Method and apparatus for processing fibril cellulose and fibril cellulose product

摘要

A method for processing fibril cellulose which is in the form of aqueous fibril cellulose gel includes lowering the pH of the aqueous fibril cellulose gel to provide aqueous fibril cellulose gel of reduced water retention capacity, and dewatering the aqueous fibril cellulose gel of reduced water retention capacity to provide dewatered fibril cellulose. The dewatering is performed by pressure filtration.

主权项

1. A method for processing anionically charged fibril cellulose which is nanofibrillar cellulose derivative containing additional functional groups making the cellulose anionically charged, manufactured from wood fiber and wherein the fibrils have a maximum diameter of 50 nm and which derivative is in the form of aqueous viscoelastic fibril cellulose hydrogel, the method comprising
lowering the pH of the aqueous fibril cellulose hydrogel below the pKa value of the anionically charged fibril cellulose to pH 2-3 to provide aqueous fibril cellulose hydrogel of reduced water retention capacity, and dewatering the aqueous fibril cellulose hydrogel of reduced water retention capacity in a pressure filtration step where positive pressure is applied to the aqueous fibril cellulose hydrogel to provide dewatered fibril cellulose.