Fig. (5) Concentrations of As vs. CaO and Fe₂O₃ in each particle-size fraction of BA studied. The fractions were numbered in the order of decreasing particle size: (1) >2 mm, (2) 1-2 mm, (3) 0.6-1.0 mm, (4) 0.5-0.6 mm, (5) 0.4-0.5 mm, (6) 0.2-0.4 mm, (7) 0.1-0.2 mm, (8) 0.08-0.1 mm and (9) <0.08 mm.