Ore Resources Research Articles

Simultaneous Recovery of Niobium and Sulfur from Carbonate Niobite Ore with Flotation

Exploring new ways to acquire niobium resources is essential to resolve niobium supply risks, due to the fact that, at present, 99% of niobium is controlled by only two countries. In the present work, a flotation technique was applied to separate niobium from low-grade niobite ore. To maximize the utilization of the original ore resources, pre-flotation was conducted to recover sulfur and eliminate the adverse effects of sulfide on niobite flotation. The obtained sulfur grade and recovery were 33.74% and 92.04%, respectively, and its concentration ratio was 40x. As for the niobite flotation, a closed-circuit experiment with one rougher flotation, three cleaner flotations, and two scavenger flotations was carried out to achieve the maximum niobite recovery. To further improve the niobite recovery, a leaching process with diluted HCl was employed; the final obtained Nb2O5 grade and recovery were 30.19% and 65.04%, respectively, and the concentration ratio reached 242x. Moreover, the economic evaluation implies that the flotation process can attract great positive interest.

120\xa0years of georesources research in Switzerland: the Swiss Geotechnical Commission (1899\u20132018)

Geological surveys have a wide range of tasks for their countries: to map the geology and to assess the georesources potential for metallic ores, industrial minerals, geothermal energy, fossil fuels, aggregates and groundwater. In Europe, most countries founded geological surveys around the mid-nineteenth century in order to create an overview of the geological resources they wanted to exploit. In Switzerland, at that time, the industrial revolution triggered a tremendous demand for infrastructure and energy raw materials. However, no national georesources institution was established when the nation-forming process among the 25 cantons culminated in the foundation of the Swiss Federal State in 1848. The Swiss Geological Survey was founded 138 years later in 1986. How did Switzerland map the country, assess the resource potential and provide fundamental data for land use planning without such an organisation? This paper elaborates on the evolution of Swiss institutions mandated to study the geological resources, with a focus on the Swiss Geotechnical Commission (SGTK, 1899–2018). Given the low financial resources, no long-term nation-wide investigation programs could be implemented. The commission's study program was mainly driven by external societal and political factors. World War I for example reactivated the search for coal which was intensively exploited during those years. Before and during World War II, the focus temporarily shifted to oil and gas exploration. From 1970 onwards, SGTK was involved in several applied research projects and collaborations with various industry partners. In this paper, we revisit the key turning points in the evolution of the commission's investigation program, including related financial and organisational aspects, and discuss how Switzerland’s federalistic structure influenced the geological survey activities. The history of the SGTK represents an exemplification of how a nation managed its geological survey activities, until 1986 in the absence of a geological survey and without large hydrocarbon and metallic ore resources and a corresponding, significant mining industry. The SGTK case also shows that flexible, project-based investigations can be advantageous as they respond to current challenges at short notice. This could to some degree substitute the initial absence of a geological survey, as shown by the numerous SGTK monographs that are key references also 100 years after their publication.

Comparison of various forces acting on magnetic particles in a low-intensity magnetic field: A 3D FEA

Magnetic agglomeration plays a vital role in enhancing the separation of fine magnetic mineral particles. However, the forces causing magnetic agglomeration in wet low-intensity magnetic separators (LIMS) are poorly understood; this calls for improved understanding of various forces (including magnetic force (Fm), magnetic agglomeration force (Fmm), gravity (G)) acting on magnetic particles in the LIMS. In this study, a 3D low-intensity magnetic field (LIMF) with uniform gradient was simulated, and the different forces acting on magnetic particles were calculated in the form of Fmm/Fm and Fmm/G by finite element analysis (FEA). Results show that magnetic agglomeration force has a significant competitive effect on magnetic separation. However, there are still some methods to weaken the effect of magnetic agglomeration force. This study not only provides theoretical guidance for the innovative development of LIMS, but also opens a new perspective for the recovery of strong magnetic minerals from ore resources.

Physicochemical Aspects of Oxidative Consolidation Behavior of Manganese Ore Powders with Various Mn/Fe Mass Ratios for Pellet Preparation.

With the depletion of rich manganese ore resources, plentiful manganese ore powders with various Mn/Fe mass ratios are produced. The physicochemical aspects of oxidative consolidation behavior of manganese ores with various Mn/Fe mass ratios were investigated in this work to determine whether manganese ore powders with high iron content (Fe-Mn ore) can be prepared as high-quality pellets. Physicochemical properties of the pellets were investigated, including cold compression strength (CCS), phase transformation, microstructural evolution, Vickers hardness (HV), porosity, and lattice parameter. CCS testing indicated that the strength of roasted Fe-Mn ore pellets was observably lower than that of pure hematite or manganese ore pellets. Phase and morphology results showed that in Fe-Mn ore pellets, an Mn ferrite phase was generated between hematite and pyrolusite particles. However, newborn Mn ferrites and hematite had an obvious crystal boundary in the crystallographic particles. Moreover, poorly crystallized Mn ferrite particles were evident, along with Mn and Fe element concentration gradients, due to the inadequate diffusion of metal ions. This resulted in poor mechanical properties of the Fe-Mn ore pellets. A temperature over 1275 °C and a roasting time of 15 min is required for the oxidative consolidation of Fe-Mn ores. In such optimized cases, Mn, Fe, O, and Al elements were uniformly distributed in the well-crystallized Mn ferrite grains, which provided favorable mineralogy for the consolidation of Fe-Mn ore powders.

Thermal Decomposition of Siderite Ore in Different Flowing Atmospheres: Phase Transformation and Magnetism

ABSTRACT Siderite ore (FeCO3) is an important iron ore resource that is widely distributed around the world. However, it is difficult to process using conventional methods owing to the low iron grade, easy sliming, and high impurity content. Based on the mechanism of thermal decomposition, the combination of metallurgy and processing is a promising method to process siderite ore. In this study, experiments on thermal decomposition were performed using a fluidization reactor in flowing atmospheres of N2, CO, and CO2. The phase transformation and magnetism were characterized via X-ray diffraction, Mössbauer spectroscopy, and vibrating sample magnetometry. The results indicated that the thermal decomposition of siderite ore exhibited significant differences in various atmospheres, particularly for the phase transformation and magnetism, which primarily depended on a two-step function: FeCO3 → FeO + CO2 → Fe3O4 + CO. It has implications for the utilization of siderite ore resources.

High-Performance Fe-Based Prussian Blue Cathode Material for Enhancing the Activity of Low-Spin Fe by Cu Doping.

Iron-based Prussian blue (FeHCF) has great application potential in the large-scale production of sodium-ion (Na+) batteries because of its high theoretical capacity and abundant Fe ore resources. However, the Fe(CN)6 vacancies and crystal water seriously affect the electrochemical performance. Herein, a Cu-doped FeHCF (Cu-FeHCF) cathode material is successfully prepared directly by a coprecipitation method. After Cu doping, the monoclinic structure and the quasi-cubic morphology are retained, but the electrochemical performance is significantly improved. In addition to few Fe(CN)6 vacancies and low crystal water, the improved performance is also related to the enhanced electrochemical activity of low-spin Fe and the stabilizing effect of Cu on the crystal structure. Moreover, Cu doping also controls the side reaction to a certain extent. As a result, after Cu doping, the initial discharge capacity is enhanced from 107.9 to 127.4 mA h g-1 at 100 mA g-1, especially the capacities contributed by low-spin Fe increase from 30.0, 21.7, and 16.7 mA h g-1 to 48.8, 45.4, and 43.7 mA h g-1 for the first three cycles, respectively. Even at 2 A g-1, Cu-FeHCF still has a promising initial capacity of 82.3 mA h g-1 and only a 0.047% capacity decay rate for each cycle over 500 cycles. Therefore, Cu-FeHCF shows excellent application potential in the field of Na+ energy storage batteries.

Identification of Iron Ore Deposit in Sub-Surface Using Electrical Resistivity and Induced Polarization Methods in Nangabulik, Central Kalimantan

Nangabulik, Lamandau Regency was one of the territories in Central Borneo that has potential for iron ore resources. A lot of geophysics methods can be used for exploration, among electrical resistivity and induced polarization methods. Then research is conducted to analyze the distribution model of resistivity and chargeability values in the subsurface, interpreting the location of iron ore based on resistivity and chargeability parameters, investigating alignment zone of iron ore deposit, and analyze the estimated total of iron ore resource. The configuration used is Wenner Alpha with 4 passes, each of which length is 235 m. Based on the 2D inversion result, resistivity and chargeability values were 21,15 – 96.153,51 Ωm and chargeability 23,6 – 542,58 ms. The iron ore deposit is to be found at GL-01, GL-02, and GL-04 tracks marked by resistivity value 614,22 – 5.803,90 Ωm and contrast in chargeability value around 212,32 – 542,58 ms. Large resistivity value due to porous between pebble–boulder iron ore fragments shape with pyroclastic rock grains filled the air. Based on the 3D model there was not found alignment zone of iron ore deposit at the research region. The total estimated deposit iron ore resource in the research region, at area ± 6 hectares is 41.036 tons.

Batch scale study on magnetizing roasting of low-grade iron ore tailings using fluidized bed roaster

The present steel production of India is 111.24 MTPA in January 2019 as per the Ministry of Steel, Govt. of India. The demand for steel production is increasing day by day. Depleting the high-grade iron ore resources compels steel industries to utilize the low/lean grade iron ore to meet future demand. However, there is no technology available that can directly use these low-grade iron ore. Further, these iron ores are dumped in different mine heads and slime ponds as waste creating environmental and societal problems. Therefore, it is need of the hour to develop suitable scientific methods where these low and lean grade iron ore can be effectively utilized. Magnetizing roasting of this low and lean-grade iron-ore followed by low-intensity magnetic separation can produce high-grade magnetite. The present study focused on the reduction roasting of a tailing iron ore sample having 47.47 %Fe in a batch-type fluidized bed roaster. The roasting of the sample was conducted at a temperature of 1000 °C and varying residence time from 2 to 10 min. Non-coking coal was employed as a reductant for the reduction reaction. The fluidization velocity was maintained at 1.5–1.7 times the minimum fluidization velocity. Then, the roasted sample was subjected to LIMS to obtain a high-grade magnetite concentrate. The study reveals that 61.1-grade iron ore can be obtained at 2 min residence time with 48.4% and 62.5% yield and recovery.

ОЦЕНКА ПЕРСПЕКТИВ РАЗВИТИЯ ЧЕРНОЙ МЕТАЛЛУРГИИ ИРКУТСКОЙ ОБЛАСТИ НА ОСНОВЕ РЕСУРСОВ ВОСТОЧНЫХ САЯН И ИННОВАЦИОННЫХ ТЕХНОЛОГИЙ

The creation of the East Siberian metallurgical base is an indispensable condition for the implementation of reindustrialization processes, including industrial and civil construction, engineering for the mining industry, the chemical industry, etc. The existing opportunities are the formation of a promising heavy-duty iron ore base for the Urals and Western Siberia based on the Bakcharskoye deposit causes the creation in Eastern Siberia of mining and metallurgical enterprises, mainly of local importance. Perspective restrictions on the use of natural gas in iron production, environmental and investment restrictions for blast-furnace production determine the use of liquid-phase iron reduction technologies using thermal coals. The concentration of groups of iron ore deposits in the Irkutsk region makes it possible to create mining and metallurgical plants near the cities of Ust-Ilimsk, Taishet, Tulun. The involvement of significant resources of titanomagnetites is possible when solving the problem of developing more efficient technologies for producing metallic titanium. The object of the research is resources of iron-ore and coal deposits in the Irkutsk region in the process of assessing the possibility and efficiency of their use in the prospective mining and metallurgical industries. The subject of the research is technological and resource prerequisites for location of large objects of mining-metallurgical complexes for direct production of iron in Irkutsk region. The aim of the research is to identify promising deposits and occurrences of iron ore and coal raw materials, taking into account the possibilities of application of existing technical and technological solutions for transportation, enrichment and metallurgical processing for complex processing. The objectives of the research are: to assess the potential of large iron ore deposits of Western Siberia using new technologies to meet the needs of metallurgical enterprises in the Urals and Kemerovo region; to determine a new concept of promising metallurgical base of Eastern Siberia; to determine a promising base for the placement of mining and metallurgical plants in the Irkutsk region. Methodology and research methods. The research methodology is based on a systematic representation of the mining-metallurgical complex created on the territorial combination of raw materials and fuel in accordance with the theory of energy-production cycles, in which promising (innovative) technologies are implemented. When determining the degree of priority development of titanium-magnetite deposits, the possibility of using the resulting titanium-containing products is taken into account. It is also shown that the main metallurgical base of the Irkutsk region can be created in the area of the city of Tulun on the basis of the use of iron ore resources of the Eastern Sayan. The fuel base is provided by the resources of the Irkutsk coal basin. To reduce investment and current costs associated with the transportation of coal and ore or concentrates, it is proposed to use slurry pipelines

Nanostructured SiO2 material: synthesis advances and applications in rubber reinforcement.

Silica is a commercially significant material due to its extensive use in widespread applications and products. Synthetic amorphous silica (SAS) is a form of SiO2 that is intentionally manufactured and has been produced and marketed for decades without significant changes in its physico-chemical properties. The industrial production of nanostructured SiO2 is nowadays challenged by the expensive raw material use and high energy consumption. The search for non-petroleum-based fillers such as nanostructured SiO2, which are environmentally friendly, cheap, abundant, renewable, and efficient, has been initiated nowadays. Therefore, a large number of research activities have been carried out so far for the preparation of SAS from potential alternate precursors, i.e., synthetic chemicals, biogenic, and mineral ore resources. Reinforcement of rubbers with nanostructured SiO2 fillers is a process of great practical and technological importance for improving their mechanical, dynamic, and thermal properties. The efficiencies of SiO2 reinforcement correlate with different factors such as filler structure, surface area, rubber–filler interactions, and filler–filler interactions with their effects. This review paper discusses the recent synthesis advances of nanostructured SiO2 from synthetic chemicals, biogenic and mineral ore resources, their physical characteristics, and applications in rubber reinforcement, overcoming challenges. Finally, summary and future work recommendations have been mentioned well for future researchers.

РЕСУРСНО-СЫРЬЕВАЯ БАЗА ИТКУЛЬСКОЙ МЕТАЛЛУРГИИ РАННЕГО ЖЕЛЕЗНОГО ВЕКА СРЕДНЕГО ЗАУРАЛЬЯ

The paper addresses the question of ore resources (occurrences and deposits) exploited by the Early Iron Age metallurgists of the Itkul culture in the middle Urals. The main method of the study was the analysis of geological maps and reports, and the analysis of the correlation between the identified ore occurrences and the Itkul culture metal production centers. The results of the study reveal a relationship between the location of the Itkul culture settlement clusters and various types of copper ore (VMS, skarn and stratiform) and iron ore (infiltration and sedimentary ironstone) deposits, which could have been exploited for copper, and iron metallurgy in antiquity. We suggest that the primary smelting of copper ore was performed only in clusters: Polevskoy, Itkulsky, Isetsky and Irtyashsky. The use of ironstone ores is attested in copper metallurgy, where they were added into the charge as fluxes to reduce the viscosity of the slag melt and more efficiently extract copper from the ore. The Itkul metallurgical settlements seem also to have direct evidence of iron smelting. The ironstone deposits of infiltration-sedimentary type, common in the middle Trans-Urals, were apparently one of the main ore sources used. The provided geological maps showing the location of the possible iron and copper metallic resources make it possible to localize areas having the potential for finding new archaeological evidence of ancient mining and primary metallurgical operations. Based on these data, the first early Iron Age iron ore mine was discovered in the Urals.

International trade network resilience for products in the whole industrial chain of iron ore resources

International trade network resilience for products in the whole industrial chain of iron ore resources

Uplift-exhumation and preservation of the Yumugou Mo-W deposit, East Qinling, China: Insights from multiple apatite low-temperature thermochronology

As a result of the continued depletion of shallow ore resources, there has been renewed focus on the tectonic preservation of mineralized systems. Specifically, it is vital to constrain the post-mineralization exhumation and preservation history of existing economic deposits, in order to identify new regions suitable for mineral exploration. In this study, we present results from apatite U-Pb, fission-track and (U-Th-Sm)/He thermochronological and associated thermal history modeling studies on the Yumugou Mo-W deposit within the world-class East Qinling Mo polymetallic metallogenic belt, central China. Our major aim is to constrain the exhumation history and to evaluate preservation potential of the Yumugou Mo-W deposit, and provide related guidance for mineral exploration in the East Qinling Orogen. Apatite U-Pb dating yield Early Cretaceous lower intercept Terra-Wasserburg ages in the range of 153–141 Ma, interpreted as crystallization age of apatite, coeval with the formation of Yumugou deposit (ca. 145 Ma). Integrated apatite fission-track and apatite (U-Th-Sm)/He dating give ages varying from Late Cretaceous to Early Paleogene, representing the post-mineralization cooling ages. We also integrate these age data with confined fission-track length measurements and geological constraints from previous studies into the thermal history models, the resulting models suggest three cooling pulses: 1) a phase of Early Cretaceous (125–100 Ma) rapid cooling, followed by 2) a phase of Late Cretaceous (100–73 Ma) slow cooling, before finally, 3) a phase of Late Cretaceous to Paleogene (73–50 Ma) rapid cooling. The Early Cretaceous rapid cooling pulse correlates temporally with extension tectonic setting in the East Qinling Orogen, the magma emplacement and post-magmatic rapid cooling at ca. 160–130 Ma in the Luanchuan region might cause related exhumation at ca. 125–100 Ma to upper crustal temperatures. The Late Cretaceous slow cooling possibly corresponds to regionally slow extensive erosion in response to crustal shortening triggered by the westward subduction of the Paleo-Pacific Plate at this time. The Late Cretaceous-Paleogene rapid cooling likely result from the major far-field effects of the Pacific Plate subduction and the sinistral strike-slip motion of the Tan-Lu Fault Zone, as well as possible minor expansion effects derived by the Paleogene India-Eurasia collision. Moreover, we adopt thermal history modeling method to determine cooling rate, exhumation rate and depth of different cooling stages. In comparison with the calculated exhumation depth (∼5.6 km) and previously reported metallogenic depth (3–7 km) in the Luanchuan ore cluster, we infer that more than one kilometer metallogenic depth is theoretically preserved in the Yumugou Mo-W deposit. Combined the similar metallogenic setting and features with other giant Mo deposits in the East Qinling Orogen, we further suggest that the Mo deposits in this orogen possibly have underwent a similar degree of exhumation and show good prospecting potential.

Study on the high-efficiency separation of Fe and Mn from low-grade pyrolusite and the preparation of LiMn2O4 materials for lithium-ion batteries

• No any reducing agent is used in whole recovery process. • The separation effect of pyrolusite by sulfidation roasting is satisfactory. • The conversion process of manganese oxide is studied in detail. There is a serious shortage of high-grade manganese ore resources, so the development and utilization of low-grade manganese ore are of great significance. In this paper, the mixed roasting/water leaching method of sulfuric acid and pyrolusite is used to efficiently recover Mn and Fe elements. Under the optimal process conditions, acid/ore ratio of 2:1, water/acid ratio of 1:5, the roasting temperature of 650 °C, and holding time of 4 h, the leaching rates of Mn and Fe are 99.10% and 0.67%, respectively. Additionally, the conversion process between manganese-containing precipitate and manganese oxide is studied, and high-purity Mn 3 O 4 is obtained. LiMn 2 O 4 , an electrode material for lithium-ion batteries, is successfully prepared by solid-phase synthesis with Mn 3 O 4 as a manganese source. The initial charge specific capacity of the LiMn 2 O 4 is 115.7 mAh·g −1 at 0.1C. Additionally, the charge specific capacity of the LiMn 2 O 4 is still 78.64 mAh·g −1 after 100 cycles at 1C. The process does not use any reducing agents, surfactants, etc., and has the characteristics of short, simple, easy-to-operate, economical, and reasonable process, which is helpful to realize the efficient recovery and reuse of manganese and iron resources in the pyrolusite.

Hydrothermal and Metasomatic Kaolin Resource Estimation in the Quang Ninh area, Northeastern Vietnam

In northeastern Vietnam, hydrothermal‐metasomatic kaolinite-pyrophyllite from the secondary quartzite origin has been found in many places, including Pin Ho, Ban Ngai, Khe Khoai, Pec Sec Leng, Tan Mai ore occurrences, etc. They are exploited together with pyrophyllite, alunite, and high‐alumina quartzite as a byproduct. There were 810 chemical and mineral samples in the Quang Ninh area collected to investigate hydrothermal‐metasomatic kaolin resources. The ore minerals consist of kaolin-group minerals (kaolinite, dickite), pyrophyllite, quartz with minor sericite, alunite, diaspora, etc. They were identified by X-ray diffraction, and microscope and scanning electron microscope coupled with energy-dispersive X-ray spectroscopy analyses. Chemical analyses of major oxides were carried out on clays and parent rock samples by X-ray fluorescence spectrometry. The similarity-analogy in ore geology and mineral resource estimation based on statistical methods are employed to estimate hydrothermal‐metasomatic kaolin resources from the Quang Ninh area in northeastern Vietnam. The mineral resource estimation based on statistical methods shows 2.21 million tons of kaolin obtained by the content of aluminum oxide over 28% of the Pec Sec Leng mine, accounting for 14.3% in total. The similarity-analogy in ore geology indicates 158.16 million tons of kaolinite-pyrophyllite ores, of which, 22.0 million tons are kaolin. These methods display that the Quang Ninh area contains mainly pyrophyllite rather than kaolin resources. Our study suggests that the Quang Ninh area can be considered as a potential pyrophyllite resource in northeastern Vietnam for future exploration. Furthermore, the one resource estimation based on similarity-analogy in ore geology method shows an overview of the prospect on kaolinite-pyrophyllite resources in the Quang Ninh area, northeastern Vietnam.

Prospects of green extraction of iron from waste dumped flotation tailings by H2: A pilot case study

Flotation tailings are a secondary iron ore resource with abundant reserves and recycling value. In this study, low-grade flotation tailings (TFe = 21.86%) with silica of 57.85% has been studied by the hydrogen-based suspension magnetization roasting (HSMR) and magnetic separation varying the roasting temperature, reductant concentrate, total gas flow, and feeding rate to evaluate their effect on iron grade and iron recovery in magnetic concentrate. According to the pilot case study, the best iron concentrate (Fe grade of 66.65% and recovery of 80.11%) was obtained at a temperature of 500 °C, H2 concentration of 14.4%, the total gas flow of 18.0 m3/h, and feeding rate of 100 kg/h. After HSMR, the phase transformation results indicated that the weakly magnetic of hematite in flotation tailings were transform to the stronger magnetic magnetite, and the iron in magnetite increased from 17.57% in flotation tailings to 97.73% in magnetic concentrate. Microstructure analysis is presented which shows that the HSMR process destroys the structure of the iron minerals particles, making them form more pores and microcracks, which greatly reduces the structural strength of the particles and helps to reduce the energy consumption of the grinding operation. This study provides a pilot case of HSMR for the green and low-carbon development of the iron and steel industry.

The 2018–2019 excavation of the Xiwubi site in Jiangxian County, Shanxi

Abstract A series of excavations were conducted at the Xiwubi site during 2018–2019, yielding abundant copper metallurgy remains dating to the Erlitou and Erligang cultural periods. Archaeological features include remains of smelting furnaces, charcoal kilns, houses, and refuse pits. A variety of artifacts were retrieved, ranging from copper ores, fragments of smelting furnaces, crucibles, and slag to objects made of pottery, stone, and bone. It is the first copper metallurgy site found in the Zhongtiao Mountains in the vicinity of the heartland of the Xia and Shang dynasties. Characterized by early dates, large scale, and advanced specialization in copper metallurgy, the excavation of the Xiwubi site provides substantial materials for the study of mining and use of copper ore resources by the Xia and Shang dynasties, as well as interactions between copper metallurgy and the destiny of the royal courts.

Mineralogical Characterization of Manganese Oxide Minerals of the Devonian Xialei Manganese Deposit

The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined.

Geochronology and geochemistry of mineralized and barren intrusive rocks in the Yemaquan polymetallic skarn deposit, northern Qinghai-Tibet Plateau: A zircon perspective

The Yemaquan polymetallic skarn deposit is located in the Qimantagh metallogenic belt (QMB), northern Qinghai-Tibet Plateau, China, with total ore resources of 82.7 million metric tons at 29.46 percent Fe, 0.40% Cu, 2.08% Pb and 1.77% Zn. In this study, new trace element composition of zircon in tandem with LA-ICP-MS U-Pb geochronology are provided for mineralized and barren intrusive rocks occurring within two magnetic anomaly areas (M1 and M13) at the Yemaquan deposit. These data, combined with whole rock major and trace element compositions, allow to constrain the geochronological framework and magmatic processes for different types of intrusive rocks within the district.The zircon U-Pb ages reveal that the polymetallic mineralization in the M1 and M13 anomaly areas results from two temporally distinct intrusive centers. Different to the M13 area where only the mineralized Devonian intrusions are recorded, both mineralized and barren intrusive rocks in the M1 area were emplaced in the Late Triassic. Whole rock major and trace elements indicate that both Triassic mineralized and barren rocks underwent significant fractional crystallization, with the Triassic barren rocks displaying much stronger plagioclase fractionation. In contrast, the limited whole rock silica range and high Eu/Eu* of Devonian mineralized intrusions indicate that they did not experience evident fractionation. Zircon trace elements show that the two mineralized groups at Yemaquan display similar, high zircon Ce/Ce* but distinguishable Eu/Eu* ratios, which suggest a consistent, high magmatic oxidation state but different water content. The magmatic water content of Devonian mineralized rocks higher than that of their Triassic counterparts probably suggests that the former are more Cu-fertile. This study confirms that both Devonian and Triassic intrusive activities are responsible for skarn Fe-Cu-Pb-Zn mineralization at the Yemaquan deposit. Meanwhile, in view of the general feature of Yemaquan in the context of skarn deposits from the QMB, we thus suggest that in future mineral exploration great attention should be paid to both the Triassic and Devonian intrusive rocks.

Decomposition test study on short-process mechanical strengthening equipment of alkali decomposition of tungsten ore

The traditional alkali decomposition process and equipment of tungsten ore are limited by the situation that the grade of tungsten ore resources is decreasingy and the impurity content is getting higher and higher. A set of high-efficiency alkali decomposition process equipment of tungsten ore based on mechanical strengthening is researched and developed in this paper. Fourteen groups of mechanical strengthening decomposition tests were carried out on three particle sizes of ore samples. which verifies the feasibility and reliability of strengthening the alkali decomposition of tungsten ore by the test prototype.