Temat: mechanical activation

Skocz do pozycji: 1.

Tytuł:: Structure and Magnetic Properties of Bi5Ti3FeO15 Ceramics Prepared by Sintering, Mechanical Activation and Edamm Process. A Comparative Study
Autorzy:: Jartych, E.
Pikula, T.
Mazurek, M.
Franus, W.
Lisinska-Czekaj, A.
Czekaj, D.
Oleszak, D.
Surowiec, Z.
Aksenczuk, A.
Calka, A.
Tematy:: Aurivillius compounds
sintering
mechanical activation
magnetic properties; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352172.pdf Link otwiera się w nowym oknie
Opis:: Three different methods were used to obtain Bi₅Ti₃FeO₁₅ ceramics, i.e. solid-state sintering, mechanical activation (MA) with subsequent thermal treatment, and electrical discharge assisted mechanical milling (EDAMM). The structure and magnetic properties of producedBi₅Ti₃FeO₁₅ samples were characterized using X-ray diffraction and Mössbauer spectroscopy. The purest Bi₅Ti₃FeO₁₅ ceramics was obtained by standard solid-state sintering method. Mechanical milling methods are attractive because the Bi₅Ti₃FeO₁₅ compound may be formed at lower temperature or without subsequent thermal treatment. In the case of EDAMM process also the time of processing is significantly shorter in comparison with solid-state sintering method. As revealed by Mössbauer spectroscopy, at room temperature theBi₅Ti₃FeO₁₅ ceramics produced by various methods is in paramagnetic state.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Structure and hyperfine interactions of multiferroic Bim+1Ti3Fem-3O3m+3 ceramics prepared by mechanical activation
Autorzy:: Mazurek, M.
Jartych, E.
Oleszak, D.
Tematy:: Aurivillius compounds
hyperfine interactions
mechanical activation
Mössbauer spectroscopy; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/147810.pdf Link otwiera się w nowym oknie
Opis:: The structure and hyperfine interactions in the Bi5Ti3FeO15, Bi6Ti3Fe2O18 and Bi7Ti3Fe3O21 multiferroic ceramics were studied using X-ray diffraction and Mössbauer spectroscopy. Samples were prepared by mechanical activation process in a high-energy ball mill from a mixture of TiO2, Fe2O3 and Bi2O3 oxides as polycrystalline precursor materials. The mechanical milling process was completed by thermal processing. A pure single-phased material was obtained in the case of Bi7Ti3Fe3O21 compound. The proposed mechanical activation technology allows to produce the Aurivillius compounds at lower temperature, by about 50 K, as compared to the solid-state sintering method.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Control of Natural Zeolite Properties by Mechanical Activation in Stirred Media Mill
Autorzy:: Bohács, K.
Faitli, J.
Bokányi, L.
Mucsi, G.
Tematy:: zeolite
mechanical activation
zeta-potential
suspension rheology
FTIR; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353482.pdf Link otwiera się w nowym oknie
Opis:: Due to the special characteristics of zeolites, they can be applied in a very wide range of industries, i.e. agricultural, environmental or water treatment purposes. Generally, high added value zeolite products are manufactured by micro- or nanogrinding. However, these processes require high energy input and cause significant wearing of the mill parts. Therefore, the optimization of zeolite grinding, as well as the control of its properties are of a great importance. In the present paper a Hungarian natural zeolite was mechanically activated in stirred media mill for various residence times in distilled water, meanwhile the particle size distribution and the grinding energy were measured. Additionally, on-line tube rheometer was used to study the rheology of the suspension during the grinding process. The particle interaction and the suspension aggregation stability were detected by zeta-potential measurements. Structural changes due to the mechanical activation process were monitored by FTIR. It was found that the material structure of the zeolite, as well as the rheological behaviour of the zeolite suspension and its aggregation stability had been altered due to the mechanical activation in the stirred media mill. It can be concluded that the zeolite product properties can be modified by mechanical activation in order to produce a high added value tailored material.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Effect of mechanical activation on carbothermic reduction and nitridation of titanomagnetite concentrates
Autorzy:: Wen, Xiaojin
Yu, Wen
Zeng, Danliang
Zhu, Liang Liang
Chen, Jiangan
Tematy:: titanomagnetite concentrates
carbothermic reduction
mechanical activation
titanium nitride; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/1446680.pdf Link otwiera się w nowym oknie
Opis:: The carbothermic reduction and nitridation process of titanomagnetite concentrates with the help of mechanical activation were investigated by particle size analysis, thermodynamic calculation, thermogravimetric analysis, X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive spectroscopy analysis. The thermogravimetric and X-ray diffraction results indicated that either the reduction of iron oxide or the reduction and nitridation of M3O5 to TiN could be promoted significantly with the increase in activation time. The results obtained from scanning electron microscopy and energy-dispersive spectroscopy showed that, when samples were not activated, chunks of and thin M3O5 were derived from the reduction of ilmenite and titanomagnetite. They were severely sintered with impurities to form a dense structure. As a result, M3O5 was difficult to be converted to TiN, especially chunks of M3O5. However, when samples were activated, the sintering degrees of the impurity and M3O5 were mitigated, and the particle size of the iron as a medium for delivering C to M3O5 was decreased in the roasted product. This condition enhanced the diffusion of C to the surface of M3O5. Meanwhile, the bulk of ilmenite was broken in the activation process, which prevented the formation of chunks of M3O5. Thus, the conversion of M3O5 to TiN was promoted.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Structure and Mössbauer spectroscopy studies of mechanically activated (BiFeO3)1-x-(BaTiO3)x solid solutions
Autorzy:: Malesa, B.
Antolak-Dudka, A.
Oleszak, D.
Pikula, T.
Tematy:: ceramic solid solutions
hyperfine interactions
mechanical activation
Mössbauer spectroscopy; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148236.pdf Link otwiera się w nowym oknie
Opis:: (BiFeO3)1-x-(BaTiO3)x solid solutions with x = 0.1–0.4 and 0.7 were investigated. The ceramics were prepared by mechanical activation technology and subsequent heat treatment. As was proved by X-ray diffraction, increase of BaTiO3 concentration causes a change in the crystalline structure from the rhombohedral structure characteristic of BiFeO3 to a cubic one. 57Fe Mössbauer spectroscopy allowed observation of a gradual transformation from an ordered spin structure of Fe3+ ions to the paramagnetic state with an increase of x.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Potassium chloride recovery from mechanically activated microcline through the chlorination roasting and leaching route
Autorzy:: Alyosif, Bahaa
Uysal, Turan
Erdemoğlu, Murat
Tematy:: KCl
K-feldspar
chlorination roasting
mechanical activation
energy efficiency; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/24148588.pdf Link otwiera się w nowym oknie
Opis:: In this study, effects of mechanical activation in the chlorination roasting and water leaching route known as CaCl2 process and developed for the production of potassium chloride (KCl) from potassium feldspar ores were studied. A microcline containing K-feldspar ore with 10.89% K2O was first intensively dry milled by a planetary ball mill and mixed with calcium chloride (CaCl2) and then roasted at temperatures up to 1000 °C to obtain KCl that will be finally dissolved by the water leaching. Potassium recovery by water leaching increased rapidly up to 800 °C. At higher temperatures, the recovery decreased fast due to the evaporation of KCl. According to the K recovery values per unit energy consumed, the optimum roasting temperature was determined as 750 °C and the milling time was 15 min. It was concluded that intensive milling causes mechanical activation of the microcline to reduce the chlorination roasting temperature, which triggers a rise in the K recovery by the water leaching.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Waste Water Purification from Metal Ions by Ultra-Dispersed Natural Sorbents
Autorzy:: Yerbolov, Sezim
Daumova, Gulzhan
Tematy:: wastewater
metal ion
bentonite clay
shungite
mechanical activation
ultra-dispersed sorbent; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/2025790.pdf Link otwiera się w nowym oknie
Opis:: This work is devoted to mine wastewater purification from metal ions, such as copper, zinc, lead, cadmium, iron, and manganese. The rationale was provided for the possibility to purify the wastewater from metal ions with nonactivated and ultra-dispersed natural sorbents. The adsorption capacity of bentonite clay from Tagan deposit and shungite from Koksui deposit of the Republic of Kazakhstan was studied on the basis of its fraction composition. It was found that the most effective method of sorbents modification was mechanical activation. The comparative studies of metal ions adsorption efficiency were carried out with mechanically activated and ultra-dispersed bentonite clay and shungite. The experiment enabled to find out that ultra-dispersed bentonite clay is prospective for use in order to deeply purify multicomponent mine wastewater. The highest degree of metal ions extraction was achieved due to 30-minutes contact of wastewater.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Copper Leaching from Chalcopyrite: Mechanochemical Approach
Ługowanie miedz z chalkopirytu – aspekt mechaniczny i chemiczny
Autorzy:: Tesinsky, M.
Balaz, P.
Tematy:: mielenie
aktywacja mechaniczna
ługowanie
chalkopiryt
milling
mechanical activation
leaching
chalcopyrite; Pokaż więcej
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Powiązania:: https://bibliotekanauki.pl/articles/971182.pdf Link otwiera się w nowym oknie
Opis:: In the presented work, possibilities of intensification of copper leaching from chalcopyrite CuFeS2 induced by mechanical activation was studied. In this article, the influence of mechanical activation time on copper leaching efficiency is compared. This study also shows how mechanical activation time influences selectivity of copper and iron leaching. For mechanical activation, planetary mill Fritsch Pulverisette 6 at 400 rpm and room temperature was used. Grinding chamber (250 cm3 in volume) and 50 balls (10 mm in diameter) made of tungsten carbide were used. Specifically, the effect of mechanical activation time (4, 20, 30 minutes), the effect of temperature (40, 60, 80°C) on the copper recovery by leaching and the effect of the leaching atmosphere (air, argon) were examined. The results showed that the highest possible recovery of copper from chalcopyrite was obtained after 20 minutes of milling and leached in hydrochloric acid at 80°C, with air atmosphere without any oxidizing reagents.
W artykule przedstawiono możliwości intensyfikacji procesu ługowania miedzi z chalkopirytu CuFeS2 za pomocą aktywacji mechanicznej. Zbadano wpływ czasu aktywacji mechanicznej na efektywność ługowania miedzi. Wyniki badań pokazały również wpływ czasu na selektywność rozdziału miedzi i żelaza. Do aktywacji mechanicznej wykorzystani młyn planetarny Fritsch Pulverisette 6, aktywację prowadzono przy obrotach 400 rpm, w temperaturze pokojowej. Do badan wykorzystano komorę mielenia o objętości 250 cm3 i 50 kul o średnicy 10 mm wykonanych z węglika wolframu. Określono wpływ czasu aktywacji mechanicznej (4, 20, 30 minut), wpływ temperatury (40, 60, 80°C) na odzysk miedzi w procesie lugowania w atmosferze powietrza i argonu. Wyniki wskazują, że najwyższy możliwy odzysk miedzi z chalkopirytu uzyskano po 20 minutach mielenia i ługowaniu w kwasie solnym w temperaturze 80°C, w atmosferze powietrza, bez jakichkolwiek czynników utleniających.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Obtaining of Gold from Slovak Concentrate by Using an Innovative Method
Pozyskiwanie złota ze słowackiego koncentratu przy użyciu innowacyjnej metody
Autorzy:: Ficeriová, Jana
Dutková, Erika
Tematy:: gold
algae
molecular hydrogen
mechanical activation
złoto
algi
wodór molekularny
aktywacja mechaniczna; Pokaż więcej
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Powiązania:: https://bibliotekanauki.pl/articles/59114954.pdf Link otwiera się w nowym oknie
Opis:: The complicated processing of concentrates with low gold content and the long-time use of non-ecological methods was the motion for finding a more efficient process for this noble metal obtaining. From this point of view, this research was focused on obtaining of nano gold from the concentrate White Hill (Detva, Slovakia) using mechanical activation and mechano-biological activation in a molecular hydrogen solution. Gold in this complex concentrate occurs physically enclosed in the intercrystalline space of minerals and is also isomorphic and fills defects in their structure. The exclusion of gold from such complex mineral matrixes of the concentrate can be achieved using a mechano-biological process. This innovative method for obtaining of nano gold with the application of a molecular hydrogen solution is an advantageous alternative to the non-environmental reagents used. Compared to the most used worldwide toxic cyanide reagent, a solution with molecular hydrogen represents a low-cost and above all completely harmless reagent with very good kinetics. Mechanical processes use high-energy milling, which has an effect on the more intensive formation of surface and bulk defects in solid substances. The main advantage of mechanical processes is a smaller number of technological operations, a shorter time required to obtain the desired product at favorable environmental temperatures, and also the formation of nanostructures. The use of a biological process with the application of limnetic algae showed that algae with siliceous structures make it possible to obtain gold from the White Hill concentrate with nanoscale size. Limnetic algae (diatoms, golden algae) are part of aquatic ecosystems and create the largest matter of biomass from all plants on the Earth. The mechano-biological process is a method that enabled to obtain of gold nanoparticles with an average size of 100 nm from the Slovak gold-bearing concentrate from the White Hill deposit (BV-1). Mechanical activation of this concentrate and siliceous shells of the specified limnetic algae (Dinobryon, Surirella) in a molecular hydrogen solution caused changes in the physical-chemical properties of gold minerals as well as in the constituents of algae minerals. These structural changes had a decisive influence on the exclusion of gold nanoparticles into the molecular hydrogen solution under the defined reaction conditions. The gold nanoparticles were subsequently fixed in the cellular matrix of mechanically activated algae shells. The explanation of this phenomenon was the action of biomolecules, which the algae cells secreted in the course of reactions with metal ions present in the molecular hydrogen solution. Gold nanoparticles from the investigated concentrate were obtained by a new mechano-biological procedure already for four hours. In the case of mechanical activation of the concentrate, but without activation of the used algae, gold nanoparticles were excluded after sixteen hours. It follows from this knowledge that the application of an absolutely ecologically harmless aqueous solution enriched by molecular hydrogen and the use of limnetic algae confirmed the suitability of the innovative method for obtaining of nano gold from the concentrate. From the achieved research results significantly more effective kinetics is evident in the case of activated algae. Nanoparticles of gold obtained by the mentioned procedure can have important practical utilization, such as accelerating of the decomposition of dangerous substances or neutralizing pollutants in contaminated water, soil, and air. Simultaneously, obtaining of gold nanoparticles would also be beneficial for removing algae from the aquatic environment, where they are very dangerous for all living organisms.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Comparative analysis of process parameters of talc mechanical activation in centrifugal and attrition mill
Autorzy:: Andric, L.
Terzic, A.
Acimovic-Pavlovic, Z.
Pavlovic, L.
Petrov, M.
Tematy:: talc
mechanical activation
ultra fine grinding
ultra-centrifugal mill
attrition mill; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110391.pdf Link otwiera się w nowym oknie
Opis:: The efficiency of talc mechanical activation by means of two different mechano-activators - centrifugal and attrition mill is investigated in this study and the comparative analysis of the characteristics of obtained talc powders is presented. A new approach for obtaining high-grade talc concentrate with low Fe2O3 content is achieved through effect of mechanical activation of talc accompanied by hydrometallurgical process. The applied mechanical activation process conditions of ultra-centrifugal mill were defined by number of rotor revolutions, sieve mesh size, and current intensity. These operating parameters of the ultra-centrifugal mill were variable. Ultra fine grinding of talc in attrition mill (attritor) was carried out in various time intervals - from 5 to 15 min. The following technological parameters of the mechanical activation were monitored: time of mechanical activation, circumferential rotor speed, capacity of ultra-centrifugal mill, and specific energy consumption. The investigation was based on a kinetic model. The structure and behavior of activated samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and differential thermal analysis (DTA).
Dostawca treści:: Biblioteka Nauki

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