# Micro-Raman Spectroscopy Investigation of Crystalline Phases in EAF Slag
## 3 Results and Discussion  
### Sem-Edx  
Chemical and morphological analyses were performed on each sample. In Figure 1 the SEM micrographs of samples A are shown. The growth of the crystalline phases within steel waste is strongly affected by the cooling speed and the addition of additives during the deslagging step (for example SiO\({}_{2}\)) [6; 14; 15]. Due to the slow cooling rate, sample A is characterised by well-developed grains. Instead, sample D is characterised by white dendritic structures, due to the high cooling speed and the addition of silica during the deslagging. Samples B, C and E are characterised by grains of similar size, because of the similar cooling treatment (see Table 1). The grain colours range from white to dark grey. Each colour shade corresponds to different compositions, as discussed in our previous work [16]. EDXS results are reported in Table 3. Because of the large grains, sample A was chosen as a reference sample for the phase identification. SEM micrographs and EDXS results of samples B, C, D and E are reported in the Supplementary Materials.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Area**} & \multirow{2}{*}{**Position**} & \multicolumn{8}{c}{**Atomic\%**} & \multicolumn{8}{c}{**Phase**} \\  & & & **O** & **Mg** & **Al** & **Si** & **Cl** & **Ca** & **Ti** & **V** & **Cr** & **Mn** & **Fe** & **Ba** & **W** & \\ \hline \multirow{8}{*}{A} & 1 & 51.4 & - & 12.6 & - & - & 25.0 & - & 0.9 & - & - & 10.1 & - & - & Brownmillerite \\  & & 2 & 52.6 & - & 0.4 & 16.0 & - & 30.3 & - & 0.3 & - & - & 0.4 & - & - & Lamine \\  & 3 & 40.4 & 9.7 & - & - & - & 6.4 & - & - & 0.4 & 8.5 & 34.6 & - & - & Magnesiosierrite \\  & 4 & - & - & - & - & - & - & - & - & - & - & 100.0 & - & - & Iron \\  & 5 & 50.6 & - & 13.0 & - & - & 24.4 & - & 1.0 & 1.2 & 0.4 & 9.4 & - & - & Brownmillerite \\  & 6 & 41.2 & - & 1.4 & - & 4.6 & 12.4 & - & 10.2 & - & - & 5.3 & 22.0 & 3.0 & * \\ \hline \multirow{8}{*}{A} & 1 & 50.8 & - & 8.5 & 3.6 & - & 25.4 & - & 0.6 & 5.5 & - & 5.6 & - & - & Brownmillerite \\  & 2 & 43.54 & 13.56 & - & - & - & 6.12 & - & - & 0.71 & 7.7 & 28.7 & - & - & Magnesiosierrite \\  & 3 & 50.7 & - & 11.4 & - & - & 2.42 & - & 0.6 & - & 6.3 & - & 6.8 & - & Brownmillerite \\  & 4 & 42.0 & 12.1 & - & - & - & 4.56 & - & - & 0.58 & 8.84 & 31.95 & - & - & Magnesioferrite \\  & 5 & - & - & - & - & - & 0.7 & - & - & - & - & 99.3 & - & - & Iron \\  & 6 & 49.4 & - & 10.9 & 0.6 & - & 24.7 & 0.4 & 0.7 & 6.3 & - & 7.1 & - & Brownmillerite \\  & 7 & 40.8 & 12.6 & - & - & - & 3.1 & - & - & - & 10.1 & 33.4 & - & - & Magnesioferrite \\  & 8 & 40.5 & 14.7 & - & - & - & 2.5 & - & - & 0.4 & 10.4 & 31.4 & - & - & Magnesioiferrite \\  & 9 & 51.4 & - & 9.9 & - & - & 23.9 & 0.4 & 0.6 & 6.0 & 0.6 & 7.3 & - & - & Brownmillerite \\  & 10 & 52.9 & - & 15.9 & - & 30.8 & - & - & - & - & 0.4 & - & - & Lamine \\ \hline \multirow{8}{*}{B} & 1 & - & - & - & - & - & 0.87 & - & - & - & - & 99.1 & - & - & Iron \\  & 2 & - & - & - & - & 1.3 & - & - & - & - & - & 98.7 & - & - & Iron \\  & 3 & 52.7 & - & 10.5 & - & - & 23.1 & 0.4 & 0.6 & 6.0 & - & 6.8 & - & - & Brownmillerite \\ \cline{1-1}  & 4 & 52.9 & - & 11.0 & - & - & 23.48 & - & 0.7 & 4.4 & - & 7.6 & - & - & Brownmillerite \\ \cline{1-1}  & 5 & 42.9 & 14.1 & - & - & - & 3.54 & - & - & 1.4 & 8.4 & 29.7 & - & - & Magnesioferrite \\ \cline{1-1}  & 6 & 47.1 & 11.1 & - & - & - & 8.57 & - & - & 6.5 & 26.8 & - & & - & Magnesioferrite \\ \cline{1-1}  & 7 & 52.8 & - & - & 16.0 & - & 30.29 & - & 0.4 & - & 0.6 & - & - & Lamine \\ \cline{1-1}  & 8 & 54.2 & - & - & 15.6 & - & 30.21 & - & - & - & - & - & - & & Lamine \\ \hline \hline \end{tabular}
\end{table}
Table 3: EDXS analysis of sample A (molar%) in the points indicated in Figure 1 and the predicted crystalline phase.