Hasil untuk "Mineralogy"

Peng Hu, Junjie Zeng, Yuxiao Xue et al.

High-Ti vanadium titanomagnetite (VTM) is much harder to be effectively utilized for sintering due to its higher TiO2 ratio. In this paper, the phase-transition mechanism of VTM sintering at different TiO2 ratios was systematically revealed by the analysis of theoretical thermodynamics, liquid phase formation characteristics and sinter compact mineralogy. Combined with mini-sintering tests, the effect of TiO2 ratio on the compressive strength and reducibility of VTM sinter compacts was verified and the appropriate TiO2 ratio was recommended. The results indicate that the gibbs free energy change of the reaction of TiO2 with CaO is much lower than that of Fe2O3 with CaO, which means perovskite (CaTiO3) is preferentially formed compared with silico-ferrite of calcium and aluminum (SFCA). Increasing TiO2 ratio improves liquid phase formation temperature and deteriorates liquid phase fluidity. Furthermore, SFCA amount is reduced and perovskite amount is increased, particularly at TiO2 ratio exceeding 4.00 wt%. Acicular and dendritic SFCA with higher strength and better reducibility is gradually transformed into tabular SFCA with relatively lower strength and poorer reducibility. The pore structure of sinter compacts is gradually developed. Thus, the compressive strength and reducibility index of sinter compacts are greatly reduced from 1734 N to 79.6 wt% to 1130 N and 67.9 wt% with TiO2 ratio increased from 2.00 wt% to 6.00 wt%. In addition, the compressive strength and reducibility index of sinter compacts are relatively better with TiO2 ratio no more than 4.00 wt%, which are consistently higher than 1400 N and 75 wt%.

I. Khan, X. Yang, X. Yang et al.

<p>This study examined the potential of quartz vein ore from the Peshawar Basin, Pakistan, as a raw material for producing high-grade, high-purity quartz sand. These samples were purified using a combination of methods including crushing, magnetic separation, ultrasonic cleaning, flotation, high-temperature calcination, water quenching, and acid leaching. Impurities in the quartz vein samples were analyzed through optical microscopy, SEM-CL, Raman spectroscopy, XRD, ICP-OES, and ICP-MS. Petrographic analysis revealed that the main impurities in quartz consisted of fluid inclusions, most of which were concentrated along the microfractures. After purification, the refined quartz sand exhibited a smooth surface with an extremely low concentration of gas–liquid inclusions. The ICP-OES bulk solution analysis of the raw quartz samples showed that the NB-1 SiO<span class="inline-formula">₂</span> content is 99.989 wt %, NB-2 99.989 wt %, and NB-3 99.990 wt %. The total impurity content in raw quartz ore was 104.73 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> for NB-1, 102.25 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> for NB-2, and 95.01 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> for NB-3. After purification, the ICP-MS analysis indicates the SiO<span class="inline-formula">₂</span> content in processed quartz was 99.999 wt % for NB-1, 99.997 wt % for NB-2, and 99.998 wt % for NB-3, and the total for the 13 impurity elements' content of refined quartz sand was 12.08 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> for NB-1, 34.57 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> for NB-2, and 16.79 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> for NB-3. The main impurity elements, Li and Al, were found in the following concentrations: NB-1 contained 2.06 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> of Li and 9.16 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> of Al, NB-2 had 3.23 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> of Li and 30.15 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> of Al, and NB-3 showed 2.09 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> of Li and 13.68 <span class="inline-formula">µ</span>g g<span class="inline-formula">⁻¹</span> of Al. These impurities can be further reduced using more advanced techniques. Based on these results, these purified quartz sands are suitable for producing high-purity quartz products (4N7 to 4N9) that meet the standard requirements for crucible preparation for industrial applications. Therefore, these quartz vein ores are considered potential resources for high-purity quartz (HPQ).</p>

Luis Alberto Pérez-García, Marianela Crespo-Lambert, Carlos Alberto Leyva- Rodríguez et al.

La agricultura urbana puede presentar riesgos para la salud humana y el medio ambiente cuando se desarrolla en suelos contaminados. Se llevó a cabo una revisión y análisis de la literatura publicada al respecto, buscando establecer analogías entre el desarrollo de la agricultura urbana y suburbana en el municipio de Moa y las potencialidades reales de bioacumulación de metales pesados. No obstante a la escasez de estudios específicos para Moa, la literatura disponible sugiere que existe una posibilidad real de contaminación de vegetales y hortalizas por metales pesados debido a la movilidad de estos elementos en el suelo, por lo que es un imperativo realizar estudios específicos y desarrollar estrategias adecuadas de mitigación para proteger la salud pública y el medio ambiente a partir de una estrategia de fito-remediación adaptada a las condiciones de Moa.

Jianhe Xie, Jianglin Li, Baifa Zhang et al.

Compared with traditional cement-based binders, alkali-activated binders can be improved upon combination with recycled aggregates to produce a promising and new green construction material. However, during this process, a pretreatment method is needed to alleviate the negative impact of recycled aggregates on the properties of alkali-activated materials. In this study, fly ash (FA), ground granulated blast furnace slag (GGBFS) and recycled powder (RP) were used as precursors, and recycled fine aggregates (RFAs) were used to replace natural fine aggregates (NFAs) to prepare recycled alkali-activated mortar (RAAM). Various RFA replacement ratios (0, 25%, 50% and 100%), pretreatment methods (calcination temperature and carbonation time) and alkaline moduli (0.8, 0.95, 1.1 and 1.25) were investigated. The effects of these parameters on the fresh and hardened properties, chemical composition and microstructure of RAAM were investigated. The results showed that the mechanical properties of RAAM gradually decreased with an increasing RFA replacement ratio due to the poor physical properties of RFA and its poor matrix binding. Two pretreatment methods (optimal calcination at 400 °C and carbonation at 6 h) were effective in improving the properties of RFA and thus the mechanical properties of RAAM. Calcination removed the adhered mortar from RFA and thus improved the mechanical properties of RAAM. Carbonation of RFA enhanced the quality of the attached mortar, which strengthened the RFA and provided better mechanical properties. In addition, microstructural analyses showed that RAAM prepared from pretreated RFA had a dense microstructure and a low critical pore size.

S. Raič, F. Molnár, F. Molnár et al.

<p>Discovering ore deposits is becoming increasingly difficult, and this is particularly true in areas of glaciated terrains. As a potential exploration tool for such terrains, we test the vectoring capacities of trace element and sulfur isotope characteristics of pyrite, combined with quantitative statistical methods of whole-rock geochemical datasets. Our target is the Rajapalot gold–cobalt project in northern Finland, where metamorphosed Paleoproterozoic volcanic and sedimentary rocks of the Peräpohja belt host recently discovered gold prospects, which also have significant cobalt enrichment. The focus is particularly put on a single gold–cobalt prospect, known as Raja, an excellent example of this unusual cobalt-enriched gold deposit, common in the metamorphosed terranes of northern Finland. The major lithologies at Rajapalot comprise amphibolite facies metamorphosed and polydeformed calcsilicate rocks that alternate with albitic units, mafic volcanic rocks, mica schist and quartzite. Mineralization at Rajapalot prospects is characterized by an older Co-mineralizing event and a younger high-grade Au mineralization with re-mobilization and re-deposition of Co. Detailed in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful technique that produces robust trace element and sulfur isotope databases from paragenetically and texturally well-characterized pyrite from the Raja prospect. The results are treated with appropriate log-ratio transformations and used for multivariate statistical data analysis, such as the computation of principal components. Application of these methods revealed that elements such as Co, Ni, Cu, Au, As, Ag, Mo, Bi, Te, Se, Sn, U, Tl and W have high vectoring capacities to discriminate between Co-only and Au–Co zones, as well as between mineralization stages. The systematic pyrite study suggests that homogenous sulfur isotopic characteristics (<span class="inline-formula">+</span>1.3 ‰ to <span class="inline-formula">+</span>5.9 ‰) and positive loadings of Co, Se, As, Te, Bi and Au onto PC1 are reflective of an early stage of Co mineralization, while the opposing negative loadings of Mo, Ni, W, Tl, Cu and Ag along PC1 are associated with pyrites from the Au-mineralizing event. The sulfur isotopic signature of the latter pyrite type is between <span class="inline-formula">−</span>1.2 ‰ and <span class="inline-formula">+</span>7.4 ‰. Subtle patterns recognized from the whole-rock geochemistry favor an As–Au–Se–Te–W–U signature along the positive axis of PC1 for the localization of high-grade Au–Co zones, whereas the element group Ni, Cu, Co, Te, Se and As, which has negative loadings onto PC2, will predict Co-only zones.</p> <p>This study shows the efficiency of trace element geochemistry in mineral exploration targeting, which has the capacity to define future targets by characterizing the metallogenic potential of a host rock, as well as distinguishing various stages of mineralization.</p>

Pedro Luis Dunán-Avila, Moraima Fernández-Rodríguez, Amalia Beatriz Riverón-Zaldívar et al.

The quality of water intended for irrigation is mainly determined by the content and type of salts present in it. The purpose of this research is to evaluate Yamanigüey River’s water quality for agricultural irrigation in 12 samples taken throughout the basin in preliminarily way. Performance of physicochemical parameters was evaluated and water quality was determined based on the values of sodium adsorption ratio, electrical conductivity, irrigation coefficient, potential salinity and effective salinity. It is concluded that waters on Yamanigüey River have a good to excellent quality and, according to Riverside standards, its water is suitable to use in agricultural irrigation, except in very low permeability soils for salinity and sodium sensitive crops.

Cole A. McCormick, Hilary Corlett, Jack Stacey et al.

Abstract Carbonate rocks undergo low-temperature, post-depositional changes, including mineral precipitation, dissolution, or recrystallisation (diagenesis). Unravelling the sequence of these events is time-consuming, expensive, and relies on destructive analytical techniques, yet such characterization is essential to understand their post-depositional history for mineral and energy exploitation and carbon storage. Conversely, hyperspectral imaging offers a rapid, non-destructive method to determine mineralogy, while also providing compositional and textural information. It is commonly employed to differentiate lithology, but it has never been used to discern complex diagenetic phases in a largely monomineralic succession. Using spatial-spectral endmember extraction, we explore the efficacy and limitations of hyperspectral imaging to elucidate multi-phase dolomitization and cementation in the Cathedral Formation (Western Canadian Sedimentary Basin). Spectral endmembers include limestone, two replacement dolomite phases, and three saddle dolomite phases. Endmember distributions were mapped using Spectral Angle Mapper, then sampled and analyzed to investigate the controls on their spectral signatures. The absorption-band position of each phase reveals changes in %Ca (molar Ca/(Ca + Mg)) and trace element substitution, whereas the spectral contrast correlates with texture. The ensuing mineral distribution maps provide meter-scale spatial information on the diagenetic history of the succession that can be used independently and to design a rigorous sampling protocol.

A.V. Kasatkin, S.Yu. Stepanov, M.V. Tsyganko et al.

The paper continues a series of publications devoted to the mineralogy of the Vorontsovskoe gold deposit in the Northern Urals (Kasatkin et al., 2020). The paper reports on native elements, sulfides, arsenides and tellurides discovered at the deposit, their chemical compositions, as well as unit-cell parameters and optical properties of some minerals. Getchellite, duranusite, pararealgar and picotpaulite are found for the first time in Russia.

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Ola Fredin, Giulio Viola, Horst Zwingmann et al.

A. V. Maslennikova, V. N. Udachin, D. V. Pirogov et al.

The paleolimnological study of the Lake Tavatui sedimentary record based on a multy-proxy approach provides reconstruction of the Late Glacial and Holocene environments of the Middle Urals. Spore-pollen spectra of the Late Glacial clay reflect several climate shifts between 13.25 and 11.7 ka cal BP. Lithology, mineralogy, geochemistry and spore-pollen spectra of the lake sediment core show follows Holocene environmental changes: ?11.2 ka cal BP, ? 10.6-10.4 ka cal BP, ?9.8 ka cal BP, ? 8.5-7.5 ka cal BP, ?5.8 ka cal BP, ?4.2 ka cal BP, ?3.5 ka cal BP and ? 2.3-2.2 ka cal BP. Lake sediments accumulated since the beginning of human-induced lake level increase (1914-1915 AD) characterized by an increase in Al, K, Rb, Zr, Cs, Be, Sc, V and Ga. These lithophil elements were used as the lake-level fluctuations indicators for the Holocene lake sediments.

Ramazan SARI, Ahmet TÜRKECAN, Mustafa DÖNMEZ et al.

Biga Yarımadası’nın 20 km batısında yer alan ve Türkiye’nin en büyük adası olan Gökçeada’ın jeolojisi, özellikle de magmatik kayaçları bu çalışmanın konusunu oluşturmaktadır. Gökçeada’nın kuzeybatısında tektonik yükselimle dar bir alanda yüzeyleyen Geç Ediakaran/Erken Paleozoyik yaşlı Çamlıca metamorfitleri adanın en yaşlı kayaçlarıdır. Çamlıca metamorfitleri üzerinde denizaltı yelpaze çökellerinden oluşan Erken Eosen yaşlı Karaağaç Formasyonu uyumsuz olarak yer alır. Çamlıca metamorfitlerini keserek Karaağaç Formasyonu içerisine yerleşen riyolitik lavlar ile tüf ve tüfitlerden oluşan Dağiçitepe volkanit üyesi ise çalışma sahasının en yaşlı volkanik birimidir. Karaağaç Formasyonu üzerinde uyumsuz olarak Orta Eosen yaşlı sığ denizel kumtaşlarından oluşan Koyunbaba Formasyonu çökelmiştir. Üzerinde ise uyumlu olarak GB-KD uzanımlı resifal kireçtaşından oluşan Soğucak Formasyonu bulunur. Soğucak Formasyonu üzerinde uyumlu olarak yer alan Orta-Üst Eosen yaşlı Ceylan Formasyonu ve Ceylan Formasyonu üzerinde de uyumlu olarak bulunan Erken Oligosen yaşlı Mezardere Formasyonu, derin denizel ortamda türbiditik akıntılara bağlı olarak çökelmişlerdir. Mesozoyik ve Eosen yaşlı birimleri keserek, Eosen yaşlı çökel birimler içerisine kriptodom ve dom şeklinde yerleşen ve çalışma sahasının bugünkü sert topoğrafyasını oluşturan Geç Eosen (?)- Oligosen yaşlı subvolkanitler, adadaki ikinci magmatik evre olup, Gökçeada Domları olarak isimlendirilmiştir. Subvolkanitlerin alt zonlarında kristalleşen diyorit-monzodiyorit porfirler ise Mutludere sokulumunu oluşturmaktadır. Gökçeada’nın doğusunda ve güneyinde Oligosen yaşlı Mezardere Formasyonu üzerinde pomza akmaları şeklinde izlenen Geç Oligosen yaşlı Gökçeada ignimbiriti yer alır. İgnimbiritin üzerine ise bloklu kül akmalarından oluşan Erken Miyosen yaşlı Kesmekaya volkanitleri gelir. Bazaltik andezit ile andezitik bileşimli lav ve piroklastitlerden oluşan Orta Miyosen yaşlı Eşelek volkanitleri Gökçeada’nın doğusunda genişçe bir alanda izlenir. Genellikle az pekişmiş konglomera, kumtaşı ve silttaşı ile marn ara katkılarından oluşan Üst Miyosen yaşlı Çanakkale Formasyonu Gökçeada’nın doğu, güneydoğu ve güneyinde dar alanlarda yüzeylemektedir. Gevşek, tutturulmamış, kum, silt, vb. çökellerden oluşan Kuvaterner yaşlı alüvyal çökeller ve yamaç molozları kendinden önce oluşmuş tüm birimleri uyumsuz olarak örterek istifi sonlandırırlar. Gökçeada’nın ana tektonik yapılarını Neo-tektonik dönemde gelişen sağ yanal atımlı oblik faylar oluşturmaktadır.

GAO Han, GUO Lei, GAO Jin-tao et al.

Based on in-situ observation,mineral evolution in high-phosphorous iron ore during the reduction process was investigated in the H2 atmosphere at different temperatures,and the influence of temperature on the morphology of iron was discussed. During the reduction process,ooliths in the iron ore remain. The mineral phases evolve faster with rising temperature,and so does the precipitation of iron from hematite phase. Significant segregation of iron happens at a higher temperature. Temperature has significant impact on the precipitation morphology of metallic iron. At 700℃,the precipitation of metallic iron forms a dense layer on the surface of particles. At 800℃,the precipitation morphology of metallic iron is complex,the density of the iron layer decreases,little holes appear while a small number of short iron whiskers are found. But at 900℃,the number of iron whiskers significantly increases with abundant porous sponge iron. Therefore,by adjusting the temperature and time,the sticking problem during the gas-based reduction process can be avoided,and meanwhile,efficient reduction of high phosphate iron ore is achieved.

F H Reza-e

The article studies the chemical deposits (mineralogy) and structure of the ores of Aynak ore deposits. This article have a results of macroscoping and microscoping reaserche after drilling of china company (MCC, 2010) and drilling of Russian geologist (1978).

HU Hai-xiang, FAN Zuo-peng, NIU Gui-qiang et al.

The capacity of ore treatment reached 12,000 t/d and gold recovery achieved 92% in the Jiaojia Gold Mine. Broken product has been washed with double spiral classifier, and the ore slime yield was 7%. The ore slime had also been flotation selected alone, which realized preliminary separation between slime and coarse sand. To further improve the gold recovery rate, the practice procedure was modified to subdivide the hydrocyclone in a grinding-flotation system, and the secondary and main slime was pumped into the current slime flotation system. In order to study the nature of overflow products, the experimental instruments were used in the test with Glance Polarizing Microscope, Stereoscopic Microscope, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Infrared Spectrum (IR) and Differential Thermal Analysis (DAT). Research results showed that the mineral species were composed of 4% metal sulfides and 96% gangue minerals. The metal sulfides consisted of about 70.17% pyrite and 16.27% chalcopyrite, whereas the gangue minerals were mainly quartz (about 47.12%) and feldspar (15.90%). The 65% gold was mainly hosted in pyrite and 20% in quartz. The particle size was finer, the content of single particles was higher and the conjuncture particles were less. The grain was finer, the pyrite content was higher and the distribution rate of Au and Ag was higher. The pyrite content reached 73.58% and Au & Ag accounted for 47.99% and 56.60% in -0.037 mm graded particles. The positive correlation was between gold allocation and pyrite content. Gold was not found in coarse grain, microscopic gold accounted for about 30% in medium grain and about 40% of gold in the fine fraction grain. Gold particle size was 2 to 10 microns in the range. Gold shapes were triangle, angular, small granular, irregular shape, etc. Based on infrared spectrum and differential thermal curve, it was found that the finer grain particle had a more complicated composition. Research conclusion provided the regulation for slime flotation from grinding-classification, which has an important practical significance for reagent regulation of slime flotation and determining flotation process.

Kimberly Casey, Andreas Kääb

We demonstrate spectral estimation of supraglacial dust, debris, ash and tephra geochemical composition from glaciers and ice fields in Iceland, Nepal, New Zealand and Switzerland. Surface glacier material was collected and analyzed via X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) for geochemical composition and mineralogy. In situ data was used as ground truth for comparison with satellite derived geochemical results. Supraglacial debris spectral response patterns and emissivity-derived silica weight percent are presented. Qualitative spectral response patterns agreed well with XRF elemental abundances. Quantitative emissivity estimates of supraglacial SiO2 in continental areas were 67% (Switzerland) and 68% (Nepal), while volcanic supraglacial SiO2 averages were 58% (Iceland) and 56% (New Zealand), yielding general agreement. Ablation season supraglacial temperature variation due to differing dust and debris type and coverage was also investigated, with surface debris temperatures ranging from 5.9 to 26.6 C in the study regions. Applications of the supraglacial geochemical reflective and emissive characterization methods include glacier areal extent mapping, debris source identification, glacier kinematics and glacier energy balance considerations.

Rimmelé G., Barlet-Gouédard V., Renard F.

Injection of carbon dioxide (CO2) underground, for long-term geological storage purposes, is considered as an economically viable option to reduce greenhouse gas emissions in the atmosphere. The chemical interactions between supercritical CO2 and the potential reservoir rock need to be thoroughly investigated under thermodynamic conditions relevant for geological storage. In the present study, 40 samples of Lavoux limestone and Adamswiller sandstone, both collected from reservoir rocks in the Paris basin, were experimentally exposed to CO2 in laboratory autoclaves specially built to simulate CO2-storage-reservoir conditions. The two types of rock were exposed to wet supercritical CO2 and CO2-saturated water for one month, at 28 MPa and 90°C, corresponding to conditions for a burial depth approximating 3 km. The changes in mineralogy and microtexture of the samples were measured using X-ray diffraction analyses, Raman spectroscopy, scanning-electron microscopy, and energy-dispersionspectroscopy microanalysis. The petrophysical properties were monitored by measuring the weight, density, mechanical properties, permeability, global porosity, and local porosity gradients through the samples. Both rocks maintained their mechanical and mineralogical properties after CO2 exposure despite an increase of porosity and permeability. Microscopic zones of calcite dissolution observed in the limestone are more likely to be responsible for such increase. In the sandstone, an alteration of the petrofabric is assumed to have occurred due to clay minerals reacting with CO2. All samples of Lavoux limestone and Adamswiller sandstone showed a measurable alteration when immersed either in wet supercritical CO2 or in CO2-saturated water. These batch experiments were performed using distilled water and thus simulate more severe conditions than using formation water (brine). <br> L’injection de dioxyde de carbone (CO2) en sous-sol pour un stockage géologique à long terme est considérée comme une solution pour contribuer à la réduction des émissions de gaz à effet de serre dans l’atmosphère. Les interactions entre le CO2 supercritique et la roche-réservoir potentielle doivent être étudiées en détail en conditions de stockage géologique. Quarante échantillons de calcaire de Lavoux et de grès d’Adamswiller, provenant de roches réservoirs du bassin parisien, ont été expérimentalement exposés au CO2 dans un autoclave spécialement construit pour reproduire les conditions thermodynamiques d’un réservoir de stockage de CO2. Les deux types de roches ont été exposés pendant un mois à du CO2 supercritique humide et à de l’eau saturée en CO2, à 28 MPa et 90 °C, ce qui correspond à des conditions d’enfouissement de 3 km de profondeur. L’évolution de leurs propriétés minéralogiques a été suivie par des analyses par diffraction des rayons X, par spectroscopie Raman et par microscopie électronique couplée à un système de microanalyses X. Leurs propriétés physiques et microtexturales ont été estimées en mesurant, avant et après les expériences, le poids, la densité, les propriétés mécaniques, la perméabilité, la porosité globale et la présence d’éventuels gradients de porosité de chaque échantillon. Les résultats montrent que les deux roches ont préservé leurs propriétés mécaniques et minéralogiques, malgré une augmentation de la porosité et de la perméabilité. Des zones microscopiques de dissolution de la calcite observées dans le calcaire sont vraisemblablement responsables de cette augmentation de la perméabilité et de la porosité. Dans le grès, une altération de la pétro-fabrique est supposée se produire due à la réaction des minéraux argileux avec le CO2. Tous les échantillons du calcaire de Lavoux et du grès d’Adamswiller ont montré une altération mesurable dans le CO2 humide et dans l’eau chargée en CO2. Ces expériences en autoclave sont effectuées en utilisant de l’eau distillée et donc simulent des conditions plus sévères que si elles étaient effectuées avec de l’eau de formation (saumure).

Holger Stünitz

J. Jedwab