Informatics Publishing Limited

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

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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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Sushma Mahajan , A. K. Raj , S. P. Singh , S. N. Dhoundiyal , Y. K. Sharma , S. V. Singh

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The present paper gives a comparative account of basic density and kraft pulping characteristics of fourteen species of Barataung area and eighteen species of Middle Andman area of Andaman&Nicobar Islands. The properties of kraft pulps of individual species have also been evaluated. It has been found that the basic density varied widely with species in both areas. In Barstaung area the variation was from 0.302 to 0.847 g/cm², whereas for Middle Andaman gives area it was in between 0.261 to 0.728 g/cm². Laboratory experiments on kraft pulping of individual species have shown that most of them gave screened pulp in the range of 40-45% yield, the only exception being Mitraeyna retundifolia of Barataung area and Knema sp of Middle Andaman area which gave pulp yield below 40%. The physical strength properties of unbleached kraft pulps of all the species were found to be adequate for wrapping grade paper. Pilot plant trials have shown that the mixed species of both areas could be pulped wlth 18% active alkali (as Na₂O) to produce unbleached kraft pulps of about 45% of yield. The paper made from these unbleached kraft pulps on pilot paper machine was of satisfactory strength for use as wrapping paper. It was further established that these pulps could be bleached to 75 brightness by conventional C/E/H/H/ sequence to produce writing and printing paper.

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Y. K. Sharma , G. M. Mathur , Om Bahadur , S. N. Dhoundiyal

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Plantations of different species of tropical pines have raised all over the country. Tropical pines can be a good raw material resource for the much wanted newsprint grade printing paper. In this paper, results on pulping of Pinus patula grown in Uttar Pradesh, by sulphate, chemi-mechanical and refiner mechanical processes have been recorded. Results show that suitable pulps in good yield can be produced by these processes. Blending studies of these three type of pulps further revealed that newsprint grade paper can be produced from Pinus potula.

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Y. K. Sharma , S. N. Dhoundiyal , G. M. Mathur

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S. R. D. Guha , Y. K. Sharma , S. N. Dhoundiyal

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The paper reports The results on soda pulping of Hibisucus subdariffa Linn (Roselle), The average fibre length of bast fibre was 305 mm, fibre diameter-21.91 μ and cell wall thickness 5.6 μ The woody portion had an average fibre length of 0.799 mm, fibre diameter of 32.1 μ. And cell wall thickneso of 2.9 μ. Soda pulps in good yield and satisfactory properties could be prepared in laboratory. Pilot Plant scale trial confirmed laboratory finding. Pulping of bast fibre along, woody portion and whole plant indicated that yield of bast portion and woody portion was more or less same. The strength properties of bast pulp were higher.

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S. R. D. Guha , S. N. Dhoundiyal , G. M. Mathur , Y. K. Sharma

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S. R. D. Guha , S. N. Dhoundiyal , Prem Nath , G. M. Mathur , Y. K. Sharma

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S. R. D. Guha , S. N. Dhoundiyal , G. M. Mathur

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S. R. D. Guha , Man Mohan Singh , G. M. Mathur , Y. K. Sharma , S. P. Singh , S. N. Dhoundiyal

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Proximate chemical analysis and fibre dimension of Cupressus cashmeriana have been recorded. Sulphate pulps, suitable for kraft paper have been prepared on a laboratory scale. Laboratory as well as pilot plant experiments for the production of writing and printing paper as well as newsprint grade paper have shown that these grades of paper can also be manufactured from Cupressus cashmeriana.

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S. R. D. Guha , G. M. Mathur , Y. K. Sharma , S. N. Dhoundiyal , J. B. Lad , S. C. Desai

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The paper gives the results of the work done on mixture of hardwoods of three different regions, Chanda, Ballarshah and North Dhulia of Maharashtra State. The results show that the chemical pulps can be made from these mixtures for writing, printing and wrapping papers.

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S. R. D. Guha , S. N. Dhoundiyal , J. P. Joshi , G. M. Mathur , Y. K. Sharma

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S. R. D. Guha , S. N. Dhoundiyal , G. M. Mathur , Y. K. Sharma

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Laboratory and pilot plant scale trials on the production of writing paper from a mixture of grasses from Andbra Pradesb are described. The results indicate that the mixture requires some admixture of long fibre for smooth running of the machine.

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S. R. D. Guha , S. N. Dhoundiyal , Jainagesh A. Sekhar

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The paper reports results of an investigation on tbe suitability of Mikaina micrantha for papermaking. Chemical pulps were obtained only in low yields and with low strength properties.

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S. R. D. Guha , S. N. Dhoundiyal , G. M. Mathur

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Bamboo is the main source of fibrous raw material for pulp and paper industry. Various species of bamboo are being used for this purpose. The main species used is Dendrocalamus strictus. The Forest Botanist, Forest Research Institute suggested that Dendrocalamus giganteus (I) which is the largest of bamboos should also be tested as this species of bamboo has not so far been used for the production of paper. The results of a comparative laboratory scale investigation or Dendrocalamus giganteus and D. strictus are recorded in this paper.

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