Ferenc Kristály

University of Miskolc · Institute of Mineralogy and Geology

This investigation presents the synthesis of equiatomic and non-equiatomic AlCo1−xFeNiTiMox (x = 0, 0.1, 0.25 and 1.0) high entropy alloys fabricated by mechanical alloying. Mo partially replaced Co. Classic thermodynamic calculations, such as mixing enthalpy (ΔHmix), configurational entropy (ΔSmix), the atomic size difference (δ), entropy to entha...

Polished stone axes were used in the Bronze Age Carpathian Basin, but their number decreased, specifically in burials, compared to the Neolithic and Copper Age. This is particularly appropriate after 1500 BCE when stone was hindered by increasing metalworking, and several types of bronze axes became widespread. In this context its highly important...

The 2,4-toluenediamine (TDA) is one of the most important chemicals in the polyurethane industry, produced by the catalytic hydrogenation of 2,4-dinitrotoluene (DNT). The development of novel catalysts that can be easily recovered from the reaction mixture is of paramount importance. In our work, a NiFe2O4/N-BCNT supported magnetic catalyst was pre...

In terms of rare earth potential, the Ditrău Alkaline Massif (Romania) is one of the most prospective formations in Europe. The REE mineralization occurs as mineralized ore veins and is most prominent in the northern (Jolotca) and eastern (Belcina) parts of the Massif. The ore veins of Jolotca area outcrop over a larger area than the Belcina ones,...

Bovine bones heated to 1100 °C under air atmosphere were studied using transmission electron microscopy. During heating, bone bioapatite was transformed into hydroxylapatite (HAp). Energy-dispersive spectroscopy did not indicate the presence of A-type CO3 substitution, it showed a near-ideal Ca/P ratio of 1.67 during heating. In the present study,...

Toluene diamine (TDA) is a major raw material in the polyurethane industry and thus, its production is highly important. TDA is obtained through the catalytic hydrogenation of 2,4-dinitrotoluene (2,4-DNT). In this study a special hydrogenation catalyst has been developed by decomposition cobalt ferrite nanoparticles onto a natural clay-oxide nanoco...

The multi-layer composite development primarily aims to develop and test the components of the next generation of hadron colliders (e.g., Large Hadron Collider - LHC) consisting of superconducting raw materials. Multilayer sheet is very similar to the commonly used NbTi wire products, a 2D version of the commercial wire. These composites consist of...

A late Neolithic flat adze, originated from Szerencs-Taktaföldvár locality, North Hungary, was studied from archaeometric aspect. The adze suffered an alkali metasomatism which was revealed by the strikingly high alkali content and a large amount of potassic feldspars. Ba-rich and Ba-free potassic feldspars, and tourmaline, as characteristic minera...

Catalysts with magnetic properties can be easily recovered from the reaction medium without loss by using a magnetic field, which highly improves their applicability. To design such systems, we have successfully combined the magnetic properties of nickel ferrite nanoparticles with the positive properties of carbon-based catalyst supports. Amine-fun...

Citation: Ilosvai, Á.M.; Forgách, L.; Kovács, N.; Heydari, F.; Szigeti, K.; Máthé, D.; Kristály, F.; Daróczi, L.; Kaleta, Z.; Viskolcz, B.; et al. Development of Polymer-Encapsulated, Amine-Functionalized Zinc Ferrite Nanoparticles as MRI Contrast Agents. Int. J. Mol. Sci. 2023, 24, 16203. https://doi.org/10.3390/ ijms242216203 Academic Editor: Liu...

The 'Y-adit' (Lillafüred, Bükk Mts.) was known for years as the only axinite (Ca-Al-borosilicate mineral group) occurrence from Hungary. Here the axinite is the component of hydrothermal quartz-albite-chlorite-calcite veins, in Triassic metabasalts. We report a new, recently discovered axinite occurrence from the Bükk Mts., at Létrás-tető Hill. Thi...

Mo-Cu alloys were fabricated by the mechanical alloying method and consolidated by cold and hot pressing at 950 • C with the addition of ceramic α-Al 2 O 3 (1-2.5 wt%). XRD was used to define the crystallinity and lattice defects of the mixed powder, milled powders, and hot-pressed samples after mechanical alloying experiments. The crystallite size...

For pathogens identification, the PCR test is a widely used method, which requires the isolation of nucleic acids from different samples. This extraction can be based on the principle of magnetic separation. In our work, amine-functionalized magnesium ferrite nanoparticles were synthesized for this application by the coprecipitation of ethanolamine...

Abstract: Easy preparation, good yield and easy recovery are the key challenges in the developmentof industrial catalysts. To meet all these three criteria, we have prepared intelligent, magnetizableNiFe2O4- and CoFe2O4-supported palladium catalysts that can be easily and completely recoveredfrom the reaction medium by magnetic separation. The fast...

Further mosaic-like data were recorded on the mineral occurrences of the Carpathian-Pannonian region in this fifth member of the series arranged by countries and localities. Each "mosaic" contains a concise mineral description, mainly based on XRPD, SEM-EDX and EPMA measurements and a concise description of the mineral paragenesis. Some minerals ar...

A rare earth (REE) and further rare element (Zr, Nb, Th, Ta) enrichment was found recently within the CriticEl project in 2016. Due to continuing studies, now we know about several enriched rock bodies from the SE and NE The enrichment was caused by metasomatic processes, during which fluids penetrated through the rock bodies, causing chemical and...

Catalytic activity of a palladium catalyst with a porous carbon support was prepared and tested for benzophenone hydrogenation. The selectivity and yields toward the two possible reaction products (benzhydrol and diphenylmethane) can be directed by the applied solvent. It was found that in isopropanol, the prepared support was selective towards dip...

The Baradla Cave has been an open and used natural cavity since ancient times. 20 pieces of polished stone tools of various raw materials were revealed from the cave site, which were analysed using non-destructive methods. Source areas were identified for those raw material types which have detailed mineralogical and rock chemistry data available....

During the development of plants, they acquire macro and micronutrients from mineral form through the very important contribution of soil bacteria and soil colloid. It is expected that by the application of mineral fertilizers to the soil the nutrient uptake will increase, but its not negligible the difference between the alteration of soil and oth...

The mineral nutrients uptaken by plants are partly deposited as inorganic crystalline materials, frequently as minerals occurring in nature. The chemical elements are derived mostly from the soil minerals, through complex biochemical pathways to uptake. In our experiments we have examined the biomineralization and effects of mineral fertilizers, su...

Different plants are accumulating different mineral materials according to their nutrient necessity. The deposited crystalline inorganic nutrients differ according to the plant species. In our experiments we investigated the effect of mineral fertilizers with different composition on the change the biomineralization composition. For the experiments...

Some plant species are capable of significant mineral matter uptake through biomineralization as proven by experiments. The process is different according to species, type and stage of development, none the less the use of mineral fertilizers is enhancing the uptake. Phytoextraction, as a way of element recovery, has decades long history, even if i...

The subject of our research was the detection of the effect of mineral fertilization with Bodrogkeresztúr rhyolite tuff on lavender plantation (Szentendre). Although there are qualitative and quantitative differences in the components of the extracted oil, at least as are important the presence, type and amount of inorganic minerals in the organic...

Using our small-scale laboratory experiments, we investigated the effect of volcanic rocks on the water retaining propertzies of calcareous alluvial soils. The high porosity of the Bodrogkeresztúr rhyolite tuff ("potassium tuff") and in some variants, the presence of zeolites in the mining product is expected to have a positive effect on water upta...

This study demonstrates the possibility of high field strength element (HFSE) enrichment in a geological setting which differs from the known models, as no contacted alkaline magmatic rock body, or other potential source is known. Metasomatised rock bodies were discovered recently in fault blocks of two major fault zones of the Bükk Mts. The existe...

The present study is a review of publications regarding special aspects of the mineralogy of the Kaba meteorite, clay minerals, hydrous phases, and organic matter. In Section 1, the history of fall and finding of the meteorite and the first classical mineralogical description in the Year 1961 are mentioned. The most frequent alteration product of p...

2,4-diaminotoluene (TDA) is one of the most important polyurethane precursors produced in large quantities by the hydrogenation of 2,4-dinitrotoluene using catalysts. Any improvement during the catalysis reaction is therefore of significant importance. Separation of the catalysts by filtration is cumbersome and causes catalyst loss. To solve this p...

The suitability of pumice, an altered volcanic rock, for the synthesis of geopolymer cement has been investigated. The reactivity of pumice was improved by mechanical activation (MA) in a stirred media mill for various rotor speeds (3 and 5 m/s) and residence times (ranging from 1 to 10 min), respectively. MA resulted into increase in specific surf...

A Baradla-barlang egy ősidők óta nyitott barlang, melyet a régi idők embere is ismert, időszakos lakóhelyként, mene-dékként, esetleges rituálé helyszíneként használt hosszú idő-kön át. Korábbi kutatások során a Herman Ottó Múzeum régé-szeti gyűjteményéből megismerésre került három kőeszköz a Baradla-barlangból. További vizsgálati célul tűztük ki az...

Granulated carbon nanotube-supported palladium and platinum-containing catalysts were developed. By using these, remarkable catalytic activity was achieved in chlorate ion hydrogenation. Nitrogen-doped bamboo-like carbon nanotubes (N-BCNTs) loaded gel beads were prepared by using Ca2+, Ni2+ or Fe3+ ions as precursors for cross-linking of sodium alg...

The Bükk Mts. in NE Hungary exposes Paleozoic and Mesozoic successions containing volcanic formations both in the oceanic crust-derived Szarvaskő Unit and in the continental crust-derived Paraautochthonous Unit. The rocks of this latter unit were subject of multiple metamorphic, also metasomatic alterations and deformation events obscuring and over...

In this paper, the preparation of calcium oxide (CaO) nanoparticles (NPs) is reported by a precipitation method, using CaCl 2 and NaOH as starting raw materials. The produced NPs were characterized for chemical composition, phase composition, particle size distribution, morphological features, specific surface area, and crystallite sizes. It is sho...

Aniline is one of the most important chemical in the polyurethane industry and it is produced by the catalytic hydrogenation of nitrobenzene. The development of novel, multifunctional catalysts, which are easily recoverable from the reaction mixture is therefore of paramount importance. Transition metal-containing ferrites decorated with palladium...

Aniline (AN) is one of the most important compounds in the chemical industry and is prepared by the catalytic hydrogenation of nitrobenzene (NB). The development of novel, multi-functional catalysts which are easily recoverable from the reaction mixture is, therefore, of paramount importance. Compared to conventional filtration, magnetic separation...

The geologically young age of Ciomadul is not only highlighted by the presence of intact volcanic landforms (such as crater lakes), but also through the occurrence of sulphate minerals, gas emissions typically as mofettes, and mineral-rich water springs that occur around the volcano. This volcanic-related activity has played an important role to th...

Nowadays, the use of hybrid structures and multi-component materials is gaining ground in the fields of environmental protection, water treatment and removal of organic pollutants. This study describes promising, cheap and photoactive self-supported hybrid membranes as a possible solution for wastewater treatment applications. In the course of this...

The combination of the sonochemical activation of Ni(NO3)2 and Co(NO3)2 in the presence of Fe(NO3)3 and polyethylene glycol and consecutive heat treatment of the formed metal hydroxides offers a cheap and efficient method for the preparation of nickel ferrite and cobalt ferrite magnetic nanoparticles, which can be successfully applied in the select...

Nanotechnology plays a vital role in all the scientific fields including environmental research due to their surface: volume ratio compared to bulk materials. Recent studies prove their effectiveness as pollutant removal and remediation practices. Zinc oxide (ZnO) nanoparticles a multifunctional material with distinct properties and their doped cou...

Titanium monoboride (TiB) whisker-reinforced titanium (Ti) matrix composites were produced by powder metallurgy, through vacuum sintering. TiB is formed by thermal decomposition of TiB 2 precursor. In addition, a new hybrid composite was developed by admixing nanograined and nanocrystalline (more important) Ti to enhance the transformation mechanis...

In this study, Zr-pillared montmorillonite clays (Zr-PILCs) were synthesized using two different precursor materials: raw montmorillonite (CM) and sodium ion-saturated montmorillonite (Na-CM) at different Zr/clay ratios (2.5, 5 and 10 mmol/g). To study the effect of Zr concentration and clay pre-treatment with NaCl on pillaring, the modified clay s...

Maghemite particles were synthesized by using a combined combustion method and sonochemical step. Maghemite was used as carrier to prepare supported Pt and Pd catalysts after deposition via a sonochemical step. The catalysts were immediately ready to be used (metals were catalytically active) for the 2,4-dinitrotoluene hydrogenation to produce 2,4-...

Cellulose grains were carbonized and applied as catalyst supports for nickel- and magnetite-promoted bimetallic palladium- and platinum-containing catalysts. The bimetallic spherical aggregates of Pd and Pt particles were created to enhance the synergistic effect among the precious metals during catalytic processes. As a first step, the cellulose b...

The kinetics of transformation of 5 w% TiB2 nano-particles (50 nm diameter) dispersed and pressed (1.5 GPa) in the of Ti matrix (150 μm diameter) into TiB nano-whiskers was studied as a function of temperature (800 - 900 - 1000°C) and time (5 - 720 min) in 25 experiments in total, by vacuum sintering. The classical one-step Avrami kinetics does not...

The structure of the Bükk Mts. was formed as a result of a polyphase deformation history. Successions ranging from the Carboniferous to the Jurassic, mostly of Dinaric analogy, are uplifted and exposed here surrounded with the Cenozoic sediments and volcanics of the Pannonian Basin. The existence of a previously unknown HFSE (Nb, Ta, Th, Zr, Y and...

A remarkable number of scientific papers are available in the literature about the bulk amorphous alloys and metallic glasses. Today, DSC is an essential tool for amorphous alloys research and development, and of course for quality assurance. In many cases, users seek to examine the determination of only one or two properties, although much more in...

The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen, closely associated with the main gold-bearing sulfide arsenic ores of the Bakyrchik gold deposit (Kazakhstan), related to post-collisional magmatic-hydrothermal origin. Gold mineralization of the deposit occurs mainly in the form of an “invisible” typ...

Environmental geological survey of a chemical works situated in NE Hungary has been performed for decades. Up till now, several hundreds of drillings of different depths as well as engineering geological soundings have been carried out in the area. Vivianite has been found in a discrete part of a drilling in a gray, silty bed at the depth 6.8–8.5 m...

Carbon black supported palladium-platinum catalysts were prepared with and without nickel(II) oxide or iron(III) oxide promoter materials. By applying ultrasonic cavitation highly efficient carbon black supported catalysts were created. The designed catalyst preparation is a one-step procedure, as post-treatments (e.g. calcination, hydrogen activat...

The volume fraction of austenite (γ), ε martensite and α′ martensite is of key importance in the research of TWIP/TRIP steels. When mechanical loading is involved, the crystallographic texture also develops, which complicates X-ray diffraction-based phase ratio determination. The problem is more pronounced when only a couple, or only one Bragg-refl...

In the present article a 45Mo-45Cu-10Al2O3 (wt%) nano-composite was produced by mechanical alloying, shaped by cold pressing then by hot pressing at 950 °C. Our aim was to investigate the effect of different ball to powder ratio (BPR) on the particle size and shape, as well as on the material composition. Investigations were done with XRD, SEM and...

Cobalt, copper, and nickel ferrite spinel nanoparticles have been synthesized by using a combination of sonochemical treatment and combustion. The magnetic nanoparticles have been used as supports to prepare ~4 wt% palladium catalysts. The ferrites were dispersed in an ethanolic solution of Pd(II) nitrate by ultrasonication. The palladium ions were...

Mineral carbonation is a potentially attractive sequestration technology for the permanent safe disposal and immobilization of CO 2 . In this technology, CO 2 is chemically reacted with calcium, sodium, and magnesium containing materials to form thermodynamically stable and environmentally harmless minerals, usually carbonates. In our research, mec...

Cu/AlN–Al2O3 nano-multilayer (NML) was deposited by magnetron sputtering method on 42CrMo4 steel samples, starting with a 15 nm AlN–Al2O3 layer and followed by 200 alternating layers of 5 nm thick Cu and 5 nm thick AlN–Al2O3 layers. The microstructure and thermal behaviour of the as-deposited and heat-treated multilayer was studied. Starting from a...

The reduction of undesirable chlorate (ClO3-) is important from both an environmental and an industrial point of view. In our work, cellulose-based catalysts have been designed for chlorate reduction by using palladium, platinum, and iron oxide. The produced catalysts were characterized by SEM, TEM, XRD, FTIR, and ICP. Even though low precious meta...

Carbon foams have gained significant attention due to their tuneable properties that enable a wide range of applications including catalysis, energy storage and wastewater treatment. Novel synthesis pathways enable novel applications via yielding complex, hierarchical material structure. In this work, activated carbon foams (ACFs) were produced fro...

Glassy carbon foam (GCF) catalyst supports were synthesized from waste polyurethane elastomers by impregnating them in sucrose solution followed by pyrolysis and activation (AC) using N2 and CO2 gas. The palladium nanoparticles were formed from Pd(NO3)2. The formed palladium nanoparticles are highly dispersive because the mean diameters are 8.0 ± 4...

This is the fourth paper presenting new mosaic-like mineralogical data from the Carpathian-Pannonian region. Data are arranged by countries and localities. Every section gives a description (including XRPD, EMPA and SEM-EDX results) of the minerals and a concise description of their parageneses. Every discussed mineral is first described from the g...

The Jenkyns Event or Toarcian Oceanic Anoxic Event (T-OAE) was an episode of severe environmental perturbations reflected in carbon isotope and other geochemical anomalies. Although well studied in the epicontinental basins in NW Europe, its effects are less understood in open marine environments. Here we present new geochemical (carbon isotope, Ca...

Graphite, one of the polymorphic forms of carbon, has become a versatile industrial material of nowadays due to its particular attributes. It is used mainly in the automobile industry, metal extractive industry and in the high-tech industry. Moreover, it is also included in the list of critical raw materials for the EU. Our aim was to prove the pre...