Correlations between the concentrations of P, K, and As with particle size in fly ash from power plants were examined with a viewpoint to obtain fractions suitable for forest fertilization. Fly ash samples from several CHP plants were fractionated by using four sieves and the five fractions were analyzed by ICP-OES; it was found that both P and K are concentrated in smallest size (<45 mu m) fractions. Some fly ash samples were found to contain As in excess of the legal limit of 40 mg/kg, but even in these cases it was possible to obtain size fractions that pass the legal limit while containing useful amounts of P and K. Fractionating fly ash into different sizes is identified as a viable phosphorus recovery method for obtaining legally acceptable fractions for forest fertilization. (C) 2016 Elsevier B.V. All rights reserved.