Ukrainian Deposits Research Articles

FLUORIDE IONS REMOVAL EFFICIENCY OF NATURAL/ACTIVATED ZEOLITE AND BENTONITE SORBENTS

Addressing the health concern of fluoride ions contamination in water, that cause such deceases as dental and skeletal fluorosis, requires the development of effective adsorption materials for water treatment. Our research objective was to evaluate the adsorption properties and capacities of zeolite and bentonite, sourced from Ukrainian deposits, and their acid-activated forms in relation to fluoride ions and estimate fitting this data to various adsorption models. Characterization of natural and acid-activated zeolite and bentonite sorbents was performed through X-ray diffraction to determine the phase composition of these substances. Adsorption experiments were carried out at different initial fluoride ions concentrations (3, 5, 10 and 15 mg/l) and pH (3.7; 7.5). Acidification (changing pH from 7.5 to 3.7) increase adsorption capacity of natural zeolite and bentonite more than twice. It was found that natural zeolite removes fluoride ions at the level of 67 % at pH 3.7 and a high dosage of sorbent – 10 g/l and an initial concentration of fluoride ions – 5 mg/l, while its acid‑activated form was more effective - the removal of fluoride ions is 86 % at a lower dosage of sorbent – 1 g/l. Similarly, natural bentonite demonstrated a maximum removal efficiency of 45 % at pH 3.7 and a dosage of sorbent – 10 g/l, and its acid-activated form allowed for the removal of fluoride ions of about 83 % at a dosage of sorbent – 2 g/l at the same fluoride ions concentration. It is shown that the Vagelar-Langmuir (VL) isotherm model is the most accurate for describing the process of fluoride ions adsorption by acid-activated forms of natural sorbents, where the R² values are close to 0.999, indicating monolayer adsorption on homogeneous active centers. The obtained results indicate the greater efficiency of acid-activated forms of natural sorbents and the prospects of their use for the removal of fluoride ions from water.

INFLUENCE OF CLAY MINERAL ADDITIVES ON THE PROPERTIES OF COMPOSITE WATER–COAL FUEL.

The study aimed to examine the electrokinetic and rheological properties of composite water-coal fuel (CWCF) based on anthracite and P-grade coal in the presence of clay mi­nerals. The influence of clay mineral additives on the electrokinetic and rheological properties of CWCF was studied. The clay minerals used were montmorillonite, illite, and kaoli­nite from Ukrainian deposits. The fuel was prepared based on P-grade coal and anthracite. The share of the solid phase (coal) in the suspensions was 62 %. According to the particle size distribution, the bulk of the coal has a size of 30–110 μm with a bimodal distribution. To obtain the CWCF, the coal powder was homogenized with the dispersion medium by wet grinding in a ball mill for 20–25 minutes. The dispersion medium was distilled water. Wet grinding was carried out until particles < 0.25 mm in size were obtained. We obtained a CWCF with a concentration of 62% of the so­lid phase of coal. Additions of chemicals were not practiced to study the effect of clay mine­rals in a pure experiment. Clay minerals were added at a concentration of 0.5–3 % by weight of the CWCFs. Their rheological data were measured using a Rheotest-2 rheometer at a temperature of 20 ºC and the shear-stress/shear-rate data for the CWCF covered a range of 0.1 to 470 s-1. The sedimentation stability of St was stu­died at the time of stratification of the CWCF sample in a measuring cylinder. After preparation, a 10-mL sample of the CWCF was placed in a 25-mL glass cylinder. St is equal to the time of the beginning of the suspension stratification in days. It was established that ξ - the potential of CWCF particles with the addition of clay mine­rals shifts to the negative region and reaches – 45–50 mV at pH>8. Montmorillonite was found to be most effective additive for controlling the properties of the CWCF. Systems with clay mineral additives demonstrate a pseudoplastic type of flow in the range of shear rates γ 0–100 s-1 and a Newtonian type of flow at higher γ. According to their effect on the increase in apparent viscosity, clay mine­rals are arranged in the following order: kaolinite, illite, and montmorillonite. The thixotropic properties of the studied systems provide complete restoration of the properties of the CWCF when the shear rate is reduced to 0–40 s-1. Sedimentation stability in the presence of illite and montmorillonite additives reaches 8–14 days. In contrast to illite and montmorillonite, kaolinite has a very weak effect on the properties of CWCF.

Peculiarities of high-temperature refining of carbon materials

The purpose of the study was to determine the influence of the main following factors on the efficiency of the process of high-temperature refining of natural and artificial graphite: processing temperature, distribution of metal oxides, and changes in the aggregate state of ash impurities. Thermal processing of natural graphite from Ukrainian deposits and anthracite from Donetsk coal basin was carried out in a chamber furnace at a holding time of 10–20 minutes in a temperature range of 1500–30000С. The quality of refining was carried out by ICP-OES and XRF analysis methods. It was established that the refining process may be divided into three following periods: 0–16000С (removal of moisture, volatiles, and decomposition of carbonates); 1600–26000С (evaporation of main ash-forming metals Fe, Si, Al, Ca, Mg in the form of oxides, silicides, and carbides); and 2600–30000С (evaporation of refractory compounds Ti, V, Mo, the content of which in the initial raw material determines the processing temperature and the quality of the final product). The distribution of metal oxides in the initial carbon material is not uniform, which complicates the use of equilibrium state models. The transition of ash into the liquid and then gaseous state has a significant impact on the result of heat treatment. This is what determines the choice of the process scheme. Intermittent process is the heating by an external heater in an inert gas environment. Continuous process is the heating of the material in moving containers or processing in an electrothermal fluidized bed.

Regeneration of deposits of hydrocarbon fields of Ukraine

Formulation of the problem. In the world's oil and gas-bearing basins, there are known examples of an increase in the reserves of hydrocarbon deposits as a result of inflow of fluids from the deep subsoil. Recently, the theory of the Earth degassing is gaining popularity. There are more and more arguments in favor of the fact that in many oil- and gas-bearing provinces of the world, oil and gas deposits are constantly replenished due to the migration of hydrocarbons through degassing pipes. Certain prospects for maintaining oil and gas production are possible as a result of the natural recovery of depleted deposits in Ukraine as well. However, this issue has not been sufficiently studied and requires further research. The purpose of the article is to argue with actual materials for the regeneration of hydrocarbon deposits, to estimate the probable volumes of their replenishment, to determine the methods of geological research to outline the zones of nourishment of hydrocarbon deposits. Materials and methods. Research materials are actual materials from the development and permanent assessment of hydrocarbon reserves of Ukrainian deposits. The research methodology consists in the analysis of the facts of the replenishment of hydrocarbon deposits from the point of view of new scientific concepts of the supply of hydrocarbons from the deep subsoil. Results. Based on the results of the increase in reservoir pressures of spent gas condensate deposits and repeated calculations of hydrocarbon reserves of the Shebelynka, Chornukhy, Bilousivka and Proletarka deposits of the Dnipro-Donets Basin, a conclusion was made about the replenishment of deposits due to the vertical migration of oil and gas, the probable scales of deposit regeneration were estimated. The results of industrial development of the East Kazantyp and North Bulganak gas fields of the Indolo-Kuban depression also testify to their probable feeding from the depths. Adiabatic fracture formation associated with seismotectonic impulses and phenomena of natural rupture of rocks by deep fluids plays a significant role in the formation of unconventional deposits. The result of fluid fracturing of rocks is specific matrix microcracking. It is well manifested in well cores from depths of more than 5.5 km (Semyrenky, Machushy deposits of the Dnipro-Donets Basin). Hydrocarbon deposits at these depths have a zonal character and are not controlled by the structural factor. Scientific novelty, practical significance and recommendations. Actual materials have proven that some hydrocarbon deposits in Ukraine are constantly being replenished as a result of seepage of deep fluids. It is likely that the main channels of hydrocarbon supply to deposits are deep faults. To determine the degassing channels it is advisable to use the methods of field geophysics and geochemical studies. We can state that the replenishment of gas reserves of some Dnipro-Donets Basin fields according to confirmed facts ranges from 14 to 1800 million m3 annually. It is necessary to monitor the spent deposits, therefore it is advisable not to liquidate decommissioned wells, but to preserve them or transfer to the fund of observation wells, periodically measuring reservoir pressures and determining the character of fluid saturation of spent deposits. It is necessary to manage the process of extraction of hydrocarbons, applying a policy of balanced economical production.

Investigation of Petroleum Bitumen Resistance to Aging

Aging peculiarities of paving bitumen, which was obtained by different ways, have been studied. Oxidized and residual bitumen produced from oils of Ukrainian deposits were used and the changes in the main characteristics of bitumen after 5 and 10 h of aging in a thin film at the temperature of 436 K have been determined and the processes occurred during the aging have been studied. Using infrared spectroscopy, the changes in the structural composition of the binder during aging have been analyzed.

Study of surface and rheological properties of clayless biopolymer drilling mud treated with M-1 surfactants

An important issue of improving the quality of the initial opening of the reservoir through the use of a system of drilling fluids treated with surfactant M-1. For high-quality disclosure, it is proposed to use clay-free biopolymer drilling mud. The main analyzed features of M-1 use as an additive to biopolymer drilling mud used in Ukrainian deposits. The formulation is substantiated and the study of clay-free biopolymer solution for primary opening of productive layers is carried out. Processed non-ionic surface active agent (surfactant) M-1 model biopolymer clayless drilling mud. With the use of oil (density 838 kg /m3) Kachanivsky oilfield conducted measuring the interfacial tension coefficient at the interface "mud filtrate – oil" stalagmometric metod by changes in the concentration range (% by weight) M-1 from 0 to 5. The influence of M-1 concentration on the interfacial tension coefficient at the interface of "oil – biopolymer drilling fluid filtrate" is shown and the critical concentration of micelle formation (CCM) of surfactant in the filtrate is found, the excess of which does not reduce the interfacial tension. It has been experimentally established that with increasing concentrations of M-1, the interfacial tension factor at the interface between the phases of "oil – filtrate of the drilling fluid" is sharply reduced, which leads to an increase in the formation fluid formation fluid. The rheological properties of drilling fluids with rotational viscometry are determined. Polynomial dependences of temperature influence on rheological properties without clay biopolymer drilling mud have been established.

In Ukrainian

Man-caused load on sources of industrial and domestic water supply, which causes the discharge of insufficiently treated wastewater, is one of the great environmental problems in Ukraine. The traditional way of solving this problem, associated with the disposal of such waters by adsorption, membrane or catalytic technologies, has a number of disadvantages associated with large volumes and a wide range of pollutants, traditional methods often require preparatory measures, time-consuming, scarce materials and expensive equipment. It would be ideal to create waste-free circulating water supply technologies, but these options are still far from being mass-produced. A promising way to solve these problems is to organize such production cycles, where the disposal of toxic wastewater will be combined with recovery technologies. Industrial and domestic wastewater often contains a significant proportion of the organic component. These are oil products, by-products of organic synthesis, spent lubricating and cooling suspensions, waste from the food, alcohol and pulp and paper industries, dyes and pigments, etc. All this waste is energy saturated and can be separated and used as fuel. However, due to low concentrations in most wastewater, their separation is economically unprofitable. A method is proposed for neutralizing toxic organic wastewater by using it as a dispersion medium for composite coal-aqueous fuel (CAF). The possibility of priming carbon microparticles obtained by preliminary plasma-chemical treatment of an organic dispersion medium to stabilize composite coal-water fuel were investigated. Waste cutting fluid (JCL) was used as an organic dispersion medium; anthracite served as the dispersed phase. A CAF sample was obtained based on anthracite from Ukrainian deposits with a solid phase (W) content of 70 mass. %, and studied its electrokinetic and rheological properties. It has been found that the preliminary plasma-chemical conversion of organic wastewater used as a dispersion medium for composite water-coal fuel significantly improves the operational properties of CAF. The growth of sedimentation stability and the optimization of the effective viscosity are achieved mainly through the implementation of the structural and mechanical factor by increasing the number of contacts with the introduction of a highly dispersed fraction of carbon microparticles and increasing the electrostatic repulsion of the elements of the suspension structure. Thus, the sedimentation stability of the obtained CAF is significantly improved in comparison with conventional anthracite suspensions in organic wastewater and reaches 2 days without the addition of stabilizers. In the future, it is planned to further improve the properties of CAF by introducing stabilizing reagents and dispersants into its composition.

Co-firing of gas coal dust fine particles and synthetic peat gas. Part 1. Simulation of processes of steam-air gasification of peat in a fixed bed and combustion of dust and gas mix in a stream

Purpose. To build a model of solid fuel gasification in a fixed bed taking into account the velocity of particles, which allows obtaining detailed information about the technological process. To develop an optimal technological scheme of co-firing of pulverized coal particles and peat gas in the TPP-210A boiler. To investigate the process of a binary mix burning. Methodology. The objects of research were pulverized coal of Ukrainian deposits and peat from Volyn region deposits. The developed model was used to calculate the peat gasification process. To study the process of burning a binary blend, ANSYS FLUENT package was used. Findings. A model of solid fuel gasification in a fixed bed has been developed, which differs from the existing models by taking into account the particle velocity and its change. With the aid of this model the detailed information on temperature and concentration fields of the two-phase environment is received. The process of burning binary mix in a TPP-210A boiler is investigated. Originality. It was found that in the time interval 2200 < < 3200 s a stable stationary process of thermochemical processing of peat with q4.1 = 0.130.3% is formed. The profile of the dispersed phase velocity distribution resembles a mirror reflection of the profile of the particle diameter dependence. Practical value. Using the constructed model, the process of thermochemical processing of 28939 kg/h of raw peat in three reactors with a fixed bed at a pressure of 1.5 MPa was numerically investigated. The composition of the generator gas at the reactor outlet was determined.

Research into phosphate mineral composition and waste phosphorite ore

Purpose. Theoretical and experimental studies of chemical and mineral composition and the structure peculiarities of phosphorites from Ukrainian deposits to define the degree of their suitability for other industries. Methods. The ore chemical composition was determined by conventional (wet) analysis using standard certified chemical reagents. The mineral composition was studied on the scanning electron microscope equipped with the attachment for the energy-dispersive electron microprobe analysis (EMPA) with the software for calculating the chemical composition of the studied sample microvolume. The petrographic analysis was carried out by the traditional methods of microscopic section preparation with subsequent identification and description of the minerals. The microscopic study of the original ore samples aimed at their mineral composition determination was conducted on the Nu optical microscope (Germany) both in transmitted and reflected light. The thin and polished sections prepared using the standard technology were used as samples. In the laboratory environment, the phosphorites were subjected to magnetic dressing in magnetic fields with different intensity. The experiments in the weak field were modelled with the help of the magnetic analyzer while the experiments in the strong magnetic field were modelled on the rotor separator. The flotation dressing method was studied on the laboratory mechanical flotation machine. Findings. It was found that phosphate nodules are rounded mineral formations of irregular shape; they consist of sand bound with the yellow-brown phosphate cement. Ore useful substance is a phosphorus-bearing mineral that by the element chemical composition corresponds to fluorocarbon-hydroxyl-apatite with the dominant content of Ca (45.23%), P (15.67%), and B (27.87%). The results of the integrated petrographic study of the phosphorite samples from the ore body of “Peremoha” area are presented. Originality.The study has revealed that phosphorus-containing substance in the phosphorite samples is the mass that cements barren minerals (mainly quartz, glauconite, calcite and plagioclase). Practical implications. According to the phosphate content level, the phosphorites from Malokamyshevatske, Iziumske and Sinichino-Yaremovske deposits can be treated as minerals for ferrophosphorus smelting. Keywords: ferrophosphorus, ore substance, phosphorite, mineral varieties, petrography, apatite

Rubber Crumb Modified Bitumen Produced from Crude Oils Residuals of Ukrainian Deposits

Rubber Crumb Modified Bitumen Produced from Crude Oils Residuals of Ukrainian Deposits

Dependence of Ukrainian economy on industrial import and prerequisites of forming effective industrial specialization

Актуальность темы исследования обусловлена углублением деиндустриализации украинской экономики и ее импортозависимости. Ключевым признаком высокой импортозависимости служит большой дефицит баланса внешней торговли товарами, который существует уже длительное время. В статье рассматриваются теоретические основы исследования импортозависимости экономики. Также представлен обзор современных реалий политики импортозамещения, применяемой в разных странах. Основным источником информации для исследования послужили статистические данные таблиц «затраты-выпуск». Уровень зависимости украинской экономики от импорта промышленных товаров оценивался по направлениям его использования - в промежуточном и конечном потреблении, валовом накоплении основного капитала. Расчеты показали, что значительную часть функций по обслуживанию потребительского и инвестиционного рынка выполняют иностранные производители, тогда как обрабатывающий сектор страны в основном занят производством промежуточной продукции, которая остается еще и основой его экспорта (металлы, сырьевые минеральные продукты, древесина и изделия из нее, неорганическая химия). Анализ уровня зависимости от импорта различных видов производства перерабатывающей промышленности показал, что на внутреннем рынке товаров промежуточного потребления с недавних пор закрепилось абсолютное преимущество импорта, особенно продукции химической отрасли, машиностроения, легкой промышленности. В результате исследования обоснован вывод, что приоритетными видами деятельности (в контексте эффективной производственной специализации) выступают те, которые имеют высокий уровень межотраслевых производственных связей. Такая роль подходит прежде всего машиностроению и химической промышленности. Другой предпосылкой удачного импортозамещения служит диверсификация экспорта на основе модернизации производства в отраслях перерабатывающей промышленности. Также необходимо создание инновационных промышленных кластеров сетевого типа, в которых производственные компании и исследовательские организации объединены в совместном научно-производственном процессе. Развитие сырьевой базы и добычи полезных ископаемых из украинских месторождений также будет способствовать самообеспечению экономики и переходу к эффективной производственной специализации.

Studies of the basics of technology for optimal design of rational use of valuable mineral deposits

The aim of this paper is to develop and validate methods of choosing the means of valuable mineral deposits. This paper describes a methodology for assessing deposits from both an economic and an environmental point of view. The questions of creation of modern mathematical support, as well as the means of decision making for the feasibility study of Ukrainian deposits with valuable minerals and determination of the optimal strategy for their development are considered. A new way of developing environmental scenarios for territorial development is proposed, which is to optimize network models that are consistent with environmental strategies for mineral exploration with a view to producing the final products. Unlike economic scenarios, the development of the field of environmental requirements takes into account the rating of man-made environmental hazards at each stage, which allows not only the benefit but also the risks of production. An algorithmic description of the process of managing the state of reserves and the form of presentation of the results make it possible to introduce the described methods into production, at the same time the field is considered not as a separate object, but as an intermediate element in the process of obtaining final products. In addition, the sequence of finding the optimal solution can be considered as from the beginning of development of the field to the stage of obtaining the final products, and in the opposite direction.
 The field of optimal design technology for the rational development of fields is independent of the type of minerals, since the determination of the optimal scenario of production of final products for a particular field is due to the model of changing the state of mineral reserves from balance sheet to final products, which after the transformation of acyclic graphs in the network can be optimized using classic algorithms.

MACROECONOMIC DYNAMICS FORECASTING

Steady economy growth is possible only after allocating a clear objective and building macroeconomic development model. Acquiring of accurate prognoses of future development is the primary objective of applying macroeconomic models. Before VAR methods emerged prognosis were made based on timeline of economic indicators that were acquired through singular spectrum prognosis methods and extrapolation. Applying SSA methods implied that an indicator under research was formed under the influence of a multitude of factors that were impossible to separate. In this case, indicator changes were connected with the time flow rather than with the influencing factors, which led to the creation of singular time series. Authors prove that Ukrainian economy faced steady developing as well shocks. That is why using simple regressions for prognosis of macroeconomic indicators is not sufficient. VAR models not only enable the accurate forecasting of macroeconomic indicators but also are very useful when building models of stress-testing of the economy and banks in case of external and internal shocks. Preventing the negative effects can be effective using a model of macroeconomic risk management that enables managing exogenous macroeconomic factors in order to attain the well-defined objectives. In this paper, authors present the dynamics analysis of yearly changes of the gross domestic product, consumer price level, USD/UAH exchange rate, M2 money supply indicator, assets and liabilities of the Ukrainian banks dynamics, Ukrainian deposits, banks capital dynamics. Keywords: macroeconomic model, VAR model, macroeconomic risks, timeline, inflation rate, money supply, gross domestic product.

Effect of Both the Phase Composition and Modification Methods on Structural-Adsorption Parameters of Dispersed Silicas

Tripoli from two Ukrainian deposits was studied in its natural and modified forms. The investigation of natural and modified tripoli involves the identification of their phase compositions through X-ray diffraction and the analysis of their water vapor adsorption-desorption isotherms. The obtained results are evidence of changes in the structural-adsorption parameters of tripoli as a result of modification. Their treatment in boiling water or acid causes apparent alterations of contents of the main phases and sizes of their crystallites, whereas their calcination causes not only the dehydroxylation of surfaces and the agglomeration of phases, but even phase transformation in the case of carbonate tripoli. After analyzing water vapor adsorption-desorption isotherms of natural and modified tripolis, some correlations between their adsorption parameters, phase compositions, main phase contents and crystallite sizes have been found.

‘Hardcastle Hollows’ in loess landforms: Closed depressions in aeolian landscapes – in a geoheritage context

Abstract Loess landscapes sometimes contain isolated depressed areas, which often appear as lakes. The outline shape (and distribution) of these depressions could be controlled by random processes, particularly if the depressions are caused by loess hydroconsolidation and ground subsidence. By applying the Zingg system of shape classification it is possible to propose a mean random shape for the closed depressions. A Zingg rectangle with a side ratio of about 2:1 is produced by a very simple Monte Carlo method, which had been used previously to calculate the mean random shape of a loess particle. The Zingg rectangle indicates the basic shape of the mean closed depression. A simple four stage process for the formation of the depressions is proposed. They might be called ‘Hardcastle Hollows’ in honour of John Hardcastle who first reported them, in New Zealand. Studies on Ukrainian deposits suggest that there might be some stratigraphic value in the observation of closed depressions; they are often not superimposed in successive depositions of loess. Hydroconsolidation is important in landscape processes. The hollows provide interesting habitats and enlarge the ecological interest of loess deposits; the geoheritage scene is enhanced.

Weakening of rock strength under the action of cyclic dynamic loads

We report results of experiment on the estimation of decreasing strength of natural stone exposed to repeated dynamic loading. The study was conducted in order to assess the feasibility of using natural stone for the accompanying extraction of stone blocks under conditions of gravel quarries. We examined samples from 13 Ukrainian deposits of natural stone. The stresses were created by a weight dropped on the tiles made of natural stone. The damage was evaluated using the ultrasonic device UK-14MP. The established resistance of rock to repeated impact actions showed that at a low specific energy of the impact (1.47‒2.7 kJ/m 3 ) there are the granites (Zhezhelivski, Tokivski, Koretski deposits) that are almost not destroyed. These very deposits are suitable for the accompanying extraction of blocks of natural stone under conditions of gravel quarries. Building structures from these fields can be used in facilities and buildings that are exposed to vibration. Depending on the energy capacity of destruction, we conditionally divided natural stone into three groups. By applying a nondestructive control, we found that granites lose their strength prior to destruction from 11.6 to 41.5 % because of anthropogenic microcracking. The fatigue strength of granites is affected by the content of quartz; an increase in quartz results in increasing strength. It is demonstrated that the texture of granite exerts not a less impact on the strength of the stone; an increase in grain size in granite leads, despite a considerable content of quartz, to a decrease in the stone fatigue strength. Increasing accessorial minerals in granites leads to a decrease in fatigue strength

Substantiating the criteria for applying selective excavation of coal deposits in the Western Donbass

The provision of the energy system of Ukraine with a stable supply of coal in the long term demands calculation of the capacity of the exploitable deposits. Ukrainian deposits are characterized by insignificant thickness and complicated mining-geological conditions, which significantly complicates the mining process. Therefore, it is necessary to develop and use new energy-efficient technologies of coal mining. The article evaluates the criteria of usefulness of thin layers of deposits in the Western Donbass, which contains 25 bn t of coal, i.e 21.3% of total resources of the country, for processing in selective technology. According to the geologicstructural factor, we distinguished the fields of mines of hydrodynamically “open” and “close” types, the water inflows of which differ by a factor of ten. Taking the example of the mines of the east group, we ascertained the potential of the most promising coal reserves, which are appropriate for mining using selective technology. It was established that in these conditions, selective technology of coal excavation would not only allow a decrease in the ash content of the coal output, but would also prolong the period of the industries` operation. Backfilling of mined-out areas decreases the technogenic load on the underground and surface hydrosphere, decreases the subsidence of the surface and the volume of waste rocks.

INVESTIGATION OF STRUCTURAL FEATURES OF NATURAL AND ENRICHED KAOLINS OF THE REPUBLIC OF BELARUS

IR-spectroscopic results of study of primary kaolins of the Belarusian deposits «Sitnica» and «Dedovka» in a natural state and enriched by hydraulic sieve method are presented. The structural features of Belarusian kaolins as compared with known high-quality kaolin of Ukrainian deposits «Prosyanovskoe» are revealed, the values of crystallinity index are determined. Analysis of IR-spectra in the high-frequency region allowed us to establish the water connection forms in natural and enriched kaolins, the presence of OH-groups in the interlayer space, inside and on the surface of the octahedral layer and adsorbed water molecules, which can affect the rheology of kaolin suspensions. Silicate absorption band of kaolin, as well as intense peaks of deformation vibrations of quartz, typical for unenriched natural kaolin of Belarusian deposits, are in the lowfrequency region. Investigation using IR-spectroscopy made it possible to establish the structural features of natural kaolins related to the presence in the primary kaolin of the «Sitnitsa» and «Dedovka» deposits of the mineral of the kaolinite group of dikkite. The crystallinity index values (according to Hinckley) are established for natural and enriched kaolins «Sitnica» (0.94 and 1.11) and «Dedovka» (0.98 and 1.04) in comparison with kaolins of Prosyanovskoye deposit (1.31).

Some features of Pd(II) and Cu(II) adsorption on bentonites

Copper(II) and palladium(II) adsorption from single-component, Cu(NO3)2 or K2PdCl4, and two-component Cu(NO3)2-K2PdCl4 aqueous solutions by bentonites provided by two different Ukrainian deposits was investigated in this study. As was found, types of the obtained adsorption isotherms depended on the bentonite origin, the nature of the adsorbed metal ion and the component quantity in the aqueous solutions under study. The most complicated adsorption isotherms were obtained for Pd(II) adsorption from the single-component Pd(II) and two-component Pd(II)-Cu(II) solutions. The adsorption of each metal ion decreased in the presence of the second one being evidence of competitive adsorption and confirming the nonhomogenity of adsorption sites.

ADSORPTION AND PHYSICOCHEMICAL PROPERTIES OF NATURAL MONTMORILLONITES AND THEIR MODIFIED FORMS

The data, earlier published and obtained by us, concerning an influence of various factors on physicochemical properties and structural parameters for montmorillonites of different origin are summarized. Some regularities of water vapor ad/desorption by bentonites depending on their origin and activation method as well as the nature of metal cations have been revealed. The data concerning the influence of a hydration degree of bentonites on a value of basal spacing, d(001), in montmorillonite are presented and analyzed. Ad/desorption properties towards water vapor in the case of natural bentonites from three Ukrainian deposits, i.e. Gorbskoe (Bent(G)), Dashukovskoe (Bent(G)), and Kirovogradskoe (Bent(K)), as well as for their modified forms, i.e. H2O-Bent (obtained by bentonite boiling in distilled water for 1 h), 300-Bent (obtained by bentonite calcination at 300 °C for 1 h), and 1H-Bent-1 (obtained by bentonite boiling in 1 M HNO3 for 1 h), have been systematically investigated. It has been found that values of a monolayer capacity, аm, for natural bentonites decrease in the order NBent(D) > N-Bent(G) > N-Bent(K). It is interesting to note that аm slightly increases after the acid modification of bentonites and significantly decreases in the case of supporting Pd(II) and Cu(II) complexes on them. Values of a specific surface area for natural bentonites and their modified forms determined as a result of both water vapor adsorption-desorption and thermal argon desorption are presented and they are significantly varied depending on the bentonite origin. Values of an activity of water adsorbed on natural bentonite, аH2O = P/Ps , determined from the water vapor isotherms at the same adsorption value increases in the order N-Bent(D)< N-Bent(G) < N-Bent(K). The same orders are observed for the bentonite samples after both their acid treatment and anchoring Pd(II) and Cu(II) ions on their surfaces.