International Journal of Geology, Earth & Environmental Sciences ISSN: 2277-2081 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jgee.htm 2014 Vol. 4 (2) May-August, pp. 51-61/Nfissi et al. Research Article © Copyright 2014 | Centre for Info Bio Technology (CIBTech) 51 EVALUATION OF THE CAPACITY OF CEMENT KILN DUST AND FLY ASH FOR THE NEUTRALIZATION OF ACIDIC MINE TAILINGS *S. Nfissi 1 , S. Alikouss 1 , Y. Zerhouni 1 , R. Hakkou 2 , M. Benzaazoua 3,4 , M. Samir 1 and Z. Baroudi 1 1 Laboratory of Applied Geology, Geomatics and Environment, Department of Geology, Faculty of Science Ben MSik. Cdt Driss El Harti Avenue, P.O. 7955 Sidi Othman, Casablanca, Morocco 2 Laboratory of Chemistry of the Materials and Environment, Faculty of Science and Technology Guéliz, Cadi Ayyad University, Abdelkarim Elkhattabi Avenue, Gueliz, P.O. Box 549, Marrakech, Morocco 3 National Institute of Applied Science of Lyon, Laboratory of Civil and Environmental Engineering, Sadi Carnot Build, 9, a physique street, 69621 Villeurbanne cedex, France 4 IDRC Research Chair in Management and Stabilization of Mining and Industrial Wastes, University of Quebec Abitibi Témiscamingue, 445 Boul. University, Rouyn-Noranda, QC J9X 5E4, Canada *Author for Correspondence ABSTRACT The production of acid mine drainage (AMD) is considered as a serious problem for the mining industry. The oxidation of sulphide minerals causes the production of sulfuric acid resulting in a decrease in pH. This decrease causes the mobilization of metals; these very high concentrations may be a threat to the receiving environment. Abandoned Kettara Mine (Central Jebilet, Morocco), that has been chosen as a pilot site contains 3Mt of the residues that generate acidic leachates with a pH between 2.9 and 1.5 (Nfissi et al., 2011). The acidification potential (AP) of that is between 51 and 453kg CaCO 3 /t while that the net of neutralization potential (NNP) ranges from -453 to -22.5 Kg CaCO 3 /t (Hakkou et al., 2008a). In order to control the AMD in this mine, we opted a protocol based on the use of cement kiln dust (CKD) from the Lafarge cement of Bouskoura (Region of Casablanca) and fly ashes (FA) of the thermal power plant of Jorf Lasfar at El Jadida city (Coastal city 90km south-west from Casablanca). The main objective of this study is to enhance the value of these industrial by-products considered as wastes for rehabilitation of mine sites. A mineralogical and physico-chemical characterization of these materials has been done and supplied promising results as to their effectiveness in stabilizing tailings. Indeed, these are highly alkaline with a high net neutralizing capacity which is in the order of 900.63 kg CaCO 3 /t CKD and 243.75 kg CaCO 3 /t for FA. CKD and FA have a high neutralization potential and would constitute the main component of amendment alkali and/or covering that may reduce greatly the effects of DMA in this semi-arid climate mine and in other similar sites. Keywords: Kettara, AMD, CKD, FA, Characterization, Alkali Amendment, Recovery INTRODUCTION Morocco knows an intense mining activity which represents 6% of gross domestic product (GDP) in 2010 (Memee, 2011), however, there are over two hundred closed sites are not rehabilitated. During activity and after mine closure, the places of tailing storage (waste rock piles and parks tailing concentrator) can cause the production of acid mine drainage with potentially harmful consequences on the environment. This phenomenon causes the mobilization (dissolution) of heavy metals and other toxic substances that may pollute water resources and destroy natural ecosystems (Collon, 2003). The DMA results from the oxidation of inorganic sulfur acidogens (such as pyrite, pyrrhotite, chalcopyrite...) in contact with atmospheric oxygen and water (Kleinmann et al., 1981; Sracek et al,. 2004). Contaminated water by the DMA can come from various types of exploitation, including mines of precious metals (Au, Ag...), based metals (Cu, Ni, Zn, Pb...), coal and uranium (Plante, 2004). AMD triggers when minerals acidivores with neutralizing effects are expired.