The efficient removal and stabilization of arsenic in copper smelting waste acid is a difficult problem for the green development of the industry. Although the existing lime-iron salt method can remove arsenic, it produces a large amount of arsenic-containing waste residue, which has the risk of secondary pollution. In order to achieve treating waste with waste, the treatment of arsenic in waste acid by copper tailings was studied. Through the synergistic oxidation-precipitation mechanism of hydrogen peroxide, the effects of initial pH, solid mass to liquid volume ratio, reaction temperature, reaction time and hydrogen peroxide dosage on arsenic removal and arsenic stability were systematically investigated. The results show that under the optimal conditions of initial pH= 0.65, solid mass to liquid volume ratio of 1 g/8 mL, reaction temperature of 60 ℃, reaction time of 10 h, and 30% hydrogen peroxide dosage of 2.0 mL/100 mL, the removal rate of arsenic in waste acid reaches more than 97%, and the arsenic leaching concentration of arsenic-containing tailings after treatment reaches the standard. The method can realize the efficient removal and solidification of arsenic in waste acid, which provides a new technical support for the resource utilization of copper tailings and the treatment process of waste acid.

The iron content in flotation tailings of copper smelting slag is high, which has further comprehensive recycling value. Based on the difference of decomposition performance of fayalite and magnetite minerals in copper tailings in acidic solution, the recovery of iron from copper smelting tailings by sulfuric acid leaching－magnetic separation process was studied. The effects of various factors on iron recovery were investigated, and the optimal leaching and magnetic separation conditions were determined. The results show that under the optimized acid leaching conditions of sulfuric acid concentration of 0.2 mol/L, liquid volume to solid mass ratio of 4∶1, leaching temperature of 40 ℃ and leaching time of 60 min, the total iron mass fraction in the leaching residue is 52.57%, and the iron recovery rate is 95.17%. The optimum magnetic separation conditions are as follows: grinding particle size 28 μm accounts for 90%, magnetic separation field strength 140 kA/m. Under the conditions, the total iron grade of iron concentrate is 59.25%, and the iron recovery rate is 85.70%. The process has good economic feasibility and can provide reference for the resource utilization of iron in flotation tailings of copper smelting slag.

In order to solve the problem of fluorine-containing water pollution, lanthanum chloride precipitation method was used to remove fluorine from it. Through in-depth analysis of the chemical characteristics and thermodynamic reaction mechanism of the solution, the interaction between La³⁺ and F^- in aqueous solution was revealed. The effects of initial pH of the solution, the amount of lanthanum chloride, reaction temperature and time on the removal of fluoride were investigated by single factor test, and the optimized process parameters were determined. The results show that for the fluorine-containing simulated solution with fluorine ion mass concentration of 0.1－1.0 g/L, under the conditions of initial solution pH of 3.0, lanthanum chloride dosage of 1.3 times of the theoretical amount, reaction temperature of 50 ℃ and reaction time of 10 min, the fluorine removal rate is more than 95%, and the residual fluorine ion mass concentration in the liquid after fluorine removal is less than 30 mg/L, which meets the fluoride emission limit specified in the national standard. The method has good process applicability in a wide range of fluorine concentration and has certain application value.

Aiming at the problems of high chemical inertness of high-rank anthracite, high energy consumption and high pollution of traditional activation process, a two-step process of potassium ferrate activation－thiourea gas phase doping was used to prepare high-performance nitrogen and sulfur co-doped porous carbon. The effects of activation temperature, mass ratio of potassium ferrate to coal and activation time on the preparation of porous carbon CDC were investigated by Box-Behnken method. Then, nitrogen and sulfur were doped into thiourea gas phase to obtain NS-3-850. The microstructure and surface chemical properties were characterized by SEM-EDS, XRD, Raman and XPS. The electrochemical properties were tested by CV and GCD methods. The results show that the method effectively constructs a hierarchical pore structure dominated by micropores and coordinated by mesopores, and successfully introduces nitrogen-and sulfur-containing functional groups into the carbon skeleton. The obtained nitrogen and sulfur co-doped porous carbon has a high specific surface area (1 393 m²/g) and an optimized mesoporous ratio (33.69%). The pore structure is suitable for ion diffusion and the surface functional groups are improved. NS-3-850 exhibits good energy storage performance in 6 mol/L KOH electrolyte, and the specific capacitance is 220 F/g at current density of 0.5 A/g. The preparation process provides a feasible technical path for the directional conversion and functionalization of inert coal by wet chemical means.

A self-synthesized novel composite alkaline slow-release material was studied for the treatment of uranium mine acid mine drainage (AMD) containing high concentrations of . Static tests were first conducted to screen for an optimal composite alkali-releasing material. Subsequently, static condition tests and dynamic column experiments were carried out to evaluate the alkali-release performance, physical stability, and the removal efficiency of U(Ⅵ) and Mn from simulated AMD. The results show that for an acidic solution with pH 2.6 and mass concentration of 2.7 g/L, the optimal composite alkali-releasing material exhibits good resistance to pulverization and sustained alkali-release performance. In the dynamic column experiment, when the material contacted the solution for 40 minutes, the effluent pH can be stably raised to 8－9. With initial mass concentrations of U and Mn at 1 mg/L and 2.9 mg/L, respectively, the removal rates of U and Mn are 69.8% and 67.2%, respectively. The material demonstrates long-term resistance to pulverization under the erosion of high-concentration acid, making it suitable for use as a slow-release alkali source in Permeable reactive barrier (PRB) technology.

To enhance comprehensively recovery efficiency of zirconium resources from polymetallic deposits, and support the development of clean energy, a systematic analysis was conducted on the raw ore, zircon concentrate, tailings, and hydrometallurgical products at different stages from an alkaline granite porphyry-type polymetallic deposit in Inner Mongolia. Multi-techniques, including optical microscopy, SEM-EDS, XRD, and AMICS was used to systematically reveal the occurrence forms and liberation characteristics of zirconium throughout the entire beneficiation and metallurgical process. The research results show that zirconium mainly occurs as independent zircon in the raw ore and processing products, with minor amounts occurring in the form of isomorphic, substituting for Th⁴⁺ and U⁴⁺ ions and dispersing in carrier minerals such as thorite, pyrochlore, and monazite. Zircon is progressively enriched and liberated during beneficiation, although fine-grained zircon particles are still lost in gravity tailings due to encapsulation or intergrowth. During hydrometallurgical treatment, zircon is converted into Zr compounds via alkali fusion, but some particles remain incompletely reacted or are encapsulated by newly formed siliceous materials, leading to residual zirconium in the acid-leaching residue, either as zircon or zirconium-bearing siliceous compounds. Based on these findings, an improved process of "stage grinding-stage seperation optimization dissolution-enhanced alkali fusion pretreatment" is proposed, providing mineralogical support for optimizing the ore beneficiation and metallurgical process.

Lithium-ion batteries (LIBs) are promising for application in new energy and energy storage fields owing to their high energy efficiency, high power density, long cycle life, and low self-discharge rate. However, the limited lifespan of lithium batteries leads to substantial generation of waste batteries. Metals such as lithium and cobalt within their cathode materials belong to strategic resources. Recycling waste lithium batteries not only alleviates pressure on primary resource exploitation and reduces environmental pollution but also enables closed-loop recycling of metallic resources. The composition and the recycling process of lithium batteries are introduced. The research on metals recovery from lithium battery cathode materials through inorganic acid leaching, organic acid leaching, bioleaching, and deep eutectic solvent leaching is summarized. Technical guidance is provided for the recovery of valuable metals from waste lithium batteries.

As one of the globally strategic critical metals, rhenium often exists in copper ores in an associated form. Copper smelting waste acid, an important carrier of rhenium resources, exhibits complex characteristics including high acidity, high impurity content, and low rhenium concentration. The characteristics pose formidable challenges to the rhenium recovery process. The key technologies for rhenium recovery from waste acid, with a particular emphasis on the progress of advanced purification technologies targeting the leaching solution are systematically summarized. The working principles, process optimization approaches, and industrial application effectiveness of solvent extraction and ion exchange methods are analyzed in depth. Moreover, the differentiated technical routes for leaching solution purification employed by major copper smelting enterprises worldwide are compared. Based on this, the key technical bottlenecks and potential breakthroughs for future development in this field are explored from multiple perspectives, including innovation of separation materials, process intensification, process integration, and secondary pollution control. The aim is to offer in-depth theoretical references and practical guidelines for the efficient, environmentally friendly, and high-value recovery of rhenium resources from waste acid.

Fly ash, as a large-scale industrial solid waste rich in valuable elements, is a hot topic in the non-ferrous metallurgy industry for recovering aluminum and other elements. Its utilization promotes a more rational allocation of resources and is crucial for improving the overall environmental situation. Firstly, the composition and physical and chemical properties of fly ash are analyzed. Then, the principle of recovering valuable elements from fly ash through roasting activation is expounded. Subsequently, the research progress of extracting aluminum, iron, lithium, gallium, vanadium and other elements from fly ash using the roasting activation-leaching method is systematically summarized. Finally, it is proposed that in the future, the roasting activation process parameters should be further optimized, and green and efficient subsequent separation technologies should be developed to promote the efficient, high-value and sustainable utilization of fly ash.

The recycling of valuable metals from spent lithium-ion batteries has significant economic and environmental benefits. The preparation of a low-viscosity eutectic solvent (DES) with excellent reducing properties using choline chloride, citric acid and ethylene glycol was studied. The DES was characterized by FT-IR, NMR and TG, and was used for the leaching of ternary lithium (NCM) cathode materials. The coordination dissolution mechanism of DES leaching NCM cathode materials was investigated by XRD, UV-Vis and FT-IR spectra. The results show that under the optimal leaching conditions of ethylene glycol addition of 30%, leaching temperature of 100 ℃, leaching time of 90 min, and liquid-solid mass ratio of 50/1 for DES, the leaching rates of Li, Mn, Co, and Ni in the cathode material are 95.98%, 96.73%, 98.58%, and 96.31%, respectively. The metal ions in the leachate can be efficiently recovered through the co-precipitation of anhydrous oxalic acid, and the precipitation rate of transition metal ions such as Mn, Co and Ni can reach over 95%. This recycling method can provide certaion technical reference for the green recycling of used lithium-ion batteries.