Process for removing volatiles from metal

A process for delacquering scrap aluminum beverage cans comprising the steps of:

• (a) reducing said aluminum cans to small pieces less than 6 inches in length;
• (b) conveying said small pieces of aluminum into a furnace and heating to a temperature of between 900.degree. and 1100.degree. F. to vaporize volatiles contained thereon without oxidizing said aluminum, said vaporizing producing fumes containing unburned hydrocarbons;
• (c) burning said fumes containing said unburned hydrocarbons to produce hot gas having a temperature of between 1200.degree. and 1500.degree. F. and mixing said hot gas with a cooler gas to obtain a mixed gas stream having a temperature of between 900.degree. and 1050.degree. F.;
• (d) recirculating said mixed gas stream to said furnace and through said perforated surface of said conveyor at a sufficient velocity to heat and fluff incoming aluminum;
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• (e) vibrating said aluminum to maximize contact between the surfaces of said aluminum and said recirculating mixed gas stream to vaporize substantially all volatiles contained thereon.

A process for removing organic volatiles from the surface of aluminum comprising the steps of:

• (a) reducing said aluminum to small pieces less than eight inches in length;
• (b) conveying said small pieces of aluminum to a furnace and hating to vaporize said volatiles, said vaporizing producing fumes containing unburned hydrocarbons;
• (c) burning said fumes containing said unburned hydrocarbons in an incinerator at a temperature of between 1000.degree. and 1500.degree. F. to product a hot gas;
• (d) mixing said hot gas with a cooler gas to form a recirculating gas having a temperature of between 900.degree. and 1050.degree. F.;
• (e) recirculating said gas through said small pieces of aluminum to heat and fluff the pieces;
• (f) routing a portion of said recirculating gas to an upstream portion of said furnace and introducing sufficient oxygen to heat incoming aluminum pieces and vaporize volatiles contained on the surface thereof and routing the remaining portion of said recirculating gas to a downstream portion of said furnace where said gas contacts said aluminum leaving said upstream portion and pyrolyzes said aluminum to remove any carbon present on the surface thereof;
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• (g) vibrating said aluminum while within said furnace to maximize contact between the surface of said aluminum and said recirculating gas to vaporize substantially all volatiles contained thereon.

A process for removing volatilizable contaminants from the surface of metal, comprising the steps of:

• (a) shredding said metal into small pieces;
• (b) routing said small pieces into a furnace and removing metal free of volatile surface contaminants from said furnace after a predetermined period of time;
• (c) controlling the temperature and oxygen content within said furnace to facilitate vaporization of said volatiles without oxidizing said metal, said vapors containing unburned hydrocarbons;
• (d) burning said vapors containing unburned hydrocarbons to produce a hot gas;
• (e) recirculating said hot gas throughout said furnace and into contact with said metal, said gas having a velocity of at least 10,000 feet per minute, said recirculated gas fluidizing said metal and causing outward expansion thereof;
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• (f) vibrating said metal to maximize contact between the surface of said metal and said recirculating gas to facilitate vaporization of substantially all volatiles contained thereon.

A process for removing volatilizable contaminants from the surface of metal, comprising the steps of:

• (a) shredding said metal into small pieces;
• (b) conveying said small pieces of metal into a furnace and removing metal free of volatile surface contaminants from said furnace after a predetermined period of time;
• (c) controlling the temperature of said furnace between about 800.degree. and 1200.degree. F. and controlling the oxygen content of said furnace between about 8 and 12% to facilitate vaporization of said volatiles without oxidizing said metal, said vapors containing unburned hydrocarbons;
• (d) burning said vapors containing unburned hydrocarbons to produce a hot gas;
• (e) recirculating said hot gas throughout said furnace and into contact with said metal, said gas having a velocity of between about 10,000 and 60,000 feet per minutes, said recirculated gas fluidizing said metal and causing outward expansion thereof;
• and
• (f) vibrating said small pieces of metal to maximize contact between the surface of said metal and said recirculating gas to facilitate vaporization of substantially all volatiles contained thereon.