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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 .
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 ...
As a result, from the 1990s onwards, the use of elemental chlorine in the delignification process was substantially reduced and replaced with ECF (elemental chlorine free) and TCF (totally chlorine free) bleaching processes. In 2005, elemental chlorine was used in 19–20% of kraft pulp production globally, down from over 90% in 1990. 75% of ...
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".
In the past, plants using elemental chlorine produced significant quantities of dioxins, [35] persistent and very toxic organic pollutants. From the 1990s onward, the use of elemental chlorine in the delignification process was substantially reduced and replaced with ECF (Elemental Chlorine Free) and TCF (Totally Chlorine Free) bleaching processes.
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Chlorine-releasing compounds, also known as chlorine base compounds, is jargon to describe certain chlorine-containing substances that are used as disinfectants and bleaches. They include the following chemicals: sodium hypochlorite (active agent in bleach ), chloramine , halazone , and sodium dichloroisocyanurate . [ 2 ]
Bleaching trays, also called whitening trays, are made from a pliable material that molds to your teeth. Some products come preloaded with bleaching gel, while others require you to add the gel ...