Date of Award


Degree Name

Bachelor of Science


Paper Science and Engineering


The object of this study was to determine whether filler surface area or filler type has the greater effect on alkaline sizing efficiency. At a given surface area and sizing addition level, ground CaCO3 consistently gave higher sizing efficiency than clay. As the filler surface area increases the sizing efficiency decreases. At higher filler loadings there is a dramatic decrease in sizing response.

This report shows the following conclusions: CaCO3 gives higher sizing response than clay at a given surface area, both an increase in surface area and filler loading decreases sizing efficiency.

Many mills are going to or looking at alkaline sizing. It is recommended that these mills be aware that as they attempt to increase filler loading there will be a dramatic increase in sizing agent demand. Also, as the mills switch to ground CaCO3 they should be aware that better sizing results will be obtained than with clay at equivalent surface areas, filler loadings, and sizing addition.