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Wyszukujesz frazę "Mechano-chemical" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Solid-State Mechanochemical Synthesis of Kaolinite-Urea Complexes for Application as Slow Release Fertilizer
Autorzy:
AlShamaileh, Ehab M.
Al-Rawajfeh, Aiman E.
Alrbaihat, Mohammad R.
Powiązania:
https://bibliotekanauki.pl/articles/123521.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
mechano-chemical
ball milling
slow release
kaolinite
urea
Opis:
This study investigated a mechanochemical (MC) process for synthesizing a slow-release urea fertilizer by cogrinding the starting materials of (NH2)2CO and amorphous kaolinite in a planetary ball mill. The tests with kaolinite contents ranging from 25 to 75 wt. %, milling time ranging from 1 (h) to 3 (h) and mill rotational speeds from 200 to 700 rpm were performed to evaluate the incorporation of (NH2)2CO and release of nitrogen into the solution. The analyses conducted using XRD, TGA, FT-IR and KNDU (Kjeldahl Nitrogen Determination Unit) indicated that the MC process was successfully applied to incorporate (NH2)2CO into the amorphous kaolinite structure. The release of nitrogen from the system (kaolinite-(NH2)2CO) when dispersed in water for 24 h reached up to 20% at 25% wt of kaolinite. Moreover, under the milling speed conditions for the system (kaolinite–(NH2)2CO), release of nitrogen reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolinite to act as a carrier of nitrogen nutrients to be released slowly for use as fertilizer.
Źródło:
Journal of Ecological Engineering; 2019, 20, 9; 267-276
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and structural characterization of niobium-doped hydroxyapatite ceramics
Autorzy:
Korzeniewski, Wojciech
Witkowska, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/284989.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
structure
nanoceramics
sol-gel method
hydroxyapatite
niobium
mechano-chemical synthesis
Opis:
Hydroxyapatite (HAp) ceramic materials are consi-dered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important role in improving its structural and physico--chemical properties. HAp doped with niobium ions has not been widely investigated so far. However, the results of studies available in the literature show that the synthesized CaO-P2O5-Nb2O5 compounds still show good biocompatibility, very low cytotoxicity and, additionally, they stimulate osteoblast proliferation. Therefore, this study is dedicated to the niobium--doped HAp ceramics obtained by two methods: mechano-chemical synthesis and sol-gel method. Bioceramics chemical composition, morphology, and structure were characterized by means of scanning electron microscopy imaging, BET method, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results indicate that nanoceramics of non-stoichiometric HAp with a clear Ca deficiency on the nanograin surface were obtained. Moreover, it has been observed that the presence of Nb dopants and the synthesis method directly affect unit cell parameters, crystallinity degree, crystallites size, porosity and distribution of niobium in the grain structure. Mechano-chemical synthesis has allowed effective niobium incorporation into the HAp structure, leading to the quite homogeneous Nb distribution in the grain volume. Whereas, Nb-doping by sol-gel method has led to dopants location mainly on the grain surface.
Źródło:
Engineering of Biomaterials; 2019, 22, 150; 10-15
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes of surface properties of calcite particles with calcium stearate using conventional experimental design and properties of coated calcite
Autorzy:
Ucurum, M.
Bayram, O.
Toraman, O. Y,
Kılıc, H.
Yalcın, S.
Powiązania:
https://bibliotekanauki.pl/articles/109347.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
calcite
surface modification
mechano-chemical
calcium stearate
properties of modified calcite
Opis:
Calcite is utilized as a filler mineral in the industries such as plastics, rubber, and paint, to gain products with a variety of features. In order to use a calcite ore as a filler, some specific physical and physico-chemical properties are required such as ultra-fine sizes and conversion of hydrophilic to hydrophobic structure. In the present study, for these purposes, surfaces of the ultra-fine calcite powder (d50=2.94 μm) were coated by a mechano-chemical process with calcium stearate [Ca(C17H35COO)2] in a stirred ball mill. The influence of operating parameters such as calcite filling-ratio, ball-filling ratio, operation speed, grinding time and chemical dosage on the active ratio (%) was systematically examined. Then, the properties of modified calcite product were measured and evaluated by contact angle, TGA, DTA, FTIR, and SEM. The results showed that the mechano-chemical technology is very effective for modifying the surface of micronized calcite products using calcium stearate chemical.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 688-700
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of polymers on the grinding and rheology of ultrafine Egyptian calcium carbonate suspension
Autorzy:
Mourad, Sabreen H
Khalil, Mostafa M. H.
Abdel-Khalek, N. A.
Abdel-Khalek, M. A.
Selim, K. A.
Hassan, El-Sayed R. E.
Powiązania:
https://bibliotekanauki.pl/articles/2175428.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fillers
calcium carbonate
ultra-fine grinding
surface modifications
Mechano-chemical
activation
polymers
Opis:
The investigation of surface modification of Egyptian calcium carbonate via polymers was achieved with simultaneous ultra-fine grinding. Attrition mill and planetary mill were used for wet and dry grinding, respectively. The parameters affecting the grinding were studied such as ball number, speed and grinding time. The rheological characteristics of the aqueous calcium carbonate suspensions were studied in the presence of different types of polymers. The results indicated that the mechanical force could clearly affect the modification characteristics of calcium carbonate due to its mechanochemical effects. The viscosity of calcium carbonate suspension depends on the volume percentage or weight percentage. The dispersing agent increases the solid concentration for a given particle fineness.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 152163
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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