Chu Cheng

In this study, an innovative idea of preparing dual-phase micro-nano particle reinforced copper-based materials by one-step aluminothermic reduction method is proposed. That is, copper-based materials containing uniformly distributed dual-phase micro-nano particle reinforced phases were obtained by aluminothermic reduction reaction directly using aluminum powder, vanadium oxide, copper oxide, etc. , as raw materials. A systematic investigation was conducted on the thermodynamic behavior of the reaction system for dual-phase micro-nano particle-reinforced copper matrix composites, accompanied by comprehensive characterization of the resultant metallic alloys and slag phases. The results show that the dual-phase micro-nano particle composite reinforced copper-based materials were successfully prepared by aluminothermic reduction method. There are 1–10 μm micron vanadium particles and 60–200 nm nano-vanadium-aluminum master alloy phases dispersed in the microstructure of copper-based materials. With the increase in V ₂ O ₅ ratio, the size of micron vanadium particles in the prepared dual-phase micro-nano particle reinforced copper-based material gradually increases, and the size of Al _x V _y phase dispersed in the matrix gradually decreases. The inclusions in the copper matrix are mainly Al ₂ O ₃ , and the reducing slag is mainly composed of CaAl ₄ O ₇ , CaAl ₂ O ₄ , and Cu ₂ O.

As the grade of the copper concentrate decreases and its composition becomes increasingly complex, the silver content in anode plates cast after fire refining increases, leading to a higher silver content in the copper cathode during electrorefining and a substantial loss of precious metals. This study investigates the impact of 5-amino-1H tetrazole (5-AT) on reducing silver in copper cathodes during electrorefining with high silver content anode plates. 5-AT forms an “adsorption layer” on the anode surface, reacting with Ag⁺ released by the anode to form a precipitate and prevent Ag⁺ from entering the electrolyte. This process agglomerates fine Ag-Se compounds and AgCl particles, creating larger anode slime particles that settle quickly, thus inhibiting fine silver-containing particles from adhering to the cathode. Furthermore, 5-AT adsorbs on the cathode, binding with Cu⁺ and promoting the Cu²⁺ electrodeposition process while inhibiting Ag⁺ electrodeposition. This facilitates uniform copper cathode grain growth and reduces inclusions in the copper cathode. The grain size of the copper cathode initially decreases and then increases as the concentration of 5-AT increases. At an optimal 5-AT concentration of 15 mg/L, the Ag content in the copper cathode decreased from 6.9 ppm to 4.7 ppm, indicating the potential efficacy of 5-AT in improving the quality of electrorefined copper.

CuW is widely used in high‐voltage electrical switch contacts, rocket nozzle throat linings, electronic packaging materials and other major high‐end technologies. CuW is typically fabricated using infiltration and high‐temperature sintering methods based on powder metallurgy. As CuW composites fabricated using these methods have the disadvantages of low density and uneven microstructural distribution, the preparation of CuW composites by aluminothermic reduction was proposed. However, some Al ₂ O ₃ inclusions produced by aluminothermic reduction do not effectively combine with the slag‐making agent CaO to form a liquid slag phase and remain in the CuW composite, resulting in a small number of Al ₂ O ₃ inclusions in the CuW composites. To overcome this problem, a novel methodology for strengthening metal‐slag separation through in situ slagging is proposed. In this study, CuW composites were prepared by metallothermic reduction using Al, AlCa and AlMg as reducing agents. The CuW composites and slag samples were systematically analyzed. The results indicate that the Al ₂ O ₃ particles produced by aluminothermic reduction can be modified in situ into calcium aluminate and MgO·Al ₂ O ₃ with lower melting points by using AlCa and AlMg alloys as reducing agents, which strengthens the metal‐slag separation. Moreover, AlCa and AlMg exhibited refining effects on the tungsten particles of the CuW composite, where the effect of AlMg was greater than that of AlCa. The slag obtained using the AlCa alloy as a reducing agent was mainly composed of CaWO ₄ , CaAl ₄ O ₇ and Ca ₄ Al ₆ O ₁₂ WO ₄ , whereas that obtained using the AlMg alloy was mainly composed of CaWO ₄ , MgAl ₂ O ₄ and Ca ₄ Al ₆ O ₁₂ WO ₄ .

Titanium alloys have excellent properties and are widely used in aerospace, medicine, chemical industry, and other fields. With the rapid development of the powder metallurgy and 3D printing industries, the demand for ultra-fine titanium alloy powders has increased significantly. It should be noted that the particle size of titanium alloy powders determines the application process. However, the high melting point of titanium and titanium alloys and the limitation of many factors, such as the prepared powders being easily contaminated by secondary pollution, make the preparation cost higher, which restricts their promotion and application. In this study, the research progress of micro and nano titanium alloy powder preparation process is described, and the existing problems of various processes are analyzed and discussed, and it is proposed that the direct reduction in TiO ₂ to obtain micro and nano titanium alloy powder is the key research direction in the future. In particular, the preparation of micro and nano titanium alloy powder by “calciothermic self-propagation process” has great industrial potential.

The prediction of equilibrium components for chemical reactions is a considerable section in the metallurgical industry. According to the ion and molecule coexistence theory (IMCT), a modified mass action concentration model based on a thermodynamic database is proposed in this paper, which complys with the law of mass conservation and can be applied in the batching process for Al-Ti-Ca-oxide system that originates from SHS (Self-propagating High-temperature Synthesis) metallurgy. The trend for slag and alloy component under different batching conditions are in good agreement with experiment, while the difference between the theoretical calculation and experiment can be attributed to the deviation from the thermodynamic equilibrium. The modified mass action concentration model with melts and slag can be used to predict the composition and content of the system when equilibrium is achieved at a certain temperature under a specific material ratio, which is conducive to reducing the cost of the experiment and predicting the operability of the actual process. Moreover, it is believed that this thermodynamic insight may has certain application prospects in these metallurgical procedure based on the equilibrium process.

CuW composite fabricated by powder metallurgy using ultrafine metal powders as raw materials has the disadvantages such as uneven microstructure and low compactness. A novel method of synthesizing an as-cast CuW composite ingot via an aluminothermic coupling with silicothermic reduction is presented; a low-melting-point CaO–Al ₂ O ₃ –SiO ₂ slag is formed by adding CaO as a slag former, effectively reducing Al ₂ O ₃ inclusion in the CuW composite. In this study, the effects of CaO addition on the novel synthesis of the CuW composite via the aluminothermic coupling with silicothermic reduction are investigated. The result shows that CaO affects the removal of large particles (≥6 µm) but not the removal of small particles (≤4 µm). With the increase in the ratio of CaO ranging from 0 to 1.0, the inclusions in the CuW composites gradually transform from Al ₂ O ₃ to calcium aluminates, which are conducive to the separation of the metal and slag. The contents of Si and O in the CuW composites gradually decrease from 9.40 and 14.00% to 6.10 and 3.50%, respectively, while those of Al and Ca gradually increase from 2.54 and 0.02% to 3.83 and 0.26%, respectively.