Milox pulping of EFB was used to obtain pulps. In the first Milox stage, the influences of operating variables on pulp properties were studied and polynomial and neural fuzzy models that reproduced the experimental results with errors less than 10% were developed. Operating variables were found (93 wt.% of formic acid, 3 wt.% of hydrogen peroxide, and 165 min) that yielded acceptable pulp properties (40.5% yield, 50.3% brightness and 608 mL/g viscosity) at reasonable chemical and energy costs. The second stage was studied by subjecting the liquors of the previously optimized first stage to different treatment times. This time should be 30 min or less, to avoid a negative effect on viscosity. The residual liquor from the first Milox stage contained virtually no precipitable lignin and only low amounts of sugar (wt.%): glucose 0.71, xylose 4.22, galactose 1.19, mannose 0.22, all on original raw material dry. (C) 2011 Elsevier Ltd. All rights reserved.