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Pulp and Paper Science and Technology
 

 
Electrochemistry
 

Persulphate is a safe and stable peroxygen chemical which is made electrochemically from sulphate

Since 1988, Arbokem has improved the method to manufacture persulphate for the electrochemical bleaching of pulp. See following article:

 

Persulphate bleaching of softwood kraft pulp

A. Wong, S. Wu, C. Chiu and J. Zhao, Arbokem Inc., Vancouver, Canada

ABSTRACT. An efficient method has been discovered for the production of sodium persulphate. Conventional ClO2-based bleaching of kraft pulp has been found to be enhanced substantially with either the incorporation of persulphate stage into the bleaching sequence and/or the combined use of persulphate with ClO2.

Proc. CPPA/TS-TAPPI International Pulp Bleaching Conference, Vancouver, Canada, June, 1994; Pulp Paper Canada, 96: T236-239 (1995)
 

Adobe Acrobat Reader is required to view the entire pdf-formatted presentation. The software can be downloaded free from Adobe's web site.

 

In conventional pulp mills, pulp is bleached with chlorine dioxide and, invariably, a small amount of deleterious chlorinated phenolics is produced. This bleachery effluent is then subjected to biological treament. However, biological treatment is not completely effective in eliminating all the deleterious compounds. Some of the hazardous, cholorinated phenolics are discharged into the rivers and lakes. Persulphate provides a novel means to suppress the formation of these chlorinated phenolics during chlorine dioxide bleaching. Mill productivity was increased also.

Persulphate can be used beneficially with chlorine and/or hypochlorite for pulp bleaching or used singularly to afford totally chlorine-free bleaching.

We have invented new uses for persulphate in wood pulp bleaching and in the manufacture of market pulp from old corrugated containers. Persulphate is also used for deinking of wastepaper, bleaching of textiles, etc.
 


Persulphate trial at the Northwood pulp mill in Prince George in 1992

Arbokem's persulphate technology was practiced in a large-scale persulphate usage trial held at the Northwood pulp mill in Prince George in 1992. The results were :

No chlorinated organics in treated pulp mill effluent discharged into rivers, lakes and oceans.

Higher pulp mill productivity

Cleaner water for fish and other aquatic life

On July 28, 2004, the Northern Sentinel
in Kitimat reported on Arbokem's persulphate technology:

"Chemical plant proponent eyes Alcan power "

New-technology, economic opportunities in Northern British Columbia with Arbokem's persulphate technology

JOBS - 100 permanent, full-time jobs would be created

A brand new industrial demand for
" low-cost" power

There is no waste product except hydrogen gas
 

More publications

 

Persulphate enhancement of chlorine dioxide bleaching of softwood kraft pulp

Al Wong, Yi Feng, Chen Chiu and Stanley Wu, Arbokem Inc., Vancouver, Canada

ABSTRACT. Persulphate was found to be a particularly useful chemical for displacing chlorine dioxide in conventional bleaching of kraft softwood pulp. Applications which included using less ClO2 to achieve the same quality goal, enhancing conventional ClO2 bleaching, and replacing all ClO2 in TCF bleaching were investigated. There is a minimal danger of technology obsolescence with the adoption of persulphate bleaching technology in conventional bleached wood pulp mills. (AK19131W)

Proc. International Pulp Bleaching Conference, Halifax, Canada, June 27-30, 2000.