JPH0331412A - Fluidized bed type prereduction furnace for iron or non-ferrous ore - Google Patents

Abstract

PURPOSE:To improve the dispersing and mixing of the ore and reducing gas in a fluidized bed and to improve the uniformization and efficiency of reaction by providing plural pieces of ore supplying ports on the side wall in the lower part of a prereduction furnace and further providing plural pieces of reducing gas supplying ports below these ports. CONSTITUTION:Two pieces of the ore supplying ports 2 are provided symmetrically in the same height position of the side wall in the lower part of the prereduction furnace 1 and two pieces of the reducing gas supplying pipes 5 are provided symmetrically in the same height position below these ports. A reducing gas supplying parts 4 is formed to the bore smaller than the bore of an ore supplying part 9. The ore is dispersedly supplied via an ore supplying pipe 8, a supply rate adjusting device 7 and a supplying port 2 to the ore supplying part 9 of this constitution. The reducing gas is supplied via the reducing gas supplying pipes 5, a supply rate adjusting device 12 and a supplying port 3 to the reducing gas supplying part 4. The ore is thereby fluidized and prereduced. The prereduced ore is passed together with exhaust gases successively through a cyclone 10 by which the exhaust gases are separated. The ore is withdrawn from a product withdrawal pipe 11. The drop ore from a drop ore withdrawal port is decreased in this way, by which the yield is improved and the prereducibility of the ore is improved and stabilized.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a fluidized bed pre-reducing furnace used for pre-reducing iron or non-ferrous ore before melting and reducing it. [Prior Art] In recent years, iron or non-ferrous ore resources have tended to be of lower grade, and in order to improve the grade, low-grade ore has been beneficent and used as granule ore. As a method for producing metals or alloys from these powder ores, there is a method in which the powder ores are pre-reduced and then melted and reduced to produce metals or alloys. A rotary furnace can also be used as a device for pre-reducing fine ore, but compared to a rotary furnace, a fluidized bed furnace allows for more accurate temperature control, which prevents agglomeration of fine ore due to extreme overheating. do not have. ■Large processing capacity relative to installation area. It has the following advantages and is expected to be used more and more in the future. The above-mentioned fine grain ore generally has a maximum grain size of 3 mm and O,1
Contains powder of less than mm, and the flow rate is 2 to 1 in the fluidized bed.
For example, if 100 pre-reduced ores are to be produced per day by being fluidized with reducing gas at a rate of 1.5 oz/sec, the size of the furnace would be 2 to 6 m in inner diameter and 10 to 30 m in height, and the pre-reduction reaction would be In order to carry out the reaction uniformly and efficiently, the supplied ore particles and reducing gas must be sufficiently dispersed and mixed well with each other to react. As a fluidized bed pre-reduction furnace, for example, Tokusho 58-21
There is a furnace disclosed in Publication No. 7615, but the furnace disclosed here is a small one with an inner diameter of about 1 m, and has one ore supply port and substantially one reducing gas supply port. Depending on the type, it is difficult to sufficiently disperse and mix the ore particles and reducing gas in a fluidized bed pre-reduction furnace of the above size, and it is difficult to achieve sufficient dispersion and mixing of ore particles and reducing gas. When developing a fluidized bed pre-reduction furnace, it was desired to sufficiently disperse and mix ore particles and reducing gas.

[Problem to be solved by the invention]

The present invention aims to solve the above-mentioned needs by providing a fluidized bed pre-reduction furnace in which supplied granular ore and reducing gas can be sufficiently dispersed and mixed. [Means for Solving the Problems] In order to solve the above problems, the present invention provides a method for solving the problems described above.
Iron or iron characterized by having two or more ore supply ports for supplying ore into the furnace, and two or more reducing gas supply ports below the ore supply ports for supplying reducing gas into the furnace. The present invention provides a fluidized bed pre-reduction furnace for non-ferrous ore, and it is preferable that the inner diameter of the reducing gas supply section provided with the reducing gas supply port is smaller than the inner diameter of the ore supply section provided with the ore supply port. , [Function J] The present invention will be explained using the drawings. FIG. 1 is an explanatory longitudinal cross-sectional view of the lower part in one embodiment of the present invention. 1 is a preliminary reduction furnace, and 2.2 is two ore supply ports installed symmetrically at the same height at the bottom of the side wall of the preliminary reduction furnace 1, through which ferrous or non-ferrous powder ore is fed into the furnace. The ore supply unit 9 is supplied with the ore. 3.3 is a reducing gas supply port, which is symmetrically provided at the same height position below the ore supply port 2 on the side wall of the preliminary reduction furnace 1, and is used to supply the reducing gas sent by the reducing gas supply pipe 5. 4. 6 is an outlet for extracting fallen ore from the fluidized bed. In the present invention, if two or more reducing gas supply ports are provided below two or more ore supply ports, the number and installation positions of the reducing gas supply ports and ore supply ports are limited to the above embodiments. The more each installation is installed, and the more evenly distributed the installation positions are, the better the dispersion and mixing of the supplied ore and gas will be. It is determined as appropriate, taking into consideration the size, etc. In the present invention, since the ore is supplied into the furnace above the reducing gas and from a plurality of supply ports, it is possible to improve the dispersion and mixing of the ore and the reducing gas. In this embodiment, the inner diameter of the reducing gas supply section 4 is made smaller than the inner diameter of the ore supply section 9. By doing so, the upward flow velocity of the reducing gas at the bottom of the fluidized bed can be increased. It is possible to reduce the amount of ore falling from the fluidized bed and improve the yield of raw materials. The inner diameter of the reducing gas supply section 4 is appropriately determined in consideration of the particle size distribution of the ore used. [Example 1] A fluidized bed pre-reduction furnace of the present invention of the type shown in FIG.
The system was incorporated into a preliminary reduction device shown in a block diagram in Figure 2. The preliminary reduction furnace has an ore supply section with an inner diameter of 0.7 m, a reducing gas supply section with an inner diameter of 0.2 to 0.3 m, and a height of 7.3 m, and uses a gas having the composition (CO + 82 + N2) as the reducing gas. , the fine ore was pre-reduced at a rate of 600 kg/h. The ore is distributed and supplied to the ore supply section 9 of the preliminary reduction furnace l through the ore supply pipe 8 and the ore supply amount adjustment device 7.7,
The reducing gas is supplied through a reducing gas supply pipe 5.5 and a reducing gas supply amount adjusting device 12. ! -2, the gas is supplied to the reducing gas supply section 4 of the preliminary reduction furnace 1, rises inside the furnace 1, fluidizes the supplied ore, and performs preliminary reduction. The exhaust gas from the furnace is accompanied by pre-reduced ore. After successively passing through cyclones 10 and 10 and separating the pre-reduced ore, it is discharged from the system, and the pre-reduced ore separated by the cyclones LO and IO is extracted through the product extraction pipe 11. The fallen ore from the fluidized bed was extracted from the fallen ore extraction port 6. Through the above operations, the product yield was 90% and the preliminary reduction rate was 55%. In the same operation as above except that the fluidized bed pre-reduction furnace described above in which the inner diameter of the reducing gas supply section 4 is the same as the inner diameter of the ore supply section 9 is used, the pre-reduction rate remains unchanged and the product Since the yield was 40%, by making the inner diameter of the reducing gas supply section 4 smaller than the inner diameter of the ore supply section 9, the yield of the product could be improved. [Effects of the invention] The present invention improves the dispersion and dispersion of ore and reducing gas in a fluidized bed.
The mixing was improved, the reaction was more homogeneous, and the reaction efficiency was higher. Furthermore, by reducing the amount of ore falling, it was possible to increase the yield of raw materials and increase productivity. Furthermore, what about the present invention? ! Since it has several ore supply ports, a part of the ore discharged from the pre-reduction furnace together with the exhaust gas can be circulated to the pre-reduction furnace, thereby improving and stabilizing the pre-reduction rate.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional explanatory view showing the lower structure of an embodiment of the present invention, and FIG. 2 is a block diagram showing a system of a reduction apparatus incorporating the embodiment of the present invention shown in FIG. 1... Preliminary reduction furnace 3 - Reducing gas supply port 5 - Reducing gas supply pipe 7 - Ore supply amount adjustment device 8 - Ore supply pipe 9 - Ore supply section 10 -
... Cyclone it ... - Product extraction pipe 12 ... Reducing gas supply amount adjustment device 2 - - Ore supply port 4 ... Reducing gas supply section 6 ... Ore extraction outlet

Claims (1)

[Claims] 1. Two or more ore supply ports for supplying ore into the furnace in the lower side wall of the furnace, and two or more reducing gas ports below the ore supply ports for supplying reducing gas into the furnace. A fluidized bed pre-reduction furnace for iron or non-ferrous ore, characterized in that it is equipped with a supply port. 2. The fluidized bed pre-reduction furnace according to claim 1, wherein the inner diameter of the reducing gas supply section provided with the reducing gas supply port is smaller than the inner diameter of the ore supply section provided with the ore supply port.