PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® FROM THE PUBLISHERS OF PAPER TEC Volume 12, Number 1, 2026
Comparative Analysis of Ultra-Fine Bar Refining and Valley Beating on Softwood and Hardwood Kraft Pulps: Implications for Fiber Integrity and Paper Strength Enhancement HYEONG-HUN PARK 1 , CHUL-HWAN KIM 2 , JU-HYUN PARK 1 , MIN-SIK PARK 1 & JAE-SANG LEE 3 This study compared the effects of refining with an ultra-fine bar plate and Valley beating on softwood (SwBKP) and hardwood (HwBKP) bleached kraft pulps. Ultra-fine bar refining reduced pulp freeness from 700 mL to 200 mL CSF in just 10 min for both SwBKP and HwBKP, whereas Valley beating required over 60 min to reach comparable freeness levels. At equivalent freeness (e.g., 300 mL CSF), refining resulted in a tensile strength increase of approximately 35% for SwBKP and 20% for HwBKP compared to beating. In addition, refining delivered higher burst and tear strengths across all tested freeness levels, while better preserving fiber length. The results clearly demonstrate that refining with an ultra-fine bar plate achieves faster development of desirable paper properties and superior strength enhancement relative to Valley beating for both softwood and hardwood kraft pulps. These findings emphasize the importance of direct refining trials and plate optimization for improving pulp quality and energy efficiency in papermaking. Contact information: 1. Department of Forest Products, Gyeongsang National University, Jinju 52828, Republic of Korea. 2. Department of Forest Products, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju 52828, Republic of Korea. 3. Department of Pulp & Paper Chemical Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea. Appl. Sci . 2025, 15, 9160 https://doi.org/10.3390/app15169160 Creative Commons Attribution 4.0 License
The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International ® and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .
Article 7 – Refining
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