Wszystkie pola: pyrite surface - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Adsorption Behavior of Glucuronic Acid on Pyrite Surface: an electrochemical and DFT Study
Autorzy:: Ning, Xu Jia
Ying, Yang Hong
Lin, Tong-Lin
Powiązania:: https://bibliotekanauki.pl/articles/355049.pdf
Data publikacji:: 2020
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: glucuronic acid
pyrite
adsorption
Opis:: Bacterial adsorption on mineral surface is one of the key steps in bioleaching process. The bacteria adsorb on the mineral surface via the extracellular polymeric substances (EPS) layer. In this paper, the behavior of glucuronic acid, one of the key substances in EPS layer, adsorbed on the pyrite surface is studied using DFT and electrochemical methods. Adsorption capacity of glucuronic acid is stronger than that of water. Glucuronic acid adsorbs on pyrite surfaces and it follows a mixed type of interactions (physisorption and chemisorption). Adsorption of glucuronic acid on pyrite surface followed Langmuir’s adsorption isotherm with adsorption standard free energy of –27.67kJ mol^-1. The structural and electronic parameters were calculated and discussed.
Źródło:: Archives of Metallurgy and Materials; 2020, 65, 1; 433-440
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Evaluation of Contact Angle on Pyrite Surface
Wyznaczanie kąta zwilżania na powierzchni pirytu
Autorzy:: Koval, L.
Matysek, D.
Powiązania:: https://bibliotekanauki.pl/articles/318336.pdf
Data publikacji:: 2014
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Tematy:: contact angle
pyrites
potassium and sodium xanthates
sessile drop method
kąt zwilżania
piryt
ksantogeniany potasu i sodu
metoda osadzonej kropli
Opis:: In the present paper, the contact angle measurements using six different xanthate solutions and distilled water were studied on twelve polished pyrite surfaces using sessile drop method. The 10% solutions of three potassium and three sodium xanthates were used. The pyrite samples from six countries and ten different deposits were utilized. The chemical composition of pyrites was studied using EDX microanalysis which proved that pyrite samples were not heterogenic. No relation or dependence between the contact angle and the chemical composition (i.e., Fe:S ratios) was found. The average values of contact angles measured using potassium and sodium xanthates were lower than the values of contact angle measured using distilled water. From these measurements can be concluded, that the pyrite samples are favourably wetted by either potassium or sodium xanthates than distilled water in flotation environment. The comparison of potassium and sodium xanthates showed better suitability of the potassium xanthates for the possible pyrite flotation (lower contact angle was measured on eight out of twelve samples for potasium xanthates). Pyrite samples Sokolov, Jachymov and Kutna Hora showed the lowest average contact angle values from all xanthates using potassium amyl xanthate (PAX) with average values of 34,80°, 42,94° and 31,01° respectively. The sodium xanthates would be more appropriate for the Navajun 2 and 3, Jachymov Sadon, and Norilsk pyrite samples. Very small differences in average contact angle values were obtained when potassium/sodium ethyl and isobutyl xanthates were compared. The minimum average values of contact angle for six out of twelve samples and for five out of eight samples in hydrothermal deposits were measured using ethyl xanthates what makes them the most suitable collectors for the pyrite samples from hydrothermal deposits and for pyrites in general. Even smaller variation in the results was showed using isobutyl xanthates with the highest average values of contact angle what makes them not suitable as the collectors for pyrite samples used in this study. The average value of contact angle measured using SIBX was 58,50°.
W pracy tej badano pomiary kąta zwilżania z użyciem trzech różnych roztworów ksantatui wody destylowanej na dwunastu polerowanych powierzchniach pirytu za pomocą metody osadzania kropli. Użyty został 10% roztwór trzech ksantatów potasu i trzech ksantatów sodu. Wykorzystane zostały próbki pirytu z sześciu państw i dziesięciu różnych depozytów. Skład chemiczny pirytów był zbadany za pomocą mikroanalizy EDX, która udowodniła, że próbki pirytu nie były heterogeniczne. Nie znaleziono żadnej relacji lub zależności między kątem zwilżania i składem chemicznym (np. stosunku Fe:S). Średnie wartości kąta zwilżania zmierzone z użyciem ksantatów potasu i sodu były niższe niż wartości kąta zwilżania zmierzone z użyciem wody destylowanej. Z pomiarów tych można wnioskować, że próbki pirytu są łatwiej zwilżane za pomocą ksantatów potasu lub sodu niż za pomocą wody destylowanej w środowisku flotacyjnym. Porównanie ksantatów potasu i sodu wykazało lepszą przydatność ksantatu potasu w możliwej flotacji pirytu (niższy kąt zwilżania został zmierzony w ośmiu z dwunastu próbek dla ksantatu potasu). Próbki pirytu Sokolov, Jachymov i Kutna Hora wykazały najniższe średnie wartości kąta zwilżania ze wszystkich ksantatów z użyciem potasowego amylu ksantatu (PAX) ze średnimi wartościami odpowiednio 34,80°, 42,94° i 1,01°. Ksantaty sodu mogą być bardziej odpowiednie dla próbek pirytu Navajun 2 i 3, JachymovSadon i Norilsk. Bardzo małe różnice w wartościach średnich kąta zwilżania zostały uzyskane gry potasowy lub sodowy etyl i izobutyl ksantatu były porównywane. Minimalne średnie wartości kąta zwilżania dla sześciu z dwunastu próbek i na pięciu z ośmiu próbek z depozytów hydrotermalnych były zmierzone z użyciem etylu ksantatu co czyni je najbardziej odpowiednimi kolektorami dla próbek pirytu z depozytów hydrotermalnych i pirytów w ogóle. Jeszcze mniejsze wahania wyników wykazano używając izobutylu ksantatów lecz uzyskano najwyższe średnie wartości kąta zwilżania co czyni je niewłaściwymi kolektorami dla próbek pirytu użytych w tym badaniu. Średnia wartość kąta zwilżania zmierzonego z użyciem SIBX wynosiła 58,50°.
Źródło:: Inżynieria Mineralna; 2014, R. 15, nr 2, 2; 119-125
1640-4920
Pojawia się w:: Inżynieria Mineralna
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Galvanic contacting effect of pyrite on xanthate adsorption on galena surface: DFT simulation and cyclic voltammetric measurements
Autorzy:: Ke, B.
Chen, J.
Li, Y.
Chen, Y.
Powiązania:: https://bibliotekanauki.pl/articles/110904.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: adsorption
DFT
galvanic interaction
pyrite surface
galena surface
cyclic voltammetric measurements
Opis:: The effect of galvanic interaction between pyrite and galena on xanthate adsorbing on the galena surface has been investigated by means of density functional theory (DFT) and cyclic voltammetric measurements. The calculated results show that differences in the contact site and contact distance between galena and pyrite can affect the intensity of the galvanic interaction, and the relationship between the intensity of galvanic interaction and the adsorption ability of xanthate on galena surface has been studied in detail. In general, the galvanic interaction between pyrite and galena surface can enhance the adsorption of xanthate on the galena surface. The adsorption energies of xanthate on the galena surface decrease with the decrease of contact distance, and when the contact distance is lower than 4 Å, the adsorption energies decrease significantly at Pb-Pb, Pb-S and S-S sites. In particular, at the contact distance of 3 Å, a sharp decrease of adsorption energy is observed at the Pb-Pb contact site; in this case, the negative shift of the Pb-S bonding range and DOS non-locality at Pb-Pb contact site are significantly greater than that of the S-S or Pb-S contact sites. The cyclic voltammetric measurements reveal that the galvanic interaction between galena and pyrite improves the adsorption of xanthate on galena surface, which is in good agreement with the DFT results.
Źródło:: Physicochemical Problems of Mineral Processing; 2018, 54, 3; 826-836
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: First-principles study on the adsorption structure of water molecules on a pyrite (100) surface
Autorzy:: Liu, Yingchao
Chen, Jianhua
Li, Yuqiong
Zhang, Junjie
Kang, Duan
Powiązania:: https://bibliotekanauki.pl/articles/1447970.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: pyrite
water molecules
adsorption
Opis:: The hydration structure of water molecule adsorption at different coverages of a monolayer on a pyrite (100) surface were simulated using the density functional theory (DFT) method. The results demonstrate that the Fe-O interaction weakens and the adsorption energy per water molecule decreases with increasing water coverage, except at a monolayer coverage of 12/12 (i.e., full coverage). H-S and H-O hydrogen bonds were formed on the nearest surface layer. When large amounts of water molecules adsorb onto the surface, the adsorbed water molecules can be divided into three layers: the layer nearest to the surface, the second nearest to the surface, and the layer farthest from the surface. The thickness of the former two layers is approximately 5.5 Å. The three layers have water densities of 1.12 g/cm3, 1.08 g/cm3, and 0.95 g/cm3, respectively, suggesting that there is a strong interaction between the pyrite surface and water molecules and the influence of surface structure on water adsorption reaches a distance of more than 10 Å. Dynamics simulations suggest that the water molecules close to the mineral surfaces are in an orderly arrangement while those far from the surface are disordered.
Źródło:: Physicochemical Problems of Mineral Processing; 2021, 57, 2; 121-130
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Adsorption mechanism of copper xanthate on pyrite surfaces
Autorzy:: Deng, Zhengbin
Cheng, Wanli
Tang, Yun
Tong, Xiong
Liu, Zhihong
Powiązania:: https://bibliotekanauki.pl/articles/1447276.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: pyrite
cupric xanthate
cuprous xanthate
adsorption
surface
Opis:: The ratio of the hydrophobic to hydrophilic species and their distribution on mineral surfaces significantly influences the floatability of sulfide minerals. Through the flotation test, the influence of different reagents on pyrite flotation was examined. The interaction mechanisms between copper xanthate and pyrite were evaluated using advanced analysis technologies, including contact angle measurements, zeta potential analysis, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results show that the butyl xanthate in solution reacts with copper sulfate to form cupric xanthate, increasing the consumption of the collector butyl xanthate and resulting in lower floatability of pyrite. Cupric xanthate can be adsorbed on the pyrite surface through bonding with the sulfur sites. The adsorbed cupric xanthate on the pyrite surface undergoes redox reaction. The cupric xanthate is reduced to cuprous xanthate, and the sulfur on the surface will be oxidized. The adsorption products on the pyrite surface contain both cuprous xanthate and cupric xanthate. As the pH of a solution increases, the absolute value of the zeta potential of pyrite surface increased and the surface contact angle increased. Iron xanthate is also formed on the pyrite surface through a chemical reaction between the xanthate ions and pyrite, oxidation of xanthate ions to dixanthogen also takes place. Cuprous xanthate is the main hydrophobic substance on the pyrite surface, which can change the surface electrical properties and wettability of pyrite, and improve hydrophobicity of pyrite.
Źródło:: Physicochemical Problems of Mineral Processing; 2021, 57, 3; 46-60
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Interaction between sphalerite and pyrite and its effect on surface oxidation of sphalerite
Autorzy:: Yang, B.
Xie, X.
Tong, X.
Lan, Z.
Cui, Y.
Powiązania:: https://bibliotekanauki.pl/articles/109553.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: sphalerite
surface oxidation
minerals interaction
DFT
Opis:: The interaction between sphalerite and pyrite was investigated by dissolution test, X-ray photoelectron spectroscopy (XPS), zeta potential measurement and density functional theory (DFT) calculation. Dissolution tests indicated that sphalerite dissolution was promoted due to the galvanic interaction between sphalerite and pyrite. The Zn2+ ion concentration increased with increasing pyrite content and dissolved time. XPS analysis results demonstrated that a new oxidation product was formed on the sphalerite surface in the presence of pyrite in a pulp. Zeta potential measurements showed that the isoelectric point of sphalerite increased from 3.3 to 5.4 due to galvanic interaction. DFT calculation results suggested that electron transfer from sphalerite to pyrite occurred when they contacted. The Zn 4s and S 3p states of sphalerite lost electrons. The Fe 4p and 4s of pyrite states obtained electrons, and Fe 3d and S 3s states lost a small number of electrons. The surface oxidation of sphalerite was promoted due to the interaction with pyrite, and the collectorless floatability of sphalerite decreased.
Źródło:: Physicochemical Problems of Mineral Processing; 2018, 54, 2; 311-320
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Insight into the effect of galvanic interactions between sulfide minerals on the floatability and surface characteristics of pyrite
Autorzy:: Yang, Bo
Tong, Xiong
Xie, Xian
Huang, Lingyun
Powiązania:: https://bibliotekanauki.pl/articles/1448232.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: galvanic interaction
floatability
pyrite
sulfide minerals
Opis:: Complex sulfide ores are usually found as a mixture of various sulfide and gangue minerals, and froth flotation is the predominant method for the selective separation of sulfide minerals. Adherence and contact between sulfide minerals are inevitable during froth flotation, and galvanic interactions between sulfide minerals will occur because of differences in rest potentials. However, the effect of these galvanic interactions on the selective flotation of sulfide minerals have been rarely studied. In this work, the effect of the galvanic interaction between pyrite and sphalerite on the flotation behavior and surface characteristics of pyrite was investigated by micro-flotation tests, collector adsorption tests, electrochemical techniques and XPS (X-ray photoelectron spectroscopy) surface analysis. The micro-flotation tests indicated that the floatability of pyrite decreased in the pH range of 4.0 to 9.5 and increased under strongly alkaline pH conditions (pH > 10) due to the galvanic interaction. The collector adsorption results demonstrated that the adsorption capacity of the collector on the pyrite surface was significantly reduced because of the galvanic interaction between pyrite and sphalerite. The electrochemical measurements revealed that the decrease in the oxidation current of xanthates to dixanthogen was responsible for the decreasing adsorption capacity of the collector on the pyrite surface. The XPS results indicated that the formation of the $S_O_3^{2-}$ oxidation product on the pyrite surface decreased at a strongly alkaline pH due to the galvanic interaction. Therefore, pyrite floatability improved at an alkaline pH. These results consistently showed that the galvanic interaction between pyrite and sphalerite had an important influence on the floatability and surface characteristics of pyrite.
Źródło:: Physicochemical Problems of Mineral Processing; 2021, 57, 2; 24-33
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Ammonium chloride’s weakening effect on the copper activation of pyrite in flotation and the surface regulation mechanism behind it
Autorzy:: Zhang, Shengdong
Chen, Yumeng
Tong, Xiong
Xie, Xian
Lu, Yalin
Powiązania:: https://bibliotekanauki.pl/articles/110323.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: pyrite
depression
cuprammonium solution
pH buffering property
flotation
Opis:: The traditional separation process of pyrite and marmatite is carried out under highly alkaline conditions. Therefore, a large amount of lime is demanded and the zinc recovery cannot be guaranteed. However, under weakly alkaline conditions, copper-activated pyrite has good floatability, which is difficult to separate from marmatite. In this paper, ammonium chloride (NH₄Cl) is used for depressing the flotation of copper-activated pyrite to achieve the separation of these two minerals under weakly alkaline environment. The flotation tests show that NH₄Cl can significantly reduce the floatability of pyrite in weakly alkaline conditions. The results of adsorption tests and X-ray photoelectron spectroscopy (XPS) analyses indicate that NH₄Cl can obviously change the composition of pyrite surface by increasing the content of iron/copper hydroxide and reducing the content of copper sulfides. Calculation of the solution composition demonstrates that the addition of NH₄Cl results in the occurrence of Cu(NH₃)n²⁺ and the pH buffering property. Based on these results, it can be concluded that the depression of NH₄Cl on copper activated pyrite is mainly derived from two aspects: 1) the pH buffering property of the conjugated acid-base pair (NH₄₊/NH₃) can impede the decline of OH- concentration, which results in more hydroxide adsorbed on pyrite; 2) NH₃ (aq) competes with the pyrite surface to consume Cu²⁺through complexation, which causes a reduction in the amount of copper sulfides formed on the pyrite surface.
Źródło:: Physicochemical Problems of Mineral Processing; 2019, 55, 5; 1070-1081
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Dispersive effect of low molecular weight sodium polyacrylate on pyrite-serpentine flotation system
Autorzy:: Zhao, K.
Yan, W.
Wang, X.
Gu, G.
Deng, J.
Zhou, X.
Hui, B.
Powiązania:: https://bibliotekanauki.pl/articles/110158.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: dispersant
serpentine
flotation
surface potential
dispersion mechanism
Opis:: In this work, the dispersive effect of low molecular weight sodium polyacrylate (PAAS) on serpentine, and its dispersion mechanism were systematically investigated through zeta potential measurements, micro and batch flotation as well as adsorption tests. At pH 5, where flotation of iron sulphide was routinely performed, pyrite and serpentine minerals were oppositely charged, and therefore they were attracted to each other. Slime coatings of serpentine adhered to the surface of pyrite, decreasing the adsorption density of a collector on the pyrite surface, but also reducing the flotation recovery. PAAS increased the flotation recovery of pyrite by promoting dispersion between pyrite and serpentine. The effective flotation separation of pyrite from the refractory iron sulphide ore was possible by using PAAS as a dispersant. Anionic PAAS adjusted the surface potential of serpentine through adsorption on the serpentine surface and changed the interaction between pyrite and serpentine particles from attractive to repulsive, and then dispersed pyrite and serpentine.
Źródło:: Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1200-1213
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Adsorption of yeast dextran on clinochlore surface and the implications for pyrite/clinochlore separation
Autorzy:: Wang, Zhen
Zou, Dan
Zhao, Kaile
Safarov, Sayfidin
Xu, Ying
Powiązania:: https://bibliotekanauki.pl/articles/2146917.pdf
Data publikacji:: 2022
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: clinochlore
pyrite
flotation
yeast dextran
adsorption
Opis:: Silicate minerals with a certain degree of flotability are often easy to mix into sulfide ore concentrate in mineral processing industry. In this paper, the adsorption of yeast dextran on clinochlore and its application in pyrite/clinochlore separation were investigated. The adsorbed amount and micro polarity measurement results displayed that the yeast dextran molecules selectively adsorbed onto clinochlore surface compared with pyrite. The adsorbed yeast dextran resulted in the increase in the surface polarity of clinochlore surface, and inhibited the further adsorption of xanthate, thus keep it hydrophilic and depressed. Quantum chemical computation results indicated that yeast dextran was mainly adsorbed on mineral surface by the chelation with the surface metal active sites, and the chelating strength of yeast dextran with three ions was in the sequence of Fe3+ > Mg2+ > Fe2+. While Mg2+, Fe2+ and Fe3+ are the main metal ions on the surface of clinochlore, and Fe2+ is the unique metal ions on pyrite surface. This is the reason of the selectivity of the yeast dextran depressant for pyrite/clinochlore flotation system. The flotation results demonstrated that yeast dextran was qualified to selectively depress clinochlore in pyrite flotation.
Źródło:: Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 151635
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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