## 3 Results and Discussion
### Properties of Sintered Aggregates
#### 3.2.1 Loss on Ignition and Water Absorption Rate of the Sintered Aggregates  
The loss on ignition of the sintered aggregate is plotted in Figure 11. It can be clearly observed from Figure 11 that--at the same sintering temperature--the more textile sludge that was added, the greater the loss on ignition, which was between 9.74% and 21.19%. Among them, regardless of the type of textile sludge, the loss on ignition was the largest when adding 22.5% of textile sludge. This means that there were many organic matter components in the textile sludge. Therefore, the more textile sludge that was added, the greater the loss on ignition.  
Further, the water absorption rate of the sintered aggregate is shown in Figure 12. It can be seen from Figure 12 that when the sintering temperature increased, the water absorption rate of the aggregate that used only WPS as the material source decreased from 10.91% to 5.07%. Regarding the rate of A1, A2, and A3, it ranged from 9.18% to 16.21%; B1, B2, and B3 ranged from 14.29% to 20.56%; and C1, C2, and C3 ranged from 13.69% and 22.02%. The results show that after water purification sludge was blended with textile sludge, the water absorption rate of the sintered aggregates increased. In particular, when the water purification sludge was mixed with the textile sludge from Sample B and Sample C, the water absorption rate of the sintered aggregates increased significantly.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Code**} & \multicolumn{2}{c}{**Preheating Stage**} & \multicolumn{2}{c}{**Sintering Stage**} & \multirow{2}{*}{**Loss on**} & \multicolumn{2}{c}{**Aggregate Property**} \\ \cline{2-2} \cline{6-7}  & **Preheating** & **Preheating** & **Sintering** & **Sintering** & **Ignition (\%)** & **24 h Water** & **Particle** \\  & **Tem.** (°C) & **Time (min)** & **Tem.** (°C) & **Time (min)** & **Absorption Rate (\%)** & **Density (g/cm\({}^{3}\))** \\ \hline \multirow{3}{*}{B2} & \multirow{3}{*}{500} & \multirow{3}{*}{5} & 1150 & & 15.28 & 16.99 & 1.05 \\  & & & 1175 & 12.5 & 15.33 & 18.10 & 0.96 \\  & & & 1200 & & 14.84 & 17.67 & 0.73 \\ \hline \multirow{3}{*}{B3} & \multirow{3}{*}{500} & \multirow{3}{*}{5} & 1150 & & 18.51 & 18.43 & 1.23 \\  & & & 1175 & 12.5 & 18.59 & 20.56 & 1.02 \\  & & & 1200 & & 18.67 & 17.17 & 0.91 \\ \hline \multirow{3}{*}{C1} & \multirow{3}{*}{500} & \multirow{3}{*}{5} & 1150 & & 9.88 & 13.69 & 1.07 \\  & & & 1175 & 12.5 & 9.87 & 14.00 & 0.85 \\  & & & 1200 & & 9.74 & 17.54 & 0.69 \\ \hline \multirow{3}{*}{C2} & \multirow{3}{*}{500} & \multirow{3}{*}{5} & 1150 & & 14.86 & 17.45 & 1.19 \\  & & & 1175 & 12.5 & 14.75 & 16.99 & 1.04 \\  & & & 1200 & & 15.00 & 16.02 & 0.82 \\ \hline \multirow{3}{*}{C3} & \multirow{3}{*}{500} & \multirow{3}{*}{5} & 1150 & & 19.12 & 22.02 & 1.10 \\  & & & 1175 & 12.5 & 19.15 & 18.72 & 0.99 \\ \cline{1-1}  & & & 1200 & & 19.47 & 14.22 & 0.90 \\ \hline \hline \end{tabular}
\end{table}
Table 7: _Cont._  
Figure 11: Relationship between the loss on ignition and the sintering temperature for water purification sludge blended with textile sludge: (**a**) Sample A; (**b**) Sample B; and (**c**) Sample C.