Abstract:
Metal scrap such as aluminum scrap can be economically processed so as to recover the metal in the scrap by concurrently passing the scrap through a rotary kiln together with a recycled stream of hot gas. The heated scrap is separated from the gas stream at the discharge end of the kiln and is fed to a melter used to recover the metal. The separated gas stream is burned in an appropriate burner or incinerator used to provide the recycled gas stream.
Abstract:
A scrap metal feed system is described employing an endless conveyor having a surface for supporting materials thereon. The conveyor is equipped with lifters extending outwardly from the surface at periodic intervals. A first hopper feeds this conveyor and a second hopper at the inlet end of a rotary kiln receives the scrap from the conveyor. The conveyor extends horizontally beneath the bottom of the first hopper and then upwardly at an angle to the horizon less than eighty degrees and greater than fifty degrees and then terminates over the top of the second hopper. The conveyor is exposed to the interior of the first hopper as it extends upwardly at an angle to the horizontal so that material can move back along the conveyor to the first hopper as the conveyor is operated; as the material moves back to the first hopper a shearing action results which tends to break up large pieces of material and/or separate pieces of material which are adhering to each other. The material that remains on the conveyor is conveyed up the conveyor and is deposited in the second hopper. The second hopper is attached to a chute having two flapper gate valves within the interior of the chute which are coupled together such that when one flapper gate is in an open position the other is not. The coupling is achieved by rotating striker arm which sequentially abuts against a lever attached to the flapper gate valves and causes the valves to open.
Abstract:
Oil is preferably recovered from oil shale through the use of a process involving two separate heating steps. During the first of these steps the shale is heated by contact with a hot gas stream while it is agitated for a period and at a temperature which together are such that any significant further heating will cause the vaporization of pyrolysis products of the kerogen within the shale. During the second heating step the shale is further heated by contact with a hot gas stream while being agitated for a period and to a temperature which together are sufficient to produce and volatilize substantially all of the volatiles which can be obtained from or derived from the shale. After the second heating step the vaporized products and the remaining inorganic mineral matrix are separated, and the volatiles are recovered as oil.
Abstract:
In a process for decontaminating contaminated metallic scrap, an oxygen bearing hot gas stream is passed into the inlet end of a container and is discharged from an exit end of the same container. The decontaminated scrap is loaded in the container at the inlet end. Concurrently the scrap is (a) moved from the inlet end to the exit end, (b) mixed and agitated within the interior of the container, and (c) during the mixing and agitation contacted with the hot gas stream moving through the interior of the container. The contact of the scrap with the hot gas stream is under conditions essentially capable of inhibiting flaming. By virtue of the contact with the hot gas stream, heat from the hot gas stream is transferred to the scrap, which lowers the temperature of the hot gas stream while raising the temperature of the scrap. This heat transfer takes the scrap to a first temperature phase wherein contaminants such as organics are volatilized and/or cracked into volatiles which become dispensed and diluted in the gas stream. Further, water is converted into steam. The volatiles including the steam are rapidly removed from the container by virtue of their disbursement into the gas stream. Further transfer of heat to the scrap raises the scrap to a second temperature phase wherein contaminants which are not volatilable, but which are subject to oxidation below 1200.degree. F., are oxidized by oxygen in the gas stream. The scrap is maintained within the second temperature phase for a time sufficient to ensure complete oxidation and then the scrap is discharged from the container.