Induction furnace and method for treating metal waste to be stored

Patent metadata

Field	Value
Publication number	US-9662693-B2
Application number	US-201414766791-A
Country	US
Kind code	B2
Filing date	Feb 17, 2014
Priority date	Feb 18, 2013
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

The melting induction furnace comprises, together with a casing ( 7 ) to which a lower sole plate ( 11 ) is added to form the central part of the structure, a removable inner crucible ( 1 ) composed of an internal layer ( 4 ) resisting heat and aggressiveness of the molten bath ( 20 ), an external layer ( 6 ) delimiting the crucible and an insulating intermediate layer ( 5 ). The crucible ( 1 ) is a disposable crucible and can be stored with its charge in an appropriate container. Heat losses are low, even when the casing ( 7 ) is cooled. Stresses due to differential thermal expansions are also very much reduced.

First claim

What is claimed is:

1. Induction furnace for melting metallic waste, with low energy consumption and high safety level, comprising a field coil ( 10 ), a circular metallic casing ( 7 ) broken down into sectors ( 8 ) separated by electrically insulating layers, surrounded by the field coil and provided with cooling fluid ducts ( 21 ), and a sole plate ( 11 ) extending under the casing, characterised in that it comprises a crucible ( 1 ) inside the casing ( 7 ) and composed of a circular wall and a bottom, the crucible being:
placed on the sole plate ( 11 ),
surrounded by the casing ( 7 ),
separated from the casing by a clearance,
continuous and uniform around its circumference and
composed of three concentric layers including an internal refractory layer ( 4 ), an intermediate layer ( 5 ) composed of compressible material and an external metallic layer ( 6 ).

2. Melting furnace according to claim 1 , characterised in that the internal layer is made from ceramic, for example based on silicon carbide.

3. Melting furnace according to claim 1 , characterised in that the intermediate layer is made from a thermally insulating material.

4. Melting furnace according to claim 1 , characterised in that the intermediate layer has a fibrous structure.

5. Melting furnace according to claim 1 , characterised in that sectors ( 8 ) have an equivalent diameter (D) less than half the penetration depth P of currents induced in the material from which the sectors are made.

6. Treatment process for metal waste to be stored, in which a furnace comprising a field coil ( 10 ), a circular metallic casing ( 7 ) broken down into sectors ( 8 ) separated by electrically insulating layers, surrounded by the field coil and provided with cooling fluid ducts ( 21 ), and a sole plate ( 11 ) extending under the casing, the furnace further comprising a crucible ( 1 ) inside the casing ( 7 ) and composed of a circular wall and a bottom, the crucible being:
placed on the sole plate ( 11 ),
surrounded by the casing ( 7 ),
separated from the casing by a clearance,
continuous and uniform around its circumference and
composed of three concentric layers including an internal refractory layer ( 4 ), an intermediate layer ( 5 ) composed of compressible material and an external metallic layer ( 6 ), the waste being poured into the crucible ( 1 ) and the field coil ( 10 ) being started to melt the waste, characterised in that waste is left until solidification in the crucible, and the crucible ( 1 ) is then removed and put into storage with the waste.

Assignees

• Commissariat L Energie Atomique Et Aux Energies Alternatives
• Areva Nc
• Commissariat Energie Atomique

Inventors

• Boen Roger
• Bonnetier Armand

Classifications

• B09B3/40 Primary

  involving thermal treatment, e.g. evaporation (processes using mineral binders involving a melting or softening step B09B3/29; involving radiation B09B3/50) · CPC title

• F27B14/061 Primary

  Induction furnaces · CPC title

• F27B2014/0843

  Lining or casing · CPC title

• F27B2014/104

  Crucible linings · CPC title

• F27B14/10

  Crucibles · CPC title