The District of Brescia is one of the largest in Italy, with over 1,200,000 inhabitants and an area of 4,784.36 km². Brescia stands out for the excellence of its manufacturing processes as well as for the application of the best available technologies for the reduction of environmental impacts.
In the CORALIS project, the Brescia industrial symbiosis (IS) network is related to the reuse and valorisation of by-products produced in a total of four companies in different metal sectors. Technologies, already studied and validated under relevant conditions, are currently used to demonstrate the feasibility of the collaborative scheme for transforming selected residues into raw materials for other industries or, eventually, for internal recycling. Residues from steel, cast iron and secondary aluminium production are exchanged to recover metal and drastically reduce their landfilling.
The demonstration activities include:
1) the design and installation of an energy self-sustained pyrolysis unit at Raffmetal aimed at the recovery of Al and the provision of the solid inert residue as reducing agent,
2) the installation of a prototype separation unit at Torbole for obtaining metal powder as alternative raw material and SiO2 as reducing agent,
3) the experimentation in a reducing furnace of a suitable company selected by Feralpi, in order to valorise metal oxides, dusts and sludges that enable the substitution of pig iron, and
4) the experimental testing in a furnace owned by a suitable company selected by Feralpi, for producing Fe-Si alloys starting from LF slags and Al residues,
5) the installation of a briquetting unit at Ori Martin steelmaking so as to reuse metal swarf (as containment mesh) and iron oxide (scale, rolling sludge and metal dust) creating reducing conditions into the EAF melting furnace.
Regarding the interaction with local communities, in order to partially substitute coke as input for Torbole foundry process, biogenic materials available at regional level have been selected and characterised.
The main challenge of the Brescia demo-case is to coordinate the logistics, needs and required interactions among the various value chain actors to cover the production demand without affecting the availability and quality of product and production plant productivity. To this end, Brescia demonstrator gathers several stakeholders that strongly interact in order to maximize the positive effects of an inter-sectorial approach. The main barriers to be overcome are:
– legal constraints connected to the authorisation for the new plant or to modify the already existing processes by utilising by-products and/or wastes,
– the production of alternative raw materials obtained from the treatment of by-products coming from another industry. All these activities should be completed assuring the quality, the sustainability of the technologies used and the reduction of CO2 emissions,
– contextual analysis of the territory for IS potentials (e.g. material and other resource flows, waste recovery already developed achievements, not recovered waste, residues).
So far, a deep characterisation of all the by-products and/or wastes that can be potentially used in the Brescia IS system has been accomplished and the most suitable materials have been selected.
An analysis of the most relevant KPIs related to the steelmaking industry, with a specific focus on Brescia context, was performed: indeed, a list of Industrial Symbiosis Readiness Level (ISRL) parameters was explored from several points of view (i.e. technological, economic, environmental, legal, social, etc.) and customized for the Brescia industrial scenario, in a holistic approach. The output list of relevant KPIs allows for a constant check of the progress of the IS integration in Brescia, with a quick analysis of strengths to remark and issues to be faced.
A series of laboratory and pilot plant testing were already performed and are being done to define the best composition of both briquettes (Ori Martin) and inlet materials at the reducing furnace (Feralpi). In addition, most important process parameters for separation of metallic part and sand (Torbole) and for the valorisation of organic residues containing aluminium and for energy efficiency, (Raffmetal) of have been defined. Preliminary industrial tests in the smelting furnace have been accomplished at Ori Martin site which, from one side, have confirmed the feasibility of the recycling process and, from the other side, have highlighted some constrains of the briquette management to be overcome during the project. Analysis on the environmental impact and the production process have done to confirm that suitability of briquette use.
Contemporarily, a preliminary version of the Brescia IS model has been completed. This model permits to evaluate the effect of the materials exchange in the consortium.
One of the most important bottlenecks of the IS system is the authorisation process that requires more time as foreseen and that is still in progress. Without the accomplishment of this process, there is a serious probability that some of the project activities remain as case study at laboratory level and that could not be validated at industrial scale. For example, having completed the basic engineering design of the pyrolysis plant for aluminium recovery, the construction could start only when the authorisation process is completed.
In the future, additional industrial trials with briquettes will be performed in order to better define both process parameters and industrial practices.