# Use of Mineral Waste for the Production of Artificial Aggregates
## 4 Non-Ferrous Metallurgical Waste
### Chemical and Phase Composition  
The predominant components in the chemical composition of metallurgical slags formed directly in the process of obtaining Zn and Pb include the following: FeO\({}_{\text{total}}\), SiO\({}_{2}\), Al\({}_{2}\)O\({}_{3}\), CaO, MgO, ZnO, and PbO [35; 36; 37; 38; 39; 40]. Slags are characterized by a wide variation in the content of the main constituents, which fall within a wide range: FeO\({}_{\text{total}}\) between 0.88 wt.% and 59.6 wt.%, SiO\({}_{2}\) between 2.04 wt.% and 57.1 wt.%, CaO between 0.18 wt.% and 32.23 wt.%, MgO between 0.61 wt.% and 15.9 wt.%, ZnO between 0.03 wt.% and 47.3 wt.%, PbO between 0.002 wt.% and 6.4 wt.%, and Cu below 0.002 wt.% (Table 5). Refining slags (Figure 4) show a different chemical composition from that of slags from the shaft process of Zn-Pb metallurgy, as they are dominated by ZnO (average content 12.2 wt.%), PbO (average content 17.5 wt.%), CuO (average content 11.5% wt.%), and SO\({}_{3}\) (average content 13.6 wt.%), while in slags from the shaft process, their average content is several times lower. As in the case of slags from the shaft process, their composition also varies considerably (Table 6). In addition to the main components represented in oxide form, Zn-Pb metallurgical slags also contain numerous minor constituents, including As, Ba, Cd, Co, Cr, Cu, Ni, Sb, Sn, and V, the concentrations of which vary markedly. The elements that prevail in the chemical composition of slag samples from Zn-Pb metallurgy and whose maximum concentration is higher than 1 wt.% include the following: As, Ba, Cd. The content of other minor components, i.e., Co, Cr, Ni, Sb, Sn, and V, does not exceed 0.5 wt.%. \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline \multirow{2}{*}{**Component**} & \multicolumn{2}{c}{**Zn-Pb Slags**} & \multicolumn{4}{c}{**Pb Refining Slags**} \\ \cline{2-7}  & **Min** & **Max** & **Average** & **Min** & **Max** & **Average** \\ \hline Al\({}_{2}\)O\({}_{3}\) & 0.90 & 21.9 & 8.3 & 0.57 & 7.8 & 2.8 \\ CaO & 0.18 & 32.2 & 17.3 & 0.14 & 5.65 & 2.8 \\ FeO\({}_{\text{Total}}\) & 0.88 & 59.6 & 16.7 & 8.3 & 31.1 & 20.0 \\ K\({}_{2}\)O & 0.02 & 3.91 & 0.60 & 0.04 & 0.27 & 0.15 \\ CuO & - & - & - & 0.98 & 20.93 & 11.5 \\ MgO & 0.61 & 15.9 & 5.4 & 0.10 & 0.81 & 1.1 \\ PbO & 0.0002 & 6.4 & 0.93 & 0.72 & 44.6 & 17.8 \\ ZnO & 0.03 & 47.2 & 4.93 & 6.6 & 18.07 & 12.2 \\ MnO & 0.01 & 3.0 & 0.5 & 0.02 & 0.55 & 0.21 \\ SO\({}_{3}\) & 0.05 & 14.9 & 2.99 & 5.83 & 23.1 & 13.6 \\ SiO\({}_{2}\) & 2.04 & 57.1 & 28.6 & 2.45 & 35.5 & 11.1 \\ TiO\({}_{2}\) & 0.07 & 1.14 & 0.4 & 0.04 & 0.34 & 0.16 \\ \hline Element & Min & Max & Average \({}^{*}\) & Min & Max & Average \({}^{**}\) \\ \hline As & 1 & 10,710 & 1181 & 147 & 15,558 & 8843 \\ Ba & 76 & 17,914 & 1126 & 336 & 778 & 508 \\ Cd & 0.38 & 575 & 31.2 & 85 & 19,757 & 5595 \\ Co & 8.5 & 242 & 35.7 & 0.01 & 452 & 232 \\ Cr & 4 & 700 & 155 & 132 & 708 & 435 \\ Ni & 13 & 240 & 59.7 & 76 & 447 & 311 \\ Cu & 16 & 7400 & 802 & - & - & - \\ P & 43.57 & 26,400 & 5138 & - & - & - \\ Sb & 0.16 & 245 & 42.6 & 81 & 9869 & 472 \\ Sn & 0.1 & 500 & 23.4 & 0.01 & 617 & 323 \\ V & 6 & 9980 & 2294 & - & - & - \\ \hline \hline \end{tabular} \({}^{*}\) Arithmetic average values according to [44]: \({}^{**}\) arithmetic average values of 64 samples according to [41].  
\end{table} 
Table 5: Summary of major chemical composition (in wt.%) and minor elements concentration (in mg kg\({}^{-1}\)) of Zn-Pb metallurgical slags and Pb refining slags [38; 40; 41; 42; 43]. The variability in the chemical composition of metallurgical slags taken from different landfill layers is the result of a number of factors; some of them are the diversity of feedstock for the lead refining process, the conditions of the industrial process itself, and weathering processes occurring in the landfill body (in the case of landfilled slags).