Improve the Quality of the Paper with a Surface Coating of Silica in Rice Husk

Rice husk is a form of agricultural biomass that provides an abundant silicon dioxides source. This study used rice husk ash as a material to prepare paper coating. Silica powder has been synthesized by the refluxing of rice husk ash with HCl 1,2 and 3 M at different time (60 and 120 min.) The silicon dioxide extraction yield reached 85% and was effect by concentration of HCl solution and reaction time. The structure of the obtained silica powder were characterized by X-Ray Fluorescence (XRF), Particle size distribution (PSD), X-Ray diffraction (XRD), CIE L*a*b* (Visible spectrophotometer) and Scanning Electron Microscope (SEM). The highest purity of silica sample were 98.7% SiO2, CIE L*a*b* = 94.79 +0.48 +1.24, ∆E ≈ 3.28 (white powder) and 2Ɵ = 22o (silica). Particle had a uniform size less than 3 μm. The paper coating was made from acrylic resin mixed with synthesized silica that refluxing by HCl 2 M 120 min at different ratio (2%, 4% and 6%) and paper coated with a gravure printing machine. The qualities of paper coating were analyzed from viscosity, Transparency (Density) and color gamut of inkjet printing. The paper coating that mixed synthesized silica from rice husk 4% was highest qualities because have viscosity 358 ± 24.99ctp., Density = 0.19, and widely color gamut.