Preparation and characterization of carbon-enriched coal fly ash

9 pages, 8 figures, 5 tables.-- PMID: 17826888 [PubMed].-- Available online Sep 10, 2007.Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil–water. Yield in weight after sieving, unburned carbon content, and several physicochemical characteristics of the obtained fractions were used to compare the performance of the beneficiation methods. Low carbon concentration was obtained by sieving, particularly in the case of Escucha FA. However, after acid demineralization or oil agglomeration, fractions containing unburned carbon in a range of 63% to 68% were obtained. These fractions showed differences in mineral phase composition and distribution depending on the FA and on the beneficiation method used. The textural properties of the obtained fractions varied as a function of their carbon content and the beneficiation method used. However, no significant differences in morphology of the carbonaceous particles were found.The Ministry of Education and Science of Spain and European Community (FEDER) provided financial support for this work, Project No. CTM2004-04252-C02. The authors acknowledge Electric Power Stations in Lada and Escucha for supplying the FA used in this work.Peer reviewe