Using of Magnesium Hydroxide and Sodium Hydroxide in DP Beaching of NaOH-AQ Wheat Straw Pulp

2013 ◽  
Vol 690-693 ◽  
pp. 1455-1460
Author(s):  
Wen Bo Wang ◽  
Fan Gong Kong ◽  
Shou Juan Wang ◽  
Ya Jie Zhong ◽  
Gui Hua Yang
Keyword(s):  
Tensile Strength ◽  
Sodium Hydroxide ◽  
Wheat Straw ◽  
Magnesium Hydroxide ◽  
Chlorine Dioxide ◽  
Control Agent ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Wheat Straw Pulp ◽  
Pulp Properties

Sodium hydroxide (NaOH) substituted by magnesium hydroxide (Mg(OH)2) as control agent and alkali source were investigated in chlorine dioxide bleaching and hydrogen peroxide bleaching of NaOH-AQ wheat straw pulp. The effects of alkali sources on pulp properties, including brightness and tensile strength, were investigated. The four experimental groups, including DNaOHPNaOH, DNaOHPMg(OH)2, D Mg(OH)2PNaOH and DMg(OH)2PMg(OH)2, were studied in this paper. The results showed that the brightness and tensile strength of DMg(OH)2PMg(OH)2 pulp was slightly lower than that of DNaOHPNaOH pulp. But there were more residual ClO2 and residual H2O2 in the effluents of DMg(OH)2PMg(OH)2 bleaching process than that in the effluents of DNaOHPNaOH bleaching process, which illustrated that DMg(OH)2PMg(OH)2 bleaching process had higher bleaching efficiency than DNaOHPNaOH bleaching process. The influence of Mg(OH)2 replacing NaOH was more obvious when it was used in the bleaching process of P stage than that in the D stage. The replacement of NaOH with Mg(OH)2 in D Stage can lower the dosage of alkali used in the following P stage.

Review: Using magnesium hydroxide as the alkali source for peroxide bleaching of mechanical pulps - process chemistry and industrial implementation

2010 ◽  
Vol 25 (2) ◽  
pp. 170-177 ◽  
Author(s):  
Yonghao Ni ◽  
Zhibin He
Keyword(s):  
Sodium Hydroxide ◽  
Magnesium Hydroxide ◽  
Paper Industry ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Industrial Implementation ◽  
Process Chemistry ◽  
Peroxide Decomposition ◽  
Mechanical Pulps ◽  
Pulp Properties

Abstract Magnesium hydroxide, which is a weak alkali, can be used as the alkali source for peroxide bleaching of mechanical pulps. This magnesium hydroxide-based peroxide bleaching process has been commercialized in the paper industry. In this paper, we review the literature results regarding the process chemistry of the Mg(OH)2-based peroxide bleaching process, including the kinetics, peroxide decomposition, anionic trash/COD/oxalate formation, the effect on pulp properties. The benefits associated with the Mg(OH)2- based peroxide bleaching process are discussed. We also discuss the mill implementation of the Mg(OH)2- based peroxide bleaching process in the pulp and paper industry. A case is presented where magnesium hydroxide completely replaces sodium hydroxide as the alkali source. A partial magnesium substitution for sodium hydroxide can also be an option.

Study on Xylanase-Aided Bleaching of Wheat Straw KP

2013 ◽  
Vol 726-731 ◽  
pp. 548-551
Author(s):  
Li Jun Zhao ◽  
Mei Hong Niu ◽  
Jian Zhang ◽  
Yan Ning Sun ◽  
Na Li
Keyword(s):  
Hydrogen Peroxide ◽  
Wheat Straw ◽  
Oxygen Pressure ◽  
Treatment Time ◽  
Optimal Concentration ◽  
Experimental Results ◽  
Peroxide Bleaching ◽  
Wheat Straw Pulp ◽  
Pulp Properties ◽  
Oxygen Bleaching

Before oxygen bleaching and hydrogen peroxide bleaching, wheat straw pulp was bleached using xylanase. The effect of enzymatic stage on pulp properties and bleachability has been studied and compared with reference (control) pulps, processed without enzyme addition. Experimental results showed that, the optimal concentration of wheat straw pulp was 10%, the optimal treatment time and dose of enzyme was 60 min and 1.25AXU/g respectively. Oxygen pressure decreased from 0.6MPa to 0.5MPa when conditions of hydrogen peroxide bleachingremained unchanged and wheat straw pulp achieved the same whiteness. Hydrogen peroxide consumption decreased from 2% to 1.8% when oxygen bleaching has the same conditions and achieved the same white degree.

Environmental benefits of magnesium hydroxide-based peroxide bleaching of mechanical pulp – mill results

TAPPI Journal ◽  
2013 ◽  
Vol 12 (6) ◽  
pp. 9-15 ◽  
Author(s):  
TOMI HIETANEN ◽  
JUHA TAMPER ◽  
KAJ BACKFOLK
Keyword(s):  
Sodium Hydroxide ◽  
Magnesium Hydroxide ◽  
Oxygen Demand ◽  
Pulp Mill ◽  
Transition Metal Ions ◽  
Environmental Benefits ◽  
Raw Material ◽  
Paper Machine ◽  
High Brightness ◽  
Peroxide Bleaching

The use of a new, technical, high-purity magnesium hydroxide-based peroxide bleaching additive was evaluated in full mill-scale trial runs on two target brightness levels. Trial runs were conducted at a Finnish paper mill using Norwegian spruce (Picea abies) as the raw material in a conventional pressurized groundwood process, which includes a high-consistency peroxide bleaching stage. On high brightness grades, the use of sodium-based additives cause high environmental load from the peroxide bleaching stage. One proposed solution to this is to replace all or part of the sodium hydroxide with a weaker alkali, such as magnesium hydroxide. The replacement of traditional bleaching additives was carried out stepwise, ranging from 0% to 100%. Sodium silicate was dosed in proportion to sodium hydroxide, but with a minimum dose of 0.5% by weight on dry pulp. The environmental effluent load from bleaching of both low and high brightness pulps was significantly reduced. We observed a 35% to 48% reduction in total organic carbon (TOC), 37% to 40% reduction in chemical oxygen demand (COD), and 34% to 60% reduction in biological oxygen demand (BOD7) in the bleaching effluent. At the same time, the target brightness was attained with all replacement ratios. No interference from transition metal ions in the process was observed. The paper quality and paper machine runnability remained good during the trial. These benefits, in addition to the possibility of increasing production capacity, encourage the implementation of the magnesium hydroxide-based bleaching concept.

The Effect of Microwave Treatment on the Hydrogen Peroxide Bleaching of Soda-AQ Wheat Straw Pulp

2011 ◽  
Vol 236-238 ◽  
pp. 1307-1312
Author(s):  
Chao Jun Wu ◽  
Chuan Shan Zhao ◽  
Jun Li ◽  
Ke FU Chen
Keyword(s):  
Hydrogen Peroxide ◽  
Wheat Straw ◽  
Fiber Length ◽  
Weighted Average ◽  
Microwave Treatment ◽  
Arithmetic Average ◽  
Peroxide Bleaching ◽  
Bleached Pulp ◽  
Infra Red ◽  
Wheat Straw Pulp

In this paper, the effect of microwave treatment on the hydrogen peroxide bleaching of Soda-AQ wheat-straw pulp was investigated. The results showed that microwave treatment could increase the brightness of the hydrogen peroxide bleached pulp. The fiber coarseness of microwave enhancing peroxide bleached pulp was higher than that of the peroxide bleached pulp. However, the arithmetic average fiber length, the length weighted average fiber length and weight weighted average fiber length of the former was lower than that of the latter. Fourier transform infra-red spectroscopy (FTIR) and X-ray diffraction (XRD) spectra showed that CrI(%) crystallinity of microwave enhancing peroxide bleached pulp was similar as that of the peroxide bleached pulp but all higher than that of the Soda-AQ wheat-straw pulp. N·O′KI infra-red crystalline index of microwave enhancing peroxide bleached pulp were lower than that of the peroxide bleached pulp. The FTIR spectra of lignin showed that the microwave treatment had some influences on the methoxyl and phenolic group in lignin.

Study on Magnesium Hydroxide-Based Hydrogen Peroxide Bleaching Process of Nigra poplar CTMP

2011 ◽  
Vol 233-235 ◽  
pp. 1328-1331 ◽  
Author(s):  
Qiang Zhao ◽  
De Zhi Sun ◽  
Ming Yang Zhang ◽  
Su Min Kang
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Magnesium Hydroxide ◽  
High Yield ◽  
Pulp Yield ◽  
Pulp Bleaching ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Bleaching Condition ◽  
Pulp Consistency

The Mg(OH)2-based peroxide bleaching process of Nigra poplar CTMP pulp was confirmed. The optimal bleaching condition were as follows: 4% H2O2,1% Mg(OH)2, 15% pulp consistency, the reaction temperature was 80°C and the suitable reaction time was 2 hours. The Mg(OH)2-based bleaching process shows significant benefits over sodium hydroxide process. In contrast, magnesium hydroxide bleaching generates higher pulp yield and lower effluent COD at the same chemical dosage. The study shows peroxide bleaching of CTMP pulp with magnesium hydroxide as alkali source is to be an option for the high-yield pulp bleaching.

Improvement of bleached wheat straw pulp properties by using aspen high-yield pulp

2012 ◽  
Vol 120 ◽  
pp. 40-44 ◽  
Author(s):  
Hongjie Zhang ◽  
Jianguo Li ◽  
Huiren Hu ◽  
Zhibin He ◽  
Yonghao Ni
Keyword(s):  
Wheat Straw ◽  
High Yield ◽  
Wheat Straw Pulp ◽  
Pulp Properties

scholarly journals Effects on Pulp Properties of Magnesium Hydroxide in Peroxide Bleaching

BioResources ◽  
2013 ◽  
Vol 8 (2) ◽  
Author(s):  
Tomi M. Hietanen ◽  
Monika Österberg ◽  
Kaj A. Backfolk
Keyword(s):  
Magnesium Hydroxide ◽  
Peroxide Bleaching ◽  
Pulp Properties

Improvement of Wheat-Straw Pulp Properties with an Alkali-Tolerant Xylanase fromPseudomonassp. G6-2

1996 ◽  
pp. 308-316 ◽  
Author(s):  
Jiachuan Chen ◽  
Jianyun Yang ◽  
Yinbo Qu ◽  
Peiji Gao ◽  
Baomin Wang ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Wheat Straw Pulp ◽  
Pulp Properties

The Role of Ferulic Acid Removal during Bleaching of Wheat Straw Mechanical Pulp with Peroxygen Reagents

Holzforschung ◽  
2003 ◽  
Vol 57 (3) ◽  
pp. 282-288 ◽  
Author(s):  
G. X. Pan ◽  
C. I. Thomson ◽  
G. J. Leary
Keyword(s):  
Ferulic Acid ◽  
Wheat Straw ◽  
Model Compounds ◽  
Mechanical Pulp ◽  
Peroxide Bleaching ◽  
Wheat Straw Pulp

Summary The present paper reports our investigation into the use of two peroxygen reagents, peroxymonosulfate (PMS) and dimethyldioxirane (DMD), in bleaching sequences with peroxide to bleach wheat straw mechanical pulp, their reactivity with ferulic acid model compounds, and the likely relation between the two aspects. It was observed that combinations of PMS or DMD with peroxide offered a synergy leading to substantially improved brightness development in bleaching of wheat straw pulp. At the same time, these oxidizing reagents, especially DMD, were shown to be highly reactive with ferulic acid derivatives and increased the removal of ferulic acid from wheat straw pulp in bleaching. The results would suggest that the presence of non-lignin, peroxide-resistant chromophoric components, such as ferulic acid derivatives, might be an important factor limiting the brightness development of wheat straw mechanical pulp by conventional peroxide bleaching.

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