High Yield Pulps from <I>Sesbania</I> Species

Abstract

Cold soda pulps were prepared from Sesbania aculeata and Sesbania aegyptiaca (with bark) under identical conditions. The chips Were soaked in a solution of caustic soda of different concentrations (11.25 gpl.-22.5 gpl.) for a period of 4 hours keeping the chips to liquor ratio 1 : 4. The softened chips were refined twice in Sprout Waldron refiner at about 10% consistency and keeping tbe clearance between plates 250 and 125 microns respectively. Temperature during refining was kept about 50°C. The pulps were screened on vibratory screen having 0.25 mm slots. The unbleached yield of screened pulps was determined in the range of 70.62-78.9% in case of Sesbania aculea, a and 70.50-76.29% in case of Sesbania aegypliaca. The pulps were beaten in lampen mill varying the beating time, to obtain different freeness. The pulps were classified. using Bauer Mc.-Nett classifier. The fines passing tbrougb 200 mesb wne 15.01-31.63% and 14.41-34.8% in Sesbania aculeala and Sesbania argyptiaca respectively. This is comparable with the hardwood chemi-mechanical pulps. Tbe opacity and brightness of unbleached pulps were 96.9% and 54.5% in case of S. aculeata and 97.1% and 565% in case of Sesbania aegyptiaca respectively. The cold soda pulps obtained from the above two species, can be admixed with long fibre chemical pulps to produce newsprint. The pulps are also suitable when admixed long fibre pulp for the production of several industrial papers.