A CASE STUDY ON PARTICULATE MATERIAL DERIVED FROM COMMINUTION PROCESS IN A PLANT FOR A TECHNICAL CHARACTERISATION FOR RECYCLING

The inert material processes produce a lot of fines fraction, which has to be correctly managed in relation with environmental Italian laws. Actually, the largest quantity of fines derived from comminution processes is used in quarries environmental recovery, in empties refilling, or discharged as a waste material. In this issue a fine fraction valorisation study is reported in relation with the fines reuse and recycling with an environmental, technical and economic sustainability approach. In particular a case study has been carried out with a plant for inert material production in the neighbourhood of Bologna (Italy). The process consists of many crushing and screening phases in order to produce the different commercial products. The material is washed in deslimers: washing water feeds two hydrocyclones, which separates solid phase from water. The solid phase is represented by a concentrated suspension of fine material in water which is sent to the final treatment consisting in a first sedimentation step and in a second pressing step in order to reduce the water percent of the slimes. The technical characterisation of the materials has been realised by many laboratory tests related with density analysis, size analysis, viscosity and mineralogical characteristics, heavy metals content, chemical oxygen demand (COD). Laboratory test results have shown that these materials can be reused as raw material in many industry, as ceramic or bricks production, after drying process. These results hare very interesting because it’s possible to think fine materials, which derived from comminution processes, as a resource and no more as a waste: the fine materials reutilisation can be possible in relation with technical characteristics in order to verify their applicability in many industrial processes.