Key Takeaways & Executive Findings
- •• Hydrogen-assisted mineral phase transformation enables efficient iron recovery (90.11%) from laterite nickel ore tailings, achieving a final iron grade of 61.00 wt%. • Pre-treatment at 950°C for 15 min reduces sulfur content from 2.09 wt% to 0.295 wt%, mitigating environmental hazards. • Synergistic desulfurization using wet scrubbing and limestone achieves an overall desulfurization rate of 85.83%. • The process offers a sustainable route for valorizing HPAL tailings, with potential for industrial scale-up.
Abstract
This study explores a hydrogen-assisted mineral phase transformation process with synergistic desulfurization for the efficient recovery of iron from the high-pressure acid leach (HPAL) tailings of laterite nickel ore. HPAL tailings containing 51.50wt% iron and 2.09wt% sulfur present environmental challenges due to their sulfur content. Pre-treatment at 950°C for 15 min successfully reduced the sulfur content to 0.295wt% and increased the iron grade to 57.66wt%. Further hydrogen-assisted mineral phase transformation at 520°C for 30 min, using 40vol% hydrogen and a gas flow rate of 600 mL·min–1, resulted in a product with an iron grade of 61.00wt% and 90.11% iron recovery. The overall desulfurization rate reached 85.83% when wet scrubbing and limestone were used to capture the sulfur. This study demonstrates the efficiency of this hydrogen-assisted process for sustainable iron recovery and sulfur removal from laterite nickel ore tailings, with potential for industrial applications.
1. Introduction
The rapid expansion of industries such as electric vehicles and ternary lithium-ion batteries has intensified the demand for critical metal resources, including iron (Fe), cobalt (Co), and nickel (Ni) [1–4]. With the depletion of high-grade nickel ore reserves, low-grade laterite nickel ores, which constitute approximately 75% of global nickel, have emerged as a crucial source for nickel extraction [5–7]. However, these ores have a low metal content, typically containing 0.9wt%–2.6wt% Ni, 0.01wt%–0.2wt% Co, and 40wt%–55wt% Fe, and their complex mineralogical composition renders traditional metallurgical extraction processes inefficient. High-pressure acid leaching (HPAL) is a key method for extracting Ni from laterite ores [8–10].
Despite its effectiveness in nickel recovery, HPAL produces large volumes of acid-leached tailings containing 35wt%–40wt% Fe, making it a potentially valuable secondary source of Fe. However, these tailings contain over 2wt% sulfur (S), which is a hazardous impurity that poses significant environmental and processing challenges [11–13]. The high S content not only degrades the quality of Fe recovered from the tailings but also results in the release of sulfur dioxide (SO2) during further processing, contributing to environmental issues such as acid rain [14]. Consequently, while these tailings represent an important iron-bearing secondary resource, their direct utilization is limited by both their high S content and the difficulty of economically viable processing. Currently, most tailings are disposed of in landfills or buried underground, leaving their full potential largely untapped [15].
Loading authentic research manuscript (Pages 1–5)...
Na Zhao, Yuchao Qiu, Sainan Qi, Mengyu He, Qianwen Li, Yongsheng Sun (2025). Hydrogen-assisted mineral phase transformation for iron recovery and sulfur removal from laterite nickel ore tailings. Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报). https://doi.org/10.1007/s12613-025-3121-y
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 main objective of this study?
The study aims to develop a hydrogen-assisted mineral phase transformation process for efficient iron recovery and sulfur removal from laterite nickel ore tailings, addressing environmental challenges and enabling sustainable resource utilization.
How does the hydrogen-assisted process work?
The process involves pre-treatment at 950°C to reduce sulfur content, followed by hydrogen-assisted reduction at 520°C with 40vol% hydrogen, which transforms iron minerals to enhance magnetic separation and iron recovery.
What are the key results achieved?
The process achieved an iron grade of 61.00 wt% with 90.11% iron recovery, and an overall desulfurization rate of 85.83% when combined with wet scrubbing and limestone capture.
Why is sulfur removal important in this context?
Sulfur is a hazardous impurity that degrades iron quality and releases SO2 during processing, contributing to acid rain. Removing sulfur is essential for environmental compliance and improving the value of recovered iron.
What are the potential industrial applications?
The process offers a sustainable and efficient method for recovering iron from HPAL tailings, which are currently landfilled, and can be scaled up for industrial use in ironmaking and steel production.
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.