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Wyszukujesz frazę "water stability" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Water quality effects on a sulfidic PGM ore: Implications for froth stability and gangue management
Autorzy:
Manono, M. S.
Corin, K.
Wiese, J.
Powiązania:
https://bibliotekanauki.pl/articles/110603.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
entrainment
water quality
froth stability
electrolytes
Depressant behavior
Opis:
Polysaccharide depressants play a crucial role in the flotation of sulfidic PGM bearing ores as they prevent naturally floatable gangue (NFG) from reporting to the concentrate. This action is regarded as critically important because less dilution of the concentrate means lower costs for downstream processes. However, abnormal water conditions such as high concentrations of ions in the flotation system can modify the selectivity of these depressants. It is well known that the existence of selected electrolytes in water can alter the behaviour of some polysaccharide depressants by enhancing their adsorption onto gangue minerals and thereby prevent naturally floatable gangue from moving into the froth phase. Concurrently these same electrolytes may enhance frothability owing to their stabilising effect on the bubbles within the system. Plant water at various ionic strengths was investigated against sodium carboxymethyl cellulose (CMC) dosages in order to understand electrolyte-depressant interactive effects during the flotation of a Merensky ore in a batch flotation cell, using entrainment, rate of NFG recovery, and total gangue recovery as proxies. The study showed that the NFG recovery per unit mass of water decreased with increasing ionic strength at all CMC dosages, however the total amount of gangue reporting to the concentrate increased with increasing ionic strength at all CMC dosages. Thus, this paper considers the effects of both ionic strength and CMC dosage within flotation. It further investigates whether any interactive effects exist between froth stability and entrainment when considered simultaneously.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1253-1265
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Perspectives from literature on the influence of inorganic electrolytes present in plant water on flotation performance
Autorzy:
Manono, M. S.
Corin, K.
Wiese, J.
Powiązania:
https://bibliotekanauki.pl/articles/110721.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electrolytes
flotation reagents
froth stability
physicochemical interaction
water quality
Opis:
The interaction of inorganic electrolytes with reagents in the flotation of sulphidic PGM bearing ores is not well explored. It has been shown that specific inorganic electrolytes such as Ca2+ and SO42- can affect the wettability of gangue minerals. These could also hinder the adsorption of collectors onto valuable minerals and concurrently enhance or retard froth stability. This presents a challenge as regards understanding what the overarching or controlling mechanisms of interaction between electrolytes, reagents and minerals are as well as predicting how flotation performance will be affected. This review shows that studies in literature have simplified the question of electrolyte-reagent-mineral interactions and that current approaches have not provided fundamental solutions to the challenge of water quality. It is proposed that the complexity of the flotation system requires an in-depth knowledge of the individual electrolyte-reagent-mineral interactions so as to establish whether there are any dominant or synergistic interactions. Such in-depth knowledge should enable the development of pulp chemistry control measures against water quality variations in flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1191-1214
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular dynamics simulations study of nano bubble attachment at hydrophobic surfaces
Autorzy:
Jin, J.
Dang, L. X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/109533.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
molecular dynamics simulations (MDS)
film stability
bubble attachment
interfacial water structure
Opis:
Bubble attachment phenomena are examined using Molecular Dynamics Simulations (MDS) for the first time. The simulation involves a nitrogen nano bubble containing 906 nitrogen molecules in a water phase with 74,000 water molecules at molybdenite surfaces. During a simulation period of 1 ns, film rupture and displacement occurs. The attached nanobubble at the hydrophobic molybdenite face surface results in a contact angle of about 90º. This spontaneous attachment is due to a “water exclusion zone” at the molybdenite face surface and can be explained by a van der Waals (vdW) attractive force, as discussed in the literature. In contrast, the film is stable at the hydrophilic quartz (001) surface and the bubble does not attach. Contact angles determined from MD simulations are reported, and these results agree well with experimental and MDS sessile drop results. In this way, film stability and bubble attachment are described with respect to interfacial water structure for surfaces of different polarity. Interfacial water molecules at the hydrophobic molybdenite face surface have relatively weak interactions with the surface when compared to the hydrophilic quartz (001) surface, as revealed by the presence of a 3 Å “water exclusion zone” at the molybdenite/water interface. The molybdenite armchair-edge and zigzag-edge surfaces show a comparably slow process for film rupture and displacement when compared to the molybdenite face surface, which is consistent with their relatively weak hydrophobic character.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 89-101
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological stability of water in water distribution systems. The effect of water treatment trials
Autorzy:
Wolska, M.
Powiązania:
https://bibliotekanauki.pl/articles/206902.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
water treatment
carbon
groundwater
microorganisms
nitrogen removal
organic carbon
surface waters
water aeration
water distribution systems
water supply systems
biological stability
inorganic nitrogen
uzdatnianie wody
węgiel
wody gruntowe
mikroorganizmy
usuwanie azotu
węgiel organiczny
wody powierzchniowe
napowietrzanie wody
systemy dystrybucji wody
wodociągi
stabilność biologiczna
stężenie dwutlenku węgla
azot nieorganiczny
Opis:
Research into the removal efficiency of biogenic substances, necessary for the growth of heterotrophic microorganisms, was carried out for the following water treatment trials: surface water, infiltrative water and mixed surface water after microsieving with aerated underground water. The results have shown that the efficiency of removal of organic substances, independently of the type of treated water, increased along with the organic carbon concentrations in raw water. The average effectiveness of phosphate removal was: 92.1%, 88.8% and 83.7% for surface, infiltrative and mixed water, respectively. In all analyzed systems, presence of phosphates was an limiting factor for the regrowth of microorganisms in the distribution system. In none of the water treatment trials, effective removal of inorganic nitrogen has been recorded.
Źródło:
Environment Protection Engineering; 2015, 41, 2; 147-157
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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