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Application of coal fly ash to circumneutral mine waters for the removal of sulphates as gypsum and ettringite / Godfrey Madzivire in Minerals engineering, Vol. 23 N° 3 (Fevrier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 3 (Fevrier 2010) . - pp. 252–257 Titre : Application of coal fly ash to circumneutral mine waters for the removal of sulphates as gypsum and ettringite Type de document : texte imprimé Auteurs : Godfrey Madzivire, Auteur ; Leslie F. Petrik, Auteur ; Wilson M. Gitari, Auteur Année de publication : 2011 Article en page(s) : pp. 252–257 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Fly  ash  Acid  mine  drainage  Circumneutral  mine  water  Sulphates  Neutralization Résumé : South African power stations generate large amounts of highly alkaline fly ash (FA). This waste product has a serious impact on the environment. Acid mine drainage (AMD) is another environmental problem associated with mining. AMD has high heavy metal content in addition to high sulphate concentrations. Several studies have shown that 80–90% of sulphates can be removed when FA is co-disposed with AMD rich in Fe and Al. In South Africa, sources of contaminated mine waters, unlike AMD have circumneutral pH and much lower concentrations of Fe and Al, but rich in Ca and Mg. Treatment of such waters with FA resulted in no significant removal of sulphates when treated to pH less than 10. Subsequent treatment of circumneutral mine water to pH greater than 11 resulted in more than 60% sulphate removal. Treatment of circumneutral mine water to pH greater than 11 with FA followed by seeding with gypsum crystals and the addition of amorphous Al(OH)3 resulted in removal of sulphate to levels below the Department of Water Affairs and Forestry (DWAF) water quality effluent limit (500 ppm). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900301X [article] Application of coal fly ash to circumneutral mine waters for the removal of sulphates as gypsum and ettringite [texte imprimé] / Godfrey Madzivire, Auteur ; Leslie F. Petrik, Auteur ; Wilson M. Gitari, Auteur . - 2011 . - pp. 252–257. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 3 (Fevrier 2010) . - pp. 252–257 Mots-clés : Fly  ash  Acid  mine  drainage  Circumneutral  mine  water  Sulphates  Neutralization Résumé : South African power stations generate large amounts of highly alkaline fly ash (FA). This waste product has a serious impact on the environment. Acid mine drainage (AMD) is another environmental problem associated with mining. AMD has high heavy metal content in addition to high sulphate concentrations. Several studies have shown that 80–90% of sulphates can be removed when FA is co-disposed with AMD rich in Fe and Al. In South Africa, sources of contaminated mine waters, unlike AMD have circumneutral pH and much lower concentrations of Fe and Al, but rich in Ca and Mg. Treatment of such waters with FA resulted in no significant removal of sulphates when treated to pH less than 10. Subsequent treatment of circumneutral mine water to pH greater than 11 resulted in more than 60% sulphate removal. Treatment of circumneutral mine water to pH greater than 11 with FA followed by seeding with gypsum crystals and the addition of amorphous Al(OH)3 resulted in removal of sulphate to levels below the Department of Water Affairs and Forestry (DWAF) water quality effluent limit (500 ppm). DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900301X