Please refer to two web site papers,"Process Chemistry Optimization, CFS Process, Revision I", and to "Economic Benefits of Zeta Data Technology."

The study on chemistry optimization was conducted with guidance from members of the technical staff of a major Satellite PCC supplier before and during its execution. The paper on economic benefits received significant input from the industry itself.

The general sense of the conclusions is:

1. Major benefits are realized by operating at the optimum zeta potential

2. The benefits fall off rapidly on either side of optimum

1. DCS control of chemical feed rates enables continuous chemistry optimization
2. Among the benefits are higher sheet ash coupled with greater strength (!)
3. Sizing efficiency can be increased by an order of magnitude (!)
4. The benefits can lead to cost savings running well into 7-figures (!)
5. Sizing efficiency can be increased by an order of magnitude (!)
6. The benefits can lead to cost savings running well into 7-figures (!)

There is a well-known saying, "If it sounds too good to be true, it is," which applies to this case, but only because the papermaker is not willing to adjust chemical feed rates to maintain optimum zeta potential. The papermaker is only willing to monitor the process with, for example, a Mutek ($70K) or in Finland with a WICK ($1000K), and is content to simply stabilize the process, so as to keep the machine "running well." With the exception of one important sector, papermakers are not pro-active, and do not adjust chemical feed rates to optimize zeta potential.

The monitoring technologies do not measure zeta potential and therefore lack the capability of obtaining the ideal value, much less maintaining it at the sensitive optimum point, a task exacerbated by feedstock of variable quality. Fortunately, there is the exception that proves the rule. The decorative laminate industry, which typically operates with 50+% headbox ash as TiO_2, has such a terribly difficult process that they can only function efficiently at the optimum zeta potential.

My firm has been instrumental in supplying lab zeta potential instruments (the Laser Zee) to this industry sector beginning in the early 70's and on-line zeta potential instruments (the Zeta Data) beginning in the early 90's. I have visited 9 or 10 such mills in 7 countries and only observed the zeta potential charge measurement..

The papermaker fully realizes that he must give close attention to the imperatives of physics. When he becomes persuaded to pay equally close attention to the imperatives of chemistry, he can achieve quality, process and cost benefits currently considered "too good to be true."

The nitty gritty specifics were spelled out in last month's Newsletter, entitled "Harmonizing the Physics and Chemistry of Papermaking." It deserves your attention.

John G. Penniman,