# Study of Oxidative-Reductive Potential Changes in the Enrichment of Oxidized Polymetallic Ores
## 3 Results and Discussion  
The principal technological flowchart of the laboratory experiment is shown in Figure 3.  
Sodium sulfide was used to activate the oxidized minerals [13; 14; 15]. The results of the open laboratory experiments are presented in Table 6. \begin{table}
\begin{tabular}{l c} \hline
**Parameter** & **Content** \\ \hline Sodium and potassium, meq/L & 4.80 \\ \hline Calcium, meq/L & 6.40 \\ \hline Magnesium, meq/L & 3.40 \\ \hline Chloride ion, meq/L & 0.50 \\ \hline Sulfate ion, meq/L & 8.81 \\ \hline Bicarbonate ion, meq/L & 5.20 \\ \hline Nitrate ion, meq/L & 0.09 \\ \hline Total hardness, \({}^{\circ}\)dH & 9.80 \\ \hline Carbonate hardness, \({}^{\circ}\)dH & 5.20 \\ \hline pH, units & 7.50 \\ \hline \end{tabular}
\end{table} 
Table 4: Chemical analysis of the tap water used in flotation tests. \begin{table}
\begin{tabular}{l c c c c c} \hline
**Operation** & **Time (min)** & \multicolumn{4}{c}{**Reagent Consumption (g/l)**} \\ \cline{3-5}  & & **Sodium Bisulfide** & **Thiocarbamate-** & **Sodium Butyl** & **Methyl Isobutyl** \\  & & **Based Collector** & **Xanthine** & **Ketone (MIBK)** \\ \hline Total: & & 0-900 & 5 & 165 & 10 \\ \hline Grinding, \(-\)0.071 mm, 70\% & 10 & - & - & - & - \\ \hline Rougher flotation & 10 & 0-900 & 5 & 120 & 5 \\ \hline Scavenger flotation & 7 & - & - & 45 & 5 \\ \hline \end{tabular}
\end{table} 
Table 5: Conditions of laboratory tests. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Consumption of Na\({}_{2}\)S (g/t) and Redox Potential (mV)**} & \multirow{2}{*}{**Product**} & \multirow{2}{*}{**Yield, \%**} & \multicolumn{2}{c}{**Content, \%**} & \multicolumn{2}{c}{**Recovery, \%**} \\ \cline{4-7}  & & & **Zn** & **Pb** & **Zn** & **Pb** \\ \hline \multicolumn{7}{c}{Test 1} \\ \hline \multirow{7}{*}{0 (100)} & Concentrate-1 & 3.45 & 1.92 & 7.43 & 9.46 & 28.47 \\ \cline{2-7}  & Concentrate-2 & 0.98 & 2.34 & 8.28 & 3.28 & 9.02 \\ \cline{2-7}  & \(\Sigma\) Concentrate & 4.43 & 2.01 & 7.62 & 12.74 & 37.48 \\ \cline{2-7}  & Tailings & 95.57 & 0.64 & 0.59 & 87.26 & 62.52 \\ \cline{2-7}  & Total & 100.0 & 0.70 & 0.90 & 100.0 & 100.0 \\ \hline \multicolumn{7}{c}{Test 2} \\ \hline \multirow{7}{*}{500 (\(-120\))} & Concentrate-1 & 3.76 & 1.74 & 9.48 & 9.34 & 39.60 \\ \cline{2-7}  & Concentrate-2 & 1.09 & 2.08 & 5.81 & 3.24 & 7.03 \\ \cline{2-7}  & \(\Sigma\) Concentrate & 4.85 & 1.82 & 8.65 & 12.58 & 46.63 \\ \cline{2-7}  & Tailings & 95.15 & 0.64 & 0.51 & 87.42 & 53.37 \\ \cline{2-7}  & Total & 100.0 & 0.70 & 0.90 & 100.0 & 100.0 \\ \hline \multicolumn{7}{c}{Test 3} \\ \hline \multirow{7}{*}{600 (\(-160\))} & Concentrate-1 & 4.02 & 1.63 & 9.13 & 9.36 & 40.76 \\ \cline{2-7}  & Concentrate-2 & 1.19 & 1.95 & 5.21 & 3.31 & 6.89 \\ \cline{2-7}  & \(\Sigma\) Concentrate & 5.21 & 1.70 & 8.23 & 12.67 & 47.65 \\ \cline{2-7}  & Tailings & 94.79 & 0.64 & 0.50 & 87.33 & 52.35 \\ \cline{2-7}  & Total & 100.0 & 0.70 & 0.90 & 100.0 & 100.0 \\ \hline \multicolumn{7}{c}{Test 4} \\ \hline \multirow{7}{*}{700 (\(-200\))} & Concentrate-1 & 4.12 & 1.39 & 9.18 & 8.18 & 42.03 \\ \cline{2-7}  & Concentrate-2 & 1.28 & 1.87 & 5.65 & 3.42 & 8.03 \\ \cline{2-7}  & \(\Sigma\) Concentrate & 5.40 & 1.50 & 8.34 & 11.60 & 50.07 \\ \cline{2-7}  & Tailings & 94.60 & 0.65 & 0.48 & 88.40 & 49.93 \\ \cline{2-7}  & Total & 100.0 & 0.70 & 0.90 & 100.0 & 100.0 \\ \hline \end{tabular}
\end{table} 
Table 6: Scheme of open experiments on test trials of the effect of sodium sulfide on the flotation process. Figure 3: The principal technological flowchart of the laboratory experiment. The results from Table 1 show that without prior sulfidization, the flotation of lead is low, with a recovery of 37.48%. These results are comparable to data from the literature, which indicate the necessity of performing sulfidization. As the dosage of Na\({}_{2}\)S increased from 0 to 700 g/t (Tests 1 through 4), the recovery of lead steadily rose. The highest lead recovery was observed in Test 4 with 700 g/t Na\({}_{2}\)S: about 50.07% of the lead was recovered.