GB277163A - A process and apparatus for extracting the pure cellulose from the bagasse of sugar cane - Google Patents

Abstract

277,163. Valet, E. C. H. Aug. 25, 1926. Pulp, preparation of; preliminary treatment of materials.-Pure cellulose for paper-making is extracted from the bagasse of sugar cane by first agitating it with a heated solution of 3-5 per cent lime and subsequently boiling under pressure in a solution of about 6 per cent caustic soda combined with a solution of 2-3 per cent sodium sulphate or hyposulphite until all foreign matter is dissolved. The bagasse may be subjected to a cutting up process before and after the treatment with lime, and to cleaning with steam and bleaching after the boiling with caustic soda. The proportions used may be to every 100 pounds of dry bagasse 18 gallons of caustic soda solution and 12 gallons sodium sulphite or hyposulphite solution : to this solution may be added 12 gallons of 3 per cent lime solution. A weak solution of calcium sulphite mav also be added to the caustic soda solution. The boiling step is carried out in a digester comprising a counterpoised cover 2 operated from a handwheel 5, and resting on a movable perforated inner cover 3 which rests on the bagasse and carries a depending pipe 10 through which the liquid is carried by steam entering at the bottom of the digester through a perforated hood 11 and passing upwards through a pipe 8, the liquid passing back through the perforated cover and re-entering the pipe 8 through a perforated conical member 9.