## 3 Results and Discussion
### Results of the Characterization of Raw and Sintered Samples
#### 3.2.2 Results of the XRD Analysis of the Raw and Sintered Samples  
For a determination of the crystal-phase composition of all the GC samples in raw form and after sintering at 700 \({}^{\circ}\)C for 7 h, XRD analysis was carried out, and the obtained diffractograms are displayed in Figure 6.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Content of Oxides (wt, \%) in Waste Sludge**} \\ \hline
**Component** & **Al2O3** & **SiO2** & **Fe2O3** & **Na2O** & **K2O** & **CaO** & **MgO** & **SO3** & **P2O5** \\ \hline LP sludge & 2.68 & 1.971 & 4.35 & 3.56 & 2.609 & 0.167 & 0.133 & 0.095 & 2.255 \\ PE sludge & 16.67 & 10.78 & 11.01 & 19.29 & 3.792 & 3.455 & 0.697 & 0.856 & 8.57 \\ LP+PE sludge (1:1) & 9.675 & 6.3755 & 7.68 & 11.425 & 3.201 & 1.811 & 0.415 & 0.475 & 5.413 \\ \hline \end{tabular}
\end{table}
Table 2: Constituents in the composition of waste sludge—oxide content.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{5}{c}{**Concentration, mg/kg, in Adhesive and Sealant Sample Composition**} \\ \hline
**Parameter** & **GC5** & **GC10** & **GC15** & **GC20** & **Ref. Values** \\ \hline Hg & \textless{}0.15 & \textless{}0.15 & \textless{}0.15 & \textless{}0.15 & 0.2*/2** ** \\ Sb & 0.7038 & 1.4076 & 2.1114 & 2.8152 & 0.7*/5** \\ Se & \textless{}0.022 & \textless{}0.044 & \textless{}0.066 & \textless{}0.088 & 0.5*/7** \\ Cu & 16.8746 & 33.7492 & 50.6238 & 67.4984 & 50*/100** \\ Zn & 1.7319 & 3.4638 & 5.1957 & 6.9276 & 50*/200** \\ Ni & 1.5811 & 3.1622 & 4.7433 & 6.3244 & 10*/40** \\ Cd & 0.0693 & 0.1386 & 0.2079 & 0.2772 & 1*/5** \\ Pb & 0.383 & 0.7660 & 1.149 & 1.532 & 10*/50** \\ As & \textless{}0.0245 & \textless{}0.0490 & \textless{}0.0735 & \textless{}0.098 & 2*/25** \\ Cr & 0.2445 & 0.4890 & 0.7335 & 0.978 & 10*/70** \\ Mn & 44.4582 & 88.9164 & 133.3746 & 177.8328 & - \\ Tl & \textless{}0.0245 & \textless{}0.0490 & \textless{}0.0735 & \textless{}0.098 & - \\ Fe & 260.8 & 521.6000 & 782.4 & 1043.2 & - \\ Co & 19.0343 & 38.0686 & 57.1029 & 76.1372 & - \\ \hline \end{tabular}
\end{table}
Table 3: Analysis results of heavy metal content in adhesive and sealant samples containing waste.  
The mineralogical composition of the samples was determined by identifying the crystal phases of the following clay minerals: quartz, as the most abundant; then albite; minerals from the group of zeolites; and wollastonite. It was observed that the identified mineral phases had high structural order, which is indicated by sharp and high-intensity peaks. The slightly higher background present in the angular range of 5-30\({}^{\circ}\) 20 of the raw samples' diffractograms most likely represents a slightly higher content of organic and amorphous phase in these samples. Moreover, narrow, high-intensity, and clearly defined peaks of quartz and zeolite minerals in the raw samples indicate a good structural arrangement of these phases, while wollastonite's peaks have some lower intensities, which most likely indicate the content of this phase is a little lower. The structural arrangements of the identified minerals remained unchanged during thermal treatment at 700 \({}^{\circ}\)C; also, new phases were not identified. However, considering the obvious alignment of the baseline in the diagrams, it can be said that thermal treatment led to the disappearance of the organic  
Figure 6: XRD diffractograms of all GC samples in raw form and after sintering at 700 \({}^{\circ}\)C: GC\({}_{0}\), GC\({}_{5}\), GC\({}_{10}\), GC\({}_{15}\), and GC\({}_{20}\), respectively.  
phase since a better structural arrangement in the angular range of 5-30\({}^{\circ}\) 20 occurred in the sintered samples.