Pulping Of Vetiver Grass With NH4OH-KOH-AQ Mixtures

Abstract

The aim of this work was to study the effects of various experimental parameters on vetiver grass (Vetiveria nemoralis A. Camus) pulping. Mixtures of NH₄OH-KOH were used as cooking liquors. The caustic potash did not only reduce the NH₃ usage and cooking time, but also provided a potassium source as a fertilizer in the black liquor. Anthraquinone (AQ) was added in certain amount as cooking catalyst. The experiment was conducted following a central composite design involving three pulping variables (amount of KOH: 3.5 to 7% on oven-dried sample, amount of NH₄OH : 25 to 45% on oven-dried sample, and cooking temperature : 145 to 160°C). The quantity of anthraquinone was fixed at 0.1% on oven-dried sample. Pulping time was fixed at 2 hours and liquid-to-oven-dried sample ratio was 8:1. Responses of pulp properties to the process variables were analyzed using DESIGN-EXPERT^®, a computer-aided design of experiment software. The pulp properties revealed that this pulp is capable for making of printing and writing paper. Furthermore, this study provided a new pulping process for vetiver grass to reduce problems of discharge black liquor.