Search Results

You are looking at 1 - 10 of 187 items :

  • "Retention aids" x
Clear All

PAPER PHYSICS New i ns ig hts i nto retention a ids dosage and mixi ng Paul Krochak, Susanne Schack, and Giuseppe Fasci KEYWORDS: Retention aids, Polymer degradation, Mixing, Shear stress, Approach flow SUMMARY: In this work, critical design and operational parameters for retention aids dosage are studied through a combination of computational fluid dynamics (CFD), experimentation and pilot-scale production trials . In the first part of this work, three different retention aids dosage strategies are investigated in conjunction with pilot scale

Cationic polyelectrolytes as retention aids in newsprint production Lennart Westman, Hans Grundmark and Jan Petersson, Holmens Bruk AB, Norrkoping, Sweden Keywords: Polyethylenimine, Thermomechanical pulps, Polyelectrolytes, Retention aids, Quality, Newsprint. SUMMARY: At Braviken Paper Mill, cationic polyelectro- lytes have been used as retention aids since 1980. The mill's production of newsprint is based on thermomechanical pulp (TMP) with spruce as raw material. The white water system carries high amounts of dissolved material, due to a high degree

The effect of various retention aids on retention and formation Anna Svedberg and Tom Lindström KEYWORDS: Drainage, Flocculation, Formation, Fourdrinier former, Kraft pulp, Pilot study, Polyacrylamide, Retention, Retention agent SUMMARY: The interdependency between retention and paper formation was studied using a previously designed R-F (Retention and formation)-machine. The objective of the work was to investigate the retention- formation relationship for different types of retention aid systems. Both single-component cationic polyacryl

515Nordic Pulp and Paper Research Journal Vol 15 no. 5/2000 Keywords: Fines retention, Filler retention, Microparticulate retention aid systems, Fiber flocculation, Kinetics of deposition, Bentonite, Polyacrylamide, Montmorillonite SUMMARY: The use of microparticulate retention aids was investigated in three different papermaking systems: the deposi- tion of PCC on kraft fibers, flocculation of TMP fibers and the deposition of fines on TMP fibers. It is shown that montmorillo- nite significantly increases both particle deposition and fiber floc- culation. This is

336 Nordic Pulp and Paper Research Journal Vol 19 no. 3/2004 KEYWORDS: AKD-sizing, Alkyl ketene dimers, Bleached kraft pulp, Radioactive labelling, AKD retention, Retention aids, AKD-dispersion SUMMARY: The effects of electrolytes and eight different cationic polymers on alkyl ketene dimer (AKD) size retention, extent of reaction and sizing efficiency were investigated using a C-14 labelled cationic AKD-dispersion. Sizing experiments were conducted in a standard British hand sheet former, using a Britt Dynamic Drainage Jar (BDDJ) to pre-shear the pulp suspension

, Sweden. The performance of chemical flocculants as retention aids in papermaking depends on factors such as the point of addition and the shear levels experienced. A high shear level leads to the break-up of flocs formed, which is beneficial for paper formation, but leads to the detach- ment of fillers deposited on fibres, thereby lowering the filler retention. A high degree of reflocculation when the high shear subsides would therefore be a desirable char- acteristic of a retention aid svstem. This is a feature that has been ascribed to the microparticle

Dynamic flocculation studies on fibre fines and filler clay Bjorn Krogerus, KCL Paper Science Centre, Espoo, Finland Keywords: Flocculation, Fines, Clay, Polyacrylics, Retention aids. SUMMARY: The flocculation characteristics of filler clay and of fibre fines derived from mechanical pulp were determined using a dynamic flow injection method. Flocculation was moni- tored using two Photometric Dispersion Analysers (PDA 2000s) coupled in series with an intermediate floc disruption stage between. In this way the initial flocculation, the floc strength under

The effects of retention aid distribution in the furnish Robert A. Stratton and Charles E. Miller, Institute of Paper Science and Technology, Atlanta, Georgia, USA Keywords: Retention aids, Polystyrene, Linters, Polyacrylics, Acrylamide, Electrophoresis. SUMMARY: The point of addition of retention aids to the papermaking system and the degree of agitation at that point determine which surfaces of the stock become treated and the uniformity of the treatment. To ascertain the importance of these parameters on the extent of retention, we studied a simple

PAPER PHYSICS Nordic Pulp & Paper Research Journal Vol 30 no (2) 2015 296 Forming fabric weave-scale variations in paper fines content Fatehjit Singh and Sheldon I.Green KEYWORDS: Fines distribution, Fluorescence micro- scopy, Forming fabric, Retention aids. SUMMARY: During papermaking pulp suspension drains through the forming fabric to create a wet pulp mat. A series of experiments were conducted to investigate the small-scale variation in fines distribution caused by the forming fabric’s weave structure. Pulp fines are first separated from the

710 Nordic Pulp and Paper Research Journal Vol 21 no. 5/2006 KEYWORDS: Retention aids, Deposits, Newsprint, Furnish, Waste papers, Evaluation, Deinked stock SUMMARY: In addition to their usual functions of improving retention and drainage, retention aids are frequently used by industry to control deposits. Evaluating retention aid perfor- mance is an important aspect of optimizing paper machine ope- ration. For mills employing deinked pulp (DIP), containing recycled newspaper and old magazine grade paper (which is often coated), such an evaluation is complex, due