Search Results (160)

Wollastonite-1A from Băița Bihor occurs in distal calcic skarns developed in the contact zone of a mainly granodioritic batholith, of Upper Cretaceous age, with Mesozoic limestones and dolostones. Wollastonite generally occurs in the inner part of metasomatic columns, in monomineralic skarns or associated with grossular and molybdenite-2H as ore mineral. The physical properties (i.e., refraction indices α = 1.616, β = 1.629, and γ = 1.631, 2V_α = 39° and density D_m = 2.922(3) g/cm³) are typical for a term close to the stoichiometry, which is confirmed by the chemical analysis. The chemical structural formula of the analyzed wollastonite-1A is (Ca_1.000Mg_0.002Mn_0.001Fe_0.001)(Al_0.004Ti_0.001Si_0.994)O₃, which closely approximates the ideal CaSiO₃. The Gladstone–Dale compatibility indices account for an excellent agreement between physical and chemical data. The mineral can be satisfactorily refined as triclinic, space group $P\overline{1}$, with R₁ = 0.0678 and cell parameters a = 7.9233(3) Å, b = 7.3203(3) Å, c = 7.0651(3) Å, α = 90.053(3)°, β = 95.208(3)°, γ = 103.384(3)°. Both the IR and Raman spectra principally reveal bands related to vibrations of bridged and non-bridged oxygens pertaining to SiO₄ structural tetrahedra. At Băița Bihor, wollastonite-1A is part of the prograde paragenesis, marked by a peak temperature of 550–600 °C. Full article

The Dongqiyishan W-polymetallic deposit is a large porphyry deposit in the Beishan region, Inner Mongolia. Based on cross-cutting relationships of veins and distinct mineral assemblages, the hydrothermal evolution of the Dongqiyishan deposit can be divided into three mineralization stages, with corresponding characteristic alteration types: (1) early W mineralization stage, dominated by potassic–sodic alteration; (2) main W mineralization stage, characterized by extensive phyllic alteration; and (3) post-W-mineralization hydrothermal stage, associated with quartz–fluorite–calcite alteration. This study employs an integrated approach, including molybdenite Re-Os dating, microthermometry of fluid inclusions, and H-O-S isotopic analyses, to investigate the genesis of the deposit. The results show that: (1) the metallogenic age of the deposit is 222.2 ± 1.5 Ma (MSWD = 0.58; Middle Triassic), which was likely caused by the northward subduction of the Paleo-Tethys Ocean; (2) the metallogenic fluids of Stage I (homogenization temperature 350~400 °C, salinity 6.0~8.0 wt.% NaCl eqv.) and Stage II (homogenization temperature 300~350 °C, salinity 4.0~6.0 wt.% NaCl eqv.) are mainly from magmatic water, and Stage III (homogenization temperature 225~275 °C, salinity 4.0~8.0 wt.% NaCl eqv.) has a mixed fluid of magmatic water and meteoric water; (3) the ore-forming materials were mainly derived from magma, which is supported by the S isotopic results (δ³⁴S = −0.5‰~1.6‰, average 0.93‰); (4) mineralization depths calculated through fluid inclusions are 0.52–1.60 km (Stage I), 0.70–1.80 km (Stage II) and 0.10–0.49 km (Stage III); and (5) Stage I W precipitation was likely driven by fluid boiling and water–rock interaction, Stage II W precipitation by water–rock interaction principally, and Stage III fluorite precipitation by water–rock interaction plus fluid cooling. This research provides theoretical guidance for W-polymetallic prospecting in the Beishan of Inner Mongolia. Full article

Constrained by the low grade and poor floatability of the run-of-mine ore, the beneficiation of porphyry-type copper–molybdenum sulfide ores generates large quantities of molybdenum tailings, leading to significant environmental risks and resource losses and necessitating urgent recovery and reutilization. In this study, a representative sample of molybdenum tailings with a Mo grade of 0.354% was investigated to analyze its process mineralogy. The results show that molybdenite predominantly exists as fine, flaky particles intimately intergrown with quartz, pyrite, and aluminosilicate minerals, exhibiting an extremely low degree of liberation and an overall ultrafine particle size. Laboratory flotation tests show that the flotation kinetics conform to a first-order model; however, a considerable amount of molybdenum remains in the tailings, indicating that the mineralization process needs to be intensified. Through structural optimization and confined-space design, a vortex-based mineralization reactor was developed. Computational fluid dynamics simulations demonstrate that the mineralizer can generate flow fields with high turbulence intensity and dissipation rates and can induce high-energy, small-scale micro-vortices. On this basis, a semi-industrial rougher flotation system was established by coupling the developed mineralizer with a flotation column. Under optimized operating conditions, namely a feed pressure of 0.06 MPa and an impeller frequency of 20 Hz, single-stage treatment of the tailings produced molybdenum concentrates with a grade of 1.90% and a recovery of 81.29%, while the Mo grade of the tailings was reduced to 0.08%. The results are markedly superior to those obtained using a conventional laboratory flotation cell, demonstrating a substantial enhancement in mineralization efficiency and molybdenum recovery. The proposed approach, therefore, provides a practical reference for the flotation recovery of molybdenum tailings as well as other micro-fine, low-grade metal tailings. Full article

The Ovor Bayan molybdenum deposit in Mongolia is located within the western segment of the Nukhetdavaa–Erlianhot–Dongwuzhumuqin–Aershan Mo–Pb–Zn–W–Cu–Sn–Cr–Fe metallogenic belt in the Mongolia–Daxing’anling Metallogenic Province. This metallogenic belt lies in the Sino-Mongolian border region, where over ten large-sized deposits have been discovered on the Chinese side in the past two decades. However, the discovered deposits in Mongolia side are relatively small in scale, primarily medium to small-sized, with no large deposits identified to date. Therefore, strengthening research on typical deposits and summarizing metallogenic patterns in this area are the optimal approaches to achieving breakthroughs in prospecting. This study focuses on the Ovor Bayan deposit, a newly identified deposit of molybdenum mineralization within the western segment of the belt. We examine the deposit’s zircon U-Pb geochronology and Re-Os isotopic data. The SHRIMP zircon U–Pb dating of the ore-bearing granite indicates crystallization ages of 183.3 ± 1.9 Ma, which closely align with the mean Re-Os age of 183.1 ± 2.3 MaMa for the Ovor Bayan molybdenum deposit, suggesting an Early Jurassic magmatic event marked by Mo-dominated mineralization coinciding with the extensional tectonic setting following the southeastward subduction-collision of the Mongol–Okhotsk Plate. Regional data indicate that the Nukhetdavaa–Erlian–Dongwuqi–Aershan metallogenic belt experienced concentrated Mo-W mineralization between 240 and 131 Ma. The formation of Mo-dominated deposits, such as Ovor Bayan and Aryn nuur in the western segment of the belt, is at least 50 Ma earlier, which underscores the presence of a significant Mo metallogenic event during this critical post-collision to extensional mineralization period. The molybdenite sample exhibits Re contents ranging from (969.2–1209) × 10⁻⁶, suggesting a mantle-derived source for the molybdenum mineralization. Full article

In this study, column flotation was used to recover high-grade molybdenite (MoS₂) concentrate. Factorial design and statistical analysis were used to evaluate the relationships between the main variables affecting separation efficiency. The main variables were particle size (A), superficial gas velocity (E), depressant dosage (B), superficial wash water velocity (C), and frother concentration (D). MoS₂ grades and recovery of 96.4% and 95.7%, respectively, were obtained under the optimized conditions. ANOVA results indicated that the primary variables affecting the MoS₂ grade were in the following order: E > A > B > C. The interaction terms of AE and CE were identified as critical factors. The main variables affecting the MoS₂ recovery were in the following order: C > B > D > E > A. The interactions of BC, BD, and CD were found to be significant. Furthermore, empirical model equations were derived to predict the grade (G) and recovery (R) based on column flotation variables. The optimal conditions were identified as A: 37.5 µm, B: 200 g/ton, C: 0.1 cm/s, D: 150 ppm, and E: 0.7 cm/s. Full article

The Hadamengou gold deposit, hosted in the Precambrian metamorphic basement, is a super-large gold deposit occurring along the northern margin of the North China Craton. Despite extensive investigation, the genesis of the gold mineralization is poorly understood and remains highly debated. This study integrates a comprehensive dataset, including fluid inclusion microthermometry and C-H-O-S-Pb isotopes, to better constrain the genesis and ore-forming mechanism of the deposit. Hydrothermal mineralization can be divided into pyrite–potassium feldspar–quartz (Stage I), quartz–gold–pyrite–molybdenite (Stage II), quartz–gold–polymetallic sulfide (Stage III), and quartz–carbonate stages (Stage IV). Four types of primary fluid inclusions are identified, including pure CO₂-type, composite CO₂-H₂O-type, aqueous-type, and solid-daughter mineral-bearing-type inclusions. Microthermometric and compositional data reveal that the fluids were mesothermal to hypothermal, H₂O-dominated, and CO₂-rich fluids containing significant N₂ and low-to-moderate salinity, indicative of a magmatic–hydrothermal origin. Fluid inclusion assemblages further imply that the ore-forming fluids underwent fluid immiscibility, causing CO₂ effusion and significant changes in physicochemical conditions that destabilized gold bisulfide complexes. The hydrogen–oxygen isotopic compositions, moreover, support a dominant magmatic water source, with increasing meteoric water input during later stages. The carbon–oxygen isotopes are also consistent with a magmatic carbon source. Sulfur and lead isotopes collectively imply that ore-forming materials were derived from a hybrid crust–mantle magmatic reservoir, with minor contribution from the country rocks. By synthesizing temporal–spatial relationships between magmatic activity and ore formation, and the regional tectonic evolution, we suggest that the Hadamengou is an intrusion-related magmatic–hydrothermal lode gold deposit. It is genetically associated with multi-stage magmatism induced by crust–mantle interaction, which developed within the extensional tectonic regimes. Full article

The Chaijiagou Mo deposit (0.11 Mt Mo @ 0.07%) is located along the northern margin of the North China Craton. This study integrates ore geology, S–Pb–He–Ar–H–O isotopes, and fluid inclusion (FI) analyses to constrain the sources of ore-forming fluids and metals, as well as mineralization mechanisms. Three principal inclusion types were identified: liquid-rich, vapor-rich, and saline FIs. Microthermometry documents a progressive decline in homogenization temperatures and salinities from early to late mineralization stages: Stage 1 (360–450 °C; 5.3–11.3 and 35.4–51.5 wt.% NaCl equation), Stages 2.1–2.2 (320–380 °C and 260–340 °C; 5.4–11.8 and 33.8–44.5 wt.% NaCl equation), and Stage 4 (140–200 °C; 0.4–3.9 wt.% NaCl equation). Noble gas and stable isotope data reveal that the ore-forming fluids were initially dominated by crustally derived magmatic–hydrothermal components with a minor mantle contribution, subsequently experiencing significant meteoric water input. S–Pb isotopic compositions demonstrate a genetic relationship between mineralization and the ore-bearing granite porphyry, indicating a magmatic origin for both sulfur and lead. Fluid–rock interactions and fluid boiling were the dominant controls on molybdenite and chalcopyrite deposition during Stage 2, whereas mixing with meteoric waters triggered galena and sphalerite precipitation in Stage 3. Full article

In this study, the advanced oxidation system of peroxymonosulfate (PMS) was activated by molybdenite supported on biochar (Molybdenite@BC), and the degradation efficiency, influencing factors and degradation mechanism of sulfamethoxazole (SMX) were explored through experiments. Molybdenite@BC, a composite material used in the study, was prepared by pyrolysis at high temperature. The optimum pyrolysis temperature was 700 °C, and the mass ratio of molybdenite to biochar (BC) was 1:3. By changing dosage of Molybdenite@BC, pH value, initial concentration of PMS, and the types and concentration of inorganic anions, the effects of various factors on SMX degradation were systematically studied. The optimum reaction conditions of the Molybdenite@BC/PMS process were as follows: Molybdenite@BC dosage was 100 mg/L, PMS concentration was 0.2 mM, pH value was 6.9 ± 0.2, and initial SMX concentration was 6 mg/L. Under these conditions, the degradation rate of SMX was 97.87% after 60 min and 99.06% after 120 min. The material characterization analysis showed that Molybdenite@BC had a porous structure and rich active sites, which was beneficial to the degradation of pollutants. After the composite material was used, the peaks of MoO₂ and MoS₂ became weaker, which indicated that there was some loss of molybdenum from the material structure. Electron paramagnetic resonance (EPR) and radical quenching experiments revealed that Molybdenite@BC effectively catalyzed PMS to generate various reactive oxygen radicals and non-free radicals, including singlet oxygen (¹O₂), hydroxyl radical (^•OH), sulfate radical (SO₄^•−) and superoxide radical (^•O₂⁻). ¹O₂ played a leading role in the degradation of SMX, while ^•OH and SO₄^•− had little influence. The intermediate products of the degradation of SMX in Molybdenite@BC/PMS system were analyzed by liquid chromatography–tandem mass spectrometry (LC–MS). The results showed that there were nine main intermediate products in the process of degradation, and the overall toxicity tended to decrease during the degradation of SMX. The degradation path analysis showed that with the gradual ring opening and bond breaking of SMX, small molecular compounds were generated, which were finally mineralized into H₂O, CO₂, CO₃²⁻, H₂SO₄ and other substances. The research results confirmed that the Molybdenite@BC/PMS process provided a feasible new method for the degradation of SMX in water. Full article

Molybdenite and chalcopyrite closely coexist and have good natural floatability. During the Cu-Mo separation process, it is necessary to enhance the inhibition of chalcopyrite to reduce its influence on molybdenite. In this paper, a combined inhibitor, sodium thioglycollate (HSCH₂COONa) and sodium sulfide (Na₂S), with a molar ratio of 2:1, was obtained through pure mineral flotation experiments. It could reduce the impact on molybdenite while maintaining a good inhibitory effect on chalcopyrite. In the artificial mixed minerals test, the use of the combined inhibitor (80 mg/L) can achieve good indicators with Mo grade and recovery rate of 54.34% and 88.12%, respectively, and Cu grade of 2.15%. The contact angle test shows that the combined inhibitor can significantly reduce the wettability of the chalcopyrite surface while having a relatively small effect on molybdenite. The infrared spectroscopy and SEM-EDS energy spectrum indicated that the combined inhibitor C = O and S-H groups underwent chemical reactions on the surface of chalcopyrite and squeezed out kerosene on the surface of chalcopyrite. Molecular dynamics simulations indicate that the HS⁻, S²⁻, and HSCH₂COO⁻ components in the combined inhibitor are more likely to act on the surface of chalcopyrite, exerting an enhanced inhibitory effect on chalcopyrite. Full article

The Nakexiuma area in the East Kunlun Orogen Belt hosts two spatially distinct mineralization systems: uranium-molybdenum (U-Mo) in schist and granitoid, and tungsten-molybdenum (W-Mo) in skarn and granitoid. To clarify their genetic relationship, we conducted U-Pb dating and trace element analyses on zircon, garnet, and uraninite. Zircon from granitoids yields a crystallization age of 250 ± 2.3 Ma, followed by W-Mo mineralization at 245 ± 2.1 Ma (garnet) and U-Mo mineralization at 235 ± 9 Ma (uraninite), indicating a prolonged magmatic-hydrothermal history spanning approximately 15 million years. Trace element data reveal a shift in fluid chemistry over time: Skarn garnets show high W contents, suggesting oxidizing, high-temperature fluids; uraninite displays REE depletion and negative Eu anomalies, precipitated from oxidizing fluids encountering a reducing environment. We propose that the W, U, and Mo mineralization in Nakexiuma is the result of this long-lived magmatic-hydrothermal system. The spatial separation of these mineralization systems is attributed to a multi-stage process involving host rock lithology and fluid redox evolution. Early oxidizing fluids from granitoids metasomatized carbonates to form W-Mo mineralization skarn. Later, meteoric water influx increased oxygen fugacity, generating U-rich, highly oxidizing fluids that precipitated uraninite and molybdenite upon interaction with the reducing meta-mafic rocks. These results highlight the roles of lithology and fluid chemistry in controlling spatially separated mineralization within the same system. Furthermore, they expand the Early Mesozoic metallogenic spectrum of the East Kunlun Belt, providing a refined model for polymetallic ore formation in a post-collisional extensional setting. Full article

The Apuseni-Banat-Timok-Srednogorie Metallogenic Belt is one of the most important polymetallic metallogenic belts in the western segment of the Tethys, where numerous porphyry-type, skarn-type, and epithermal deposits are developed. However, scholars have noted a lack of systematic chronological and geochemical studies of andesites within this belt. Furthermore, the metallodynamic mechanisms controlling mineralization—such as oceanic plate exhumation and plate tearing—remain controversial. To complement the available research, this study focuses on andesites from the Čukaru Peki area in Serbia and integrates zircon U-Pb dating, molybdenite Re-Os isotopic analysis, and whole-rock geochemical analysis. The results reveal that plagioclase andesitic breccia and fine-grained plagioclase amphibole andesite were emplaced during the Late Cretaceous. Consistently, the molybdenite isochron age (81.46 ± 0.60 Ma, MSWD = 1.30) constrains the mineralization event to the same period. Both rock types exhibit geochemical signatures typical of island arc volcanic rocks, characterized by high SiO₂ contents and low Al₂O₃, MgO, and TiO₂ contents, as well as pronounced fractionation between light and heavy rare earth elements (LREEs and HREEs). The magma source is the mantle wedge metasomatized by fluid-rich melts derived from the dehydration of the subducted oceanic crust. Additionally, the primary magma produced by partial melting of this metasomatized mantle wedge assimilated and was contaminated by continental crustal material predating the Vardar Ocean’s closure during its ascent. Our findings suggest that the regional andesites are products of the exhumation of the Vardar Ocean. This study aims to provide a theoretical foundation for mineral exploration in the Timok ore cluster and, simultaneously, support the identification of ore prospecting targets in andesite alteration zones. Full article

The Southern Great Xing’an Range (SGXR), an important W–Sn polymetallic metallogenic belt in northern China, hosts multiphase magmatism and has witnessed recent discoveries of multiple tungsten–tin polymetallic deposits. The W–Sn mineralization in this area is intimately associated with Early Cretaceous highly fractionated granites. The Chamuhan deposit, a small-sized W–Mo polymetallic deposit in SGXR, is genetically linked to a concealed fine-grained porphyritic alkali feldspar granite intrusion. In this study, we present the LA-ICP-MS zircon U-Pb ages, whole-rock geochemical, and electron probe microanalysis (EPMA) mineral chemistry to constrain the petrogenesis and metallogenic implications of this granite. Zircon U–Pb dating yields a crystallization age of 141.3 ± 1.2 Ma, consistent with molybdenite Re–Os ages. The granite is characterized by elevated SiO₂ (76.9–79.1 wt%) and total alkalis (7.3–8.5 wt%), and exhibits peraluminous high-K calc-alkaline affinity (A/CNK = 1.37–1.57). Geochemical signatures reveal enrichment in large ion lithophile elements (LILEs, e.g., Rb, Th, U) coupled with depletion in high-field strength elements (HFSEs, e.g., Ba, Sr, P, Eu, Ti, Nb, Ta), and are accompanied by right-sloping REE patterns with LREE enrichment and HREE depletion. EPMA data indicate that the mica in the intrusion is primarily zinnwaldite and Li-rich phengite, whereas the plagioclase occurs as albite. The feldspar thermobarometry yields crystallization temperatures of 689–778 °C and 313 MPa–454 MPa, while the melt H₂O content and oxygen fugacity are 8.61–11.1 wt% and −22.58–−14.48, respectively. These geochemical signatures indicate that the granites are highly fractionated I-type granites with extensive fractional crystallization of various minerals like plagioclase, K-feldspar, and apatite, etc. From the Late Jurassic to the Early Cretaceous, the subduction and rollback of the Paleo-Pacific Ocean plate resulted in extensional tectonic environments in eastern China. Asthenospheric upwelling and lower crustal melting generated parental magmas, wherein progressive fractional crystallization during ascent concentrated ore-forming elements and volatiles within residual melts. This process played a key role in the formation of the Chamuhan deposit, exemplifying the metallogenic potential of highly evolved granitic systems in the SGXR. Full article

Seawater has been widely used in copper–molybdenum flotation plants due to the shortage of fresh water and the high cost of seawater desalination, especially in arid regions. There have been many studies concerning the molybdenite flotation in seawater. Due to the complication of seawater flotation, it is difficult to identify the key factors affecting molybdenite recoveries. It is known that the unique structure of molybdenite plays an important role in molybdenite flotation. The anisotropic property of molybdenite leads to the different surface properties of basal and edge plane surfaces. Electrochemical properties of sulfides have a significant effect on the surface properties which affect the flotation performance. Therefore, it is important to understand the surface electrochemical properties such as surface chemistry, redox processes, and reaction kinetics of molybdenite’s two different surfaces in seawater, and to determine what affects the molybdenite flotation behaviors in seawater. In this study, the surface properties of molybdenite basal and edge plane surfaces in both fresh water and seawater were investigated through various electrochemical techniques. Open circuit potential (OCP) measurement indicated that edge plane surfaces were easier to be oxidized than basal plane surfaces. Cyclic voltammetry (CV) studies showed that the basal plane surfaces were stable with a low electrochemical reactivity, while the edge plane surfaces had relatively high electrochemical reactivity. In addition, the redox property of the molybdenite surface was enhanced in seawater, which is a key to the improvement of fine molybdenite flotation in seawater. Electrochemical impedance spectroscopy (EIS) measurements further confirmed the stability of basal plane surfaces and indicated a greater charge transfer ability of edge plane surfaces in seawater. Different molybdenite particle sizes with different basal and edge ratios were applied in the flotation in both fresh water and seawater; the results illustrated that molybdenite flotation was enhanced in seawater especially to fine particles. The flotation and electrochemical studies reveal that the electrochemical reactivity of edge plane surface plays an important role in molybdenite seawater flotation. Full article

The Xifanping Cu–(Au) deposit, a small-scale porphyry system in the central Jinshajiang–Red River tectonic belt (JSRR), formed in a Cenozoic collisional setting. This study integrates zircon U–Pb geochronology, Lu–Hf isotopes, whole-rock geochemistry, and zircon trace element analyses of ore-bearing and barren porphyries, combined with regional comparisons, to constrain magma sources, metallogenic controls, and genetic processes. Ore-bearing biotite quartz monzonite porphyries were emplaced at 32.15 ± 0.43 Ma and 32.49 ± 0.57 Ma, post-dating barren quartz monzonite porphyry (33.15 ± 0.51 Ma). These ages are consistent with molybdenite Re–Os ages (32.1 ± 1.6 Ma), indicating near-synchronous magmatism and mineralization. Both porphyry types belong to the shoshonitic, peraluminous series, enriched in LILE, depleted in HFSE, enriched in LREE, and lacking significant Eu anomalies. Their εHf (t) values (–2.94 to +3.68) and crustal model ages (TDM2 = 0.88–1.30 Ga) indicate derivation from Neoproterozoic subduction-modified lower crust. Ore-bearing porphyries, however, exhibit higher zircon Ce⁴⁺/Ce³⁺ ratios (average = 584 vs. 228 for barren porphyries) and elevated hydrous mineral contents (>10 vol.% amphibole + biotite), indicating more oxidized and water-rich parental magmas. Compared with large-scale porphyry systems (e.g., Dexing, northern Chile), the absence of adakitic signatures and only moderate oxidation limited the scale of mineralization. Overall, the Xifanping deposit formed through partial melting of Neoproterozoic subduction-modified lower crust in a post-collisional extensional regime: at ~33.2 Ma, melting of metasomatized ancient lower crust generated barren porphyries; at ~32 Ma, further evolution and differentiation of this lower crust magmas led to the extraction and enrichment of ore-forming materials from the thicken lower crust, producing hydrated, oxidized, ore-bearing magmas that intruded at shallow levels to form base and precious metal mineralizations. These results underscore the distinctive metallogenic characteristics of small-scale porphyry systems in collisional settings and provide new insights into how source composition and magma oxidation state constrain mineralization potential. Full article

The selective removal of impurities from molybdenite concentrates is crucial for producing high-purity molybdenum products. In this study, the purification of molybdenite concentrate was investigated using nitric acid as both a leaching medium and oxidizing agent. Leaching experiments were carried out under various conditions of temperature (22–78 °C) and nitric acid concentration (0.12–0.48 M). The results demonstrated that while molybdenite remained mostly undissolved, copper and iron were effectively leached, with near-complete removal at 78 °C in 0.24 M HNO₃ after 6 h. Compared with other acid systems, nitric acid leaching experiments in this study demonstrated higher efficiency and selectivity under relatively moderate conditions of concentration and temperature. Kinetic analyses were performed based on the shrinking core model (SCM) and extended by developing a comprehensive rate equation that incorporates both nitric acid concentration and reactive surface effects. Fitting the developed model to experimental data revealed distinct kinetic regimes below and above 50 °C, suggesting a mechanism shift from surface chemical reaction control to diffusion through an ash layer. The purified molybdenite was characterized by SEM-EDS and ICP-OES, confirming almost complete elimination of Cu and Fe impurities. This work highlights nitric acid as a promising and efficient medium for selective leaching of molybdenite concentrates and provides a comprehensive kinetic model applicable across different leaching conditions. Full article