# Separation of Iron Oxide from Harbor Waste Using Selective Flocculation
## 3 Results
### SEM-EDS and XRD Analyses
Considering the previously stated observations, it is clear that the results of mineralogical determination obtained by X-ray powder diffraction analysis of the questioned material differ in relation to the phases that could be determined by EDS analysis performed in the form of point analysis. Figure 4 shows sample K1 with analyzed points and corresponding EDS spectra. It can be seen that the gray-colored grains are built only of carbon and oxygen, while the lighter phases present on the described grains are aluminosilicate with iron (spectrum 2) and iron oxide (spectrum 3). The mineral phases identified in the investigated samples by XRD and SEM-EDS analyses are shown in Table 4. X-ray diffraction analysis revealed the presence of magnetite in all magnetic fractions, while this phase was absent in non-magnetic fractions, which was expected. Hematite, gibbsite, and quartz are present in both fractions (Figure 5). Figure 2: SEM micrograph (BSE mode) of unpolished grains (sample K) with marked analyzed points: (**a**) spot chemical analyzes on one grains marked with 1, 2 and 3 and (**b**) point chemical analyzes on two grains marked with 4, 5 and 6. Results of SEM-EDS analysis in Table 5 are given based on individual points analysis on the chosen grains that showed homogeneity in composition. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Sample** & \multicolumn{2}{c}{**K1**} & \multicolumn{2}{c}{**K1M**} & \multicolumn{2}{c}{**K2**} & \multicolumn{2}{c}{**K2M**} & \multicolumn{2}{c}{**K3**} & \multicolumn{2}{c}{**K3M**} \\ \hline  & XRD & SEM & XRD & SEM & XRD & SEM & XRD & SEM & SEM & SEM & XRD & SEM \\ magnetite & & & + & & & + & & & & + & \\ hematite & + & & + & + & + & + & & & + & \\ quartz & + & & + & + & + & + & & & + & \\ gibbsite & + & & + & + & + & & (+) & + & (+) \\ calcite & + & (+) & (+) & (+) & (+) & (+) & + & \\ goethite & & + & (+) & (+) & (+) & & (+) & & \\ phyllosilicates & + & + & & & & + & + & & \\ dolomite & & & & & & + & & + & \\ barite & & & & & & & & & + \\ amphibe & + & & & & & & & & \\ sphalerite & & + & & & & & & & \\ talc & & + & & & & & & & \\ gypsum & & + & & & & & & & \\ amorphous matter & + & & & & & & & & \\ \hline \hline \end{tabular} Note: + mineral present, and (+) mineral probably present.  
\end{table} 
Table 5: Mineral phases identified in investigated samples by XRD and SEM-EDS analyses. Figure 3: SEM-BSE images of the selected samples (K1, K1M, K2, and K2M with magnification of 50\(\times\) and scale bar of 500 \(\upmu\)m, and K3 and K3M with magnification of 500\(\times\) and scale bar of 50 \(\upmu\)m). Figure 4: BSE image of sample K1 with the marked analyzed points and obtained EDS spectra. Figure 5: Diffractogram of sample K1. Legend: Qz—quartz, Hem—hematite, Cal—calcite, Gabs—gibbsite, Gth—goethite, and PS—phylosilicate. EDS analysis showed high and elevated concentrations of carbon in all analyzed samples. Individual grains consisting mainly of carbon and oxygen were also observed. X-ray analysis determined that the phase that most corresponds to amorphous matter is present only in sample K1. Its presence is clearly visible as a raised base line on the diffractogram itself (Figure 5). In general, the mineralogical composition of coal mainly includes phases such as quartz, muscovite, kaolinite, carbonates (calcite, dolomite, and siderite), oxides (magnetite and hematite), and pyrite, unless combustion has been carried out [18; 19; 20; 21; 22]. The presence of quartz, hematite, magnetite, calcite, dolomite, goethite, and layered silicates as the main phases, which may correspond to the composition of coal, is confirmed by X-ray analysis, with the fact that phases containing sulfur (e.g., sulfides) are missing in our samples. Gibbsite was also identified by this analysis, but its presence is unrelated to the previously described coal composition. The heterogeneous nature of the material is more noticeable after elemental EDS mapping. The results of the representation of dominant elements in the samples are shown in Figures 6-8.