Papermaking potential of Citrus sinensis trimmings using organosolv pulping, chlorine-free bleaching and refining

This work aims to show the suitability of ethanolamine cooking when applied to orange tree trimmings, and to study the effect of peroxide bleaching and refining on some key properties. As for bleaching, we used a design of experiments to discuss the influence of peroxide concentration, time and temperature on the yield, brightness, viscosity, kappa number of pulps and mechanical properties of paper sheets. Refining was studied by analysing the diminishment in freeness and the mechanical properties of paper sheets formed. Results showed that even a mild bleaching process gives out a high relative brightness gain, but a multiple-step process is necessary to achieve enough brightness for printing paper. Mechanical properties of non-refined pulps were found to be too low for paper of any grade, but they were greatly improved by refining.