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Modern trends in technological improvement for producing high-quality rhenium-containing molybdenum concentrates are aimed at developing environmentally friendly solutions com-pared to traditional ones, involving a reduction in consumption or complete replacement of toxic substances and the use of plant reagents and microorganisms and make it possible to eliminate energy-intensive processes of steaming and roasting. It is known that up to 25%–30% of Mo, Cu and Re goes to rough flotation tailings and is lost in wastes. Those losses are a consequence of the ore composition variability, chalcopyrite–molybdenite ratio, an increase in the proportion between primary copper sulfide and finely disseminated molybdenite and the recovery of floating pyrite. High rates of valuable metal recovery into bulk concentrate can be achieved by using new compositions of flotation reagents that selectively change the hydrophobic properties of the target minerals. The application of new reagent compositions, including novel chemicals—dithiopyrylmethane (DTM), composite reagent (CR) and conventional butyl xanthate (ButX)—was theoretically and experimentally substantiated for the effective rhenium extraction in the processing of hard-to-beneficiate complex molybdenum ores. It is identified that DTM forms a complex DTM–Re compound and chemically adsorbed on rhenium-containing molybdenite providing an increase in Re recovery into the bulk Cu–Mo–Re concentrate by 17%, reducing by two times the loss of rhenium with flotation tailings, and the subsequent 97.6% Re extraction of the molybdenum concentrate by autoclave leaching. [ABSTRACT FROM AUTHOR]

The Balka Zolota gold-molybdenum deposit is located in the central part of the Solone ore field in the southern part of the Sura greenstone structure of the Middle Dnipro megablock of the Ukrainian Shield. Molybdenum mineralization is confined to the eastern flank of the deposit and is termed as the Solone occurrence. Main questions are address in this study of thе occurrence: i) the discovery and study of the deposit, ii) the composition of wall rock complex, iii) the structural position and localization of molybdenum mineralization, iv) the morphology of orebearing zones and ore bodies, (v) the composition of the ores, (vi) the ore mineral associations and the sequence of their formation, (vii) morphological features of molybdenite and (viii) a general analysis on the genesis of molybdenum mineralization. Mining of molybdenum ore of Balka Zolota deposit is possible in the case of output, first of all, gold ores. It can be realized more realistically after the start of mining operations within the Serhiivka gold-molybdenum deposit. Further geological exploration focusing on the Balka Zolota deposit is needed to assess the resources and reserves potential of the gold and molybdenum mineralization, especially on the eastern flank of the deposit. [ABSTRACT FROM AUTHOR]

Modern trends in technological improvement for producing high-quality rhenium-containing molybdenum concentrates are aimed at developing environmentally friendly solutions com-pared to traditional ones, involving a reduction in consumption or complete replacement of toxic substances and the use of plant reagents and microorganisms and make it possible to eliminate energy-intensive processes of steaming and roasting. It is known that up to 25%–30% of Mo, Cu and Re goes to rough flotation tailings and is lost in wastes. Those losses are a consequence of the ore composition variability, chalcopyrite–molybdenite ratio, an increase in the proportion between primary copper sulfide and finely disseminated molybdenite and the recovery of floating pyrite. High rates of valuable metal recovery into bulk concentrate can be achieved by using new compositions of flotation reagents that selectively change the hydrophobic properties of the target minerals. The application of new reagent compositions, including novel chemicals—dithiopyrylmethane (DTM), composite reagent (CR) and conventional butyl xanthate (ButX)—was theoretically and experimentally substantiated for the effective rhenium extraction in the processing of hard-to-beneficiate complex molybdenum ores. It is identified that DTM forms a complex DTM–Re compound and chemically adsorbed on rhenium-containing molybdenite providing an increase in Re recovery into the bulk Cu–Mo–Re concentrate by 17%, reducing by two times the loss of rhenium with flotation tailings, and the subsequent 97.6% Re extraction of the molybdenum concentrate by autoclave leaching.

The article is devoted to molybdenum mineralization of the Eastern flank of Au-Mo Serhiivka deposit, located in the Middle Dnipro megablock of the Ukrainian Shield (USh). The generalized description of mineralization is performed on such important questions: discovery and exploration history, structure and composition of the host rocks, metamorphic and metasomatic alteration of rocks, structural position and localization conditions of molybdenum mineralization, ore composition, description of major ore minerals, morphology of mineralization and the most widespread views about its genesis. Molybdenum ores were discovered and named East-Serhiivka occurrence for the first time in 1974, before the discovery of gold mineralization, which occurred in 1985. Serhiivka deposit consists of two Mesoarchaean volcanic-plutonic associations (VPA) of different composition: the early mafic and the late felsic. The Eastern flank of the deposit, where the molybdenum mineralization is concentrated, is a structural knot similar to the lying letter “T”. It is formed by complex joint of the sub-latitudinal Serhiivka and sub-meridional Solone subvolcanic bodies and the East-Serhiivka massif of plagiogranitoids of the late VPA, which intrude basic rocks of early VPA. Molybdenum mineralization is localized in linearly elongated zones with a chaotic network of thin quartz, carbonate-quartz veinlets and poor (2–5 %) sulfide impregnation, including molybdenite. About 20 vein-impregnated ore zones have been recovered with up to 100–150 m thickness and 0,01 to 0,3 %, sometimes more than 1 % average molybdenum grade. The ores are subdivided into two major mineral types: 1) quartz-molybdenite; 2) quartz-sulfide-gold-molybdenite. The main components of ores molybdenite and native gold are associated with pyrite, chalcopyrite, magnetite, occasionally – pyrrhotite, arsenopyrite, scheelite, bismuth telluride, silver and others. Typical non-metallic minerals are quartz, carbonate, feldspar, chlorite, amphibole, biotite, sericite. It is supposed hydrothermal-metamorphogenic genesis of molybdenum (and gold) ores. Molybdenite and gold are rarely detected in the same intersections, which indicates separate genesis of these minerals. According to the accepted classification molybdenum mineralization is systemized as linear stockwork. Molybdenum ores of Serhiivka deposit are mostly considered as independent, separate from gold mineralization, potentially workable mine. It is the most prospective one in the Middle Dnipro region, USh and Ukraine in general. We suggest a comprehensive approach to studying, resource and reserves evaluation of Serhiivka deposit, taking into account the potential of both molybdenum and gold mineralization, as well as concentrations of rhenium and osmium in molybdenite. Geological exploration on the base of this approach will increase investment prospects of Serhiivka gold-molybdenum deposit.

Highlights • Pyrogallic acid exhibit selective depression effect on bismuthinite flotation. • Pyrogallic acid expanded the difference in flotation rate of both minerals. • Pyrogallic acid has a destabilizing effect on the froth phase. Abstract Molybdenum ore flotation techniques are constantly challenged by the emergence of complex sulfide minerals, such as bismuthinite, in the mineral processing industry. Conventional flotation depressants, such as sodium sulfide, used in Mo–Bi-containing ore flotation require high dosages, which leads to high cost and low selectivity. Therefore, in this study, pyrogallic acid (PA), a widely distributed organic source, is tested as an alternative depressant to selectively depress bismuthinite in Mo–Bi sulfide ores from Shizhuyuan. Results show that PA has a minimal effect on molybdenite recovery; by contrast, PA has a high depressing effect on bismuthinite amelioration. At 500 g/t PA, molybdenum recovery slightly decreases by 2 percentage points, and bismuth content in molybdenum concentrate sharply declines by 34 percentage points, with respect to samples floated without PA. Batch flotation tests demonstrate that PA addition affects froth stability, as indicated by the variations of solid and water recoveries. The superior selectivity of molybdenite over bismuthinite is promoted by increasing the PA dosage. On the basis of these findings, PA is a feasible option and thus can be used as a depressant for bismuthinite in the flotation of sulfide minerals. [ABSTRACT FROM AUTHOR]

Over five hundred W-Mo skarns have been reported in the Neoproterozoic Seridó belt in the northeastern Brazil. The origin of these mineralizations has been attributed to metasomatic reactions occuring after the infiltration of hydrothermal fluids that are mostly derived from the plutonic magmatic activity that ranged between approximately 600 and 525 Ma. Here we date molybdenite using N-TIMS on Re-Os analysis of three major scheelite deposits (Brejuí, Bonfim and Bodó) hosted in the skarn horizons of the metasedimentary sequence. Molybdenite is an integral part of the mineralizations that include scheelite in skarns and, in the Bonfim deposit, gold concentrate in late brittle faults. The Re-Os ages are 554 ± 2 Ma (Brejuí), 524 ± 2 Ma (Bonfim) and 510 ± 2 Ma (Bodó). The age of the Brejuí molybdenite, however, appears to be anomalous based on the local geology of the deposit, which is located next to the contact of a batholith dated ca. 575 Ma. In turn, the Bonfim molybdenite yields similar ages in replicated samples with variable high Re contents. New U-Pb SHRIMP ages of four biotite (leuco)granite plutons vary from 577 ± 5 Ma to 526 ± 8 Ma, which overlap with molybdenite crystallization. These results indicate a close connection between the W-Mo mineralizations and the plutonic activity that intruded the belt after the peak HT/LP metamorphism. The latest pulses of felsic magmatism, which were contemporaneous with the emplacement of Be-Ta-Nb-Li pegmatites, therefore constitute a potential guide in the Seridó belt for prospective W-Mo deposits. [ABSTRACT FROM AUTHOR]

The Yinyan Sn deposit, one of the three typical porphyry Sn deposits in China, is located in the western Guangdong province of the Cathaysia Block. Rhenium and osmium isotopes of molybdenites from the Yinyan deposit were first used to constrain the age of mineralization. Rhenium concentrations in molybdenite samples range from 0.13 to 1.3 µg g−1, indicating a crustal source for the ore-forming materials. The Re-Os dating yield model ages ranging from 78.1 to 79.52 Ma, with an average of 78.65 ± 0.98 Ma, and give an isochron age of 78.8 ± 2.6 Ma. Evidently, isochron age is consistent with model ages in the error within the allowable range, so we can constrain the precise age of Yinyan Sn deposit at the Late Cretaceous. Based on the geological history and spatial-temporal distribution of the Sn deposits, it is proposed that the formation of Sn deposits in the Cathaysia Block were related to lithospheric extension that are associated with a change in the polarity of the subduction of the Paleo-Pacific Plate from oblique subduction to parallel the eastern margin of the Eurasian Plate after 135 Ma. [ABSTRACT FROM AUTHOR]

The recently discovered Baizhangyan skarn-porphyry type W- Mo deposit in southern Anhui Province in SE China occurs near the Middle- Lower Yangtze Valley polymetallic metallogenic belt. The deposit is closely temporally-spatially associated with the Mesozoic Qingyang granitic complex composed of granodiorite, monzonitic granite, and alkaline granite. Orebodies of the deposit occur as horizons, veins, and lenses within the limestones of Sinian Lantian Formation contacting with buried fine-grained granite, and diorite dykes. There are two types of W mineralization: major skarn W- Mo mineralization and minor granite-hosted disseminated Mo mineralization. Among skarn mineralization, mineral assemblages and cross-cutting relationships within both skarn ores and intrusions reveal two distinct periods of mineralization, i.e. the first W- Au period related to the intrusion of diorite dykes, and the subsequent W- Mo period related to the intrusion of the fine-grained granite. In this paper, we report new zircon U- Pb and molybdenite Re- Os ages with the aim of constraining the relationships among the monzonitic granite, fine-grained granite, diorite dykes, and W mineralization. Zircons of the monzonitic granite, the fine-grained granite, and diorite dykes yield weighted mean U- Pb ages of 129.0 ± 1.2 Ma, 135.34 ± 0.92 Ma and 145.3 ± 1.7 Ma, respectively. Ten molybdenite Re- Os age determinations yield an isochron age of 136.9 ± 4.5 Ma and a weighted mean age of 135.0 ± 1.2 Ma. The molybdenites have δ34 S values of 3.6‰-6.6‰ and their Re contents ranging from 7.23 ppm to 15.23 ppm. A second group of two molybdenite samples yield ages of 143.8 ± 2.1 and 146.3 ± 2.0 Ma, containing Re concentrations of 50.5-50.9 ppm, and with δ34S values of 1.6‰-4.8‰. The molybdenites from these two distinct groups of samples contain moderate concentrations of Re (7.23-50.48 ppm), suggesting that metals within the deposit have a mixed crust-mantle provenance. Field observation and new age and isotope data obtained in this study indicate that the first diorite dyke-related skarn W- Au mineralization took place in the Early Cretaceous peaking at 143.0-146.3 Ma, and was associated with a mixed crust-mantle system. The second fine-grained granite-related skarn W- Mo mineralization took place a little later at 135.0-136.9 Ma, and was crust-dominated. The fine-grained granite was not formed by fractionation of the Qingyang monzonitic granite. This finding suggests that the first period of skarn W- Au mineralization in the Baizhangyan deposit resulted from interaction between basaltic magmas derived from the upper lithospheric mantle and crustal material at 143.0-146.3 and the subsequent period of W- Mo mineralization derived from the crust at 135.0-136.9 Ma. [ABSTRACT FROM AUTHOR]

In an effort to contribute to the discussion concerning the age of rocks of the Moldanubian Variegated Group, we have undertaken Re-Os dating of molybdenite of banded carbonatite-like marbles (CLM) from the graphite mine Václav at Bližná (Southern Bohemia), which belong to the metamorphic sequence of this group. The Re-Os model ages for the molybdenites range between 493 and 497 Ma and apparently correspond to the early stages of metamorphism connected with pre-Variscan rift-related tectono-metamorphic events, which affected and recrystallized sedimentary CLM material rich in Mo-Th-Nb-REE. The molybdenite bearing carbonatite like marbles situated in the footwall of Bližná graphite mine have been interpreted as carbonates with a large share of volcano-detritic material derived from contemporaneous primitive alkaline (carbonatite-like) volcanism deposited in a shallow marine lagoonal environment. There is no geological evidence for the participation of fluids mobilized from host rocks in the formation of the CLM. Because the Re-Os chronometer in molybdenite is demonstrably stable through later Variscan facies metamorphism, the molybdenite chronometer has not been affected by subsequent thermal overprints associated with the Variscan orogeny. [ABSTRACT FROM AUTHOR]

The Dabie orogen is among the most famous continent–continent collisional orogenic belts in the world, and is characterized by intensive post-collisional extension, magmatism and Mo mineralization. However, the genetic links between the mineralization and the geodynamic evolution of the orogen remain unresolved. In this paper, the Yaochong Mo deposit and its associated granitic stocks were investigated to elucidate this issue. Our new zircon U–Pb ages yielded an Early Cretaceous age (133.3 ± 1.3 Ma) for the Yaochong granite, and our molybdenite Re–Os dating gave a similar age (135 ± 1 Ma) for the Mo deposit. The Yaochong stock is characterized by high silica and alkali but low Mg, Fe and Ca. It is enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs: Rb, K, Th and U), but strongly depleted in heavy REEs, and high field strength elements (HFSEs: Nb, Ta, Ti and Y). The Yaochong granite has initial 87 Sr/ 86 Sr ratios of 0.7087–0.7096, and Pb isotopic ratios of ( 206 Pb/ 204 Pb) i = 16.599–16.704, ( 207 Pb/ 204 Pb) i = 15.170–15.618 and ( 208 Pb/ 204 Pb) i = 36.376–38.248. The granite has ε Nd ( t ) of −18.0 to −16.3 and ε Hf ( t ) values of −26.5 to −20.0. All these data indicate that the Yaochong granite is a high-K calc-alkaline fractionated I-type granite, and may have originated from partial melting of the thickened Yangtze continental crust. The Mo ores also show low radiogenic Pb isotopes similar to the Yaochong stock. Medium Re content in molybdenite (21.8–74.8 ppm) also suggests that the ore-forming materials were derived from the thickened lower crust with possibly minor mixing with the mantle. Similar to the Eastern Dabie orogen, the thickened crust beneath the Western Dabie orogen may also have experienced tectonic collapse, which may have exerted fundamental geodynamic controls on the two-stage Mo mineralization in the region. [ABSTRACT FROM AUTHOR]

The Gaogangshan Mo deposit, located in the northern part of the Lesser Xing'an Range (the eastern part of the Xing'an- Mongolia Orogenic Belt), is one of the newly discovered Mo deposits in northeast China. Ore bodies occur in the granite and are generally in vein and stockwork forms. Major metallic minerals in the ore include pyrite and molybdenite. The styles of mineralization are disseminated, veinlet-disseminated, and veinlet. The major types of wall-rock alteration are silicification-potassic alteration, phyllic alteration and propylitization. Fluid inclusion analyses indicate that the ore-forming fluid during the major mineralization stage is an H2O- NaCl- CO2 system, with wide homogenization temperature and salinity ranges. The abundant CO2-rich and coexisting halite-bearing fluid inclusion assemblages in the main stage of mineralization highlight the significance of intensive fluid boiling for porphyry Mo mineralization. Comprehensive study of the ore-forming conditions, geological features of the deposit, micro-thermometric analysis of fluid inclusions and comparison of the Gaogangshan deposit with other typical porphyry deposits leads to the conclusion that the deposit is a porphyry type. We obtained a weighted mean age of the molybdenite deposit at Gaogangshan of 250.7 ± 1.8 Ma. The isotopic dating results indicate that the Gaogangshan deposit was formed in the Permo-Triassic, which is the earliest Mo-only deposit in northeast China. The formation of the Gaogangshan Mo deposit may be related to the extension and break-up of the Songnen Block and Jiamusi Block in the Permo- Triassic. [ABSTRACT FROM AUTHOR]

The main problem in the flotation of Cu-Mo sulfide ores in seawater is poor floatability of molybdenite at pH>9.5. Froth stability plays a very important role in determining concentrate grade and recovery in flotation operations and in this paper both floatability and frothability have been tested. The frothability have been studied by measuring froth equilibrium layer thickness in a modified laboratory flotation cell. Two chemical aspects of seawater need to be considered: the content of NaCl (around 87% of salinity), and the concentration of secondary ions (around 13%) (sulfate, magnesium, calcium, bicarbonate ions, etc.). Seawater, NaCl solutions, and seawater's ions were found to depress frothability. The effect of pH on frothability over the pH range from 9.5 to 11, which is very strong in freshwater, becomes negligible in seawater and the tested electrolyte solutions. The analysis of the relationship between the mechanisms of molybdenite depression and the loss of frothability in seawater implies that the effects of the studied ions on molybdenite floatability and on pulp frothability are different. While depression of molybdenite floatability could be tracked down to magnesium hydroxide precipitation as a main culprit, the depression of frothability is a much more complicated issue. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, three flotation approaches, bulk flotation followed by separation, selective Cu flotation followed by bulk flotation and then separation, and preferential Mo flotation followed by Cu flotation, were investigated to concentrate molybdenite from Dexing (Jiangxi Province, China) porphyry Cu–Mo ores. The bench-scale flotation results demonstrated that compared to other two flotation approaches, the preferential Mo flotation approach using a new non-thiol collector obtained a high recovery of molybdenite in a molybdenum circuit, while the tailing of molybdenum circuit was treated by a copper flotation circuit to obtain a high recovery of other co-present metal values. The industrial flotation tests indicated that compared to the bulk flotation approach, the preferential Mo flotation approach achieved an excellent cleaner concentrate containing 0.655% Mo with 88.49% Mo recovery, and increased Mo recovery and grade over 34.0% and 0.4% in the molybdenum circuit, respectively. For being uncontaminated with thiol collectors, this cleaner concentrate was readily treated to perform the Mo/Cu flotation separation which returned a superior Mo concentrate containing 48.83% Mo with 90.60% Mo operation recovery as well as saved about 1/2 Na2S consumption. [Copyright &y& Elsevier]

Abstract: With increasing molybdenum ore mining, the difficult to treat ores, i.e., lower-grade and fine-disseminated ores have gradually increased in importance. Kerosene was widely used as the conventional collector of molybdenum flotation all along, but it does not adapt well to the flotation of molybdenite in difficult to treat ores. Meanwhile, kerosene has been cancelled from the manufacture catalogue in China, which makes large refineries no longer produce it, and in turn makes it difficult for a molybdenum flotation plant to purchase kerosene and makes it even harder for kerosene to keep a stable composition. Therefore, many molybdenum flotation plants began to apply diesel oil instead of kerosene as collector for molybdenite. However, the flotation results reveal that diesel oil from different manufacturers or being of different specifications from the same manufacturers has a different effect on the flotation of molybdenite, and pulp temperature has an obvious effect on the flotation efficiency of diesel oil. In pulp temperatures ranging from 10 to 30°C, the flotation recovery of molybdenite increases with increasing high-boiling component in diesel oil. When pulp temperature is below 10°C, the flotation recovery of molybdenite is related to the dispersibility of diesel oil, i.e., the proportion of high-boiling and low-boiling component in diesel oil. Therefore, a molybdenum flotation plant should not blindly apply diesel oil instead of kerosene as the collector for molybdenite, but should select diesel oil that is suitable for the properties of its ore. This technical note is helpful to better select the proper collector for a molybdenum flotation plant. [Copyright &y& Elsevier]

An attempt has been made in this investigation to develop a chemical method for treating molybdenite concentrate from Qattar (Eastern Desert, Egypt). The core of the process lies in replacement of pyrometallurgical processing with a hydrometallurgical method using oxygenated nitric acid leaching under atmospheric and oxygen pressure. The effects of temperature, acid concentration, partial pressure as well as the kinetics of leaching process were studied. [ABSTRACT FROM AUTHOR]

A small occurrence of molybdenite (MoS2) mineralisation has been discovered in the weakly A-type Pomona Island Granite on the shorelines of Lake Manapouri in eastern Fiordland. The disseminated appearance of molybdenite and the absence of quartz veins indicates that mineralisation is probably the product of magmatic and/or hydrothermal activity related to pluton crystallisation at c. 157 Ma, and not younger (c.128-116 Ma) shear zone-related mesothermal mineralisation as has been recently described from the Murchison Mountains to the north and Stewart Island to the south. Although apparently not of economic grade, the Pomona Island Granite locality is regionally important because it is the first direct pluton-related Mo-mineralisation event to be recognised in eastern Fiordland. This occurrence adds to the growing number and known styles of base metal occurrences within the Jurassic-Cretaceous magmatic arc (Outboard Median Batholith) that formed on or near the New Zealand Gondwana margin. Furthermore, the wide distribution of essentially uninvestigated A-type granites in the Outboard Median Batholith means that there may be further Mo-mineralised localities awaiting discovery. [ABSTRACT FROM AUTHOR]

The Baishiding molybdenum deposit is located in the Central-Middle Guangxi depression zone of the South China Caledonian fold zone. Orebodies occur as quartz-molybdenite veins within the Guiling monzonite pluton and arkosic quartz sandstone of Zhengyuanling Group in the northeastern Guangxi. They are NEE-trending with a dip angle of 75–80°. Zircon SHRIMP U-Pb geochronologic analyses of the Guiling monzonite show age of 424.4 ± 5.6 Ma. It indicates that the Guiling monzonite was emplaced in Silurian. The ore minerals in quartz-molybdenite veins contain molybdenite, pyrite, chalcopyrite and scheelite. Six molybdenite samples yield Re-Os ages between 433.3 ± 6.3 Ma and 417.2 ± 5.7 Ma, with a weighted mean age of 424.6 ± 5.7 Ma, which agrees with the zircon age of the Guiling monzonite pluton. It suggests that the deposit was formed in the Silurian, not the Jurassic as previously thought. The Baishiding deposit is the only Silurian molybdenum deposit so far recognized in the South China. It was probably formed in a crustal shortening setting along the continental margin in the Silurian. [ABSTRACT FROM AUTHOR]

The Xiaodonggou porphyry Mo deposit is located in the Mesozoic calc-alkaline Xiaodonggou granitoid within a Palaeozoic fold zone of northern China. The mineralization mainly occurred in an area of 0.54 km2 at the south-eastern part of the Xiaodonggou granitoid. The mineralization includes disseminated molybdenite, pyrite, chalcopyrite, magnetite and pyrrhotite and stockwork quartz-sulfide veins. A molybdenite-rich inner core is surrounded by a concentric zone of the sulfide mineral assemblage of pyrite, galena and sphalerite. Intense potassic alteration is overprinted by sericitization and silicification in the mineralized zone. SHRIMP U-Pb data of zircon indicate that the granitoid crystallized at 142 ± 2 Ma (2σ). Re–Os age dating for six molybdenite samples from underground galleries of the deposit constrains the age of porphyry-style Mo mineralization to be 138.1 ± 2.8 Ma (2σ). These data suggest that porphyry-style mineralization was associated with the Xiaodonggou granitoid intrusion and support an Early Cretaceous porphyry-type metallogenic epoch along the northern margin of North China Craton. [ABSTRACT FROM AUTHOR]

Abstract: The Lanjiagou Mo deposit is located in the eastern part of the North China Craton. Rhenium and osmium isotopes in molybdenites from the Lanjiagou porphyry Mo deposit have been used to determine the timing of mineralization. Molybdenite was analyzed mainly from granite porphyry, which is characterized by moderate to strong silicification. Rhenium concentrations in molybdenite samples are between 33 and 48 µg/g. Analysis of eleven molybdenite samples yields an isochron age of 181.6±6.5 Ma (2σ). Based on the geological history and spatio-temporal distribution of the granitoids, it is proposed that the Mo deposits in the eastern part of the North China Craton were related to the subduction of the Paleo-Pacific plate during Jurassic time. [Copyright &y& Elsevier]

The oxidation mechanism of a commercial molybdenum concentrate was investigated up to 650 °C using thermal analysis. Upon introduction of air, the molybdenite concentrate started to lose mass due to the oxidation of MoS2 to form molybdenum oxide and SO2. After a rapid mass loss, this was followed by a period of mass gain due to the oxidation of MoO2 to MoO3. The solid-state reaction between MoS2 and MoO3 to form MoO2 was also found to take place. Initially, as air is introduced, the rate is controlled by gas-phase diffusion of oxygen to the reaction surface. With time, as the surfaces of the MoS2 particles become oxidized and the rates start to slow, MoO3 starts to form. This generally leads to a mass gain as well as a slow down in oxidation rate due to the formation of a fairly dense MoO3 product layer. The timing of the various reactions was very dependent on the actual experimental conditions such as sample mass, gas flow rate, and heating rates. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2), a layered transition-metal dichalcogenide, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and geotechnical engineering. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. In addition, understanding the insertion of metals into molybdenite and evaluation of charge-transfer mechanism and dynamics is important to utilize these minerals in technological applications. Furthermore, a detailed investigation of thermal oxidation behavior and metalinsertion will provide a basis to further explore and model the mechanism of adsorption of metal ions onto geomedia. The present work was performed to understand thermal oxidation and metal-insertion processes of molybdenite surfaces. The analysis was performed using atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). Structural studies using SEM and TEM indicate the local-disordering of the structure as a result of charge-transfer process between the inserted lithium and the molybdenite layer. Selected area electron diffraction measurements indicate the large variations in the diffusivity of lithium confirming that the charge-transfer is different along and perpendicular to the layers in molybdenite. Thermal heating of molybenite surface in air at 400°C induces surface oxidation, which is slow during the first hour of heating and then increases significantly. The SEM results indicate that the crystals formed on the molybdenite surface as a result of thermal oxidation exhibit regular thin-elongated shape. The average size and density of the crystals on the surface is dependent on the time of annealing; smaller size and high density during the first one-hour and significant increase in size associated with a decrease in density with further annealing. [ABSTRACT FROM AUTHOR]

Abstract: Evaluation of reagents to be the potential frothers for copper-molybdenite sulfide mineral flotation is systematically studied. A frother characterization methodology including, the parameters of frothing system, namely, initial dynamic frothability index (IDFI) and initial dynamic froth collapse rate (IDCR) are used in the analysis of dynamic frothability of reagent and in selection of potential frothers. Flotation tests using the reagents as frothers for copper-molybdenite sulfide mineral are conducted to determine the metallurgical performance of these potential frothers. The metallurgical performance of the flotation is also used to confirm the potential frothers selected by using the parameters of the frothing system. IDFI and IDCR can also be used in the formulation of frother mixtures from the reagents, to meet a certain desired frother property. [Copyright &y& Elsevier]

Abstract: Bioleaching of Sarcheshmeh (Iran) molybdenite concentrate using a native strain of Acidithiobacillus ferrooxidans for extraction of rhenium was evaluated. Bioleaching tests showed that rhenium was extracted from the molybdenite concentrate, but rhenium extraction was low. Maximum rhenium extraction was 7.3%, while molybdenum extraction was 0.54%. The native strain of the Acidithiobacillus ferrooxidans had been able to grow on media that contain up to 250 mg/L molybdenum by the addition of pyrite as an energy source, approximately three times more molybdenum than those that had been reported for Acidithiobacillus ferrooxidans. [Copyright &y& Elsevier]

Focuses on the mineral molybdenite, the principal source of the element molybdenum. Discovery of molybdenite in the tungsten veins in the Caldbeck Fells of Cumbria; Only significant host mineral of rhenium (Re); Genetic relationship with the structure of molybdenite and corresponding Re values.

Fluorine-rich hydrothermal mineral assemblages developed at Henderson, Colorado, as 12 rhyolitic stocks of Oligocene age were emplaced, crystallized, and cooled inside a much larger and slightly older, rhyolitic intrusion, forming a Climax- type molybdenum deposit. The stocks are grouped into three intrusive centers, and the mineral assemblages, including ore minerals, are grouped according to their temperatures of formation as either high-, moderately high, moderate-, or low-temperature assemblages. The latter three groups are termed lower temperature assemblages, which are subdivided into two suites on the basis of position: above intrusive centers and on the flanks of the Seriate center. Integration of the mineralogy, sequence, and spatial positions of mineral assemblages defines the geochemical evolution of hydrothermal fluids, places qualitative constraints on mass transfer, and provides insight into the development of the geochemical halos that are used in exploration for porphyry orebodies. A reconnaissance fluid inclusion study targeted the lower temperature assemblages, and a geologic assessment of results indicates that we were unable to identify fluid inclusions from several assemblages, After pooling meaningful results, the ranges of temperatures of formation for each group of lower temperature assemblages are moderately high, 600° to 460°C: moderate, 530° to 310°C; and low, 390° to 200°C, with significant differences in salinity between the two suites of assemblages, The suite formed above intrusive centers was deposited by more saline fluids (salinity commonly 28-65 wt % NaCl ± KCl equiv) than the suite formed on the flanks of the Seriate center (mostly <29 wt % NaC1 + KCl equiv). The lower temperature assemblages described here do not overlap in space with higher level propylitic alteration, but fluid inclusions in one sample of propylitized rock indicate temperatures of 320° to... [ABSTRACT FROM AUTHOR]

At Henderson, Colorado, 12 rhyolitic stocks of Oligocene age crystallized in three intrusive centers whose tops are 1 km below the surface of Red Mountain: Henderson (oldest), Seriate, and Vasquez (deepest and youngest). A variety of fluorine-rich hydrothermal mineral assemblages are grouped according to their temperatures of formation, either high-, moderately high, moderate-, or low-temperature (the latter three groups are termed lower temperature assemblages). The groupings were based on relative age relationships in areas free of cyclical events, and absolute temperature estimates based on fluid inclusion study later were made for many mineral assemblages, as detailed in a companion paper. Numerous crosscutting contacts of individual stocks combined with limits of associated high-temperature assemblages can be interpreted as spatially extensive time lines, thereby enabling temporal correlation of spatially separated events. High-temperature silicic (quartz-fluorite) and intense potassic (quartz-K-feldspar-molybdenite) assemblages developed in numerous cycles, each corresponding to emplacement of a stock and deposition of molybdenite. Molybdenite occurs without pyrite mostly in the high-temperature assemblages. In contrast, lower temperature assemblages broadly envelop intrusive centers, rather than single stocks. Some of the moderately high temperature, less intense potassic assemblages (including mottled K-feldspar-quartz and magnetite-K-feldspar) also formed during multiple cycles. Moderate-temperature sericitic assemblages (including topaz with pyrite or magnetite and sericite with pyrite or magnetite) only locally exhibit evidence for multiple cycles, and low-temperature intermediate argillic assemblages (pyrite-day and several assemblages containing base metal sulfides, F-bearing, Mn-rich garnet, and rhodochrosite) were deposited in only a single event. These lower temperature assemblages terminate 700 m below the present surface... [ABSTRACT FROM AUTHOR]

The article offers information on a research of porphyry mineralization conducted in the Gangdese Orogenic Belt in Tibet, China. Topics discussed include the granitoids derived from continental crustal sources for porphyry Molybdenum mineralization, grantinoids derived from mantle for porphyry copper mineralization, and deposits of molybdenite derived from mantle having high contents of Rhenium.

The article presents a study to determine ages of rhenium (Re)-osmium (Os) and uranium-lead of the Sifangdianzi molybdenite (Mo) deposit in Central Jilin Province, northeast China. Topics discussed include gangue minerals present in Sifangdianzi Mo like quartz, feldspar and biotite, development of wall-rock alteration including silicification, kaolinization and chloritization, and zircons from monzogranite of the Sifangdianzi Mo.

The article discusses the research study conducted to examine the geological characteristics and Molybdenite (Mo) Rhenium (Re)-Osmium (Os) isotopic dating of the Doupo Mo Deposit, Dabie Orogen, Eastern China. It reveals the hydrothermal alteration types of wall rocks and main ore-forming types including disseminated, veinlet, stockwork and laminated molybdenite mineralizations. It also mentions the use of main metallogenic stage of molybdenite samples in Re-Os isotopic dating.

The article focuses on the research "Porphyry Mo Mineralization in Different Tectonic Setting: Indication from Fluid Inclusions in Shapinggou and Zhilingtou Mo Deposits, China" by Ni Pei. It mentions the stages of hydrothermal alteration and mineralization at Shapinggou which includes ore-barren quartz veins with silicification, quartz-molybdenite veins, and quartz-polymetallic sulfide veins. It presents ore fluid features and tectonic setting of the Zhilingtou deposit.

The article offers information on the research "Molybdenite Re-Os Isochron Age of the Huoshenmiao Mo Deposit in Luanchuan Henan Province, China and Its Geological Implications" by Wang Sai and colleagues. It mentions the determination of the mineralization age and clarification of the relationships with Nannihu-Sandaozhuang and Shangfanggou molybdenum deposits. Topics discussed include tonalite and granite porphyry, polymetallic pyrite deposits and silver-lead-zinc deposits, and intrusion.

The article offers information on the research "Geology, Geochemistry, and Genesis of the Tongcun Porphyry Mo (Cu) Deposit, NW Zhejiang Province, China" by Tang Yanwen and colleagues. Topics discussed include granodiorite porphyry, molybdenum-copper mineralization, and mineral assemblages and fluid inclusion. Also mentioned are ore minerals including molybdenite, chalcopyrite, and pyrite; microthermometry and isotopic analysis; and ore genesis.

The article offers information on the research "Metallogeny Study of Molybdenum Deposits in Jiaodong Mesozoic Metallogenic Province, China" by Liu Zhenjiang and colleagues. Topics include metallogeny relationship between the coexistence of gold and molybdenum deposits in the province, mineralization of molybdenum in the Early Yanshanian and the Late Yanshanian, and Molybdenite Re-Os dating. Also mentioned are magmatism, the mineralization pattern and deposits of granites, and high-sulfur magma.