PAPERmaking! Vol5 Nr2 2019

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PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 5, Number 2, 2019 CONTENTS:

FEATURE ARTICLES: 1. Pulp Fractionation : Influence of fibre fractionation on kraft paper properties. 2. Fillers : Characterising El Minia limestone for use in papermaking. 3. RCF & Nanocellulose : Producing nanocellulose from RCF. 4. Composting : Composting of paper packaging containers. 5. Analysis : Analysis of cellulose nanocrystals using flow cytometry. 6. Barrier Coating : Bio-base polymers for barrier coating – a review. 7. Carton Creasing : Testing folding performance of coated paperboard. 8. Wood Panel : Machining parameters for controlling surface roughness of MDF. 9. QCL on COD Analysis : PeCOD L50 analyser, and a PeCOD case study. 10. Pumps : Case study for reducing pump energy use in the Paper Industry 11. Steam Boiler Safety : BG01 Guidance on Safe Operation of Steam Boilers 12. Summarising Skills : How to summarise written text. 13. Rapid Reading : Tips for skim reading and scan reading. 14. Note Taking : Two model methods for taking notes. 15. Leadership : The SBI-I feedback model. 16. Driving : Various tips to improve driving performance in the UK. 17. Wellbeing: Nutrition : Reducing sugar intake. 18. Wellbeing: Stress : Understanding stress management. 19. Wellbeing: Mowvember : Outlining why November is so important for Men ’ s health. SUPPLIERS NEWS SECTION: Products & Services : Section 1 – PITA Corporate Members: ABB / ANDRITZ / VALMET Section 2 – Other Suppliers Chemicals / Materials Handling / Testing & Analysis / Miscellaneous DATA COMPILATION: Installations : Overview of equipment orders and installations since April 2019 Research Articles : Recent peer-reviewed articles from the technical paper press Technical Abstracts : Recent peer-reviewed articles from the general scientific press Events : Information on forthcoming national and international events and courses The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .

Contents

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PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 5, Number 2, 2019

Influence of fiber fractionation on kraft paper properties of European black pine and European aspen Sezgin Koray GÜLSOY and Ayben KILIÇ PEKGÖZLÜ. In this study, the kraft pulps of European black pine ( Pinus nigra Arn .) and European aspen ( Populus tremula L .) were fractionated according to fiber length in a Bauer McNett classifier and effects of fiber fractionation on paper properties were investigated. Bauer McNett screens used for European black pine and European aspen were 16, 30, 50, and 100 mesh and 30, 50, 100, and 200 mesh, respectively. The handsheet surface of each fraction was observed by field emission scanning electron microscopy (FE-SEM). The results showed that handsheet properties were statistically significantly affected by fiber fractionation. The effect of fiber fractionation on tensile and burst indices of handsheets depended on the wood species. However, tear index, apparent density, and surface roughness of handsheets showed similar trends in the two species. Contact information: Department of Forest Products Engineering, Faculty of Forestry, Bartın University, Bartın, Turkey Turk J Agric For (2019) 43: 184-191 © TÜBİTAK doi:10.3906/tar-1605-46.

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .

Article 1 – Pulp Fractionation

Page 1 of 9

http://journals.tubitak.gov.tr/agriculture/ Turkish Journal of Agriculture and Forestry

Turk J Agric For (2019) 43: 184-191 © TÜBİTAK doi:10.3906/tar-1605-46

Research Article

Influence of fiber fractionation on kraft paper properties of European black pine and European aspen

Sezgin Koray GÜLSOY* B , Ayben KILIÇ PEKGÖZLÜ B Department of Forest Products Engineering, Faculty of Forestry, Bartın University, Bartın, Turkey

Received: 11.05.2016

Accepted/Published Online: 09.12.2018

Final Version: 01.04.2019

Abstract: In this study, the kraft pulps of European black pine ( Pinus nigra Arn.) and European aspen ( Populus tremula L.) were fractionated according to fiber length in a Bauer McNett classifier and effects of fiber fractionation on paper properties were investigated. Bauer McNett screens used for European black pine and European aspen were 16, 30, 50, and 100 mesh and 30, 50, 100, and 200 mesh, respectively. The handsheet surface of each fraction was observed by field emission scanning electron microscopy (FE-SEM). The results showed that handsheet properties were statistically significantly affected by fiber fractionation. The effect of fiber fractionation on tensile and burst indices of handsheets depended on the wood species. However, tear index, apparent density, and surface roughness of handsheets showed similar trends in the two species. Key words: Bauer McNett, European aspen, European black pine, fiber fractionation, paper properties

1. Introduction Fiber dimensions have a remarkable influence on the papermaking potential of pulp. The paper properties (strength, surface roughness, porosity, density, etc.) are significantly affected by fiber length, fiber width, cell wall thickness, fiber flexibility, and fiber collapsibility (Pulkkinen et al., 2006). Hardwood fibers have been generally used to achieve good surface properties, while softwood fibers are used for high strength. Therefore, fiber sources used in pulp mill have been appropriately selected according to the quality requirements of the final product. Fiber fractionation means separation of mixed fibers into two or more parts based on properties such as length, flexibility, and coarseness (Gooding and Olson, 2001; Sood et al., 2005). In mill scale, pulp can be fractionated in hydrocyclones, or in pressure screens using slotted or holed screen plates/baskets (Asikainen et al., 2010). However, Bauer McNett or Clark fiber classifiers are used in the laboratory. The traditional approach in fiber preparation is to use the fibers collectively without fractionating them. Although this approach facilitates the process design, it ignores the opportunity to use the natural advantages of the individual fiber fractions (Gooding and Olson, 2001). On the other hand, fractionation of pulp furnish offers the potential to produce customer-valued products from fiber sources. Thus, papermakers can produce paper with optimum properties for specific applications by controlling

process variables such as the refining conditions, use of additives, and dewatering conditions at the wet end (Sood et al., 2005; Azizi Mossello et al., 2010b). Abubakr et al. (1995) in recycled fiber, Demuner (1999) in bleached eucalyptus kraft pulp, Reyier (2008) in Norway spruce ( Picea abies ), and Hafrén et al. (2014) in mixed softwood (lodgepole pine, Sitka spruce, Western balsam fir) studied the effects of fiber fractionation on paper properties. Huang et al. (2012) investigated the fiber morphology of each fraction after fiber fractionation of Jack pine ( Pinus banksiama ) thermomechanical pulp. However, there are no published data related to effects of fiber fractionation on paper properties of European black pine ( Pinus nigra Arn.) and European aspen ( Populus tremula L.). In this scope, the objective of this study was to determine the effects of fiber fractionation on handsheet properties of European black pine and European aspen. 2. Materials and methods The wood samples of European black pine and European aspen were obtained from Bartın Province in Turkey. They were debarked and chipped into approximately 3.0–1.5– 0.5 cm in size. Chips were air-dried and stored with less than 10% moisture content until used. Table 1 shows the kraft pulping conditions of European black pine and European aspen. Kraft pulping was done in an electrically heated laboratory cylindrical type rotary

* Correspondence: szgngulsoy@yahoo.com

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GÜLSOY and KILIÇ PEKGÖZLÜ / Turk J Agric For

digester of 15 L. Chips (750 g, oven-dried basis) for each cooking experiment were cooked in the digester. After cooking, pulps were washed with tap water to remove residual liquor. After washing, pulps were disintegrated, washed with tap water, and screened on a slot screen of 0.15 mm (TAPPI T 275). The Bauer McNett classifier (model with 4 classifier chambers) was used for fiber fractionation of kraft pulps according to TAPPI T 233 cm-06. In fiber fractionation of European black pine pulp, R16 (1.190 mm, retained fibers of a 16-mesh screen), P16/R30 (0.595 mm, i.e. passed 16 mesh, retained 30 mesh), P30/R50 (0.297 mm), and P50/ R100 (0.149 mm) classifier screens were used. In fiber fractionation of European aspen pulp, R30, P30/R50, P50/ R100, and P100/R200 classifier screens were used. Fiber morphology of each fiber fraction was determined with a light microscope. Fiber dimensions of each fractions were measured (n: 100). The aspect ratio (fiber length/fiber width) and flexibility ratio [(lumen width/fiber width) × 100] were calculated using the measured fiber dimensions. Handsheets of 75 g/m 2 from each fiber fraction, made with a Rapid-Kothen Sheet Former (ISO 5269-2), were conditioned (TAPPI T 402). Tensile index, tear index,

burst index, and apparent density of the handsheets were measured according to the T494, T414, T403, and T220 TAPPI standards, respectively. Also, roughness of the handsheets was determined according to the ISO 8971-2 standard method. The handsheets of each fiber fraction were coated with gold (80%) and palladium (20%) using a sputter coater (Quorum Q150 T) and were observed by field emission scanning electron microscopy (FE-SEM) (Tescan MAIA3 XMU) operating at 10 kV. The coating thickness was approximately 10 nm. The data of handsheet properties for each fiber fraction were subjected to analysis of variance (ANOVA) and Duncan test at 0.05 probability level. Different lowercase letters used in figures denotes that the difference in the average values of properties among the compared groups

was statistically significant. 3. Results and discussion

The results of Bauer McNett and fiber morphology for European black pine and European aspen are shown in Table 2. It can be seen that the fiber length and fiber width of both species decreased with increasing screen mesh.

Table 1. Kraft pulping conditions of European black pine and European aspen.

Conditions

European black pine

European aspen

Active alkali (%)

20 25

16 20

Sulfidity (%)

Temperature (°C)

170

Time to max. temperature (min) Time at max. temperature (min)

90 60

Total cooking time (min)

150 4/1

Liquor/chip ratio

Table 2. The results of fiber fractionation of European black pine and European aspen.

Wood species

Fiber fractions

Fiber ratio (%)

Fiber length (mm)

Fiber width (μm)

Double wall thickness (μm)

Lumen width (μm)

Aspect ratio

Flexibility ratio

R16 R30 R50

65.8 17.2

3.32 ± 0.02 40.40 ± 0.1 21.20 ± 0.3 2.75 ± 0.04 39.00 ± 0.1 18.25 ± 0.2 2.13 ± 0.04 37.10 ± 0.5 20.35 ± 0.1 1.33 ± 0.02 35.10 ± 0.2 19.25 ± 0.3

19.20 ± 0.2 79.70 47.52 20.75 ± 0.3 72.56 53.21 16.75 ± 0.1 62.26 44.15 15.85 ± 0.2 38.46 44.16

European black pine

7.6 3.9

R100

R200 + fines 5.5

R30 R50

38.1 30.6 25.9

1.27 ± 0.01 25.0 ± 0.1 11.35 ± 0.1 1.09 ± 0.01 24.5 ± 0.1 11.50 ± 0.1 0.89 ± 0.02 23.7 ± 0.1 11.80 ± 0.2 0.60 ± 0.01 21.4 ± 0.1 12.20 ± 0.1

13.65 ± 0.2 50.40 54.60 13.00 ± 0.1 45.31 53.06 11.90 ± 0.1 38.40 50.21

European aspen

R100 R200 Fines

2.1 3.3

9.20 ± 0.2

32.24 42.99

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Also, increased screen mesh resulted in lower fiber aspect ratio. The weight percentage of long fiber fractions was 83% and 68.7% for European black pine and European aspen, respectively. Fiber fraction had a statistically significantly effect on tensile index (P < 0.05). Also, effect of fiber fraction depended on the wood species (Figure 1). Tensile indexes of R16, R30, R50, and R100 fractions in European black pine kraft pulp were determined as 39.71 Nm/g, 45.30 Nm/g, 43.96 Nm/g, and 34.86 Nm/g, respectively (P < 0.05). These results can be explained by long and stiff fibers of lower screen numbered fractions, which have poor bonding characteristics (Huang et al., 2012). Tensile index depends on bonding ability of fibers (Rydholm, 1967; Levlin, 1999, Dutt et al., 2009; Jahan and Rawshan, 2009). Flexible fibers produce large contact areas for fiber-

to-fiber bonding. In European aspen samples, tensile indexes of R30, R50, R100, and R200 fractions were found as 33.22 Nm/g, 38.47 Nm/g, 42.20 Nm/g, and 46.85 Nm/g, respectively. This result can be attributed to increasing vessel element numbers in high screen mesh fractions. Thin-walled vessel elements collapse during papermaking, and their wide surface increases the interfiber bonding. On the other hand, it can be ascribed to the high apparent density of handsheets of high screen mesh numbered fractions. Higher density indicates better interfiber bonding in the sheet. A positive correlation between screen mesh number and tensile index has also been reported in previous studies (Reyier, 2008; Hafrén et al., 2014). The relationships between the fiber fraction and tear index of handsheets are presented in Figure 2. As can be seen in Figure 2, the tear index of handsheets

R50 R100 European aspen

R16

R30 R50 European black pine

R100

R30

R200

Figure 1. Effect of fiber fractionation on the tensile index of handsheets.

R16

R30 R50 European black pine

R100

R30

R200

R50 R100 European aspen

Figure 2. Effect of fiber fractionation on the tear index of handsheets.

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of both species decreased significantly (P < 0.05) with increasing screen number. The highest tear index values were determined in the R16 fraction at 11.35 mNm 2 /g for European black pine and in the R30 fraction at 3.03 mNm 2 /g for European aspen. Increase in tear index with decreasing screen mesh numbers could be attributed to a positive correlation between fiber length and tear index (Casey, 1961; Horn, 1978; Seth and Page, 1988; Mohlin, 1989; Horn and Setterholm, 1990; Seth, 1990; Scott et al., 1995; Retulainen, 1996; Levlin, 1999; Shin and Stromberg, 2005, Azizi Mossello et al., 2010a), and also higher aspect ratio of longer fiber (Rydholm, 1965; Shakhes et al., 2011) (Table 2). In addition, the increase in fiber flexibility (a higher sheet density and better interfiber bonding) causes a higher tear index (Bronkhorst and Bennett, 2002). On the other hand, the decrease in tear index with increasing screen mesh numbers could be ascribed to increasing vessel elements numbers with decreasing screen mesh numbers. The vessel elements are generally short and thin- walled, with pitting and open ends (Li et al., 2012). The vessel element-rich fractions cause a decrease in the tear index compared to that of vessel element-poor fractions (http://www.eucalyptus.com.br/capitulos/ENG04_vessels. pdf). Abubakr et al. (1995) noted that tear index of long fiber fractions in recycled pulp fractionation was higher than that of short fiber fractions. The relationships between the fiber fractions and burst index of handsheets are presented in Figure 3. Burst index of European black pine handsheets decreased with increasing screen mesh (P < 0.05), while burst index of European aspen handsheets increased with increasing screen mesh (P < 0.05). The lowest and highest burst index values of European black pine samples were determined in R100 and R30 fractions as 1.43 kPa m 2 /g and 1.99 kPa m 2 /g, respectively. This result can be explained by fiber

flexibility differences between R100 and R30 fractions (Table 2). Also, it can be attributed to decreasing fiber length with increasing screen mesh (Table 2). The lowest and highest burst index values of European aspen samples were found in the R30 and R200 fractions at 1.12 kPa m 2 /g and 1.90 kPa m 2 /g, respectively. The high burst index with rich vessel element fractions can be ascribed to improved fiber bonding due to collapsed vessel elements during papermaking. In recycled pulp fractionation, higher burst index of long fiber fractions than short fiber fractions was reported by Abubakr et al. (1995). As can be seen in Figure 4, apparent density of handsheets in both species was positively correlated with increasing screen mesh (P < 0.05) (Figure 4). These results can be explained by short and narrow fibers of higher screen numbered fractions, which give a compact structured paper due to more fibers per area. The lowest apparent density values were determined in the R16 fraction at 470 kg/m 3 for European black pine and in the R30 fraction at 580 kg/m 3 for the European aspen. A positive correlation between apparent density and mesh screen was also reported by Reyier (2008). It is known that the relationship between bulk and apparent density is negatively correlated. Demuner (1999) noted that the fine fractions produced sheets with lower bulk than the coarse fractions. The results indicated that roughness of handsheets increased with increasing screen mesh (P < 0.05) (Figure 5). Roughnesses of R16, R30, R50, and R100 fractions in European black pine kraft pulp were determined as 1566 mL/min, 1228 mL/min, 1053 mL/min, and 826 mL/min, respectively. In European aspen samples, roughnesses of R30, R50, R100, and R200 fractions were found as 1275 mL/min, 891 mL/min, 654 mL/min, and 536 mL/min, respectively. These findings can be explained by shorter

2.5

1.5

0.5

R16 R100 European aspen Figure 3. Effect of fiber fractionation on the burst index of handsheets. R100 R30 R30 R50 European black pine R50

R200

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0.75

0.6

0.45

0.3

0.15

R16

R30 R50 European black pine

R100

R30

R50 R100 European aspen

R200

Figure 4. Effect of fiber fractionation on the apparent density of handsheets.

1000 1200 1400 1600 1800

0 200 400 600 800

R50 R100 European aspen

R16

R30 R50 European black pine

R100

R30

R200

Figure 5. Effect of fiber fractionation on the roughness of handsheets.

index increased. Apparent density of handsheets in both species was positively correlated with increasing screen mesh. Fiber fractionation may not be technically feasible for mill-scale paper production, but papermaking from unfractionated fibers ignores the opportunity to use the natural advantages of the individual fiber fractions. Also, selective refining of fractions results in paper quality improvements. More studies related to effects of fiber fractionation (especially the effect of vessel element-rich and element-poor fractions) on paper properties of other lignocellulosic materials have to be carried out. Acknowledgment This research was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK, Project Number: 113O146). The authors are thankful to TÜBİTAK for the financial support.

and finer fibers of high screen mesh fractions (Table 2; Figures 6 and 7). This result can also be attributed to the action of vessel elements in fractions of European aspen samples that are rich in vessel elements (Malik et al., 2004). Demuner (1999) reported that the smoothness of fine fractions was higher than that of coarse fractions. FE-SEM handsheet micrographs of each fractionation of European black pine and European aspen are shown in Figures 6 and 7, respectively. In conclusion, the results of this study have shown that the handsheet properties were statistically significantly affected by fiber fractionation. In European black pine samples, tensile index, tear index, burst index, and roughness of handsheets decreased with increasing screen mesh number. In European aspen samples, tear index and roughness of handsheets decreased with increasing screen mesh number, while tensile index and burst

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Figure 6. FE-SEM handsheet micrographs of each fractionation of European black pine kraft pulp: a, b) R15; c, d) R30; e, f) R50; g, h) R100.

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Figure 7. FE-SEM handsheet micrographs of each fractionation of European aspen kraft pulp: a, b) R30; c, d) R50; e, f) R100; g, h) R200.

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References Abubakr SM, Scott GM, Klungness JH (1995). Fiber fractionation as a method of improving handsheet properties after repeated recycling. TAPPI J 78: 123-126. Asikainen S, Fuhrmann A, Robertsén L 2010. Birch pulp fractions for fine paper and board. Nord Pulp Pap Sci 25: 269-276. Azizi Mossello A, Harun J, Resalati H, Ibrahim R, Shmas SRF, Tahir PM (2010a). New approach to use of kenaf for paper and paperboard production. Bioresources 5: 2112-2122. Azizi Mossello A, Harun J, Tahir PM, Resalati H, Ibrahim H, Shamsi SRF, Mohmamed A (2010b). A review of literatures related of using kenaf for pulp production (beating, fractionation, and recycled fiber). Mod. Appl Sci 4: 21-29. Bronkhorst CA, Bennett KA (2002). Deformation and failure behaviour of paper: tear strength. In: Mark RE, Habeger CC, Borch J, Lyne MD, editors, Handbook of Physical Testing of Paper, Vol. 1. 2nd ed. New York, NY, USA: Marcel Dekker Inc., pp. 388-395. Casey JP (1961). Pulp and Paper Chemistry and Chemical Technology. Vol. 2, Papermaking. New York, NY, USA: Interscience Publishers Inc. Demuner BJ (1999). Opportunities for market pulp differentiation via fractionation. In: 5th International Paper and Board Industry Conference – Scientific and Technical Advances in Refining, 29–30 April 1999, pp. 1-14. Dutt D, Upadhyay JS, Singh B, Tyagi CH (2009). Studies on Hibiscus cannabinus and Hibiscus sabdariffa as an alternative pulp blend for softwood: an optimization of kraft delignification process. Ind Crop Prod 29:16-26. Gooding RW, Olson JA (2001). Fractionation in a Bauer-McNett classifier. J Pulp Pap Sci 27: 423-428. Hafrén J, Fernando D, Gorski D, Daniel G, Salomons FA (2014). Fiber- and fine fractions-derived effects on pulp quality as a result of mechanical pulp refining consistency. Wood Sci Technol 48: 737-753. Horn RA (1978). Morphology of Pulp Fiber from Hardwoods and Influence on Paper Strength. Madison, WI, USA: USDA Forest Service Forest Products Laboratory. Horn RA, Setterholm VC (1990). Fiber morphology and new crops. In: Janick J, Simon JE, editors. Advances in New Crops. Portland, OR, USA: Timber Press, pp. 270-275. Huang F, Lanouette R, Law KN (2012). Morphological changes of jack pine latewood and earlywood fibers in thermomechanical pulping. Bioresources 7: 1697-1712. Jahan MS, Rawshan S (2009). Reinforcing potential of jute pulp with Trema orientalis (Nalita) pulp. Bioresources 4: 921-931.

Levlin JE (1999). General physical properties of paper and board. In: Levlin JE, Söderhjelm L, editors. Pulp and Paper Testing, Papermaking Science and Technology, Book 17. Jyväskylä, Finland: Fapet Oy, pp. 137-162. Li Z, Zhai H, Zhang Y, Yu L (2012). Cell morphology and chemical characteristics of corn stover fractions. Ind Crop Prod 37: 130- 136. Malik RS, Dutt D, Tyagi CH, Jindal AK, Lakharia LK (2004). Morphological, anatomical and chemical characteristics of Leucaena leucocephala and its impact on pulp and paper making properties. J Sci Ind Res India 63: 125-133. Mohlin UB (1989). Fiber bonding ability − A key pulp quality parameter for mechanical pulps to be used in printing papers. In: International Mechanical Pulping Conference, Helsinki, Finland, pp. 49-57. Pulkkinen A, Ala-Kaila K, Aittamaa J (2006). Characterization of wood fibers using fiber property distributions. Chem Eng Process 45: 546-554. Retulainen E (1996). Fiber properties as control variables in papermaking. Part 1. Fibre properties of key importance in the network. Pap Puu 78: 187-194. Reyier S (2008). Bonding ability distribution of fibers in mechanical pulp furnishes. Licentiate Thesis. Mid Sweden University, Sundsvall, Sweden. Rydholm SA (1965). Pulping Process. New York, NY, USA: Interscience Publisher. Scott WE, Abbott JC, Trosset S (1995). Properties of Paper: An Introduction. Atlanta, GA, USA: TAPPI Press. Seth RS (1990). Fibre quality factors in papermaking - I. The importance of fibre length and strength. In: Proceedings of Material Research Society Symposium, San Francisco, CA, USA, pp. 125-141. Seth RS, Page DH (1988). Fiber properties and tearing resistance. TAPPI J 71: 103-107. Shakhes J, Marandi MAB, Zeinaly F, Saraian A, Saghafi T (2011). Tobacco residuals as promising lignocellulosic materials for pulp and paper industry. Bioresources 6: 4481-4493. Shin NH, Stromberg B (2005). Impact of cooking conditions on physical strength of Eucalyptus pulp. In: Colóquio Internacional sobre Cellulose Kraft de Eucalipto, Concepción, Chile, 2005.Sood YV, Pande PC, Tyagi S, Payra I, Nisha AG, Kulkarni AG (2005). Quality improvement of paper from bamboo and hardwood furnish through fiber fractionation. J Sci Ind Res India 64: 299-305.

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Characterizations of El Minia limestone for manufacturing paper filler and coating Gaber M.A. WAHAB. This study introduces a contribution of using the El Minia carbonate filler pigment for paper making. El Minia limestone samples were grind to very fine powder ranging from 2 to 10μm, for utilization in paper filler/coating industry, with using testing techniques; X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning electron microscopy (SEM). The limestone assessment includes more examinations to confirm the suitability of studied samples for alkaline paper manufacture such as, chemical analysis and physical properties, brightness, refractive index, oil & water absorption, moisture content, water soluble, surface area and soundness tests as per paper industry standards. Contact information: Egyptian Petroleum Research Institute, Exploration Department, Nasr City, Cairo, Egypt M.A.W. Gaber, Characterizations of El Minia limestone for manufacturing paper filler and coating, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.007

Article 2 – Fillers

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Full Length Article Characterizations of El Minia limestone for manufacturing paper filler and coating q Gaber M.A. Wahab

Egyptian Petroleum Research Institute, Exploration Department, Nasr City, Cairo, Egypt

article info

a b s t r a c t

Article history: Received 7 September 2016

This study introduces a contribution of using the El Minia carbonate filler pigment for paper making. El Minia limestone samples were grind to very fine powder ranging from 2 to 10 l m, for utilization in paper filler/coating industry, with using testing techniques; X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning electron microscopy (SEM). The limestone assessment includes more examinations to confirm the suitability of studied samples for alkaline paper manufacture such as, chemical analysis and physical properties, brightness, refractive index, oil & water absorption, moisture content, water soluble, surface area and soundness tests as per paper industry standards. 2017 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Revised 20 June 2017 Accepted 12 July 2017 Available online xxxx

Keywords: Calcium carbonate Paper filler El Minia Inorganic pigment

1. Introduction

There are different grades of paper used for many purposes, for example: coated, uncoated, bond, note book, offset, index, news- print, computer, copier, gloss, picture and inkjet papers. The main types of mineral filler for acid papers are talc, hydrous kaolin, calcined kaolin, precipitated silica’s /silicates (PSS), and tita- nium dioxide. For neutral/alkaline papers, talc, hydrous kaolin, cal- cined kaolin, PSS, titanium dioxide, ground calcium carbonate (GCC), and precipitate calcium carbonate (PCC) are used. The esti- mated productions of some types of paper and paperboard in 2008 were illustrated in (Fig. 1). Kaolin, calcium carbonate (GCC and PCC), and talc are the most widely used mineral fillers, with regional variations depending on local resources available (Fig. 2). Filler pigments must have a high degree of whiteness, a high index of refraction, small particle size, low solubility in water, and low specific gravity. It is also important that the filler be chemically inert to avoid reactions with other components in the sheet and in the papermaking system. The filler should contain a minimum of impurities, and the grit content must be low to avoid excessive wear of the wire and other processing equipment such as cutting blades. Furthermore, unless the filler has very unusual properties, it must be inexpensive [1–6] The annual Egyptian production of paper in Egypt about 150,000 tons while the domestic consumption about 650,000 tons, to compensate the difference between production and consump- tion, there is a large import quantities cost a lot of hard currencies. The percentage of filler used to produce different types of paper products are indicated in Table 1. There are many Egyptian companies for paper making, the most important production companies rankled as annual production is

Calcium carbonate ‘‘CaCO3”, is one of the most important and useful materials in many industries. It is extremely common and found throughout the world in sedimentary rocks. It comprises more than 4% of the earth’s crust. Calcium carbonates natural forms are chalk and limestone, produced by the sedimentation of the shells of small fossilized snails, shellfish, and coral over mil- lions of years. Although all three forms are identical in chemical terms, they differ in many other respects, including purity, white- ness, thickness and homogeneity. The paper industry uses limestone-based product to manufac- ture fillers and coating pigments. Calcium carbonate pigment is used for filling and coating, for example in making of printing papers and board. CaCO3 valued worldwide for high brightness and light scattering characteristics, as well as it is used as an inex- pensive filler to make bright opaque paper. Also it helps to produce papers with high whiteness and gloss and good printing properties. In 2008, world production of paper and paperboard was 380 million tons according to Food and Agriculture Organization (FAO). Over 90% of paper and paperboard is produced in Asia, Eur- ope and North America. Asia is the biggest producer with 34% of all production and Europe and North America are trailing with 30% and 29% respectively.

Peer review under responsibility of Egyptian Petroleum Research Institute. E-mail address: Mgaber01@hotmail.com

http://dx.doi.org/10.1016/j.ejpe.2017.07.007 1110-0621/ 2017 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Please cite this article in press as: M.A.W. Gaber, Characterizations of El Minia limestone for manufacturing paper filler and coating, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.007

M.A.W. Gaber / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

stone, this unit is conformably overlain by snow white, soft, fossiliferous limestone of Samalut Formation. Samalut Formation overlain by creamy white, mictritic, marly limestone of the Magha- gha Formation. This unit is conformably overlain by brownish yel- low, sandy, fossiliferous limestone of Qarara Formation. The top most part of Qarara Formation includes nodular, chalky, limestone of Fashn Formation. The studied sample was collected from El Minia and Samalut formations for laboratory examinations (Fig. 3).

3. Materials and methods

Thirty samples were collected from different localities along the area in between El Minia city and Beni Khalid to represent the studied limestone, the representative samples were ground to very fine particles for measuring the physical properties, chemical anal- ysis, and X-ray diffraction, and SEM studies. Carbonate samples were subjected to specific tests and evalua- tion compare with the international specification and standard to determine their suitability for alkaline paper and paperboard filler/coating manufacture. The assessment of ground calcium carbonate characterizations were conducted according to the following standards: Specific gravity ASTM D 153, Oil absorption ASTM D 234 and ASTM D 281, Water absorption, Moisture content ASTM D 280, Particle size, Particle shape, ASTM E 70 of Hydrogen ion concentration, ASTM D 2196 for Matter soluble in water: max 1%, Hardness, Appearance & Color of powder, Brightness, purity as CaCO3: 95%, Refractive index, SEM, chemical analysis, XRD, and soundness test. Standard properties of ground, precipitated and kaolin ores utilized in paper making are listed in Table 2 as a references for studied sample.

Fig. 1. Global production of paper and paperboard grades in 2008 (Finnish forest Industries 2009).

4. Results and discussions

Fig. 2. Breakdown of filler pigment used for paper making at 2002 (Harris 2004).

The physical and chemical assessment tests were accomplished for El Minia carbonate samples as follows: Calcium carbonate filler pigment represent a considerable part of paper manufacture, the amount of filler vary from 5% to 30% of the whole finish. Several reasons why fillers are used in paper- making, the main reasons are their low cost compared to fibers ‘‘The price of bleached chemical fiber is roughly five to seven times as much as filler prices” and their ability to improve optical prop- erties in the final product. Fillers can also improve surface proper- ties of paper and by that have a positive effect on the printability of the final product [10,11]. Also fillers can improve the surface properties of paper or paperboard as well as have positive effects on the opacity, bright- ness and colour. Opacity is increased because of filler particles scatter light very well [12]. Fillers also have a smoothening effect on the paper surface, because small filler particles settle in between of fibers they together form a smooth paper surface, which is required in roto- gravure printing. Although fillers are needed for good printing image, excessive amount of filler will compromise the paper sur- face strength. The chemical analysis of samples collected from El Minia areas were examined to ensure that the limestone samples used as a pig- ment are inert, stable and not contain detrimental impurities. The chemical analysis results revealed that the major elements is CaO, accordingly the CaCO3 content ranging from 99.30 to 99.65%. The physical and chemical analysis was conducted at the Egyptian Pet- roleum Research Institute and Egyptian Mineral resources Author- ity ‘‘Central laboratories Sector”, and the results obtained are illustrated in Tables 4 and 5. These testing for calcium carbonate powder were carried out according the following techniques and testing:

Table 1 Paper product and filler contents. 0–15% Newsprint 20–32% SC gravure paper 6–10% LWC base paper 8–15% Wallpaper

5–10% Mechanical catalogue 5–20% Wrapping base paper 10–25% Wood free printing paper 10–25% Wood free writing paper

2–10% Corrugated board 2–10% wallpaper board

Qena company with annually production about 120,000 tons, Al Ahlya (EMAC) with annual production 60,000 tons, and Rakta com- pany produces 30,000 tons [7] This article aims to contribute the utilization of El Mina huge quantities of high grade calcium carbonate and its suitability for making of filler/coating of paper and paperboard and stop the loss of hard currency used for importing the same ore.

2. Geological setting

EI Minia-Maghagha area has a rectangular shape and lies on the Eastern side of the Nile River. It is located between latitude 28 and 28 40 0 N and longitudes 30 50 0 and 31 30 0 E. The exposed carbonate rocks of El Minia-Maghagha areas includes five units of Middle Eocene age. These units are composed mainly of limestone [8,9]. The oldest exposed unit is El Minia For- mation which is composed of white, hard, and fossiliferous lime-

M.A.W. Gaber / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

a- Outcrop of limestone

b- Quarry of chalky limestone

c- Cutting of limestone building blocks

d- location of limestone quarry's

Fig. 3. Field photos showing outcrop and quarry of pure limestone at El Minia East Nile Valley.

4.1. Specific gravity

Table 2 Properties standard limits of Kaolin, PCC and GCC fillers used in paper manufacture.

The representative samples of limestone measured according to [13] and the results are ranging from 2.6 to 2.7 g/cm 3 as indicated in Table 4. , as per standard the low specific gravity is preferred for paper manufacture.

Property

Kaolin

PCC

GCC

Brightness Particle size

80 85%

90–97%

> 90–96%

2 l m

Manufacture fine high at high load

Required grinding

Opacity

Excellent

Moderate at high load

4.2. Oil absorption

Loading level

20–30%

Limited to 20% 20–30%

The test were carried out using linseed oil mixed with carbonate powder and the specific paste obtained at the ratio of oil quantity is ranging from 32 to 36 g/100 g (g of oil/g of powder), as per [14,15].

Sheet strength Good

Moderate

Excellent

Bulking

Moderate

Good High

Good

Absorption Chemical

Low Inert

Low

Unstable in acid

reactivity

4.3. Moisture content

Flexibility

Filler/Coating Mainly filler

Alkaline - filler/coating

Processing

Extensive

Energy extensive

Grinding/sizing

The moisture content of limestone powder was determined at 105 C and the results ranging from 0.05 to 0.07% and considered low percentage moisture according to [16].

Availability

Restricted

Satellite plants Geologically plentiful

Price

Low (N. America)

Based on cost

Low (Europe)

4.4. Particle size

Calcium carbonate pigments for paper making occurs in the form of a fine powder or lumps by using crushing equipment’s was ground to very fine grains. The recommended size of lime- stone powder pigment shall be in limit of 2–10 l m as shown in (Fig. 4). The vast majority of particles are much smaller in size than 10 m m; there is some evidence that a mixture of particle sizes is desirable for increased durability, reduced absorption and reduced permeability of the film, also the particle size distribution graph (Fig. 5), showing that the 80% of analyzed sample is less than 10 l m in size.

Table 3 Brightness of El Minia calcium carbonate.

Limestone samples Brightness (z-direction) Sample 1 91 Sample 2 93.5 Sample 3 90.5 Sample 4 91.5

M.A.W. Gaber / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

Table 4 Physical properties of limestone filler pigment.

Ore Type

Physical Properties Sp. Sp. gravity g/cm 3

oil absorp. %

Moisture %

Acid soluble

hardness water soluble

Limestone sample 1 Limestone sample 2 Limestone sample 3 Limestone sample 4

2.70 2.69 2.72 2.70

33 32 36 34

0.05 0.06 0.05 0.07

8.5

99.0 99.0 98.0 98.5

3.0 0.96 3.0 0.86 3.0 0.95 3.0 0.93

9 8 9

Table 5 Chemical compositions of limestone at some localities of El Minia.

Ore Type

Chemical composition CaO

Al2O3

Fe2O3

MgO

H20

L.O.I

Limestone sample 1 Limestone sample 2 Limestone sample 3 Limestone sample 4

55.61 55.70 55.56 55.67

0.11 0.14 0.10 0.11

0.12 0.16 0.07 0.13

0.07 0.11 0.13 0.11

0.20 0.11 0.10 0.10

43.80 43.70 43.75 43.80

(a) Grinding machine of limestone

(b) Final product of grind limestone

Fig. 4. (a) Grinding machine of limestone (b) Final product of grind limestone.

4.6. Hydrogen ion concentration (pH value)

The pH test carried out to collected sample as per [17] to mea- sure the value of alkaline or acidity of carbonate powder and the results shows that pH is 8.5%, it means the pH range is alkaline.

4.7. Matter soluble in water

The carbonate powder pigment shall be insoluble in water, except traces of soluble salt. The test result indicates that the amount of soluble matter is 0.4%, meanwhile the standard limit as per [18], shall be not exceed than 1% as shown in Table 4.

4.8. Moh’s hardness

The hardness of carbonate powder utilized in paper filler and coating is most important for the paper product and production equipment (wear on wire, doctor and slitter wearing), the lime- stone studied samples hardness is 3 as per Moh’s scale (1: talc to 10: diamond).

Fig. 5. Particle Size Distribution.

4.5. Particle shape

4.9. Appearance & Color of powder

Particle shape and size influence on the properties of carbonate powder pigment such as consistency, oil absorption, hiding power of paper coating and filler, the carbonate examined grain shape is rounded and sub round.

The color of ore powder is useful in identify the pigment into white or colored pigment, however the history of mineral forma- tion. The visual inspection of limestone sample is milky white to white due to high purity of calcium carbonate content.

M.A.W. Gaber / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

4.11. Purity as CaCO3: 95%

The CaCO3 content in studied samples are ranging from 99.30 to 99.65%, which called high purity limestone as per [19].

4.12. Refractive index

Refractive Index is the difference between the speed of light in a vacuum and the speed of light in the gemstone. As light passes through a gemstone, it slows down because a gemstone is denser than air. The angle of refraction in the gemstone determines its RI [20]. The RI is easily measured using a refractometer. Limestone fillers are mainly composed of strongly birefringent calcite mineral with refractive indices ranging from 1.49 to 1.65.

4.13. Specific surface area

Specific surface area is measured by the nitrogen adsorption method (BET: Brunauer, Emmet, Teller). The particle fineness, the particle size distribution, and the particle morphology are, depend- ing on the structure, indirectly reflected in the specific surface area of the filler. Finer, non-structured fillers exhibit a higher specific surface than coarser ones. There is, a direct correlation between the specific surface area of filler and, the internal sizing agent demand. An internal sizing agent is applied to the wet end in order to make the paper more hydrophobic. The specific surface area of regular paper fillers ranges between 2.5 and 14 m 2 /g 1 , while fiber fines show specific surface areas of 6–8 m 2 /g 1 . The surface area

Fig. 6. Brightness of El Minia carbonates.

4.10. Brightness of El Minia calcium carbonate

In paper industry the high dry brightness is preferred to pro- duce the high quality paper. The limestone were crushed to very fine size and tested using Dr. Lange equipment (Fig. 6), and the results achieved the requirements of paper making brightness value ranging from 91 to 93.5% as shown in Table 3.

(a) SEM for El Minia limestone

(b) SEM for el Minia Chalk

Fig. 7. (a) SEM for El Minia limestone (b) SEM for el Minia Chalk.

C o un ts

Dr.M.Abdel-Wahab (12)

1 5 0 0

1 0 0 0

5 0 0

1 0

2 0

3 0

4 0

5 0

6 0

Position [°2Theta] (Copper (Cu))

Fig. 8. XRD of Limestone at Samalout area.

M.A.W. Gaber / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

for calcium carbonate powder ranging from 2 to 12 m 2 /g- 1 as per [21].

brightness chalk is used as filler in the production of regular newsprint.

4.14. Scanning electron microscope (SEM)

4.15. Chemical analysis

The structure of fillers can be observed and characterized best by scanning electron microscopy (SEM). The particle morphology has an influence on light scattering via the number and size of air microvoids in the sheet. For different morphologies, there is a different optimum for light scattering in terms of particle size. The particle morphology has an impact also on the packing of the filler particles in the flocculates usually formed during the papermaking process. The crystallite habit of natural ground CaCO3 filler is rhombo- hedral Fig. 7. For high brightness demand, GCC fillers based on limestone and marble are preferred by the paper industry. Lower

The XRF analysis of collected limestone revealed that the major element is CaO 55.70; accordingly the CaCO3 is 99.65% as indicated in Table 5. These results reflect that the studied ore possess high purity and suitability for industrial proposes and paper making.

4.16. X-Ray diffraction

Four samples were analyzed by XRD and the data of identified minerals of powder samples were plotted in the following diagrams:

Counts

Dr.M.Abdel-Wahab (13)

1000

500

Position [°2Theta] (Copper (Cu))

Fig. 9. XRD of Samalout Limestone.

C o unts

Dr.M.Adbel-Wahab (1)

15 0 0

10 0 0

5 0 0

1 0

2 0

4 0

5 0

6 0

Position [°2Theta] (Copper (Cu))

Fig. 10. X-ray diffraction of Beni Khalid carbonate.

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