Key Takeaways & Executive Findings
- •• Optimal reduction efficiency achieved at C/O molar ratio of 1.2, reaching ~90% reaction fraction. • Addition of CaF2 lowers melting point and viscosity, enhancing reduction rate. • Reduction rate increases with temperature, controlled by gas-phase diffusion. • Two-stage kinetics with activation energies of 56.10 and 100.52 kJ/mol, providing predictive equations.
Abstract
Silicomanganese dust contains large amounts of valuables, such as Si and Mn, which can be used as raw materials for the smelting of silicomanganese. However, the direct addition of dust to the submerged arc furnace can influence the permeability of burden due to the fine particle size of dust, which results in incomplete reduction reactions during the smelting process. In this paper, silicomanganese dust, graphite powder, and other additives were pressed to form carbon-containing dust briquettes, and the self-reduction process of the dust briquettes was investigated through the isothermal thermogravimetric method with different carbon–oxygen (C/O) molar ratios, contents of fluxing agents, and reduction temperatures. Various reduction kinetic models for dust briquettes at different temperatures were established. The results show that the reaction fraction of the dust briquettes was about 90% at a C/O molar ratio of 1.2 with optimal reduction efficiency. The addition of CaF2 contributed to the decrease in the melting point and viscosity of dust briquettes, which increased their reduction rate. As the reduction temperature increased, the reduction rate of dust briquettes increased. The reduction reaction rate of dust briquettes was controlled through gas-phase diffusion. Meanwhile, their reduction process was analyzed kinetically, with the reaction time of 5 min as the dividing line. The apparent activation energies for the two diffusion stages were 56.10 and 100.52 kJ/mol, respectively. The kinetic equations are expressed as [1 − (1 − ƒ)1/3]2 = 0.69e−56100/(RT)t and [1 − (1 − ƒ)1/3]2 = 2.06e−100520/(RT)t.
1. Introduction
Solid waste application is important in the strategy for increased recycling, and the utilization of metallurgical dust can improve the utilization efficiency of mineral resources. Silicomanganese dust indicates the solid waste generated during the smelting of silicomanganese, and it contains large amounts of Si and Mn and a small amount of alkali metal elements [1]. According to statistics, for each ton of silicomanganese produced, approximately 120 kg of dust containing between 25wt% and 35wt% of manganese is generated, and such value is higher than the manganese content in most low-grade manganese ores [2–3]. The global production of silicomanganese exceeds 16 million tons, and approximately 320000 t of silicomanganese dust was generated in 2020. Manganese content is estimated at around 112000 t, which indicates its crucial potential for recycling [3–5].
Currently, the treatment methods for silicomanganese dust primarily involve pyrometallurgical and hydrometallurgical processes. The hydrometallurgical method faces challenges, such as low alkali metal removal efficiency and the generation of harmful wastewater [2,6]. The pyrometallurgical process utilizes silicomanganese dust as a raw material for sintering. Given the fine particle size of dust, whether sintered under negative or positive pressure, considerable dust loss occurs, and it affects the permeability of the sintering process and reduces equipment production efficiency. In addition, the enrichment of alkali metals in silicomanganese dust can cause damage to the equipment to some extent [7–8]. Previous research findings indicate the effectiveness of converting carbon-containing silicomanganese dust briquettes for recovery through the pyrometallurgical process. This approach not only addresses a substantial amount of dust but also achieves positive outcomes in the removal of heavy metals, such as zinc and lead [9].
Loading authentic research manuscript (Pages 1–5)...
Ju Xu, Guojun Ma, Jie Xu, Mengke Liu, Xiang Zhang, Dingli Zheng, Junlong Li (2025). Kinetics of isothermal reduction of carbon-containing silicomanganese dust. Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报). https://doi.org/10.1007/s12613-024-3064-8
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the optimal C/O molar ratio for the reduction of silicomanganese dust briquettes?
The optimal C/O molar ratio is 1.2, achieving a reaction fraction of about 90% with optimal reduction efficiency.
How does the addition of CaF2 affect the reduction process?
CaF2 lowers the melting point and viscosity of the briquettes, which enhances the reduction rate.
What is the rate-controlling step in the reduction of dust briquettes?
The reduction reaction rate is controlled by gas-phase diffusion.
What are the apparent activation energies for the two diffusion stages?
The apparent activation energies are 56.10 kJ/mol for the first stage and 100.52 kJ/mol for the second stage.
What is the significance of this research for industrial application?
This research provides a kinetic model and optimal conditions for recycling silicomanganese dust via briquetting, improving resource utilization and reducing environmental impact.
Related Technical Papers & Translations
Direct Repair of the Crystal Structure and Coating Surface of Spent LiFePO4 Materials Enables Superfast Li-Ion Migration
The rapid accumulation of spent LiFePO4 (LFP) cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies. In this context, direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials, offering a streamlined pathway to restore their electrochemical functionality. We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP. The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode–electrolyte interface, giving a remarkable rate capability with specific capacities of 122 mAh g−1 at 5C and 106 mAh g−1 at 10C (1C = 170 mA g−1). It also maintained capacities of 110.7 mAh g−1 (5C) and 84.1 mAh g−1 (10C) after 400 cycles. It could be used in harsh environments and could be stably cycled at subzero temperatures (−10 and −20 °C) and in solid-state electrolyte batteries. Life cycle assessment combined with economic evaluation using the EverBatt model reveals that this direct regeneration approach has high economic and environmental benefits.
Oxide Semiconductor for Advanced Memory Architectures: Atomic Layer Deposition, Key Requirement and Challenges
Oxide semiconductors (OSs), introduced by the Hosono group in the early 2000s, have evolved from display backplane materials to promising candidates for advanced memory and logic devices. The exceptionally low leakage current of OSs and compatibility with three-dimensional (3D) architectures have recently sparked renewed interest in their use in semiconductor applications. This review begins by exploring the unique material properties of OSs, which fundamentally originate from their distinct electronic band structure. Subsequently, we focus on atomic layer deposition (ALD), a core technique for growing excellent OS films, covering both basic and advanced processes compatible with 3D scaling. The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced. Furthermore, material design strategies, such as cation selection, crystallinity control, anion doping, and heterostructure engineering, are discussed. We also highlight challenges in memory applications, including contact resistance, hydrogen instability, and lack of p-type materials, and discuss the feasibility of ALD-grown OSs as potential solutions. Lastly, we provide an outlook on the role of ALD-grown OSs in memory technologies. This review bridges material fundamentals and device-level requirements, offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.
Laser powder bed fusion of biodegradable Zn-4Cu alloy: Processing, microstructure and properties
Zn's natural degradability and biocompatibility make it a promising candidate for implants, however, its mechanical properties remain insufficient for bone applications. In this study, the performance of Zn was enhanced by developing Zn-Cu alloys via laser powder bed fusion (LPBF). Optimal LPBF parameters for forming stable tracks were achieved by adjusting laser power and scanning speed. Under optimized conditions of 100 W and 100 mm/s, high-density (99.58%) Zn-Cu alloys with improved hardness (68.2HV) and yield strength (160 MPa) were achieved. These improvements are attributed to solid solution strengthening, segregation strengthening, and grain refinement. The Zn-Cu alloys also demonstrated favorable degradation behavior, with a rate of 0.16 mm/year. This degradation is primarily driven by micro-galvanic corrosion between the CuZn5 phase and Zn matrix, along with refined grains and increased grain boundary density. This work demonstrates a viable strategy for fabricating Zn-based implants with enhanced structural integrity and mechanical performance via LPBF.