scholarly journals MINERAL COMPOSITION OF HIGH-GRADE IRON ORES THAT ARE ONE OF THE COMPONENTSOF COARSE GRAINED SCREENINGS FROM CRUSHING AND SCREENING PLANTS IN THE KRYVYI RIH BASIN

2017 ◽  
Vol 2 (77) ◽  
pp. 77-81 ◽  
Author(s):  
O. Demchenko ◽  
◽  
V. Evtekhov ◽  
H. Georgiieva ◽  
◽  
...  
Keyword(s):  
Mineral Composition ◽  
Coarse Grained ◽  
High Grade ◽  
Iron Ores

The Gongchangling BIFs from the Anshan–Benxi area, NE China: Petrological–geochemical characteristics and genesis of high-grade iron ores

2014 ◽  
Vol 60 ◽  
pp. 112-125 ◽  
Author(s):  
Xiao-Hui Sun ◽  
Xiao-Qing Zhu ◽  
Hao-Shu Tang ◽  
Qian Zhang ◽  
Tai-Yi Luo
Keyword(s):  
Geochemical Characteristics ◽  
High Grade ◽  
Iron Ores ◽  
Ne China

scholarly journals Mineralogy of Zirconium in Iron-Oxides: A Micron- to Nanoscale Study of Hematite Ore from Peculiar Knob, South Australia

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 244 ◽  
Author(s):  
Keyser ◽  
Ciobanu ◽  
Cook ◽  
Feltus ◽  
Johnson ◽  
...  
Keyword(s):  
South Australia ◽  
Coarse Grained ◽  
Iron Deposit ◽  
High Grade ◽  
Microscopy Imaging ◽  
Grade Metamorphism ◽  
Icp Ms ◽  
High Grade Metamorphism ◽  
Hematite Ore

Zirconium is an element of considerable petrogenetic significance but is rarely found in hematite at concentrations higher than a few parts-per-million (ppm). Coarse-grained hematite ore from the metamorphosed Peculiar Knob iron deposit, South Australia, contains anomalous concentrations of Zr and has been investigated using microanalytical techniques that can bridge the micron- to nanoscales to understand the distribution of Zr in the ore. Hematite displays textures attributable to annealing under conditions of high-grade metamorphism, deformation twins (r~85˚ to hematite elongation), relict magnetite and fields of sub-micron-wide inclusions of baddeleyite as conjugate needles with orientation at ~110˚/70˚. Skeletal and granoblastic zircon, containing only a few ppm U, are both present interstitial to hematite. Using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analysis and mapping, the concentration of Zr in hematite is determined to be ~260 ppm on average (up to 680 ppm). The Zr content is, however, directly attributable to nm-scale inclusions of baddeleyite pervasively distributed throughout the hematite rather than Zr in solid solution. Distinction between nm-scale inclusions and lattice-bound trace element substitutions cannot be made from LA-ICP-MS data alone and requires nanoscale characterization. Scandium-rich (up to 0.18 wt. % Sc2O3) cores in zircon are documented by microprobe analysis and mapping. Using high-angle annular dark field scanning transmission electron microscopy imaging (HAADF-STEM) and energy-dispersive spectrometry STEM mapping of foils prepared in-situ by focused ion beam methods, we identify [011]baddeleyite epitaxially intergrown with [22.1]hematite. Lattice vectors at 84–86˚ underpinning the epitaxial intergrowth orientation correspond to directions of r-twins but not to the orientation of the needles, which display a ~15˚ misfit. This is attributable to directions of trellis exsolutions in a precursor titanomagnetite. U–Pb dating of zircon gives a 206Pb/238U weighted mean age of 1741 ± 49 Ma (sensitive high-resolution ion microprobe U–Pb method). Based on the findings presented here, detrital titanomagnetite from erosion of mafic rocks is considered the most likely source for Zr, Ti, Cr and Sc. Whether such detrital horizons accumulated in a basin with chemical precipitation of Fe-minerals (banded iron formation) is debatable, but such Fe-rich sediments clearly included detrital horizons. Martitization during the diagenesis-supergene enrichment cycle was followed by high-grade metamorphism during the ~1.73–1.69 Ga Kimban Orogeny during which martite recrystallized as granoblastic hematite. Later interaction with hydrothermal fluids associated with ~1.6 Ga Hiltaba-granitoids led to W, Sn and Sb enrichment in the hematite. By reconstructing the evolution of the massive orebody at Peculiar Knob, we show how application of complimentary advanced microanalytical techniques, in-situ and on the same material but at different scales, provides critical constraints on ore-forming processes.

scholarly journals Högbomite from the Aldan Shield, Eastern Siberia, USSR

1989 ◽  
Vol 53 (371) ◽  
pp. 376-379 ◽  
Author(s):  
Edward S. Grew ◽  
Galina M. Drugova ◽  
N.V. Leskova
Keyword(s):  
Thin Section ◽  
Aldan Shield ◽  
Complex Oxide ◽  
Chemical Data ◽  
High Grade ◽  
Iron Ores ◽  
Eastern Siberia ◽  
Recent Increase ◽  
New Localities

Högbomite, a complex oxide of A1, Fe, Mg, and Ti, is an important constitutent of some iron ores and emery deposits as well as an infrequent accessory in aluminous high-grade rocks (e.g. Grew et al., 1987). The recent increase in reports of new localities (e.g. Rammlmair et al., 1988) suggests that högbomite may be more widespread than is generally perceived. We report here högbomite from the Aldan Shield, Eastern Siberia. This högbomite is remarkable for the wide variation in composition measured in a single thin section. Our report is only the second from the USSR of högbomite for which chemical data are given.

Gold Remobilization: Insights from Gold Deposits in the Archean Swayze Greenstone Belt, Abitibi Subprovince, Canada

2020 ◽  
Vol 115 (2) ◽  
pp. 241-277 ◽  
Author(s):  
Evan C.G. Hastie ◽  
Daniel J. Kontak ◽  
Bruno Lafrance
Keyword(s):  
Greenstone Belt ◽  
Inductively Coupled Plasma ◽  
Native Gold ◽  
Gold Deposits ◽  
Coarse Grained ◽  
High Grade ◽  
Northern Ontario ◽  
Inductively Coupled ◽  
Abitibi Subprovince ◽  
Plasma Mass Spectrometry

Abstract Recognizing if and how Au is remobilized, in solid, melt, or fluid state, is critical for understanding the origin of high-grade ore zones in Au deposits. When evidence for Au remobilization can be demonstrated, then primary versus secondary processes can be distinguished, resulting in a more complete understanding of Au deposit formation. To address this, samples from two Au deposits, Jerome and Kenty, in the Archean Swayze greenstone belt of northern Ontario, Canada, together with archived samples from 39 high-grade Au deposits from the Abitibi greenstone belt across Ontario and Quebec, were geochemically characterized using integrated scanning electron microscopy-energy dispersive spectroscopy and electron microprobe imaging and analyses in addition to laser ablation-inductively coupled plasma-mass spectrometry elemental mapping. These data provided the basis to develop a model for Au remobilization and upgrading of Au that is widely applicable to orogenic gold settings. Data for the Jerome deposit indicate that Au uptake into early pyrite was not due to pulsing of different fluids, but instead was predominantly controlled by S availability, whereby the oscillatory/sector zoning in pyrite resulted from the substitution of As into S sites during rapid growth due to local chemical disequilibrium. In addition, Au-bearing pyrite from both the Jerome and Kenty deposits records textures, such as porosity development coincident with the presence of native gold and accessory sulfide phases, that are strongly suggestive of coupled dissolution-reprecipitation (CDR) reactions that liberated Au and associated elements from earlier auriferous (100–5,000 ppm Au) pyrite. During the remobilization process, Au and Ag were decoupled, which resulted in (1) a change in Au/Ag ratios of 0.5 to 5 in early pyrite to ≈9 in the new native gold (900 Au fineness) and (2) incorporation of Ag into cogenetic secondary mineral phases (e.g., chalcopyrite, tetrahedrite, and galena). Evidence for an association of low-melting point chalcophile elements (LMCE; Hg, Te, Sb, and Bi) with Au at the Jerome, Kenty, and many (>50%) of the 39 historic deposits sampled, along with native gold filling structurally favorable sites in vein quartz in all samples, indicates a fluid might not have been the only factor contributing to remobilization. This systematic Au-LMCE association strongly supports a model whereby Au is released by CDR reactions and is then remobilized by fluid-mediated, LMCE-rich melts that began to form at 335°C and/or by local, nanoparticle (nanomelt?) transport during deformation and metamorphism. Conclusions drawn from this study have implications for Au deposits globally and can account for the common presence of coarse-grained, commonly crystalline, native gold filling fractures in quartz and the paragenetically late-stage origin of gold in veins. They can also better explain the inability of Au in solution remobilization models to account for locally high gold grades, given the relatively low solubility of Au in hydrothermal fluids.

How High Grade Iron Ores And Agglomerates Will Affect Coke Rates

JOM ◽  
1956 ◽  
Vol 8 (4) ◽  
pp. 439-442
Author(s):  
John Griffen
Keyword(s):  
High Grade ◽  
Iron Ores

Research on Coarse-Grained Soil Collapsibility in Gobi Region

2012 ◽  
Vol 446-449 ◽  
pp. 1450-1453 ◽  
Author(s):  
Zhi Hong Nie ◽  
Kun Li ◽  
Jian Xia
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mineral Composition ◽  
Load Test ◽  
Coarse Grained ◽  
Soil Test ◽  
Internal Reasons ◽  
High Degree ◽  
Scanning Electron ◽  
Coarse Grained Soil

This paper has carried out soaking load test, routine soil test, X diffraction, scanning electron microscopy on coarse-grained soil in Gobi region, analyzed the coarse-grained soil collapsibility and explored the mechanism of collapsibility generation. The results showed that: the coarse-grained soil in Gobi region had a high degree of collapsibility; mineral composition, microstructure and salinity constituted the main internal reasons resulting in such phenomenon. In soaking conditions, the cementation strengthen between grains reduces, the structure is damaged under external force and the grain movement leads to greater settlement.

scholarly journals Application of Nano High-Entropy Alloys to Reduce Energy Consumption and Wear of Copper Oxide and High-Grade Iron Ores in Heavy Mining Industries—A Case Study

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 16
Author(s):  
Mohammadreza Heydartaemeh ◽  
Mohammad Karamoozian ◽  
Herman Potgieter
Keyword(s):  
Copper Oxide ◽  
Alloy Steel ◽  
Base Alloy ◽  
International Markets ◽  
Work Piece ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
High Grade ◽  
Iron Ores ◽  
High Entropy

Problems relating to the abrasion of equipment is one of the most important issues in mining and associated industries. Hardening is a method of protecting metal equipment, metal tools, or important components against erosion, corrosion, and abrasion. This can be achieved by welding a thin layer of abrasion-resistant metal onto the surface of the work piece. The useful life of a piece of equipment or parts can be significantly increased by applying abrasion-resistant coatings, thereby reducing repair or replacement costs associated with damaged parts. This process is inexpensive in the production of parts and is often economically justifiable. This study focuses on measuring the abrasion resistance of a nano high-entropy alloy against copper oxide and high-grade iron ores. When a base alloy was coated with the nano high-entropy alloy, the abrasion indexes of iron and copper ores decreased from 0.0001647 kg to 0.0000908 kg and from 0.0001472 kg to 0.0000803 kg, respectively. The standard deviation, repeatability, and reproducibility were calculated for the alloy steel blade covered with nano high entropy alloy (N-HEA), producing values of 0.00016, 0.00047, and 0.00040, respectively, while a standard alloy steel blade exhibited values of 0.0003, 0.00047, and 0.00042, respectively. High-entropy alloys and high-entropy nano-alloys have not been used as practical coatings in the mineral industry in any form to date. Utilizing high-entropy nano-alloys in this industry would introduce innovative alternatives for customers, thereby increasing competitive advantages and providing international markets and customers = with the most efficient choices of operational materials.

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