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Wyszukujesz frazę "celestite" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Celestite upgrading by jigs in presence of steel balls as ragging material
Autorzy:
Sobhy, Ahmed
El-Midany, Ayman A.
Ibrahim, Susan S.
Powiązania:
https://bibliotekanauki.pl/articles/1447020.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
celestite
calcite
jigging
ragging material
gravity separation
statistical analysis
Opis:
Gravity separation using jigs is widely used for coarse particle sizes separation. However, fine sizes reduce jig performance. In this study, the upgrading of celestite ore by jig was investigated at different size fractions in the presence of ragging material. Three size fractions, i.e., -15+2 mm, - 2.0 + 0.50 mm and - 0.50 + 0.08 mm were used. The steel balls were used, as ragging material, to improve the separation of fines as well as to improve the concentrate quality. The statistical design was used to correlate celestite grade and recovery with studied operating variables, i.e., the ragging number of layers, ragging balls diameter, and separation time, at a fixed water flow rate and stroke length. The design results indicated that the ragging balls diameter and their number of layers play an important role. The smaller the ragging balls diameter and the higher the ragging number of layers are the better the concentrate grade but the longer the separation time. A celestite concentrate of (> 95% SrSO4) with 74.5% recovery was obtained for - 2.0 + 0.50 mm size fraction at the optimum conditions; i.e., 3.1 mm ragging balls diameter, one ragging layers, and 15 minutes separation time.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 5; 118-128
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechano-chemical conversion of celestite in highly concentrated sodium carbonate media
Autorzy:
Sezer, Raşit
Arslan, Cüneyt
Powiązania:
https://bibliotekanauki.pl/articles/109788.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
celestite
wet milling
direct conversion
response surface methodology
strontium carbonate
Opis:
An effect of high-energy ball milling on the mechano-chemical conversion of celestite to strontium carbonate (SrCO3) was studied. A celestite ore was ground by a planetary ball mill in a highly concentrated sodium carbonate (Na2CO3) solution. The experimental study was carried out to determine the effects of milling time (15, 30, and 45 min) and Na2CO3 concentration (1, 1.25, and 1.5 M) on the particle size and SrCO3 percentage of the product. A celestite/ball weight ratio was selected as 1/10 and the volume of carbonate solution was calculated for the stoichiometric amount of sulfate in celestite, as constant. After filtering, washing and drying the precipitated SrCO3 sludge was analyzed by XRD, SEM-EDS. Powders were leached in HCl solution and analyzed by AAS in order to determine the SrCO3 amount in the product. A response surface methodology was applied via the Box-Behnken method for the results of particle size and SrCO3 percentage. Regression model coefficients were 98.61 and 98.14%, which were the results of compatibility as experimentally obtained and predicted by the model, respectively. The maximum amount of SrCO3, 96.84% and the minimum particle size, 10.297 μm were obtained with the maximum values of the parameters, 45 min, 1.5 M Na2CO3, and 450 rpm.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 324-335
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The tube wall of Cambrian anabaritids
Autorzy:
Kouchinsky, A
Bengtson, S.
Powiązania:
https://bibliotekanauki.pl/articles/22467.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Anabaritida
biomineralization
recrystallization
skeleton
tube wall
wall structure
aragonite
celestite
barite
Siberia
anabaritid
Cambrian
paleozoology
Opis:
Celestite/barite−replaced and phosphate−replicated tubes of Early Cambrian anabaritids from the northern part of the Siberian Platform (Anabar Shield) give new evidence on the wall−structure of these enigmatic fossils. The walls consist of fibres, interpreted as reflecting an original aragonitic fabric. Bundles of fibres are arranged in growth lamellae, and the latter form an angle of at least 45° with the inner tube wall. Where the outer tube surface projects into annular flanges, the lamellae have a chevron−like section due to the backwards deflection of the outer parts. Anabaritids are usually referred to the Cnidaria or left without systematic assignment, but earlier suggestions included affinity to the serpulid polychaetes. The chevron structure resembles that previously exclusively known from serpulids, but the presence of internal tooth−like structures in anabaritid tubes, perhaps compromising up−and−down movement through the tubes, continue to make a direct assignment to the Serpulida questionable.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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