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Title: Preparation and characterization of inductively-melted synroc

Abstract

Synroc, a dense ceramic based on an assemblage of durable titanate minerals, is normally prepared by sub-solidus hot-pressing. The production of Synroc by inductive {open_quotes}skull{close_quotes} melting in a cold crucible has been developed in Russia at the end of the 1980s. The actual composition is fairly close to that of early versions of Synroc-C. A batch for Synroc production was prepared by mixing the crystalline oxides of Ca, Ba, Fe, Ni, Al, Mo, Ti and Zr as well as nitrates of Cs, Sr, Nd, Eu and Ce. The well-mixed batch was melted in the experimental plant which consisted of a high-frequency generator (1.76 MHz), process box and off-gas system. The cold crucible (88 mm in diameter and 200 mm in height) was placed within a Cu inductor. After starting the melting, the material was fed in batches. The process temperature was 1350-1400 {degrees}C. A portion of the melt was quenched by pouring onto a metal plate. Another portion of the melt was poured into a small metal container and annealed. The rest of the melt was cooled in the cold crucible and then the solidified block was removed. The material was examined by X-ray diffraction (XRD), optical microscopy (OM), scanningmore » electron microscopy (SEM) and electron-probe microanalysis (EPMA). The Synroc minerals zirconolite (CaZrTi{sub 2}O{sub 7}), perovskite (CaTiO{sub 3}), hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}) were observed in both the quenched and slowly-cooled samples. OM and SEM investigations showed the presence of some additional phases, such as alkali and alkaline-earth molybdates, Ca-Al-Ti oxide phase and hibonite. The phase compositions were evaluated in detail by SEM and EPMA, and the partitioning of key fission product elements in the different phases was evaluated and compared with those in ceramic route Synroc. There was a wide distribution in size and compositions of individual phases in the block, depending on the cooling history in the different parts of the block.« less

Authors:
 [1]; ;  [2]
  1. SIA Radon, Moscow (Russian Federation)
  2. Institute of Geology of Ore Deposits, Moscow (Russian Federation); and others
Publication Date:
OSTI Identifier:
476579
Report Number(s):
CONF-960804-Vol.3
TRN: 97:009120
Resource Type:
Conference
Resource Relation:
Conference: SPECTRUM `96: international conference on nuclear and hazardous waste management, Seattle, WA (United States), 18-23 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the international topical meeting on nuclear and hazardous waste management (SPECTRM `96): Volume 3; PB: 843 p.
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; SYNROC PROCESS; PHASE STUDIES; RADIOACTIVE WASTES; SOLIDIFICATION; MELTING; INDUCTION FURNACES

Citation Formats

Knyazev, O A, Nikonov, B S, and Omelyanenko, B I. Preparation and characterization of inductively-melted synroc. United States: N. p., 1996. Web.
Knyazev, O A, Nikonov, B S, & Omelyanenko, B I. Preparation and characterization of inductively-melted synroc. United States.
Knyazev, O A, Nikonov, B S, and Omelyanenko, B I. 1996. "Preparation and characterization of inductively-melted synroc". United States.
@article{osti_476579,
title = {Preparation and characterization of inductively-melted synroc},
author = {Knyazev, O A and Nikonov, B S and Omelyanenko, B I},
abstractNote = {Synroc, a dense ceramic based on an assemblage of durable titanate minerals, is normally prepared by sub-solidus hot-pressing. The production of Synroc by inductive {open_quotes}skull{close_quotes} melting in a cold crucible has been developed in Russia at the end of the 1980s. The actual composition is fairly close to that of early versions of Synroc-C. A batch for Synroc production was prepared by mixing the crystalline oxides of Ca, Ba, Fe, Ni, Al, Mo, Ti and Zr as well as nitrates of Cs, Sr, Nd, Eu and Ce. The well-mixed batch was melted in the experimental plant which consisted of a high-frequency generator (1.76 MHz), process box and off-gas system. The cold crucible (88 mm in diameter and 200 mm in height) was placed within a Cu inductor. After starting the melting, the material was fed in batches. The process temperature was 1350-1400 {degrees}C. A portion of the melt was quenched by pouring onto a metal plate. Another portion of the melt was poured into a small metal container and annealed. The rest of the melt was cooled in the cold crucible and then the solidified block was removed. The material was examined by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) and electron-probe microanalysis (EPMA). The Synroc minerals zirconolite (CaZrTi{sub 2}O{sub 7}), perovskite (CaTiO{sub 3}), hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}) were observed in both the quenched and slowly-cooled samples. OM and SEM investigations showed the presence of some additional phases, such as alkali and alkaline-earth molybdates, Ca-Al-Ti oxide phase and hibonite. The phase compositions were evaluated in detail by SEM and EPMA, and the partitioning of key fission product elements in the different phases was evaluated and compared with those in ceramic route Synroc. There was a wide distribution in size and compositions of individual phases in the block, depending on the cooling history in the different parts of the block.},
doi = {},
url = {https://www.osti.gov/biblio/476579}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {12}
}

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