Mineral processing wastewater includes processing effluent, tailings pond overflow, and mine drainage. Processing effluent is generally transported to the tailings pond along with the tailings slurry, collectively referred to as tailings water, which typically accounts for 60% to 70% of the total discharge of mineral processing wastewater. The volume of mineral processing wastewater is massive, representing approximately 34% to 79% of the entire mine’s total wastewater discharge.
This type of wastewater features a high concentration of suspended solids (SS)—mainly consisting of silt, sand, and tailings powder—which do not easily settle naturally. Furthermore, the wastewater contains a wide variety of hazardous pollutants. If discharged or leaked without proper treatment, it will severely contaminate water sources and soil, endanger aquatic life and vegetation, and silt up rivers and lakes.
Ferrous sulfate ($\text{FeSO}_4$) can be utilized to treat mineral processing wastewater. For cyanide-containing wastewater, chemical oxidation methods—such as the bleaching powder oxidation method—are primarily selected. Alternatively, cyanide removal can also be achieved through the ferrous sulfate-lime method and the lead-zinc ore method.
When applying the lime-ferrous sulfate treatment process, lime milk and acid are first dosed into the water to adjust the pH value to around 7. Subsequently, $\text{FeSO}_4$ and $\text{Cl}_2$ are added to the contact aeration tank. Following blast aeration, the mixture enters the sedimentation tank for further settling. The treated effluent can meet discharge standards for safe release or be recycled, achieving a water reuse rate of up to 85%. The sludge and residue filtered out from the pre-sedimentation and final sedimentation tanks are thoroughly mixed with flocculants. After separation by a decanter centrifuge, the liquid phase flows back into the pre-sedimentation tank, while the solid cake is transported to the tailings storage facility (TSF).
Post time: May-28-2026
