Thermal treatment of the precipitated solid material (PSM) from the waste black liquor (WBL)

Precipitated solid materials (PSM) from waste black liquor (WBL), at pH 8.5 -9.0, produced from cooking of rice straw in paper mill factories were ther mally treated. The cooking process led to decrease in organic material and partial substitution in silica structure. During this cooking process, thre e probable stages of mass loss comprise removal of moisture, volatile relea se, and combustion. The chemical analysis depicts the cooking effect on leaching either the hig h percentage elements (Ca, Na, and K) or some metallic cations (Mn, Cd, Zn and Cu) in the parent rice straw. Silica hydrate, amorphous silica and crys talline silica were obtained at < 600 degrees C, 600-700 degrees C and at > 800 degrees C, respectively. The infrared spectra show gradual removal of the hydrocarbon bond (C-H), molecular H2O, and sianol group (Si-OH) with te mperature. TG, DTA, XRD and SEM were used in this study.