Specialized metallurgical processes – compositions for use therei – Processes – Process control responsive to sensed condition
Patent
1995-07-17
1997-09-23
Andrews, Melvyn
Specialized metallurgical processes, compositions for use therei
Processes
Process control responsive to sensed condition
75386, 75436, 75469, 75491, 266 87, 266181, C21B 724
Patent
active
056699557
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to a process for producing pig iron from metal ores, in which the metal ores and optionally added additions travel from the top downwards through a reduction unit through which a hot reduction gas containing carbon monoxide and hydrogen flows from the bottom upwards, and the reduction product is drawn off at the bottom end of the reduction unit and is fed to a unit serving for further treatment thereof, the reduction gas being generated in a gas generator by partial oxidation of carbon carriers or by cracking of natural gas or petroleum, and to an apparatus for the thermal and/or chemical treatment of a readily disintegrating material or for producing pig iron by means of said process, with a first unit for generating a hot gas, in particular a reduction gas, and a second unit for holding the material to be treated thermally and/or chemically, having at least one material inlet arranged in the top section of the second unit and at least one discharge appliance arranged at the bottom end of the second unit for drawing off the material treated thermally and/or chemically, and having at least one inlet for the hot gas arranged in the bottom zone of the second unit.
It has been known for a long time that iron ore in the form of pellets, chunks or lump ore can be converted in a blast-furnace into sponge iron by allowing a hot reduction gas to flow from the bottom upwards through a descending bed of ore particles.
Technical difficulties and economical problems are posed, on the other hand, by the reduction of the ore if it is present in fine form. Although it has been proposed to reduce fine ore in a fluidized-bed reduction reactor to produce sponge iron, the fine ore particles being suspended in a hot reduction gas. However, it is equally known that, upon attaining it begin to agglomerate in such a process, and that, as the degree of reduction increases, large clusters are formed which block the gas paths through the ore and usually result in the failure of this procedure.
A further drawback of these known processes is the high loss of material due to dust discharge, and a high energy expenditure. The dust is produced mainly in the bottom zone of the reduction unit and may be enriched with additional dust originating from the gas generator. The reduction gas carries this dust along.
The product of these direct reduction installations is sponge iron in the form of lumps or compacted into briquettes, which is smelted in electric furnaces or other units.
A more recent process, implemented industrially and described in German Patent Specification 2843303, like the conventional blast-furnace route requires as its starting material screened lump ores and fine ore processed into pellets or sinter. The latter, however, requires additional investment and a higher energy expenditure. The process consists in the sponge iron being discharged hot from the shaft furnace and being smelted in a smelting gasifier, using coal as an energy source and oxygen as an oxidant. The gas generated in the smelting gasifier during the smelting process is used, after dedusting in a cyclone end part-stream cooling in a scrubber, as the reduction gas for the reduction shaft. The hot dust precipitated in the cyclone is recycled into the smelting gasifier and is gasified with the aid of an oxygen burner. Recycling and gasifying the hot dust, which has a temperature of approximately 800.degree. C., is not without its problems, and any disruption in this system leads to problems in the reduction shaft, as it can accommodate only limited amounts of dust, although it is operated only with lumpy iron oxides.
The blast-furnace route requires coke as an energy source, whose production constitutes that step in the pig iron production process, which is the most heavily polluting and results in an enormous increase in production costs. In addition, a shortage of coking coal of acceptable quality is apparent even today. In contrast to the blast-furnace, in the case of the abovementioned, more recent process, known under
REFERENCES:
patent: 3512766 (1970-05-01), Oberndorfer
patent: 4670049 (1987-06-01), Kelmar
Vuletic Bogdan
Vuletic Bojan
Vuletic Vladan
LandOfFree
Process for producing pig iron from iron ores, and applicance fo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing pig iron from iron ores, and applicance fo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing pig iron from iron ores, and applicance fo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1937531