Glossary of Pulp Production Terms

AOX/adt: Absorbable Organic Halogen per average daily ton of pulp produced. Halogens are a family of elements chlorine, fluorine and bromine which have similar physical structures and behave similarly when they make compounds (eg. they are all ozone depleting substances). AOX is determined by absorbing organochlorines present in the sample on activated charcoal, which is then burnt and analysed for chlorine content.

Bioaccumulation: Storage in the tissue of animals of higher concentrations of a chemical which is found in the environment or in food.

Chlorine: Chlorine gas (elemental chlorine) is produced through the electrolysis of salt water, a process first designed to turn salt water into table salt. Originally an unwanted by-product of the salt making process, the sheer volume of chlorine gas created meant that uses for it must be found. These include pulp bleaching, plastics and pesticide manufacture, domestic and industrial bleach, and chemical warfare.

Chlorine dioxide: A highly volatile compound of chlorine and oxygen, used to bleach pulp, which creates less dioxin than elemental chlorine alone.

Delignification: Removal of lignin from wood fibres. ECF pulp mills use chlorine compounds for this process, although it can be achieved with oxygen, hydrogen peroxide or ozone (which do not create organochlorines) or with extended cooking of wood chips and/or better washing of the pulp before bleaching.

Dioxin: The most toxic organochlorine, dioxins are the unavoidable, unwanted by-product of industrial processes which involve the use of chlorine (including the manufacture of pulp, some plastics and many pesticides) and the burning of chlorine-contaminated wastes. A known carcinogen, dioxin is now implicated in numerous developmental, immunological and reproductive failures in humans and wildlife.

ECF (Elemental Chlorine Free): Pulp bleached with chlorine dioxide or other chlorinated compounds, which does not use elemental chlorine gas.

Effluent: Waste water discharged during a manufacturing process.

ISO: International Standards Organization index of whiteness. High brightness market pulp has a whiteness of ISO 90 and above; integrated mills generally bleach pulp to around ISO 85. Newsprint has a brightness of around ISO 6570.

Lignin: A glue-like substance (resins, acids, sap, etc) which provides structural support in trees. It must be washed out of the cellulose fibres to make the pulp from which paper is manufactured.

Organochlorines (chlorinated organics): An organic compound, composed of carbon and hydrogen, which also contains the element chlorine. Some organochlorines, including dioxins and furans, are persistent and toxic; others appear to be benign. When the carbon is bonded into a benzene ring, the organochlorine is particularly persistent, because the basic ring of carbon is very stable. PCBs, DDT and 2,4,5-T are organochlorines often mentioned in the news.

Sludge: Solid waste created during a manufacturing process.

TCF (Totally Chlorine Free): Pulp bleached without the use of any chlorine compounds, i.e. no chlorine dioxide, chlorine gas or hypochlorite is used in the bleaching sequence.

 

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