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Wyszukujesz frazę "carbothermal reduction" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Microstructures and Microwave-Absorbing Properties of ZnO Smoke from Zinc Leach Residue Treated by Carbothermal Reduction
Autorzy:
Ma, Zhiwei
Wang, Sheng
Du, Xueyan
Zhang, Ji
Zhao, Ruifeng
Zhang, Shengquan
Powiązania:
https://bibliotekanauki.pl/articles/2049146.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zinc leach residue
carbothermal reduction
ZnO smoke
microwave-absorbing properties
Opis:
Much zinc residue is produced during the traditional processes involved in zinc hydrometallurgy in the leaching stage: its composition is complex and valuable metals are difficult to recover therefrom. If not handled properly, it can lead to a waste of resources and environmental pollution. To solve this problem, zinc leach residue specimens were treated using the carbothermal reduction method (CTR) that is easy to operate and has a high energy utilisation rate. The methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) were used for analytical characterisation. Based on this, this research investigated a structure-function relationship between microstructures and microwave-absorbing properties of ZnO smoke from CTR-treated zinc leach residue. The results demonstrate that microstructures and macro-properties of ZnO smoke obtained at different temperatures differ greatly. Under conditions including a calcination temperature of 1250°C, holding time of 60 min, and addition of 50% and 10% of powdered coal and CaO separately, the ZnO content in the obtained smoke is 99.14%, with regular micron-sized ZnO particles therein. For these particles, the minimum reflection loss (RLmin) reached –25.56 dB at a frequency of 15.84 GHz with a matching thickness of 5 mm. Moreover, frequency bandwidth corresponding to RL < –10 dB can reach 2.0 GHz. ZnO smoke obtained using this method is found to have excellent microwave-absorbing performance, which provides a new idea for high-value applications of zinc-rich residue.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1163--1170
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-temperature carbothermal dephosphorization of Malaysian monazite
Autorzy:
Udayakumar, Sanjith
Sheikh Abdul Hamid, Sheikh Abdul Rezan
Baharun, Norlia
Pownceby, Mark
Powiązania:
https://bibliotekanauki.pl/articles/2146886.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
malaysian monazite concentrate
dephosphorization
carbothermal reduction
rare earth elements
graphite
Opis:
High-temperature carbothermal reduction experiments with graphite powder were conducted to assess the dephosphorization behavior of Malaysian monazite concentrate. Thermodynamic analysis of the possible dephosphorization reactions was conducted to evaluate the feasibility of the carbothermal reduction of the monazite phases. The effects of temperature, particle size, and monazite to carbon ratio were then investigated under different conditions. The carbothermal reduction experiments were conducted based on the Taguchi design method, and up to 97% of phosphorous removal was achieved under optimized conditions. The optimal conditions for dephosphorization were determined as; a reduction temperature of 1350 °C, a particle size of -75 μm, and monazite to carbon molar ratio of 0.3. Microstructural and phase characterization of the dephosphorized products revealed that CeO2, Nd2O3, La2O3, and Pr2O3 oxide phases were prominent, and no residual peaks of monazite remained in the reduced products. The information gained from the study can aid in the design of a suitable post-dephosphorization hydrometallurgical treatment for exploiting Malaysian monazite as a local source of REEs.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 6; 140--155
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminum Nitride Formation From Aluminum Oxide/Phenol Resin Solid-Gel Mixture By Carbothermal Reduction Nitridation Method
Wytwarzanie azotku aluminium z żelowej mieszaniny tlenku aluminium z żywicą fenolową metodą azotowania podczas carbotermicznej redukcji
Autorzy:
Mylinh, D. T.
Yoon, D. H.
Kim, C.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/356779.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum nitride
powder
carbothermal reduction
nitridation
solid-gel mixture
azotek aluminium
proszek
redukcja karbotermiczna
azotowanie
żelowa mieszanina
Opis:
Hexagonal and cubic crystalline aluminum nitride (AlN) particles were successfully synthesized using phenol resin and alpha aluminum oxide (α-Al2O3) as precursors through new solid-gel mixture and carbothermal reduction nitridaton (CRN) process with molar ratio of C/Al2O3 = 3. The effect of reaction temperature on the decomposition of phenol resin and synthesis of hexagonal and cubic AlN were investigated and the reaction mechanism was also discussed. The results showed that α-Al2O3 powder in homogeneous solid-gel precursor was easily nitrided to yield AlN powder during the carbothermal reduction nitridation process. The reaction temperature needed for a complete conversion for the precursor was about 1700°C, which much lower than that when using α-Al2O3 and carbon black as starting materials. To our knowledge, phenol resin is the first time to be used for synthesizing AlN powder via carbothermal reduction and nitridation method, which would be an efficient, economical, cheap assistant reagent for large scale synthesis of AlN powder.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1551-1555
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Formation, Properties and Use of Dispersed Iron-Graphite Metallurgical Waste
Autorzy:
Dan, Leonid
Maslov, Vladimir
Trofimova, Larysa
Cios, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/2172384.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
dispersed iron-graphite waste
graphite
iron oxides
specific saturation magnetization
magnetizing annealing
carbothermal self-reduction
magnetic graphite
Opis:
Dispersed wastes containing graphite, iron, and its oxides, getting into the air and accumulating in landfills, cause serious harm to human health and the environment. Moreover, even if the issue of the localization of these wastes has been solved successfully, their disposal has not yet been fully organized. In the present study, a systematic analysis of the dispersed iron-graphite waste (IGW) conditions for the formation at metallurgical enterprises, their structure, and their properties were carried out. In this case, special attention is focused on the electrophysical properties: specific saturation magnetization and volume resistivity. The presence of magnetic properties in IGW, combined with low electrical resistivity, makes IGW a promising and inexpensive raw material for obtaining cheap composite materials with radio shielding and radio absorbing properties in the microwave range. As a result of the research, effective ways of improving the magnetic properties of IGW by high-temperature treatment were obtained. The practical result of the research was the development and implementation of a technological scheme of dispersed IGW complex processing, which makes it possible to solve a twofold task – to exclude the ingress of iron-graphite wastes into the environment and to obtain a cheap material for protection against microwave radiation.
Źródło:
Journal of Casting & Materials Engineering; 2022, 6, 4; 81--92
2543-9901
Pojawia się w:
Journal of Casting & Materials Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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