Metallurgical apparatus – Means for treating ores or for extracting metals – By means applying heat to work – e.g. – furnace
Patent
1998-08-20
2000-08-29
Kastler, Scott
Metallurgical apparatus
Means for treating ores or for extracting metals
By means applying heat to work, e.g., furnace
266156, C22B 110
Patent
active
061104132
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a 3-stage fluidized bed fine iron ore reducing apparatus, in which a fine iron ore having a wide particle size distribution is reduced to a solid reduced iron within 3-stage fluidized bed furnaces in a stepwise manner before being put into a melting furnace. Particularly, the present invention relates to a 3-stage fluidized bed reducing apparatus in which the gas utilization rate and the reduction rate are improved.
2. Description of the Prior Art
In the conventional blast furnace, iron ore can be reduced based on the fixed bed method, because the solid particles have large sizes. However, in the case where a fine iron ore is to be reduced, if the superficial gas velocity is low as in the case of the fixed bed method, a sticking phenomenon occurs and the operation will finally be interrupted. Therefore, in this case, a fluidized bed method, in which the gas velocity is relatively high so as to make the movements of solid particles brisk, is necessarily employed.
The fluidized bed technology is widely applied to various industrial fields including the gasification of coal, boilers, oil refinery, roasting, the burning of waste materials and the like. Recently this technology has been extensively applied to the melting-reducing method which is a potential iron making technique in near future, and in which a solid iron ore is reduced by using a reducing gas.
In the conventional melting-reducing method, an iron ore is reduced in a cylindrical fluidized bed reducing furnace, and then it is transferred to a melting furnace to make pig iron. In this reducing furnace, the solid iron ore is reduced before melting it. The iron ore which is put into a reducing furnace is reduced within the melter-gasifier by means of a high temperature reducing gas obtained from the burning of fine coal or by means of a natural gas and by making the iron ore react with the reducing gas of high temperature and pressure for a certain period of time. This reducing process is classified into a fixed bed, a moving bed and a fluidized bed depending on the particle size of the iron ore and the mutual contacts between the reducing gas and the solid iron ore. In the case where a fine iron ore is reduced, a solid iron ore is put into a reducing furnace, and a reducing gas is supplied through a gas distributor. Thus the iron ore is fluidized, so that the contact area between the gas and the solid particles can be increased, thereby improving the reactivity. This fluidized bed method is known to be most efficient for the reduction of fine iron ores. So far, the iron ore reducing process which is based on the fluidized method and which is to be commercialized includes DIOS of Japan, and HISMELT and FIOR of Australia.
A fluidized bed reducing furnace is disclosed in Japanese Utility Model Application Laid-open No. Sho-58-217615.
This fluidized bed reducing furnace is illustrated in FIG. 1. Referring to this drawing, the furnace includes a cylindrical reducing furnace 111 and a cyclone 115. The cylindrical reducing furnace 111 includes: a raw iron ore inlet 112, a high temperature reducing gas inlet 113, and a reduced iron ore outlet 114. In addition, a gas distributor 116 is installed in the lower portion of the reducing furnace.
The reducing process in the fluidized bed fine iron ore reducing furnace is carried out in the following manner.
A reducing gas is supplied through the gas distributor 116 at a desired flow rate, and a fine iron ore is put through the inlet 112. Then the iron ore is reacted with the high temperature reducing gas while being agitated. Then after elapsing of some period of time, the reduced fine ore is discharged through the outlet 114.
Under this condition, the pattern of the fluidized bed is as follows. That is, the reducing gas forms gas bubbles within the reducing furnace, and as the gas bubbles pass through the particle layer of the upper portion of the reducing furnace, the gas bubbles grow bigger and bigger.
In the view of economic
REFERENCES:
patent: 4420332 (1983-12-01), Mori et al.
patent: 5762681 (1998-06-01), Lee et al.
patent: 5785733 (1998-07-01), Lee et al.
patent: 5897829 (1999-04-01), Kim et al.
Choi Nag Joon
Jung Uoo Chang
Kang Heung Won
Kim Hang Goo
Kastler Scott
Pohang Iron & Steel Co. Ltd.
Research Institute of Industrial Science & Technology
Voest-Alpine Industrieanlagenbau
LandOfFree
3-Stage fluidized bed type fine iron ore reducing apparatus havi does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with 3-Stage fluidized bed type fine iron ore reducing apparatus havi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 3-Stage fluidized bed type fine iron ore reducing apparatus havi will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1246415