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Estimation of the actual bubble surface area flux in flotation / J. Leiva in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 888–894 Titre : Estimation of the actual bubble surface area flux in flotation Type de document : texte imprimé Auteurs : J. Leiva, Auteur ; L. Vinnett, Auteur ; F. Contreras, Auteur Année de publication : 2011 Article en page(s) : pp. 888–894 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Flotation  bubbles  Flotation  frothers  Sampling  Modeling Résumé : The bubble surface area flux, SB, defined as the ration between the superficial gas rate JG and the Sauter mean bubble diameter D32, has been widely used to describe the gas phase dispersion efficiency in flotation machines, and from this predict flotation performance, notable mineral recovery to forecast plant economics. In this work, results of bubble size distribution (BSD) generated in a pilot column are analyzed. Using video and image analysis techniques, the impact of different sampling rates on the BSD was evaluated. Measurements were carried out for D32 = 1–2 mm, JG = 0.5–1.5 cm/s and two frother concentration, with a maximum sampling rate of 100 fps. In addition, the bubble rise velocity in the bubble swarm was measured, as a function of the individual bubble diameter, for different operational conditions. The identification of the BSD depends on the proper selection of the visual field and sampling rate for acquisition and processing of bubble images. Distortion in the estimation occurs because a larger holdup of small bubbles is observed, relative to the overall data set, due to their lower velocity. The actual BSD was obtained by correcting the observed population, considering the effect of bubble rise velocity. Thus, the actual bubble surface area flux, SB, was calculated. The results were evaluated at a pilot scale (air–water system) as well as an industrial plant scale (air-pulp system). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000257 [article] Estimation of the actual bubble surface area flux in flotation [texte imprimé] / J. Leiva, Auteur ; L. Vinnett, Auteur ; F. Contreras, Auteur . - 2011 . - pp. 888–894. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 888–894 Mots-clés : Froth  flotation  Flotation  bubbles  Flotation  frothers  Sampling  Modeling Résumé : The bubble surface area flux, SB, defined as the ration between the superficial gas rate JG and the Sauter mean bubble diameter D32, has been widely used to describe the gas phase dispersion efficiency in flotation machines, and from this predict flotation performance, notable mineral recovery to forecast plant economics. In this work, results of bubble size distribution (BSD) generated in a pilot column are analyzed. Using video and image analysis techniques, the impact of different sampling rates on the BSD was evaluated. Measurements were carried out for D32 = 1–2 mm, JG = 0.5–1.5 cm/s and two frother concentration, with a maximum sampling rate of 100 fps. In addition, the bubble rise velocity in the bubble swarm was measured, as a function of the individual bubble diameter, for different operational conditions. The identification of the BSD depends on the proper selection of the visual field and sampling rate for acquisition and processing of bubble images. Distortion in the estimation occurs because a larger holdup of small bubbles is observed, relative to the overall data set, due to their lower velocity. The actual BSD was obtained by correcting the observed population, considering the effect of bubble rise velocity. Thus, the actual bubble surface area flux, SB, was calculated. The results were evaluated at a pilot scale (air–water system) as well as an industrial plant scale (air-pulp system). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000257

Flotation rate distribution in the collection zone of industrial cells / J. Yianatos in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1030–1035 Titre : Flotation rate distribution in the collection zone of industrial cells Type de document : texte imprimé Auteurs : J. Yianatos, Auteur ; L. Bergh, Auteur ; L. Vinnett, Auteur Année de publication : 2011 Article en page(s) : pp. 1030–1035 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  Flotation  rate  distribution  Industrial  cells  Radioactive  tracer Résumé : The batch flotation process has been commonly characterized assuming a flotation rate distribution function F(k), e.g.: Dirac delta, Rectangular, Gamma or Weibull functions. The identification of F(k) for the collection zone of continuous industrial cells is more complex and to the authors knowledge, has not been reported yet. In this work, a novel procedure to estimate the flotation rate distribution from the collection zone of industrial flotation cells, using the radioactive tracer technique, is presented. The approach consists of measuring the impulse response of the floatable mineral tracer concentration, and non-floatable gangue tracer concentration (Residence Time Distribution, RTD), in the cell tailings. Then, the floatable tracer concentration can be compared with the model prediction, using the Gamma function and the RTD of the non-floatable tracer. Thus, the F(k) distribution parameters were obtained by means of the least-square estimation. The new approach was successfully tested in industrial rougher flotation cells of large size. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000141X [article] Flotation rate distribution in the collection zone of industrial cells [texte imprimé] / J. Yianatos, Auteur ; L. Bergh, Auteur ; L. Vinnett, Auteur . - 2011 . - pp. 1030–1035. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 1030–1035 Mots-clés : Flotation  Flotation  rate  distribution  Industrial  cells  Radioactive  tracer Résumé : The batch flotation process has been commonly characterized assuming a flotation rate distribution function F(k), e.g.: Dirac delta, Rectangular, Gamma or Weibull functions. The identification of F(k) for the collection zone of continuous industrial cells is more complex and to the authors knowledge, has not been reported yet. In this work, a novel procedure to estimate the flotation rate distribution from the collection zone of industrial flotation cells, using the radioactive tracer technique, is presented. The approach consists of measuring the impulse response of the floatable mineral tracer concentration, and non-floatable gangue tracer concentration (Residence Time Distribution, RTD), in the cell tailings. Then, the floatable tracer concentration can be compared with the model prediction, using the Gamma function and the RTD of the non-floatable tracer. Thus, the F(k) distribution parameters were obtained by means of the least-square estimation. The new approach was successfully tested in industrial rougher flotation cells of large size. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000141X