Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "SO2" wg kryterium: Wszystkie pola


Wyświetlanie 1-8 z 8
Tytuł:
Reactivity of marble wastes for potential utilization in wet flue gas desulphurization
Autorzy:
Altun, N. E.
Powiązania:
https://bibliotekanauki.pl/articles/110132.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
marble
reactivity
thermal power production
SO2
desulphurization
Opis:
Wastes of most marble types are distinguished with their superior CaCO3 content and potential to utilize them as an alternative to limestone. Control of SO2 using marble wastes in wet flue gas desulphurization (WFGD) units of coal fired thermal power plants is an important opportunity. In this study, nine types of marble wastes were evaluated in terms of their ability to dissolution (reactivity) in an acidic environment. The reactivity was expressed as fractional conversion with time with respect to the chemical composition and particle distribution of wastes as well as temperature and pH of solution. Dissolution reaction rate constants were also computed. Reactivity of the wastes varied significantly with chemical compositions of the marble types. The same marble type displayed different dissolution profiles as a function of test conditions (fineness, temperature, pH). Higher contents of CaCO3 and Fe2O3 positively influenced dissolution ability and rates, whereas increased MgCO3 content had adverse effects. The changes in particle size, temperature and pH influenced the reactivity. The reactivity increased with decreasing particle size. Also, higher temperature and increased acidity favored dissolution ability of the marble wastes. Our results showed that under optimized conditions marble wastes, having a higher content of CaCO3 and low content of MgCO3, are potential SO2 sorbent alternative.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 497-509
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of $Ca{2+}$ and $SO_4^{2-}$ ions on fluorite flotation
Autorzy:
Xun, Luobing
Hu, Jiacheng
Shi, Qing
Zhang, Guofan
Powiązania:
https://bibliotekanauki.pl/articles/1448205.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fluorite
flotation
calcium cation
sulphate anion
Opis:
The effects of $Ca^{2+}$ and $SO_4^{2-}$ on the flotation behaviour of fluorite with sodium oleate as a collector and the underlying mechanism by which these effects were investigated via micro-flotation experiments, solution chemistry calculations, and X-ray photoelectron spectroscopy. The results indicated that the addition of $SO_4^{2-}$ and $Ca^{2+}$ inhibited fluorite flotation and the inhibition effect was increased by the addition of pH. This was mainly due to the increase of the sulphate-containing components in the solution and the adsorption of $SO_4^{2-}$ on the surface of fluorite. With the increase of pH, the alkalinity of the solution increases, OH- and more $SO_4^{2-}$ are further adsorbed on the fluorite surface, thereby reducing the recovery of fluorite flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 2; 95-104
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Leaching of manganese ores using corncob as reductant in H2SO4 solution
Autorzy:
Ali, S.
Iqbal, Y.
Farooq, U.
Ahmad, S.
Powiązania:
https://bibliotekanauki.pl/articles/110165.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
siliceous manganese ore
characterization
leaching
corncob
H2SO4
Opis:
In this study, corncob was used as reductant for sulfuric acid leaching of manganese ore from Daweezi, Upper Mohmand Agency, Pakistan. X-ray diffraction of representative powdered samples revealed the presence of manganese silicate MnSiO(SiO4), calcite (CaCO3), and -quartz (SiO2). X-ray diffraction and energy dispersive spectroscopy analyses indicated that the examined manganese ore was siliceous in nature. Three process parameters were investigated in the present study including the particle size of the ore, leaching temperature, and amount of corncob. Manganese extraction of 92.48 wt% was achieved for a leaching time of 60 min at 90 oC using 1.9 mol/dm3 H2SO4 concentration and 4 g of corncob. The present results demonstrated that corncob is a low cost, renewable, and non-hazardous reducing agent for manganese leaching under mild acid conditions in comparison to the other available reagents.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 56-65
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the use of $Na_2SO_3$ as a pyrite depressant in saline systems and the presence of kaolinite
Autorzy:
Arancibia-Bravo, María P.
Lucay, Freddy A.
Sepúlveda, Felipe D.
Cisternas, Luis A.
Powiązania:
https://bibliotekanauki.pl/articles/1446523.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Na2SO3
IPETC
clays
flotation
saline solution
artificial neural networks
Opis:
The effect of Na2SO3 as a pyrite depressant in NaCl and KCl saline media and the presence of kaolinite were evaluated by zeta potential tests. Chalcopyrite was also included in the study, because pyrite usually accompanies this mineral. Subsequently, the floatability results of both minerals in the NaCl solution were optimized based on the design of experiments (DoE). The Box–Behnken DoE was applied considering the percentage of kaolinite $(X_1)$, collector dose $(X_2)$, and depressant dose $(X_3)$ as factors. The results were modeled using artificial neural networks (ANNs) to construct contour plots and to determine the optimal conditions. In particular, maximization of the mass recovery of chalcopyrite and minimization of that of pyrite were sought. The particle swarm optimization algorithm was used as an optimization technique. The results indicated that the optimal conditions to maximize the floatability of chalcopyrite were kaolinite 6.85%, collector dose $3.58 × 10^{–3} mol$ / $dm^3$, and depressant dose $3.49 × 10^{–5} mol$ / $dm^3$. On the contrary, the optimal conditions to minimize the floatability of pyrite were 5% kaolinite, collector dose $5 × 10^{–4} mol$ / $dm^3$, and depressant dose $6.4 × 10^{–5} mol$ / $dm^3$. Under these conditions, the mass recoveries of chalcopyrite and pyrite were 66.1% and 14.0%, respectively. The results also indicated that the presence of kaolinite negatively affects the flotation of chalcopyrite, while the effect of $Na_2SO_3$ is not significant. In general, the findings suggest that $Na_2SO_3$ is a viable alternative to consider as a pyrite depressant in saline environments.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 168-179
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of activity coefficient and equilibrium constant models on the speciation of aqueous solutions of H2SO4–MgSO4–Al2(SO4)3 at 235 and 250 °C
Autorzy:
Dickson, Okechukwu Vincent
Deleau, Thomas
Coquelet, Christophe
Espitalier, Fabienne
Lombart, Julien
Tardy, Antoine
Powiązania:
https://bibliotekanauki.pl/articles/24085644.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
activity coefficient
equilibrium constant
hydrometallurgy
speciation
thermodynamics
Opis:
Supersaturation occurs in many industrial applications promoting reactive crystallisation between the reactants to form solutes. These solutes accumulate during precipitation, leading to the formation of scales on the inner walls of the reactor and particularly around the stirrer, causing modifications in the hydrodynamics. This encrustation is responsible for process shutdowns in continuous crystallisation processes. Supersaturation control is essential for industrial processes aimed at controlling or inhibiting the formation of these solids. Knowledge of mineral solubility and chemical speciation is required to account for the composition of the complexes in the system in their various solid or aqueous forms. This speciation is obtained by considering the thermodynamic equilibrium constants of the dissociation/complexation reactions involved in the system, the pressure, and the activity coefficients of the chemical species in their molecular or electrolyte form. From these thermodynamic quantities and the state of the system, we can predict the direction of the reaction. This study highlights the risk of the lack of experimental information on equilibrium constants at high temperatures and moderate pressures. Our goal is to evaluate the accuracy of existing models classically used to predict the equilibrium constant in such very hard conditions encountered in hydrometallurgical processes. Furthermore, we demonstrate the influences of equilibrium constants estimation and activity coefficient models on the speciation of H2SO4–Al2(SO4)3–MgSO4 systems, forming hydronium alunite and kieserite in the laterite liquor of hydrometallurgical processes.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 167497
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decomposition of the Kenticha mangano-tantalite ore by HF/H2SO4 and KOH fusion
Autorzy:
Berhe, G. G.
Velázquez del Rosario, A.
Tadesse, B.
Yimam, A.
Woldetinsae, G.
Powiązania:
https://bibliotekanauki.pl/articles/109478.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
decomposition
Kenticha pegmatite
mangano-tantalite
Ta
Nb
Opis:
In this study, the decomposition behavior of Ta and Nb from the mangano-tantalite ore was investigated using HF/H2SO4 mixture and KOH fusion. The effects of reaction time, decomposition temperature, acid and alkaline concentrations, and particle size on the dissolution process were examined. Higher decomposition rates were achieved at 6:2 mol/dm3 ratio of HF and H2SO4, and with the addition of 10 g KOH in the alkali fusion step. In addition, similar trends in decomposition rates between two agents (HF/H2SO4 and KOH) and comparable dissolution performances were observed. The increase in the decomposition temperature initially increased the decomposition rate of mangano-tantalite for the two systems considered in this study. However, no significant change in the leaching rate of Ta and Nb was observed beyond 50 °C for the HF/H2SO4 system and above 400 °C when using the KOH fusion process. The elemental and compositional analyses of the leached residues using XRF, XRD, and FT-IR spectroscopy indicated that the acid (mixture of HF and H2SO4) decomposition resulted in slightly better dissolution performance for Ta compared with the alkaline fusion method. Overall, the results indicated that KOH can be a suitable alternative decomposition agent to the volatile, corrosive and toxic HF in the hydrometallurgical processing of tantalite ores.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 406-414
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective extraction of vanadium from vanadium-titanium magnetite concentrates by non-salt roasting of pellets-H2SO4 leaching process
Autorzy:
Luo, Yi
Che, Xiaokui
Wang, Haixia
Zheng, Qi
Wang, Lei
Powiązania:
https://bibliotekanauki.pl/articles/1445902.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vanadium-titanium magnetite
pellets
selective extraction
sulfuric acid leaching
Opis:
In this work, a novel process of pellet non-salt roasting and H2SO4 leaching was proposed for the selective extraction of vanadium from vanadium–titanium magnetite concentrate. Vanadium can be leached but the iron impurity was maintained in the pellets. Moreover, the leached pellets can meet the quality requirements of the iron-making process after secondary roasting, realizing comprehensive utilization. The maximal vanadium leaching efficiency was up to 60.3%, whereas 0.17% of the iron impurity was leached. The optimum conditions of pellet roasting and leaching were obtained by single-factor experiments. The X-ray diffraction and scanning electron microscopy–energy disperse X-ray spectrometry analyses showed that the vanadium iron spinel can be oxidized and decomposed into Fe2O3 and vanadate during the roasting process. Given that dilute sulfuric acid can react with vanadate without reacting with Fe2O3 in the leaching process, selective vanadium extraction was realized. This work provides new insights into the industrial production of vanadium–titanium magnetite concentrate involving the direct extraction of vanadium.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 36-47
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New insights into the promotion mechanism of $(NH_4)_2SO_4$ in sulfidization flotation: a combined experimental and computational study
Autorzy:
Chen, Daixiong
Liu, Mengfei
Hu, Bo
Dong, Yanhong
Xue, Wei
He, Peng
Chen, Fang
Zhu, Jianyu
Zhang, Chenyang
Powiązania:
https://bibliotekanauki.pl/articles/1446762.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
malachite
promotion
sulfidization
flotation
mechanism
Opis:
Ammonium sulfate ((NH4)2SO4) exhibits promoting effects in malachite sulfidization flotation. However, the promotion mechanism remains poorly understood. In this study, micro-flotation tests, zeta-potential measurements, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and materials studio simulation (DFT) were used to investigated the promotion mechanism of $(NH_4)_2SO_4$. Micro-flotation test demonstrates that the recovery of malachite from 73% increased to 83%, when the (NH4)2SO4 was added. Contact angle and zeta potential test results indicate that addition of $Na_2S•9H_2O$ changes the surface properties of malachite and provide the conditions for adsorption of butyl xanthate (BX). After promoting the sulfidization by $(NH_4)_2SO_4$, BX is more effective in improving the hydrophobicity. SEM-EDS and AFM results show that $(NH_4)_2SO_4$ can improve performance and stability of sulfidization. X-ray photoelectron spectroscopy indicates that after sulfidization, polysulfides and cuprous were appeared in malachite surface, infers that a redox reaction occurs between sulfur and copper on the surface of malachite. After addition of $(NH_4)_2SO_4$, the percentage of polysulfides and cuprous were increased, it implies $(NH_4)_2SO_4$ can accelerate the redox reaction. Computational results show that after adding $(NH_4)_2SO_4$, the adsorption energy of HS- on the malachite surface is reduced, implies that $(NH_4)_2SO_4$ can improve the stability of HS-adsorption on the surface of malachite.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 5; 57-70
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies