Metallurgical apparatus – Means for melting or vaporizing metal or treating liquefied... – By stirring or mixing molten metal
Patent
1999-03-30
2000-10-24
Kastler, Scott
Metallurgical apparatus
Means for melting or vaporizing metal or treating liquefied...
By stirring or mixing molten metal
266216, 266901, F27B 304, C22B 2100
Patent
active
061362646
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a melting apparatus for melting a metal, such as aluminium, comprising a melting chamber, a burner chamber and a passage which extends between the melting chamber and the burner chamber and which has an inlet opening on the melting-chamber side and an outlet opening on the burner-chamber side for allowing molten metal to pass from the melting chamber to the burner chamber, and further comprising circulation means which are suitable for transferring molten metal to a second or pressure connection of the melting chamber from a first or suction connection of the burner chamber. Also the invention relates to a method for melting metal.
Such a melting apparatus is disclosed in U.S. Pat. No. 4,491,474.
Metal scrap to be melted is introduced into the melting chamber via a closable charging opening in a wall of the melting chamber.
In this operation, the metal scrap may first be placed on a loading incline adjoining the base of the furnace vessel in order to preheat it, after which it is pushed into the bath by metal scrap introduced later. The metal scrap can also be introduced directly into the bath.
As a consequence of the high temperatures in the melting chamber, some of the organic and combustible materials entrained with the metal scrap or adhering to it pyrolyses or, if oxygen is present, burns. Other impurities and oxides finish up in a slag layer on the molten metal, but cannot reach the burner chamber as a result of the presence of the partition.
In the burner chamber, burners are fitted to heat the molten metal. The melting capacity of the melting apparatus increases with increasing surface area of the bath in view of the transfer of heat generated by the burners to the metal. Burner offgases can be removed directly to the outside. It is also possible to pass the offgases through the melting chamber in order to preheat the metal scrap.
As the result of convection, molten metal flows within the melting chamber and within the burner chamber and between these two chambers. Molten metal which flows from the burner chamber to the melting chamber gives off heat there to the part of the bath in the melting chamber and to metal scrap still to be melted and flows back to the burner chamber.
The metal to be melted, such as aluminium, for use in such a furnace apparatus is generally metal scrap originating as residues from production processes, but it may also be metal collected from another source. The chemical composition of the metal is generally only known approximately. For the purpose of processing the metal removed from the melting apparatus further, its chemical composition should in general be between given tolerance limits. Corrections to the chemical composition, obtained after melting, of the molten metal are possible as a result of diluting the metal which forms the main constituent in the case of unduly high concentrations of alloy elements or impurities, or by adding an alloy element if its concentration in the molten metal is unduly low.
The method described above can be performed as long as molten metal of a particular composition or family of compositions has to be made and metal scrap of a particular composition or family of compositions is therefore used.
A problem with the known melting apparatus and the method of operating it arises if the chemical composition of the molten metal has to be altered, for example in the event of an alloy change. From the description of the method, it follows that the bath of molten metal in the melting apparatus functions as heat-transfer medium for transferring the heat originating from the burners or another heat source in the burner chamber to the metal scrap to be melted. During the changeover from a first chemical composition to a second chemical composition of the molten metal, it is therefore customary to empty the melting apparatus until a bath of a certain size, also referred to as residual bath, of the first composition remains. Then metal of a flushing composition or of the second composition is added to the residual bath. In
REFERENCES:
patent: 3276758 (1966-10-01), Baker
patent: 3984234 (1976-10-01), Claxton et al.
patent: 4060408 (1977-11-01), Kuhn
patent: 4128415 (1978-12-01), van Linden et al.
patent: 4491474 (1985-01-01), Ormesher
Hoogovens Aluminium N.V.
Kastler Scott
LandOfFree
Melting apparatus and method for melting metal does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Melting apparatus and method for melting metal, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Melting apparatus and method for melting metal will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1960416