Laboratory and Machine Trial Comparison of Novel Inorganic Cationic Microparticle Retention Systems, 1999 Papermakers Conference Proceedings

C. Ovenden, H. Xiao, N. Wiseman

To improve the effectiveness in retaining the fine mineral fillers such as calcined clay with fibres, a novel inorganic cationic microparticle retention system based on the synthetic water-based colloidal alumina has been developed in this work. A photometric dispersion analyser in combination with a dynamic drainage jar has been used in characterising the filler flocculation in the presence/absence of fibres in our laboratory experiments. It has been found that only limited clay flocculation was induced by the inorganic cationic microparticles alone. However, the flocculation was significantly improved in conjunction with an anionic polyacrylamide of high molecular weight and low charge density. Moreover, the cationic microparticle/anionic polymer retention systems are insensitive to shear stress and pH at the normal papermaking conditions. The filler retention was also evaluated on the Pilot Plant Papermachine at UMIST. The machine trial was monitored on-line with a BTG consistency meter which dynamically recorded the backwater solids and the ash content. By comparing the retention performance, it has been found that good agreement with the laboratory results was obtained during the pilot machine trial. .