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

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.

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.

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.

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.

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.

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

Comprehensive evaluation of kraft pulp properties from fast-growing woods

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 34-39
Author(s):  
AIYU QU ◽  
YANHUI AO ◽  
JUN YAN ◽  
GUIGAN FANG
Keyword(s):  
Kraft Pulp ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Evaluation Index System ◽  
Evaluation Index ◽  
Wood Cellulose ◽  
Fuzzy Matrix ◽  
Fast Growing ◽  
Pulp Properties ◽  
Evaluation Index Systems

To develop new wood cellulose resources and fast-growing pulpwood plantation fiber sources, it is very important to evaluate their pulping properties. A comprehensive multi-index pulping-suitability evaluation model is investigated in this paper by considering four fast-growing wood species. First, a new evaluation-index system for kraft pulp was developed based on traditional evaluation-index systems. Then, the membership degree of every index was analyzed to obtain a fuzzy matrix. The proportional contribution of each parameter to the main pulping properties could then be determined. Finally, a comprehensive evaluation model of kraft pulp properties was developed. The model is reliable compared with traditional assessment methods. The results confirmed the feasibility and rationality of developing new wood cellulose resources and fast-growing pulpwood plantations using fuzzy comprehensive evaluations.

Refining Energy Reduction and Pulp Characteristic Modification of Alkaline Peroxide Mechanical Pulp (APMP) Through Enzyme Application

TAPPI Journal ◽  
2009 ◽  
Vol 8 (5) ◽  
pp. 19-25 ◽  
Author(s):  
PETER W. HART ◽  
DARRELL M. WAITE ◽  
LUC THIBAULT, ◽  
JOHN TOMASHEK ◽  
MARIE-EVE ROUSSEAU ◽  
...  
Keyword(s):  
Wood Chip ◽  
The United States ◽  
Enzyme Treatment ◽  
Chemical Application ◽  
Alkaline Peroxide ◽  
Eucalyptus Wood ◽  
Pulp Properties ◽  
Pulp Processing ◽  
Two Stages ◽  
Enzyme Application

Eucalyptus wood chips were subjected to impregnation with various blends of novel fiber modify-ing enzymes before chemical pretreatment and two stages of refining using the preconditioning refiner chemical–alkaline peroxide mechanical pulping (PRC-APMP) process. Wood chip impregnation and pulp processing was con-ducted at a pilot plant in the United States. When compared under constant chemical application and at a constant 350 mL CSF, enzyme treatment reduced specific refining energy by at least 24%. The effect of one versus two stages of impregnation and of enzyme action upon several physical pulp properties was determined.

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