lower and clinochlore (\(-42\%\)) was higher. For the JHC sample, in the fraction \(-10+0\) um, only the content of the albite (\(-48\%\)) increased, and the content of quartz (\(-7\%\)) decreased, while the content of other mineral phases was approximately equal as in the starting JHC sample. From the presented results, considering the presence of this fraction (Table 3), it can be concluded that the extraction of useful minerals will be cost-effective from this fraction only in JHC and JOF. After the identification of fractions in which the contents of useful minerals are the highest, it is possible to further extract them by using appropriate techniques. For example, albite and biotite may be extracted and separated from useless minerals by using gravity and magnetic separation techniques [27], and calcite by using flotation technique and anionic/cationic collectors [28]. Regarding the application of useful minerals, they are used in various industrial processes. _Calcite_ can be used in non-ferrous metals and minerals, iron and steel, chemicals, portable water, pulp and paper, oil & gas, cement and construction, agriculture, animal husbandry and aquaculture, as well as in wastewater and sludge treatment, sugar refining, flue gas treatment, glass and ceramics, road and soil stabilization, food preparation, supplements and many more. Specifically in the construction industry, calcite plays an important role in concrete.