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Paper Engineering Senior Theses Chemical and Paper Engineering
6-1960
Cold Caustic Soda Pulping of Eucalyptus Saligna
Tachipully A. Bhaskaran Western Michigan University
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Recommended Citation Bhaskaran, Tachipully A., "Cold Caustic Soda Pulping of Eucalyptus Saligna" (1960). Paper Engineering Senior Theses. 85. https://scholarworks.wmich.edu/engineer-senior-theses/85
This Dissertation/Thesis is brought to you for free and open access by the Chemical and Paper Engineering at ScholarWorks at WMU. It has been accepted for inclusion in Paper Engineering Senior Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact wmu- [email protected]. COLD CAUSTIC SODA PULPING OF
EUCALYPTUS SALIGNA (
SENIOR STUDENT THESIS
PRODUCED IN PARTIAL FULFILLMENT OF
REQUIREMENTS FOR THE DEGREE OF BACHELOR OF SCIENCE IN PAPER TECHNOLOGY
BY
TACHIPULLY A. BHASKARAN
DEPARTMENT OF PAPER TECHNOLOGY
SCHOOL OF APPLIED ARTS AND SCIENCES
WESTERN MICHIGAN UNIVERSITY
KALAMAZOO, MICHIGAN JUN, 1960 T.A.B.
COLD CAUSTIC SODA PULPING OF EUCALYPTUS SALIGNA
TABLE OF CONTENTS
1. Summary------la
2. A Brief Description of the Genus Eucalyptus------1
3. The Species Eucalyptus saligna------2
4. Pulping of Eucalyptus saligna by Various Processes----- 3
5. Cold Caustic Soda Pulping of Eucalyptus Species------7
6. Conclusions of Literature Survey------10
7. Literature Cited------11
8. Experimental Design------13
9. Experimental Work------14
10. Discussion of Results------17
11. Conclusions------19
WESTERN MICHIGAN Ut-' 1 V'" PS'TY L'BRARY KALAMAZOU, i-.lC; 1.1..:, ,. �-vvl T.A.B. -la-
COLD CAUSTIC SDDA PULPING OF EUCALYPTUS SALIGNA
SUl1MARY
A survey has been prepared covering the literature on the cold caustic soda pulping of Eucalyptus saligna. The survey was broadened to include pulping of all species of Eucalyptus by this particular process.
Experimental pulping of •'ucalyptus saligna by the cold caustic soda process under a variety of conditions as well as pulping of aspen wood under one condition led to the following conclusions:
(a) Eucalyptus saligna is suitable for the manufacture of cold caustic soda pulp.
(b) Alkali concentration of 30 grams per liter on full size chips of
Eucalyptus saligna produces the best strength properties and fairly good yield.
(c) The use of crushed chips is not advisable at higher alkali concentrations since a loss of strength results. Where low alkali concentrations are used, the crushing of chips improves liquor penetration with a reduction in the quantity of screen rejects.
(d) In no case did the Eucalyptus pulps reach the strength of aspen pulp under the conditions of the experiment. T.A.B.
I. A Brief Description of the Genus Eucalyptus.
Eucalyptus is a large genus of trees of the family of Myrtaceae and is indigenous, with a few exceptions, to Australia and Tasmania.
The ecualypti are rapid in growth. Many species of this genus attain great height, Eucalyptus amygdalina, the tallest known tree, growing as much as 480 ft.
An essential oil is obtained by aqueous distillation of the leaves of this and other species of eucalyptus. This oil consists of many different substances, the most important of which is eucalyptol, a volatile oil, which represents about 70% of the total.
As is well known, eucalypti are the chief species used in pulp and paper making in Australia. There are 400 species of eucalypti, but less than twenty are used in the manufacture of pulp and paper in Australia (11).
Experiments to ascertain their utility for pulp and paper manufacture began there as early as 1920. However, it was not until 1938 that the first commercial production of eucalyptus pulp began. Today about seventeen species are used for pulping in different parts of the Commonwealth (18).
Eucalypti thrive well in sub-tropical areas but they will also grow in cold and tropical climates. However, eucalyptus is exigent about the physical conditions and less demanding about the chemical conditions of the soil on account of the tap roots of the tree which need a highly permeable soil (17).
Since 1854, Eucalyptus has been successfully introduced into the South
of Europe, Algeria, Egypt, Tahiti, California, South America, South Africa, T .A.B. -2-
India and other countries which have suitable climatic and soil conditions for its successful growth.
Eucalyptus was first brought to Brazil by the Jesuits in 1800, but it was the Companlria Paulista de Estradas de Ferro which was chiefly responsible to introduce the economic planting of the eucalyptus in the State of Sao
Paulo and in other parts of Brazil. The progress has been so rapid that there exists over 40 million eucalypti in Brazil today. It is believed that Latin
America has no other source so abundant and valuable as eucalypti for meeting the needs of the pulp and paper industry (17).
Eucalyptus fibers are only about one millimeter long but they are very narrow and can be made into a very strong sheet depending on pulping conditions.
E. delegatensis, E. dalrympleana, E. oreodes and similar types have fibers with thin walls which are flexible and up to 1.5 nnn long. The diameter is between 15-30 microns. The wood has a cellulose content of 50% (1).
II. A Brief Description of E. saligna.
E. saligna is a native of the semi-tropical regions of New South Wales and Southern Queensland, where it is known as Sydney Blue Gum.
It thrives well in sub-tropical and moist mountain areas of South Africa where the trees are now about 40 years old; 10,000 acres have been planted with this species by the Department of Forestry, Union of South Africa. The tree grows very rapidly and adds eight feet in height and one inch in diameter each year (7). T .A.B. -3-
Large areas have been planted with Eucalyptus saligna in Zul.uland, and
Northeastern Transvaal and it has been successfully introduced into Uganda,
Kenya, Tanganyka and recently into Nigeria (20). In Latin America one of the species chiefly available is E. saligna. The selection of this species has proved extremely satisfactory in this region (16).
E. saligna grows up to a height of 100 ft.; the circumference of the trunk increases to 26 ft. (3). The Forestry Service in Brazil has established that of all the eucalypti planted there, Eucalypti saligna and grandis gave the best pulp yields. These woods are of medium density and of sufficiently light color to make bleaching easy; they can supply as good a pulp as the best employed in Australia. Trees, eight years of age, gave the best results for pulping (17).
III. Pulping of Eucalyptus saligna by Various Processes.
III.-A. Early Investigations on Chemical Pulping.
The technical literature contains a few publications dealing with the pulping of E. saligna by kraft, soda, sulphite and neutral sulphite semichemical processes, even as early as 1927.
Navarro (12) in his pulping studies of E. saligna and eucalypti species by the sulphite and kraft processes, carried out at the Forest Products Laboratory,
Madison, stated that some of his experimentls were unsuccessful. However, the best results were reached when E. saligna was pulped to a yield of 47.6%.
The age of the tree was 15 years. The investigation also reported that if T.A.B. -4-
the woods were much older, the fibers become plump and the ability to form up properly in papermaking is diminished. The fibers of the younger woods produced a sheet with a formation similar to that of strawpulp. Navarro made fiber measurements of the E. saligna pulp and established that it had an average length of 0.90 mm. A chemical analysis of the wood gave the following results:
Hot water solubility 3.52% 1% NaOH solubility 17.43% Lignin 33.01% Cellulose 54.75% Pen tosans 16.50%
The breaking length of the paper was 4985 m.
Other anonymous investigators (2) pulped six year old E. saligna from
Zululand by the soda process using 20% sodium hydroxide at a temperature of
160°c for five hours. The results of the experiments showed that a well digested pulp with a yield of 55% could be obtained. The dimensions of the fibers were between 0.8 - 2.1 mm (average 1.4 nun) in length and between
0.0102 - 0.033 mm (average 0.0163) in diameter. The pulp produced a fairly soft, opaque and pale brown paper of good strength but the pulp appeared slightly shivy due to the knotty nature of the wood. Bleaching of this pulp with 20% bleaching powder (on the original weight of wood), gave a yield of
42% (on the original wood). The bleached pulp had the following composition:
Ash 0.33% Alpha cellulose 85.00% Beta cellulose 10.02% Gamma cellulose 4.80% Copper number 2.04% Phloroglucinol absorption 1.60% T.A.B. -5-
Soda absorption value 2.09% Ace tone extract 0.46%
Both bleached and unbleached pulps produced papers of similar strength and character.
III.-B. Recent Investigations on Chemical Pulping.
Chittenden, Coomber and Corney (7) pulped E. saligna of about seven years of age from South Africa by the soda and sulphite processes in the laboratories of the Imperial Institute in 1948. The pulping of the wood by the soda process under mild conditions produced a well digested pulp with a fairly good yield. Handsheets made from the pulp indicated good formation but owing to the short fiber nature of the pulp, the paper had low strength properties.
Sulphite digestion of this wood under average conditions resulted in satisfactory yields. However, a small amount of the pulp was improperly cooked. The pulp had also poor strength properties. All the pulps responded readily to beating. A chemical analysis of the sawdust gave the following results expressed on the moisture free material:
Ash 0.7% Resin (including waxes and fats) 13.0% Alkali solubility (1% NaOH for 1 hr. at 100°c) 13.2% Cellulose 54.9%
A microscopical examination of the fibers showed the following results:
Max. Min. Average Length in IIUn 1.4 0.6 1.0 Diameter in microns 32 12 19
The results, therefore, indicated that the wood had a fairly high cellulose content and a satisfactory low alkali solubility whereas, the resin content was high. T.A.B. -6-
Chidester and Schafer (8) of the Forest Products Laboratory, Madison, carried out sulphite and sulphate digestions of E. saligna. The sulphite pulping trials indicated that satisfactory chemical pulps could be produced which were suitable for blending with groundwood pulp for the manufacture of newsprint and similar papers. Kraft cooks of E. saligna using 15.6% active alkali as sodium oxide based on the wood,produced a slightly stronger pulp than sulphite cookso A yield of 48% was reported for the kraft pulp.
Jayme and Branscheid (10) carried out mild sulphite digestions of E. saligna and concluded that the wood gave very strong pulps. The maximum
° ° cooking temperature was 120 c - 125 c for a maximum total period of nine hours (six hours at maximum temperature). The cook produced an average yield of 57% and the amount of screens was low. The pulps were mechan:ically refined
° very readily and at 65 - 70 Schopper-Riegler, had strength properties comparable to those of spruce sulphite pulps. The investigation also revealed that under optimum conditions, the unbleached pulp had a breaking length of
9450 m, a tearing resistance of 145.5 cm-g/cm, a bursting strength about
5 kg/sq. cm., and a folding endurance of over 3000 double folds. In concluding, the authors stated that a paper of high strength properties could be made from this pulp without the addition of long-fibered cellulosic materials.
III.-C. Recent Investigations on Semichemical Pulping.
Carvalho (6) carried out pulping experiments of E. saligna from Brazil by the neutral sulphite and kraft processes. The neutral sulphite digestion
was carried out by treating the chips with 19.7% sodium sulphite expressed T.A.B. -7-
as sodium oxide (on the basis of dry wood), at a temperature of 175°C for
four hours. The resultant pulp had a permanganate number of 39.2 and a yield of 57%. Pulping the wood by the kraft process, with 14.83% sodium hydroxide and 29.5% sodium sulphide (expressed as sodium oxide on a dry wood basis), gave a permanganate number of 11.9.Carvalho claimed that the eucalyptus kraft pulp had greater strength properties than imported spruce sulphite.
Francesco and Ceregiolo (14), pulping E. saligna by the neutral sulphite
semichemical process, stated that pulp similar to poplar semichemical and
superior to beech and chestnut semichemical could be produced.
III.-D. Conmercial Production of Pulp from E. saligna.
In spite of the abundant resources of this species in Brazil, South
Africa and in other countries, only small scale cormnercial production of
pulp and paper from this wood has been undertaken. A mill in Jundiai,
Brazil, manufactures soda pulp from E. saligna and uses 25% imported chemical
pulp in the furnish. Another mill at Caseras, Sao Paulo, produces 30 tons
of writing, printing and toilet paper from 75% E. saligna and 25% conifer
pulp (17).
IV. Cold Caustic Soda Pulping of Eucalyptus Species.
IV.-A. The Cold Caustic Soda Pulping Process.
The cold soda pulping process for wood chips was developed at the Forest
Products Laboratory, Madison. Reports were first published in 1951. T.A.B. -8-
Cold soda pulps are produced predominatly from hardwoods by a mechano chemical process. Pulps of high yields in the range of 88 - 90% are obtained.
The cold caustic soda process differs from other methods in that the impregnation of chips is done generally at room temperature.
Penetration is an important variable and depends on the co ncentration of caustic soda and the time of treatment. Penetration of the liquor into the chips is achieved either at atmospheric or at elevated pressure.
The concentration of caustic soda in the liquor is varied between 20 and 75 grams per liter, depending on the properties of the raw material
or the type of pulp to be produced. The soaking period in caustic soda
solution is between two or three hours and is followed by a fiberizing
stage as in all semichemical processes.
Very little is known about the chemical mechanism of the pulping process.
It is beliaved that caustic soda attacks the fiber bonds by reaction with the
acetyl and other acid groups which are reactive even at room temperature,
thereby tending to disrupt the fiber bond (13).
IV.-B. Cold Caustic Soda Pulping of Eucalyptus saligna.
Considerable work on cold soda pulping of E. saligna has been sponsored
by Parsons and Whitemore, New York, since 1955 but nothing pertaining to
this work has yet been published. It was also stated that an active project
for the construction of a cold soda newsprint mill is under way (15) using
E. saligna as the raw material.
Chidester and Schafer (8) reported that cold soda pulping experiments T.A.B. -9-
were made on a mixture containing 25% each by weight of E. saligna, E. tereticornis, E. alba and E. kertoniana. The chips were steeped in caustic soda solution having a concentration of 75 g/1 and the ratio of steeping liquor to wood was 35%. The soaking period was for about two hours at atmospheric pressure. After the soaking period, the chips were fiberized.
The yield of pulp obtained was about 90 percent.
The pulp was semi-bleached with 15% of chlorine as calcium hypochlorite in a single stage to a brightness of about 70 percent. News-type paper was made entirely from this pulp and was comparable to standard newsprint, although the opacity and oil penetration were low (8).
IV.-C. Cold Caustic Soda Pulping of Other Eucalyptus Species.
Somerville and Pearson (19) pulped old and regrowth trees of E. regnans,
E. obliquas and E. gigantea by the cold soda process in the laboratory and on mill scale trials. Their investigations led them to believe that the pulps from chips in the green state gave the same strength as that from air-dried chips. Higher soaking temperatures about 60°c produced stronger but duller pulpi. Freeness had a definite influence on the strength properties of the pulp. At reduced freeness, the burst factor, tear factor, breaking length, drainage time and wet tensile strength increased while bulk decreased.
Bhat and Gupta (4) in their cold soda pulping of E. globulus at room temperature using 25,50 and 75 grams per liter of caustic soda for periods of 2,4,8 and 24 hours produced pulps suitable for the production of cheap grades of writing and printing papers, especially when these were blended -I with long-fibered pulps such as bamboo. Yields of pulps obtained were between
80 - 83%. T.A.B. -10-
Bugg and Pearson (5) stated that the cold soda pulp from E. regnans had much higher strength properties in burst and tear factors than groundwood pulp from the same tree. The cold soda pulp had higher freeness than groundwood pulp and the energy consumed was just halt of that needed for grinding of mechanical pulp.
The study also disclosed that the addition of 20% cold soda pulp to the newsprint furnish made possible an increase of 100 ft. per minute of running speed on the paper machine, resulting in an annual increase in production of over 2,000 tons of newsprint (5).
V. Conclusion.
This literature survey, pertaining to pulping of eucalyptus and E. saligna in particular, has shown that, in the opinion of several workers,
E. saligna is an excellent raw material for the manufacture of pulp and paper.
In countries like Brazil, and parts of Africa, where E. saligna is planted on a large scale, this tree could be a valuable source of raw material for pulp and paper in the near future. T.A.B. -11-
LITERATURE CITED
1. Anon, 11Eucalypts for Paper Manufacture in Australia", Wochbl Papierfabr, 62, No. 13: 306-307 (March 28, 1931). In German.
2. Anon, "Eucalyptus saligna as a Source of Wood Pulp for Paper and Artificial Silk", Bull. Imp. In_!,t. 27, No. 4: 449-452 (1929), T. S. 91: 185, C.A. 24: 1502, .Abstracted from C.A. 3. Anon, "Eucalyptus", Wochbl Papierfabr, 81, No. 22: 824-5 (Nov. 30, 1953). In German.
4. Bhat, R.V., and Gupta, P. R., "Cold Caustic Soda Pulps and Cheap Grade Writing and Printing Papers from Blue Gum (E. globulus)", Forest Research Institute, Dehra Dun, Indian Leaflet No. 211: llp (1956), c. A. 51: 4706. Abstracted from C. A.
5. Bugg, E. J., and Pearson, A. J., "Manufacture of Cold Soda Pulp from Eucalypt Wood", Paper Trade Journal, Yol. 142, Dec. 22, 1958.
6. Carvalho, J.S., "Cellulose Pulp from E. saligna", Anais assoc. brasil quirn. 13: 19-24 (1954), published in 1957, C. A. 52: 722, B.I.P.C. 29: 281, Abstracted from B. I. P. C.
7. Chittenden, A. E., Coomber, H. E., and Corney, N. S., 11E. saligna Wood from s. Africa", Colonial Plant and Anirnial Products, 1, No. 4: 299-308 (1950), Worlds Paper Trade Review, 136 No. 10: 656-668 (Sept. 6, 1951).
8. Chidester, G. H., and Schafer, E. R., "Pulping of Latin American Woods", Pulp and Paper Prospects in Latin America, Second Part, Report of the Latin American Meeting of Experts on the Pulp and Paper Industry. FAQ United Nations, New York (1955), p. 169. • 9. Holmgren, H., Vay, F., Rub, J., and Capo, A. "Cellulose Production from E. saligna by the Sulphate Processn, In the 4th Meeting of the Technical Committee on Wood Chemistry Food and Agricultural Organization of the United Nations. Brussels, August, 1949.
10. Jayme, George and Branscheid, Friedrich, "High Strength Sulphite Pulps from Eucalyptus saligna", Das Papier 13, No. 13/14: 284-6 (July 1959). Ger.; Eng. and Fr. Sum).
11. Jeffreys, R. G., "Pulp and Paper Making from Eucalyptus in Australia", Paper Trade Review 142 No. 22: 1825 (Nov. 25, 1954).
12. Kiefer, Otto, "Paper from the Eucalyptus; Developments in Brazil", Wochbl Papierfabr 58, No. 5: 127-129, (Feb. 5, 1927). In German. T .A.B. -12-.
LITERATURE CITED (continued)
0 13. McGovern, J. N., "College Text Book of Pulp and Paper Manufacture , Chapter XI, page 12, TAPPI, 1958.
14. Francesco, Pancirolli and Ceragiole, Giorgio, "Semichemical Pulps from E. saligna, Cellulose e carta 5 No. 3: 8-12 (1�54), c. A. 48: 14193, Abstracted from C. A.
15. Parsons and Whitemore, New York, Private communication, Nov. 6, 1959.
16. Pulp and Paper Prospects in Latin America (First part), "Pulp and Paper Manufacture from Eucalypts". Report of the Latin .American Meeting of Experts on the Pulp and Paper Industry. FAO United Nations, New York, 1955 p. 18.
17. Pulp and Paper Prospects in Latin America (Second part p. 220). "The Cultivation of Eucalypts in the State of Sao Paulo", Report of the Latin America Meeting of Experts on the Pulp and Paper Industry. FAO United Nations, New York, 1955.
18. Pulp and Paper Prospects in Latin .America "Aspects of Pulp and Paper Manufacture Based on other Latin American Forest Resources". The Secretariat p. 214.
0 19. Somerville, J. L., and Pearson, A. J., Application of Cold Soda Process to use of Eucalypts for Newsprint". Paper Trade Journal Vol. 142, Dec. 22, 1958.
20. nTropical Woods as a Source of Pulp", Symposium Under the Auspicies of the FAO Technical Committee on Wood Chemistry of the United Nations Food and Agricultural Organization, reprinted from Tappi, Vol. 35, No. 4, April 1952, page 163. T.A.B. -13-
Experimental Design
Objective of the Project:
The purpose of this investigation was to ascertain whether suitable cold caustic soda pulps could be prepared from Eucalyptus. saligna.
Experimental Procedure Planned for this Study:
It was planned to carry out cold caustic soda pulping of this wood, using full size and crushed chips. The two pulping variables to be studied will be the effect of alkali concentration and the type of chips viz., full size or crushed. The concentrations of the caustic liquor to be used will be 15, 30 and 60 grams per liter. The steeping of the chips in the caustic liquor at various concentrations will be done at room temperature and atmospheric pressure. The period of soaking of chips will be two hours in all cases.
At the end of the steeping period the residual alkali in the liquor will be estimated. The chips will then be fiberized in a single disk refiner.
The yields of refined and screened pulps will be determined. The strength of the pulps will be evaluated by the beater method according to
TAPPI standard procedure. The freeness of the pulps a,t various times of beating will be recorded.
In addition, it was planned to pulp aspen chip� using the best conditions obtained from cold caustic soda pulping of Eucalyptus saligna for a comparative study. T • .A.B. -14-
Experimental Work
Raw Material, Method and bquipment Used
I. Wood:
The wood chips of Eucalyptus saligna ·were obtained from the U. S.
Forest Products Laboratory, Madison, Wisconsin. The_ length of full size chips ranged from one-half to three-quarters of an inch. The crushed chips for the experiments were obtained by passing the full size chips of Eucalyptus saligna through a Bauer refiner using devil-tooth plates, pattern #6995 at a clearance of 0.150 inch. The diameter of the crushed chips was about 0.25 inch. The aspen chips which were used in the experiment were obtained from the Department of Paper Technology, �estern Michigan University, Kalamazoo,
Michigan, and were from one-half to three-quarters of an inch in length.
II. Preparation of Cold Caustic Soda Pulps
Seven pulping experiments were done. Six of these were carried out with Eucalyptus saligna and one using aspen full size chips. Full size chips of Eucalyptus saligna were used in experiments I, II and VII and crushed chips were used in experiments III, IV and V.
Pulping Procedure:
In all experiments the two variables studied were the effect of alkali concentration and the condition of chips whether full size or crushed. The other variables viz., time of impregnation two hours, temperature 23°C, and liquor to wood ratio 5:1, were kept constant.
For each experiment an equivalent amount of 500 grams of oven-dry chips was weighed out and placed in a plastic bucket. The various amounts of alkali T.A.B. -15-
were then added separately to the weighed chips to obtain an alkali concentration ranging from 15 grams per liter to 60 grams per liter. pH of Liquor:
The pH of the liquor was determined at the start and end of the steeping period by means of a Beckman pH meter equipped with a glass electrode.
Residual Alkali:
After the impregnation period the excess liquor was separated by filtration and 10 ml of this liquor was titrated against standard hydrochloric acid, and the amount of residual alkali was calculated.
Refining:
With the excess liquor removed, the chips after steeping Wei': refined repeatedly in a single disk Bauer refiner using for the first pass 0.005 inch and for the second and third passes 0.002 inch clearance.
Screening of Refined Pulps:
The refined pulps were screened through a ten-cut flat screen. The screen rejects in experiments I, IV and VII were further refined for one more pass at 0.002 inch clearance and again screened in.order to get enough pulp for beater evaluation.
Yield:
After screening, the yields of the screened pulp and rejects were determined. T.A.B. -16-
III. Evaluation of Pulps for Strength Properties by the Standard Beater Method: (T 200 M-45)
For the strength evaluation by the beater method 360 grams of oven-dry screened pulp was used except in experiment I where unscreened pulp was used.
The screened pulp and screen rejects were blended in the desired quantities so as to obtain sufficient pulp for the test.
Beating Procedure:
The different pulps were beaten in a valley beater for 0, 5, 15, 25, 35,
45 and 55 minutes except aspen pulp which was beaten for 45 minutes only.
The freeness values of the pulps at these intervals were determined according
to TAPPI standard method T227 M-50.
Forming of Handsheets:
Handsheets were prepared in accordance with TAPPI standard procedure
T205M-58 and these were conditioned in a constant temperature and humidity
room as specified by TAPPI standard practice.
Testing of Handsheets:
The handsheets were tested for basis weight, caliper, tensile strength,
bursting strength, tearing resistance and folding endurance, according to
TAPPI standard procedure T220M-53.
Presentation of Results
Experimental conditions, alkali consumption and yield are shown in Table
I A. The values for freeness and physical properties of handsheets are given T.A.B. -17-
in Tables I through VII. Breaking length, burst factor, and tear factor values were calculated based on oven-dry weight. The double folds were
° determined at a constant temperature and relative humidity of 70 F and 50 per cent respectively.
The values for breaking length, burst factor and tear factor plotted against freeness in ml are shown in Figure I. Beating time versus breaking length, burst factor and tear factor are shown in Figure II. Freeness plotted against beating time is given in Figure III.
Discussion of Results:
I. Pulping Results :
a) Alkali Consumption:
Alkali ccnsumption of pulps ranged from 4.2 - 6.9 per cent based on dry wood. Alkali consumption increased with increase in concentration of
liquor. The lowest alkali consumption was in experiment I where a low
quantity of alkali was applied with full size chips. The highest alkali
consumption of 6.9 per cent was observed when a concentration of 60 grams
per liter was used in experiment VII. The alkali consumption of pulp using
30 grams per liter concentration was within a narrow range of 5.6 - 5.9 per
cent. Aspen chips in experiment VI consumed 5.0 per cent of alkali based
on dry wood.
b) Screen Rejects:
The amount of screen rejects was high when relatively small quantities
of caustic soda were used (experiments I and IV). This condition was
obviously the result of inadequate liquor penetration. T.A.B. -18-
c) Yield:
The yield of pulps was in the range of 83-90 per cent based on oven dry wood, if determined before screening. Increased use of alkali resulted in decreased yield.
d) Freeness:
Aspen pulp was the lowest in freeness under the conditions of the experiment. Unbeaten aspen pulp had a Canadian freeness of 340 ml. All
Eucalyptus pulps were much higher in freeness which ranged from 600-740 ml.
The freeness drop with beating was more pronounced in Eucalyptus pulps prepared from crushed chips than from full sized chips. This may be due to better liquor penetration or may be the result of more fines in the pulp.
II. Strength Characteristics:
Evaluation of the seven experimentally produced pulps by the beater method yielded the following results:
a) The pulp produced from aspen chips was stronger than the six pulps prepared from Eucalyptus saligna.
b) When adequate liquor penetration was achieved, pulp from full size chips was stronger than pulp from crushed chips. This was seen in experiments
II and III where full sized and crushed chips were used respectively. The loss in strength observed in experiment III may be due to the reduction in fiber length as a consequence of crushing the chips.
c) &t lo�eL alkali ccncentLations, �ul�s obtained iLom cLusb.ed cb.i�s
had bettex stxength pxopexties than pulps obtained fxom full size chips. This T.A.B. -19-
is apparently due to better liquor penetration (see experiments I and IV).
d) The strength properties of the pulps increased by increasing alkali concentration of the pulping liquor. However, increasing the alkali concentration beyond 30 grams per liter did not show any-marked improvement in the strength properties of Eucalyptus pulps.
Conclusions
a) Eucalyptus saligna is suitable for the manufacture of cold caustic soda pulp.
b) Alkali concentration of 30 grams per liter on full size chips of
Eucalyptus saligna produced the best strength properties and fairly good yield.
c) The use of crushed chips is not advisable at higher alkali concentration�,
since a loss of strength results. 1lhere low alkali concentrations are used,
the crushing of chips improves liquor penetration with a reduction in the
quantity of screen rejects.
d) In no case did the Eucalyptus pulps reach the strength of aspen
pulps under the conditions of the experiments.
ACKNOWLEDGMENT
The assistance of Dr. A. H. Nadelman and the faculty of the Department
of Paper Technology is gratefully acknowledged.
Tachipully A. Bhaskaran *EXPERIMENTAL CONDITIONS, .ALKALI CONSUMPTION AND YIELD
Table lA
Expt. No. Wood Type of Caustic Soda Caustic pH of Liquor Screened Screen Totaltt Chips for Pulping Soda Con- Start End of Pulp per Reject Yield g/liter per sumed per of Steeping cent on percent cent on cent on Steeping wood on wood wood wood
I E. saligna full 15 7.5 4.2 12.1 12.1 45.8 41.3 87.1 size It It II 30 15 5.6 12.2 12.2 82.3 0.67 83.0
II III crushed 30 15 5.6 12.2 12.0 84.7 1.17 85.9
n II IV 15 7.5 5.9 12.3 12.0 77 .1 10.9 88.0 " II V 22.5 11.25 5.6 12.4 12.(3 89.0 1.3 90.3
VI Aspen full 30 15 5.0 12.3 12.0 86.7 0.5 87.2 size It VII E. sal igna 60 30 6.9 12.6 12 • .5 79.3 3.3 82.6
NOTES: * In all experiments: Steeping period was 2 hours Temperature was 23°c Liquor to wood ratio was 5:1
*"k Total yield includes screen rejects
] STANDARD BEATER EVALUATION OF COLD CUSTIC SODA PULPS FROM EUCALYPTUS SALIGNA
EXPT. I. Full Size Chips Concentration 15 grams per liter Table I Beating Freeness Basis Caliper Bulk !Apparent Bursti Breaking- Tear�' M. I. T. II Time Min. l
0 720 Naf not pos� ible to j orm hand� heets I II II 5 708 II " " 15 640 25 598 61.3 10.0 4.14 0.24 Could no1 419 15.3 couldnot 1 e measun d be rleasured II II 35 520 62.1 9.0 3.62 0.28 438 15.8
II It 45 460 60.0 8.2 3.47 0.29 761 13. 7
II II 55 355 62.0 7.6 3.ll o. 32 1019 16.1 * Not es that 1 he valuef were ca] culated c n oven-d1rY basis , ei!ht.
---�
EXP • II. F1 11 Siz Chips .. Concer tration 30 Srams ner lite1 Talle 2 .. Beating Freeness Basis Caliper Bulk !pparent Burst* Breakingi Tear* M.I.T. !Length Eac. .old _ Time Min. (C.S.F.) Iei�ht 0.001" cc/g Density Factor ml. g/m g/cc
0 730 61.2 7.7 3.19 o. 31 7.6 1972 37.6 0 -- 5 730 62.1 7.6 3.11 0.32 10.3 2362 39·.3 --1 - 15 495 61.5 6.8 2.81 0.35 10.6 2655 39.0 1 25 463 61.3 6.4 2.65 0.38 15.9 3207 37.9 1
35 412 62.3 6.4 2.61 0.38 14.3 3320 37.9 1.2
45 328 59.0 6.1 2.63 0.38 10.1 3572 39.0 1.4 .o 1.6 55 262 62.1 5.9 2.41 0.41 14.7 4417 37 -
-: NotJs that the values wre calculated cln oven-dtv basis vliSht. STANDARD BEATER EVALUATION OF --COLD CAUSTIC SODA PULPS FROM EUCALYPTUS SALIGNA
EXPT. III. Crushed Chips
Concentration 30 grams per liter Table 3 Beating Freeness Basis Caliper1 Bulk Apparent Burst* Breaking Tear1( M.I.T, Time Min. (C.S.F) Weight 0.001' cc/� Ina,.,,::; f-v 11.,+-- IT �--+h� i,:,-+-- ,.,._, .., L ·- m/1 g/m g/cc
0 610 62.2 8.0 3.27 0.31 4.5 1867 45.5 0.6 ~- 5 488 o. 2141 61.3 7,7 3.19 31 5.6 41.6 --0.8 15 439 62.2 7.1 2.90 0.34 6.9 2640 43.4 0.8 25 385 61.3 6.5 2.69 o. 37 9.3 2955 40.0 LO 35 309 63.3 11.3 6.5 2.60 0.38 3392 38.9 --1.2 45 226 63.4 6.1 2.44 0.41 12.9 3482 32�5 1.6
55 153 61.5 5.6 2. 31 0.43 15.1 4002 28.o --1.8 ._,, Notes that tl e values were cal< ulated 01 oven-dr basis WE ight.
---- EXPT.I� • Crushed Chips
Cot centratic n 15 anms per 1 ter Table 4
Beating Freeness Basis Caliper11 Bulk Apparent Burst* Breaking· Tear* M.I ..T. Time Min •. (£.S.F.) Weig�t 0.001 cc/g -Density Factor Length Fact-or Fold- ml g/m g/cc
0 590 61.0 9.6 4.00 0.25 1.58 82 22.8 couldn't
--be mea-sureII 5 570 62.5 9.0 3.66 0.27 2.63 1050 24.5
II 15 490 59.5 7.9 3.37 0.30 2.65 1271 22.5
It 25 444 60.0 7.3 3.09 o. 32 3.80 1688 20.0
It 35 319 62.0 7.1 2.91 o. 34 4.59 1941 21.8
II 45 272 61.7 6.9 2.84 0.35 4.56 1735 21.7 55 177 59. 3 6.5 2.78 0.36 5.89 2213 21.6 u * N< tes that the values were c, lculated on oven-c rv basis weight. - -- .______STANDARD BEATER EVALUATION OF COLD CAUSTIC SODA PULPS FROM EUCALYPTUS SALIGNA
EXPT. V. Crushed Chips Concentration 22.5 grams per liter Table 5 Beating Freeness Basis Caliper Bulk Apparent Bui;s'fk Breaking , Tear* M. I.T. 'j'imo Min. rc.s.F.'l T.Joioht 0 0011t ,..,../o nf\n!l.it"v l?""T"'..- li'<>f' +-nr h'!Jit--f- - 1.'nl ...l ml g/m� g/cc - - 0. 471 61.2 8.0 3. 32 o. 30 5.17 1882 33.2 1.0 . -- 7.5 0.33 32.3 5 428 62.0 3..-07 5.82 2073 1.0-- 15 333 61.6 6.8 2.80 0.36 7.08 2062 27.6 0.4
25 288 61.2 6.7 2.78 o. 36 7.47 2540 26.0 0.8 - - -- - 35 202 6.5 2.64 0.38 8.90 2700 25.4 1.0 62.5 - - 0 - - 45 160 62.5 6 •. 3 2.56 o. 39 9.99 2990 23.8
55 94 62.1 6.3 2.58 0.39 11.55 3311 24.9-- 0.6- *Not s that ttle values e were cal ulated op. oven dr � weight. - - -
- STANDARD BEATER EVALUATI )N OF COLD CAUSTIC -S09A PS ·FROM-A p-PB-N -- fizeh-i EXPT. fJI. Full ps- Concentrati on 30 g-r-alllS pe-r 1 ilter -Tafrl-e .,
- - Beating li'reeness Basis Caliper Bulk l\pparent J3urst7• l3reaking* Tear* M.I.T. 11 'l'-ime Min. (-C• S.• R..}-- Weiyht 0.001 cc/g Dens-i--t.y- l!'-ae-to-1'- Leng.th Rae.tor- .F-ol.d- ml g/m '/CC --- 0 340 61.1 6.07 2.52 0.40 18.5 4310 59 .• 7 7.0 - --- 5 288 61.3 5.46 2.26 0.44 19.7 4854 57.1 12.0
15 214 60.8 4.98 2.08 0.48 24.9 5687 49.0 12.2 - 25 160 62.8 4.88 - 1.97 0.51 28.2 5441 46.0 25.0 35 120 61.7 4.62 1.90 0.53 6111 - 29.3 --41.0 58.0 - 45 84 62.8 4.50 l.�2 0.55 30.6 - - 6342 46.7 50.0 -1, No es that he value P were ca culated, n oven-d ry basis 1-1eight. - -· - P ------
T - - - -- . --· -
- r STANDARD BEATER EVALUATION OF COLD CAUSTIC SODA PlJLP FROM EUCALYPTUS SALIGNA
EXPT. VII Full Siz ChiJ2S Concentration 60 srams 12er liter Table 7 Beating Freeness Basis Caliper Bulk !Apparent Burst* Breaking'/, Tear* M.I.T. l'T'i-,, Min (C.S.F.) TJ,:, i .-.'hf- f'I f'lf'lln ,..,../,. lnt>n<>i+-n re,",....___ Ir,,..,o-+-'h - h' 35 318 61.1 6.13 2.55 0.39 -14.5 3722 38.8 2 -- 45 275 2.34 -- 60.4 5.57 --0.43- 16.5 3925 41.1 2 -- 55 196 61.6 5.46 2.25 -o.44 16.3 4124 39 .6 2 �•� Ne Cc - tes that the value s were lculated on oven-c rv basis �eight. -- - - -- ------ ------ - -- - � - --- . - - -- . ------�-- -- . T ------�---- ------. - - -f------r------�------f s:.·�qci,JrJ nr·:n:c·r I�\.ci�uurion ,,f . ..1-,d... j.tts .Sal�:_:;n . 1 .ina .\Sp<.!n Pulps '!;'ig. i = 1 / ' ; :· · -· .· · · - · 1 �-· c 1 -r1 = ¾ tJ � i ,_Jc r�rr- ··tt0±.:·1� l l · ;;;tf?.:t;·:_¥:Jij�_:-:·_::r;-_J.t�:� � e:/- _ k�J (<;:�:: r-�--:r1C�= f-:�)L%:-��:tti t:j½4�j�f=�t�ji:�f�ILL� kt�:-!- r�r�� 6 =�<-:;�� � . 1 i · · · ···• .. · - · '•· ' · · '· · I- ' ] "" � ; -·· ... 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