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US 4,392,888 AGranted
Metal treatment system
AssigneeAluminum Company of America
InventorsCharles E. Eckert, Ronald E. Miller
Life of this patent
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AssigneeAluminum Company of America
InventorsCharles E. Eckert, Ronald E. Miller
Estimating the term…
Molten aluminum or other metals are purified by contacting with a fluorocarbon, such as CCl.sub.2 F.sub.2, in order to decrease the amount of impurity metal elements along with gas and inclusions therein preferably in the presence of an agitator to enhance efficiency. An oxidizer, such as oxygen, is employed to prevent the carbon in the fluorocarbon from forming carbide inclusions. Oxidizing the carbon to carbon monoxide is preferred in treating aluminum since the monoxide effectively removes the carbon from the system without oxidizing aluminum. Preferably, a fluorine acceptor is employed to temporarily combine with the fluorine in the fluorocarbon and prevent it from reacting with carbon such that the fluoride is still available to treat the molten metal. The gases employed to treat the molten metal can be passed over a bed of carbon immediately prior to introduction into the melt. The system operates with low skim generation and without providing a salt cover and is capable of substantially fume-free operation.
In a process for treating molten metal wherein said metal is contacted with halogen values from a gas containing a halocarbon the improvement comprising contacting said halocarbon with an oxidizer under conditions to oxidize carbon constituent thereof prior to introducing said halogen values into the molten metal.
In a process for treating molten metal wherein said metal is contacted with fluorine values contained in a halocarbon containing fluorine the improvement comprising contacting said halocarbon with an oxidizer under conditions to oxidize substantial portions of the carbon therein to carbon monoxide and with a fluorine acceptor to impede contacting the molten metal with CF.sub.4 and favor oxidation of carbon to CO, said fluorine acceptor yielding fluorine values for treatment of said molten metal.
In a process for treating molten metal wherein said metal is contacted with halogen values from a gas comprising a halocarbon, the improvement comprising reacting carbon in said halocarbon to produce a carbonaceous reaction product more stable in the treatment process than said halocarbon, but non-deleterious to said metal and said treatment process, prior to contacting said metal with said halogen values.
A process for treating molten aluminum with reactive fluorine values in a fluorocarbon gas comprising:
A process for treating molten aluminum with reactive fluorine values in a fluorocarbon gas comprising:
Dependencies are inferred from the claim text.