KR20040058495A - Method for improving product yield in sintering process - Google Patents

Abstract

PURPOSE: A manufacturing method of recovery ratio improved sintered ore for steelmaking is provided to improve strength of sintered ore by supplying solid fuel such as coke breeze for sintering to surface layer part of raw material filling layer when manufacturing the sintered ore for steelmaking. CONSTITUTION: In a method for manufacturing sintered ore that is a blast furnace charging raw material for steelmaking using Dwight Lloyd sintering machine, the method is characterized in that strength of sintered ore in the surface layer part is improved by supplying coke breeze for sintering as a heat source capable of promoting formation of melt in sintering bed into a surface layer part of raw material filling layer having a depth of about 50 to 100 mm from a front part of cutoff plate(16) for controlling layer thickness of charging equipment, thereby increasing firing heat capacity and melt production amount, wherein the coke breeze is transferred from transportation vehicle, stored in hopper so that a fixed quantity of coke breeze is fed, and supplied to be dispersed into the surface layer part of the raw material filling layer by bidirectional screw feeder(10), guide plate(12) and wind force dispersion unit(14) so that the coke breeze is mixed with blended raw materials, and wherein the coke breeze is mixed with fine raw materials passing through slit bar of lower chute.

Description

METHODS FOR IMPROVING PRODUCT YIELD IN SINTERING PROCESS}

The present invention relates to a method of manufacturing steelmaking sintered ore using a die-type sintering machine, and more particularly, when manufacturing steelmaking sintered ore, solid fuel such as sintered powdered coke is supplied to the surface layer of the raw material filling layer to provide a sintered raw material layer. The present invention relates to a method for manufacturing sintered ore for ironworks, in which a recovery rate for improving the strength of sintered ore is increased by increasing the calorific heat amount and melt generation amount of the surface layer portion.

In general, DL (Dwight Lloyd) type sintering process adds powdered iron ore, secondary raw material, and powdered coke, which is a heat source, into a drum mixer, and mixes and mixes the sintered blend raw material by performing humidity control of about 6 to 7% of the weight of the raw material. Let's do it. Such a sintered blended raw material is charged to a sintering machine bogie at a certain height, surface ignited by an ignition furnace, and forced suction of air from below leads to sintering of the sintered blended raw material and to produce a sintered ore. After sintering is completed, the sintered ore is cooled by a crusher (Crusher) of the light distribution unit, cooled to a cooler, classified into a particle size of about 5 to 50 mm, which is easy for charging and reaction into the blast furnace, and then transferred to the blast furnace. At this time, less than 5mm of the spectral generated during the sintering and sintering process of the sintered ore is classified as semi-mineral and reused as sintered raw material, the amount of semi-mineral determines the sinter recovery.

The recovery rate of the sintered ore is affected by various factors such as the amount of heat supplied, the amount of binding slag, the strength and the porosity of the sintered ore, and the weak layer in the surface layer of the sintered bed significantly lowers the recovery rate of the sintered ore. This fragile layer is present in the surface layer portion from about 50 to 100 mm from the surface of the sintered raw material filling layer. The reason for the formation of the fragile layer is that in the sintering process, inevitably room temperature air is drawn from the top of the sintering raw material filling layer, so that the combustion of coke in the sintering raw material is terminated before the ore is heated to the high temperature necessary for melting the slag component. Because. Therefore, the surface layer portion of the sintered bed exhibits a weaker sintered ore property than the lower layer portion due to the lowering of the firing temperature during the firing process, the insufficient amount of melt production, and the lowering of the material filling density, and thus, the lowering of the recovery rate.

As a method for improving the strength of the surface layer portion of the sintered bed, it is possible to refine the particle size of the powdered coke used as the sintered fuel and segregate fine powder coke into the upper layer of the sintered raw material to increase the coke concentration of the upper layer portion. However, this method is difficult to control segregation loading, it is not possible to increase the concentration of fine coke only in the surface layer portion of the sintered bed, and the filling layer is excessively melted over a large area including the lower layer portion, so that it is difficult to obtain the expected effect. In addition, when the raw material is charged, the fine coke is attached to the raw material having a large particle to be charged into the lower part of the sintered bed, and it is difficult to control segregation of the coke in the raw material filling layer.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and when using a die-type sintering machine to produce a sintered ore as a raw material for steelmaking blast furnace for sintering as a heat source that can promote the formation of melt in the sintered bed Solid fuel such as powdered coke is supplied to the surface layer of raw material filling layer (depth of about 50 to 100mm) using a bidirectional screw feeder, guide plate and wind power distribution unit at the front end of the cut-off plate for post-layer control of the charging device. It is an object of the present invention to provide a method for producing sintered ore for iron making which has a recovery rate for improving the strength of sintered ore by increasing the calorific heat and the amount of melt production.

1 is a conceptual diagram showing a process according to a preferred embodiment of the present invention.

2 is a front view of the screw feeder of FIG. 1,

3 is a cross-sectional view taken along line A-A to E-E of the screw feeder of FIG.

4 and 5 are graphs showing the carbon content change according to the addition of powdered coke to the surface layer by the process of the present invention.

<Explanation of symbols of main parts in drawings>

10: screw feeder 12: guide plate

14: Wind turbine unit 16: cutoff plate

20: high carbonization zone 26: surge hopper

28: drum feeder 30: segregation guide plate

In order to achieve the above object of the present invention, there is provided a method for producing a sintered ore for manufacturing steel with improved recovery provided by a die-type sintering machine. As a heat source capable of promoting the formation of the melt, the sintered powdered coke is supplied to the surface layer of the raw material filling layer having a depth of approximately 50 to 100 mm at the front end of the charge-off cut-off plate of the charging device, thereby increasing the calorific value of the calcined heat and the amount of melt generated. It is characterized by improving the strength.

Various features and advantages of the invention, which will be described in connection with the following detailed description and the accompanying drawings, will be apparent to those skilled in the art.

As shown in the schematic diagram of the heat source addition apparatus of FIG. 1, the apparatus is mainly a pressurizing unit for conveying the crushed coke transported from a tank coke, a storage hopper for storing and quantifying the conveyed crushed coke, It consists of the bidirectional screw feeder 10 which can supply powder coke uniformly in the width direction of a coke feed pipe and a sintering machine, the guide plate 12, the wind power distribution unit 14, etc.

Meanwhile, reference numeral 26 denotes a surge hopper, 28 a drum feeder, and 30 a segregation guide plate. In addition, arrow A shows the movement direction of a trolley | bogie, B shows the flow of powdered coke, and C shows the flow of a fine raw material.

As shown in FIG. 2, the screw feeder 10, which is a powder feeder, includes a drive motor 32, a bidirectional screw 34, a powdered coke cutout 36, and a powdered coke feeder 38. In the branch coke cutout 36, five cutouts 36 are formed in a length of about 400 mm and a width of about 10 to 15 mm between the center and the end in consideration of the widthwise filling state of the powdered coke in the screw feeder. These cutouts 36 are stepped so that the angles are 15 degrees, 25 degrees, 35 degrees, 45 degrees and 90 degrees from the screw feeder center line, and the tip cutouts 36 of the bidirectional screw feeders are transferred to All the coke can be discharged so that no load is applied to the drive motor during operation.

3 shows a cross section of each part of the cutout 36, in FIG. 3, 40 denotes the cutout gate, and 42 denotes the cutout gate adjusting screw.

On the other hand, the guide plate 12 functions to transfer the powdered coke dropped from the screw feeder to the fine powder raw material drop, it is possible to adjust the angle. In addition, the wind dispersion unit 14 is provided with 30 air spray nozzles in the width direction at intervals of 150 mm, and the air injected through the nozzle functions to disperse and inject powder coke into the fine powder dropping portion.

The present invention is a bidirectional screw feeder (10), guide plate (12) and wind power at the front end of the cut-off plate (16) for post-layer control of the sintering powdered coke, which is a heat source capable of promoting melt formation in the sintered raw material layer. The dispersion unit 14 is used to feed the surface layer of the raw material filling layer having a depth of approximately 50 to 100 mm to form the high carbonization region 20 of the surface layer of the sintered raw material layer. The powdered coke supplied to the surface layer of the sintered raw material layer is surface complexed by the ignition furnace, and then the firing temperature and the high temperature holding time are increased in the surface layer to increase the calorific value and the melt production amount and improve the bond strength between the iron ore particles. In this case, the recovery rate of the weak surface layer sintered ore can be improved.

Hereinafter, the present invention will be described in more detail through Examples 1 and 2, which perform a heat source addition test in the surface layer portion of the sintered raw material layer in the sintering process.

Example 1

In the present invention, in order to quantitatively supply the sintering powder coke, which is a heat source capable of promoting melt formation during sintering, to the surface layer of the sintered raw material layer, the powder shown in FIG. A coke adder was installed. In addition, the bidirectional screw feeder 10 shown in FIG. 2 can control the amount of powdered coke added by adjusting the cutout size and the screw rotation speed.

The powdered coke used in the present invention was a powdered coke of 3 mm or less, and the coke had a composition of 86.9% fixed carbon, 2.6% volatile matter, and 10.5% ash. The amount of added coke in the sintered bed surface layer was varied from 0 to 40 kg / min under conditions of 740 mm after the sintering machine layer and a vehicle speed of 3.0 m / min (loading material amount of approximately 1000 t / hr) to investigate the quality of the surface layer sintered ore.

After the sintering was completed, the sintered ore (size 50 mm or more, about 30 kg) up to about 100 mm deep was collected from the surface by using an electric hammer drill to extract the sintered ore from the surface layer of the sintered bed. At this time, the sintered ore recovery was calculated by the following equation (1). In addition, carbon content in the surface layer was analyzed after carbonaceous material was added to the surface layer. In order to investigate the sintering temperature in the surface portion, a thermocouple (R-type) was installed at a depth of 60 mm and 100 mm from the surface of the sintered raw material layer to measure the maximum firing temperature. It was.

The carbon content change according to the addition of powdered coke to the surface layer is shown in the graphs of FIGS. 4 and 5. Figure 4 shows the carbon content according to the height of the sintered raw material layer, Figure 5 shows the carbon content along the balance width direction.

4 and 5, the carbon content of the sintered bed surface layer portion (depth 50 to 100 mm) increased from 5.1 to 6.0% after implementation at 4.4 to 4.9% of the prior art as the added coke content increased from 0 to 40 kg / min. It was. In addition, the carbon content between the central portion of the trolley and the side wall portion was also about 5.2 to 5.4% under the condition that the added coke content was 20 kg / min, indicating a relatively uniform carbon content distribution.

Table 1 shows the recovery rate and firing temperature of the surface layer sintered ore according to the surface layer added coke amount. The carbon content of the sintered bed surface layer (depth 50 to 100 mm) was increased from about 4.9% to 6.0% and the firing temperature was increased from about 1130 to 1145 ° C to about 1325 to 1338 ° C under the condition of 40 kg / min of added coke powder. Recovery was markedly improved from approximately 68.0% to 76.5%.

[Table 1] Change test results of added powdered coke in the surface layer of sintered raw material layer

division Powder Coke Addition (kg / min) % Recovery Firing temperature (℃) Carbon content Comparative example - 68.0 1130-1145 4.9 Inventive Example 1 20 72.3 1252-1295 5.4 Inventive Example 2 40 76.5 1325-1338 6.0

Example 2

In the present invention, powder coke was added at 1.0 to 1.4 t / hr to the surface layer of the sintered raw material under the operation of maintaining the total fuel consumption constant, and the test operation results are shown in Table 2. Under the same operating conditions, the recovery rate from 78.7% to 81.1%, and the productivity from 37.4% to 39.6 t / d / m2 due to the decrease of the self-reflection rate due to the improvement of the surface strength when the coke is added (0-> 1.4t / hr) Improved.

[Table 2] Test Operation Results

division Comparative example Inventive Example 1 Inventive Example 2 Addition amount (t / hr) 0 One 1.4 Productivity (t / d / m ² ) 37.4 38.2 39.6 % Recovery 78.7 80.2 81.1 Self-reflection rate (%) 21.4 19.8 18.9

From the above results, in the present invention, a bidirectional screw feeder, a guide plate, and a wind power distribution unit are formed at the front end of the cut-off plate 16 for post-layer control of the charging device, which is a sintering powder coke which is a heat source capable of promoting melt formation in the sinter bed. By supplying to the raw material filling layer surface layer portion (depth of about 50 to 100mm) by increasing the amount of calcined heat and melt production in the sintered raw material layer layer was improved the strength of the weak surface layer sintered ore could be produced to improve the recovery rate and productivity.

As described above, according to the present invention, a bidirectional screw feeder, a guide plate, and a wind power distribution unit are formed at the front end of the cut-off plate for post-layer control of a charge device, which is a source of heat that can promote melt formation in the sintered bed when the sintered ore is manufactured. It is possible to improve the recovery rate and productivity by increasing the bonding strength of the weak surface layer sintered ore by supplying to the raw material filling layer surface layer portion (depth of about 50 to 100mm) by increasing the calorific heat and melt generation amount in the surface layer portion of the raw material layer.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art may vary the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that modifications and variations can be made.

Claims (3)

In the method for producing a sintered ore which is a blast furnace charging raw material for steelmaking using a die-type sintering machine, The amount of calcined calories and melts was supplied by supplying powdered sintered coke as a heat source capable of promoting melt formation in the sintered bed to the surface layer of the raw material filled layer having a depth of approximately 50 to 100 mm from the front end of the cut-off plate 16 for post-layer control of the charging apparatus. Sintered ore production method with improved recovery, characterized in that to increase the amount of production to improve the strength of the surface layer sintered ore. 2. The bidirectional screw feeder (10) and guide plate (12) according to claim 1, wherein the powdered coke is conveyed from a transport vehicle, stored in a hopper, quantitatively dispensed from the hopper, and installed at a front end of the cutoff plate (16). And a wind power distribution device (14) is distributed and supplied to the surface layer of the raw material filling layer is mixed with the blended raw material manufacturing method of improved sintered ore. The method of claim 1, wherein the powdered coke is mixed with the finely divided raw material passing through the slit bar of the lower chute.