Mining wastewater is generated during mining and mineral processing, with primary pollutants including suspended solids, heavy metals, and salts. Physical-chemical methods are commonly used for treatment. For example, in gold ore beneficiation processes: cyanide leaching + zinc powder displacement/activated carbon adsorption (see detailed cyanide gold extraction flowchart). The cyanide leaching process uses cyanide compounds such as sodium cyanide as solvents for dissolving gold and adds lime to adjust the pH (to prevent low pH causing cyanide gas release). This process generates large amounts of alkaline wastewater containing high concentrations of cyanide ions (CN? and SCN?, with cyanide concentrations ranging from 100-500 mg/L) and various heavy metals (Cu2?, Pb2?, Zn2?, etc.), as well as copper-cyanide complexes. Although some copper-cyanide complexes are dissolved and precipitated by zinc powder displacement, significant residues remain, sometimes as high as 2000 mg/L, leading to reduced leaching efficiency and increased sodium cyanide consumption. Therefore, removing copper-cyanide complexes and other adverse metal ions while retaining CN? enables the cyclic utilization of lean solutions, reducing sodium cyanide and fresh water consumption, and meeting requirements for wastewater treatment and reuse/zero discharge. Typically, a two-step precipitation method is used to remove impurities from the lean solution after zinc powder displacement, achieving purification and reuse of the lean solution. Specifically: ① Add sulfuric acid to acidify the lean solution to pH ≤ 2 (under closed conditions), forming copper thiocyanate and copper-cyanide complex precipitates, removing high concentrations of thiocyanate (SCN?) and heavy metals like copper (Cu2? removal rate >95%). This stage typically uses a thickener to separate copper mud from water. ② Add lime to form CaSO? precipitate (pH 10-11), removing sulfate ions (SO?2?). This stage's thickener can be upgraded or modified to an M+FLO magnetic sand settling tank for efficient and deep removal of calcium sulfate suspensions.

M⁺FLO Magnetic Flocculation Settling Tank (as shown in the flowchart below) can ｒｅｐｌａｃｅ or upgrade the traditional clarification tanks for precious liquid treatment, efficiently and effectively removing suspended solids such as mine mud, thereby enhancing the purity of the precious liquid. Before undergoing zinc powder displacement for deoxygenation, the precious liquid must first pass through a flocculation clarification tank to remove mine mud and purify the liquid.

M⁺FLO-HFO Strong Adsorption Magnetic Flocculation Sedimentation Clarification System, combined with the addition of chemical agents such as Ca(OH)?/NaOH and TMT15, can efficiently and deeply remove suspended solids, arsenic, fluoride, cyanide, heavy metals, and other pollutants from mining and mineral processing wastewater.

The M⁺FLO-LDH Magnetic Flocculation + Chemical Desalination and Softening Water Treatment System, combined with the addition of chemical agents such as Ca (OH)?, LDH, and CO?, can effectively remove sulfate salts, chloride salts, silicate salts, total salts, and calcium and magnesium hardness. The resulting LDH calcium composite salts and other byproducts are non-polluting inorganic calcium alum minerals that can be used as raw materials for metallurgy or cement production, achieving resource recovery and utilization. This system is suitable for efficient and economical desalination and softening treatment of industrial and mining wastewater (TDS~3000 mg/L). Its performance and advantages include: total salt removal efficiency ~70%, final effluent TDS <1000 mg/L, Cl? <150 mg/L, SO?2? <150 mg/L, SiO? <5.0 mg/L, hardness <50 mg/L, and turbidity <1.0 NTU. The treatment cost per ton of water is approximately 1.0-3.0 CNY (mainly related to the amount of removed anions). Compared to pretreatment (de-turbidity/softening) + reverse osmosis desalination + evaporation crystallization technology, it has obvious advantages such as simple process, low investment, low operating costs, and intelligent automatic control. However, its desalination depth is less than that of reverse osmosis (RO/DTRO).

Case Study of M⁺FLO Magnetic Flocculation Sedimentation Tank for Gold Mine Wastewater Treatment:

At the Laizhou Xincheng Gold Mine of Shandong Gold Group, the daily production of mine water is 20,000 tons (raw water turbidity <291 NTU, F? <2.70 mg/L). The treated effluent must meet the discharge standards for mining wastewater (turbidity <10 NTU, F? <1.0 mg/L). The treatment process is: mine water → pretreatment equalization tank → M+FLO magnetic flocculation sedimentation tank → clear water tank. The M+FLO magnetic sand sedimentation tank system was put into operation in July 2020, operates normally, and achieves stable effluent quality (effluent turbidity <1.0 NTU, F? <1.0 mg/L).