Specialized metallurgical processes – compositions for use therei – Processes – Producing or treating free metal
Patent
1997-05-30
1999-12-07
Andrews, Melvyn
Specialized metallurgical processes, compositions for use therei
Processes
Producing or treating free metal
266144, 266166, C21B 1314
Patent
active
059976098
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for producing sponge iron from particulate iron-oxide-containing material, wherein the iron-oxide-containing material in a reduction zone is reduced to sponge iron by means of reducing gas and the gas forming during reduction is withdrawn as top gas, as well as to a plant for carrying out the process.
With a process of this type known, for instance, from EP-B-0 010 627, from DE-C-40 37 977 and from AT-B-376,241, the sponge iron formed by the direct reduction is smelted in a meltdown gasifying zone under supply of lumpy carbon carriers and oxygen-containing gas, wherein a fluidized bed is formed in the meltdown gasifying zone from the lumpy carbon carriers and by blowing in oxygen-containing gas, in which fluidized bed the sponge iron particles top-charged into the meltdown gasifiying zone are braked and melted. In doing so, a reducing gas containing CO and H.sub.2 is produced, which is injected into the reduction zone and reacted there.
During this reaction, a large amount of top gas incurs, which still has a considerable content of carbon monoxide and hydrogen. If utilization of this top gas is feasible in an economic manner, production costs for sponge iron and pig iron melted therefrom or steel pre-products produced therefrom will be very low.
It is known (DE-C-40 37 977) to supply top gas escaping from the reduction zone to a further reduction zone for reducing additional iron-oxide-containing material after having been subjected to purification. The treatment of top gas, in general, is effected by initially purifying the same from solids particles in a scrubber while being strongly cooled. After this, the CO.sub.2 contained in the top gas is eliminated, because this would impede further utilization of the top gas as a reducing gas. Various methods have been known for the purification of top gas from CO.sub.2, for instance, the pressure-swing process or chemical CO.sub.2 -scrubbing.
According to DE-C-40 37 977, it has been possible to utilize the energy chemically bound in the top gas to a major extent Yet, this involves the problem of CO.sub.2 -containing offgas incurring in the purification of top gas, which offgas has to be disposed of in an environmentally safe manner.
This offgas, i.a., contains CO, H.sub.2, CH.sub.4 as well as H.sub.2 S and, as a result, cannot be released to the environment in such state for reasons of environmental protection. For this reason, it is suited for further processing also to a limited degree only. Consequently, the sulfur compounds usually are eliminated from the offgas. So far, such desulfurization has been carried out by means of various methods, such as, for instance, by what is called "Stretford scrubbing" or by catalytic oxidation on activated carbon, etc. From DE-B-37 16 511 it is known to remove H.sub.2 S from CO.sub.2 -containing offgas in a desulfuization reactor by aid of sponge iron. All of these methods are expensive, requiring additional materials, such as activated carbon or absorbants, which, i.a., must be stored and disposed of separately.
It is internally known to bleed off CO.sub.2 -containing offgas. However, such bleeding off involves the provision of combustible supporting gas as ignition and carburizing gas, since the calorific value of the CO.sub.2 -containing offgas is only low.
From EP-A-0 571 358 it is known to subject top gas incurring in the direct reduction of fine ore by aid of a reducing gas formed of reformed natural gas to CO.sub.2 -scrubbing and to admix the thus purified top gas to fresh reducing gas obtained from natural gas by reforming and to introduce this gas mixture into the reduction zone. Again, this involves the problem of disposing of the CO.sub.2 -containing offgas incurring in the purification of the top gas, although this offgas, due to the production of the reducing gas from reformed natural gas, has a lower H.sub.2 S-content than the offgas incurring in the top-gas purification of reducing gas obtained from lumpy carbon carriers.
The invention aims at avoiding these disadvantages an
REFERENCES:
patent: 1800856 (1931-04-01), Bradley
patent: 3653874 (1972-04-01), Schulte
patent: 5238487 (1993-08-01), Hauk et al.
patent: 5676732 (1997-10-01), Viramontes-Brown et al.
Patent Abstracts of Japan, vol. 2, No. 100 (C-020), Aug. 18, 1978 & JP-A-53 062718, Jun. 5, 1978.
Patent Abstracts of Japan, vol. 8, No. 222 (C-246), Oct. 9, 1984 & JP-A-59-107009, Jun. 21, 1984.
Patent Abstracts of Japan, vol. 10, No. 280 (C-374), Sep. 24, 1986 & JP-A-61-009613, May 17, 1986.
Patent Abstracts of Japan, vol. 940, No. 010 & JP-A-06 287001, Oct. 11, 1994.
Diehl Jorg
Rosenfellner Gerald
Andrews Melvyn
Voest-Alpine Industriean-lagenbau GmbH
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