The potential of fly ash-based calcium silicate as paper filler: Physical properties and printability

Abstract

The development and application of low-cost and high-performance fillers by the paper industry is one of the most interesting aspects of filler technology. A novel calcium silicate, a byproduct, known as fly ashbased calcium silicate (FACS), from the value-added use of fly ash of coal-fired power plants, can be used as paper filler. To simulate the industrial papermaking process, a dynamic sheet former was used to evaluate the effect of FACS on the physical properties and printability of calendered paper. The results were compared with those of commonly used fillers, i.e., ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC). FACS-filled paper delivered a higher bulk than GCC-filled or PCC-filled papers at a given paper roughness. In addition, use of the original FACS exerted less influence on the tensile and tear strength of the filled paper. Printing quality tests indicated that at the same print density, the ink demand of FACS-filled paper was higher than that of GCC-filled or PCC-filled papers, but lower print through was obtained at the same amount of ink transferred to paper. The paper sheets containing the original FACS exhibited better surface strength than PCC-filled sheets. The results support the potential use of FACS as a low-cost filler for fine paper production.