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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 .
Chlorine dioxide is sometimes used in combination with chlorine, but it is used alone in ECF (elemental-chlorine-free) bleaching sequences. It is used at moderately acidic pH (3.5 to 6). The use of chlorine dioxide minimizes the amount of organochlorine compounds produced. [8]
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 ...
The most popular method now is elemental chlorine free (ECF) bleach — which, despite its name, emits chlorine gas containing dioxins into the air and water near tissue manufacturing plants; it's ...
For example, Melitta uses up to 60% of bambus in their filters since 1998. [3] Both bleached and unbleached qualities are made. [1]: 114 Coffee filters are made in different shapes and sizes to fit into different holders. Most notable are the (paper) coffee filter systems introduced by Melitta (1908, 1932, 1936, 1965), Chemex (1941) and Hario ...
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.
As with the charts, the bars have to be especially resistant to corrosion because of the corrosive nature of some coatings. [4] There are a multiplicity of more complicated designs including some in which the paint is already in the chart apparatus, but the bar method described above is the most commonly used.
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