GB501485A - A process for the production of a pure white cellulose product from raw sawdust - Google Patents

Abstract

501,485. Obtaining cellulosic fibres. RUZICKA, C., and SALE, C. V., and SALE, G. S., (trading as SALE & CO.). April 13, 1938, Nos. 11307 and 17157. [Class 2 (ii)] Fibrous cellulosic materials such as wood, sawdust, shavings, esparto grass, jute, hemp, flax, linseed-straw, coconut fibre, bamboo, or soya bean stalks, are subjected to treatment in a solution of alkaline reaction, e.g. caustic potash or sodium carbonate solution, at a temperature below the boiling point of the solution. The strength of the solution and period of immersion are selected so as to effect a partial separation of the fibres and removal of resins, waxes, and other binding agents without injury to the fibres. The partially separated fibres are washed and then immersed in a dilute solution of sulphurous acid to complete separation of the fibres by removal of all remaining resins, waxes, and other binding agents, the solution being maintained at a temperature below its boiling point. The fibres are washed and then subjected to the action of an oxidizing agent so as to remove colouring matter. Preferably, the alkaline solution and the sulphurous acid solution are used hot, e.g. at a temperature of 90-95‹ C. The oxidizing agent may be sodium hypochlorite solution. Sodium carbonate of 7¢ per cent or caustic potash of 3 per cent concentration may be used for the first treatment. The separated fibres may be used for spinning.