Metals as Catalysts for Dioxin Formation

Certain metals act as catalysts for dioxin formation, providing a surface upon which dioxins can readily form. This generally occurs during and after combustion processes on the fly ash in boilers and incinerators, but can also occur in other environments, such as in metals processing industries.

Copper (Cu) is the most potent catalyst for dioxin formation, but Iron (Fe), Zinc (Zn), Potassium (K) and Sodium (Na) have also been found in multiple studies to be correlated with increased dioxin/furan formation. Some studies have also indicated that Manganese (Mn), Magnesium (Mg) and Nickel (Ni) may also serve as catalysts for dioxin formation. Studies have conflicted on whether Aluminum (Al) encourages or inhibits dioxin formation. One study below indicated that Silicon (Si) is negatively correlated with dioxin formation.

The metal catalyst issue is the likely reason why secondary copper and aluminum smelters are among the largest known sources of dioxin pollution in the U.S. Copper electrical wiring, coated with chlorine-containing PVC plastic is a perfect recipe for dioxin formation, when homes and buildings burn, when the plastic-coated wire gets burned in an incinerator, or when any of this plastic or its residues get into a secondary copper smelter.

Other sources of dioxin pollution include metal-related industries with high temperature processes, such as iron ore sintering in the steel industry, aluminium recycling, copper ore melting, nickel refining, magnesium production, electrical cable splicing, and catalyst regeneration in the petroleum refining industry. [Kobylecki]

Dioxin/furan formation during any natural or human activity requires three basic ingredients: an organic starting material, a chlorine source, and, in processes with relatively low temperatures, a metallic catalyst. [Kobylecki]

Primary Research:

Other sources citing the metal catalyst issue:

Catalyzed Precursor Mechanisms

Effects of various metals on dioxin formation from chlorinated phenol

Chart of Dioxin Catalysts

Last modified: 29 December 2003

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