Pulp and paper industry refers to perspective sectors of Russian economy and introducing the cycle of enclosed water consumption is necessary to solve ecological problems on enterprises. It can be accomplished only with Total Chlor Free-bleaching (under a total absence of chlorous substances). Transition towards TCF-bleaching on the existing equipment is possible under the function of technological system with one stage of bleaching with chloric dioxide (soft ECF-bleaching) and its minimum consumption, for example, no more than 0,5 % of sulfate pulp (E.I. Fedorova, A.V. Kuzivanova Patent of RF № 2413046. A method of bleaching sulfate pulp). Implementation of monosaccharides besides oxidants is possible during TCF-bleaching of pulp (as they have a reducing impact on structures of residual lignine), one can use arabinose, considering high contents of arabinogalactane in larches that are used to receive arabinose. Studies of schemes of processing deciduous sulfate pulp that include oxygenic-neutrolizing procession (solidity 11,7 units of kappa) and high-temperature procession with acid have been carried out. The following stages include bleaching pulp: Н2О2 under рН 10−10,2 with stabilizer (solidity 6 units of kappa, pulp whiteness 75 %), arabinose, and hydrogen peroxide. However, implementation of monosaccharides in bleaching pulp is limited by their impact over certain structures of residual lignine (O.V. Lepilova Foundation of enzymatic methods of regulated slitting of carbohydrate additives and delignification of linen sliver: author’s abstract on dissertation of candidate of technical science, – Ivanovo, Institute of solutions’ chemistry of Russian academy of science, 2007, 19 p.) Therefore, whiteness index for deciduous pulp in acid environment equaled only 83 % under viscosity index 740 ml/g that is acceptable in producing paper, when ecological factor plays the most important part. Besides, acid filtrates of bleaching sulfate pulp according to the developed scheme should be directed to areas of boiling in order to scour pulp, and then further to the system of alkali liquor regeneration. Absence of chloride ions in neutralizing filtrates of bleaching implies their secondary implementation after local cleaning with ozonation, and contents of phenols in them should be decreased down to 86 % and lower, depending on the continuity of this process.
The work is submitted to the International Scientific Conference «Ecology of industrial regions of Russia», Great Britain (London), 19-26 October 2013, came to the editorial office оn 27.09.2013.