The Effect of Preheating Treatment and non-simultaneous Addition of Chemicals on the Efficiency of Hydrogen Peroxide Bleaching of Chemi-mechanical pulp(CMP)

Document Type : Research Paper

Authors

Abstract

In this research the effect of heating pretreatment and non-simultaneous addition of chemicalsin hydrogen peroxide bleaching of CMP pulps was investigated. Before the bleaching stage by hydrogen peroxide، Q stage was applied by means of removing transition metals from pulps by using of DTPA pretreatment under the same condition for all pulps. For this purpose, unbleached mixed hardwood CMP pulp was used. Hydrogen peroxide bleaching operation was done with three different procedures including: adding bleaching chemicals simultaneously, adding bleaching chemicals non-simultaneously and adding bleaching chemicals with heating pretreatment at two hydrogen peroxide levels of 2 and 3% and in NaoH/H2O2 proportions of 0.8 and 0.7 with 3% sodium silicate at 70˚C for 150min at 10% consistency level.
Results obtained from measuring optical and physical properties of handsheets showed that in all treatments at the same peroxide charge, non-simultaneous addition of chemicalswithpretreatment (process 3) caused better improvement in brightness and density of the paper. Also opacity، yellowness and caliper were lower in this process than the others. To reach a given brightness, hydrogen peroxide can be decreased. Therefore, by using the modified bleaching process we can economize on consumption of chemicals, by decreasing peroxide and alkali consumption at 1% and 23.8% to reach a given brightness. Also, COD load in this process at both levels of peroxide was lower than the other processes and therefore, it may decrease environmental contamination and effluent treatment requirement.

Keywords

References

1- Abrante s , Amaral E., Costa A.P., Shatalov A.A., Duarte A.P., 2007: Hydrogen  peroxide bleaching of Arundo donox L. Kraft-Anthraquinone pulp effect of a chelating stage، Industrial Crops and Products ,Vol.25:288-293.
2-APHA، Standard methods for examination of waterand Waste Water, 20th ed American Public Health Association/ American Water Works Assosiation/Water, Enviroment Federation, Washington DC,1998.
3-Bajpai P., 2005. Developments in environmental management, volume 1.Environmentally benign approaches for pulp Bleaching, Elsevier, PP.273.
4-Dyhr K, Sterte J., (1998). Effect of zeolite addition on the manganes catalyzed decomposition of hydrogen peroxide، Journal of Porous Materials، 6(4):275-282، Available from: http:// www.google scholar.com.
5-Haugan M, Solberg A.F, Gregersen O.W, 2006:  Hydrogen peroxide bleaching of different TMP fiber fractions, Journal of Pulp and Paper Science, Vol. 32(4):1-7.
6-Kang G.J, Ni Y, 2001. the formation of peracetic acid and its impact on peroxide bleaching of mechanical pulps، 11th International Symposium on wood and pulping chemistry, Nice, France, Book1, p.351.
7-Kong F, Ni Y, He Z, 2009. A partial magnesium hydroxide substitution for sodium hydroxide in peroxide bleaching of an Aspen CTMP، Journal of Wood Chemistry and Technology, 29(2):136-149.
8-Krishnan S, 2000 Improvement in Bleaching of mechanical pulps, M.Sc. Thesis، Department of Chemical Engineering, University of New Brunswick, 108 pages.
9-Lapierre L, 1995. Chelation prior to hydrogen peroxide bleaching of kraft pulps: An over view, Journal Pulp and Paper Science, Vol. 21(8): 268-273.
10-Major Daniella, Perrier Michel, Gendron Sylvain, Lupien Bernard, 2005. Pulp bleaching control and optimization, Department of Chemical Engineering.pp.13-18.
11-Ni Y, Li Z, Court G.، Belliveau R, Crowell M, 2003. Improving peroxide bleaching of mechanical pulps by the PM process، pulp and paper Canada journal, p.104:12.
12-Ni Y, Ju Y, Ohi H, 2000. Further understanding of the manganese-induced decomposition of hydrogen peroxide, Journal Pulp and Paper Science , Vol.29(3): 90-94.
13-Roberts J.C, The Chemistry of Paper، Translated by Mirshokraei S.A. and Sadeqifar H, 1381, aiij publication, Tehran, 184p (In Persian).
14-Scott W.A, Properties of paper: An introduction، Translated by Afrabandpay E, 1381، Agriculture Science Publication، Tehran، first ed. 392p (In Persian).
15-Technical Association of Pulp and Paper Industry، (2002). TAPPI Press، Atlanta.
16- Yu L, Rae M, Ni Y, 2004 . Formation of oxalate from the Mg(OH)2- based peroxide bleaching of mechanical Pulps, J. wood chemistry and technology, Vol.24(4):341-355
Iranian Journal of Wood and Paper Industries
Volume 1, Issue 2 - Serial Number 2
December 2011
Pages 27-36

Files

Share

How to cite

Statistics