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US 5,312,525 AGranted
Method for refining molten metals and recovering metals from slags
AssigneeMassachusetts Institute of Technology
InventorsUday B. Pal, Kuo-Chih Chou
Life of this patent
Estimating the term…
Abstract
A method for electrochemical refining of an impurity-containing melt using a solid electrolyte ionic conductor to remove the impurity from the melt is provided. Also provided are an apparatus for performing the method, and a batch and a continuous method for electrochemical refining of a melt.
Claims46
A method for electrochemically refining a melt comprising the steps of:
- (1) providing a melt including an impurity and characterized by a first impurity concentration;
- (2) providing a refining gas;
- (3) exposing said melt to a refining device wherein said refining device further comprises a solid electrolyte ionic conductor, including said impurity as an ionically conductive species and characterized by a solid electrolyte electronic conductivity in electrical contact with an electrode, a refining gas inlet and a gas outlet;
- (4) introducing into said refining gas inlet said refining gas wherein said refining gas is further characterized by a second impurity concentration less than said first impurity concentration and wherein said second impurity concentration is selected to result in transport of said impurity from said melt and through said solid electrolyte ionic conductor driven by the difference between said first impurity concentration in said melt and said second impurity concentration in said refining gas and resulting in removal of said impurity from said melt to produce a refined melt characterized by a third impurity concentration, less than said first impurity concentration;
- and
- (5) short-circuiting said electrode so that transport of said impurity from said melt to said refining gas is not limited by said solid electrolyte electronic conductivity.
3 more elements
An apparatus for electrochemically refining a melt comprising:
- (1) a vessel for containing a melt wherein said melt includes an impurity and is characterized by a first impurity concentration;
- and
- (2) a refining device including:
- (2a) a refining gas inlet for introducing a refining gas characterized by a second impurity concentration lower than said first impurity concentration into said refining device;
- (2b) a solid electrolyte ionic conductor including said impurity as an ionically conductive species;
- (2c) an electrode connected to said solid electrolyte and configured to produce a short circuit to allow for direct electronic transport between said refining gas and said melt;
- and
- (2d) a gas outlet for exhausting impurity gas generated as said impurity is transported from said melt through said solid electrolyte ionic conductor driven by a difference between said first impurity concentration and said second impurity concentration and reduced to form said impurity gas to result in a refined melt characterized by a third impurity concentration less than said first impurity concentration.
5 more elements
A method for continuously electrochemically refining a melt comprising:
- (1) providing a melt refining chamber having at least one of its walls composed of a solid electrolyte ionic conductor including an impurity ionically conductive species, a melt inlet and a melt outlet and an electrode deposited on at least one of said refining chamber walls;
- (2) continuously flowing in a first direction a melt containing said impurity and characterized by a first impurity concentration into said melt inlet and into contact with said solid electrolyte ionic conductor chamber walls;
- (3) continuously flowing in a second direction, opposite to said first direction, a refining gas containing said impurity an characterized by a second impurity concentration lower than said first impurity concentration and selected to result in transport of said impurity from said melt through said solid electrolyte ionic conductor chamber walls driven by a difference between said first impurity concentration and said second impurity concentration;
- (4) exposing said electrode to said refining gas, separating said electrode from said melt by said solid electrolyte ionic conductor and short-circuiting said electrode to produce a refined melt characterized by a third impurity concentration less than said first impurity concentration;
- and
- (5) continuously removing said refined melt at said melt outlet.
3 more elements
Dependencies are inferred from the claim text.