Metallurgical apparatus – Process
Patent
1995-01-24
1997-10-07
Kastler, Scott
Metallurgical apparatus
Process
266144, 266 79, 266901, C22B 700, C21B 1300
Patent
active
056739001
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the reclamation of metal from scrap.
It is becoming increasingly common to reclaim metal from scrap, for example copper from copper wire, steel from tires and aluminium from aluminium cans and containers.
Typically, the scrap is heated in a furnace to vaporise and/or partially combust the unwanted material leaving the required metal which is melted and flows to the bottom of the furnace. The vaporised and partially combusted material typically comprises acrid black fumes derived from plastic, oil, paint and grease on the metal which are then passed to an incinerator where they are burnt to convert most of the hydrocarbons to carbon dioxide and water vapour. The gas is then filtered to remove particulate material and/or scrubbed and vented to atmosphere together with some residual pollutants.
Over recent years the permissible levels of pollutants which can be released to the atmosphere has been reduced and this has necessitated the use of more fuel in the incinerators to remove a greater proportion of the hydrocarbons and more efficient filters and/or scrubbers.
EP-A-0 050 795 discloses an installation for recovering metal from scrap which installation comprises a furnace having a bath chamber and a dry hearth chamber, an exhaust duct communicating with the bath chamber and an incinerator for burning fumes from the dry hearth chamber.
In this arrangement heat from the bath chamber is transferred to the dry hearth chamber by conduction through a wall between the bath chamber and the dry hearth chamber and by conduction through the molten metal. Fumes from the dry hearth chamber are transferred to a burner firing into the bath chamber. The exhaust gasses are then vented through an exhaust duct.
Whilst this arrangement represents an improvement on the prior art insofar as the heat of combustion of the hydrocarbons is used to heat the furnace the arrangement is still relatively inefficient.
The object of at least preferred embodiments of the present invention is to reduce the volume of fuel needed for the entire reclamation process, the total volume of gas emitted to the atmosphere and the total size of the installation.
According to the present invention there is provided an installation for recovering metal from scrap which installation comprises a furnace having a bath chamber and a dry hearth chamber, an exhaust duct, and an incinerator for burning fumes from said dry hearth chamber, characterized in that said installation further comprises a source of oxygen or oxygen enriched air, and means for conveying said oxygen or oxygen enriched air to said incinerator, wherein at least a major portion of the gases leaving said incinerator is introduced into said bath chamber, wherein a minor portion of the gasses from said bath chamber is vented through said exhaust duct and at least a major portion of the balance of said gasses is passed through said dry hearth chamber and recycled to said incinerator.
A minor portion of the gases leaving the incinerator may be vented directly to atmosphere.
Preferably however, all the gases leaving said incinerator are introduced into said bath chamber.
Advantageously, said installation includes a fan for blowing fumes from said dry hearth chamber into said incinerator.
Preferably, said fan is connected to a variable speed motor to control the flow of fumes to the incinerator. Alternatively, or in addition, a control valve may be provided to control the flow of fumes to the incinerator.
If desired, said incinerator may be extended into said bath chamber and may, if desired, comprise an integral part thereof.
Preferably, the exhaust duct is provided in said bath chamber, preferably at the downstream end thereof.
In addition to satisfying the needs of the fuel (generally natural gas (methane)), oxygen should be supplied to the installation when needed to combust with the hydrocarbons in the black acrid fumes.
Advantageously, the admission of oxygen is controlled by an oxygen sensor in the furnace or in a duct which conveys hot combustion gases from the inc
REFERENCES:
patent: 3869112 (1975-03-01), Habayeb
patent: 4055334 (1977-10-01), Stephens
patent: 4060408 (1977-11-01), Kuhn
patent: 4319921 (1982-03-01), Pryor et al.
patent: 4394166 (1983-07-01), Kennedy
patent: 4402738 (1983-09-01), Akio
patent: 4548651 (1985-10-01), Ramsey
patent: 4601750 (1986-07-01), Robak et al.
Benjamin Priest Limited
Kastler Scott
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