Pemanfaatan lignin kraft dari lindi hitam pabrik pulp untuk pembuatan natrium lignosulfonat dan sulfonat hidroksimetil

Abstract

Black liquor kraft is a sulfuric chemical pulping byproduct. Lignin is the highest component in a black liquor approximatelly 46% from the total solid. Lignin can be isolated from kraft process black liquor by precipitation using H2SO4 20% to pH 2. The purposes of this research were to obtain and characterize kraft lignin, to find an optimum condition for sulfonation process in order to get a sodium lignosulfonate (SLS) product with appropriate characteristics as a dispersant material, to get sulfonate hydroxymethyl phenol sulfuric acid lignin (SHP-SAL), and to understand the performance of SLS and SHPSAL as dispersant agents on gypsum paste. The raw materials used in the production of SLS and SHP-SAL were obtained from sulfonated lignin which was isolated from black liquor. The SLS were made from lignin which was obtained from the sulfonation of isolated lignin in the presence of NaHSO3, also from the optimized sulfonation process of lignin using Response Surface Method (RSM) and Central Composite Design (CCD) with three factors. The SHP-SAL were made in three steps: (1) sulfuric acid lignin (SAL) was phenolated to produce phenol sulfuric acid lihnin (PSAL), (2) the hydroxymethylation of P-SAL to give hydroxymethyl phenol sulfuric acid lignin (HP-SAL), and (3) the sulfonation of HP-SAL to yield sulfonate hydroxymethyl phenol sulfuric acid lignin (SHP-SAL). The lignosulfonate compounds were identified using infrared spectrophotometer.