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Wyświetlanie 1-9 z 9
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:
Preliminary laboratory tests of a new fibre optic high temperature measurement device
Autorzy:
Lisiecka, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/173508.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
non-contact thermometer
high temperature measurements
fibre optic probe
Opis:
This article presents the laboratory verification of the author’s algorithm for temperature determination. The conducted tests confirm the ability to eliminate the measurement condition impact (emissivity of the radiation source, attenuation of the atmosphere) on non-contact thermometric measurement results. What is more, this method allows measurement for wavelength shorter than 1 µm to be carried out. The second stage of the work involved transmission tests of the fibre optic probe. The use of three quartz rods ensured that thermal radiation from each direction in a perpendicular plane to the probe head is collected and transmitted. The combination of the new temperature determination method and new constructed measurement instrument will allow the area of application of a non-contact thermometric device to be extended.
Źródło:
Optica Applicata; 2019, 49, 4; 669-677
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of a high temperature resistant and low friction fracturing fluid
Autorzy:
Xiao, B.
Zhang, S.
Zhang, J.
Hou, T.
Guo, T.
Powiązania:
https://bibliotekanauki.pl/articles/109339.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high temperature fracturing fluid
resistance to shearing
hydroxypropyl guar
low friction
delayed crosslinking
Opis:
The performance of a hydraulic fracturing fluid (HFF) system directly determines the efficiency of stimulation. Since the targeted formations of most oil fields in China are characterized by large depth (~5000 m), high temperature (160 to 180 °C) and tight lithology, newer and suitable HFFs have to be developed. Based on a newly synthetized organo-boron/-zirconium cross-linking agent (Gh-g), a composite temperature stabilizer (WJ-6) and other optimized additives via indoor evaluation, this study introduced a novel HFF, which is thermally stable at high temperature (HT) up to 180 °C and exerted low friction pressures. The performance of HFF was evaluated in the laboratory. The experimental results showed that the HFF system performed well at HTs. It maintained a viscosity of 100 mPa•s or more after 90 min of shearing (170 s−1) at 180 °C. Furthermore, the system exhibited delayed cross-linking. It took 120 s for the cross-linking reaction to complete; therefore, the tube friction was reduced to a large extent. Another characteristic feature of the formulated HFF system was the low friction pressures, where the drag reduction percentage was in the range from 35% to 70%. Moreover, only minor damage was caused by the fluid to the formation core samples. The average core permeability damage was 19.6%. All these qualities ensure that this fluid system is in full compliance with the requirements of the fracturing treatment.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 37-47
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient sulfidization of lead oxide at high temperature using pyrite as vulcanizing reagent
Autorzy:
Zheng, Y.-X.
Lv, J.-F.
Wang, H.
Wen, S.-M.
Huang, L.
Powiązania:
https://bibliotekanauki.pl/articles/110351.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
lead oxide
sulfidization roasting
pyrite
reaction mechanism
TG
Opis:
A sulfidization roasting-flotation process was usually viewed to be effective in treating the refractory oxide ore. In this paper, pyrite was proposed to be applied as a potential vulcanizing reagent to transform PbO or its surface to PbS based on feasibilities of technology and economy. The evolution process, phase and characteristics of crystal growth were investigated by TG, XRD and SEM-EDS, respectively, to interpret the interaction mechanism of lead oxide and pyrite at high temperature. It was found that the decomposition process of pyrite under argon atmosphere was a slow process of sulfur released from FeS2 to FexS, which made the process easier to be controlled. When PbO was introduced into the system, the initial solid-solid (PbO-FeS2) reaction and prevailing solid-gas (PbO-S2(g)) reaction occurred at about 500 °C and 700 °C, respectively. Combined with the SEM-EDS analyses results, the optimal temperature for the sulfidization of PbO should be in the range of 700-750 °C.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 270-277
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of surface properties of anthracite coals before and after high temperature heating process
Autorzy:
Xia, W.
Xie, G.
Powiązania:
https://bibliotekanauki.pl/articles/951846.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
heating
coal hydrophobicity
XPS
SEM
BET
contact angle
Opis:
Surface property plays a very important role on coal hydrophobicity which determines flotation behavior of fine coals. However, coal spontaneous combustion makes coal suffer both oxidation and high temperature heating processes. Coals from the outside of coal piles primarily suffer oxidation (or combustion process) while coals from the inside of coal piles primarily suffer high temperature heating process. It is necessary to investigate the changes in surface properties of coal before and after high temperature heating process. In this investigation, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), surface area (BET) and contact angle measurements were used to indicate the changes in surface properties of anthracite coal before and after high temperature heating process. Throughout this study, surface properties of coal changed significantly after high temperature heating process. Meanwhile, coal hydrophobicity can be also reduced after high temperature heating.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 205-212
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reduction of the impact of emissivity on high temperature measurements in non-contact thermometric devices
Autorzy:
Lisiecka, E.
Powiązania:
https://bibliotekanauki.pl/articles/174988.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
emissivity impact
high temperature measurements
non-contact thermometer
Opis:
Non-contact measurements of high temperature, accomplished with the use of infrared cameras and pyrometers, are utilized in many fields of science and industry. However, in order to obtain reliable measurement results from aforementioned devices, one should take account of the emissivity value of a thermal source the temperature of which is being measured. This is due to the necessity of calibration of non-contact thermometric devices in relation to emission characteristics of a blackbody, which is an ideal source with the maximum emissivity value. In order a non-contact temperature measurement was made possible without the necessity of taking into account the emissivity value, an original concept of the measurement method was developed, taking the advantage of thermal radiation laws – Planck’s law and Wien displacement law. The basic idea of the accepted method is the departure from amplitude recording (as in “conventional” pyrometry and thermovision) for linking of temperature recording with a maximum position in Planck’s curve. This article presents a novel approach that was used in the development of an original algorithm of temperature determination for performance of non-contact measurements of high temperature. The algorithm will enable to perform measurements without the necessity of introducing the emissivity value of a radiation source into a measurement instrument and will limit the impact of radiation absorption via the medium in which a measurement is being performed on the results of measurements. The applied methodology will allow conducting non-contact temperature measurements at a distance without the necessity of calibration the measuring device with regard to a blackbody.
Źródło:
Optica Applicata; 2017, 47, 3; 373-381
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fiber Bragg grating-based high temperature sensor and its low cost interrogation system with enhanced resolution
Autorzy:
Mamidi, V R
Kamineni, S
Ravinuthala, L N S P
Madhuvarasu, S S
Thumu, V R
Pachava, V R
Putha, K
Powiązania:
https://bibliotekanauki.pl/articles/949414.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber Bragg grating (FBG)
long period grating
fiber optic temperature sensor
optical intensity modulation
Opis:
A fiber Brag grating-based high temperature sensor together with a low cost, high speed and compact size interrogation system using a long period grating was designed, developed and tested. The designed sensor measures the temperature from room temperature to 550 °C. The sensor head was configured by encapsulating an fiber Brag grating (type-I) of Bragg resonance wavelength at 1552.88 nm in a capillary tube made of copper. Long period grating with peak transmission loss at 1550 nm was employed to convert the wavelength information from fiber Brag grating into an intensity modulated signal. Temperature related optical intensity information was again converted into its equivalent electrical signal by using a photodiode. The achieved resolution of the sensor was found to be 0.5 °C.
Źródło:
Optica Applicata; 2014, 44, 2; 299-308
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on preparation and properties of porous ceramsites sintered with high-ash coal slime
Autorzy:
Zhu, Dan
Min, Fanfei
Lv, Wenbao
Powiązania:
https://bibliotekanauki.pl/articles/27323640.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-ash coal slime
porous ceramsites
sintering temperature
ash content
Opis:
In order to realize the resource and harmless utilization of high-ash coal slime in coal preparation plants, porous ceramsites were prepared by the high-temperature sintering method with coal slime as raw material. The influences of sintering temperature, sintering time and ash content on the properties of porous ceramsites were studied by experiments, and the phase composition, micro-morphology and pore structure characteristics of ceramsites were analyzed by XRD, SEM and BET. The experimental results showed that with the increase of sintering temperature and sintering time, the amount of molten liquid in ceramsite green bodies increased, the densification degree of ceramsites increased gradually, the bulk density and the apparent density increased gradually, and the water absorption and the apparent porosity decreased gradually. However, with the increase of coal slime ash content, the quantity of pores within ceramsites increased first and then decreased. When the coal slime ash content was 55%, the bulk density of porous ceramsite sample was 0.549g/cm3, the water absorption rate was 64.63%, the specific surface area was 19.40m2/g, the crushing rate and wear rate were 0.14%, with rough surface, porous structure and excellent water absorption performance, which met the optimum performance requirements of porous ceramsites. At the same time, this research also provides a new idea and method for the reuse of high-ash coal slime resource, a by-product of coal washing and dressing.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 172665
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of thin films of high-k oxides grown by atomic layer deposition at low temperature for electronic applications
Autorzy:
Gieraltowska, S
Wachnicki, Ł
Witkowski, B S
Godlewski, M
Guziewicz, E
Powiązania:
https://bibliotekanauki.pl/articles/173591.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-k oxides
composite layers
atomic layer deposition
transparent electronics
zinc oxide
Opis:
Thin films of high-k oxides are presently used in semiconductor industry as gate dielectrics. In this work, we present the comparison of structural, morphological and electrical properties of binary and composite layers of high-k oxides that include hafnium dioxide (HfO2), aluminum oxide (Al2O3) and zirconium dioxide (ZrO2). We deposit thin films of high-k oxides using atomic layer deposition (ALD) and low growth temperature (60–240 °C). Optimal technological growth parameters were selected for the maximum smoothness, amorphous microstructure, low leakage current, high dielectric strength of dielectric thin films, required for gate applications. High quality of the layers is confirmed by their introduction to test electronic structures, such as thin film capacitors, transparent thin film capacitors and transparent thin film transistors. In the latter structure we use semiconductor layers of zinc oxide (ZnO) and insulating layers of high-k oxide grown by the ALD technique at low temperature (no more than 100 °C).
Źródło:
Optica Applicata; 2013, 43, 1; 17-25
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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