Iron-containing Minerals Research Articles

Aerospace registration of hydrocarbon degassing

An active geological study of promising areas for oil and gas is being conducted in areas where geological signs of associated hydrocarbon manifestations are detected. The development of deposits contributes to a developed system of cracks in the surrounding rocks. Fluid supply to fractured reservoirs occurs through the channels of deep faults. Prolonged winter freezing of rocks inhibits the release of gases into the Earth’s atmosphere. The accumulation of hydrocarbon gases in the near-surface cavities creates risks of gas emissions, fires and explosions. Prediction and rapid diagnosis of gas emissions is based on planetary observations from satellites of ozone concentration in the atmosphere. V.L. Syvorotkin experimentally showed a causal relationship between hydrogen degassing and the formation of “Ozone Holes”. Satellite measurements of ozone concentrations in the atmosphere allow daily monitoring of hydrogen degassing sites from the Earth’s surface. The state of the soil surface in the areas of deep degassing is determined by secondary features. These are griffins, soil emissions, ring-shaped structures of gray soil (falling fertility), and hummocks of specific morphology. Such hummocks are formed as a result of the vital activity of “Hydrogen bacteria” and are markers of gas emission on the ground. In combination, methane with hydrogen is capable of detonation at concentrations ranging from 1%. The danger increases in the presence of iron-containing minerals that can catalyze the oxidation reaction. Preventive measures are proposed to prevent the sudden release of flammable gases: by drilling a network of control waste wells with a depth of 100 to 200 meters. Such wells are similar to ventilation wells in areas of coal mining.

Investigation of mineralogical and bacteria diversity in Nanxi River affected by acid mine drainage from the closed coal mine: Implications for characterizing natural attenuation process.

Due to the supply-side reform and environmental protection in China, many small coal mines have been closed since 2015. However, acid mine drainage from these coal mines are continuously discharging into many rural creeks, which requires the systematical investigation on the variations of geochemical and environmental biological aspects in these water systems. In this study, from a classic acid mine drainage (AMD) from a closed coal mine of Hunan, China, various sediments and water samples in different sections were collected and analyzed. According to the corresponding Mineralogical and simple bacterial characteristics analysis (16S rRNA gene sequencing), the main findings were: 1) Secondary iron-containing minerals gradually transited from Gr(CO32-) (green rust), Sh (schwertmannite) to Akg (Akaganeite) and more stable Gt (Goethite); 2) compared to the pristine sediment, these minerals decreased the acid-neutralizing capacity and cation exchange capacity (CEC) of sediments; 3) Proteobacteria and Firmicutes were the dominant phyla and the obvious variation of Firmicutes species was observed in the creek affected by AMD, which probably could been a biological index to diagnose the natural attenuation of AMD. These results could be greatly significant to understand typical variations of creek attenuation and bacterial community in the presence of high metal and sulfate concentration.

РОССЫПИ ЖЕЛЕЗОСОДЕРЖАЩИХ МИНЕРАЛОВ В САХАЛИНСКОЙ ОБЛАСТИ

Ю.А. Билибин неоднократно подчеркивал, что для того, чтобы понять картину образования россыпей, необходимо учитывать полный цикл их превращений. Много внимания было уделено в последнее время проблемам поиска древних погребенных россыпей и россыпей сложного строения. Богатые резервы полезных ископаемых в россыпях объясняются множественностью их генетических типов, позволяющих вовлекать в промышленную эксплуатацию новые месторождения. Актуальность работы обусловлена необходимостью выявления новых источников получения железа, титана и ванадия в условиях сокращения ресурсов минерально-сырьевой базы. Поисковые работы, выполняемые с целью выявления россыпей, наиболее перспективных для разработки, могут проводиться на основании понимания генезиса их формирования. Цель работы: исследование закономерностей распространения россыпей железистых минералов в пределах Сахалинской области, выявление петрогенетических особенностей преобладающих минералов, определение перспектив освоения месторождений железосодержащего сырья, оценка экономической целесообразности его добычи. Методы. Исследованы железо-титан-оксидные минералы из различных по кремнекислотности горных пород островодужных вулканогенных комплексов Большой Курильской гряды. Для исследований были подготовлены шлифы горных пород, отобрана магнитная фракция из протолочек. Шлифы пород изучались под поляризационным микроскопом. Порошок протолочек горных пород и мономинеральных фракций исследовался посредством химических аналитических методов (гравиметрического, титрометрического, спектрофотометрического, рентгенофлуоресцентного, масс-спектрометрического с индуктивно-связанной плазмой). Результаты. Исследованы закономерности формировании железистых россыпей и определены их основные типы. На побережьях Дальнего Востока России встречаются два типа россыпей с различными условиями питания. Одна из них – Курило-Камчатская провинция собственно титаномагнетитовых россыпей – расположена на территории Сахалинской области. На островах Курильской дуги преобладают современные пляжевые россыпи и дюнные отложения низкой террасы. Главная роль в обеспечении минералами россыпей этого типа принадлежит туфопесчаникам, пемзам и пемзово-шлаковым пирокластическим толщам. Кристаллы железосодержащих минералов в горных породах вулканогенных комплексов имеют довольно разнообразные размеры: от мелких, пылеватых до крупных хорошо выраженных кристаллов, размерами более 1–2 мм. Химический состав титаномагнетитов различных вулканических комплексов изменяется в зависимости от кремнекислотности пород. Продуктивные породы характеризуются повышенным содержанием железа, титана и ванадия. Прибрежно-морские, а также древние погребенные россыпи содержат значительные объемы железосодержащих минералов. Изучение технологических схем переработки железосодержащего минерального сырья показало, что некоторые из них позволят провести его переработку с получением востребованных конечных продуктов. При определенных экономических условиях разработка россыпей может быть целесообразной.

Global recycling experience of red mud - a review. Part i: pyrometallurgical methods

This review considers the papers aimed to find an effective solution to the red mud utilization problem. Red mud or bauxite residue is a hazardous materials that are generating during production of alumina by the Bayer process. Depending on the composition of bauxite and the technology, production of 1 ton alumina forms from 0.9 to 1.5 tons of this waste. The global inventory of red mud is estimated at about 4 billion ton in 2015. The main quantity of bauxite residue is not processed, but pumped into land-based ponds and it leads to environmental pollution. In 2010 in Hungary a pond containing red mud were collapsed, freeing about 700 thousand m3 of liquid waste, as a result 10 people were died, about 350 houses were destroyed and significant regions were polluted. Red mud obtained by different plants has various chemical and phase compositions. Despite this fact the main components of red mud is iron-containing minerals, so bauxite residue can be considered primarily as a raw material for the metallurgical industry. This part of the review considers pyrometallurgical methods for of red mud treatment, including both methods of low-temperature reduction at temperatures of 1050 - 1200 °C and high-temperature reduction melting, as well as utilization methods of the resulting slags. These slag utilization methods can be used for extraction of alumina, titanium and rare-earth metals, obtaining building materials such as various cements, mineral wool and flux materials for metallurgy. Methods of alkali removing, drying and agglomeration of red mud also considered. It has been shown that the best ways of bauxite residue recycling are the pyrometallurgical methods with obtaining of iron-containing product and slag for the production of building materials or metallurgical fluxes. These techniques make possible to utilize a large amount of red mud with exception of additional waste formation. This is the first part in a series of three related reviews examining the world experience of red mud recycling by various ways.

Visible Light Driven Organic Pollutants Degradation with Hydrothermally Carbonized Sewage Sludge and Oxalate Via Molecular Oxygen Activation.

Converting sewage sludge into functional environmental materials has become an attractive sewage sludge disposal route. In this study, we synthesize a sewage sludge-based material via a facile one-pot hydrothermal carbonization method and construct a visible light molecular oxygen activation system with hydrothermally carbonized sewage sludge (HTC-S) and oxalate to degrade various organic pollutants. It was found that iron species of HTC-S could chelate with oxalate to generate H2O2 via molecular oxygen activation under visible light, and also promote the H2O2 decomposition to produce •OH for the fast organic pollutants degradation. Taking sulfadimidine as the example, the apparent degradation rate of HTC-S/oxalate system was almost 5-20 times that of iron oxides/oxalate system. This outstanding degradation performance was attributed to the presence of iron-containing clay minerals in HTC-S, as confirmed by X-ray diffraction measurements and Mössbauer spectrometry. In the oxalate solution, these iron-containing clay minerals could be excited more easily than common iron oxides under visible light, because the silicon species strongly interacted with iron species in HTC-S to form Fe-O-Si bond, which lowered the excitation energy of Fe-oxalate complex. This work provides an alternative sewage sludge conversion pathway and also sheds light on the environmental remediation applications of sewage sludge-based materials.

An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations.

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the deep ocean. Roles of minerals are critical in many hydrothermal organic geochemical processes. Traditional hydrothermal methodology, which includes using reactors made of gold, titanium, platinum, or stainless-steel, is usually associated with the high cost or undesired metal catalytic effects. Recently, there is a growing tendency for using the cost-effective and inert quartz or fused silica glass tubes in hydrothermal experiments. Here, we provide a protocol for carrying out organic-mineral hydrothermal experiments in silica tubes, and we describe the essential steps in the sample preparation, experimental setup, products separation, and quantitative analysis. We also demonstrate an experiment using a model organic compound, nitrobenzene, to show the effect of an iron-containing mineral, magnetite, on its degradation under a specific hydrothermal condition. This technique can be applied to study complex organic-mineral hydrothermal interactions in a relatively simple laboratory system.

Beneficiation of Low-Grade Laterite Nickel by Calcination-Magnetic Separation Method

In this research, Effect of thermal treatment on beneficiation of low-grade laterite nickel by calcination-magnetic separation method was studied. In order to determine the components and elements of the sample, to recognize the main and minor minerals and their bond, and phase transformation caused by thermal treatment, Chemical analysis (XRF and ICP), microscopic studies and XRD analysis were done, respectively. SEM analysis was done to study the content of nickel and other minerals. In order to determine the phase transformation of the sample because of calcination treatment, thermal analysis of DTA/TG and XRD analysis, before and after of calcination were done. Wet magnetic separation tests with two methods of calcination-magnetic separation and only magnetic separation were done on the sample and the results in grade and recovery of nickel concentrate were compared. According to results, nickel content in the sample was0.94%. Main minerals of laterite sample were Hematite, Goethite, Quartz, and dolomite and minor minerals were Magnetite and minerals of serpentine group. Furthermore, there is no independent nickel mineral in the sample. SEM studies declared that nickel was substituted in iron-containing minerals (Hematite and Goethite). XRD and thermal analysis (DTA/TG) showed that at 350 °C, Goethite transformed to Hematite and at 750 °C, Hematite transformed widely to Magnetite. Calcination of feed at 750°C followed by wet magnetic separation with the magnetic field of 6000 Gauss in comparison with alone magnetic separation caused an increase in recovery and grade of magnetic concentrate to 12.7% and 0.41%, respectively. Results showed that an increase in temperature of more than 750 °C, caused a decrease in recovery and grade of nickel in magnetic concentrate.

Degradation of ethylthionocarbamate by pyrite-activated persulfate

Ethylthionocarbamate (ETC) is the most widely used collector in the flotation of sulfide minerals. However, it is known to cause serious pollution to soil and groundwater systems. Pyrite is the most abundant iron sulfide mineral in the Earth's crust, and can effectively activate persulfate (PS) to produce SO4−. Compared with heavy metals, natural iron-containing minerals are relatively non-toxic, inexpensive, and environment-friendly PS activators that can be used for removing refractory organic pollutants. In this study, batch experiments were conducted to investigate ETC degradation by pyrite-activated PS. The activation mechanism, and the effect of various factors, namely, initial pH, pyrite dosage, PS concentration, and coexisting ions, were examined. ETC was efficiently degraded by pyrite-activated PS, and its degradation increased with increasing pyrite dosage and PS concentration, and decreasing pH. Moreover, the presence of Mn2+, Cu2+, CO32−, PO43−, and HCO3− had a significant inhibitory effect on ETC degradation, in the following order: PO43− > HCO3− > CO32− > Mn2+ > Cu2+. These findings indicate that the PS-pyrite system provides a new method for ETC removal from flotation wastewater.

Atmospheric Processing and Iron Mobilization of Ilmenite: Iron-Containing Ternary Oxide in Mineral Dust Aerosol.

Over the last several decades, iron has been identified as a limiting nutrient in about half of the world's oceans. Its most significant source is identified as deposited iron-containing mineral dust that has been processed during atmospheric transportation. The current work focuses on chemical and photochemical processing of iron-containing mineral dust particles in the presence of nitric acid, and an organic pollutant dimethyl sulfide under atmospherically relevant conditions. More importantly, ilmenite (FeTiO3) is evaluated as a proxy for the iron-containing mineral dust. The presence of titanium in its lattice structure provides higher complexity to mimic mineral dust, yet it is simple enough to study reaction pathways and mechanisms. Here, spectroscopic methods are combined with dissolution measurements to investigate atmospheric processing of iron in mineral dust, with specific focus on particle mineralogy, particle size, and their environmental conditions (i.e., pH and solar flux). Our results indicate that the presence of titanium elemental composition enhances iron dissolution from mineral dust, at least by 2-fold comparison with its nontitanium-containing counterparts. The extent of iron dissolution and speciation is further influenced by the above factors. Thus, our work highlights these important, yet unconsidered, factors in the atmospheric processing of iron-containing mineral dust aerosol.

Hydrogeochemical and biomedical insights into germanium potential of curative waters: a case study of health resorts in the Sudetes Mountains (Poland)

Germanium is considered to be a non-essential element; however, little is still known about its significance for living organisms. It exerts prophylactic and therapeutic effects in the treatment of serious diseases such as cancer, HIV infection, and others. Germanium does not exhibit acute toxicity, but, as it tends to accumulate in various organs and tissues, undesirable and even dangerous side effects have been reported after prolonged and/or high dosage application. In general, inorganic compounds of germanium are more toxic than its organic compounds. Further studies should be performed to elucidate the exact molecular mechanism of germanium action, to determine the safe and effective dose of germanium via curative/mineral waters, and to understand the applications and benefits of using germanium-enriched waters in balneotherapy. The geochemistry of curative (cold CO2-rich, thermal) waters from spas in the Sudetes (Poland) was clarified in terms of components and mineral phases which might govern germanium. Germanium and silicon in thermal (above 20 °C) waters presumably result from the solubility of silicates in crystalline (granites, gneisses) aquifer rocks and might be controlled by neo-formed quartz. The cold CO2-rich waters revealed a significant diversity of aqueous chemistry and relationships of germanium with iron, silicon, or arsenic. Locally, both in sedimentary (sandstones) and metamorphic (gneisses) aquifer rocks, primary (silicates) and/or secondary (oxides) iron-containing minerals likely release germanium into solution. In the CO2-rich waters of the western part of the Kłodzko Region, germanium distinctly correlates with arsenic. It is hypothesized that both elements are co-sourced from crystalline basement and/or migration of substances of post-magmatic origin along deep-seated dislocations related to the seismically active Poříčí-Hronov fault zone. This area was proposed as the most prospective one for finding waters rich in germanium in the Sudetes.

Effect of the Intensification of Mechanical Processing on the Conversion of the Mineral Matter of Coal Fuel

The influence of intense preliminary mechanical processing in a disintegrator on the conversion of the mineral matter of Kuznetsk black coal was determined. With the use of X-ray spectral fluorescence analysis and a method of coal sample separation based on density, a significant redistribution of the mineral components with the use of an energy-intensive mill (disintegrator) was found in comparison with standard mills utilized in heat-power engineering in terms of both particle-size fractions and density. Crushing in the disintegrator leads to a more uniform distribution of mineral substances over the fractions. A small fraction becomes enriched in mineral elements such as calcium- and iron-containing minerals bound to the organic matter. The separation based on density showed that crushing in the disintegrator leads to a significant decrease in the concentration of iron-containing minerals and a decrease in the portion of organic components in the heavy fraction, as compared with crushing in a ball–tube mill.

Effects of iron-containing minerals on hydrothermal reactions of ketones

Hydrothermal organic transformations occurring in geochemical processes are influenced by the surrounding environments including rocks and minerals. This work is focused on the effects of five common minerals on reactions of a model ketone substrate, dibenzylketone (DBK), in an experimental hydrothermal system. Ketones play a central role in many hydrothermal organic functional group transformations, such as those converting hydrocarbons to oxygenated compounds; however, how these minerals control the hydrothermal chemistry of ketones is poorly understood. Under the hydrothermal conditions of 300 °C and 70 MPa for up to 168 h, we observed that, while quartz (SiO2) and corundum (Al2O3) had no detectable effect on the hydrothermal reactions of DBK, iron-containing minerals, such as hematite (Fe2O3), magnetite (Fe3O4), and troilite (synthetic FeS), accelerated the reaction of DBK by up to an order of magnitude. We observed that fragmentation products, such as toluene and bibenzyl, dominated in the presence of hematite or magnetite, while use of troilite gave primarily the reduction products, e.g., 1, 3-diphenyl-propane and 1, 3-diphenyl-2-propanol. The roles of the three iron minerals in these transformations were further explored by (1) control experiments with various mineral surface areas, (2) measuring H2 in hydrothermal solutions, and (3) determining hydrogen balance among the organic products. These results suggest the reactions catalyzed by iron oxides (hematite and magnetite) are promoted mainly by the mineral surfaces, whereas the sulfide mineral (troilite) facilitated the reduction of ketone in the reaction solution. Therefore, this work not only provides a useful chemical approach to study and uncover complicated hydrothermal organic-mineral interactions, but also fosters a mechanistic understanding of ketone reactions in the deep carbon cycle.

Mössbauer study of iron minerals transformations by Fuchsiella ferrireducens

Biogenic transformations of iron-containing minerals synthesized ferrihydrite, magnetite and hydrothermal siderite by anaerobic alkaliphilic bacterium Fuchsiella ferrireducens (strain Z-7101T) were studied by 57Fe Mossbauer spectroscopy. Mossbauer investigations of solid phase samples obtained after microbial transformation were carried out at room temperature and at 82 K. It was found that all tested minerals transformed during bacterial growth. In the presence of synthesized ferrihydrite, added as an electron acceptor, a mixture of large (more than 100 nm) and small (∼5 nm) particles of magnetically ordered phase and siderite was formed. Synthesized magnetite that contains both Fe3+ and Fe2+ forms could serve as electron acceptor as well as an electron donor for F.ferrireducens growth. As a result of its biotransformation, no siderite formation was observed while small particles of magnetite were formed. In the case of the addition of siderite as an electron donor formation of a small amount of a new phase containing Fe2+ caused by recrystallization of siderite during bacterial growth was detected.

Effect of Chemical Compositions on Ash Fusibility Characterization of a Jincheng Anthracite during Combustion and Gasification

The ash melting temperature of coal ash has an important effect during the fluidized bed combustion and gasification process, which affects the slagging and deposition characteristics of the boiler. Experiments on the effects of chemical components on the ash fusion behaviors have been completed on the ash fusion temperatures (AFTs) analyzer under typical gasification and combustion atmospheres. Meanwhile, calculations on the variation of minerals in ash with ash composition were conducted using the FactSage software. The results indicated that the AFTs under gasification were a little higher than those under the combustion atmosphere. On increasing the Fe2O3, CaO, and Na2O contents under the combustion and gasification atmospheres, the four temperatures deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT) decreased dramatically and the generation and transformation of minerals occurred. The iron-containing minerals, such as hercynite and fayalite, formed with increase in the content of Fe2O3; the Ca-bearing feldspar minerals, like gehlenite and anorthite, started appearing on increasing the CaO content, and the Na-containing feldspar minerals, like carnegieite, were detected as the Na2O was increased. These three minerals can form low-temperature eutectics, decreasing the fusion temperature.

Reduced Iron-Containing Clay Minerals as Antibacterial Agents.

Previous work documented the general antibacterial mechanism of iron containing clays that involved hydroxyl radical (•OH) production from soluble Fe2+, and attack of cell membrane and intracellular proteins. Here we explore the role of clay structural Fe(II) in •OH production at near neutral pH and identify a lipid involved in the antibacterial process. Structural Fe(III) in nontronite NAu-2 was reduced (rNAu-2) and E. coli, a model bacterium, was exposed to rNAu-2 in oxic suspension. The antibacterial activity of rNAu-2 was dependent on pH and Fe(II) concentration, where E. coli were completely killed at pH 6, but survived at pH 7 and 8. In the presence of a •OH scavenger or in anaerobic atmosphere, E. coli survived better, suggesting that cell death may be caused by •OH generated from oxidation of structural Fe(II) in rNAu-2. In-situ imaging revealed damage of a membrane lipid, cardiolipin, in the polar region of E. coli cells, where reactive oxygen species and redox-active labile Fe were enriched. Our results advance the previous antibacterial model by demonstrating that the structural Fe(II) is the primary source of •OH, which damages cardiolipin, triggers the influx of soluble Fe2+ into the cell, and ultimately leads to cell death.

Fe(II)–Fe(III) Electron Transfer in a Clay Mineral with Low Fe Content

Iron-containing clay minerals are ubiquitous in soils, sediments, and water and provide a significant source of redox-active Fe that is known to influence metal sorption, contaminant fate, and nutrient cycling. While biological reduction of clay minerals has been known for some time, it has only recently been shown that Fe(II) can abiotically reduce Fe(III) in clay minerals. Here, we used Mossbauer spectroscopy to show that Fe(II) reduces an extensive amount of Fe(III) in a low-Fe clay mineral (Wyoming montmorillonite, SWy-2, 2.3 wt % Fe). The extent of reduction ranges from 12 to 78% over a pH range of 4.0–7.5 and Fe(II) concentration from 0.4 to 2.2 mM and increases as the amount of sorbed Fe(II) increases until about half of the mineral is reduced. It is unclear how such extensive reduction occurs in an Fe-bearing clay mineral with such a low Fe concentration. With only 2.3 wt % Fe in SWy-2, Fe atoms in the clay mineral are spatially isolated and electron conduction or hopping between neighboring Fe at...

Reductive dechlorination of carbon tetrachloride by bioreduction of nontronite

Reductive dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (FeII3(PO4)2·8H2O)). In the presence of CT, an acceleration of CT dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1.8 times higher than that by CN32 alone (37%). Significant amounts of formate (30.1%) and CO (2.4%) were measured during the CT dechlorination in the nontronite suspension with CN32. Results obtained from Fe(II) measurement and X-ray diffraction (XRD) showed the acceleration of Fe(II) production after 13 d and the formation of vivianite in the range of 13–25 d, suggesting that the biogenic vivianite enhanced the CT dechlorination in this study. Experimental results from batch kinetic tests, Fe(II) measurements, XRD analysis, and by-product study suggested that the formation of vivianite can play a crucial role for the enhanced reductive dechlorination of CT in phosphorous enriched subsurface environments with iron-containing clay minerals.

Mineralogical and physical beneficiation studies for iron extraction from Bardaskan titanomagnetite placer deposit

In this work, a bench-scale process was developed using mineral-processing methods to recover iron from a placer deposit located in Bardaskan, Khorasan-e-Razavi, Iran. The mineralogical studies were performed by X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Electron Probe Micro-Analyzer (EPMA), and an optical microscope. These studies indicated that titanomagnetite, magnetite, and hematite were presented in the sample as valuable minerals. In contrast, the gangue minerals were silicates such as pyroxene, plagioclase, quartz, feldspar, calcite, and some secondary minerals. The optimum liberation degree of the iron-containing minerals was obtained to be 75 µm with average Fe and TiO2 contents of 5% and 1%, respectively. The analysis showed that magnetite was the main iron mineral, and most of the hematite was formed due to martitization. Also minor ilmenite contents were found in hematite and magnetite in a blade form. The maximum TiO2 content in the magnetite lattice was 19%, only 8% of which was recovered to the magnetic product. Eventually, an iron concentration flow sheet was developed, which included the removal of a major part of silicates and then iron minerals by a low intensity wet magnetic separator. The final product contained 55, 7.8, and 0.77% of Fe, TiO2, and V2O5, respectively, which can be used for iron production, and V2O5 extraction (as the by-product).

Simulation of CO2 injection in a small-scale pilot site in the Pohang Basin, Korea: Effect of dissolution rate of chlorite on mineral trapping

In Korea, a small-scale pilot project for CO2 injection was launched to target an offshore reservoir within the Pohang Basin. The objectives of this study are to present the effects of CO2 injection in a sloping aquifer on the evolution of the CO2 plume and its impact on mineral trapping using TOUGHREACT. The results show that the CO2 plume is asymmetrical and rapidly migrates along the slope in the up-dip direction from the injection well. With the migration of the CO2 plume, the increased acidity accelerates the water-rock interactions. As the CO2-water-rock interactions start quickly due to the rapid spreading of the CO2 plume, the amount of mineral trapping slightly increases due to the precipitation of siderite by chlorite dissolution. However, the stability of siderite is sensitive to the dissolution rate of chlorite. At low chlorite dissolution rates, siderite is more stable than ankerite in an undersaturated state. At high chlorite dissolution rates, ankerite is more stable because of the higher pH. In addition, the amount of mineral trapping increases considerably up to 3.7kg/m3, which is about 90 times that at the initial rate (0.04kg/m3). This simulation indicates that the uncertainty in the dissolution rate of chlorite must be considered when estimating the capacity of mineral trapping in situations in which iron-containing carbonate minerals significantly influence the mineral trapping.

Prospects of radiation-thermal treatment of wastes of Novosibirsk Tin Works

The experimental test data on magnetic properties of the waste iron-containing mineral materials under radiation-thermal treatment are presented. It is found that the volume magnetic susceptibility of pyrite- and arsenopyrite-containing wastes has increased 5 times on the average. The authors demonstrate that radiation-thermal magnetization and magnetic separation allows production of KOS-3 grade tin concentrate meeting fuming process requirements from wastes of Novosibirsk Tin Works.