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    Wyświetlanie 1-8 z 8
    Tytuł:
    The effect of polyacrylic acid on the surface properties of calcite and fluorite aiming at their selective flotation
    Autorzy:
    Zhang, C.
    Gao, Z.
    Hu, Y.
    Sun, W.
    Tang, H.
    Yin, Z.
    He, J.
    Guan, Q.
    Zhu, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/110577.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    calcite
    fluorite
    selective flotation
    polyacrylic acid
    Opis:
    In this study, the polyacrylic acid (PAA) was studied as a selective depressant for calcite in the selective flotation of fluorite and calcite, and the implications of this process for the separation of fluorite ore were studied using micro-flotation tests, and the results were analyzed with Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The flotation tests indicated that the preferential adsorption of PAA onto calcite rather than sodium oleate (NaOl) could selectively depress the flotation of calcite, allowing its separation from fluorite at pH 7. The zeta potential of calcite became more negative with the addition of PAA rather than with NaOl. However, the characteristic features of PAA adsorption were not observed for fluorite, suggesting that NaOl preferentially adsorbed on the surface of fluorite, or that PAA could be replaced by NaOl on the fluorite surface. FT-IR and XPS analysis were utilized to obtain a better understanding of the mechanism by which PAA was more strongly adsorbed on the calcite surface than NaOl. This was revealed to occur through chemical bonding between the carboxyl group of PAA and the hydroxyl groups of the Ca species on the calcite surface, modifying the structure of the adsorbed layer. A possible adsorption mechanism, along with a postulated adsorption mode for the surface interaction between PAA and calcite, is proposed.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 3; 868-877
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Selective flotation of witherite from calcite using potassium chromate as a depressant
    Autorzy:
    Qiu, Yangshuai
    Zhang, Lingyan
    Jiao, Xuan
    Guan, Junfang
    Li, Ye
    Qian, Yupeng
    Powiązania:
    https://bibliotekanauki.pl/articles/110784.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    witherite
    calcite
    selective flotation
    sodium oleate
    potassium chromate
    Opis:
    Witherite has been widely used as an industrial and environmental source of barium, with calcite being the primary associated carbonate mineral. However, few studies have been conducted to effectively concentrate witherite from barium ores. In this work, with the treatment of potassium chromate (K2CrO4) and sodium oleate (NaOL), witherite was selectively separated from calcite through selective flotation at different pH conditions. In addition, contact angle, Zeta potential, adsorption and X-ray photoelectron spectroscopy measurements were performed to characterize the separation mechanisms. The results demonstrated that NaOL had a strong collecting ability for both witherite and calcite; nevertheless, witherite could be effectively selected from calcite with the highest recovery at pH 9 in the presence of K2CrO4. From the XPS measurements, NaOL and K2CrO4 were found to be primarily attached to the surfaces of witherite and calcite through chemisorption. The presence of K2CrO4 on the surface of calcite adversely influenced the NaOL adsorption, which could make the flotation separation efficient and successful.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 2; 565-574
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Probable mechanism of the operation of the flotation pulp density on the selective flotation of the sulphide minerals
    Wpływ zagęszczania operacji mętów flotacyjnych na flotację selektywną minerałów siarczkowych
    Autorzy:
    Petrova, H.
    Boteva, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/349563.pdf
    Data publikacji:
    2006
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    materiały siarczkowe
    flotacja selektywna
    gęstość mętów
    sulphide minerals
    selective flotation
    pulp density
    Opis:
    In this report it's looked through the problem about the research of the possibilities, by the change of the solid phase content in the pulp for improvement of the flotation process selectivity during the flotation of the multicomponent ores. It's searched for the relation between the lessened aeration in the conditions of the flotation with higher density of the flotation pulp and the competitive struggle between the main sulphide minerals which differ theirselves of it's hydrophobic mineral surface and of the processes, running in the three-phased froth as well. The results of the research indicate that the increased density doesn't always lead to the decrease of the process of selectivity. It's found that the rising of the solid phase content in the pulp up to a definite limit improves the selectivity of the process, but it can hardly get worse above this limit. The limit is most likely to be different for the different technological cases, but it's obviously to be always available.
    Artykuł ten przedstawia problem badania możliwości, poprzez zmianę zawartości fazy stałej w mętach, poprawy selektywności procesu flotacji podczas flotacji wieloskładnikowych rud. Poszukiwano relacji pomiędzy zmniejszeniem aeracji w warunkach flotacji większej gęstości mętów flotacyjnych, różnicowanie pomiędzy głównymi minerałami siarczkowymi, co do ich hydrofobowości powierzchni oraz procesami przeprowadzanymi w trójfazowej pianie. Wyniki badań wskazują, że zwiększana gęstość nie zawsze prowadzi do obniżenia selektywności procesu. Stwierdzono, że zwiększenie fazy stałej w mętach do pewnej granicy zwiększa selektywność procesu, a może ją pogorszyć powyżej tej granicy. Granica zazwyczaj jest różna dla różnych przypadków technologicznych, ale jest zawsze możliwa do określenia.
    Źródło:
    Górnictwo i Geoinżynieria; 2006, 30, 3/1; 295-299
    1732-6702
    Pojawia się w:
    Górnictwo i Geoinżynieria
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flotation separation of scheelite from calcite using sodium polyacrylate as depressant
    Autorzy:
    Zhang, Y.
    Chen, R.
    Li, Y.
    Wang, Y.
    Luo, X.
    Powiązania:
    https://bibliotekanauki.pl/articles/110896.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    scheelite
    calcite
    flotation
    sodium polyacrylate
    selective depression
    Opis:
    The depressing properties of sodium polyacrylate (PA-Na) for calcite from scheelite were studied by microflotation experiments, zeta potentials, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation. Flotation results revealed that the selective depression effect of PA-Na was better than that of sodium silicate (Na2SiO3), and PA-Na can depress calcite more effectively than scheelite. The flotation recovery of scheelite and calcite kept at about 75% and 15% respectively at the pulp pH 9.3~9.6 and PA-Na concentration from 37.5 mg/dm3 to 50 mg/dm3. The zeta potentials of the minerals were significantly altered and the zeta potential of calcite became more negative than scheelite. XPS analysis deduced the occurrence of chemisorption between PA-Na and mineral surfaces, and the chemisorption of PA-Na on calcite was stronger than on scheelite. The results from DFT calculation demonstrated that the absolute value of the adsorption energy in the presence of PA-Na on the surface of calcite {104} was larger than on the surface of scheelite {111}. With the combination of the analysis, it could be concluded that calcite was more easily depressed than scheelite, and this finding remarkably matched with the microflotation experimental results. Furthermore, by using PA-Na as depressant, the flotation separation of scheelite from calcite can be achieved by controlling the flotation pH and PA-Na dosage.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 2; 505-516
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reverse flotation of collophanite at natural pH using isooctyl polyoxyethylene ether phosphate as a collector
    Autorzy:
    Li, Hongqiang
    Zhang, Wen
    Chen, Qian
    Huang, Peng
    Kasomo, Richard M.
    Zou, Ze
    Weng, Xiaoqing
    He, Dongsheng
    Yang, Siyuan
    Song, Shaoxian
    Powiązania:
    https://bibliotekanauki.pl/articles/1445877.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    reverse flotation
    dolomite
    fluorapatite
    AEP
    selective adsorption
    Opis:
    Reverse flotation of collophanite at natural pH could significantly decrease the cost of pH regulators. In this study, isooctyl polyoxyethylene ether phosphate (AEP) was tested as a new surfactant in the reverse flotation of collophanite. Micro-flotation tests were conducted, and the adsorption mechanism of the new collector was analysed using X-ray photoelectron spectroscopy (XPS) and zeta potential analyses. The results of the flotation tests demonstrated that AEP could enable dolomite to float under natural pH (pH=7.2) and showed profound selectivity towards dolomite as opposed to fluorapatite. Based on the zeta potential and XPS results, the adsorption phenomena are mainly attributed to calcium active sites on both mineral surfaces. Dolomite possesses more magnesium active sites than fluorapatite, which tend to reinforce the interaction effect between AEP and dolomite. Furthermore, when compared to CO32- ions on the dolomite surface, PO43- ions on the fluorapatite surface tend to exhibit a stronger hindrance to the adsorption of AEP on the fluorapatite surface. This is attributed to their larger volumes and more charges on their surfaces, thereby causing a floatability difference between the two minerals.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 4; 78-86
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flotation separation of enargite from complex copper concentrates by selective surface oxidation
    Autorzy:
    Li, Tangfei
    Zhang, Yansheng
    Zhang, Bo
    Jiao, Fen
    Qin, Wenqing
    Powiązania:
    https://bibliotekanauki.pl/articles/110698.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    mineralogy
    enargite
    selective surface oxidation
    froth flotation
    EDTA extraction
    Opis:
    In previous study, the promising results of separating enargite from non-arsenic copper sulfides were obtained using selective surface oxidation in pure mineral systems. However, this technology was not well understood in real ores or concentrates. In this study, the flotation separation of enargite from complex copper concentrates by selective surface oxidation was investigated. The effects of regrinding, pulp pH, NaClO concentration, conditioning time and flotation time on separation of enargite from NECu minerals were studied. The mineralogical characteristics of the flotation feed and products were showed as an instructive tool to understand the separation results. According to the results of EDTA extraction, the possible mechanism for separation of enargite from NECu minerals is that enargite is more resistant to oxidized compared to NECu minerals. The following order for the oxidation of NECu minerals and enargite is obtained: chalcopyrite (chalcocite, digenite)> enargite (covellite).
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 4; 852-864
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Adsorption Characteristics of Combined Sulfhydryl Collector on Chalcopyrite and Arsenopyrite in Flotation of Complex Gold Ores
    Charakterystyka adsorpcji kombinowanego kolektora sulfhydrylowego na chalkopirycie i arsenopirycie w flotacji złożonych rud złota
    Autorzy:
    Matveeva, Tamara
    Gromova, Nadezhda
    Powiązania:
    https://bibliotekanauki.pl/articles/318729.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Przeróbki Kopalin
    Tematy:
    flotacja
    selektywny kolektor
    rudy złota
    flotation
    selective collector
    gold ores
    Opis:
    The paper presents the results of experimental study of the adsorption properties of the combined sulfhydril collecting reagent – a mixed solution of sodium diethyl-dithiocarbamate (DEDTC) and oxypropyl diethyl-dithiocarbamate ester (OPDTC) towards chalcopyrite and arsenopyrite with a view to its application as a selective collector of Au-containing sulfide minerals in flotation of complex refractory ores. Combined diethyl-dithiocarbamate solution (DEDTCc) incorporated a fixed content of anionic and non-ionic components (DEDTC:OPDTC = 1:1) and occurred variable hydrophobic effect on the surface of the basic gold-bearing sulfide minerals – chalcopyrite and arsenopyrite. The mechanism of adsorption of the components of combined collector on the surface of chalcopyrite and arsenopyrite was identified to form characteristic molecular shape of adsorbed collector convex neoplasms and sinter chemically adsorbed film of the reactant, which is firmly anchored on the surface. The newly formed phase of the adsorbed reagent did not dissolve in water at a subsequent washing. In this case, the phase of nonionic ester OPDTC was partially removed by water and the residual adsorbed droplets changed their shape and became flatter. By X-ray microanalysis C and O bands relating to the structure of the combined DEDTCc were identified on the surface of arsenopyrite and chalcopyrite. The original technic for analyzing the liner dimension of surface images with an application of scanning laser microscopy and the software of the Analyzer was developed and the authors succeeded to provide a quantitative evaluation of the adsorption of DEDTCc on the surface of chalcopyrite and arsenopyrite.
    W pracy przedstawiono wyniki badań eksperymentalnych właściwości adsorpcyjnych kombinowanego odczynnika zbierającego sulfhydryl – mieszanego roztworu dietyloditiokarbaminianu sodu (DEDTC) i estru oksypropylodietyloditiokarbaminianowego (OPDTC) w kierunku chalkopirytu i arsenopirytu w celu jego zastosowania selektywny kolektor minerałów siarczkowych zawie- rających Au w flotacji złożonych rud ogniotrwałych. Połączony roztwór dietylo-ditiokarbaminianu (DEDTCc) zawierał stałą zawartość składników anionowych i niejonowych (DEDTC: OPDTC = 1: 1) i zaobserwowano zmienny efekt hydrofobowy na powierzchni podstawowych minerałów siarczkowych niosących złoto - chalkopirytu i arsenopirytu. Mechanizm adsorpcji składników kombinowanego kolektora na powierzchni chalkopirytu i arsenopirytu został zidentyfikowany jako charakterystyczny skład molekularny adsorbowanego kolektora chemicznie zaadsorbowanych cząsteczek reagenta, który jest mocno zakotwiczony na powierzchni. Nowo utworzona faza zaadsorbowanego odczynnika nie rozpuszczała się w wodzie podczas kolejnego płukania. W tym przypadku faza niejonowego estru OPDTC została częściowo usunięta przez wodę, a resztkowe zaadsorbowane kropelki zmieniły swój kształt i stały się bardziej płaskie. Za pomocą mikroanalizy rentgenowskiej zidentyfikowano pasma C i O dotyczące struktury połączonego DEDTCc na powierzchni arsenopirytu i chalkopirytu. Opracowano oryginalną technikę analizy wymiaru liniowego obrazów powierzchni za pomocą skaningowej mikroskopii laserowej i oprogramowania analizatora, a autorom udało się określić ilościową ocenę adsorpcji DEDTCc na powierzchni chalkopirytu i arsenopirytu.
    Źródło:
    Inżynieria Mineralna; 2019, 21, 1; 153-157
    1640-4920
    Pojawia się w:
    Inżynieria Mineralna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of flotation reagents by normalization procedures
    Autorzy:
    Drzymala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/109804.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    flotation
    separation
    foam
    froth
    frother
    selectivity
    efficiency
    normalization
    generic reagents
    selective reagents
    internal parameter
    external parameter
    Opis:
    Froth flotation is a dynamic multiphase process in which particulate matter is separated with the help of chemical reagents by gas bubbles immersed in water. The original flotation results are usually presented in the form of kinetic curves relating recovered particulate matter mass (yield ) or mass of a selected component (recovery ), both shortly denoted as y, versus process time t at different concentrations c (g/dm3) of the applied reagents. The kinetic curves can be modified into three: incentive (maximum yield or recovery ymax vs c), limits (ymax vs kinetic constant k or specific rate) and half-life of flotation (t1/2 vs c) curves. The original and modified curves can be normalized by taking into account either an external parameter such as molecular mass (MW), critical coalesce concentration (CCC), critical concentration at the minimum bubble velocity (CMV), dynamic foaming index (DFI), and many other parameters or an internal parameter such as time, concentration needed to achieve certain yield, recovery (y) or kinetic constant. Normalization leads to new flotation curves and provides additional useful information about flotation performance. Normalization can be fully effective, partial or ineffective. Normalization of the original flotation kinetic curves usually is ineffective. Also, normalization of the incentive curve with external parameters such as frother molecular mass, which changes reagent concentration from c (g/dm3) to C (mol/dm3), is also ineffective. Partially effective are normalizations with other external parameters such as CCC and CMV, usually within the same class of regents, for instance alcohols. Only DFI seems to be a universal external normalization parameter for flotation results because it provides fully effective normalization and thus predicts the flotation results. Limited data on DFI restrict a full verification of this hypothesis. Normalization of the modified flotation curves with internal parameters such as k50 (value of 1st order kinetic constant when recovery or yield is 50% after a given flotation time), Ct1/2 (frother concentration in mol/dm3 at which the flotation half-life has an arbitrarily chosen value) and cy75 (frother concentration in g/dm3 at which recovery or yield is 75% after a given flotation time) is a good base for practical classification of flotation reagents.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 1; 182-192
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-8 z 8

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