• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.100-110
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• 2016

Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treatment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabilizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less requirement of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hydrogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at the dosage level of 4.5% hydrogen peroxide exhibited an equal level of residual peroxide with BTMP. In conclusion, APMP pulping showed successful results with Pinus densiflora due to its better response to the development of optical and physical properties compared to TMP pulping.

• Journal of Korean Society of Forest Science
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• v.61 no.1
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• pp.27-36
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• 1983

This study was performed to get the basic information on nitric acid pulping of beech wood. In order to reduce the consumption of nitric acid, alkali pretreated woods were applied to a nitric acid pulping process. It consisted of nitric acid treatment to a high residual lignin content and the subsequent delignification with alkali, required far less chemical than the single stage method. At the first stage of nitric pulping, pulp yield descreased with increasing cooking time and 3 percent of nitric acid was more effective on the delignification of wood than 1 or 2 percent. Alkali pretreatment of wood improved significantly the rate of delignification, and 79 percent of the pretreated yield was good enough for excellent delignification. The dissolution of carbohydrate (mainly xylose) was increased with increasing cooking time, especially at the second stage. It would be considered that carbonyl groups introduced to polysaccharides in wood by nitric acid oxidation caused the degradation of carbohydrates.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.2
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• pp.24-33
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• 2015

This study aims to suggest wastewater treatment options for diaper recycling by identifying characteristic analysis of wastewater from diaper recycling process and efficiency evaluation of wastewater treatment units. The wastewater characteristic analysis showed that the concentration of organic pollutants and ionic materials were very high comparing to seawater. Through the investigation of similar wastewater treatment, six treatment units were identified to reduce pollutants. It is found UF(ultra-filtration), DAF(dissolved air flotation), fenton oxidation, electro-coagulation and chemical-coagulation are effective in reducing organic pollutants while membrane system and ion exchanger are effective in reducing ionic materials. Even though the target of water quality should be secured in terms of managing organic pollutants level, the application of treatment unit for reducing ionic material needs lots of considerations. This result suggests that reuse of pulping wastewater after controlling organic pollutants is better than direct discharge of pulping wastewater. To select the appropriate wastewater treatment unit, an economic analysis about operation condition, wastewater flow, cost, efficiency should be considered.

• Journal of Conservation Science
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• v.5 no.1 s.5
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• pp.3-10
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• 1996

In this study, bast fibers, woody parts and whole woods were pulped separately by alkali, alkali-hydrogen peroxide and sulfomethylated processes and their papermaking characteristics for the special Hanji were evaluated. Also properties of new Hanji products obtained from mixed stocks of various ratios were discussed. Solfomethylated pulps were shown higher brightness and sheet strengths than those from alkali and alkali-peroxide pulps. On the mechanical properties of Hanjis mixed with bast-and woody-parts pulps, and with bast and whole stem pulps, handsheet strengths were decreased with the increasing contents of woody and whole stem pulps. Various Hanjis could make by various mixing of separated cooked Pulps. Especially an excellant Hwaseonji(calligrapy Paper) could be made by one stage cooking of whole stem of paper mulberry by sulfomethylated pulping method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.14-22
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• 2016

Pulping is a stage that can change fibrous raw materials into pumpable slurry. Recovered paper can be defibrated to individual fibers by shear stress generated by rotation of a rotor and water. Disintegration of recovered paper is more complicated than that of chemical pulp. When disintegration of recovered paper is poor, screening and cleaning efficiency will be worse and properties of paper will also be deteriorated. Therefore, pulping is an important treatment for improvement of availability of recovered paper and process runnability. In this study, degrees of disintegration of KOCC obtained from a linerboard mill was analyzed with a pilot-scale screen. Flake removal of KOCC slurry was performed by a pilot screen. Simple pumping action gave a positive effect on disintegration of KOCC. After pumping for 10 minutes, paper strength increased without the change of water retention value and fibrillation of KOCC slurry. This phenomena can be explained by modification of hornified surface of KOCC fibers by shear stress generated by pumping. Consequently, disintegration efficiency of KOCC can be enhanced by control of retention time at pulper or an agitation power at chests of papermaking process.

• Journal of the Korean Wood Science and Technology
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• v.23 no.1
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• pp.13-20
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• 1995

This study was carried out to investigate the characterization of lignins from waste liquors in SP, KP, ASAM, and AS from Pinus densiflora, Quercus mongolica, and Betula ermanii. Spectroscopic study was applied to examine the lignins separated from different pulping process. Lignin contents in waste liqours increased in order of AS, ASAM, KP, and SP. UV spectra of three types of lignin except AS lignin showed similar pattern. IR spectra of AS lignin showed strong C=O absorptions in the range from 1730 to 1750$cm^{-1}$, where as those of KP, SP, and ASAM showed weak stretch in this region. NMR spectra of AS lignin showed strong characteristic chemical shifts of acetoxyl groups of acetylated aliphatic and aromatic hydroxyl groups at 2.0~2.5 ppm. Molecular weight of ASAM lignin from Pinus densiflora determined and found number average molecular weight 1,199, weight average molecular weight 5,458. z average molecular weight 17,242, and viscosity average molecular weight 5,457. It is considered from the results based on spectroscopic study of lignin that waste liquors (in SP, KP, ASAM and AS) from Pinus densiflora, Quercus mongolica, and Betula ermanii can be used for lignin utilization.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.73-80
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• 2015

Corn stalk is the lignocellulosic biomass, which remain as leftover after harvesting. To use the corn stalk as raw material for paper industry, soda pulping was applied. In chemical compositional analysis, extractive contents of corn stalk (45.1%) was higher than hardwood. With corn stalk pith, soda pulp yield was 25.3% at 10.6 Kappa number, but 39.5% yield with 14.8 Kappa number for corn stalk rind. Higher extractives content in pith is one of the reason for lower pulp yield than rind. Pith pulp fibers had higher fines content than rind pulp. Pith parenchyma cell was removed as fines during pulping or washing process, which caused the lower yield. To use the corn stalks as a raw material for paper making, de-pith process is essential for higher pulp yield and longer pulp length.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.2
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• pp.1-8
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• 2011

The presence of high silica in bamboo hinders the use of this material for production of rayon grade pulp. Research has been carried out to overcome this deficiency and improve quality of rayon grade pulp with the modification in pulping and bleaching process. Effect of acid boosted water prehydrolysis, sulphuric acid pre-treatment of unbleached pulp, chlorination stage at lower pH and treatment of bleached pulp with $SO_2$ water were evaluated. Acid boosted water prehydrolysis of chips reduces prehydrolysis time by 50 minutes as compared to water prehydrolysis. Treatment of unbleached pulp with sulphuric acid reduces ash, acid insoluble, silica, calcium and iron contents of the pulp by 56, 31, 82, 84 and 60% respectively. The addition of acid, increase in kappa factor in $C_D$ stage and combination of both were effective in removing silica in the pulp. Treatment of final bleached pulp with $SO_2$ water removes silica to a great extent and improves optical properties of the pulp as compared to $H_2SO_4$ or PAA. Pretreatment of the pulp with acid and modification in the bleaching process can reduce silica substantially and improve the quality of rayon grade bamboo pulp.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.102-108
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• 2008

At the University of Maine, a hemicellulose pre-extraction technology is now being investigated to improve pulp yields, reduce the organic and inorganic load for liquor recovery, and create a feed stream for the generation of new biomaterials. It is important to understand the composition of unextracted wood, extracted wood, and pulping extracts in the design of an economically viable pilot-scale ethanol plant. For analysis of wood pulp composition, the total analytical mass balance closure was 100.6, 100.3, and 81.6% for unextracted chips, extracted chips, and pulping extracts from HPLC-H column analysis. Meanwhile, the total analytical mass balance from the HPLC-P column was 97.8, 86.3, and 80.7%, respectively. This slight variability between H- and P-column results for analytical mass balance may be within the experimental error of the measurement. The data generated by this analysis are important to further design work in commercializing this process.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.44-50
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• 2016

As a raw material for pulp and paper industry, Moso bamboo, Timber bamboo and Henon bamboo pulps were prepared by soda or soda-anthraquinone(Soda-AQ) pulping process. Soda-AQ pulp yields was higher in Henon bamboo (43.2%) than in Moso bamboo or Timber bamboo (32.7-39.2%), but quite lower than hardwood species. In Kappa number comparison, Henon bamboo pulp showed lower (16.6) with 50 min cooking to $170^{\circ}C$ than that of Moso bamboo (22.8) and Timber bamboo (18.9) with 90 min cooking to $170^{\circ}C$. Fiber length of Timber bamboo soda pulp had higher (1.46 mm) than that of Moso bamboo or Henon bamboo (1.18-1.36 mm). All three bamboo pulps showed longer average fiber length than commercial hardwood pulp. With higher pulp yield and lower Kappa number, Henon bamboo is better raw material for pulp than Moso bamboo and Timber bamboo.