Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Processing of awkward by-products through the ZEWA process - Study of the availability of complementary materials / by-products as input materials for the ZEWA process

The study of the availability of complementary materials and by-products as input materials for the ZEWA process gives an overview of considered materials (mainly acidic by-products from other activity sectors), including availability and economic aspects (mainly cost).

Fly ash is considered as the main acidic input material, with the advantages of availability in large quantities at various locations, of generally poor valorisation. An additional benefit is found in the use of fly ash qualities with high carbon contents, which are unusable for cement production but beneficial for the ZEWA process.

Lafarge provided a detailed information on typical fly ash qualities in several European countries were Lafarge is present (Austria, Spain, Turkey, etc), at various locations (power stations using different coal qualities), including variability with time. ICPC also supplied information, mainly for Eastern European countries. This contributed to assess the feasibility of the process (case studies for process implementation) and to evaluate the interest of the other acidic alternatives (silica carriers). These alternatives include the processed scrap residues (see the first project result), processed shredder residues, bottom incinerator ash and various sands (including foundry sand). Processed shredder residue stands for the mineral fraction of the light residue from car dismantling supplied by Cometsambre. This material does not justify erecting a dedicated ZEWA plant, but could be supplied for processing in any such plant erected in reasonable proximity. Other materials (bottom incinerator ash, foundry sands, etc) can also be used as silica-carriers, depending on local availability and costs.

This study also included other secondary complementary materials such as alumina dross (used as alternative strong reductant), ferrous bauxite (used when necessary to increase the alumina content of the produced slag).

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