Effect of thermal treatment on the structure of PCC particles

Abstract

The controlled combustion of paper is normally used to determine the filler content of paper. It can also be a valuable tool to isolate the mineral particles for extra characterization or additional applications. However, the ashing temperature greatly affects the filler particles. The main goal of this study was to analyze the effects of paper calcinations on the intrinsic properties of precipitated calcium carbonate filler (PCC) at distinct temperatures, from 400°C up to 1000°C. We characterized the size, density, surface area, porosity, chemical composition, color, and electrostatic charge of the original PCC particles and the ash. The experimental results revealed that for a calcination temperature of 400°C, the size, specific surface area, and porosity of the ash are similar to those of the PCC filler before being incorporated in paper. Other important filler properties, such as color and electrical charge, are much different. To overcome this disadvantage, higher ashing temperatures need to be used. This study has demonstrated that 600°C is the optimum temperature for isolating the paper fillers, without the collapse of the PCC structure, so that their physical, chemical, optical, and electrical characteristics are adequately balanced and not too different from those of the original particles. Application: This study demonstrates the effects of thermal treatment on the structure of PCC particles and evaluates the potential of the ashing method to isolate these particles from filled papers.