Appl. Sci. 2025 , 15 , 9036
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Table1. Chemical components of KOCCs.
α -Cellulose
Lignin
Contents (%) 12.3 ± 0.4 After removing adhesive tapes, labels, and other extraneous materials from the col- lected corrugated boxes, the boxes were torn into small pieces approximately 5 × 5 cmin size. These pieces were then soaked in distilled water at a consistency of for a minimum of 2 h to ensure adequate hydration and facilitate fiber separation during the disintegration process. Prior to refining, the soaked pulp specimens underwent disintegration using a laboratory Valley beater (Daeil Machinery Co., Inc., Daejeon, Republic of Korea) operated without any applied load. The pulp consistency was maintained at 1.57 ± 0.04% for a duration of at least 3 to 5 min, in accordance with ISO 5264-1 standards [17]. 66.6 ± 0.2 2.2. Refining After processing the pulp fibers using the Valley beater, excess water was removed to adjust the slurry concentration to 4–5% in accordance with ISO/TS 11371 [18]. The thickened stock was then processed in a single disk refiner (KOSWON Co., Gimhae, Republic of Korea) equipped with two distinct plate patterns, as shown in Figure 1 and detailed in Table 2. The first was a conventional cast plate with a cutting edge length (CEL) of 37 km/s, designed for hardwood pulps, a bar angle of 28 ◦ , bar width of 2.5 mm, groove depth of 6 mm, and 198 bars in total. The second was an ultra-low-intensity plate (ultra-fine bar plate) with a CEL of 97 km/s, a bar angle of 52 ◦ , a bar width of 1 mm, a groove depth of 7 mm, and 480 bars, utilizing an aluminum alloy plate base and stainless alloy bars. Table 2 presents all critical plate parameters, allowing for a direct comparison of bar dimension, groove depth, bar angle, plate diameter, bar number, and CEL for both plate types. Refining was conducted at 800 rpm, with the goal of achieving a Canadian freeness level of approximately 190 mL, as specified by ISO 5267-2 [19].
Figure 1. Comparative analysis of stock throughput (g/s) versus specific refining energy (kWh/t) for KOCCs at CELs of 37 km/s and 97 km/s.
Table2. Comparison of the refiner plates with different bar fillings.
Conventional Cast Plate
Ultra Low Intensity Plate
Plate design
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