A Comparison Between Alkali Peroxide and Activated Peroxide Processes in Bleaching Hardwoods Chemi-mechanical Pulp

Document Type : Research Paper

Authors

Abstract

Unbleached chemi-mechanical pulp of 85% pulp yield and produced from hornbeam, beech and populus woods respectively by 3:1:1 ratio, was used for peroxide bleaching. Two bleaching systems, alkali peroxide (conventional bleaching) and activated peroxide by TAED activator, were used for pulp bleaching. Bleaching treatments included different percentages of hydrogen peroxide and caustic soda consumption. In this research, the hydrogen peroxide consumption rate, pulp yield, process selectivity, bleached pulp brightness and bleaching effluent pollution load (COD) were investigated. Results showed that, brightness values were increased by bleach chemicals charge rising, in both bleaching systems, but the increasing trend was downward. Also, pulp yield was decreased by increase of chemical charges, but residual peroxide was raised. The activated peroxide process compare to conventional process had lower efficiency and brightness improvement values of pulp were less than those of alkali peroxide process. But pulp yield and effluent pollution load was less by activated peroxide bleaching.

Keywords


1- زینلی، ف.، دهقانی، م. و میرمهدی، م. 1388. رنگ­بریخمیرکاغذسودایپوستکنفبااستفادهازپراکسیدقلیایی، مجله پژوهش­های علوم و فناوری چوب و جنگل، 16(1): 105-113.
2- Bajpai, P. 2005. Environmentally Benign Approaches for Pulp Bleaching. In: Developments in environmental management, 1st edition, Elsevier, Amsterdam, Netherlands, 277 p.
3- Coucharriere, C., Mortha, G., Lachenal, D., Briois, L. and Larnicol, P. 2002. Rationalization of the use of TAED during activated peroxide delignification and bleaching. Part I: Kinetic Model. Journal of Pulp and Paper Science, 28(10): pp. 332-340.
4- Croud, V. and Mathews, J., 1996. TAED a new activator for the peroxide bleaching of pulp. In: Non Chlorine Bleaching Conference Orlando, p. 3.
5- Hsieh, J.S., Agrawal, C., Maurer, R.W. and Mathews J., 2006. The effectiveness of TAED on the peroxide bleaching of mechanical, chemical, and recycled pulp. Tappi Journal, 5(9): pp. 27-32.
6- Jaschinski, T. and Patt, R., 1998. Effects of polypyridines as peroxide activators in TCF bleaching of kraft pulps. In: Tappi Pulp Bleaching Conference Proceedings, p. 417.
7- Khristova, P., Tomkinson, J. and Lloyd Jones, G., 2003. Multistage peroxide bleaching of French hemp. Industrial crops and products 18: pp. 101-110.
8- Khristova, P., Tomkinson, J., Valchev, I., Dimitrov, I. and Lloyd Jones, G., 2002. Totally chlorine free bleaching of flax pulp. Bioresource Technology 85: pp. 79-85.
9- McGraw-Hill. Dictionary of chemistry. Second edition, USA, 431 p.
10- Pan, G.X., Spencer, L. and Leary, G.J., 2000. A comparative study on reactions of hydrogen peroxide and peracetic acid with lignin chromophores. Part 1. The reaction of coniferaldehyde model compounds. Holzforschung, 54(2): pp. 144-152.
11- Singh, R.P. 1991. The bleaching of pulp. TAPPI Press, Atlanta, U.S.A., 694 p.
12- Turner, N.A. and Mathews, A.J., 1998. Enhanced delignification and bleaching using TAED activated peroxide. Tappi Pulping Conference Proceedings, 1269 p.
13- Zeinaly, F., Shakhes, J., Dehghani, M. and Shakeri, A., 2009. Hydrogen peroxide bleaching of CMP pulp using magnesium hydroxide. Bioresources 4(4): pp. 1409-1416.
14- Zeinaly, F., Shakhes, J., Shakeri, A. and Zeinaly, N. 2011. Improving the bleaching process in CMP pulp from Mazandaran Wood & Paper Company. International Mechanical Pulping Conference 2011 (IMPC’11).