Iron Resources Research Articles

Structural Basis and Mechanism of a Unique Haemophore in the Haem-Iron Acquisition by Riemerella anatipestifer.

Several bacterial pathogens employ haemophores to scavenge haem from host haemoprotein to obtain an iron source. However, no homologues of well-characterized haemophores are found in Riemerella anatipestifer, a bacterium belonging to the order Flavobacteriales that encodes haem uptake systems. Herein, a unique haemophore RhuH is characterized in this bacterium. R. anatipestifer used RhuH to grow when duck hemoglobin serves as the sole iron resource. RhuH is secreted as a component of outer membrane vesicles. Recombinant RhuH exhibited a high binding affinity for haem (Kd of 3.44 × 10-11m) and can extract haem from duck hemoglobin. X-ray crystallography elucidated the 3D structure of RhuH at 2.85 Å resolution, showing a dimeric conformation with each monomer exhibiting a unique structure. Structure modeling of RhuH-haem, coupled with mutagenesis, haemin utilization, and binding affinity assays, show that haem is captured in the β-barrel-like region, displaying the classic iron coordination. The RhuH homologues are predominantly distributed in Weeksellaceae and Flavobacteriaceae. Finally, the homologues of RhuH in Riemerella columbina, Flavobacterium columnare, and Flavobacterium soli are used as a proof of concept, demonstrating that these homologues exhibit conserved structures and functions.

Characterization of Physical and Chemical Properties of Multi-Source Metallurgical Dust and Analysis of Resource Utilization Pathways

Steel metallurgical dust, characterized by a substantial output, minute particle size, and intricate composition, poses a considerable risk of environmental contamination while simultaneously embodying an exceptionally high potential for recycling. To achieve its resource utilization, chemical analysis, particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), Mössbauer spectroscopy, and water leaching methods were employed to investigate the chemical compositions, particle size distributions, phase compositions, and microscopic morphologies of blast furnace bag dust, sintering dust, converter fine dust, and electric arc furnace dust from steel plants. The results indicate that the four types of dust have extremely fine particle sizes, with the main distribution range of particle size being less than 100 μm. The main constituent element is Fe (19–56%), and it also contains Zn (1.4–33.5%), Pb, K, C, and other valuable elements. Alkali metals in blast furnace bag dust and sintering machine head dust existed mainly in the form of chloride. The zinc phases in sintering machine head dust and converter fine dust were ZnFe2O4, and the zinc phases in blast furnace bag dust were ZnCl2 and ZnFe2O4. Zinc in electric furnace dust was composed of ZnO and ZnFe2O4, accounting for 70.31% and 23.12%, respectively. There are significant differences in the types and contents of valuable elements among various dusts, making it difficult to achieve full-scale recovery through a single process. In view of this, a process of “in-plant recycling of harmless dusts—collaborative treatment of harmful dusts” has been proposed. Based on the characteristics of metallurgical dusts, multiple processes are used for collaborative treatment (using hydrometallurgical and pyrometallurgical methods), which can not only directly recover iron resources from dusts within the plant, but also avoid the waste of valuable elements such as Zn, Pb, K, Na, etc. It is hoped that the above work can provide a reference for steel enterprises to achieve full-scale and high value-added treatment of metallurgical dusts.

High-Stable All-Iron Redox Flow Battery with Innovative Anolyte based on Steric Hindrance Regulation.

All-soluble all-iron redox flow batteries (AIRFBs) are an innovative energy storage technology that offer significant financial benefits. Stable and affordable redox-active materials are essential for the commercialization of AIRFBs, yet the battery stability must be significantly improved to achieve practical value. Herein, ferrous complexes combined with the triisopropanolamine (TIPA) ligand are identified as promising anolytes to extend battery life by reducing cross-contamination due to a pronounced steric hindrance effect. The coordination structure and failure mechanism of our Fe-TIPA complexes were determined by molecular dynamics simulation and spectroscopic experiments. By coupling with [Fe(CN)6]4-/3-, Fe-TIPA/Fe-CN AIRFBs retained excellent stability exceeding 1831 cycles at 80 mA ⋅ cm-2, yielding an energy efficiency of ~80 % and maintaining a steady discharge capacity. Moreover, the all-soluble electrolyte was tested in an industrial-scale Fe-TIPA/Fe-CN AIRFB prototype energy storage system, where an energy efficiency of 81.3 % was attained. Given the abundance of iron resources, we model the TIPA AIRFB electrolyte cost to be as low as 32.37 $/kWh, which is significantly cheaper than the current commercial level. This work demonstrates that steric hindrance is an effective measure to extended battery life, facilitating the commercial development of affordable flow batteries.

A Novel Technique for Preparation and Separation of Iron Carbide from Sintering Dust

Sintering dust is a typical refractory secondary iron resource. A technology‐based utilization of sintering dust as iron carbide by applying chlorination, carburization, and magnetic separation is proposed. Under optimized conditions, an electric furnace burden comprised of 83.51% Fe and 6.52% C and with a corresponding iron recovery rate of 81.21% is prepared. Meanwhile, 96.97% Pb can be removed by chlorination and magnetic separation. Furthermore, the separation mechanism is revealed using scanning electron microscopy, X‐ray powder diffraction, and optical microscopy. The results show that sodium sulfate can promote the carburizing efficiency of sintering dust, strengthen the growth of iron carbide particles, and improve the embedding relationship between iron carbide and gangue minerals, which significantly promotes the separation efficiency. The study demonstrates that the preparation of iron carbide from sintering dust using the proposed technology is a feasible method.

Endogenous iron-enriched biochar loaded nickel-foam cathode in electro-Fenton for ciprofloxacin degradation: performance, mechanism and DFT calculation

Steel mill wastewater sludge, with abundant endogenous iron resources, could be pyrolyzed into iron-enriched biochar (SBC) in one step and loaded onto nickel foam cathode (Ni-Foam) to construct a heterogeneous electro-Fenton system (SBC@Ni-Foam/EF). The purpose of this study were to optimize SBC@Ni-Foam/EF for efficient ciprofloxacin (CIP) removal, and its degradation mechanism and pathway in the presence of endogenous iron were elucidated by DFT calculation. The results showed that the highest CIP degradation efficiency (95.11 %) was achieved at a SBC pyrolysis temperature of 800 °C, an initial solution pH of 3, a Na2SO4 concentration of 0.05 mol L−1, a current density of 40 mA cm−2, and an aeration rate of 200 mL min−1. The degradation of CIP by SBC@Ni-Foam/EF was dominated by cathodic catalytic oxidation, and ·OH played a major role in the CIP degradation process. Combined with characterization and DFT calculation, the endogenous iron was dispersed in the stable Fe3O4 crystalline phase, which provided surface defects and catalytic sites for the cathode and promoted H2O2 activation to generate ·OH through iron cycling. The possible degradation pathways of CIP were proposed to include the cleavage of piperazine and quinolone rings, hydroxylation, and substitution or detachment of fluorine, etc., and the overall toxicity of the intermediates was alleviated after SBC@Ni-Foam/EF treatment. Therefore, this study was expected to achieve a win–win situation for iron-enriched sludge biomass resource utilization and CIP wastewater treatment.

Sintering, microstructure and mechanical properties of anorthite-based ceramics prepared from iron-extracted steel slag

Steel slag is a promising source of ceramic materials, but it causes a waste of iron resources and inferior ceramic performance because the slag contains over 30 % iron oxides. To deal with this problem, we proposed a two-step utilization process for steel slag, including iron extraction by smelting reduction and ceramics preparation from residual slag. In this work, the effect of the reduced slag addition on phase constituents, microstructure, and properties of this novel ceramic was studied. The major crystalline phase is anorthite for all the ceramics. Although abundant liquid is expected theoretically in conventional ceramics at 1175 °C, it did not achieve vitrification until 1250 °C. The slag addition plays different roles in sintering under various slag contents. After introducing 15 wt% slag, the sintering and pore elimination are accelerated significantly because of the slag’s fluxing effect although the ceramic shows no change in the theoretical liquid content. The ceramics have no advantage in producing liquids with further increasing the slag content. Therefore, limited densification is observed with 30 wt% slag addition owing to the lack of liquid phase. Fortunately, solid solution diopside is largely generated in the anorthite matrix with 45 wt% slag addition, greatly enhancing the ion diffusion and grain growth. This effect contributes to a highly dense and uniform sintered structure with small rounded pores at 1175 °C, at which its flexural strength increases by 92 % compared to the conventional ones. However, a higher slag addition in the ceramic should be avoided to ensure satisfactory structure integrity.

Practical experience to theoretical innovation: A model for recovering metal resources from industrial solid waste − A case study of copper smelting slag

Industrial solid waste (ISW), a byproduct of modern industrial production, poses significant challenges to sustainable development due to limitations in economic and technical capabilities. Despite containing valuable metal resources, the lack of a coherent approach to its treatment has hindered progress in addressing this longstanding issue. In response, we introduce an innovative model for metal resource recovery from ISW (ISWMRR), with a specific focus on copper smelting slag (CSS) as a prevalent example. This study underscores the efficacy of mineral phase reconstruction technology in converting CSS from a liability to an asset, thereby ensuring a sustainable stream of high-quality raw materials for green steel production amid declining iron ore reserves. Experimental findings indicated that employing the ISWMRR model enabled the successful production of iron products from CSS, yielding an iron concentrate with a TFe (total iron) fraction of 87.21 wt% and iron recovery of 91.24%. This approach facilitated the cost-effective, environmentally friendly, and efficient recovery of iron resources from CSS. By furnishing a novel theoretical framework, our research seeks to guide scientists and industry stakeholders engaged in ISW management.

Separation and extraction of iron resources from hazardous electric arc furnace (EAF) steel slag: Aggregation of Fe-rich layers, magnetic separation, powder characterization

China's electric arc furnace (EAF) slag reserves are huge, the problems of EAF slag resource application need to be solved urgently. In this study, high temperature holding and slow cooling treatment were used to treat the slag. The phase and structure of the slag were analysed by means of X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. To analyse the migration pattern of iron elements and to study the interaction between EAF slag basicity and magnetic separation efficiency. The results show that, there is an obvious layering phenomenon during the cooling slag, and the top layer is the Fe-rich layer. The slow cooling treatment makes the Fe-rich phase grow sufficiently and improves the dissociation efficiency of the Fe-rich phase in the crushing process. As the basicity increases, the thickness of the iron-rich layer gradually decreases and the iron element is transferred to the RO phase, while the concentrate yield decreases. Multi-stage wet weak magnetic separation of treatment slag resulted in the highest concentrate yield of 49.05 % at an basicity of 1, with a T.Fe content of 56.711 %, and 70.32 % of the iron component entering the concentrate. The concentrate can be returned to the steelmaking process instead of the charge, and the tailings can be used to make high value-added products.

Uncovering Availability of the Secondary Iron Resources in China: Integrating Material Flow Analysis and Secondary Resources Reserve Assessment.

As the largest iron and steel producer, China still cannot meet its demand of iron and steel only through domestic primary supply in the last few decades. Hence, secondary iron resources are increasingly significant in meeting China's iron supply and demand balance. However, the secondary iron resource availability in China and how it impacts the future supply demand balance were still insufficiently discussed. In this work, we developed a material flow analysis and secondary resources reserve assessment (MFA-SRRA) integrated model, assessed secondary iron resources availability, and conducted a supply demand analysis through nine scenarios for irons in China. The results showed that China's secondary iron reserves will increase from 8.9 Gt in 2021 to 14.04 to 19.01 Gt in 2050. With the increasing secondary iron supply, more than 60% of iron ore as a source of steelmaking can be replaced by 2050. Landfills, as a significant reserve of iron but always ignored, will accumulate 1.42-1.51 Gt secondary iron resources by 2050 and should be noticed to be mined and utilized in the future. Last, we suggest that promoting innovation in landfill mining technology and making sustainable material management policies are urgent to prevent these secondary iron resources from becoming real waste.

A Novel Fabrication of Hematite Nanoparticles via Recycling of Titanium Slag by Pyrite Reduction Technology.

An enormous quantity of titanium slag has caused not merely serious environment pollution, but also a huge waste of iron and sulfur resources. Hence, recycling iron and sulfur resources from titanium slag has recently been an urgent problem. Herein, hematite nanoparticles were fabricated through a pyrite reduction approach using as-received titanium slag as the iron source and pyrite as the reducing agent in an nitrogen atmosphere. The physicochemical properties of the hematite nanoparticles were analyzed using multiple techniques such as X-ray diffraction pattern, ultraviolet-visible spectrophotometry, and scanning electron microscopy. The best synthesis conditions for hematite nanoparticles were found at 550 °C for 30 min with the mass ratio of 14:1 for titanium slag and pyrite. The results demonstrated that hematite nanoparticles with an average particle diameter of 45 nm were nearly spherical in shape. The specific surface area, pore volume, and pore size estimated according to the BET method were 19.6 m2/g, 0.117 cm3/g, and 0.89 nm, respectively. Meanwhile, the fabricated hematite nanoparticles possessed weak ferromagnetic behavior and good absorbance in the wavelength range of 200 nm-600 nm, applied as a visible light responsive catalyst. Consequently, these results show that hematite nanoparticles formed by the pyrite reduction technique have a promising application prospect for magnetic material and photocatalysis.

Uncovering the key features of iron metabolism in Pakistan from 2005 to 2020: A dynamic material flow analysis

Iron is a crucial metal for Pakistan's growth, especially in its infrastructure and industrial sectors. However, the key features of iron metabolism are still unclear in this country, which makes it difficult to prepare appropriate iron management policies. In order to fill this knowledge gap, we employ a dynamic material flow analysis method to uncover the key features of iron metabolism in Pakistan for the period of 2005–2020. The result shows that a total of 2.057 Mt of iron ore was extracted during this study period. Pakistan heavily relied on importing iron resources to meet its demand, mainly from China (13.14 %), Japan (6.86 %), the United Arab Emirates (6.24 %), and the United Kingdom (6.27 %). Meanwhile, China (43.5 %) and the United Arab Emirates (19.82 %) are the top two buyers of Pakistan's iron-related products. In addition, our results indicate that iron recycling was insufficient in Pakistan, with a recycling rate of only 15 %. Finally, several policy recommendations are proposed by considering the Pakistan's reality in order to enhance the overall iron resource efficiency.

Role of lactoferrin in the treatment of upper respiratory tract infections

Introduction Lactoferrin is a glycoprotein belonging to the group of transferrins found in most body fluids. It has been shown to possess antimicrobial, anti-inflammatory, immunomodulatory and anticancer properties. The increasing availability and widespread use of dietary supplements containing lactoferrin have been observed as supportive measures in managing various infections. Aim of the study The objective of this study is to summarize the current knowledge regarding the anti-infective - mostly antiviral - effects of lactoferrin and the justification for its use in the treatment of upper respiratory tract infections. Knowledge summary Scientific research has consistently confirmed the effectiveness of lactoferrin against pathogenic microorganisms. The antibacterial effect of this protein is based mainly on the management of available iron resources - an ingredient necessary for bacterial growth. On the other hand, the antiviral activity of this protein is based on the induction of interferon production. Conclusion Dietary supplements containing lactoferrin are approved by the US Food and Drug Administration (FDA) for supportive use in infections. Lactoferrin exhibits antimicrobial activity supported by research in specific infections. It has a good tolerance and safety profile, therefore it seems that it can be used adjunctively in this indication.

One-step hydrothermal synthesis of iron phosphate dihydrate with ferric salt dephosphorized sludge

This study presents a novel approach for one-step hydrothermal synthesis of iron phosphate dihydrate (FePO4·2 H2O) using ferric salt dephosphorization sludge (FePs) from liquor wastewater. The gradual dissolution of FePs, facilitated by increasing temperatures and concentrations of phosphoric acid, releases Fe3+ and PO43- ions during hydrothermal reactions. These ions recrystallize into iron phosphate dihydrate and iron hydroxy-phosphate (Fe5(PO4)4(OH)3·2 H2O) depending on the conditions. Through a single-factor experiment, the effects of total organic carbon (TOC) in FePs and hydrothermal reaction conditions on the phase and morphology of the products were investigated, then the recrystallization process of iron phosphate dihydrate was also simulated by molecular dynamics. The first charge/discharge capacities of lithium iron phosphate (LFP) batteries synthesized from the optimal products were 153.1 and 149.4 mAh·g−1 at 0.1 C rate, respectively, and the cycling performance could be maintained under different rates, which has a good application prospect. The reaction fully utilized the iron and phosphorus resources in FePs, and the filtrate could be recycled to avoid the waste of resources, which provided a new idea for the resource utilization of FePs.

Preparation of cementing material and recovery of iron resources using converter slag

This study aims to optimize the modification of blast furnace slag and converter slag using dust removal ash as a reducing agent, with the dual goals of enriching cementitious materials and recovering iron resources. The results show that the pulverization effect of the modified slag is optimized when the dust removal ash addition ratio is 14 wt%, the reduction temperature is 1450 °C, and the reduction time is 30 min. Under these conditions, the pulverization and iron recovery rates reached 65.23 % and 60.85 %, respectively. The composition of the reduction-modified product is influenced by the particle size of the reduction product, which in turn affects its phase composition. The main phases of small particles (particle size < 0.150 mm) identified were magnesium rose pyroxene (Ca3Mg(SiO4)2, C3MS2) and dicalcium silicate (γ-Ca2SiO4, γ-C2S). The main phases of large particles (particle size > 0.150 mm) identified were dicalcium silicate (β-Ca2SiO4, β-C2S) and Ca2Fe2O5. Iron primarily exists in the form of an alloy and cementite, while P is dispersed in the iron beads in the form of Fe3P, Fe2P, and Mn2P in a striped configuration.

Retrospect on the Ground Deformation Process and Potential Triggering Mechanism of the Traditional Steel Production Base in Laiwu with ALOS PALSAR and Sentinel-1 SAR Sensors.

The realization of a harmonious relationship between the natural environment and economic development has always been the unremitting pursuit of traditional mineral resource-based cities. With rich reserves of iron and coal ore resources, Laiwu has become an important steel production base in Shandong Province in China, after several decades of industrial development. However, some serious environmental problems have occurred with the quick development of local steel industries, with ground subsidence and consequent secondary disasters as the most representative ones. To better evaluate possible ground collapse risk, comprehensive approaches incorporating the common deformation monitoring with small-baseline subset (SBAS)-synthetic aperture radar interferometry (InSAR) technique, environmental factors analysis, and risk evaluation are designed here with ALOS PALSAR and Sentinel-1 SAR observations. A retrospect on the ground deformation process indicates that ground deformation has largely decreased by around 51.57% in area but increased on average by around -5.4 mm/year in magnitude over the observation period of Sentinel-1 (30 July 2015 to 22 August 2022), compared to that of ALOS PALSAR (17 January 2007 to 28 October 2010). To better reveal the potential triggering mechanism, environmental factors are also utilized and conjointly analyzed with the ground deformation time series. These analysis results indicate that the ground deformation signals are highly correlated with human industrial activities, such underground mining, and the operation of manual infrastructures (landfill, tailing pond, and so on). In addition, the evaluation demonstrates that the area with potential collapse risk (levels of medium, high, and extremely high) occupies around 8.19 km2, approximately 0.86% of the whole study region. This study sheds a bright light on the safety guarantee for the industrial operation and the ecologically friendly urban development of traditional steel production industrial cities in China.

Iron rescues glucose-mediated photosynthesis repression during lipid accumulation in the green alga Chromochloris zofingiensis

Energy status and nutrients regulate photosynthetic protein expression. The unicellular green alga Chromochloris zofingiensis switches off photosynthesis in the presence of exogenous glucose (+Glc) in a process that depends on hexokinase (HXK1). Here, we show that this response requires that cells lack sufficient iron (−Fe). Cells grown in −Fe+Glc accumulate triacylglycerol (TAG) while losing photosynthesis and thylakoid membranes. However, cells with an iron supplement (+Fe+Glc) maintain photosynthesis and thylakoids while still accumulating TAG. Proteomic analysis shows that known photosynthetic proteins are most depleted in heterotrophy, alongside hundreds of uncharacterized, conserved proteins. Photosynthesis repression is associated with enzyme and transporter regulation that redirects iron resources to (a) respiratory instead of photosynthetic complexes and (b) a ferredoxin-dependent desaturase pathway supporting TAG accumulation rather than thylakoid lipid synthesis. Combining insights from diverse organisms from green algae to vascular plants, we show how iron and trophic constraints on metabolism aid gene discovery for photosynthesis and biofuel production.

Iron-enhanced simulated lunar regolith sintered blocks: Preparation, sintering and mechanical properties

Lunar surface constructions face a hostile service environment, the objective of this study is to develop a lunar base construction material with excellent mechanical properties and superior durability. Based on the abundant iron (Fe) resources on the moon, simulated lunar regolith sintered blocks (CUG-1A) with varying Fe additions (0–10 wt%) were prepared by pressureless sintering, and their sintering characteristics, phase compositions and mechanical performance before and after high-low temperature treatment were studied. The results show that the introduction of the Fe phase noticeably improve the sintering quality and increase the relative density. Furthermore, the Fe phase significantly fortified the sintered blocks, when the Fe addition reached at 10 wt%, the blocks could achieve a compressive strength of 150.92 MPa and a tensile strength of 21.01 MPa. The Fe phase's reinforcement could stem from the mechanisms of promoting sintering, crack deflection and Fe phase bridging. Meanwhile, the high-low temperature treatment does not cause any substantial alterations in the blocks' mechanical strength nor their failure modes. Lastly, large-sized sintered blocks with high dimensional regularity were produced through process optimization, providing a reference for the construction of lunar bases.

A new eco-friendly approach for recovery of iron from copper smelting slag: Using CO2 and Cl2 recycling strategies

Copper smelting slag (CSS) is a by-product of modern copper production. In this study, iron resources were extracted from copper smelting slag using chlorine roasting and magnetic separation techniques for the first time. The results showed that hydrogen could reduce the ferrous chloride on the surface of the pellet to environmentally friendly iron, followed by the complete reduction of the ferrous chloride inside the pellet, thus increasing the metallic iron content in the roasted ore. Finally, the concentrate with a TFe (total iron) mass fraction of 73.41 wt% and iron recovery of 86.50 % was obtained, and XRF, XRD, and XPS analysis showed that iron is mainly enriched in the concentrate, and calcium, silicon, aluminum, and other elements are mainly enriched in the tailing. The innovative addition of recyclable additives in the roasting process not only reduces the production cost but also plays an important role in the current total environmental protection and environmentally sustainable development. Analytical methods such as thermodynamic evaluation, evolutionary trends of key elemental compounds, and molecular simulation were used to fully characterize the complex chemical processes of the chlorination roasting process. This study provides theoretical strategies for the cleaning of CSS and facilitates the industrial implementation of technologies for efficient and economical extraction of iron from CSS.

Recovery of high-quality iron phosphate from acid-leaching tailings of laterite nickel ore

Laterite nickel ore is rich in nickel and iron resources, and the nickel element is extracted in the form of nickel salt. However, the acid-leaching tailings of laterite nickel ore (LTLNO), which contain valuable iron resources, have not been cost-effectively recovered. In this work, we designed a novel method to extract iron from LTLNO and recycle it into high-valuable iron phosphate products using only phosphoric acid and iron powder. We explored the effects of reaction parameters, such as phosphoric acid concentration, iron powder dosage, time, and temperature, on the leaching behavior of key elements. The results showed that the iron leaching rate was as high as 96.54 % when using 3.5 mol/L phosphoric acid with a liquid-to-solid ratio (L/S) of 5 mL/g and an iron powder dosage based on the Fe/Fen+ ratio of 0.5 after 3 h at 25 °C, and a final high-purity FePO4 (99.4 %) was obtained. Kinetic analysis revealed that the leaching reaction was controlled by the diffusion through the neogenetic layer, and the leaching reactions were thermodynamically favorable. This method allows for a simpler and more efficient recovery of iron and the products of higher-value iron phosphate products than other LTLNO recycling technologies. Additionally, it offers a total economic benefit of $134/t for LTLNO treatment, demonstrating great prospects for industrial application.

Selective extraction of germanium from iron-bearing ammonia leaching residue via low-temperature molten NaOH leaching

To address the insolubility of x(SiO2)·GeO2 and y(Fe3O4)·GeO2, this study introduced a two-step leaching (NaOH leaching-NL and low-temperature molten NaOH leaching- LTMNL) method. During the NL process, 51.30 % of germanium (Ge), 84.96 % of aluminum (Al), and 56.45 % of silicon (Si) were leached. Moreover, in the LTMNL process, over 97.43 % of Ge and nearly all amphoteric metals (e.g., Al, Zn, and As) were dissolved under optimized conditions (including a NaNO3-to-ore mass ratio of 0.15, leaching temperature of 170 °C, alkali-to-ore mass ratio of 10, agitation speed of 500 rpm, and reaction time of 2 h). The leachate obtained from the LTMNL process was used as a lixiviant in the NL process to facilitate the recyclable utilization of NaOH and enrich Ge in the leachate solution. This approach resulted in an overall germanium recovery efficiency of 98.72 %. The germanium concentration in the NL leachate exceeded 400 mg/L, thereby facilitating subsequent germanium recovery. Additionally, the LTMNL residue, containing an iron concentration of 52.46 wt%, served as an iron resource. Therefore, the two-step leaching process achieved high germanium recovery and efficient separation of Ge and Fe compared with conventional H2SO4 leaching methods. This indicates that the two-step leaching process is a promising and efficient method for treating germanium-bearing material in the form of x(SiO2)·GeO2 and y(Fe3O4)·GeO2).