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Wyszukujesz frazę "anatase" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Kinetics of sulphuric acid leaching of titanium from refractory anatase under atmospheric pressure
Autorzy:
Gao, Likun
Rao, Bing
Dai, Huixin
Xie, Haiyun
Wang, Peng
Ma, Fangtong
Powiązania:
https://bibliotekanauki.pl/articles/109701.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anatase ore
kinetics
sulphuric acid
leaching
titanium dioxide
Opis:
Anatase, as an important titanium resource, is attracting more and more attention in research and application. In this study, an efficient process of comprehensively extracting the titanium and other valuable elements from the anatase mineral was proposed. The effect of particle size, stirring speed, initial sulphuric acid concentration, solid-to-liquid ratio, and reaction temperature on the leaching rate of titanium from anatase was investigated. Under appropriate two-stage countercurrent leaching conditions, with the first stage of the liquid-to-solid ratio of 1/3 g/cm3, reaction temperature of 120 °C, initial acid concentration of 11 mol/dm3, residence time of 30 min, stirring speed of 200 rpm, and the second stage of the liquid-to-solid ratio of 1/3 g/cm3, reaction temperature of 200 °C, initial acid concentration of 13 mol/dm3, residence time of 30 min, and stirring speed of 200 rpm, over 99% TiO2, 99% Al2O3, and 97% Sc2O3 were extracted respectively with quartz still remained in the residue. X-ray diffraction, X-ray fluorescence spectrometer, and scanning electron microscopy/energy-dispersive spectroscopy were used to characterize the anatase samples before and after the leaching. Additionally, the leaching kinetics analysis indicated that both acid concentration and temperature were the most significant parameters for the leaching process. And, the titanium leaching reaction rate was controlled by the diffusion of reactants through the residual layer.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 467-478
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the mechanism and kinetics of sulfuric acid leaching scandium from rich scandium anatase
Autorzy:
He, Fei
Gao, Likun
Chen, Long
Rao, Bing
Shen, Hairong
Peng, Kebo
Gao, Guangyan
Powiązania:
https://bibliotekanauki.pl/articles/2146896.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anatase ore
sulfuric acid
leaching
kinetics
scandium
Opis:
Scandium and its compounds have excellent properties, and are widely used in cutting-edge fields such as optics, electronics, and alloys. Thus, scandium is an important strategic metal. However, scandium is extremely sparsely distributed in the earth's crust, rarely occurs as an independent mineral, and requires a complex recovery process. Therefore, the study of the extraction of scandium is of great practical significance. This study examined the leaching test and kinetics of scandium under the acid leaching system of refractory anatase ore. Under appropriate two-stage countercurrent leaching conditions, the first stage of the particle size of fraction of -0.074 mm 82.6%, initial H2SO4 concentration of 6 mol/L, leaching temperature of 100 °C, acid/solid ratio of 3 ml/g, stirring speed of 300 rpm, and leaching time of 50 min; and the second stage of the initial H2SO4 concentration of 11 mol/L, leaching temperature of 150 °C, acid/solid ratio of 4 ml/g, stirring speed of 300 rpm, and leaching time of 50 min, a scandium leaching rate of 96.98% was achieved. The kinetics of scandium leaching conformed to a shrinking-core model, and sulfuric acid concentration and temperature were the most important parameters affecting the scandium leaching rate. The kinetic analysis of scandium leaching at different sulfuric acid concentrations showed that as the concentration increased, the sulfuric acid leaching of scandium changed from being chemical reaction-controlled to internal diffusion-controlled, and the apparent reaction order was 1.2429. The kinetics of scandium leaching at different temperatures showed that the sulfuric acid leaching of scandium was reaction-controlled and the apparent activation energy was 42.21 kJ-mol-1.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 3; art. no. 146171
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption of sodium/calcium poly(acrylic acid) salts on anatase: effect of the polyelectrolyte molecular weight and neutralization
Autorzy:
Jacquemet, Christian
Powiązania:
https://bibliotekanauki.pl/articles/1449765.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
free energy
Langmuir isotherm
sodium-calcium poly(acrylic acid) salts
anatase
Opis:
Abstract: Interactions of poly(acrylic acid)s (PAAs) of two different molecular weights (Mw = 9,560 g×$mol^{-1}$ and 4,220 g×$mol^{-1}$) with surfaces of an untreated anatase $TiO_2$ were assessed through adsorption isotherm measurements. Those dispersants were tested under different sodium-calcium neutralization states (molar ratio $r = Ca^{2+}$ / $CO_{2-}$ varying from 0 to 0.35). Their behavior towards the $TiO_2$ surfaces can be described by the Langmuir adsorption model. For both polymers, surface coverage ($Γ_max$) evolves linearly with the molar ratio $r$. For a given r value, a lower surface coverage was observed with the polymer having the highest molecular weight. The free energy of adsorption ($/DeltaG_{ads}$) of PAAs was estimated from adsorption experiment data. This calculation indicates that sorption occurs spontaneously and is unlikely to be of chemical nature. The absolute values of $/DeltaG_{ads}$ are higher for the highest molecular weight polymers suggesting that they are more strongly adsorbed to anatase surfaces. The absolute values of $/DeltaG_{ads}$ per mole of sodium-calcium macromolecules are found to be lower than those calculated for their homologues 100% sodium neutralized suggesting that they are bound with the solid by a fewer number of segments.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 113-123
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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