# The Use of Construction Waste to Remediate a Thermally Active Spoil Heap
## 3 Results and Discussion
### Chemical Composition of Construction and Demolition Waste  
In a circular economy, it is important to identify all possible ways of reusing resources, and construction and demolition waste is a rich source of a whole range of basic cations. The chemical composition of the used construction waste is shown in Table 5.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**\%** & **Burnt Tailings** & **Tailings** & **\%** & **Burnt Tailings** & **Tailings** \\ \hline
**Fe** & 14.93 & 24.96 & **Te** & \textless{}0.00030 & \textless{}0.00030 \\
**Ga** & 0.0091 & 0.0094 & **Th** & 0.0068 & 0.0082 \\
**Ge** & 0.0005 & 0.0002 & **Ti** & 1.57 & 1.30 \\
**Hf** & 0.0021 & 0.0021 & **Ti** & 0.00042 & 0.0004 \\
**Hg** & \textless{}0.00010 & 0.0061 & **U** & 0.0018 & 0.0023 \\
**I** & 0.0005 & 0.059 & **V** & 0.04 & 0.05 \\
**K** & 7.93 & 5.53 & **W** & 0.0051 & 0.0019 \\
**La** & 0.0140 & 0.012 & **Y** & 0.0110 & 0.0098 \\
**Mg** & 1.98 & 0.20 & **Zn** & 0.05 & 0.05 \\
**Mn** & 0.23 & 0.09 & **Zr** & 0.0898 & 0.0715 \\ \hline \hline \end{tabular}
\end{table}
Table 4: _Cont._  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**\%** & **CDW** & **\%** & **CDW** \\ \hline
**Na** & \textless{}0.01 & **Cu** & 0.01 \\
**Te** & \textless{}0.0003 & **La** & 0.022 \\
**Ag** & 0.002 & **Cl** & \textless{}0.0002 \\
**Bi** & \textless{}0.0001 & **Ta** & 0.02 \\
**Hg** & \textless{}0.0001 & **Pb** & 0.008 \\
**Se** & \textless{}0.00005 & **Y** & 0.008 \\
**Si** & 45 & **Cs** & 0.01 \\
**Al** & 8.5 & **Co** & 0.003 \\
**Fe** & 8.0 & **Ga** & 0.005 \\
**K** & 3.4 & **Th** & 0.003 \\
**Ca** & 27 & **Nb** & 0.006 \\
**Mg** & 0.82 & **Pr** & 0.0004 \\
**Ti** & 1.09 & **W** & 0.0002 \\
**S** & 0.53 & **Sn** & \textless{}0.0003 \\
**Ba** & 0.17 & **Hf** & 0.006 \\
**Mn** & 0.19 & **Sb** & \textless{}0.0003 \\
**P** & 0.14 & **U** & 0.0002 \\
**Zr** & 0.29 & **Cd** & \textless{}0.0002 \\
**Cr** & 0.10 & **As** & 0.002 \\
**Rb** & 0.02 & **Mo** & 0.001 \\
**Zn** & 0.27 & **Br** & 0.0004 \\
**V** & 0.03 & **Ge** & 0.0002 \\
**Sr** & 0.05 & **I** & 0.0002 \\
**Ce** & 0.02 & **TI** & 0.0002 \\ Nd & 0.02 & **Cu** & 0.01 \\
**Ni** & 0.02 & **La** & 0.02 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Chemical composition of construction and demolition waste.  
The chemical composition of construction and demolition waste shows that the predominant elements are Si (45%) and Ca (27%). Since the content of heavy metals is also negligible and their representation does not exceed the volume of other industrial emissions from an ecological point of view, it therefore does not represent a serious environmental burden. Construction and demolition waste can therefore be used to prepare a suitable mixed material that could be used for the remediation of the immediate surroundings of thermally active spoil heaps. It can be used as a base layer on which soil would then be spread. In this way, a suitable base for remediation could be created. At the same time, a problematic spoil heap having a negative impact on its surroundings and the health of local residents would be removed as well.