# Separation of Iron Oxide from Harbor Waste Using Selective Flocculation
## 3 Results
### Selective Flocculation Tests
#### 3.4.1 Initial Selective Flocculation Tests Under Different Conditions  
In this chapter, the influences of pH, presence/absence of flocculant (PAM), and presence/absence of flocculant (PAM) and dispersant (SHMP) on the selectivity were tested. All flocculation tests were performed on starting raw material--sample K. Flocculation behavior was tested by monitoring the weight distribution and the content grade of basic chemical composition between the settling and floating parts. Each test was repeated five times in similar conditions, and the average was calculated. The results are presented in Table 6 and Figure 9.  
Initial tests have shown that deposition at different pH values without the presence of reagents takes place slowly. At pH values of four and six, a clear zone above the precipitated sample is visible, while at pH 10.5 values, turbidity and poor visibility of the separation zone of the overflow and sediment occur. With the addition of flocculant, A 100, at pH 10.5, a significant difference in mass distribution between settling and floating parts is visible. However, there is no difference in the content of the basic components. This indicates that the flocculant acts but non-selectively. The test results with dispersants and flocculants showed that precipitation occurs at pH values of four and six and that there is no selectivity. Therefore, further tests were focused on pH 10.5, taking into account the mass distribution and the content of all tested components in the settling and floating parts. Due to the poor visibility of the separation zone between the overflow and sediment, the deposition time was extended to 5 min. The best selectivity was achieved under these conditions, considering that the aim of this research was to increase the content of iron and reduce the content of impurities in the settling part and to reduce the content of iron and increase the content of other components in the floating part. Figure 9: Selective flocculation at different pH (4, 6 and 10.5, from left to right). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{ \begin{tabular}{c} **Test** \\ **No.** \\ \end{tabular}  } & **Attempt** & \multirow{2}{*}{**pH**} & \multirow{2}{*}{**Floc. **} & \multirow{2}{*}{**Disp. **} & \multicolumn{4}{c}{**Settified Material**} & \multicolumn{4}{c}{**Floaded Material**} \\ \cline{4-14}  & & & & & **Settified Weight** & **Fe (\%)** & **SiO (\%)** & **Al\({}_{2}\)O3 (\%)** & **Ca (\%)** & **Fload Weight (\%)** & **Fe (\%)** & **SiO (\%)** & **Al\({}_{2}\)O3 (\%)** & **Ca (\%)** \\ \hline \multirow{4}{*}{1} & 1 & & & 67.40 & 34.43 & 7.23 & 4.12 & 3.17 & 32.60 & 33.29 & 6.93 & 4.40 & 3.75 \\ \cline{2-14}  & 2 & & & 63.77 & 33.57 & 6.91 & 3.83 & 3.60 & 36.23 & 37.37 & 7.87 & 4.65 & 3.54 \\ \cline{2-14}  & 3 & & & 65.02 & 38.85 & 6.93 & 4.07 & 3.44 & 34.98 & 34.95 & 7.64 & 4.30 & 3.57 \\ \cline{2-14}  & 4 & & & 67.75 & 32.83 & 6.80 & 4.22 & 3.49 & 32.25 & 35.36 & 8.01 & 3.96 & 3.23 \\ \cline{2-14}  & 5 & & & 65.71 & 33.86 & 6.38 & 3.75 & 3.25 & 34.29 & 35.57 & 7.63 & 4.57 & 3.11 \\ \cline{2-14}  & Avg. & & & & 65.93 & 34.71 & 6.85 & 4.00 & 3.39 & 34.07 & 35.31 & 7.61 & 4.38 & 3.44 \\ \cline{2-14}  & 1 & & & & 51.25 & 35.73 & 6.81 & 3.89 & 3.32 & 48.75 & 35.79 & 7.97 & 4.79 & 3.17 \\ \cline{2-14}  & 2 & & & & 55.39 & 35.30 & 6.55 & 4.02 & 3.28 & 44.61 & 35.80 & 8.01 & 4.88 & 3.39 \\ \cline{2-14}  & 3 & & & & 50.07 & 32.81 & 7.48 & 4.28 & 3.75 & 49.93 & 32.78 & 7.61 & 4.67 & 3.17 \\ \cline{2-14}  & 4 & & & & 49.28 & 33.35 & 6.71 & 4.20 & 3.28 & 50.72 & 34.73 & 7.85 & 4.15 & 3.11 \\ \cline{2-14}  & 5 & & & & 49.93 & 30.99 & 7.76 & 4.62 & 3.53 & 50.07 & 38.39 & 7.98 & 4.59 & 2.94 \\ \cline{2-14}  & Avg.