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EN
It is necessary to exploit an easy and effective way to obtain flotation collector. In this paper, oleic acid was modified by oxidation reaction to obtain an excellent collector. The flotation performances of oleic acid and its oxidation products were systematically investigated and a novel collector ((E)-8,11-dihydroperoxyoctadec-9-enoic acid, EDEA) was obtained. Single mineral flotation tests results showed that EDEA had strong flotation power towards quartz at pH>11 and hardly floated hematite and magnetite at pH=8~13. The recovery of quartz could achieve 92.35% with 120 mg/L EDEA under the condition of pH=12 and dosage of CaCl2 60mg/L while the recovery was 62.44% with 120 mg/L oleic acid. Bench scale flotation tests results showed that EDEA had a preferable effect on separating quartz from iron ore especially at low flotation temperature (288K). The mechanism research revealed that EDEA attracted on quartz surface through electrostatic attraction and the neighboring EDEA molecules could form intermolecular hydrogen bonds which resulted in a closer alignment of EDEA on quartz surface.
EN
Quartz and feldspar are usually exist in symbiosis in nature, and they are difficult to be separated effectively by conventional physical methods owing to their similarities in crystal structures and surface characteristics. Flotation is the most resultful method, and especially, flotation with hydrofluoric acid (HF) is the most efficient way. Because HF may cause serious environmental and health problems, the effective and environmentally friendly separation of quartz and feldspar remains a formidable challenge. The crystal structure, surface broken bonds, surface energy, and solid–liquid interface properties of quartz and feldspar are investigated in this paper. In particular, some types of mixed cationic/anion collectors and their interaction mechanism on the quartz and feldspar surfaces with acidic, alkaline, and neutral media in the absence of fluorine are discussed, and the grade and scheme of quartz and feldspar for the practical application are illustrated. This review proposes concrete research approaches and provides perspectives for the advanced processing of quartz and feldspar in an environmentally friendly and economical way.
EN
A quaternary ammonium salt, N, N-bis (2-hydroxyethyl)-N-methyl dodecyl ammonium chloride (BHMDC), with high surface activity, was screened and firstly introduced in the reverse flotation of hematite ores based on Density Functional Theory (DFT) calculation and surface tension measurement. The interaction mechanism of BHMDC on the surfaces of quartz and hematite was studied by zeta potential measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transforms infrared spectroscopy (FTIR), respectively. The results of DFT calculation and surface tension measurement indicated that BHMDC had higher selectivity and hydrophobicity than dodecylamine (DDA). The analyses of zeta potential measurement, FTIR, and XPS demonstrated that the adsorption of BHMDC on hematite and quartz surfaces were mainly dependent on hydrogen bonding and electrostatic interaction. Due to the more active sites (O atoms), the weaker charge and larger size of polar groups, BHMDC had better simulation results in performance than DDA, especially in selectivity. The flotation tests showed that BHMDC exhibited better flotation performance, which was consistent with the results of DFT calculation. And the efficient separation of hematite and quartz within the wide pH value range (4.0-10.0) was determined, which was also confirmed by zeta potential measurement. It also indicated that BHMDC was an excellent collector in the reverse flotation of hematite ores with great industrial potential, which could obtain the concentrate with the Fe grade of 65.37% and recovery of 88.92%
EN
Land surface emissivity retrieval is important for the remote identifcation of natural materials and can be used to identify the presence of silicate minerals. However, its estimation from passive sensors involves an undetermined function related to radiance data, which is infuenced by the atmosphere. We tested three methods for temperature emissivity retrieval in a dune feld composed of 99.53% quartz (SiO2) using Advanced Spaceborne Thermal Emission and Refection Radiometer (ASTER) imagery. The tested methods were the reference channel method (RCM), emissivity normalization method (ENM), and temperature emissivity separation (TES) method. An average quartz reference spectrum for the dune samples was calculated from an emissivity database based on temperature and used to evaluate the emissivity products of four ASTER images. In general, the three tested methods had a good approximation when analysed the emissivity reference curve, especially for longer wavelengths that ranged between 2 and 4% of emissivity. The RCM and ENM produced very similar results with the coefcients of determination (R2 ) as 0.9960 (RMSE 0.0184) and 0.9959 (RMSE 0.0185), respectively. RCM method presented superior results (R2 : 0.9960, RMSE: 0.0184), compared to the TES method (R2 : 0.9947, RMSE: 0.0197). The TES method showed good results only for shorter wavelengths and, hence, to identify specifc targets using ASTER data, such as silicate minerals, it is better to use the RCM method. The emissivity value selected at the saturation point of the spectral library based on temperature is fundamental in acquiring more reliable data.
EN
Three-point bending. Abstract This work is an experimental approach for the development and characterization of a polymer concrete reinforced with natural fibers. The polymer concrete consists of sand (Quartz) and orthophthalic polyester used as a binder. Marble powder was used to ensure the continuity of the particle size of the granular mixture. As reinforcement, 2% of chopped date palm fibers (short, very short or mixed) were added. For comparison, identical polymer concrete flexure specimens reinforced with the same content of short E-glass fibers were also prepared and tested. All specimens were initially cured at room temperature and then post-cured for 6 h at 70°C. The results of three-point bending on smooth specimens with different rates of charges (marble), showed that the flexural and compressive strength were improved by adding 20% of marble, and were 31.80 MPa and 67.42 MPa respectively. The flexural strength of specimens showed that the improvement or the degradation of polymer concrete properties seemed to be attributed to the nature of fibers (treated or untreated), and/or to the fibers sizing (short, very short or mixed).
PL
W pracy przedstawiono wyniki badań reaktywności krajowych kruszyw z wybranych, litych skał osadowych przy wykorzystaniu nowych metod badawczych wdrożonych w dokumentach technicznych Generalnej Dyrekcji Dróg Krajowych i Autostrad (GDDKiA), zgodnych z metodami RILEM i ASTM. Zakres badań obejmował kruszywa grube łamane o potencjalnej przydatności do wykonania wytrzymałego i trwałego betonu, wyprodukowane ze skał wapienia, dolomitu, piaskowca i szarogłazu. W składzie mineralnym kruszyw z wapieni i dolomitu nie stwierdzono obecności reaktywnych form kwarcu; w ziarnach kruszywa z szarogłazów i piaskowca występował kwarc mikro- i kryptokrystaliczny. Na podstawie wydłużenia próbek określono następujące kategorie reaktywności wybranych krajowych kruszyw ze skał osadowych: R0, R1 i R2. Zaobserwowano występowanie żelu krzemianu sodowo-potasowo-wapniowego o składzie charakterystycznym dla produktów reakcji alkalia-kruszywo, zgodnym z danymi literaturowymi. Uzyskano spójną ocenę reaktywności kruszyw.
EN
The paper presents the results of investigations into the reactivity of domestic aggregates produced from selected sedimentary rocks, carried out using the new testing methods, consistent with the RILEM and ASTM methods, implemented by GDDKiA (Polish General Directorate for National Roads and Motorways) documents. The range of the investigations covered coarse crushed aggregates produced from limestone, dolomite, sandstone and greywacke rocks, potentially suitable for making strong and durable concrete. No reactive forms of quartz were found in the mineralogical composition of the limestone aggregates and the dolomite aggregates. Micro- and cryptocrystalline quartz occurred in the particles of the greywacke aggregates and the sandstone aggregates. On the basis of the expansion of mortar and concrete specimens the aggregates produced from the sedimentary rocks were classified into the reactivity categories: R0, R1 and R2. A sodium-potassium-calcium silicate gel, whose composition (consistent with that reported in the literature) was characteristic of the alkali-silica reaction products, was found. The investigations resulted in a consistent assessment of the reactivity of the aggregates.
EN
An aryl-substituted aromatic acid ionic liquid (M-X) was synthesized through hexadecyl trimethyl ammonium bromide and sodium salicylate, and it was employed as a flotation collector for the separation of quartz from magnetite. Laboratory flotation studies of magnetite and quartz were conducted using the M-X and dodecylamine (DDA) as collector. The results showed that the M-X has a stronger collecting ability and selectivity for quartz without starch. The adsorption mechanism of M-X on quartz and magnetite surfaces was studied by Fourier transform infrared spectroscopy (FTIR), zeta potential and X-ray photoelectron spectroscopy (XPS) analysis. Results indicated that the adsorption of M-X on the quartz surface was more efficient than that on the magnetite surface. And the salicylate anion in M-X was found to have depression effect to magnetite.
EN
In this study, the surface properties and flotation behavior of quartz with NaOl as a collector in the presence of Ca2+ ions were investigated using density functional theory (DFT) calculations in conjunction with flotation tests, adsorption experiments, zeta potential measurements, and solution chemistry calculations. The results of the flotation and adsorption tests proved that Ca2+ promoted the flotation recovery and the adsorption density of sodium oleate on quartz at pH > 8. Zeta potential analyses and solution chemistry calculations demonstrated that Ca(OH)+ was the functional species which activated quartz. DFT calculations indicated that O atoms dominated the quartz (101) surface, and great electrostatic repulsion and space resistance existed between the surface and oleate anion.The spontaneous adsorption of H2O and OH- on the (101) surface made quartz surfaces hydrated and hydroxylated, and resulted in the hydrophilicity of quartz. The adsorption of Ca(OH)+ on quartz (101) surface was more favorable and able to repulse the water film, which decreased the electrostatic repulsion and space resistance, and further facilitated the adsorption of oleate anion. During the activating and collecting adsorption processes, electron transition occurred along the O1—Ca—O2 path, implying Ca(OH)+ acted as an intermediary and electron donator in the activation process.
EN
Three quartz samples extracted from different origins were collected for ESR evaluation to appreciate the optical bleaching characteristics of the E1’ centre in a long time scale. After exposure of about 400 hours to artificial sunlight, the E1’ centre were bleached to a steady increasing level, about 2.5 times of its natural level, and the increase level also exhibit a small variability among different sample origins. The constant increasing level provide a significantly evidence for the potential use of the natural signal intensities of quartz E1’ centre in tracing sediment provenance. The results show that the signal intensity of E1’ centre increased within beginning 84 h and decreased after 202 h as previous researches have partly predicted. After long time exposed to sunlight, there is no correlation between irradiated samples’ dose rate and its E1’ centre ESR signal intensity. Thus, no new convenient indication shed light on the possible use of the E1’ centre for ESR sediment dating.
EN
By the means of the technique of the Raman microspectrometry, the complex history of the Earth can be better understood. That is why the Raman spectra determinations are the object of interest in the present paper. The examples of such experiments are presented based on the analyses performed in last years in different scientific centers (Potsdam, Banská Bystrica, Budapest). The identification of inclusion content is shown and the conclusions are drawn for fluid inclusions in some quartz samples from two different localities in Poland – in the Carpathians and in the Fore-Sudetic Block. The implications of the Raman analyses are discussed. It results from the Raman analyses performed that not fluorescing, gas-filled bubbles of huge fluid inclusions from the Jabłonki and Rabe vicinity (the tectonic mélange zone in the Carpathians) have the complex composition of CH4, CO2 and N2 in different mutual proportions dependent on the sample and locality. In another place, despite the fluorescing background, only methane has been identified by Raman spectra. Similar gas compo¬sition was determined in the inclusions in the vein quartz in the Wądroże Wielkie area (the Fore-Sudetic Block).
PL
Złożona historia Ziemi może być lepiej zrozumiana przy pomocy microspektrometrii Ramana. Toteż oznaczenia widma ramanowskiego są przedmiotem zainteresowania bieżącej pracy. Zaprezentowano przykłady oznaczeń ramanowskich, wykonanych w ostatnich latach w różnych ośrodkach naukowych (Poczdam, Bańska Bystrzyca, Budapeszt). Przedstawiono identyfikację składu inkluzji i wyciągnięte wnioski dla inkluzji fluidalnych z próbek kwarcu z dwóch różnych lokalizacji w Polsce – Karpat i bloku przedsudeckiego. Przedyskutowano implikacje analiz widma Ramana. Jak wynika z przeprowadzonych badań, niewykazujące fluorescencji, wypełnione gazem pęcherze w olbrzymich inkluzjach w rejonie Jabłonek i Rabego (strefa melanżu tektonicznego w Karpatach) mają skład złożony z CH4, CO2 i N2 w różnych wzajemnych proporcjach w zależności od próbki i lokalizacji. W innym miejscu, niezależnie od zakłócającego obraz widma fluoryzującego tła, w spektrach Ramana można wyraźnie zidentyfikować metan. Zbliżony skład gazu określono w inkluzjach w kwarcu żyłowym w rejonie Wądroża Wielkiego (blok przedusedcki).
EN
Based on the assumption that fluorescence studies are an important tool in search and characterization of hydrocarbons, samples of rocks, minerals and the organic matter were collected in the Western Carpathian area spreading from the Mszana Górna region in the west to the Bieszczady Mts. in the east, and continuously, towards SE outside the Polish frontier, in Ukraine and Slovakia. Analytical procedures comprised preparation, microscopic observation of the material (organic matter and minerals) from the point of view of inclusions and fluorescence followed by detailed luminescence studies. Those steps have been followed by the microthermometric determinations. The application of the fluid inclusion methods, which are one of the newest analytical tools in the last two decades have led to the characteristics of fluids trapped in the inclusions in the area. The fluorescence studies showed some diversity of hydrocarbons both in compositions and in distribution. The analyses were performed in double-sided polished thin sections prepared based on cold techniques. Fluorescence of inclusions in two minerals, quartz and calcite, was checked in those specific thin sections either in glued wafers, or loose (single) crystals. The fluid inclusion studies were accompanied later on by solid organic matter inclusion studies. Those point to the presence of the following minerals: quartz, dolomite, calcite, clay minerals, gypsum with anhydrite admixture, traces of pyrite and siderite, feldspars. General distribution of fluorescing and not fluorescing inclusions suggests the presence of light hydrocarbons (methane) in the west and south of the area, being enriched in higher hydrocarbons (oil) towards the east.
PL
Badania fluorescencji podjęto w skałach, minerałach i bituminach w Karpatach Zachodnich w rejonie rozciągającym się od Mszany Górnej po Bieszczady i dalej – poza granicami Polski – na Ukrainie i Słowacji. Procedury analityczne obejmowały preparatykę, ocenę mikroskopową materiału (organika i minerały) z punktu widzenia występowania wrostków i fluorescencji inkluzji oraz zasadnicze badania świecenia. Po tych analizach wykonano oznaczenia mikrotermometryczne. Wszystkie badania przeprowadzono stosując nowe metody i nowoczesny sprzęt analityczny. W wyniku użycia metod badań inkluzji fluidalnych, będących jednym z najnowszych narzędzi analitycznych w ostatnim dwudziestoleciu, uzyskano charakterystykę fluidów zamkniętych w postaci inkluzji w minerałach. Badania fluorescencji wykazały zróżnicowanie wypełnień węglowodorowych. Analizy przeprowadzano w obustronnie polerowanych płytkach, przygotowanych na zimno. Badano dwa minerały – kwarc i kalcyt – zarówno w preparatach, jak i luźnych kryształach naturalnych (kwarc – diamenty marmaroskie). Badaniom inkluzji fluidalnych towarzyszyły analizy wrostków organicznych (np. badania czarnych agregatów występujących w odkrywkach w formie soczewek). W ich wyniku stwierdzono obecność następujących minerałów: kwarc, dolomit, kalcyt, minerały ilaste, mieszanina gipsu z anhydrytem, ślady pirytu i syderytu oraz skalenie. Ogólny rozkład fluorescencji wrostków w minerałach i inkluzji niewykazujących wzbudzenia sugeruje obecność lekkich węglowodorów (metan) w części zachodniej obszaru i na południu oraz wyraźne wzbogacanie w wyższe węglowodory (ropa naftowa) w kierunku wschodnim.
PL
Celem pracy było określenie stopnia deformacji kwarcu w wybranych surowcach skalnych stosowanych w produkcji kruszyw łamanych do betonu w Polsce. Kwarc o zdeformowanej strukturze, czyli kwarc w stanie naprężeń, zaliczany jest do składników mogących powodować szkodliwą reakcję alkalia–krzemionka (Alkali-Silica-Reaction – ASR) w betonie [3]. Ocena podatności na reakcję ASR odgrywa ważną rolę w wyborze kruszywa do betonu. W pracy do oceny stopnia deformacji struktury kwarcu wykorzystano analizę mikroskopową w świetle przechodzącym. Analizie poddano próbki surowców skalnych stosowanych do produkcji kruszyw łamanych do betonu z 5 zakładów eksploatacyjnych. W przypadku jednej próbki przeprowadzono obrazowanie transmisyjne (TEM). Obserwacje w mikroobszarach umożliwiły identyfikację anomalii optycznych oraz mikrostruktur kwarcu, charakterystycznych dla różnych stopni jego deformacji określonych według klasyfikacji zawartej w publikacji Tiechera i współautorów [5]. Wyniki badań wykazały, że w każdej z badanych próbek, poza próbką K1, identyfikowany był kwarc o różnych stopniach deformacji. Udział kwarcu wykazującego cechy odpowiadające poszczególnym stopniom deformacji struktury był różny w poszczególnych surowcach skalnych, co może mieć wpływ na kształtowanie ich podatności na reakcję alkalia–krzemionka.
EN
The aim of the research was to determine the deformation degree in quartz from particular rocks, which are being applied as crushed aggregates for concrete in Poland. Quartz with deformed structure, that is strained quartz, is determined as constituent which can cause nocuous alkali-silica reaction (ASR) in concrete [3]. Assessment of the susceptibility to alkali-silica reaction of quartz is crucial in the selection of the aggregates for concrete. In order to assess the deformation degree in quartz the optical microscopic analysis in transmitted light was conducted. The study involved the rock samples for crushed aggregate for concrete from 5 different quarries. In case of the one of the samples, the TEM analysis was applied. Examination under the microscope was applied to identify optical anomaly and microstructures related to particular deformation degrees of quartz determined according to the classification contained in the article by Tiecher et al. [4]. The results have indicated that in every sample, except for the K1 sample, the quartz crystals with different deformation degrees were identified. Quantity of the quartz grains featuring different degree of deformation varies in particular samples. That can affect their susceptibility to alkali-silica reaction.
EN
A novel and highly-efficient amino-acid-based collector, α-ethylenediamine lauric acid (α-EDA-LA), was studied to selectively beneficiate carbonate-containing refractory hematite ores. Single mineral and synthetic mixture flotation tests were carried out to investigate its floating performance. Zeta potential, fourier transform infrared spectroscopy (FTIR) and Density Functional Theory-based molecular simulation were used to identify the adsorption mechanism. The flotation results showed that quartz could be collected effectively at pH 11.0-12.0 in the reverse flotation. For siderite, the recovery peaked at 83.4% at pH 8.0, where siderite presented different floatability from magnetite and hematite. Exploiting such difference, the separation of siderite could be achieved. Zeta-potential measurements showed that α-EDA-LA adsorption on the surfaces of siderite and quartz decreased the corresponding zeta potentials at pH of 8.0-10.0 and 8.0-12.0, respectively. This means the adsorption overcome the electrostatic repulsion between α-EDA-LA and the mineral surfaces. The molecular simulation indicated that no chemisorption took place between α-EDA-LA and quartz. FTIR analysis suggested that α-EDA-LA was adsorbed on quartz via hydrogen bonding. The adsorption of α-EDA-LA on siderite surface was dominated by chemisorption, while further enhanced by hydrogen bonding. This study filled the gap in the research on siderite flotation reagents and its adsorption mechanism.
EN
The paper presents systematic studies on influence of state of dynamic adsorption layer (DAL) induced at the rising bubble interface on time-scale of the bubble attachment to quartz and mica surfaces immersed in pure n-cetyl-trimethylammonium bromide (CTAB) and mixed octanol/CTAB solutions of different concentrations. It was found that in the case of pure CTAB solutions, the influence of DAL on time of bubble attachment and the three-phase contact (TPC) formation (tTPC) strongly depends on solution concentration. Generally, two solution concentration regimes were distinguished – low and high - for which different degree of solid surfaces hydrophobization was observed. It was determined that for low concentration regime the solid surface is only slightly hydrophobized while for high regime, hydrophobicity of the solid surface is much higher. Consequently, wetting film rupture for low concentration regime is governed by electrostatic interactions while for high concentration regime significance of these interactions is much smaller. As a result, the DAL influenced the film rupture in these two regimes in a quite different manner. For mixed n-octanol/CTAB solutions it was found that CTAB molecules presence is necessary condition for wetting film destabilization. Moreover, thanks to the developed approach, allowing control of initial adsorption coverage over the bubble surface (independently on concentration), it was proved that constant adsorption degree of CTAB molecules at the bubble surface in the mixture, leads to identical times of the TPC formation.
EN
A new type collector α-Bromolauric acid (α-BLA) had been proved to be an efficient collector for quartz flotation. However, the effects of α-BLA on the flotation behavior of iron minerals and quartz-iron separation had not been investigated. In this study, collector α-BLA was synthesized in the laboratory. The flotation behavior of quartz, hematite and magnetite under α-BLA reverse flotation system were investigated and the separation mechanism of quartz-irons was studied by contact angle, zeta-potential and infrared spectroscopy. The results showed that the optimum flotation pH was 11.5 for quartz, 6.45 for hematite and 6.97 for magnetite. The best α-BLA concentrations was 75 mg/dm3 for quartz flotation, 125 mg/dm3 for hematite and magnetite flotation. The activator CaCl2 had little effect on the flotation of hematite and magnetite, but the minimum dosage 50 mg/dm3 of activator CaCl2 was necessary for quartz flotation. On the contrary, starch had no effect on the flotation of quartz, while the recoveries of magnetite and hematite tended to be 0% as starch concentration more than 80 mg/dm3. The separation mechanism of quartz from iron minerals under α-BLA reverse flotation system was that the starch could be selectively adsorbed on the surface of hematite and magnetite in the form of strong hydrogen bond adsorption. However, the same adsorption of starch did not occur on the surface of quartz, so the α-BLA can be successfully adsorbed on the surface of activated quartz to make the quartz strongly hydrophobic, and then to be floated out.
16
PL
W pracy przedstawiono wyniki badań dotyczących wykorzystania pomiarów dylatometrycznych jako metody oznaczania zawartości kwarcu w surowcach ilastych. Surowce te – jako podstawowy składnik stosowany w masach ceramicznych – decydują o wielu parametrach takich jak: właściwości reologiczne, temperatura wypalania, skurczliwość suszenia i wypalania, czy podatność na deformację piroplastyczną. Występowanie domieszek innych, nieilastych minerałów w podstawowym surowcu zazwyczaj jest niekorzystane, szczególnie dotyczy to nadmiernej zawartości kwarcu. Jego obecność jest na ogół szkodliwa ze względu na możliwe występowanie niekorzystnych przemian polimorficznych SiO2, którym towarzyszy zmiana objętości, co w konsekwencji może doprowadzić do zniszczenia wyrobu. W prezentowanej pracy określono metodą dylatometryczną zawartość kwarcu w wybranych surowcach ilastych takich jak: kaolin z kopalni „Turów II” w Turoszowie oraz czerwone iły triasowe z monokliny śląsko-krakowskiej ze złóż: Patoka, Albertów, Ligota Dolna i Woźniki. Przeprowadzona analiza dylatometryczna wykazała zróżnicowaną w nich zawartość kwarcu, która dla surowego kaolinu „Turów II” wynosi 40%, zaś dla iłów z monokliny śląsko-krakowskiej mieści się w przedziale (11-25)%.
EN
The results of research on the use of dilatometric measurements as a method for determining of quartz content in clayey raw materials are presented in this paper. These materials – as the main component used in the compositions of ceramic masses – determine many parameters such as: rheological properties, firing temperature, drying and firing shrinkage, as well as susceptibility to piroplastic deformation. The presence of admixtures of non-clay minerals in the basic raw material is usually unfavorable, especially in the case of excessive quartz content. Its presence is generally harmful due to the possible occurrence of unfavorable polymorphic SiO2 transformations, which are accompanied by a change in volume, which in consequence can lead to the destruction of the product. The quartz content of in selected clay raw materials were determined using the dilatometric method in the presented work. The studied samples were as follows: kaolin from the "Turów II" mine in Turoszów and Triassic red clays from the Silesian-Cracow monocline from the deposits: Patoka, Albertów, Ligota Dolna and Woźniki. The dilatometric analysis revealed different quartz content, which for "Turów II" kaolin is about 40%, and for red clays of Silesian-Cracow monocline is in the range of 11-25%.
EN
The Volochysk site belongs to important and unique loess sites in the Podolia Upland (W Ukraine) because it contains relatively well-developed loess deposits representing the last and penultimate glacial cycles. This loess-palaeosol sequence consists of pedocomplex S1 (MIS 5) developed on loess L2, and loess L1 (MIS 4-2) with the palaeosols of lower, interstadial rank. In this sequence, different periglacial structures were found, including the largest ones of ice-wedge cast type. Different quartz and polymineral fractions separated from the samples collected in the Volochysk site were dated using luminescence methods (SAR OSL, post-IR IRSL and TL) in three Polish luminescence laboratories in Gdańsk, Gliwice and Lublin. In total, 69 luminescence dating results were obtained for 18 samples. The methodological and research aims were to carry out mutual verification of the obtained dating results as well as to analyse and interpret the differences between them, and to determine the age of distinguished deposit layers and the period of cryogenic activities. The luminescence dates of the sediments, which were deposited during MIS 2, 3 and 4, corresponded fairly well to the ages attributed to these stages. They also indicate the age of periglacial phenomena. However, the TL dates were generally older than the OSL ones, especially those obtained for the sediments deposited during MIS 5 and 6. The results of the research of the Volochysk sequence were compared with those obtained in past years for the loess deposits of the Volhynian Upland (north of Podolia) during similar inter-laboratory analyses conducted to determine their age. The results of OSL datings of the older deposits (MIS 5 and MIS 6) are underestimated irrespective of the used method, and the type (quartz, polymineral) and size of grains. Numerous attempts were made to explain this phenomenon, which, however, give no answer. It was only found that this underestimation corresponded to the equivalent dose value of ~150 Gy.
18
EN
SAR-OSL dating studies of Romanian, Serbian and Chinese loess using fine and coarse quartz have previously resulted in a series of controversial issues. We extend here the investigations using fine (4–11 μm) and different coarse quartz (>63 μm) grains extracted from aeolianites from a site on Eivissa Island (southwestern Mediterranean). Aeolianites were chosen since they contain quartz from a different geological context and have significantly lower environmental dose rates. The dose response curves of the OSL signals for fine and coarse quartz are similar to those for loess and are also represented by the sum of two saturating exponential functions. For doses up to ~200 Gy, the dose response curves of fine and coarse grains from aeolianites can be superimposed and the ages obtained for the different grain sizes are in agreement up to ~250 ka, increasing our confidence in the accuracy of the ages obtained for samples with such doses, irrespective of the magnitude of the environmental dose rate. Particularly for the fine quartz fraction, a mismatch between the SAR dose response curve and the dose response curve obtained when doses are added to the natural is reported, indicating that the application of the SAR protocol in the high dose range is problematic. This dose dependent deviation is much less pronounced for coarse grains. Thus, it seems reasonable to infer that the dose response curves for the coarse grains, although saturating earlier can be regarded as more reliable for equivalent dose calculation than those for the fine grains.
EN
Due to the rapid development of geothermal technologies, the problem of efficient and proper evaluation of soil thermal conductivity becomes extremely important. Factors mostly affecting the soil conductivity are the conductivity of solid phase and the degree of saturation. The former one is mainly affected by the mineral composition, in particular, by the content of quartz whose conductivity is the highest one among all the minerals forming soil skeleton. Organic matter, because of its relatively low conductivity, influences the solid conductivity as well. The problem addressed in the paper is the influence of mentioned factors on temperature changes in the vicinity of thermally loaded structure embedded in the soil medium. Numerical simulations are carried out for different values of soil thermal conductivity resulting from various quartz contents and degrees of saturation. In addition, a weak coupled – heat and water transport – problem is considered.
EN
Quartz is, in most cases, the major gangue mineral found in the iron ores. Although it can be activated by calcium at strong alkaline pH, quartz nevertheless, reports to the concentrate with Fe when the iron ores contain siderite. It causes a poor concentrate grade and separation between quartz and iron minerals. The effect of siderite on reverse anionic flotation of quartz from hematite was studied in our previous investigations. In this work, the effect of siderite dissolution on the quartz recovery in the froth product and the effect of pH, ions and temperature on siderite dissolution were investigated. Microflotation, PHREEQC simulation, solution chemistry calculation and Fourier transform infrared spectroscopy (FTIR) measurements were conducted. It was observed that the dissolved species of siderite exhibited negative impact on quartz flotation. This influence became weak to some extent by either stripping the dissolved species or shortening dissolution time. Siderite was easily dissolved in the presence of calcium ion under strong alkaline conditions and its solubility increased with increasing the calcium ion concentrate and temperature. When the calcium ion was added as an activator of quartz under strong alkaline conditions (pH>9.96), calcium existed mainly in the CaCO3 precipitation form according to the solubility rule in the presence of siderite. This form could adsorb onto quartz surfaces and further the chemical reaction between starch and quartz was monitored by FTIR measurements. This study provides a further supplement for previous study. A potential strategy is suggested that finding a collector used at low temperature or flotation under neutral (or weak alkaline) medium is helpful to the reverse flotation of iron ores containing siderite.
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