Practical Experiences in Additive Screening Using a Torque-Based Flocculation Analyzer, 2001 Papermakers Conference Proceedings

Many laboratory devices and methods have been developed for evaluating retention and drainage aid performance. This paper describes results from in-mill polymer screening experiments utilizing a novel flocculation analysis technique. This method is useful for measuring the impact of typical papermaking additives on the degree of flocculation and the resulting floc’s resistance to shear. As a sample is stirred at a constant speed, a retention aid is added and flocs begin to form. These flocs increase the load on the motor, which is driving the impeller. Therefore, the degree of flocculation, which is proportional to the increase in load, can be measured in real time. As the impeller gradually destroys the flocs, a decrease in load is detected, which is related to the floc’s strength or resistance to shear. Results from various retention aid chemistries and various papermaking furnishes are discussed. Sensitivity to product dosage and chemistry was observed, as well as a good correlation with Britt jar retention.