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The effect of contact time between CPAM and colloidal silica on the flocculation behavior in the approach flow, TAPPI Journal January 2021
ABSTRACT: Multicomponent wet-end systems have become increasingly common in papermaking, with the objective of improving the retention-formation-dewatering relationship. It is quite common to use at least a cationic polymer, often in combination with an anionic microparticle. In some cases, a fixative is also used. However, there is still debate on the optimal implementation of these systems. In particular, optimizing the contact time of the cationic polymer prior to addition of the anionic microparticle is still poorly understood. In this work, we investigate the effect of the contact time of a cationic polyacrylamide (CPAM) prior to addition of colloidal silica on the flocculation response in a flowing fiber suspension. The effect of using a fixative is also investigated. Focused beam reflectance measurements (FBRM) are combined with zeta-potential measurements for optimizing the addition levels of a two- and three-component system, as well as for elucidating the effect of contact time on CPAM performance. Trials are then performed on a pilot scale flow loop, where the time between addition of these two components is varied and the resulting flocculation response is characterized using high-speed filming and image analysis techniques. It is shown that the efficacy of CPAM can be improved through use of a fixative and that a longer CPAM contact time may be beneficial in terms of immediate flocculation; however, hydrodynamic shear tends to dominate the flocculation response regardless of contact time due to floc rupture.
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Co-ground mineral/microfibrillated cellulose composite materials: Recycled fibers, engineered minerals, and new product forms, TAPPI Journal January 2021
ABSTRACT: When pulp and minerals are co-processed in suspension, the mineral acts as a grinding aid, allowing costeffective production of mineral/microfibrillated cellulose (MFC) composite materials. This processing uses robust milling equipment and is practiced at industrial scale. The resulting products can be used in many applications, including as wet- and dry-strength aids in paper and board production.Previously, we have reported that use of these MFC composite materials in fiber-based applications allow generally improved wet and dry mechanical properties with concomitant opportunities for cost savings, property improvements, or grade developments. Mineral/MFC composites made with recycled pulp feedstocks were shown to offer at least equivalent strength aid performance to composites made using virgin fibers. Selection of mineral and fiber allows preparation of mineral/MFC composites with a range of properties. For example, the viscosity of such formulations was shown to be controlled by the shape factor of the mineral chosen, effective barrier formulations were prepared, and mineral/MFC composites with graphite as the mineral were prepared.High-solids mineral/MFC composites were prepared at 75% total solids (37% fibril solids). When resuspended and used for papermaking, these high-solids products gave equivalent performance to never-dried controls.
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Over the Wire, Paper360º January/February 2021
Over the Wire, Paper360º January/February 2021
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At WestRock, Safety is Universal At WestRock, Safety is Universal, Paper360º January/February 2021
At WestRock, Safety is Universal At WestRock, Safety is Universal, Paper360º January/February 2021At WestRock, Safety is Universal At WestRock, Safety is Universal, Paper360º January/February 2021
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Coming Out of the Coronavirus Pandemic, Paper360º January/February 2021
Coming Out of the Coronavirus Pandemic, Paper360º January/February 2021
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Coarse Filtration is the ´First Line of Defense’, Paper360º January/February 2021
Coarse Filtration is the ´First Line of Defense’, Paper360º January/February 2021
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3 Ways to Minimize Digital Risk, Paper360º January/February 2021
3 Ways to Minimize Digital Risk, Paper360º January/February 2021
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TAPPI Journal Summaries, Paper360º January/February 2021
TAPPI Journal Summaries, Paper360º January/February 2021
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RMM Part 2: Belief-Driven Strategy, Paper360º January/February 2021
RMM Part 2: Belief-Driven Strategy, Paper360º January/February 2021
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TAPPI News, Paper360º January/February 2021
TAPPI News, Paper360º January/February 2021