Chemical fractionation of nickel in asphaltite based bottom ash

AbstractAsphaltite, originating from petroleum, contains many kinds of mineral elements derived from its generation. These elements exist in different forms which may change throughout the asphaltite combustion process. Chemical fractionation of nickel (Ni) is necessary for risk assessment of asphaltite based bottom ash (ABBA). This study presents the concentration and fractionation of Ni in bottom ash of asphaltite (Sirnak, SE Anatolia, Turkey). Determination of total Ni in ash was performed in two stage microwave-acid digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES). Dry ashing is used for the almost complete elimination of organic materials prior to analyte determination. A seven-step sequential extraction process to fractionation of Ni from ABBA was investigated. Total Ni concentration in the ABBA was found to be 568.15 mg kg-1. The most abundant form of Ni in the ABBA was Ni as sulfide (301.23 mg kg-1). Relative abundances of the remaining Ni fractions in ABBA ...