Conditioning of chloride salt wastes from pyroprocesses through the pressureless consolidation process

Sodalite has been taken into account as a matrix for conditioning chloride salt wastes coming from pyroprocesses. The present paper illustrates the research activities finalized to demonstrate the feasibility of sodalite synthesis through the Pressureless Consolidation (PC) process, proposed by Idaho National Laboratories (INL) in USA. A homogeneous powder of nepheline, chloride salts and glass frit was put into an alumina crucible and slightly pressed with another alumina crucible of a smaller diameter, inside which a stainless steel bar had been inserted. The entire assembly was introduced in a furnace inside an Argon-atmosphere glove-box and heated at 925 C for 7 hours. The product obtained has then been characterized by means of density measurements, thermal analysis, stereomicroscopy observations, as well as FTIR and XRD. The latter correspond to the ones of sodalite reported in the spectral library. Leach tests under static conditions according to ASTM C1285-02 (reapproved 2008) have been carried out and successfully compared with those obtained by INL.