Investigation of Mineral-Processing Wastewater Recycling Processes: A Pilot Study

Mineral processing requires large amounts of water, but, often in the remote locations of many mines, sufficient fresh water frequently cannot be supplied. Therefore, recycling of water is important in mineral processing and enhancing the efficiency of the liquid-solid separation and dewatering steps in mineral processing wastewater treatment is critical. The objectives of the study were to evaluate the effect of anionic flocculant dosage and sludge recycling (SR) on solid removal and sludge dewaterability. Different combinations of the flocculant dosage with and without SR were applied in a mineral-processing wastewater treatment pilot plant. Increasing the amount of flocculant dose of 1.1% v/v (flocculant solution to wastewater) did not significantly decrease the turbidity of the treated water, while the combination of a flocculant with SR increased the zeta potential. Increasing flocculant dose adversely affected dewaterability, although the dewaterability of the 0.6% v/v flocculant-treated sludge significantly increased after aging of the sludge. Sludge recycling was effective for increasing the dewaterability, and a flocculant dose of 1.1% v/v with SR led to formation of large flocs that were stable during aging and sonication.