Optimization the soda-AQ process for cellulose pulp production and energy content of black liquor from L. leucocephala K360

A commercial variety of Leucaena leucocephala K360 was used for pulp production and papermaking employing the soda-anthraquinone process. Also, the chemical and energy contents of the resultant black liquors were determined to simultaneously optimize: pulp and paper production and energy generation. A process temperature of (185 °C), an operating time of (120 min) and an active alkali concentration of (21%) provided sheets of paper with good strength (tensile index of 12.12 N m/g, burst index of 0.38 kPa m2/g, tear index of 1.29 mN m2/g and a Kappa number of 20.5) and black liquor with a greater calorific value (14.1 MJ/kg) than that obtained with higher active alkali concentrations.However, reducing the active alkali concentration to a level in the low operation range led to less marked degradation of cellulose and allowed paper sheets with good properties to be obtained and energy to be optimally produced from the black liquor.

► The chemical composition of Leucaena leucocephala is comparable to that of other Leucaena varieties and hardwoods.
► Optimum conditions for the production of sheet papers with optimal viscosity and resistance were determined.
► Black liquor with greater calorific value was obtained at low active alkali concentration.