Phase Formation in the Vitrification of Savannah River Site SB4 HLW Sludge Surrogate Using Frit and Glass Forming Chemic
- PDF / 1,257,391 Bytes
- 9 Pages / 595.22 x 842 pts (A4) Page_size
- 36 Downloads / 178 Views
Phase Formation in the Vitrification of Savannah River Site SB4 HLW Sludge Surrogate Using Frit and Glass Forming Chemicals O.I. Stefanovsky,1 S.V. Stefanovsky,1 A.A. Akatov,2 J.C. Marra3 1
SIA Radon, 7th Rostovskii lane 2/14, Moscow 119121 RUSSIA Institute of Technology, Moskovskii av. 26, St-Petersburg 198013 RUSSIA 3 Savannah River National Laboratory, Building 773-42A, Savannah River Site, Aiken, SC 29808 USA 2
ABSTRACT Phase formation mechanisms associated with the vitrification of Savannah River Site (SRS) Sludge Batch 4 (SB4) high level waste surrogate with high iron and aluminum contents were studied by infrared spectroscopy (IRS), X-ray diffraction (XRD) and optical microscopy. Two mixtures at 50 wt.% SB4 waste loading were prepared as slurries with a water content of ~50 wt% using a waste surrogate and commercially available Frit 503-R4 (Li2O – 8 wt %, B2O3 – 16 wt %, SiO2 – 76 wt %) or mixture of chemicals (LiOH·H2O, H3BO3, SiO2). The mixtures were air-dried at a temperature of 115 °C and heat-treated at 500, 700, 900, 1000, 1100, 1200, and 1300 °C for 1 hr at each temperature. IR spectra and XRD patterns of the products heattreated at each temperature were recorded. In both the mixtures phase formation reactions started at low temperatures and yielded intermediate phases (sodalite, pyroxene-type, nepheline), and the reactions were mostly completed within the temperature range between 1000 and 1100 °C. The glassy materials prepared at 1200 and 1300 °C were composed of vitreous phase and magnetite/trevorite type spinel. INTRODUCTION The DOE-EM Office of Engineering and Technology is responsible for implementing EM’s international cooperative program. In the framework of this program The State Unitary Enterprise of the City of Moscow – United Ecology, Technology, Research & Development Center on RAW Management and Environmental Remediation (SIA Radon) and Savannah River National Laboratory (SRNL) are performing collaborative work on development and testing of the cold crucible inductive melter (CCIM) and its application to high level waste (HLW) vitrification technology at the US DOE sites. Specifically, the cold crucible is considered as an alternative to Joule heated ceramic melter (JHCM) used at Defense Waste Processing Facility (DWPF) [1] providing for increased waste loading in glass (higher than ~40 wt.% as in the JHCM [2]). In addition to increasing waste loading, another aspect to increase throughput is lowering temperature ranges for completion of phase formation reactions and achieving melt homogeneity faster, thus, improving the rate of melting. From this point of view, a study of phase formation mechanisms is of interest for mixtures of waste and glass formers. Understanding the phase formation mechanisms in these mixtures may allow for better control of the vitrification process. In our previous work [3] we investigated phase formation mechanism in the mixtures of Sludge Batch 2 (SB2) high-ferrous HLW and either commercially available Frit 320 or mixture of chemical simulating this frit and f
Data Loading...
