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Title: Processing of effluent salt from the direct oxide reduction process

Abstract

The production of reactive metals by Direct Oxide Reduction (DOR) process using calcium in a molten calcium salt system generates significant amount of contaminated waste as calcium oxide saturated calcium chloride salt mix with calcium oxide content of up to 15 wt. pct. Fused salt electrolysis of a simulated salt mix has been carried out to electrowin calcium, which can be recycled to the DOR reactor along with the calcium chloride salt or may be used in-situ in a combined DOR and electrowinning process. Many reactive metal oxides could thus be reduced in a one-step process without generating a significant amount of waste. The process has been optimized in terms of the calcium solubility, cell temperature, current density and the cell design to maximize the current efficiency. Based on the information available regarding the solubility of calcium in calcium chloride salt in the presence of calcium oxide, and the back reactions occurring in-situ between the electrowon calcium and other components present in the cell, e.g. carbon, oxygen, carbon dioxide and calcium oxide, it is difficult to recover elemental calcium within the system. However, a liquid cathode or a rising cathode has been used in the past to recover calcium. Themore » solubility has also been found to depend on the use of graphite as the anode material as evidenced by the presence of calcium carbonate in the final salt. The rate of recovery for metallic calcium has to be enhanced to levels that overcome the back reactions in a system where quick removal of anodic gases is achieved. Calcium has been detected by the hydrogen evolution technique and the amount of calcia has been determined by titration. A porous ceramic sheath has been used in the cell to prevent the chemical reaction of electrowon calcium to produce oxide or carbonate and to prevent the contamination of salt by the anodic carbon.« less

Authors:
;  [1];  [2]
  1. Colorado School of Mines, Golden, CO (United States). Kroll Inst. for Extractive Metallurgy
  2. EG and G Rocky Flats, Inc., Golden, CO (United States)
Publication Date:
Research Org.:
EG and G Rocky Flats, Inc., Golden, CO (United States)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
5155357
Report Number(s):
RFP-4572; CONF-9206163-1
ON: DE92013400
DOE Contract Number:  
AC34-90DP62349
Resource Type:
Conference
Resource Relation:
Conference: American Society of Mechanical Engineers (ASME) symposium, Denver, CO (United States), 8 Jun 1992
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; CALCIUM OXIDES; REDUCTION; PLUTONIUM; PRODUCTION; CALCIUM; CALCIUM CHLORIDES; CURRENT DENSITY; DISSOLUTION; ELECTROLYSIS; ELECTROLYTIC CELLS; MOLTEN SALTS; SALTS; WASTE MANAGEMENT; ACTINIDES; ALKALINE EARTH METAL COMPOUNDS; ALKALINE EARTH METALS; CALCIUM COMPOUNDS; CALCIUM HALIDES; CHALCOGENIDES; CHEMICAL REACTIONS; CHLORIDES; CHLORINE COMPOUNDS; ELEMENTS; HALIDES; HALOGEN COMPOUNDS; LYSIS; MANAGEMENT; METALS; OXIDES; OXYGEN COMPOUNDS; TRANSURANIUM ELEMENTS; 050700* - Nuclear Fuels- Fuels Production & Properties; 052001 - Nuclear Fuels- Waste Processing

Citation Formats

Mishra, B, Olson, D L, and Averill, W A. Processing of effluent salt from the direct oxide reduction process. United States: N. p., 1992. Web.
Mishra, B, Olson, D L, & Averill, W A. Processing of effluent salt from the direct oxide reduction process. United States.
Mishra, B, Olson, D L, and Averill, W A. Wed . "Processing of effluent salt from the direct oxide reduction process". United States. https://www.osti.gov/servlets/purl/5155357.
@article{osti_5155357,
title = {Processing of effluent salt from the direct oxide reduction process},
author = {Mishra, B and Olson, D L and Averill, W A},
abstractNote = {The production of reactive metals by Direct Oxide Reduction (DOR) process using calcium in a molten calcium salt system generates significant amount of contaminated waste as calcium oxide saturated calcium chloride salt mix with calcium oxide content of up to 15 wt. pct. Fused salt electrolysis of a simulated salt mix has been carried out to electrowin calcium, which can be recycled to the DOR reactor along with the calcium chloride salt or may be used in-situ in a combined DOR and electrowinning process. Many reactive metal oxides could thus be reduced in a one-step process without generating a significant amount of waste. The process has been optimized in terms of the calcium solubility, cell temperature, current density and the cell design to maximize the current efficiency. Based on the information available regarding the solubility of calcium in calcium chloride salt in the presence of calcium oxide, and the back reactions occurring in-situ between the electrowon calcium and other components present in the cell, e.g. carbon, oxygen, carbon dioxide and calcium oxide, it is difficult to recover elemental calcium within the system. However, a liquid cathode or a rising cathode has been used in the past to recover calcium. The solubility has also been found to depend on the use of graphite as the anode material as evidenced by the presence of calcium carbonate in the final salt. The rate of recovery for metallic calcium has to be enhanced to levels that overcome the back reactions in a system where quick removal of anodic gases is achieved. Calcium has been detected by the hydrogen evolution technique and the amount of calcia has been determined by titration. A porous ceramic sheath has been used in the cell to prevent the chemical reaction of electrowon calcium to produce oxide or carbonate and to prevent the contamination of salt by the anodic carbon.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {1}
}

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