Thermal plasma technology and waste vitrification

The thermal plasma is essentially constituted from an overall neutrally ionized, high-temperature gas (> 4,000-5,000 °C), composed of positive, negative, neutral ions found in an excited state. These special characteristics make the thermal plasma particularly suitable for various applications, including the treatment of hazardous waste, for which this technology has been incorporated into the list of BAT.

The extremely high temperatures allow the melting and encapsulation in a glassy matrix (waste vitrification) of dangerous inorganic components; at the same time, the organic components become gaseous and transform into simpler molecules, while the source eliminates the possibility of forming dioxins and furans.

Ecotec's Research Centre has created a pilot plant with a mid-scale thermal plasma reactor, in order to test the plasma arc technology transferred on a wide variety of waste materials. Thanks to this thermal plasma plant, suitable processes can be identified to transform some types of materials (otherwise hardly treatable or disposable with other technologies) in waste disposable at the landfill, thanks to waste vitrification; the thermal plasma technology also makes it possible to extract specific substances from waste that can be transformed in materials with high added value that can be reinserted in the economic cycle.

The study of the geometry of the reactor, the preliminary analysis of the sample that is going to be treated, the ability to operate with different process gasses, as well as the ability to create special chemical-physical conditions in the reaction chamber, guarantee the right versatility of the thermal plasma system to treat almost any type of hazardous waste, possibly after any pre-treatment processes. Furthermore, in many cases, exploitable substances or elements can be extracted from hazardous waste or particularly complex matrices using more complex processes in order to be re-introduced in target markets.
The Ecotec Research Centre also has a small non transferred arch-type thermal plasma reactor (plasma torch) particularly effective in the treatment of liquids and gases. The gas used by the plasma torch is generally the argon; this way, by using mass spectroscopy, the occurring reactions and present ions can be monitored during the reaction. Thanks to these controls, the stoichiometry of the reactions can be oriented towards specific products, with a high degree of accuracy.

Although Europe and the rest of the world currently have only a small number of pilot plants that take advantage of the thermal plasma technology for the treatment of hazardous waste (processes falling into the categories of "plasma pyrolysis waste-treatment" or "plasma waste vitrification"), they are spreading with great rapidity, thanks to treatment effectiveness of these types of waste.

The Research Centre's pilot plants, which are unique in Italy, are available for companies/entities that intend to develop new processes for the treatment of industrial waste, especially related to the replacement of traditional technologies that are now obsolete for the exacerbation of sector legislation.

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