Effects of slag composition and process variables on decontamination of metallic wastes by melt refining

Technical Report · Thu Jan 01 00:00:00 EST 1981

DOI:https://doi.org/10.2172/6681399· OSTI ID:6681399

Heshmatpour, B.; Copeland, G. L.

Melt refining has been suggested as an alternative for decontamination and volume reduction of low-level-contaminated metallic wastes. Knowledge of metallurgical and thermochemical aspects of the process is essential for effective treatment of various metals. Variables such as slag type and composition, melting technique, and refractory materials need to be identified for each metal or alloy. Samples of contaminated metals were melted with fluxes by resistance furnace or induction heating. The resulting ingots as well as the slags were analyzed for their nuclide contents, and the corresponding partition ratios were calculated. Compatibility of slags and refractories was also investigated, and proper refractory materials were identified. Resistance furnace melting appeared to be a better melting technique for nonferrous scrap, while induction melting was more suitable for ferrous metals. In general uranium contents of the metals, except for aluminum, could be reduced to as low as 0.01 to 0.1 ppM by melt refining. Aluminum could be decontaminated to about 1 to 2 ppM U when certain fluoride slags were used. The extent of decontamination was not very sensitive to slag type and composition. However, borosilicate and basic oxidizing slags were more effective on ferrous metals and Cu; NaNO/sub 3/-NaCl-NaOH type fluxes were desirable for Zn, Pb, and Sn; and fluoride type slags were effective for decontamination of Al. Recrystallized alumina proved to be the most compatible refractory for melt refining both ferrous and nonferrous metals, while graphite was suitable for nonferrous metal processing. In conclusion, melt refining is an effective technique for volume reduction ad decontamination of contaminated metal scrap when proper slags, melting technique, and refractories are used.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6681399
• Report Number(s): ORNL/TM-7501; TRN: 81-002884
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALUMINIUM
DECONTAMINATION
COPPER
LEAD
LEAD ALLOYS
NICKEL
RADIOACTIVE WASTE PROCESSING
MELTING
STAINLESS STEELS
STEELS
TIN
TIN ALLOYS
ZINC
SLAGS
URANIUM DIOXIDE
VOLUME
ACTINIDE COMPOUNDS
ALLOYS
CHALCOGENIDES
CHROMIUM ALLOYS
CLEANING
CORROSION RESISTANT ALLOYS
ELEMENTS
IRON ALLOYS
IRON BASE ALLOYS
MANAGEMENT
METALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PROCESSING
TRANSITION ELEMENTS
URANIUM COMPOUNDS
URANIUM OXIDES
WASTE MANAGEMENT
WASTE PROCESSING
052001* - Nuclear Fuels- Waste Processing