The removal of residual organic flotation reagents from mineral processing wastewater (MPW) can be divided into two steps: the tailings pulp settles in the tailings reservoir, and the effluent from the reservoir is treated in a wastewater treatment station. To simplify the wastewater treatment process, this work explored the fundamental problems of removing residual sodium oleate (NaOl) from tailings wastewater by one step starting from tailings pulp treatment. The removal behavior and mechanism of NaOl from wastewater by metal ions combined with gangue minerals in the tailings pulp were studied. The concentration of NaOl was determined using chemical oxygen demand (COD). Results showed that the newly prepared 100 mg/L NaOl solution formed NaOl colloid after a period of time, and Fe³⁺ and Al³⁺ were more conducive to the COD removal of NaOl colloid than Ca²⁺. Moreover, metal ions and gangue minerals played a synergistic role in enhancing the COD removal of NaOl colloid. Mechanism analysis showed that the unit charge solubility of FeOl₃ or AlOl₃ was much lower than that of CaOl₂, so Fe³⁺ or Al³⁺ was more likely to precipitate with NaOl than Ca²⁺. The addition of Fe³⁺ or Al³⁺ to NaOl colloid reduced the absolute value of the zeta potential of the suspended solids under suitable pH conditions, leading to colloid condensation. When metal ions and gangue minerals coexisted, gangue minerals adsorbed part of NaOl and played the role of coarse particles carrying fine particles to settle. This finding can be used to explain the synergistic effect of metal ions and gangue minerals. The study provides a new idea for the treatment of MPW and has great application prospect.

从选矿废水（MPW）中去除残留的有机浮选试剂可分为两个步骤：尾矿浆沉降在尾矿库中，库中出水在废水处理站进行处理。为简化废水处理工艺，本工作从尾矿浆处理入手，探索一步去除尾矿废水中残留油酸钠（NaOl）的根本问题。研究了尾矿浆中金属离子结合脉石矿物对废水中NaOl的去除行为及机理。使用化学需氧量 (COD) 确定 NaOl 的浓度。结果表明，新配制的100 mg/L NaOl溶液经过一段时间后形成NaOl胶体，Fe ³⁺和Al ^{3+较Ca 2+}更有利于NaOl胶体的COD去除。此外，金属离子和脉石矿物对增强NaOl胶体的COD去除起到协同作用。机理分析表明，FeOl ₃或AlOl ₃的单位电荷溶解度远低于CaOl ₂，因此Fe ³⁺或Al ³⁺比Ca ²⁺更容易与NaOl沉淀。添加Fe ³⁺或Al ³⁺NaOl 胶体在合适的 pH 条件下降低了悬浮物的 zeta 电位的绝对值，导致胶体凝聚。当金属离子与脉石矿物共存时，脉石矿物吸附部分NaOl，起到粗粒携带细粒沉降的作用。这一发现可以用来解释金属离子和脉石矿物的协同作用。该研究为MPW的治疗提供了新的思路，具有广阔的应用前景。