## 3 Results and Discussion
### Chemical Analyses and Leaching Results
Previous studies on EAF slags [9] and converter slags from the basic oxygen steelmaking process [7; 8; 39] showed that larnite/dicalcium silicate may contain V and that this phase is highly soluble. Therefore, a modification to less soluble Fe bearing olivine, melilite, and pyroxene phases due to an increased SiO\({}_{2}\) concentration in the molten slag additionally minimizes V leaching. The remelted slag samples BR1-3 released more V during the performed pH dependence leaching tests than the original sample B, which is in accordance with the increased FeO/SiO\({}_{2}\) ratio of above four after the experiments (Figure 5 and Table 1). For Cr, the pure remelting of sample B had a greater effect than the combined remelting and SiO\({}_{2}\) addition. However, all modified samples met the limit value for Cr, according to the recycling building materials ordinance in Austria (0.3 mg/kg DM; [14]). The melting experiments and the performed leaching tests illustrate that the leaching behavior of V and Cr does not correlate with the total content in the slag, but is controlled by the mineralogical binding of the elements. This becomes evident because, despite the high total contents of Cr (up to 3 mass-%), only a small proportion of Cr is released during leaching with distilled water; whereas comparatively high amounts of V are released, although the total concentration of V is about 0.1 mass-%. In addition, the leaching behavior was improved by changing the mineral phase composition and distribution (e.g., formation of less soluble calcium silicate phases) in the modified slag samples. Figure 5: pH-dependent leaching behavior. (**a**) Cr, (**b**) V, (**c**) Ca, and (**d**) Si for original samples A, B, C and remelted samples BR1–3 as well as for remelted and modified samples BC1–3. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multicolumn{10}{c}{**Leached Concentrations with Distilled Water**} & \multicolumn{4}{c}{**Total Concentrations**} \\ \hline  & \multicolumn{4}{c}{**[\% of Total Content]**} & \multicolumn{2}{c}{**[mg/kg DM]**} & \multicolumn{4}{c}{**[mass-\%]**} & \multicolumn{2}{c}{**Ratio**} \\ \hline
**Sample** & **pH** & **Cr** & **V** & **Cr** & **V** & **Cr2O3** & **V2O3** & **MgO** & **Al2O3** & **FeO/SiO2** & **CaO/SiO2** \\ \hline A & 11.2 & \(1.1\times 10^{-40}\) & 0.34 & 0.13 & 2.5 & 1.73 & 0.11 & 6.20 & 7.28 & 3.66 & 2.03 \\ AR1 & 11.0 & \(6.4\times 10^{-40}\) & 0.19 & 0.076 & 1.2 & 1.72 & 0.09 & 6.53 & 8.26 & 3.26 & 1.54 \\ AR2 & 10.8 & \(2.9\times 10^{-65}\) & 0.06 & 0.0024 & 0.37 & 1.20 & 0.08 & 6.45 & 7.58 & 3.35 & 1.89 \\ AR3 & 10.9 & \(9.0\times 10^{-60}\) & 0.07 & 0.0018 & 0.38 & 2.98 & 0.08 & 7.23 & 7.18 & 3.83 & 1.59 \\ ACI & 10.1 & \(8.8\times 10^{-40}\) & 0.03 & 0.046 & 0.13 & 0.76 & 0.06 & 13.9 & 6.61 & 1.12 & 0.57 \\ AC2 & 10.0 & \(6.0\times 10^{-65}\) & 0.01 & 0.0043 & 0.019 & 1.03 & 0.05 & 12.6 & 6.73 & 1.21 & 0.60 \\ AC3 & 10.1 & \(6.7\times 10^{-40}\) & 0.01 & 0.0024 & 0.025 & 0.52 & 0.05 & 13.1 & 6.48 & 1.05 & 0.57 \\ B & 11.9 & \(1.5\times 10^{-40}\) & 0.02 & 0.019 & 0.12 & 1.86 & 0.11 & 3.47 & 9.58 & 3.42 & 2.38 \\ BR1 & 11.5 & \(1.1\times 10^{-40}\) & 0.19 & 0.013 & 1.2 & 1.81 & 0.09 & 3.79 & 8.35 & 4.71 & 2.54 \\ BR2 & 11.5 & \(5.7\times 10^{-40}\) & 0.17 & 0.0077 & 1.0 & 1.97 & 0.09 & 3.82 & 8.67 & 4.76 & 2.62 \\ BR3 & 11.5 & \(3.5\times 10^{-40}\) & 0.11 & 0.0049 & 0.65 & 0.20 & 0.09 & 3.82 & 9.24 & 4.80 & 2.65 \\ BCI & 10.7 & \(2.6\times 10^{-40}\) & 0.09 & 0.026 & 0.38 & 1.45 & 0.06 & 7.13 & 7.14 & 1.24 & 0.69 \\ BC2 & 10.5 & \(1.3\times 10^{-40}\) & 0.04 & 0.012 & 0.15 & 1.36 & 0.06 & 8.42 & 6.80 & 1.20 & 0.65 \\ BC3 & 10.4 & \(9.2\times 10^{-65}\) & 0.02 & 0.0081 & 0.081 & 1.29 & 0.06 & 8.07 & 6.78 & 1.25 & 0.65 \\ C & 10.8 & \(2.4\times 10^{-65}\) & 0.03 & 0.0035 & 0.37 & 2.13 & 0.16 & 3.92 & 9.13 & 1.04 & 0.94 \\ \hline \hline \end{tabular}
\end{table}