R. V. Bhat , K. C. Virmani

Abstract

No abstract

Full Text

     

R. V. Bhat , K. C. Virmani

Abstract

Laboratory experiments on the production of chemical pulps by the soda and sulphate processes from Phragmites karka, Trin. ( nal ) are described. The results of pilot plant experiments on the production of chemical pulps and writing and printing papers are included. Since this species of grass grows in habitats where another similar species Arundo donax, Linn., is found, a digestion on a pilot plant scale of a mixture of these two grasses was carried out with satisfactory results. Samples of paper made from Phragmites karka and from the pulp obtained by digesting the mixture of this species and Arundo donax are inserted in this bulletin. The pulps from Phragmites karka are short-fibred and hence the admixture of these pulps with longfibred pulps such as those of sabai grass (Eulaliopsis binata) or bamboo is essential for the successful use of this reed for the production of paper on a commercial paper machine. It is reported that this species is found in large quantities in Assam. Since transportation of this reed-like grass to places outside Assam at an economic price is not possible, attention must be directed to the establishment of a paper mill in Assam utilizing this species. Bamboo is also available in Assam for the production of chemical pulp for admixing with the short-fibred pulp of Phragmites karka for the manufacture of paper.

Full Text

     

K. C. Virmani

Abstract

Laboratory experiments on the production of mechanical pulps from Sterculia campanulata (papita) are described. Standard pulp sheets were prepared from 100% mechanical pulp from this species and from a mixture of 70% mechanical pulp and 30% bamboo bleached chemical pulp. The strength properties of the standard sheets prepared from the mechanical pulp produced under suitable conditions have shown that this wood is a promising raw material for the production of newsprint. The colour of the pulp is also suitable for newsprint. This species is available in the Andamans and the wood is used in the match industry in Calcutta.

Full Text

     

R. V. Bhat , K. C. Virmani

Abstract

Laboratory experiments on the Sulphate digestion of the wood of Sterculia campanulata, Wall. (papita) are described. The bleached chemical pulps were characterized by high strength properties. The average fibre length of the chemical pulp was 1.49 mm. The results of the pilot plant experiments on the production of chemical pulps and writing and printing papers are included. This investigation has indicated that this wood is a suitable raw material for the production of writing and printing papers. A sample of writing paper made entirely from S. campanulata pulp and another of printing paper made from a mixture of 68% S. campanulata pulp and 32% bamboo pulp are appended.

Full Text

     

R. V. Bhat , K. C. Virmani

Abstract

Laboratory experiments on the production of chemical pulps by the sulphate process from wattle woods (Acacia decurrens and Acacia mollissima, Willd.) are described. Results of five pilot plant experiments on the production of chemical pulps and writing and printing papers are also included. In the case of three pilot plant experiments, a mixture of equal quantities of the two species of wattle wood was used for the digestion. These wattle woods are short-fibred and, hence, admixture of their pulps with about 40% of a long-fibred pulp such as bamboo pulp is necessary for making paper. Papers made from mixtures of wattle and bamboo pulps prepared under suitable conditions had good formation and satisfactory strength properties. Three samples of papers are appended. One sample is from A. decurrens, another from A. mollissima and the third from a mixture of the woods of the two species.

Full Text

     

R. V. Bhat , K. C. Virmani

Abstract

In India, bagasse (crushed sugarcane) is produced to the extent of over 1.5 million tons (on the bone-dry basis) in sugar mills. It is mostly used for burning in boilers for raising steam in the sugar mills themselves. This cellulosic material is used to some extent for the production of various kinds of papers in some parts of the world growing sugarcane. Intensive research work carried out in foreign countries prior to 1938 led to the conclusion that it is essential to remove pith from bagasse if this fibrous material is to be used for the manufacture of good quality writing and printing papers. Processes used in foreign countries for the manufacture of pulp from bagasse require special patented machinery and licence of the inventors for their use by others. With a view to developing a process suitable to Indian conditions, an investigation was undertaken at this Institute on the separation of pith from bagasse and making writing and printing papers from the depithed material. Laboratory and pilot plant experiments gave encouraging results. A successful commercial run was carried out in Shree Gopal Paper Mills Ltd., Jamuna Nagar (Punjab), using 70% of bagasse pulp and 30% of bamboo pulp. This paper was used for printing a dak edition of The Statesman, New Delhi. Papers were also made on the pilot plant from mixtures of bagasse pulp with sabai grass and ulla grass (Themeda arundinacea) pulps and by adding bagasse pith to the bagasse pulp. Samples of all these papers are appended in this bulletin. A sheet of the The Statesman printed on the bagasse-bamboo paper is also appended.

Full Text

     

R. V. Brat , K. C. Virmani

Abstract

Experiments on the preparation of ground wood pulps from blue gum (Eucalyptus glabulus Labill.) and waattle wood (Acacia decurrens Willd.) under various conditions of grinding are described. Newsprint was prepared on the pilot plant paper machine of this Institute from a furnish containing 76% of blue gum groundwood pulp ( bleached) and 24% of bamboo sUlphate pulp (bleached). A sample of the newsprint is appended. Newsprint was also made on the pilot plant from a mixture of 75% of wattle groundwood pulp ( bleached) and 25% of bamboo Sulphate pulp (bleached). A sample of this newsprint is also appended.

Full Text

     

R. V. Bhat , S. R. D. Guha , K. C. Virmani

Abstract

Laboratory experiments on the production of mechanical pulps from Abies pindrow (Silver fir) are described. Standard pulp sheets were made from 100 per cent mechanical pulp from this species and from a mixture of 70 per cent mechanical pulp and 30 per cent bleached bamboo chemical pulp. Strength properties of the standard sheets prepared from the mechanical pulp produced under suitable conditions have shown that this wood is a suitable raw material for the production of newsprint.

Full Text