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Effect of mechanical and chemical clay removals by hydrocyclone and dispersants on coal flotation / William J. Oats in Minerals engineering, Vol. 23 N° 5 (Avril 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 413–419 Titre : Effect of mechanical and chemical clay removals by hydrocyclone and dispersants on coal flotation Type de document : texte imprimé Auteurs : William J. Oats, Auteur ; Orhan Ozdemir, Auteur ; Anh V. Nguyen, Auteur Année de publication : 2011 Article en page(s) : pp. 413–419 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Coal  flotation  Slime  Clay  Dispersants  Hydrocyclone  Colloid  stability  DLVO  forces Résumé : Fine minerals, mostly clays, are known to have a detrimental effect on coal flotation. This paper focuses on the effect of mechanical and chemical removals of fine minerals by hydrocyclone and dispersants on coal flotation. The experimental results showed that the flotation recovery slightly increased from medium acidic to medium alkaline ranges. The flotation experiments carried out with dispersants at different dosages showed that the dispersants did not enhance the flotation recovery significantly. However, the removal of the fine fraction from the feed using a hydrocyclone significantly increased the flotation recovery. The bubble–particle attachment tests also indicated that the attachment time between an air bubble and the coal particles increased in the presence of clay particles. These attachment time results clearly showed that the clay particles adversely affected the flotation of coal particles by covering the coal surfaces which reduced the efficiency of bubble–coal attachment. An analysis based on the colloid stability theory showed that the clay coating was governed by the van der Waals attraction and that the double-layer interaction played a secondary role. It was also concluded that the best way to increase the flotation recovery in the presence of clays was to remove these fine minerals by mechanical means such as hydrocylones. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002994 [article] Effect of mechanical and chemical clay removals by hydrocyclone and dispersants on coal flotation [texte imprimé] / William J. Oats, Auteur ; Orhan Ozdemir, Auteur ; Anh V. Nguyen, Auteur . - 2011 . - pp. 413–419. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 413–419 Mots-clés : Coal  flotation  Slime  Clay  Dispersants  Hydrocyclone  Colloid  stability  DLVO  forces Résumé : Fine minerals, mostly clays, are known to have a detrimental effect on coal flotation. This paper focuses on the effect of mechanical and chemical removals of fine minerals by hydrocyclone and dispersants on coal flotation. The experimental results showed that the flotation recovery slightly increased from medium acidic to medium alkaline ranges. The flotation experiments carried out with dispersants at different dosages showed that the dispersants did not enhance the flotation recovery significantly. However, the removal of the fine fraction from the feed using a hydrocyclone significantly increased the flotation recovery. The bubble–particle attachment tests also indicated that the attachment time between an air bubble and the coal particles increased in the presence of clay particles. These attachment time results clearly showed that the clay particles adversely affected the flotation of coal particles by covering the coal surfaces which reduced the efficiency of bubble–coal attachment. An analysis based on the colloid stability theory showed that the clay coating was governed by the van der Waals attraction and that the double-layer interaction played a secondary role. It was also concluded that the best way to increase the flotation recovery in the presence of clays was to remove these fine minerals by mechanical means such as hydrocylones. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509002994