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Elemental chlorine free (ECF) is a technique that uses chlorine dioxide for the bleaching of wood pulp. It does not use elemental chlorine gas during the bleaching process and prevents the formation of dioxins and dioxin-like compounds , carcinogens .
In the 1990s ozone was touted as good reagent to allow pulp to be bleached without any chlorine-containing chemicals (totally chlorine-free, TCF). The emphasis has changed, and ozone is seen as an adjunct to chlorine dioxide in bleaching sequences not using any elemental chlorine (elemental-chlorine-free, ECF).
Elemental chlorine bleaching uses chlorine and hypochlorite. Elemental chlorine-free bleaching is more environmentally friendly since it eliminates the use of hypochlorite and replaces chlorine with chlorine dioxide or sodium chlorate. [3] Totally chlorine-free bleaching utilizes oxygen and hydrogen peroxide. This is the most environmentally ...
Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (process chlorine free) if no chlorine-containing compounds were used in the recycling process. [20]
Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (process chlorine free) if no chlorine-containing compounds were used in the recycling process. [73]
The grade of chlorine-based bleaches is often expressed as percent active chlorine. One gram of 100% active chlorine bleach has the same bleaching power as one gram of elemental chlorine. The most common chlorine-based bleaches are: Sodium hypochlorite (NaClO), usually as a 3–6% solution in water, usually called "liquid bleach" or just "bleach".
Jul. 9—Federal regulators announced Tuesday that Clearwater Paper Corp., based in Lewiston, has agreed to pay a fine for failing to properly report chlorine releases in 2019, 2020 and 2021.
Since dissolving pulp is highly refined, it is a product of high whiteness with few impurities making it suitable in specialty paper-related products such as filter paper and vulcanized fibre. Cellulose powder is dissolving pulp that has undergone acid hydrolysis, been mechanically disintegrated and made into fine powder.