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The production of synthetic iron castings in Russia comprises 50% of all alloys produced; therefore, increasing their smelting efficiency is an urgent task in the industry. This process depends primarily on the efficiency of industrial frequency induction crucible furnaces using acid lining. In the present study, the properties of quartzite, which forms the basis of such a lining, were investigated. An analysis of the proposed variants for changing the composition of the acid lining for use at temperatures of 1550–1600 °C was conducted. Following the preliminary temperature treatment of raw quartzite, which was then subjected to a sintering regime, we determined the conditions under which it was possible to obtain a phase state, allowing for the operation of the lining at temperatures above 1450 °C. We determined the use of an electrocorundum of two fractions as an additive to the traditional composition of the acid lining. The industrial testing of a new liner composition for the smelting of synthetic cast iron in an induction crucible melting furnace with a single steel scrap-metal filling was assessed, which required the use of an increased amount of carburizing agent. The positive results obtained can be explained by the study of the spent lining, which withstood 345 smelting methods of genophasic rent analysis. The results of the test are based on the results obtained in a study conducted on the finished coating of the product. [ABSTRACT FROM AUTHOR]

Secondary quartzites on Tyuters Island in the Gulf of Finland host long linear zones, up to 3 m thick, that are easily discernible in detailed satellite imagery. The zones consist of sillimanite–magnetite–kaolinite metasomatites, rocks that were first found in these zones. The metasomatites were produced at shattering of the quartzites and subsequent fluid introduction of material enriched in various components. The metasomatites are enriched in Al2O3 (16–23 wt %, as compared to 2–5 wt % in the quartzites). In contrast to the quartzites, iron in the metasomatic is contained mostly in the form of ferric oxide (whereas it occurs dominantly as ferrous oxide in the quartzites). The metasomatites contain practically no alkalis and alkali-earth elements and are enriched in Zn (146–199 ppm) and some other trace elements, including REE, first of all Ce (34 ppm) and La (17 ppm). Both the metasomatites and the quartzites show similar and insignificant REE fractionation: (La/Yb)n = 6.55 and 6.17. The metasomatites consist of the same minerals as the quartzites, but the proportions of these minerals and their composition in these rock types are different. It is worth mentioning magnetite of the metasomatites: it hosts abundant quartz inclusions with kaolinite rims. The quartz inclusions host, in turn, inclusions of magnetite crystallites. The metasomatites were produced in a number of stages of a metasomatic process, with changes in the fluid composition and its pH. The development of the metasomatites in the linear zones, the disintegration of their protolithic quartzites, and the high kaolinite contents in the rocks make these metasomatites similar, in a sense, to weathering crusts. However, the facts that the metasomatites and their protolithic quartzites consist of the same minerals, that the metasomatites contain absolutely no sulfides and sulfur but contain magnetite with complicated mineral inclusions make these rocks different from classic weathering crusts. [ABSTRACT FROM AUTHOR]

The petromagnetic properties of rocks from the Verkhnii Omolon, Magnetitovyi, Innyaga, and Alekseeskii areas of the Southern Omolon iron-ore district located in the southern part of the Omolon Massif (Northeast Russia) are investigated. The maximum values of natural remanent magnetization (NRM) and magnetic susceptibility ( k) of 22.8-1196 A/m and 1046 × 10 SI on average, respectively, are typical of ferruginous quartzite from the Innyaga site. The amphibolites exhibit high values of these magnetic parameters: J is approximately 28.6 A/m and k is 45 × 10 SI. The magnetic properties ( J and k) of the plagiogneisses and granite gneisses are highly heterogeneous and variable. The migmatites, rhyolites, and dacites are submagnetic. Magnetic minerals are largely represented by multidomain and pseudosingle-domain magnetites and their oxidation products such as maghemite, hematite, and iron hydroxides. It is revealed that the amphibolites are characterized by normal polarity of the remanent magnetization, while the ferruginous quartzites demonstrate normal and reverse polarities. These rocks may serve as sources of magnetic bipolar anomalies. [ABSTRACT FROM AUTHOR]

The article presents study on age and pressure-temperature (P-T) parameters of metamorphism of metaterrigenous-carbonate deposits of the Derba Block in East Sayan, Russia. It mentions the Derba Formation includes graphite bearing calcite marble and graphite-micaceous quartzite. It adds the representation of granitoids by quartz diorite, biotite plagiogranite and microcline granite.

The article explores the zirconology of iron quartzites (IQ) from the Taratash Complex (TC) of the Southern Urals in Russia which includes the nature of their substrates, age, and peculiarities of the evolution. It discusses the predominance of the metasomatic model among the hypotheses of the origin of IQ such as metasomatic, sedimentary, and sedimentary volcanogenic. It notes that pre-Riphean crystalline schists, graphite quartzites, and pyroxenites metamorphosed under the conditions of granulite facies were the substrate for the formation of TC. The general feature of zircon crystals from IQ of the TC is presented.

The article discusses a study on the sedimentation and metamorphism age of plagiogneisses rocks at Ganalskii Range (GR) in East Kamchatka, Russia. It states that plagiogneisses is viewed as one of the components at Ganalskii Range lower formation together with amphibolites, quartzites, and silicate marbles. It mentions that the rocks of granulite characteristics metamorphism serve an important role in the geological history of Ganalskii Range. It says that in evaluating the sedimentation age of plagiogneisses protolith, the study analyzed the rocks at upper areas of Vaktan Ganalskii Levy River and at the watershed between the rivers of Vaktan Ganalskii Sredny and Vaktan Ganalskii Pravy. It adds that the evolution of metamorphic rocks is presented by the sedimentation of volcanic strata.

Using local procedures, the new results on the isotope ages and composition of mineral inclusions were obtained for detrital zircons from Paleoproterozoic Jatulian terrigenous quartzites and polymictic conglomerates in Central and Western Karelia. For Eastern Laurasia, signs of the existence of Hadean and ancient Eoarchean matter were found for the first time (zircon grains of 3871 ± 38.6 and 3837 ± 42.1 Ma concordant ages). The multimodal distribution of ages within 3.45−2.61 Ga was revealed. The discovery of the oldest zircon grains provides the conditions for valid global correlations of geological events that determined the deposition and formation of the continental crust of the North Atlantic supercraton. [ABSTRACT FROM AUTHOR]

The article presents a study that seeks to determine the nature of zircon in quartzites existent since the Archean era which are found in mineral deposits of the Karelian craton, a region that separates Finland and Russia. It analyzes the mineral inclusions and alterations of zircon deposits with emphasis given on the average age of the mineral. It cites that studies on variations in the components of zircon minerals under hydrothermal alteration revealed that zircon grains do not contain mineral inclusions such as potassium feldspar, quartz and albite. Results also claim the presence of oldest zircons with age 3334±11 ―3296±29 Ma. Moreover, the study asserts that fluid nature noted in the zircon deposits are comparable with the ones found in Jack Hills, Australia.

Two epochs of the formation of ferruginous quartzites—Archean-Paleoproterozoic (3.2–1.8 Ga) and Neoproterozoic (0.85–0.7 Ga)—are distinguished in the Precambrian. They are incommensurable in scale: the Paleoproterozoic Kursk Group of the Kursk Magnetic Anomaly (KMA) extends over 1500 km, whereas the extension of Neoproterozoic banded iron formations (BIF) beds does not exceed a few tens of kilometers. Their thickness is up to 200 m and not more than 10 m, respectively. The oldest BIFs are located in old platforms, whereas Neoproterozoic BIFs are mainly confined to Phanerozoic orogenic (mobile) zones. Neoproterozoic BIFs universally associate with glacial deposits and their beds include glacial dropstones. In places, they underlie tillites of the Laplandian (Marinoan) glaciation (635 Ma), but they are more often sandwiched between glaciogenic sequences of the Laplandian and preceding Sturtian or Rapitan glaciation (730–750 Ma). Neoproterozoic BIFs are rather diverse in terms of lithology due to variation in the grade of metamorphism from place to place from low grades of the greenschist facies up to the granulite facies. Correspondingly, the ore component is mainly represented by hematite or magnetite. The REE distribution and (Co + Ni + Cu) index suggest an influence of hydrothermal sources of Fe, although it was subordinate to the continental washout. Iron was accumulated in seawater during glaciations, whereas iron mineralization took place at the earliest stages of postglacial transgressions. [ABSTRACT FROM AUTHOR]

Quartzites and paragneisses of the Archean granulite series of the Anabar Shield (Siberian Craton, Russia) are described geochemically. The Sm-Nd isotope systematics of the rocks and the U-Pb age (SHRIMP II) and geochemistry of zircons from quartzites and paragneisses are studied. Newly formed zircons from quartzites display geochemical characteristics of the magmatic type and were produced by rock anatexis upon granulite-facies metamorphism. The Paleoproterozoic age of the latest detrital zircons, 2250 ± 24 Ma, constrains the maximum age of sedimentary rock deposition. The anatectic rims around detrital zircons were formed ca. 2000 ± 9 Ma ago. The time of deposition of the sedimentary protolith of gneisses and quartzites falls within the age interval of the above-mentioned dates and is tentatively accepted as 2.1 Ga. The presence of Paleoproterozoic metasedimentary rocks in the Daldyn Group implies the tectonic heterogeneity of the series and the existence of Paleoproterozoic rock bodies among the predominant Archean rock sequences. [ABSTRACT FROM AUTHOR]