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1

Comparison of anionic, cationic and amphoteric collectors used in pyrite flotation

Bulut Gülay, Sirkeci A. A., Arı Beril

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 5

15--22

EN

In this study, flotation tests were conducted with purified pyrite and ore samples. The collectors employed were anionic and cationic type such as potassium ethlyl-amyl xanthate, Tomamine M73 and Resanol Bal. According to the flotation tests, it was found that pyrite floated at low pH and depressed at high pH values with xanthates. On the other hand, in the case of cationic collectors which are Tomamine M73 (alkyl ether amine, an amphoteric surfactant) and Resanol Bal (N-3-tridecyloxy propyl 1-3 diamine, branched acetate) pyrite floated at high pH values. It was shown that amine type collectors could be efficient to selectively float pyrite from chalcopyrite at alkali pH ranges in the case of ore samples.

2

Preparation, characterization and photocatalytic performances of materials based on CS2-modified titanate nanotubes

An H., Hu X., Zhu B., Song J., Zhao W., Zhang S., Huan W.

Materials Science Poland

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2013

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Vol. 31, No. 4

531--542

EN

CS2-modified titanate nanotubes (CS2/TiO2–NTs) are fabricated by reaction of CS2 and Ti–O2Na+ species on titanate nanotubes. Pb2+ ions are coated on the modified nanotubes by ion exchange (Pb/CS2/TiO2–NTs). The products are characterized by means of nitrogen adsorption-desorption isotherms at 77 K (BET method), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), atomic absorption spectrometry (AAS), and diffuse reflectance spectroscopy (DRS). The photocatalytic performances of the products are evaluated by monitoring their catalytic activities for degradation of methyl orange under UV light irradiation. The effects of calcination temperature and atmosphere on the photocatalytic performance are investigated. The results reveal that the photocatalytic activities of CS2/TiO2–NTs and Pb/CS2/TiO2–NTs are far higher than that of primary nanotubes, and the optimum calcination temperature is 500 °C under N2 atmosphere. It is also discovered that physically adsorbed Pb2+ ions affect the photocatalytic activity of Pb/CS2/TiO2–NTs obviously. The photocatalytic activity of washed Pb/CS2/TiO2–NTs is higher than that of the unwashed one under the same thermal treatment and reaction conditions.

3

On the interpretation of the xps spectra of adsorbed layers of flotation collectors - ethyl xanthate on metallic lead

Nowak P., Laajalehto K.

Physicochemical Problems of Mineral Processing

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2007

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Vol. 41

107-116

EN

Ethyl xanthate adsorption on metallic lead was studied by X-ray photoelectron spectroscopy (XPS) after treatment of lead sample at different potentials in aqueous NaNO3 solutions containing ethyl xanthate. Continuous increase of the amount of ethyl xanthate species on the lead surface was observed as the potential was raised from - 400 mV to - 340 mV at the ethyl xanthate concentration of 10-4 M. At the potential of –400 mV and the concentration of 10-4 M the amount of xanthate at the surface was at the detection limit. Lead oxide and lead carbonate were found as the main oxidation products of metallic lead. Ethyl xanthate layer was found to decompose to sulfide like species in a few hours of excitation with monochromatic AlKa radiation, if XPS measurement was done at room temperature. Cooling the sample with liquid nitrogen down to T ≈ 130 K prevented the decomposition.

PL

Adsorpcję ksantogenianu etylowego na powierzchni metalicznego ołowiu z roztworów wodnych NaNO3 badano metodą spektrometrii fotoelektronów generowanych promieniowaniem rentgenowskim (XPS, ESCA). W roztworze ksantogenianu o stężeniu 10-4 mol dm-3, wraz ze wzrostem potencjału od wartości -400 mV do - 340 mV (względem standardowej elektrody wodorowej), ilość ksantogenianu na powierzchni wrasta od wartości znikomo małej (na pograniczu możliwości detekcji) do pokrycia wielowarstwowego. Widmo produktu sorpcji jest identyczne z widmem ksantogenianu ołowiu. We wszystkich widmach obserwowano produkty utlenienia ołowiu, produktu te zidentyfikowano jako mieszaninę węglanu i tlenku ołowiu (II), przy czym im wyższy potencjał polaryzacji próbki w roztworze ksantogenianu tym mniej produktów utlenienia obserwowano na powierzchni. Produkty te powstawały w wyniku utlenienia ołowiu w trakcie kontaktu próbki z powietrzem atmosferycznym podczas przenoszenia próbki z roztworu do spektrometru, co świadczy o tym, że powstająca warstwa produktu sorpcji ksantogenianu nie zabezpiecza powierzchni ołowiu przed utlenianiem. W wyniku naświetlania powierzchni promieniowaniem rentgenowskim w trakcie pomiaru, powstały na powierzchni ołowiu ksantogenian ołowiu rozkłada się do produktu, którego widmo jest identyczne z widmem siarczku ołowiu. Można temu zapobiec przeprowadzając pomiar w temperaturze ciekłego azotu.

4

Structures and Spectral Properties of (O-sec.-Butyldithiocarbonatio-S,S') Bis(triphenylphosphine) Copper(I) and Silver(I) Complexes

Han Q, Yang X., Lu L., Wang X.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 1

27-33

EN

New complexes (PPh3)2M(S2COR) [R = sec.-butyl,M= copper (1), silver (2)] were synthesized by the reaction of excessive triphenylphosphine and copper(II) or silver(I) xanthate, and characterized using IR, EA, 1H NMR and TG. Their crystal structures have been determined by X-ray diffraction. The light yellow crystal of the complex (1) is triclinic of space group P1, with parameters a = 10.300(2) A, b = 13.120(3) A, c = 14.570(3)A, _= 89.53(3), _ = 72.81(3), _ = 78.61(3)_, and Z = 2. The yellow crystal of the complex (2) is triclinic of space group P1, with parameters a = 10.330(2) A, b = 13.410(3) A, c = 14.420(3) A, _ = 88.61(3), _ = 73.60(3), _ = 78.93(3)_, and Z = 2. In the two complexes, the central Cu or Ag atom is in a distorted tetrahedral environment and chelated by two phosphorus atoms from the triphenylphosphine groups and two sulfur atoms from the O-alkyldithiocarbonate. IR and 1H NMR results supported the structures. The thermal analytical data indicate that the complex (1) began to decompose at 122.3_ and decomposition was complete at 370.9_, leaving Cu2S, while the complex (2) began to decompose at 133.3_ and decomposed completely at 290.3_ to Ag2S.