Chemical Speciation of Inorganic Compounds under Hydrothermal Conditions

Stern, Edward A. ; Fulton, John L. ; Seidler,Gerald

University of Washington, Seattle, WA

关键词: Fine Structure;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Processing;    Chromium Compounds;    Absorption;   

DOI  :  10.2172/828507
RP-ID  :  EMSP-60050--2000
RP-ID  :  FG07-97ER14818
RP-ID  :  828507

美国|英语

来源: UNT Digital Library

【 摘 要 】

This project utilizes the high-intensity x-rays available at the Advance Photon Source (APS) to study the inorganic chemistry associated with tank waste vitrification. Although the chemical conversion of waste under high-temperature conditions is an integral part of these processing technologies, there is virtually no information in the published literature about the chemical speciation of inorganic compounds under actual processing conditions. This is primarily due to the lack of techniques that are capable of making in situ measurements of aqueous systems above 300 C. The ongoing x-ray-based studies are identifying the chemical species, oxidation states and ion pairing of inorganic compounds under extreme solvent conditions. It is imperative to make in situ measurements since we have shown that the chemical speciation is strongly dependent on temperature. Several complimentary techniques are being used in this study including x-ray absorption fine structure (XAFS), diffuse anomalous x-ray scattering (DAS) and vibrational (IR & Raman) spectroscopy. Thus, the results of this work are providing information critical to the calcining and vitrification of tank wastes. The results will also have a direct bearing on specific issues such as volatility of Tc (or Re) compounds and the complex chemistry of chromium compounds.