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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

A novel scale-up approach for mechanical flotation 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. 877–884 Titre : A novel scale-up approach for mechanical flotation cells Type de document : texte imprimé Auteurs : J. Yianatos, Auteur ; F. Contreras, Auteur ; P. Morales, Auteur Année de publication : 2011 Article en page(s) : pp. 877–884 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  cells  Modeling  Scale-up  Simulation  Flotation  rate Résumé : Planning industrial flotation operation and earlier flotation equipment sizing are commonly based on batch flotation testing, where ideal operating conditions can be provided. Each plant has its own batch flotation standards and typically uses a time scale-up factor in order to compare laboratory and plant flotation performance. However, flotation scale-up is more complex, and it is not yet completely understood. In this work, a novel scale-up approach was developed, where the effects of the hydrodynamic regime (mixing), solid segregation (effective residence time) and froth recovery on the plant flotation rate were identified and evaluated. Each effect was then described by means of correction factors applied on the batch flotation rate, which was considered the optimal condition. These factors can be determined from laboratory and plant experimental data. This methodology was successfully applied at the rougher copper flotation plant of Codelco Norte Division, Codelco-Chile, for cells of 160 and 300 m3. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001251 [article] A novel scale-up approach for mechanical flotation cells [texte imprimé] / J. Yianatos, Auteur ; F. Contreras, Auteur ; P. Morales, Auteur . - 2011 . - pp. 877–884. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 877–884 Mots-clés : Flotation  cells  Modeling  Scale-up  Simulation  Flotation  rate Résumé : Planning industrial flotation operation and earlier flotation equipment sizing are commonly based on batch flotation testing, where ideal operating conditions can be provided. Each plant has its own batch flotation standards and typically uses a time scale-up factor in order to compare laboratory and plant flotation performance. However, flotation scale-up is more complex, and it is not yet completely understood. In this work, a novel scale-up approach was developed, where the effects of the hydrodynamic regime (mixing), solid segregation (effective residence time) and froth recovery on the plant flotation rate were identified and evaluated. Each effect was then described by means of correction factors applied on the batch flotation rate, which was considered the optimal condition. These factors can be determined from laboratory and plant experimental data. This methodology was successfully applied at the rougher copper flotation plant of Codelco Norte Division, Codelco-Chile, for cells of 160 and 300 m3. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001251