Heat treatment of paper pulp

摘要

Method of treating a chemically produced pulp suspension (2) of a material containing lignocellulose after beating (12) of said pulp suspension. The pulp suspension (2) is heated (3) in a heat treating step to a treating temperature of at least 60 DEG C, obtaining a reduced density and/or an increased porosity in a paper or paperboard product which is produced of the pulp suspension thus treated.