The Use of Tunnel Muck as Industrial Raw Material: Two Case-Studies
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ORIGINAL PAPER
The Use of Tunnel Muck as Industrial Raw Material: Two Case-Studies P. Marini • R. Bellopede
Received: 1 February 2012 / Accepted: 14 May 2012 / Published online: 6 June 2012 Springer-Verlag 2012
Abstract The re-use of rock as an industrial material requires more treatments than those foreseen for the reuse of muck as an aggregate for concrete and for road construction. The treatments always start with comminution, which has the goal of liberating the rock-forming minerals. Liberation is achieved with the appearance of grains which are composed of only one mineral. The subsequent treatment steps are based on the physical–mechanical–chemical properties of the different minerals, that is, density, magnetic susceptibility, wettability etc. Magnetic separation and flotation, the two techniques examined in this research, are the two most common techniques used in industrial mineral production plants. The mucks that were analysed are from the Omegna and Brennero tunnels, both of which are granitic rocks with different textures. From the analysis and comparison of the preliminary treatment results, it has been possible to optimise the treatment method. Petrographic, mineralogic and firing tests have been conducted to evaluate the obtained results. High-gradient magnetic separation (HGMS) on defined grain sizes appears to be suitable to obtain a product with a high feldspar–quartz content which could be used in the ceramic field.
1 Introduction The most common use of recycled waste from tunnel excavation is in the production of aggregate for roads, railways and concrete. When particular rock types are excavated, the waste generated could be more profitably used as raw material for industrial products: high-grade limestones for chemical and filler industries; limestones, marls and schists, suitable as alumina and silica source for cement production; granites and gneiss, to produce raw materials for the ceramic and glass industries; peridotites for the sand moulding, abrasive and refractory industries. It is not possible, however, to find examples of the industrial recovery of tunnel muck in the literature. This was verified during the REMUCK project (Innovative methods for the eco-compatible and sustainable recycling of muck from tunnel excavation, also considering the potential content of noxious minerals—Regione Piemonte—CIPE 2006 call-to-tender), for which this research was realised. Different techniques used to valorise the muck from two tunnels excavated in granitic rock have been studied and analysed in order to establish the optimum treatment for the requirements of the ceramic sector.
Keywords Tunnel muck Flotation Magnetic separation Granite Ceramic product 2 Materials and Methods
P. Marini (&) R. Bellopede Environment, Land and Infrastructures Department, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy e-mail: [email protected] R. Bellopede e-mail: [email protected]
Mucks from the Omegna and Brennero tunnels have been analysed: both are graniti
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