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Wyświetlanie 1-4 z 4
Tytuł:
Preconcentration of a low-grade betafite ore by dense medium cyclone
Autorzy:
Lv, Zihu
Wei, Min
Zhao, Dengkui
Wu, Dongyin
Liu, Changmiao
Cheng, Hongwei
Powiązania:
https://bibliotekanauki.pl/articles/2146943.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
preconcentration
betafite
dense medium cyclone
uranium
niobium
Opis:
In order to find an economical and feasible short process for betafite preconcentrating and to provide a reference for the development of similar low-grade uranium deposits, preconcentration of the betafite ore was investigated based on mineralogical characterization study, float-sink tests, and dense medium cyclone (DMC) separation experiments. The float-sink test results revealed that the gravity separation of the betafite ore was feasible, and the expected particle size range was chosen to be 3~0.3 mm. The effect of important parameters of the DMC experiment such as particle size, grade of the feed, separation density, and inlet pressure on the separation performance of betafite ore was studied. Under the optimal experimental conditions, the expanded experiments were performed and the heavy minerals contained 4557 ppm U and 5200 ppm Nb2O5 with a recovery of 88.86% and 79.73%, respectively, were obtained. Besides, the enrichment ratio (E) values of U and Nb2O5 were 14.24 and 12.78 severally, and the tailings discarding ratio (R) value was 93.76%. The results demonstrate that the preconcentration of low-grade betafite by DMC can remove a large number of tailings and obtain a high-grade uranium concentrate.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 1; 1--14
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical and chemical processes of Abu Rusheid cataclastic rocks for recovering niobium, zirconium and uranium compounds
Autorzy:
Abdellah, Walid Mahmoud
Khalafalla, Mahmoud Sayed
Abu Khoziem, Hanaa Abdelaal
El Hussain, Omneya Mouhamed
Powiązania:
https://bibliotekanauki.pl/articles/2146869.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
physical processes
chemical processes
cataclastic rocks
separation
niobium
zirconium
uraniom
Opis:
Cataclastic rocks of Abu Rushied area (South Eastern Desert, Egypt) characterized by the presence of niobium, tantalum, zirconium minerals as well as uranium-thorium minerals. Physical upgrading process was applied using gravity and magnetic separation techniques to concentrate these economic minerals mainly to obtain the magnetic niobium concentrate at 0.2- 0.5 ampere, beside the non-magnetic Zr and U at 1.5 ampere. The chemical processing upon niobium concentrate was performed using NH4F roasting process at 250ºC followed by selective precipitation of Nb as Nb-sulfide. An alkaline fusion using NaOH was applied upon zirconium concentrate at the optimum conditions of: zircon concentrate/ NaOH mass ratio 1/2, fusion temperature of 650ºC and 2.5h fusion time followed by selective precipitation of Zr as Zr- tartrate. Finally, two flowsheets were drawn summarizing the whole recovery processes.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 5; 137--152
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activation mechanism of tantalum niobium flotation by lead ions in a combined collector flotation system
Autorzy:
He, Mingfei
Li, Shuangke
Cao, Miao
Gao, Yude
Bu, Hao
Meng, Qingbo
Powiązania:
https://bibliotekanauki.pl/articles/1448361.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tantalum niobium ore
Pb2+ ions activation
ammonium dibutyl dithiophosphate
coadsorption
Opis:
The effect of lead ions on the flotation activation of tantalum niobium ore (TNO) was studied by micro-flotation, adsorption capacity experiments, solution chemical composition calculations, and infrared spectral analysis. The experimental demonstrated that the combined collector of salicylhydroxamic acid (SHA) and ammonium dibutyl dithiophosphate (ADDP) resulted in a strong collection capacity for TNO in the presence of lead ions. The solution chemistry calculations determined that the dominant source of lead ions in the aqueous solution was $Pb(OH)^+$ at a pH of 8, which was conducive to the adsorption and interaction of SHA and ADDP anions. In the lead ion activation system, the combined reagent co-adsorbed onto the TNO surface, causing a large negative shift in the zeta potential. The co-adsorption mechanism of the combined collector consisted of complex chemisorption between SHA and the TNO surface active particles, while the main adsorption of ADDP is physisorption.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 29-38
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of mechanical and physicochemical properties of clinically retrieved titanium-niobium orthodontic archwires
Autorzy:
Stoyanova-Ivanova, Angelina
Cherneva, Sabina
Petrunov, Vladimir
Petrova, Violeta
Ilievska, Ivana
Mikli, Valdek
Iankov, Roumen
Powiązania:
https://bibliotekanauki.pl/articles/306480.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
właściwości mechaniczne
morfologia
struktura
skład chemiczny
Ni-free orthodontic wires
titanium-niobium
mechanical properties
morphology
chemical composition
structure
Opis:
Most of the orthodontic archwires used in the clinical practice nowadays contain nickel (Ni), however, many patients, especially kids, are allergic to Ni. One possible Ni-free alternative is the Titanium-Niobium (Ti-Nb) archwire. Unfortunately, there is not enough information about its mechanical properties in the literature, especially after clinical usage. Therefore, the aim of this work was to investigate and compare the mechanical properties, chemical composition, structure and morphology of as received and used in clinical practice Ti-Nb orthodontic archwires. Materials and methods: We investigated and compared as received and clinically retrieved after 4 and 6 weeks respectively Ti-Nb archwires with dimensions 0.43 × 0.64 mm (0.017 in. × 0.025 in.). The following methods were used: instrumented indentation testing (nanoindentation), X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Results: The nanoindentation investigations of as received and used Ti-Nb archwires revealed a decreasing in their indentation hardness with increased periods of use in the patient’s mouth. Moreover, an increasing of the concentration of Ti in the content of the TiNb alloy was associated with an increased period of use in the oral cavity. The SEM analysis showed changes in surface morphology with increasing the period of use of the archwires. Conclusions: The results showed that there are slight changes in the mechanical and physicochemical properties of the investigated wires after their use in the patient’s mouth. That is why we do not recommend them for recycling.
Źródło:
Acta of Bioengineering and Biomechanics; 2020, 22, 1; 31-39
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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