Appl. Sci. 2025 , 15 , 9160
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inform industry practices and support the development of more efficient and sustainable papermaking technologies.
2. Materials and Methods 2.1. Raw Materials
Hardwood bleached kraft pulp (HwBKP) and softwood bleached kraft pulp (SwBKP) were supplied from Moorim Paper Co., Ltd. in Jinju, Republic of Korea. They were torn into small pieces and soaked in distilled water for over 4 h before disintegration to ensure proper hydration and ease of fiber separation. This step also helps reduce energy consumption during disintegration and maintains the intrinsic properties of the fibers [16]. The fiber characteristics of these two raw materials are summarized in Table 1. While softwood and hardwood kraft pulps exhibit more pronounced differences in fiber morphol- ogy than in chemical composition, both types of data were examined in this study.
Table1. Fiber characteristics of HwBKP and SwBKP used for beating and refining.
Length-Weighted Mean Fiber Length (mm)
Arithmetic Fines Contents ( ≤ 0.2mm) (%)
Arithmetic Mean Fiber Length (mm)
Coarseness (mg/m)
HwBKP SwBKP
0.5 1.3
0.7 2.3
31 28
5.8
15.5
Table 2 shows the chemical compositions of HwBKP and SwBKP. However, since these differences had little effect on the beating and refining results of SwBKP and HwBKP, the data in Table 2 were not further discussed in this study.
Table2. Chemical composition of HwBKP and SwBKP used for beating and refining.
Cellulose (%)
Hemi-Cellulose (%)
Lignin (%) 0.3 ± 0.13 0.3 ± 0.12
Extractives (%)
HwBKP SwBKP
83 ± 1.24 86 ± 1.81
20 ± 0.91 13 ± 0.45
0.3 ± 0.13 0.1 ± 0.11
2.2. Beating and Refining Before beating, the soaked pulp specimen underwent disintegration. This was ac- complished using a Valley beater (Daeil Machinery Co., Inc., Daejeon, Republic of Korea) without any applied load, maintaining a pulp consistency of 1.57 ± 0.04% for at least 3 to 5 min, following ISO 5264-1 [17]. After disintegration, the pulp was beaten within the Valley beater (refer to Figure 1) with a 5.5 kg load at around 500 rpm until the target refining level of around 190 mL CSF. The specific dimensions of the Valley beater are shown in Figure 2 and Table 3. The width of the flybars is 4.8 mm, and the width of the bars on the bedplate is 3.2 mm. The groove width between the flybars is 12.25 mm, and the groove width between the bars on the bedplate is 2.4 mm.
Table3. Specific dimensions of the laboratory Valley beater.
Roll with Flybars
Bedplate
Roll diameter with fly bars: 193.8 mm
Number of bars: 7 Bar width: 3.2 mm Bar height: 159 mm Groove width: 2.4 mm
Roll width: 4.8 mm Roll length: 152.4 mm Number of flybars: 32 Flybar height: 10 mm
Angle between the roll axis and bed plate: 5 ◦
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