A Kinetic Model of the Magnesium Hydroxide–Based Peroxide Bleaching Process of a TMP

2008 ◽  
Vol 28 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Huan Wang ◽  
Zhibin He ◽  
Yonghao Ni
Keyword(s):  
Kinetic Model ◽  
Magnesium Hydroxide ◽  
Bleaching Process ◽  
Peroxide Bleaching

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 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.

scholarly journals Kinetic study on iso-concentration hydrogen peroxide bleaching of poplar chemi-thermomechanical pulp by the process of continuous chemical supplement

BioResources ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. 5408-5415
Author(s):  
Xianqi Sun ◽  
Qingxi Hou ◽  
Haizhen Shi ◽  
Lichun Zhou
Keyword(s):  
Kinetic Model ◽  
Initial Phase ◽  
Reaction Rate ◽  
Reaction Order ◽  
Slow Phase ◽  
Thermomechanical Pulp ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Bleached Pulp ◽  
Continuous Chemical

In the authors’ previous studies, a bleaching process based on continuous chemical supplementation (CCS) was proposed to improve the effectiveness of peroxide bleaching of chemi-thermomechanical pulp (CTMP). In this study, the kinetic model of the CCS process of peroxide bleaching was applied to poplar CTMP to explore how the bleaching rate was affected. The model was based on the rate of chromophore elimination characterized by the brightness gains of bleached pulp. The reaction rate of chromophore destruction proceeded via a rapid initial phase followed by a slow phase. The equation of reaction rate was confirmed. The value of reaction order was -3.62, and the activation energy was 288.8 kJ/mol. The developed kinetic model was a good fit for the experimental results.

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.

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

Hydrogen Peroxide Bleaching to Wine Corks with a Novel Catalyst

2013 ◽  
Vol 734-737 ◽  
pp. 2282-2286 ◽  
Author(s):  
Li Liu ◽  
Shu Ling Cui
Keyword(s):  
Hydrogen Peroxide ◽  
Cork Stopper ◽  
Capillary Effect ◽  
Sewage Disposal ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Novel Catalyst

A novel catalyst CF-R for hydrogen peroxide bleaching to wine cork stopper was chosen to substitute the traditional imported item, and the corresponding bleaching process was studied. The influence of catalyst CF-R dosage, H2O2 concentration, bleaching temperature and time on cork whiteness and capillary effect were discussed. The optimized bleaching process for wine corks was obtained as follows: H2O2 concentration 14%, catalyst CF-R dosage 80g/L, bleaching temperature 70°Cand bleaching time 60 min. Comparing with the expensive imported catalyst, the amount of catalyst CF-R is greatly decreased, as is significant for not only cutting down the expenditure of chemicals, but also minimizing the burden on bleaching sewage disposal.

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