Quantifying the contribution of fines production during refining to the resulting paper strength

Abstract Pulp refining is an essential process step prior to paper production. The contribution of fines production during the resulting strength so far has mostly been considered qualitatively. A quantitative and experimental evaluation regarding their effect not yet published. Unbleached softwood kraft pulp was refined using a PFI mill disc refiner at different intensities. Prior handsheet forming, were removed in lab scale pressure screen from one part unrefined samples order investigate difference tensile between sheets with without fines, which furthermore produced additional wet pressing. It found, that formed 250 kWh/t are responsible for up 25% breaking length increase, while 10,000 revolutions only contribute maximum 12%. In terms efficiency, able achieve higher results compared mill, however might be attributed fibre flexibilization mill. Thus high importance development especially refiner.