Production of Refiner Mechanical Pulp from Kenaf for Newsprint in Developing Countries, 1999 Pulping Conference Proceedings

Dinesh Mohta & Dibyendu N. Roy

Faculty of Forestry

University of Toronto

Phil Whiting

Trojan Technologies Inc.

Kenaf (Hibiscus cannabinus), a native of Central Africa and India, is an annual, non-wood cellulosic plant fiber. Kenaf is being promoted as a potential fiber raw material for the pulp and paper industry in view of the projected fiber supply constraints particularly in developing countries. The objective of this study is to optimize a process of refiner mechanical pulp (RMP) from kenaf for newsprint production. RMP was produced from whole kenaf (mixture of separated core and bark in 65 and 35 ratio), and whole stems of 25-38 mm length by using Sprout-Bauer 300 mm refiner. Water soaked raw material was refined to a targeted CSF of 100-125 ml by controlling three process variables of refining consistency, residence time, and refining intensity. Raw material was refined in several passes to simulate the refining actions experienced by a fiber in commercial refining. It is observed that spacing of refiner plates and number of passes are important parameters in determining the quality of pulp in a 300 mm Sprout-Bauer refiner. Results indicate that the tear and burst indices of RMP kenaf show an improvement over kenaf TMP and are comparable to that of CTMP kenaf as reported in the literature. Furnishing of RMP with kenaf chemical pulp further improved paper properties. RMP core properties have shown its limited as such use in newsprint production. Kenaf RMP has shown a good response to bleaching with hydrogen peroxide as the brightness gain per unit percentage of bleaching chemical is quite high. It can be expected that a good quality mechanical pulp from kenaf can be produced for its use in the newsprint manufacture.