Comparative Analysis of Ultra-Fine Bar Refining and Valley Beating on Softwood and Hardwood Kraft Pulps: Implications for Fiber Integrity and Paper Strength Enhancement
Source abstract
Abstract
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.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Advanced Cellulose Research Studies · Material Properties and Processing · Lignin and Wood Chemistry
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Forest Products, Gyeongsang National University, Jinju 52828, Republic of Korea
Department of Forest Products, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju 52828, Republic of Korea
Department of Pulp&Paper Chemical Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
Funding
National Research Foundation of Korea (NRF) · Ministry of Education · Korea Basic Science Institute (National Research Facilities and Equipment Center)
References (32)
Show source-provided references
1. Mechanisms of strength and stiffness improvement of paper after PFI refining with a focus on the effect of fines10.1007/s10570-019-02349-5 ↗
2. Paper’s strength: A review
3. Quantifying the contribution of fines production during refining to the resulting paper strength10.1007/s10570-022-04809-x ↗
4. The measurement and significance of fines
5. Smook, G.A. (2016). Handbook for Pulp & Paper Technologists, TAPPI Press. [4th ed.].
6. Basic Effects of Pulp Refining on Fiber Properties—A Review10.1016/j.carbpol.2014.08.047 ↗
7. Effect of Pulp Properties on the Power Consumption in Low Consistency Refining10.5658/WOOD.2020.48.6.869 ↗
8. A comparative study of the effect of refining on charge of various pulps10.1016/j.biortech.2010.12.109 ↗
9. Optimization of Mixed Pulp Stocks for Paper Strength and Smoothness
10. Lightweight Refiner Plate for Hardwood Kraft Pulp Fibers
11. New technology for developing a lightweight refiner plate for hardwood kraft pulp fibers10.15376/biores.15.4.9128-9142 ↗
12. Development of a lightweight vertical bar plate for softwood kraft pulp refining
13. Zhang, L., Wang, Q., Chen, S., and Li, H. (2021). Effects of Beating and Refining on Fiber Characteristics and Paper Properties of Hardwood-Softwood Blended Pulps. Materials, 14.
14. Optimization of Mixed Pulp Stocks for Enhanced Paper Properties
15. Lehtinen, E. (2000). Papermaking Part 1, Stock Preparation and Wet end. Papermaking Science and Technology, Tappi and PPI.
16. (2016). Pulps—Laboratory Beating—Part 1: Valley Beater Method (Standard No. ISO 5264-1:2016).
17. Study of Mixed Refining Behaviors of Softwood Kraft Pulps and Hardwood Kraft Pulps Using Different Bar Fillings10.7584/JKTAPPI.2018.10.50.5.31 ↗
18. Mechanical modification of softwood pulp fibers using a novel lightweight vertical bar plate10.32964/TJ20.4.241 ↗
19. Ryu, J.H., Kim, C.H., Lee, J.Y., Lee, C.Y., and Park, J.H. (2022). Study of Refining Effect of Mixed Pulps Using Refiner Plates with Different Bar Pattern. Appl. Sci., 12.10.3390/app122211445 ↗
20. (1999). Pulps—Determination of Drainability—Part 1: Schopper-Riegler Method (Standard No. ISO 5267-1:1999).
21. (2005). Pulps—Preparation of Laboratory Sheets for Physical Testing—Part 1: Conventional Sheet-Former Method (Standard No. ISO 5269-1:2005).
22. (2022). Pulps—Laboratory Sheets—Determination of Physical Properties (Standard No. ISO 5270:2022).
23. Characterizing the action of refiner bars
24. Characterizing refining action in PFI mills
25. The influence of bar width on bar forces and fiber shortening in low-consistency pulp refining10.1515/npprj-2018-3028 ↗
26. Mohlin, U.B., and Miller, J.A. (1995). Effects of refining on pulp fiber structure. Handbook of Physical Testing of Paper, Marcel Dekker. [1st ed.].
27. The mechanism of the beating process
28. A comparison of Valley beating and PFI refining
29. Bolam, F. (1961). The beating process: Primary effects and their influence on pulp and paper properties. The Formation and Structure of Paper, Transactions of the 2nd Fundamental Research Symposium, Oxford, UK, FRC.10.15376/frc.1961.2.651 ↗
30. Lumiainen, J. (2025, April 01). Papermaking Part 1, Refining of Chemical Pulp. Available online: https://turbulence-initiated.sites.olt.ubc.ca/files/2013/01/1998-Lumiainen-Ch4.pdf.
31. The proper evaluation of the beating of pulps
32. Effect of combined refining plates with different bar angles on paper properties during mixed pulp refining10.5658/WOOD.2020.48.5.581 ↗