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Date submitted2024-05-06
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Date accepted2024-06-14
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Date published2024-07-04
Natural carbon matrices based on brown coal, humic acids and humine extracted from it for purification of aqueous solutions from low molecular weight organic impurities
Heterogeneous systems including natural carbon matrices in the solid phase and aqueous solutions of low molecular weight organic compounds with positive and negative variations from ideality in the liquid phase are considered. The technical characterization of the considered supramolecular ensembles on the basis of brown coal of the Kara-Keche deposit (Kyrgyzstan), humic acids and humine extracted from it is given. Functional analysis of the samples was carried out using FTIR spectroscopy. The morphology of the surface of the considered carbon matrices has been investigated, in different points of which the local microelement composition has been established. An X-ray phase analysis of Kara-Keche brown coal and humic acids and humine extracted from it was carried out. The isothermal adsorption of bipolar molecules of glycine and urea, neutral D-glucose from aqueous solutions on solid carbon sorbents has been studied. An assumption has been made about the adsorption of low molecular weight organic compounds from aqueous solutions on humine and Kara-Keche coal in irregularities and pores of the carbon matrix of sorbents, for humic acids – on surface reaction centers. Due to its developed pore structure and resistance to acids and alkalis, humine from Kara-Keche coal is recommended for the purification of industrial wastewater from low molecular weight organic ecotoxicants.
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Date submitted2022-04-14
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Date accepted2022-07-21
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Date published2022-11-03
In-situ leaching of molybdenum and uranium by percarbonate and chloride-hypochlorite solutions
In-situ leaching of molybdenum and uranium is becoming an increasingly common process. The features of the material composition of ores, leading to a decrease in their filtration properties, were considered. Activation leaching with leaching solutions that have undergone electrophotochemical activation before contact with the ore mass were studied. Activation preparation of leaching solutions promotes the synthesis of clustered water molecules with collectivized protons and hydroxyl ions, as well as active forms of oxygen and hydrogen. Cell leaching of molybdenum from mature tailings of the Shakhtaminsk deposit was studied experimentally. After pre-oxidation with an active carbonate solution, a model borehole leaching was carried out with a chloride-hypochlorite solution. Molybdenum extraction on resin a was 85 % in 30 days. Experiments on the percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits confirmed the potential possibility of a significant increase in the extraction of uranium by electrophotoactivated percarbonate solutions relative to aqueous solutions of sodium and ammonium carbonate. When leaching with carbonate solutions without an additional oxidizing agent, the extraction of uranium from the Sugraly deposit ore sample was 52 and 59 % (sodium carbonate and ammonium carbonate). The use of hydrogen peroxide as an oxidizing agent made it possible to achieve 87-88 % extraction into pregnant solutions in 21 days without pre-oxidation. The performed studies confirm the processing capability of extracting uranium and molybdenum by percolation leaching in columns and borehole leaching.
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Date submitted2022-01-28
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Date accepted2022-04-26
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Date published2022-07-26
On the presence of the postmagmatic stage of diamond formation in kimberlites
- Authors:
- Sergey K. Simakov
- Yuri B. Stegnitskiy
On nowadays multiphase and the facies heterogeneity of the formations are distinguished at the study of kimberlite pipes. Most researchers associate the formation of diamonds only with the mantle source. To date, satellite minerals with specific compositions associated with kimberlite diamonds have been identified as deep mantle diamond association. They are extracted from the concentrate of the kimberlites heavy fraction and may reflect the diamond grade of the pipe. For some minerals in the diamond association, however, they can not be reliable. Some researchers also revealed shallow diamond associations, related to the formation of serpentine, calcite, apatite, and phlogopite. There is recent data on the formation of diamonds in rocks of the oceanic crust. In the last years microdiamonds were identified in chromites of the oceanic crust in association with antigorite formed at 350-650 °C and 0.1-1.6 GPa. As a result, the authors established a postmagmatic kimberlitic stage of diamond formation associated with secondary mineral associations based on the experimental and mineralogical data for the conditions of the shallow upper mantle and crust. Mineralogical and petrographic studies of Angolan kimberlite pipe show that antigorite is the indicator mineral of this stage.
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Date submitted2022-03-14
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Date accepted2022-05-13
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Date published2022-07-26
Unique titanium Deposits of Timan: genesis and age issues
The article critically analysesthe hypotheses about the formation, age, and sources of material of large Timan titanium deposits, which were previously considered ancient buried placers formed along the weathering crusts of the Riphean shales. We discuss an alternative hydrothermal-metamorphic hypothesis about the formation of these deposits and the source of ore material. It is established that the incoming zircon of different ages (570-3200 Ma), as well as two other geochronometers, rutile and monazite, underwent a thermal effect common for all varieties as a result of a hydrothermal process about 600 Ma ago. According to modern concepts, the closing temperature of the U-Pb system in rutile exceeds 500 °С, which suggests high-temperature conditions for the hydrothermal processing of rutile during the formation of the considered deposits in the Riphean.
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Date submitted2022-02-18
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Date accepted2022-05-25
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Date published2022-07-13
Remote sensing techniques in the study of structural and geotectonic features of Iturup Island (the Kuril Islands)
The article presents structural and geotectonic features of Iturup Island, the largest island in the Greater Kuril Ridge, a unique natural site, which can be considered as a geological reference. The structural and geotectonic analysis carried out on the basis of a comprehensive study of the new Earth remote sensing data, maps of anomalous geophysical geophysical fields, and other geological and geophysical materials using modern modelling methods made it possible for the first time to identify or clarify the location of previously discovered discontinuous faults, typify them and determine the kinematics, as well as to establish a more reliable spatial relationship of the identified structures with magmatism with the stages of the geological development of the region. The constructed diagram of the density distribution of the zones with increased tectonic fracturing shows a significant correlation between the distribution of minerals and weakened areas of the Earth's crust and can be used as an alternative method for predicting minerals in the study region, especially in remote and hard-to-reach areas. The presented approach can be extended to the other islands of the Greater Kuril Ridge, thereby bringing research geologists closer to obtaining the answers to questions about the features of the geotectonic structure and evolution of the island arc. The use of customized software products significantly speeds up the process of interpreting a large array of geological and geophysical data.
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Date submitted2021-06-22
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Date accepted2021-11-30
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Date published2021-12-27
Increasing the efficiency of rare earth metal recovery from technological solutions during processing of apatite raw materials
The issues of complex processing of mineral resources are relevant due to the depletion of available raw materials. So, it is necessary to involve technological waste, generated during the processing of raw materials, to obtain valuable components. In the process flow of apatite concentrate treatment using the sulfuric acid method, a large amount of phosphogypsum is produced with an average content of light rare earth metals (REMs) reaching 0.032-0.45 %. When phosphogypsum is treated with sulfuric acid solutions, a part of REMs is transferred to the sulfate solution, from which it can be extracted by means of ion exchange method. The study focuses on sorption recovery of light REMs (praseodymium, neodymium and samarium) in the form of anionic sulfate complexes of the composition [ln(SO 4 ) 2 ] – on polystyrene anion exchanger AN-31. The experiments were performed under static conditions at a liquid-to-solid ratio of 1:1, pH value of 2, temperature of 298 K and initial REM concentration in the solutions ranging from 0.83 to 226.31 mmol/kg. Thermodynamic description of sorption isotherms was carried out by the method based on linearization of the mass action equation, modified for the ion exchange reaction. As a result of performed calculations, the authors obtained the constants of ion exchange equilibrium for Pr, Nd and Sm, as well as the values of the change in the Gibbs energy for the ion exchange of REM sulfate complexes on the AN-31 anion exchanger and the values of total capacity of the anion exchanger. Calculated separation factors indicated low selectivity of AN-31 anionite exchanger for light REMs; however, the anion exchanger is suitable for effective recovery of a sum of light REMs. Based on the average value of ion exchange equilibrium constant for light REMs, parameters of a sorption unit with a fluidized bed of anion exchanger were estimated.
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Date submitted2018-12-28
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Date accepted2019-03-24
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Date published2019-06-25
Modern physicochemical equilibrium description in Na2O–Al2O3–H2O system and its analogues
Equilibrium and non-equilibrium states of systems Na 2 O–Al 2 O 3 –H 2 O and K 2 O–Al 2 O 3 –H 2 O are crucial for establishing key technological parameters in alumina production and their optimization. Due to a noticeable discrepancy between experimental results and thermodynamic calculations based on materials of individual researchers the necessity of systematization and statistical processing of equilibrium data in these systems to create a reliable base of their physicochemical state, analysis and mathematical modeling of phase equilibria is substantiated. The tendency to a decrease of the hydration degree of solid sodium aluminates with increasing temperature and the transition of systems from the steady state of gibbsite to equilibrium with boehmite is revealed. The paper contains approximating functions that provide high-precision description of equilibrium isotherms in technologically significant area of Na 2 O–Al 2 O 3 –H 2 O and K 2 O–Al 2 O 3 –H 2 O concentrations. Approximating function can be simplified by dividing the isotherm into two sections with the intervals of alkaline content 0-0.25 and 0.25-0.4 mole/100 g of solution. The differences in solubility isotherms for Na 2 O–Al 2 O 3 –H 2 O and K 2 O–Al 2 O 3 –H 2 O systems provide are associated with changes in the ionic composition solutions that depends on concentration and temperature, as well as differences connecting with alkali cation hydration, which is crucially important for thermodynamic modeling of equilibria under consideration.
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Date submitted2015-10-07
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Date accepted2015-12-27
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Date published2016-08-22
Phase transformations in synthesis technologies and sorption properties of zeolites from coal fly ash
- Authors:
- O. B. Kotova
- I. L. Shabalin
- E. L. Kotova
Coal fly ash is generated in the course of combustion of coal at thermal power plants. Environmental problems increase sharply without disposing that industrial waste. Technologies were tested of hydrothermal synthesis of zeolites from fly ash forming during combustion of coal at thermal power plants of the Pechora coal basin and dependences were identified of the experiment conditions on physical and chemical properties of the end product. It is demonstrated that synthesizing zeolites from fly ash is the first stage of forming ceramic materials (ceramic membranes), which defines the fundamental character (importance) of that area of studies. It was for the first time that sorption and structural characteristics and cation-exchange properties of fly ash from the Pechora basin coals were studied with respect to, Ba 2+ and Sr 2+ .
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Date submitted2015-07-07
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Date accepted2015-09-16
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Date published2016-02-24
Activation of heap leaching of low-sulfide ores the invisible gold
- Authors:
- A. G. Sekisov
- Yu. I. Rubtsov
- A. Yu. Lavrov
This article deals with a physical-chemical model of heap leaching processes justifying new technological approaches to recovering dispersed forms of gold from ores, placer sands and deute-rogene mineral raw materials. The key process of this model includes lattice diffusion of high-energy hydrion minerals and hydroxyl-radicals formed as a result of photochemical and electro-chemical processing of initial reagent aqueous solutions. Active components of gas-water emulsions obtained while processing initial reagent solutions provide a structural and material trans-formation of a mineral lattice which concentrates clusters of dispersed gold creating conditions for its interacting with complexing compounds of process solutions. The article also considers the technological processes of activation heap leaching of dispersed gold from the Pogromnoe ore field and the results of the experiments conducted in percolators with their charge ranged from 3 to 100 kg. The results have proved the efficiency of using gas-water suspensions prepared in the pho-toelectrochemical reactor with active ion-radical oxidizing agents.
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Date submitted2014-11-08
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Date accepted2015-01-27
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Date published2015-10-26
Geochemistry of ore-forming hydrothermal fluids of the World ocean
- Authors:
- C. M. Sudarikov
- M. V. Zmievskii
The most complete results of the study of hydrothermal ore-forming solutions geochemistry in the Russian and international expeditions to deep-sea hydrothermal fields of the world ocean are analyzed. Solutions of both high and low salinity with respect to seawater are formed in the discharge zone of fluids. Positive correlation of ore components with the chloride ion and negative one with the pH value may indicate the migration of components in acidic hydrothermal solutions in the form of chloride complexes. Hydrogen sulfide is associated with the significant positive correlation with metals, which indicates reducing conditions forming in ore-bearing hydrothermal solutions. This is confirmed by the close relationship of ore components with hydrogen. The transfer of metals mainly in the form of chloride complexes at high temperatures of the solution is confirmed by the results of our thermodynamic modeling. Methane is characterized by negative dependence on temperature and concentration of ore components, associated with positive dependence on pH and negative one on hydrogen sulfide. Each of the observed dependencies can testify against abiotic theory of income of methane in hydrothermal solutions. The following geochemical indicators are the most promising for the discovery of new ore deposits and the organization of geochemical monitoring during the development of already discovered fields: Eh, pH, Cl, Fe, Mn, H 2 S, CO 2 , H 2 and possibly CH 4 .
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Date submitted2014-11-04
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Date accepted2015-01-20
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Date published2015-10-26
Stability of productive well operation in a steam hydrothermal field
- Authors:
- A. N. Shulyupin
A condition of well operation stability based on agreement of indicator characteristics of well and aquifer throughput capacity is considered. Two hypotheses of the stability state are examined: with one and two possible combinations of characteristics. It is shown that taking into account resistance between the wellhead and the environment with constant pressure helps explain all the features of wellhead pressure and flow-rate relationship of steam-water wells based on the hypothesis with one combination (when the operating point is located on the ascending branch of a well characteristic). The throttling effect on the wellhead which was used in the development of the Mutnovka steam hydrothermal field in order to stabilize the well operation is explained.
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Date submitted2010-07-13
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Date accepted2010-09-25
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Date published2011-03-21
Hydrogeological typisation of the north part of the Mid-Atlantic ridge
- Authors:
- M. V. Krivitskaya
The deep basite-hyperbasite rocks wich are special features for the north part of the Mid-Atlantic Ridge (MAR) are observed. The hydrogeological structures of the MAR are distinguished.
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Date submitted2010-07-20
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Date accepted2010-09-04
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Date published2011-03-21
Forming of the composition of hydrotermal solutions in hydrogeological massifs of ultrabasic rockes of the Mid-Atlantic ridge
- Authors:
- S. M. Sudarikov
- M. V. Krivitskaya
Difference in structural position and influence of ores from different types of sediments on the geochemical characteristic of ores are observed. Results of end member composition correlation analysis show negative link of H 2 S with CH 4 и Н 2 .
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Date submitted2009-09-21
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Date accepted2009-11-10
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Date published2010-06-25
Simultaneous doping of silicon carbide with aluminum and nitrogen
- Authors:
- I. I. Parfenova
Three atomic shell cluster of SiC is treated as a set of chemical bonds with tetrahedral coordination. Chemical bonds energies are determined in tight binding approximation taking into account second neighbors interaction and relaxation of atomic positions. Correlations in behavior of Al and N atoms in Si-C-Al-N system determine the quasibinary character (SiC) 1-x (AlN) x alloys. Inhomogeneous regions in (SiC) 1-x (AlN) x system were evaluated using the condition of mixing free energy minimum. We assumed that doping does not change the vibration spectra of the crystal.
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Date submitted2009-07-05
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Date accepted2009-09-25
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Date published2010-04-22
Active methods for control of geomechanical state of rock mass in coal deposit mining under complicated geological-and-mining conditions
- Authors:
- F. N. Voskoboev
- Yu. A. Semenov
- V. A. Zvezdkin
The paper presents the main technologies, characteristics, schematic diagrams and parameters of active methods for control of geomechanical state of technogenic rock mass, domain and technical-and-economical efficiency of their industrial application.
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Date submitted2008-10-13
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Date accepted2008-12-28
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Date published2009-12-11
Ore-forming hydrothermal solutions and gas hydrate formation in the ocean
- Authors:
- S. M. Sudarikov
- S. S. Filatova
Geological and tectonic settings and thermobaric characteristics of hydrothermal activity are confronted with those of gas hydrate formation. Hydrocarbon concentrations and isotopic composition in hydrothermal fluids of mid-ocean ridges with different thickness of sediment cover and marginal oceanic basins are compared. The possible influence of rising thermal fluids on gas hydrate accumulations was analyzed and examples of hydrate formation linked with hydrothermal process are given.