PCC Application Strategies to Improve Papermaking Profitability. Part 1. Thick Stock Precipitated Calcium Carbonate Addition, 2001 Papermakers Conference Proceedings

Continuous emphasis is being put on paper producers to improve margins. The predominate expense in paper production is the fiber cost and producers constantly look for ways to optimize the fiber component. One option is to replace the more costly fiber with cost-effective performance pigments.

Alkaline conversions using Precipitated Calcium Carbonate (PCC) were highly successful primarily because of the performance/value of PCC fillers. Additionally, alkaline paper producers use roughly twice as much PCC filler as they did under typical acid papermaking conditions. Paper producers continue to raise PCC filler levels in an effort to further reduce costs.

Five years ago, freesheet filler levels averaged about 13% and now average over 15% with some mills producing paper with filler levels as high as 25%. The primary drawbacks of filler for fiber replacement are the detrimental effect on paper strength and papermachine runnability. This work describes only one of many options for the papermaker to reduce/eliminate the mitigating effects when fiber is replaced with PCC.

This paper is the first of a series that discusses options to optimize fiber usage. This paper demonstrates that the dual addition of PCC to both the thin and thick stock results in higher fiber replacement with reduced negative impact on strength and papermachine runnability. Laboratory analyses and commercial case studies will be used to demonstrate that this is a viable option and is gaining broad acceptance in the paper industry.