Fractionating: New Reveals of Stock Retention Mechanisms with Optimized Use of and Mixing of Additives in Paper and Board Production

摘要

A set of laboratory and field tests confirmed that a new novel method of combination of fractionating technology and fiber imagining is capable of evaluating function of retention chemicals in pulp suspensions. Retention chemical mechanisms were seen visually and it was observed that different chemicals have own role in binding fines and fillers. Fines and fillers are attached to fibers and especially to fibrillated fibers. Non-fibrillated fibers were seen basically plain - even after suspension chemical treatment. One important function is that fines and fillers are agglomerating as bigger particles between themselves and chemicals. This agglomeration will help particles to retain better in forming web. Results were logical according used retention chemical system. Conclusion from the second test is that this kind of measurements will give new tools also for board making where multiple plies are formed as a web. In board making different layers have different raw materials so retention systems can be optimized based on layer targets. Too often same retention program has been selected for all plies trying to balance the dosage rates on different plies. Fractionator studies showed evidence that especially for fines (and filler) retention different programs might need to be selected for optimum performance.