A sample of 100 g (oven-dried basis) of hemp bast fibres was placed in a polyethylene bag and then the following was added sequentially: 0.1% MgSO4 (in the form of an aqueous solution), 1% sodium hydroxide solution and distilled water in an amount ensuring the 10% concentration of fibrous slurry desired. The contents of the bag were then mixed by squeezing and placed in the Jayme reactor. The autoclave was closed, filled with oxygen and heated to a maximum temperature of 100 °C for 30 minutes, at which temperature it remained for a further 60 minutes. After 60 minutes of delignification, the pressure was released, the reactor opened and the pulp discharged, filtered and washed with four aliquots of 1000 ml deionised water and stored in a plastic bag for further treatment.