Negin Ghahrani; Noradin Nazarnezhad; Omid Ramezani; Ghasem Asadpour
Abstract
Regeneration of cellulose by direct solvent dissolution essentially involves the pretreatment of cellulose with a solvent for swelling the cellulose chains and weakening the cellulose molecules bonds. Aqueous solutions based on sodium hydroxide (NaOH) are low cost, non-volatile, non-toxic, environmentally ...
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Regeneration of cellulose by direct solvent dissolution essentially involves the pretreatment of cellulose with a solvent for swelling the cellulose chains and weakening the cellulose molecules bonds. Aqueous solutions based on sodium hydroxide (NaOH) are low cost, non-volatile, non-toxic, environmentally friendly cellulosic solvent with fast dissolution power at low temperatures. The mechanism of cellulose dissolution in this solvent is not yet fully understood because there are parameters such as temperature, crystallization and degree of cellulose polymerization that affect the solubility of cellulose in the NaOH / urea system. Therefore, this study investigated the effect of kappa factor changes in chlorine dioxide bleaching on the dissolution of OCC recycled pulp on chemical compounds (lignin and hemicellulose) and the degree of polymerization. The results showed that with further reduction of lignin, the dissolution of pulp decreases and this reduction in dissolution is more severe in lignin levels below 3% (reduction from 44% to about 37% dissolution). It seems that during the bleaching process and part of lignin and hemicellulose removal, a part of cellulose with low degree of polymerization is also removed and the average polymerization of the remaining cellulose increases which is more resistant to the phenomenon of pulp dissolution. With increasing kappa factor (to 0.2 and 0.3), there was no significant change in dissolution and hemicellulose. In general, it seems that lignin and the degree of polymerization are not only the effective factors in OCC pulp dissolving and hemicellulose content also can be effective.
Pulp and paper
Hossein Resalati; Mostafa Nikkhah Dafchahi
Abstract
Due to shortage of harvestable forest wood in Iran, the potential of CMP pulp production from various species of salix (alba, fragilis and aegyptica), in comparison with populus deltoides, was investigated across this research work. The cooking liqour of Mazandaran wood and paper Mill, consisting of ...
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Due to shortage of harvestable forest wood in Iran, the potential of CMP pulp production from various species of salix (alba, fragilis and aegyptica), in comparison with populus deltoides, was investigated across this research work. The cooking liqour of Mazandaran wood and paper Mill, consisting of 50:50 ratios of sodium sulfite and sodium bisulfite, and hydrogen peroxide, were used for Chemical treatment and bleaching of the pulps, respectively. The results showed that the paper pulps of fragilis salix and alba salix had higher bulk and lower opacity than other species, respectively. From the strength properties point of view, the highest and lowest tensile strength of produced papers were related to alba and fragilis species, and, the highest and lowest burst and tear strength of the prepared papers have belonged to Salix aegyptica and Populus species, respectively. The data have shown that Salix species have a good pothential to be used as raw material to produce CMP pulp at the cooking yield of 85%. According to the results of this research work, alba salix and aegyptica salix are in first and the second priority to produce CMP pulp ,at the cooking yield of 85%, respectively.
Pulp and paper
Ramin Vaysi; Mohammad Nikkar; Hamidreza Salarian
Abstract
In this study, the possibility of using ash and orange bleached CMP pulp as replace in the full or part of CMP pulp of Mazandaran Wood and Paper Industries (MWPI) for making newsprint was investigated. For this purpose, first, ash and orange CMP pulps were prepared by using cooking conditions of MWPI ...
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In this study, the possibility of using ash and orange bleached CMP pulp as replace in the full or part of CMP pulp of Mazandaran Wood and Paper Industries (MWPI) for making newsprint was investigated. For this purpose, first, ash and orange CMP pulps were prepared by using cooking conditions of MWPI with 101 gr/lit Na2O at the yield 85% in 75 minutes. Then some of the CMP pulps bleached with hydrogen peroxide, then its mixed samples with 15, 30, 45 and 60 percent to CMP pulp mill (control sample). From the mixed pulps provided hand sheets with 60 gr/m2 and these optical and mechanical properties measured and the data average were analyzed and compared. The results showed that newsprint from ash CMP pulp were more suitable than CMP pulp mill in all measured properties (except brightness) and orange CMP pulp (except opacity). Following bleaching with hydrogen peroxide, the brightness, tear, burst, tensile and breaking length strengths increased and opacity decreased. The results showed that ash and orange unbleached CMP pulps are not good properties for newsprint production and these pulps have to bleach with hydrogen peroxide. In generally, the best mixed pulps were includes 45-60 percent ash and orange bleached CMP pulps with 40-55 percent MWPI CMP pulp for newsprint production.
Pulp and paper
Mohtaba Goli; Majid Zabihzadeh; Saeed Mahdavi; Hassan Sadeghifar
Abstract
The objective of this study was determination of the best method of bleaching including refining and bleaching (RB) or bleaching and then refining (BR) on chemical mechanical pulp (CMP) for the production of newsprint. Wood raw material consists of mixed wood forest species was chipped and air dried ...
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The objective of this study was determination of the best method of bleaching including refining and bleaching (RB) or bleaching and then refining (BR) on chemical mechanical pulp (CMP) for the production of newsprint. Wood raw material consists of mixed wood forest species was chipped and air dried to calculate the moisture content. Wood composition percentages for CMP pulping was 40% poplar, 30% maple, 7.5% oak, 7.5% alder, 7.5% willow, and 7.5% Persimmon. In order to remove heavy metal ions of pulp, the chelating was carried out with DTPA. TCF Bleaching carried out by 3% H2O2 and 2.5% NaOH based on dry weight of pulp with initial brightness of 44.6% ISO. Pulp bleaching was done in two stages, before and after the refining by laboratory PFI mill beater. Finally, handsheets were made from the RB and BR treated pulps and the sheet properties were evaluated according to TAPPI test methods. The results showed that BR treatment increased tensile, burst, tear indices, brightness, scattering coefficient, and density, but reduced yellowing, opacity, and light absorption coefficient. The results confirmed the conventional method of CMP pulp treatment (BR) in MWPI.
Pulp and paper
Afshin Veisi; Saeed Mahdavi; Mohammad Talaeipoor
Abstract
In this study, production of bleached chemical- mechanical pulp from wheat straw for newsprint papermaking was investigated. Wheat straw for pulping was obtained from Lorestan province. Wheat straw CMP pulp was prepared at 120, 140, and 160 °C temperature, 45 minute time, 10, 12, and 14% chemicals ...
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In this study, production of bleached chemical- mechanical pulp from wheat straw for newsprint papermaking was investigated. Wheat straw for pulping was obtained from Lorestan province. Wheat straw CMP pulp was prepared at 120, 140, and 160 °C temperature, 45 minute time, 10, 12, and 14% chemicals charge and 10:1 cooking liquor and straw ratio. The yield after defibration treatment varied between 56.5% and 72.5%. Two optimum pulps bleached by TCF method applying 2% and 3% NaOH, 1.5% and 2% H2O2, and 60 and 120 minutes bleaching time. One way analysis variance method showed that bleaching time had the most significant effect on optical properties of handsheet. Applying 3% (based on oven dry weight of the unbleached pulp) NaOH, 2% H2O2, and 120 min. in bleaching improved the brightness and opacity to 52.9%, and 79.5% ISO, respectively. Optimum pulp strengths including tensile, burst and tear indices were measured 43.87 Nm/g, 2.18 kPa.m2/g, and 8.46 mN.m2/g, respectively. All the strengths were higher than newsprint paper strength produced by Mazandaran wood and paper and Korean companies.
Pulp and paper
Ramin Veisi; Iman Khajeh ali
Abstract
This study and it aim was accomplished on extraction, identification and removal of metallic ions and resins in bleached Bagass pulp by ECF stages. For this purpose, the samples were randomly selected from soda unbleached pulp of Pars mill. The first, pulp flour provided and measured ash and extractive ...
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This study and it aim was accomplished on extraction, identification and removal of metallic ions and resins in bleached Bagass pulp by ECF stages. For this purpose, the samples were randomly selected from soda unbleached pulp of Pars mill. The first, pulp flour provided and measured ash and extractive percent by the TAPPI standards. Then the mineral compounds dissolved in 65% nitric acid and the mineral compounds of pulps identificated by Atomic adsorption method. The results of this study showed that the most of Pb, Cu, Zn ions were in H2O2 bleached pulp, the most of Ni ion in OD(Ep)P stage and the most of Fe ion in unbleached soda pulp. The results showed that OD(Ep)D stage decrease Fe ion and EH stage decrease Ni, Cu and Zn ions in pulps. The results of GC-MS diagram showed that 35 compounds were identified in unbleached soda pulp after cooking, that 1,2-Benzendicarboxylic acid, Hexadecanoic acid, Hexadecan, Octadecan, p-Xylene, 4-Hydroxy-4-Methyl-2-Pantanone,Ethylbenzen and Dodecan were important chemical components in samples. In generally, 17,12 and 14 compounds were identified in EH, OD(Ep)P and OD(Ep)D bleaching stages, respectively, so that, 1,2-Benzendicarboxylic acid and p-Xylene were 2 common and important chemical components in all samples and Octadecan and 9-Dodecanoic acid remove as two components from pulps after bleaching, too. The results showed that EH, OD(Ep)P and OD(Ep)D bleaching stages were very important in bleaching, removal of chemical components and brightness stability of soda pulps.
Pulp and paper
Mostafa Nikkhah Dafchahi; Hossein Resalati
Abstract
This research was performed to evaluate the potential of acid pre-hydrolysis soda-AQ process for the production of dissolving pulp including high α-cellulose content from Populus deltoides. To achieve the aim, a pre-hydrolysis liquor containing 0.06% acid sulfuric, soda-AQ pulping, and OD0ED1 bleaching ...
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This research was performed to evaluate the potential of acid pre-hydrolysis soda-AQ process for the production of dissolving pulp including high α-cellulose content from Populus deltoides. To achieve the aim, a pre-hydrolysis liquor containing 0.06% acid sulfuric, soda-AQ pulping, and OD0ED1 bleaching sequence were used. The results show that using at least 0.40 kappa factor at D0 stage was necessary to gain access a high quality dissolving pulp including characteristics like having brightness level and α-cellulose content higher than 86% and 98%, respectively. A kappa reduction of 40.3% was achieved by performing a single stage oxygen delignification after soda-AQ pulping to drop kappa number of pulp from 14.1 to 8.4 prior to entrancing the pulp into the final bleaching stage. The results illustrated that producing acid pre-hydrolyzed soda-AQ dissolving pulp including high α-cellulose content and brightness, and even viscosity is completely feasible through controlling and optimizing the acid pre-hydrolysis, pulping, oxygen delignification stages, and D0ED1 bleaching sequence.
Hamid reza Mehri Iraie; Ali Ghasemian; Hossein Resalati; Ahmad reza Saraeyan; Iman Akbarpour
Abstract
This research was conducted to investigate the bleaching of combined old newspapers (ONP) and old magazines (OMG) deinked pulp using sodium dithionite. The pulp was bleached using 0.5, 0.75, and 1% sodium dithionite and different times of 30, 60 and 90 minutes. The pulps were then refined to 300 ml, ...
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This research was conducted to investigate the bleaching of combined old newspapers (ONP) and old magazines (OMG) deinked pulp using sodium dithionite. The pulp was bleached using 0.5, 0.75, and 1% sodium dithionite and different times of 30, 60 and 90 minutes. The pulps were then refined to 300 ml, CSF freeness and standard handsheets were made from the refined pulps. The optical and mechanical properties of handsheets and the COD of bleaching effluent were measured according to TAPPI standard test methods. The results showed that the brightness of paper was increased significantly with increase in time and sodium dithionite charge. When the charge of bleaching agent increased, the mechanical properties of handsheets and COD load of bleaching effluent were increased and paper bulk and opacity decreased but these changes were not statistically significant. Increasing the bleaching time from 30 to 90 minutes resulted in a significant improvement in tensile, burst and tear indices but the opacity of paper was reduced.
Pulp and paper
Mohammad Molaei; Aliakbar Enayati; Yahya Hamzeh; Maryam Rostaei
Abstract
A fundamental study was carried out to explore the canola stalks properties in order to increase the use of abundant agricultural residuals in pulp and paper production. In this study, the morphological, chemical composition and soda pulping properties of Canola stalks were investigated. The results ...
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A fundamental study was carried out to explore the canola stalks properties in order to increase the use of abundant agricultural residuals in pulp and paper production. In this study, the morphological, chemical composition and soda pulping properties of Canola stalks were investigated. The results showed that except the thicker cell wall, the morphological properties of Canola stalks fibers were comparable to those of nonwoods and hardwoods fibers. Chemical analysis indicated that Canola stalks contains lower amount of cellulose (44%), while the lignin, hemicelluloses and ash content of Canola stalks are comparable to other non-woods. In comparison with most of non wood fiber resources, soda pulping of Canola stalks required higher chemical charge and pulping time. Soda pulping of Canola stalks in 22% active alkaline and 100 min in max temperature produced pulp with 82.6% ISO of brightness The strength properties of bleached Canola stalks soda pulp include tensile index (Nm/g), burst index (kpam2/g) & tear index (mNm2/g) showed respectively 63.6, 2.22 & 4.9.
Pulp and paper
Noraldin Nazarnezhad; Mohammad taghi Asdolahzadeh
Abstract
This study was investigated the effect of Trametes versicolor on chemimechanical pulp (CMP) delignification. CMP were obtained from Mazanderan wood and paper industries. Circle mats were made from CMP (diameter, 7cm; thickness, 1mm) and fortified with 1g/Lit yeast juice. After sterilized, pulp mats were ...
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This study was investigated the effect of Trametes versicolor on chemimechanical pulp (CMP) delignification. CMP were obtained from Mazanderan wood and paper industries. Circle mats were made from CMP (diameter, 7cm; thickness, 1mm) and fortified with 1g/Lit yeast juice. After sterilized, pulp mats were incubated with tow disks punched from mycelium. The duration of incubate were 5, 10, 15 & 20 days as well as temperature and moisture 25oC and 40%, respectively. Standard hand sheets were made from biodelignification pulp, and was measured mechanical and optical properties. The portion of biodelignification pulp was alkaline extracted under condition of pulp consistency, 10%; temperature, 70oC; time, 80min and 2% sodium hydroxide, and then bleached under conditions of pulp consistency, 10%; temperature, 50oC; time, 60min and 4% hydrogen peroxide. Finally, mechanical and optical properties of standard hand sheet were measured. Results showed optimum time was 10 days that decreased 5.9% lignin. Mechanical properties of treated samples were lower than control samples, but statically were not significant. Optical properties of treated samples were lower than control samples but alkaline extraction and then bleaching with sodium peroxide was increase it.
