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Ash recycling technologies

Objective

To investigate some new alternatives in the field of reclycling of fly ashes from urban solid waste, to assess their environmental impact, to identify the possible final building products, to compare the relative advantages and disadvantages of the different approaches.

A project has been set up to study the reuse of waste incineration fly ashes as construction materials with safe and stable behaviour and avoiding environmental concern. Likewise, the reuse of lead containing glass from fluorescent lamps for foam glass production. The objective was to supply decision making elements as to the most suitable recycling process, taking into consideration technical, economic and social aspects.

One technical aspect developed was a process to transform incinerator ashes directly into components for civil construction (eg paving stones). Ash generated fibres were produced which have a greater alkali resistance than standard E-type glass fibres. A good traction resistance was also displayed. Foam glass was obtained by recycling of fluorescent lampas and cathode ray tubes. A process for detoxification was developed. The glass showed a lighter load and lower bulk density relative to granule size than normal recycled glass.
A thermal process has been developed for the sinterization of pellets consisting of municipal solid waste (MSW) ashes and other wastes such as steel work dusts and coal fly ashes. Samples have been obtained for characterization tests. A method which recycles MSW to produce a material similar in quality and properties to lightweight concrete is under development. Chemical, physical and environmental tests have been carried out on various materials produced from MSW fly ashes. Work has been undertaken on the possibilities for stabilizing and utilizing industrial rest materials ashes, dusts, slurries etc, to produce binder materials.
An investigation has been carried out of the MSW incineration methods adopted in different European countries. Legal constraints on MSW fly ash recycling have been studied.
Three technological routes will be examined :

i) Combination of fly ashes with hydraulic binders, based on silica to obtain special aggregates for concrete.

ii) Production of "gres" material in form of sinterized pellets, to obtain aggregates for concrete and bitumen.

iii) Spinning of fly ash mixtures in form of thin fibers, to be used in lime, concrete and bitumen composites.

A fourth specific task will be devoted to the recycling of exhausted fluorescent, energy saving, high pressure, and cathode ray tubes, that cannot be mixed up with standard recycled glass due to their high heavy metal content. Recycling processes for these materials can be put in connection with fly ash recycling, considering the chemical composition and environmental concerns. The possible production of foam glass will be specifically investigated.

Coordinator

CONPHOEBUS SCRL - ISTITUTO DI RICERCHE PER LE ENERGIE RINNOVABILI E IL RISPARMIO ENERGETICO
Address
Passo Martino Zona Industriale
95030 Catania, Piano D'arci
Italy

Participants (4)

ANSALDO RICERCHE SPA*
Italy
Address
Corso Perrone 25
16152 Genova
Centre Expérimental de Recherches et d'Etudes du Bâtiment et des Travaux Publics (CEBTP)
France
Address
Domaine De Saint-paul
78470 Saint-rémy-lès-chevreuse
Physik und Datentechnik GmbH
Germany
Address
Heroldsberger Weg 5
90411 Nürnberg
Rheinisch-Westfälische Technische Hochschule Aachen (RWTH)
Germany
Address
Mauerstraße 5
52064 Aachen