With the growing emphasis on environmental protection, discharge standards of chemical oxygen demand (COD) for smelting wastewater have also been continuously raised. In response to the problem that COD in drainage from a certain process in a copper smelting plant fluctuated between 50 and 100 mg/L, the sources of COD in drainage were traced by examining COD variation patterns of water samples in the technical process. In addition, properties of influent water samples, such as composition, COD variation patterns and contribution to the COD of the day, were analyzed. Traceability of COD throughout the process facilitated the source management and control of COD. Results showed that COD in drainage was correlated with that in the neutralization water in the technical process. COD in the neutralization water was mainly from six types of influents. Among them, wastewater from the first acidification stage (influent water ①), the second acidification stage (influent water ②), and the material preparation process (influent water ③) was main contributor to the amount of COD of the day. Considering that COD in drainage was mainly indicated as organic matter, high-performance liquid chromatography was used to identify pollutant source. It was found that organic components in drainage were related to influent water①, ②, and ③. It could be inferred that COD in drainage mainly originated from the three influents. Influent water①, ②, ③ and their mixture were treated by oxidation using YJY-O-1, resulting in 40%~65% COD reduction, therefore reducing fluctuation of COD in drainage. This study innovatively employed the pollutant source tracing method to identify sources of COD in smelting wastewater, and then controlled the amount of pollutants at the source, providing certain reference values for smelting wastewater treatment.

Flocculating sedimentation is a critical step in the thickening and dewatering of tailings during the backfilling process in mines. A certain iron mine in Liaoning has a complex and diverse mineral composition, with a significant proportion of fine-grained tailings, which poses challenges such as slow sedimentation rates and high overflow turbidity for the flocculating sedimentation process. To study the flocculating performance and sedimentation mechanism of tailings from the iron mine, experiments were conducted using whole tailings as the main test material. Results of natural sedimentation and flocculating sedimentation tests were compared. Single-factor method was combined to carry out flocculant selection tests were conducted, with clarity of the supernatant and sedimentation rate being the main evaluation indicators. Ultimately, 655S flocculant with the best sedimentation effect was selected for subsequent flocculating sedimentation experiments. By adjusting flocculant unit consumption and filling slurry concentration, the effects of these two factors on the performance of slurry flocculation and sedimentation were analyzed separately. When feed concentration was below 20%, the optimal flocculant addition was controlled in the range of 15±5 g/t, with the underflow concentration reaching 62.61%. Findings of this study provided a theoretical basis for improving the quality and efficiency of fine tailings backfilling in similar mines, and had significant practical value and engineering guidance significance.

Steel shed reinforced concrete combined support technology has been well applied in recent engineering practices. Based on tests and post-evaluations, this technology is considered highly suitable for complex geological conditions such as fractured and weak surrounding rocks in terms of technical comprehensive feasibility. However, there is little detailed research or analysis about this composite support method and related critical technologies. This paper, adopting methods of references study, practical cases study and data analysis, studied and summarized the technical feasibility of adopting steel shed reinforced concrete composite support method through post evaluation of the open slot section construction of a large copper mine's belt inclined shaft. It outlined key techniques and corresponding applicable situations of four core processes: construction of steel shed, construction of reinforced concrete arch skeleton, integrated construction of concrete work, and construction of transition section between open slot and underground tunnel. The aim was to provide references for support method selection and construction of copper mine roadway support under similar working conditions.

Cadmium zinc telluride (CdZnTe) thin films, characterized by a high atomic number, tunable optical bandgap, and excellent photoelectric conversion performance, hold significant potential in advanced applications such as thin-film photovoltaic cells, infrared imaging, and high-energy radiation detection. However, achieving low-cost fabrication and high-quality film formation remains a critical challenge for their industrial deployment. In this work, we systematically reviewed the vapor deposition techniques for CdZnTe thin films. While methods such as physical vapor transport, vacuum thermal evaporation, hot-wall epitaxy, magnetron sputtering, and close spaced sublimation offer advantages in simplicity and cost-effectiveness, they suffer from issues such as poor film uniformity and high lattice defect density. In contrast, molecular beam epitaxy and metal-organic chemical vapor deposition enable atomic-level precision and superior lattice integrity, but are constrained by high process costs and complex equipment, limiting their scalability. To enhance the quality of CdZnTe thin films, this work highlighted three key optimization strategies: (1) refining growth parameters for precise process control, (2) improving heteroepitaxial quality through interfacial buffer layer design, and (3) mitigating intrinsic defects via annealing treatments. Ultimately, we concluded that balancing film performance with production costs and overcoming the technical challenges of large-area uniform film deposition would be critical for the future advancement of CdZnTe thin films.

Surface defects in C19400 copper-iron alloys significantly degrade both electrical conductivity and mechanical properties, posing a key limitation on their application in high-end semiconductor packaging and electronic components. In this paper, origins and microscopic morphology of compositional defects in C19400 copper strips were systematically investigated. Distribution behavior of elements in the copper matrix was first predicted using Miedema model for thermodynamic calculations of Cu-Fe-P system. Subsequently, the defective samples were characterized in terms of microstructure and composition through methods including spark discharge optical emission spectrometry, scanning electron microscopy, and energy-dispersive spectroscopy. Results revealed the presence of various inclusion defects and precipitation in C19400 copper strips. Specifically, oxide inclusions appeared as irregular flakes; carbides aggregated as dark fine particles in localized areas; phosphides were distributed inside pits; hard inclusions were embedded as irregular particles within the pits, and precipitates aligned in elongated forms along the rolling direction. Traceability analysis indicated that compositional defects introduced during the melting and casting stages remained through manufacturing process to strip stage. Subsequent rolling and annealing treatments further altered the size and distribution of these inclusions. This study clarified the evolution path and microstructural characteristics of these defects, providing a theoretical and experimental basis for optimizing processing of C19400 and enhancing reliability of this material in high-end electronic applications.

With the shortage of copper resources, bimetal matrix composites partly replacing copper with steel have high economic value. To combine high thermal conductivity of copper with high strength of stainless steel, this paper successfully prepared T1 copper/316L stainless steel composites by single-pass cold rolling. Effects of annealing temperature on the microstructure and properties of T1 Cu/316L stainless steel composites were studied by scanning electron microscopy, hardness tests, tensile tests, tensile shear tests and electrical conductivity tests. Results showed that annealing can eliminate interface defects and improve interface structure. With the increase of annealing temperature, hardness and strength of copper/stainless steel composite materials gradually decreased, while elongation gradually increased, and electrical conductivity improved. After annealing at 700 ℃ for 2 h, excellent comprehensive properties can be obtained, with a yield strength of 539 MPa, a tensile strength of 689 MPa, an elongation of 33%, a shear strength of 191 MPa, and an electrical conductivity of 54.9%IACS.

In this study, Cu-Ni-Sn-P (C19040) alloy strip materials with different compositions were prepared by horizontal continuous casting followed by multiple cold rolling and heat treatment processes. Effects of Sn and Ni mass fraction variations on the mechanical properties, softening resistance, and thermal contraction of Cu-Ni-Sn-P alloy strip materials were investigated. Results indicated that an increase in Sn mass fraction enhanced mechanical properties and softening resistance of Cu-Ni-Sn-P alloy through solid solution strengthening. However, excessive Sn mass fraction exacerbated Sn segregation, which worsened the thermal contraction behavior. An increase in Ni mass fraction promoted the formation of more Ni-P precipitates, significantly improving the softening resistance. When mass fraction of Sn was 1.5% and that of Ni was 0.85%, the alloy exhibited superior comprehensive properties, with a hardness of 174HV, tensile strength of 565 MPa, elongation of 4.3%, thermal contraction rate of 0.006%, and softening resistance hardness of 141HV. These properties met the requirements for lead frame materials.

To prevent fire incidents, investigating fire traces and identifying the cause of the fire is a primary task in fire forensic evidence identification. Analysis of microscopic characteristics of copper conductors after a fire is an effective method for this purpose. This study simulated the temperature, time, and atmospheric conditions of a fire environment, generating fires caused by overcurrent faults, to investigate surface morphology, cross-sectional grain shape, and size of copper conductors after a fire. As the temperature increased and duration extended, oxidation degree of the copper conductor deepened, and grains continuously grew, exhibiting an axial shape. At 400 ℃, the grain size was 7~11 μm. At 600 ℃, it increased to 8~14 μm. At 800 ℃, it reached 13~17 μm. During the grain growth process, a large number of twins appeared due to low stacking fault energy. Average grain size of copper conductors was directly proportional to both annealing temperature and time, with temperature having a more significant impact. Linear fitting results showed that activation energy for grain boundary migration during grain growth was 0.68 kJ/mol. Under actual overcurrent fault conditions, the failure copper conductor formed molten beads and dendrites at the fracture site, indicating that an excessive current in the circuit caused the conductor to overheat, ultimately leading to fracture, with abnormal grain growth occurring near fracture zone.

Aluminum bronze alloys are a type of bronze alloy formed by mainly adding aluminum to copper, along with other alloying elements such as nickel and iron. Aluminum bronze alloys feature excellent mechanical properties, wear resistance and corrosion resistance, and are widely used as gears, valves and propellers. With rapid advancement of industrial technology, increasingly stringent requirements are being imposed on various properties of aluminum bronze. For traditional as-cast aluminum bronze, the presence of casting defects combined with complex multiphase structure makes it susceptible to failure under specific service conditions. The composition, microstructure, and properties of the alloy should be systematically optimized and improved in a targeted manner to meet specific requirements of service conditions. This paper investigated intrinsic relationship among preparation process, microstructural characteristics, as well as mechanical, corrosion, and wear properties of aluminum bronze alloys. It provided a comprehensive review of recent advancements in the development of high-performance aluminum bronzes through alloying, heat treatment, additive manufacturing, surface modification, and other processes. Corrosion resistance and friction-wear resistance of aluminum bronze under various technological conditions were systematically summarized and analyzed before potential future research directions were outlined.

Ammonia plays an important role in human activities, which is used widely in various industries with noticeable economic values. The main method currently used in ammonia synthesis is Haber-Bosch method, which requires high-temperature or high-pressure conditions, suffering low efficiency and high energy cost. In comparison, electro-reduction of nitrite for ammonia production is a NH₃-selective green chemistry process with low energy consumption. Cu-based materials are chosen as common catalyst materials in electro-production of ammonia owing to the abundance of source materials and high reaction activity towards nitrite. State-of-art Cu-based materials applied in electro catalysis of nitrate for ammonia production are mainly: metallic Cu, metallic-doped Cu-based materials, alloys, Cu oxide, Cu-containing polymetallic oxide, Cu-containing metal-organic framework (MOF), etc. These catalysts improve performances of ammonia production with different mechanisms, such as surface modulation, electron structure modulation, synergy of catalytic active centers, construction of built-in electric fields, etc. This paper aims to integrate performances and mechanisms of different Cu-based catalysts for electrochemical production of ammonia, and to provide reference for future research in this field.