Economical and efficient use of fly ash for newsprint paper quality improvement

Abstract

This research focused on the production of a novel calcium silicate pigment made from pulverized coal fly ash and its application as a coating pigment in a size press for fiber replacement. Improved specific base paper properties of the newsprint was investigated. This novel coated fly ash based calcium silicate (FACS) pigment and conventional precipitated calcium carbonate (PCC) pigment was applied using a cylindrical laboratory coater. When a 4.3 gsm coat weight of FACS was used during the size press application, the brightness increased 10 points, whereas, when the coat weight of FACS was increased to 7.8 gsm, the brightness increased to 21 points as compared to base newsprint sheet; however, FACS brightness was lower than the PCC coated newsprint sheet. Also, there was a significant gain in other newsprint specific base properties when fly ash based pigment was used. This indicated that it is feasible to utilize a novel fly ash based pigment in the size press coating application to replace fiber in order to reduce production cost, improve specific base properties, and reduce environmental pollution. To the authors’ knowledge, this is the first study reporting the application of fly ash as a coating pigment for quality enhancement of newsprint.