K. S. Bhandari , Anju Bhatnagar

Abstract

Eucalyptus tereticornis was subjected to kraft pulping using 12, 14, 16, 18% active alkali at 25% sulphidity level. It yielded 44.70, 49.70, 46.40 and 46.00% screened pulps, corresponding to kappa number 56.34, 44.91, 32.69 and 26.46, respectively. The pulps corresponding to kappa number 44.91 and 26.46 were evaluated for strength properties and subjected to oxygen treatment at 6,8,10 kg/cm² oxygen pressure and 90, 100, 110 and 120°C temperature for 60 minutes. 0.00, 1.25,2.50,3.75 and 5.00% alkali was charged during oxygen treatment, in each case. Pulp yield, kappa number and brightness of pulps were determined, in each case and results were analysed. It was observed that at 3.75% and 2.50% alkali charge for pulp corresponding to kappa number 44.91 and 26.46, respectively, the kappa numbers were decreased to 21.32 and 13.05 at 8 kg/cm² oxygen pressure and 60 minutes reaction time. Thus considered to be sufficient to achieve about 50% (about 50% drop in kappa numbers) delignification. Further, the pulps produced at different temperature, 90, 100, 110 and 120°C under optimise conditions of oxygen pressure and alkali charge were evaluated for strength properties. On the basis of the data obtained, 100°C oxygen treatment temperature was found to be optimum. Results are discussed in this paper.

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Anita Srivastava , K. S. Bhandari

Abstract

Sulphite pulping of wet cleaned wheat straw was carried out using 12% Na₂ S0₃ at 160°C for 120 minutes maintaining 1:6 bath ratio. Sulphite spent liquor was collected by squeezing the cooked material. Lignosulphonate was isolated from sulphite spent liquor and subjected to oxidative ammonolysis at 90, 110, 130 and 150°C for 0, 30, 60 and 90 minutes reaction time after attaining the maximum temperature. Each ammonolysed product was analysed for its elemental composition. C/N ratio of each product was computed from these values. It was observed that amount of nitrogen in Lignosulphonate increased with the increase in reaction time and temperature, consequently, the C/N ratio ,.was decreased. However, reaction temperature has more pronounced effect on nitrogen incorporation rather than the reaction time. At 90°C reaction temperature, the improvement in nitrogen content with reaction time was consistent but at slow rate. At 110°C and 130° reaction temperature, nitrogen content was improved sharply up to 30 minute reaction time followed by marginal improvement beyond 30 minutes. It was improved to 3.95 ± 0.23%, 4.29 ± 0.21 % and 4.98 ± 0.04% for 30,60 and 90 minutes reaction time corresponding to 8.35 ± 0.57, 7.64 ± 0.47 and 6.53 ± 0.12 C/N ratio as against 0.00% and 1.82 ± 0.18% nitrogen content for control sample and sample ammonolysed for 0 minute which correspond to - 17.99 ± 2.34 C/N ratio. However, at 150° C reaction temperature, the nitrogen content was sharply increased to 6.98% in 60 minutes reaction time corresponding to C/N ratio 4.19 as against 0.00, 2.48 and 4.87% for control sample and samples ammonolysed for o and 30 minutes which correspond to 13.17 and 6.59 C/N ratio. Beyond 60 minutes, though it was improved to 7.57% corresponding to C/N ratio 3.74 but comparatively at slower rate. The carbon hydrogen and sulphur content were decreased and oxygen content was increased in the initial period of reaction, subsequently it had also shown the decreasing trend as reaction proceeds. Results are discussed in the paper at adequate length.

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Anita Srivastava , K. S. Bhandari

Abstract

Old newsprint were deinked using sodium salts of benzene sulphonic acid (2.00%) and Nirma, a commercial detergent (2.00%) available in open market at the rate of Rs. 18 per kg, alone and with the addition of sodium hydroxide (1.50%) or sodium carbonate (1.50%), separately. Each pulp was bleached using mono stage calcium hypochlorite. Unbleached and bleached pulp field and brightness of the pulps were almost comparable, except marginally higher pulp yield for newsprint deinked with sodium salt of benzene sulphonic acid or commercial detergent, alone. Bleaching of pulps revealed that the highest brightness could be achieved in case of detergent and sodium carbonate deinked pulp, thus the pulp was also bleached by P and H/P bleaching sequence(s). It was observed that P stage bleached pulp possessed better strength properties and higher brightness than pulp bleached using other two bleaching sequences. On blending the pulp with bleached bamboo pulp in different ratio, the strength properties and brightness of the resulting pulp furnish improved consistently, hence a particular blending ratio may be chosen to make a paper of adequate properties desired for the end use.

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Anita Srivastava , K. S. Bhandari

Abstract

Soda lignin from wheat straw was isolated, purified and subjected to oxidative ammonolysis at 150°C, 1.5 Mpa oxygen pressure using 33% ammonia (based on lignin) for 0, 60, 150 minutes with the aim to produce N-modified slow nitrogen releasing fertilizer/soil conditioner. On ammonolysis lignin yielded water soluble and water insoluble fractions. The control and Nmodified lignin samples were analyzed for elemental composition. It was observed that in 60 minutes reaction time 6.83 and 17.24% nitrogen, corresponding to 8.5 and 2.5 C/N ratio could be incorporated in water-insoluble and water-soluble fractions of ammonolysis product and concluded that these products possess acceptable level of nitrogen for its use as slow nitrogen releasing fertilizer/soil conditioner.

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Anita Srivastava , S. N. Dhoundiyal , K. S. Bhandari

Abstract

Short Sequence Deinking (SSD) of office waste, computer waste, magazines and newsprints was carried out using different doses of NaOH, Na₂CO₃ and detergent followed by their bleaching. 2% hypochlorite was used for office and computer waste deinked pulps while deinked pulps from magazines and newsprints were bleached with 1.2% H₂O₂. Strength and optical properties of both the pulps were adequate for newsprint production however, these were comparatively better for pulp produced using Na₂CO₃ as deinking chemical at laboratory scale. Pilot plant trials using sodium hydroxide (1.5%) and sodium silicate (3.0%) as deinking chemicals was carried out at 70°C temperature and 8% consistency in hydrapulper for one hour. Magnesium sulphate (0.50%), chelating agent (0.25%) and hydrogen peroxide (1.0%) were added to pulps and bleached for one hour for further brightening of pulps. Deinked and bleached pulp yield was 85.87% for old mixed waste papers and 79.79% for old magazines and periodicals. Paper possessing adequate strength properties; burst index, 2.51 ± 0.38; tensile 29.85 ± 2.31 and 20.81 ± 2.60 in machine and cross direction and tear index, 1.65 ± 0.31 and 1.95 ± 0.50 in machine and cross directions, respectively, was made on pilot plant. Brightness of deinked and bleached pulp was 70.30 ± 7.25. Strength properties and brightness were higher for pulp produced from magazines and periodicals as compared old mixed papers. Similar was the trend for strength properties and brightness of papers after aging. Runnability of papers on paper machine was satisfactory, in both the cases. Deinking conditions and paper making parameters on pilot plant are discussed in the paper.

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K. S. Bhandari , Y. K. Sharma , Anita Srivastava , D. P. Bhatt

Abstract

Pulping experiments on Eucalyptus tuelicornis and Xylia xylocarpa were undertaken in the present study, Laboratory experiments revealed that destructuring has definite advantages in pulping, Pulps of lower kappa number, coupled with higber pulp yield and lower rejects could be obtained at identical conditions or pulping However, these advantages are more significant in the calie of X. xylocarpa as compared to E. tereticornis. This could be due to higher specific gravity of X. xylocarpa Mixture of (1:1) of destructured chips of E. terelicornis and X. xylocarpa along with control were pulped at optimum conditions, derived from preliminary pulping expriments, (17% active alkali, 25% sulpbidity and about 1100 H. factor). It was observed that the mixture of destructured chips produced pulp having lower rejects, about 2% higher screened pulp yield and 5 points lower kappa number. However the physical strengtb properties of pulp from destructured and control chips were almost the same. A prototype laboratory machine was designed and fabricated for the destructuring of chips.

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Y. K. Sharma , K. S. Bhandari , Anita Srivastava

Abstract

Pinus greggii, P. psudostrobus, P. montezume,& P. taeddi of young age (8-10 years) were pulped using 14%, 16% &18% active alkali, 25% sulphidity at about 1906 H factor to assess pulping and papermaking characterstics. It was observed that kraft pulps of these tropical pine species do not have any appreciable difference in physical strength properties of handsheets. All the pulps produced were in the range of burst index, 4.35 ± 0.75; tensile index, 61.65 ± 9.65; tear index. 7.89 ± 0.74 at freeness 300 ml CSF. Total pulp yield and kappa number decreased with the increase in active alkali charge, as expected Comparatively lower tear index in all the cases could be attributed to the young age of the wood samples, used. However, at burst index 3.0 and tensile index 40.0, the tear index was found to be above 10.0. Slight dlfference in physical strength properties at different chemical charge within the species and among the species was observed. It was observed that their was no appreciable improvement in physical strength properties of unbleached pulps on increasing the alkali charge (at least over 16% alkali charge at freeness 300 ml CSF), except decrease in kappa number, under the conditions studied. Therefore, it could be concluded that for unbleached grade pulps, 16% active alkali would be suitable. However, 18% active Alkali would be more suitable to produce easy bleachable pulps of lower kappa number (⋍ 35). Proximate chemical analysis and fibre dimension analysis have been carried out and recorded in the paper. These have also been correlated with the pulping and papermaking characteristics of individual sample. A comprehensive review on the work done by various workers at this institute on the pulping and papermaklng characteristics of some of the indigenous and exotic pine species have also been included in the paper for comparison.

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Y. K. Sharma , K. S. Bhandari , S. N. Dhoundiyal , Anita Srivastava

Abstract

Samples from young (10-12 years old) Pinus greggii and Pinus pseudostrobus were pulped with 18% active alkali, 25% sulphidity at 1905 H factor in an indirectly heated forced circulation type vertical stationary digester in pilot plant. There was no appreciable difference in screened pulp yield (43.0 ± 1%) and kappa number (38.6 ± 2.0) of unbleached pulps in the two species studied. Unbleached and bleached pulps from both the species were evaluated for their physical strength properties at laboratory scale and MG kraft paper was made at pilot plant. Laboratory evaluation and pilot plant trial revealed that pulps from P. greggii possess better bonding properties than P. pseudostrobus at comparable tearing strength.

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Y. K. Sharma , K. S. Bhandari

Abstract

Pinus greggil, Pinus pseudostrobus, Pinus montezumae and Pinus taeda chips were pulped by thermo-mechancial pulping process to produce pulps suitable for newsprint production. In all the cases the chips were subjected to about 125°C temparature for a period of 3 minutes and refined. In first stage refining a plate clearance of 3.0 mm was kept and refining was done at 17 ± 2% consistency. The pulps were refined in second stage at a plate clearance of 0.15 mm to obtain a freeness of 250 ± 20 ml C.S.F. All the four species of tropical pines produced pulps having satisfactory strength properties. The standard hand sheet properties. In all the cases were almost similar (tear index 2.27 ± 0.2, tensile index 8.5 ± 1.3, opacity 99 ± 0.5 and brightness of unbleached pulps 35.5 ± 1.6% I.S.0.). The results indicated that pulps, in ultra high yield could be prepared, suitable for newsprint production from these tropical pines. The unbleached pulp brightness was, however, lower which could be increased by employing a lignin preserving bleaching method.

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Anita Srivastava , K. S. Bhandari , S. R. D. Guha

Abstract

Holocellulose from Eucalyptus Tereticornis were isolated by 5% potassium hydroxide, 16% potassium hydroxide and 24% potassium hydroxide + 4% boric acid in 14.8%, 84% and 5.3%, yield repectively. The main hemicellulose found to be present was xylan. Holocellulose from Eucalyptus Tereticornis was prepared and subjected to bisulphite pulping (pH 4.5-3.5 and pH 6.5-4.5) and neutral sulphite pH(8.5-6.5). Hemicellulose isolated by 5% potassium hydroxide from the residual holocellulose of sulphite cooks. Physico-chemical changes in henicelluloses were studied. It was observed that with the increase in Ph the retention of hemicellulose in residual holocellulose improved. But contrary to this, isolatable amount of hemicellulose decreased, particularly, xylan. Reasons for the same are discussed in the paper.

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Y. K. Sharma , K. S. Bhandari , Anita Srivastava

Abstract

Crude, ethanol extracted and acid hydrolysed Boswellia serrata resin gums were tested for their internal sizing capability and compared with the conventional internal sizing agent, pine rosin. It was observed that crude resin gum has poorest sizing capability, Ethanol extracted resin gum and acid hydrolysed resin gum are best among these. From series of Laboratory and pilot plant experiments, it was concluded that 1.50% of acid hydrolysed B. serrata resin gum gives equally sized paper as 100% of pine rosin(Cobb 60, 24.0±1.2).

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K. S. Bhandari , Anita Srivastava , Y. K. Sharma

Abstract

High yield pulping of wheat straw was carried out using sodium hydroxide and a mixture of sodium hydroxide + Sodium carbonate as pulping chemicals. Anthraquinone was used as a pulping additive. On the basis of series of experiments, it was observed that pulps with almost similar pbysical strength properties could be obtained by using 2% NaOH + 6% Na₂CO₂, 4% NaOH + 2% Na₂CO₃ and 6% NaOH. However, pulp yield was slightly higher in case of 2% NaOH + 6% Na₂CO₃. From the present study it was concluded that sodium hydroxide could be replaced partially by sodium carbonate without adversely affecting the quality and quantity of pulp produced.

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Anita Srivastava , N. C. Kahera , K. S. Bhandari , Y. K. Sharma

Abstract

Soda pulping of gunny bags, bagasse and Sesbania aegyptlaca were carried out using 8%, 10% and 16% alkali respectively. Each pulp was bleached using two stage calcium hypochlorite with fresh water wash in between two stages. Pulp evaluation of indivIdual pulp and pulp blended in dlfferent ratio were carried out. It was observed that Sesbania aegyptiaca produces superior pulp than the bagasse at almost same bleached pulp yield with higher pluplng chemical. From the blending studies it was concluded that 20 : 60 : 20 or 20 : 40 : 40 blending ratio for gunny bags: bagasse: Sesbania aegyptiaca; 20 : 80 blending ratio for gunny bags: bagasse and gunny bags: Sesbania aegyptiaca yielded better properties.

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Y. K. Sharma , K. S. Bhandari

Abstract

A historical background of pulping of Ecalyptus is reported. Work done in Cellulose and Paper Branch, Forest Research Institute on various species of Eucalyptus by various pulping processes is discussed and results are recorded in the paper.

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K. S. Bhandari , S. S. Bhandari , S. V. Singh

Abstract

Kraft pulps from Acacia rodusta (9 year) and Acacia mellifera (4 year) were produced with 16% Active alkali at 25% sulphidity with pulp yield of 52.23% and 51.16% respectively. The pulps obtained could be bleached with C/E/H/H sequence to a brightness (Elrepho) of 70.62 and 68.0 respectively, the bleached pulp yield being 49.5% and 48.67%, respectively. The bleached kraft pulps obtained from both the species possessed almost similar physical strength properties. The investigations indicate that bleached kraft pulps from Acacia robusta and Acacia mellifera could he used satisfactorily for paper making with the addition of some long fibred pulp.

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K. S. Bhandari , Anita Srivastava , Y. K. Sharma

Abstract

Soda and Soda-Anthrequinone (AQ) pulping of wheat straw were carried out with an aim ie produce pulps for writing and printing papers with fairly good brightness. 11.75,%. active alkali (without AQ) and 10% active alkali (with AQ) produced a pulp of Kappa number 25 ± 1 at 1665 'H' factor with almost identical physico-chemical properties. A gain of 1.8% pulp yield was also observed in latter case. Pulps thus obtained (with and without AQ) have shown almost similar bleaching response. When bleached by C/E/H (5% available chlorine, 2% NaOH extraction/2.5% available chlorine) upto brightness of elrepho 72.9% ± 0.5. Kraft-AQ pulping (8% active alkali, 8.5% sulphidity) has also been carried out. Under the experimental conditions it was obseryed that the presence of hydrosulphide ion (sulphidity 8.5%) in cooking liquor have shown only slight advantage over soda pulps at same level of active alkali.

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K. S. Bhandari , Anita Srivastava , S. P. Singh , Y. K. Sharma

Abstract

Soda, Soda-anthraquinone (AQ) (both at 16% active alkali, approx. 1115, H factor) and Kraft (l4% active alkali, approx. 810, H factor, 25% sulphidity) pulpings were carried out to compare the yield, degree of delignification and physical strength properties of unbleached pulps, It was observed that soda. AQ pulp was slightly better than the controlled soda pulp but was inferior to the kraft pulp in respect to its quality and yield.

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