JPH0328305A - Fluidized bed type pre-reduction furnace for iron or nonferrous ore - Google Patents

Abstract

PURPOSE:To improve pre-reduction ratio of ore and to execute reduction refining to obtain a metal from the powdery and granular ore with good efficiency by executing the pre-reduction to the ore in a fluidized bed type pre-reduction furnace having a specific construction before executing smelting reduction to the powdery ore. CONSTITUTION:At the time of producing a metal by executing the smelting reduction refining to the powdery and granular iron ore or nonferrous ore obtd. by ore-dressing the powdery ore of low grade in a refining furnace, this powdery and granular ore is supplied into the fluidized bed type pre-reduction furnace 1 from ore supplying holes 2 in furnace. A mixed reduction gas composed of CO, H2 and N2 is blown from lower step reduction gas supplying holes 4 arranged at lower position than the ore supplying holes 2 in the pre-reduction furnace 1 to make the powdery and granular ore in fluidized condition in the furnace, and successively, this fluidized ore is floated up with the reduction gas from upper step reduction gas supplying holes 3 and also the pre-reduction is executed with the combustion heat and is taken out from discharging hole 6 as the pre-reduction powdery and granular ore and supplied into the smelting reduction refining furnace.

Description

[Detailed Description of the Invention] [Industrial Application Field] 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. In recent years, non-ferrous ore resources have tended to become lower grade, and in order to improve the grade, low-grade ore has been beneficent and used as grain ore. As a method for producing metals or alloys from these grain ores, there is a method in which the grain 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 granule ore, but compared to a rotary furnace, a fluidized bed furnace has more accurate temperature control, which prevents agglomeration of granule 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 particle size of 3 mm and an O. l
Contains powder of less than mm, and the flow rate in the fluidized bed is 2 to 1
om/sec of reducing gas, and if pre-reduced ore is to be produced in one day, the size of the furnace will be 2 to 6 m in inner diameter and 10 to 30 m in height, ensuring that the pre-reduced reaction is uniform. In order to carry out the reaction efficiently and efficiently, it is necessary that the supplied ore particles and the reducing gas are sufficiently dispersed and mixed well with each other for the reaction to occur.

As a fluidized bed pre-reduction furnace, for example, JP-A-58-21
There is a method disclosed in Publication No. 7615, but the one disclosed here has a small furnace 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 1] The present invention seeks to solve the above-mentioned needs by providing a fluidized bed pre-reduction furnace in which supplied powder 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 two or more upper reducing gas supply ports and two or more lower reducing gas supply ports in the lower part of the furnace for supplying reducing gas into the furnace. , to provide a fluidized bed pre-reduction furnace for iron or non-ferrous ore, characterized in that two or more ore supply ports for supplying ore into the furnace are provided between the upper and lower reducing gas supply ports. It is.

[Operation 1] The present invention will be explained using the drawings. FIG. 1 is an explanatory longitudinal cross-sectional view showing the lower structure in one embodiment of the present invention.

i is the preliminary reduction furnace, 3.3 is the upper reducing gas supply port, 4.4
are the lower reducing gas supply ports, two of which are provided each, and the -L side of the lower gas supply ports 4.4 has a large number of small holes.
Reducing gas is supplied into the furnace from these gas supply ports, and 2
．． Reference numeral 2 denotes two ore supply ports provided between the upper and lower reducing gas supply ports, through which ferrous or non-ferrous granular ore is supplied into the furnace. 6 is an outlet for extracting fallen ore from the fluidized bed.

In the preliminary reduction furnace of the present invention, the ore supplied into the furnace from the ore supply [ ] 2.2 is first brought into a fluid state with the reducing gas supplied from the lower stage reducing gas supply port 4.4, and then the ore is brought into a fluidized state by the reducing gas supplied from the lower stage reducing gas supply port 4.4. The ore can be floated smoothly with the reducing gas supplied from the gas supply port 3.3, and moreover, two or more ore supply ports, upper stage and lower stage reducing gas supply ports are each provided, so Separation and mixing of ore and reducing gas is completed. In the present invention, if they are provided between two or more ore supply ports or two or more upper and lower reducing gas supply ports, the number, installation position, and structure of the reducing gas supply ports and ore supply ports are is not limited to the above example, and the more the number of each installation is, the more evenly distributed the installation positions, the better the distribution and distribution of the supplied ore and gas.
In order to achieve good mixing, the number and location of each installation should be determined appropriately, taking into account the size of the furnace, etc. [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 inner diameter of 0. 7 m long and 7.3 m high, the ore was pre-reduced at a rate of 600 kg/h using a gas with the composition (CO+82+N2) as the reducing gas. The ore is distributed and supplied to the preliminary reduction furnace 1 through the ore supply pipe 8 and the ore supply amount adjustment device 7.7, and the reducing gas is supplied to the upper reducing gas supply port and the lower reducing gas supply port through the reducing gas supply pipe 5. The ore is supplied to the pre-reducing furnace 1 through the furnace 1, rises inside the furnace 1, fluidizes the supplied ore, and
sm yuan.

12 is a reducing gas pressure adjustment device that adjusts the pressure of the reducing gas between the upper reducing gas supply port and the lower reducing gas supply port.

The exhaust gas from the furnace I, together with the pre-reduced ore, is passed through the cyclone 9. After successively passing through the IO and separating the pre-reduced ore, the pre-reduced ore is discharged from the system and separated in cyclone 9.10.
The reduced ore is extracted through a 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 above apparatus, as a comparative example, the preliminary reduction rate remained unchanged in the same operation as above except that the above fluidized bed pre-reduction furnace was used with the lower reducing gas supply port 4 set to 1111. Since the product yield was 40%, it was possible to improve the product yield by providing a plurality of reducing gas supply ports in two upper and lower stages.

[Efficacy of the invention 1 The present invention enables 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, since the present invention has a plurality of ore supply ports, a part of the ore discharged from the preliminary reduction furnace together with the exhaust gas can be circulated to the preliminary reduction furnace, thereby improving and stabilizing the preliminary reduction rate. can.

[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...1,000 m reduction furnace 2...ore supply port 3...upper reducing gas supply port 4...lower reducing gas supply port 5...reducing gas supply pipe 6...Ichiraku ore extraction outlet 7 ...Ore supply amount adjustment device 8-・One ore supply pipe 9.10 ...Cyclone l1 ...Product extraction pipe I2 ...Reducing gas pressure adjustment device

Claims (1)

[Claims] 1. At the bottom of the furnace, 2 each supply reducing gas into the furnace.
An iron characterized by having at least two upper reducing gas supply ports, a lower reducing gas supply port, and two or more ore supply ports intermediate the upper and lower reducing gas supply ports for supplying ore into the furnace. Or a fluidized bed pre-reduction furnace for non-ferrous ore.