JPS59109771A - Dispersing plate of spare reducing furnace in melting reducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dispersion plate of a pre-reduction furnace in a smelting reduction apparatus which pre-reduces powder or granular ore containing metal oxides and then performs smelting reduction to produce molten metal. In particular, the present invention relates to a dispersion plate of a pre-reduction furnace in smelting reduction 81 for the production of 7-erochrome.

Conventional technology In recent years, the raw material ores mainly composed of various metal oxides, including iron ore, have become more powdery and granular ores rather than lumpy ores, and this proportion will continue to increase in the future. It seems that there is. The technology for manufacturing ferrochrome and other ferroalloys from powder and granular ore is usually a method using an electric furnace, but the electricity consumption is several thousand KWH/
The cost is extremely high.

As a method that does not rely on electricity, the present inventors previously proposed a smelting reduction method for producing molten metal from powder or granular ore using an apparatus in which a preliminary reduction furnace and a smelting reduction furnace are connected in series (particularly Application No. 56-63294゜Special application No. 56-68110
). This method utilizes the high-temperature exhaust gas of a smelter reduction furnace as a source of the reducing agent and heat necessary for preliminary reduction of ore containing metal oxides. The pre-reduction furnace into which this high-temperature exhaust gas is introduced is of a fluidized bed type in which the powder or granular ore is used directly in its powder or granular form without agglomerating it.

It is known that dispersion of introduced gas is important to obtain a good fluidization state in a fluidized bed. When high-temperature exhaust gas is introduced into the pre-reduction furnace as in the smelting reduction method, such dispersion of the introduced gas is particularly important. Regarding the dispersion of the introduced gas, the gas dispersion means of the preliminary reduction furnace must have the following functions.

l) It is possible to introduce high temperature reducing gas of 1000 to 1400°C from the melting reduction furnace.

2) It is difficult to be affected by the large amount of fine dust in high-temperature exhaust gas.

8) Uniform distribution of gas within the furnace is possible.

4) It is possible to prevent powdered ore and the like from flowing out of the fluidized bed when the fluidized bed is started and stopped.

Research and development of gas dispersion means that satisfy these functions is important, but as a means of dispersing the introduced gas in a conventional general fluidized bed type furnace, for example, there are many vertical There is a dispersion plate 8 having apertures therethrough.

In FIG. 1, powder or granular ore is charged onto a dispersion plate 8 in a vertical furnace l. Powder and granular ore are fluidized by the introduced gas supplied from the gas inlet 4 and passed through the openings of the dispersion plate 8, and the dispersion plate 8 that forms the fluidized bed 2 normally distributes the introduced gas uniformly into the flow M2. It is provided to disperse the In addition to the above-mentioned perforated plate type, the dispersion plate includes a sintered plate type and a bubble cap type.

However, when the conventional method is used in the preliminary reduction furnace of the melting reduction apparatus, the following problems arise. That is, in the perforated plate method, the center line of the opening of the dispersion plate 8 is parallel to the central axis of the fluidized bed 2, as shown in FIG. cannot prevent water from flowing through the openings. Furthermore, if the number of openings is reduced in order to prevent this outflow, it is difficult to uniformly disperse the gas flow within the fluidized bed, and bubbles may aggregate. Next, in the sintered plate method □, the openings are small and there is a problem of clogging due to fine dust contained in the introduced gas. In addition, the bubble cap method can prevent powder and granular ore from flowing out from the fluidized bed to the bottom of the dispersion plate during startup and shutdown, but there are problems with the material and strength that can withstand high-temperature gases of 1000°C or more. be.

OBJECT OF THE INVENTION Therefore, the object of the present invention is to solve the above-mentioned problems of the dispersion plate in the pre-reduction furnace of the conventional melting reduction apparatus, sufficiently disperse the introduced gas, and effectively form a fluidized bed.
Another object of the present invention is to provide a dispersion bed having a means for preventing powder and granular ore from flowing out of the fluidized bed when the fluidized bed is started and stopped. Particularly, it is an object of the present invention to provide a dispersion plate for a pre-reduction furnace that can be used in the production of ferrochrome using high-temperature exhaust gas.

Structure of the Invention The present invention comprises a pre-reduction furnace for pre-reducing powder and granular ore containing aged metal products in a fluidized bed, and a smelting-reduction furnace for producing molten metal by melting and reducing the pre-reduced partially reduced ore. 0 on the dispersion plate of the preliminary reduction furnace in the smelting reduction equipment
This dispersion plate has openings that introduce reducing exhaust gas generated in the smelting reduction furnace into the upper part of the dispersion plate and disperse this gas to form a fluidized bed of powder and granular ore. The perforated portion of the dispersion plate is characterized in that the angle of inclination formed between at least a portion of the center line of the perforated portion and the horizontal plane is smaller than the angle of repose of the powder or granular ore.

Detailed Description of the Structure of the Invention The preliminary reduction furnace used in the present invention can be the same as that shown in FIG. 1 described above, except for the dispersion plate 8. In FIG. 1, the preliminary reduction F is a vertical furnace L, and the side wall at the center of the hoop has a feed port 5 for feeding powder, granular ore, and flux containing metal oxides such as chromium ore. A discharge port 6 for pre-reduced ore is provided, and an exhaust lower for exhaust gas during pre-reduction is provided on the upper side wall.

At the bottom of the furnace, there is a gas inlet 4 that communicates with the inside of the furnace, and the reducing exhaust gas generated in the smelting-reduction furnace is introduced into the upper part through a dispersion plate, and the high-temperature, high-speed gas flow is used to remove powder and granular ore. A fluidized bed 2 is formed. The partially reduced ore pre-reduced in the fluidized bed 2 is transferred to the smelting reduction furnace via the discharge port 6.

The dispersion plate 8/, 3N, δ", 3' of the present invention is
- Shown in Figure 4. These distribution plates have a large number of openings that introduce exhaust gas from the smelting reduction furnace into the fluidized bed. The inclination angle α between at least a portion of the opening and the horizontal plane is made smaller than the resting angle of the powder or granular ore. If the angle of inclination α is smaller than the rest angle of repose, even if powder or granular ore accumulates on the dispersion plate, the surface will not collapse and it will remain fixed, and it will slide down from the opening of the dispersion plate and fall downward. There is no. The size of the angle α is usually about 15 to 40 degrees.

The openings of the dispersion plate 3' shown in FIG. 2(A) are provided in an oblique direction. The opening portion of the dispersion plate 8' shown in FIG. 2(B) consists of a combination of horizontal portions and vertical portions in the form of steps. Although not shown in the drawings, the apertures may have a combination of diagonal and vertical apertures. Further, as shown in FIG. 3, the apertures of the dispersion plate 8' can be formed alternately in opposite directions. These openings are formed, for example, by embedding a synthetic resin material in the openings during cold molding of the distribution plate, and removing it by melting and burning out during hot molding. These openings can be applied not only to a planar dispersion plate but also to an arch-shaped dispersion plate 87 shown in FIG.

Example Next, the present invention will be explained in detail.

Prereduction furnace fluidized bed inner diameter i, gm Type of gas distribution plate Oblique perforated plate 8' (Fig. 2 (a)
) and 81 combination (Fig. 8) Thickness: 250 cm, hole diameter: 5, angle of inclination of the porous part: α: 80 degrees, number of holes: 500 Using the above pre-reduction furnace as a test furnace, powdered chromium ore was pre-reduced under the conditions shown below. did.

l) Chromium ore: Chromium ore composition from the Philippines: ar
2o849.2% 1i'13Q 28.8% Particle size: 28~48 mesh 7.9% 48~100 mesh 86.7 inch mesh or less 5.4% 2) Pre-reduction furnace operation data Chromium ore supply amount: 180 clause/hr gas temperature
: 11300″C cox oven gas M :
l 25 Nm'/hr Pre-reduction furnace temperature: 1
By using the pre-reduction furnace equipped with the introduced gas dispersion means according to the present invention in the 020° test, it was possible to introduce high-temperature gas into the pre-reduction furnace without causing the problems that occur in conventional furnaces. Therefore, the fluidized bed could be formed satisfactorily.

Using the step-shaped perforated plate 8' (Fig. 2 (a)) under similar conditions, the preliminary reduction rate of chromium ore was as good as in the case of Fig. 2 (a).

In particular, in a perforated plate of the type shown in Figure 8, in which perforations are alternately provided in opposite directions, the direction of gas ejection is dispersed in multiple directions, resulting in a violently turbulent flow at the top of the perforated plate, which causes the gas bubbles to become coarse. The dispersion plate 8 of the prior art under similar conditions was used for the test examples 0 or more in which good results were obtained for fluidization and promotion of the reduction reaction.
In tests using
There was a spill of granular ore, and separate equipment was required to recover it.

Furthermore, in a test using the bubble cap method under similar conditions, the bubble cap could not withstand long-term operation (about one week).

In these tests, the preliminary reduction rate of chromium ore during the same time (4 hours) as in the test using the dispersion plate according to the present invention was as low as about δ8 factor.

Effects of the Invention The effects of the dispersion plate according to the present invention are summarized as follows.

l) The opening of the dispersion plate is made so that the angle of inclination between at least a part of the center line and the horizontal plane is smaller than the rest angle of the powder and granular ore, so that the powder and granular ore are not easily affected when starting and stopping the fluidized bed. It is possible to prevent granular ore from flowing out through the openings. Thereby, the furnace can be operated stably and easily.

2) In addition, since powder and granular ore do not flow out below the dispersion plate, gas can be introduced smoothly and the gas flow can be uniformly dispersed, suppressing the formation of bubbles and ensuring uniformity within the fluidized bed. The reaction is accelerated.

8) In order to improve the fluidization state of the fluidized bed, it is said that it is better to make the pressure loss of the gas in the gas distribution plate 1oLs or more than the pressure loss in the fluidized bed. Accordingly, the pressure loss necessary for gas dispersion can be obtained. (
For example, in the first embodiment described above, the gas pressure loss was 5 cm). This eliminates the problem of clogging of the pores.

4) The present invention can be easily applied to an arch-shaped dispersion plate (FIG. 4). In addition to this, as in the case of ferrochrome production,
Problems regarding the strength of materials in high-temperature fluidized beds are further resolved.

[Brief explanation of drawings]

Figure 1 is a schematic sectional view showing a distribution plate for introducing gas in a conventional pre-reduction furnace, and Figure 2 is a partially enlarged sectional view of a distribution plate showing an embodiment of the present invention. In the diagonal direction 5 (b), a stepped shape is shown. FIG. 3 is a partially enlarged plan view of a dispersion plate showing an embodiment of the present invention, showing porous portions provided alternately in opposite directions. FIG. 4 is a partial cross-section of a pre-reduction furnace showing an embodiment of the present invention. Figure υ is a diagram showing an arch-shaped dispersion plate. l... Vertical furnace of preliminary reduction furnace 2... Fluidized bed 8... Dispersion plate 4... Gas inlet 5... Raw material supply port 6゛... Preliminary reduced ore discharge port 7... Exhaust gas outlet α...Tilt angle. Fig. 1 Fig. 2゜Fig. 3 Fig. 4 Continuation of page 1 0 Inventor: Shikayasu Takada, 1 Kawasaki-cho, Chiba City, Kawasaki Steel Co., Ltd. Chiba Works 0 Inventor: Mitsuo Kakudo, 1 Kawasaki-cho, Chiba City Kawasaki Steel Corporation Chiba Works

Claims (1)

[Claims] 1 Preparation in a smelting reduction equipment consisting of a pre-reduction furnace that pre-reduces powder and granular ore containing metal oxides in a fluidized bed, and a smelting-reduction furnace that produces molten metal by melting and reducing the pre-reduced partially reduced ore. The dispersion plate of the reduction furnace has an opening that introduces the reducing exhaust gas generated in the smelting reduction furnace into the upper part of the dispersion plate and disperses this gas to form a fluidized bed of powder and granular ore. A dispersion plate of a preliminary reduction furnace in a smelting reduction apparatus, characterized in that the angle of inclination formed between at least a part of the center line of the plate and the horizontal plane is smaller than the rest angle of the powder or granular ore.