PROJECT DESCRIPTION
BACKGROUND
In Italy, as in all other EU Member States, aggregate materials represent the main resource taken from the environment for use in industry, principally for the construction of buildings and infrastructure. They represent more that 70% of all commercially traded quarried materials and therefore their extraction, transport and use have a considerable impact on the environment. At the same time, the industrial sector produces large amounts of waste, accounting for over 50% of all waste disposed in the environment (in Italy about 50 milion tons/year). As a consequence both quarries and landfill sites have proliferated in the last few decades. In all EU Member States the building industry is one of the principal economic sectors, attracting major investment and greatly influencing employment levels. Most buildings and infrastructure were constructed after 1940 and in the short term will need to be refurbished or replaced. This will require more stringent standards to be adhered to, both in terms of the resources used in the construction and in terms of the levels of comfort and safety requirements. Therefore the identification of new sources of materials as an alternative to natural extraction is now crucial, particularly as it is estimated that there will be considerable demand for light aggregates, which have a number of advantages over conventional materials, such as thermal stability, an easy building technology and enhanced resistance to earthquakes. In this context the LIFE LAW project aimed at demonstring the industrial feasibility of producing a commercial standard light aggregate material from wastes originating from various industrial processes.
OBJECTIVES
Using the results of other important European research projects (Brite Euram “Recbuild”, Eureka EU1176 “Granulates”) a pilot plant for the production of light aggregates was built and operated for about one year. Commercial grade light aggregates were produced and tested in pre-built concrete components. All the products obtained were tested for regulatory compliance and for many other relevant technical features. The main steps of the project were: - Preliminary environmental and economic evaluation of the process; - Identification of the critical points, introduction of new innovations and new designs for the various components; - Construction of the plant, testing, running in and optimisation of the process parameters; - Preparation of the input materials; - Operation of the plant and production of light aggregates, initially inputting 30 different waste mixtures; - Monitoring of the technical, economic and environmental parameters; - Test qualification of the 30 different batches of light aggregate produced; - Use of the aggregates for production of pre-built concrete components; - Evaluation of the potential market in Tuscany, Italy and in the EU; - Final evaluation of the economic and environmental advantages provided by the new process vs. current aggregate and light aggregate production systems and industrial waste disposal systems.
RESULTS
The LIFE LAW project demonstrated that this new innovative process could enable enhanced recovery of industrial waste, thus reducing the requirement for landfill and facilitating the production of valuable commercial light aggregate materials. The economic and environmental benefits of using this process include: - Reduced demand for industrial waste landfills; - Recovery of industrial waste from existing landfills, possibly as part of land reclamation; - Reduced demand for quarrying and therefore a reduction its negative environmental impact; - Recover of energy from organic waste components; - Overall high energy and material efficiency of the treatment plants, enabling them to operate with the lowest emission rate known for this kind of plant. The LIFE LAW project combined various innovative technologies derived from the result of other European projects. The main features that distinguish this plant from existing treatment plants are: - The possibility of tuning the process parameters on the basis of the input waste mixture available and the required characteristics of the light aggregate output; - The possibility of obtaining a wide range of light aggregate material (size ranging from 3 mm to 2 cm) - The turbo granulation system that produces a grain shape that gives enhanced performance in concrete end products; - The dual stage rotating kiln with an equi-stream hot gas flow, which enhance thermal and overall energy efficiency; - The possibility of full energy recovery due to the very high combustion temperature; - The absence of organic chlorinated contaminants in the flue gas due to the high combustion temperature and to the gas flow in the kiln. Based on an evaluation of the system, it has been estimated that a full-scale industrial plant could produce 100 t/d of light aggregate. This would meet the demand of a local market, reducing the need for long-range transport, which also has a negative environmental impact. It is estimated that this type of plant would cost around EUR 10 000 000 (including land and flue gas treatment) and would have an operating life of at least 25 years. The cost could therefore be recovered in 3 years. In Tuscany, with a network of 12 LIFE LAW plants located in industrial districts, approximately 3 million tons of light aggregate could be produced from a similar amount of special waste (from steel, chemical and tanning industries). This would provide a significant proportion of the 20 m. tons of building materials used annually in the region. Therefore LIFE LAW would reduce the quarrying requirement by at last 5 million tons per annum, would contribute significantly to the preservation of land resources and would provide net economic, social and environmental benefits to the region.
