# Grain Size Effect in Elution Test of Electric Arc Furnace Slag
## 3 Results
### Leaching Test
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **A** & **B** & **C** & **D1** & **E1** & **F** & **G** \\ \hline
**Elements** & & & & & **Conc. [mg/L]** & & & \\ \hline Si & 1.3 & 1.0 & 0.2 & 8.0 & 11.8 & 7.8 & 0.7 \\ P & 0.01 & 0.005 & 0.005 & 0.01 & 0.008 & 0.008 & 0.006 \\ K & 0.3 & 0.08 & 0.2 & 0.7 & 5.3 & 1.0 & 3.0 \\ Ca & 58.2 & 84.6 & 152.2 & 27.6 & 21.9 & 29.7 & 66.5 \\ V & 0.1 & 0.03 & 0.01 & 0.1 & 0.06 & 0.2 & 0.03 \\ Cr & 0.002 & 0.02 & 0.004 & 0.001 & - & 0.006 & 0.001 \\ Mn & 0.001 & 0.001 & 0.001 & 0.001 & 0.001 & 0.001 & 0.002 \\ Fe & 0.02 & 0.02 & 0.03 & 0.004 & 0.005 & 0.004 & 0.02 \\ Co & 0.005 & 0.005 & 0.02 & - & 0.004 & - & 0.01 \\ Cu & - & - & - & - & - & 0.001 & - \\ Zn & 0.01 & 0.01 & 0.01 & 0.006 & 0.007 & 0.002 & 0.01 \\ Se & 0.007 & 0.009 & 0.01 & 0.004 & 0.01 & 0.007 & 0.01 \\ Rb & 0.01 & 0.02 & 0.01 & 0.02 & 0.03 & 0.01 & 0.02 \\ Sr & 0.1 & 0.1 & 0.5 & 0.1 & 0.2 & 0.1 & 0.1 \\ Mo & 0.07 & 0.06 & 0.07 & 0.05 & 0.2 & 0.06 & 0.2 \\ Cd & - & - & - & - & - & - & - \\ In & 0.003 & 0.001 & 0.002 & 0.003 & - & 0.002 & 0.002 \\ Ba & 0.6 & 0.2 & 2.0 & 0.5 & 0.8 & 0.2 & 1.1 \\ Pb & 0.005 & 0.004 & - & 0.005 & 0.003 & 0.004 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: ICP-AES measurements results on leachate according to EN12457 2. To confirm the grain sizes effect on the leaching test, samples B, C, D1 and E1 were selected and their 4 mm granularity specimens were sieved and partitioned in nine granularity fractions. Finally, the leaching test procedure was performed on each fraction. Because of the high number of leachates, for the elemental analysis, the fast and cheap Total reflection X-ray fluorescence (TXRF) technique was used. We considered Ca, Zn, Sr, V and Ba, whom concentration can be reliably determined (comparison among ICP-AES and TXRF data is reported in Supplementary Material Table S4). The TXRF results of the nine fractions are reported in Figure 3 (all the data are reported in Supplementary Material Table S5). For each element, the concentrations have been normalized to the maximum obtained in the nine fractions. In samples B and C, the general trend confirms that the leaching of the elements arises when the grain size decreases, except in the case of V and Zn for sample B, that have an opposite trend. In sample D1 and E1, the monotone behavior is not clear. Both these results suggest a different phase composition of the fractions, as supported by XRD analysis (see Supplementary Material Figure S2). We suggest that the different percentage of the crystalline phases in the fractions can be determined \begin{table}
\begin{tabular}{c c c} \hline  & **Sample D1-D2** & **Sample E1-E2** \\ \hline
**Elements** & **Conc. [mg/L] (RSD%)** \\ \hline Si & 8.8 (12.8) & 12.6 (8.9) \\ P & 0.01 (0.5) & 0.007 (18) \\ K & 0.6 (21.2) & 4.7 (18.3) \\ Ca & 27.3 (1.8) & 27.2 (27.3) \\ V & 0.14 (18.2) & 0.08 (25.9) \\ Cr & 0.002 (38.6) & 0.0005 (141.4) \\ Mn & 0.001 (6.7) & 0.001 (23.4) \\ Fe & 0.003 (27.8) & 0.003 (84.4) \\ Co & - & 0.003 (39.5) \\ Zn & 0.003 (129.2) & 0.007 (7.6) \\ Se & 0.004 (3.7) & 0.01 (27.5) \\ Rb & 0.01 (23.8) & 0.03 (9.1) \\ Sr & 0.11 (25.4) & 0.19 (22.9) \\ Mo & 0.05 (25.4) & 0.14 (39.2) \\ In & 0.003 (25.0) & - \\ Ba & 0.5 (2.8) & 0.6 (46.6) \\ Pb & 0.002 (141.4) & 0.002 (141.4) \\ \hline \end{tabular}
\end{table} 
Table 4: Intra-sample variability expressed as the average and relative standard deviations (RSD%) (in brackets) of elemental concentration measured in leachates from samples D1-D2 (second column) and samples E1-E2 (third column).