Specialized metallurgical processes – compositions for use therei – Processes – Producing or treating free metal
Patent
1997-08-28
1999-11-23
Willis, Prince
Specialized metallurgical processes, compositions for use therei
Processes
Producing or treating free metal
75491, 75492, 75502, 75961, C21B 1100
Patent
active
059893095
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for injecting fine iron ore in a smelting-reducing process. More specifically, the present invention relates to a method for injecting fine iron ore, in which, in order to lower the temperature of discharge gas (reducing gas) from a melter gasifier, a fine iron ore is injected by utilizing a part of a circulating cooling gas as carrying gas.
DESCRIPTION OF THE PRIOR ART
A typical smelting-reducing method is disclosed in U.S. Pat. No. 4,978,387, in which iron ore and coal are directly used without carrying out a pre-treating process so as to produce hot metal.
In the method of U.S. Pat. No. 4,978,387, the iron ore and the ordinary coal are directly used, and the pre-treating processes such as sintering process and the coking process are omitted. Therefore, compared with other pig iron manufacturing processes such the as blast furnace process, the process and facilities are simplified. That is, as the shown in FIG. 1, the facility for carrying out the method includes: a melter gasifier 11 for converting the coal into a gas and for melting the reduced iron ore; a pre-reduction furnace 12 for indirectly reducing the iron ore by using the reducing gas generated in the melter gasifier 11; and other auxiliary facilities.
The operating temperature of the melter gasifier is 1050.degree. C. which is the condition of the complete decomposition of the tar component of the coal. The pre-reduction furnace is maintained at an operating temperature of 850.degree. C. which is the optimum condition for the indirect reduction of the iron ore.
Therefore, in order to lower the high temperature of the gas of the melter gasifier to 850.degree. C., a part of the gas which is produced in the melter gasifier is cooled down and cleaned by a venturi scrubber 17, and is subjected to a pressure stepup in a compressor 18, before being sent to an ascending tube 13. Meanwhile, the dust which is produced in the melter gasifier is separated by a cyclone 14, and passes through a dust recycling system 15. Then the dust is reinjected by a melting burner 16 into the melter gasifier in a molten condition to, thus, fall by gravity into the melter gasifier 11, thereby minimizing the losses of the fuel and the raw material.
However, the above described method has the disadvantage that only sized ore and sized coal of the optimum size (8-35 mm) can be used.
The present inventors have developed a method for alleviating the restriction of the size, and filed a patent application under Korean Patent Application No. 93-8750.
In this technique, a fine iron ore is injected into an ascending tube 13 of the melter gasifier 11 or into the recycling system 15. Then the fine iron ore together with the dust from the cyclone 14 is injected into the melter gasifier 11 by means of the melting burner 16, thereby melting and agglomerating the fine iron ore and dust. Thus the redustification is prevented, and the fine iron ore can be directly used.
However, in this technique, only the conception of injecting the fine iron ore into the melter gasifier is provided, but no descriptions are presented as to how the fine iron ore can be injected.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the conventional techniques.
Therefore it is an object of the present invention to provide a method for injecting a fine iron ore in a smelting reducing process for manufacturing a hot metal by using a fine iron ore, in which the fine iron ore is carried by utilizing a discharge gas from a melter gasifier, so that a separate gas for carrying and injecting the fine iron ore would not be required, and that the fine iron ore can be injected without any variation in the amount and composition of the process gas.
In achieving this object, the method for injecting a fine iron ore in a smelting reducing process according to the present invention includes the steps of: pre-reducing an iron ore by utilizing a discharge gas generated in a melter gasifier; smelting
REFERENCES:
patent: 4202534 (1980-05-01), Davis, Jr.
patent: 4851039 (1989-07-01), Papst et al.
patent: 4978387 (1990-12-01), Kepplinger
patent: 5338336 (1994-08-01), Greenwalt
patent: 5470375 (1995-11-01), Greenwalt
Korean Patent Application No. 93-8750 Abstract, May 21, 1993, 1 p., English-language.
Joo Sang Hoon
Kepplinger Werner L.
Lee Il Ock
Lee Sang Deok
Wallner Felix
McGuthry-Banks Tima
Pohang Iron & Steel Co. Ltd.
Research Institute of Industrial Science & Technology
Voest-Alpine Industriean-lagenbau GmbH
Willis Prince
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