JPH0819487B2 - Sintering raw material charging method - Google Patents

Description

The present invention relates to a method for charging sintering raw materials in a sintering machine used in the steel industry.

[Conventional technology]

In the conventional iron and steel industry, when manufacturing a sintered ore charged into a blast furnace, a coke having an appropriate particle size is mixed with iron ore powder of about 10 mm or less, and limestone powder is mixed as necessary to form a sintering pallet. After charging, the coke on the surface layer is ignited, the coke is burned while sucking air downward, and the heat of combustion sinters the powdered ore. In this case, since the sintering progresses due to the combustion of the coke, the quality of the formation of the sintered layer, that is, the raw material filling layer is a major factor that affects the operation.

FIG. 4 is a drawing showing a raw material charging method of a conventionally used sintering machine. The sintering raw material 33 cut out from the hopper 31 by the cutting gate 32 runs from the drum feeder 34 through the sloping chute 35. The pallet 36 is loaded. In this case, the packing layer 37 formed in the pallet 36
Is detected by a layer thickness gauge 39 installed in front of the cutoff plate 38 provided on the pallet 36, and the drum feeder is set so that the layer thickness becomes a constant target value.
The supply amount of the sintering raw material 33 was adjusted by controlling the rotation speed of 34. In this way, the average layer thickness of the filling layer 37 is made constant, and the amount of pressing of the filling layer 37 by the cutoff plate 38 is made constant.

The opening of the cutting gate 32 and the sloping chute
The raw material charging control means such as the angle of 35 is readjusted only when there is a large change in the operation such as the productivity and the raw material composition.

[Problems solved by the invention]

By the way, in the above-mentioned raw material filling method, if the target layer thickness and the raw material supply amount are improper, FIG.
As shown in FIG. 3, the raw material is deposited on the pallet 36 with a constant deposition nucleus θ ′, and the deposited raw material may periodically avalanche due to the relationship between the angle of repose and the coefficient of dynamic friction. That is, as shown in FIG. 5 (B), the deposited raw material collapses and rolls to form an angle of repose .theta. To stop the avalanche phenomenon. As a result, the packed bed 37 of the raw material charged in this way forms an oblique stripe structure in which coarse particles and fine particles alternate, as shown in FIG. 6, and the packed layer 37 is packed due to the particle size and porosity of the raw material. A fine periodic change in density occurs. That is, the coarse grain portion has a high density and the fine grain portion has a low packing density. As a result, the heat history during the firing of the raw material becomes non-uniform, causing uneven burning of the raw material, which causes a reduction in sintering yield and strength. However, at present, this avalanche phenomenon of the raw material is not grasped quantitatively, and therefore, there is a problem that the raw material charging means is not properly controlled.

The present invention has been made in view of the above problems, more accurately detects the packed bed structure by grasping the packed bed at the packing density, which has been conventionally detected by the layer thickness, and prevents avalanche phenomenon and burns. Provided is a method for charging a sintering raw material with improved yield and strength.

[Means for solving problems]

The technical means of the present invention for solving the above problems are
A density meter is installed horizontally at the raw material charging position of the sintering pallet to detect the packing density of the charged sintering raw material, and the cyclic fluctuation width and fluctuation cycle of the packing density are detected based on the detected value. The avalanche phenomenon of the raw material of the packed bed is evaluated, and the raw material charging control element is controlled based on the evaluation to adjust the raw material charging amount.

[Action]

The packing density detected by the densitometer can be obtained as a fluctuation level of the density of the raw material packed bed by plotting this with time.

In general, the avalanche phenomenon of the packed bed can be prevented by reducing the cut-out amount of the raw material and reducing the angle of repose when the properties of the charged raw materials are the same, but if these are too small, the prescribed filling The layer density and layer thickness cannot be obtained, resulting in poor production efficiency. Therefore, it is preferable to charge the raw materials within the limit that the avalanche phenomenon does not occur.

When the cut-out amount of the raw material becomes excessive and the avalanche phenomenon occurs in the packed bed, the above-mentioned density fluctuates, which appears in a constant fluctuation cycle. Therefore, the avalanche phenomenon in the packed bed is evaluated from the fluctuation level, that is, the density and the fluctuation cycle, and based on this evaluation, the raw material charging control elements such as the opening of the cutting gate and the rotational speed of the drum feeder are controlled to control the raw material charging. Adjust the input amount to an appropriate value.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side sectional view of a raw material charging device of a sintering machine, and FIG. 2 is a front view thereof.

The sintering raw material 11 cut out from the hopper 1 by the cutting gate 2 is loaded into the pallet 5 which runs from the drum feeder 3 through the sloping chute 4. At the position where the raw material of the pallet 5 is loaded, three γ-ray densimeters 6 are horizontally installed near the left and right and in the middle of the pallet 5 in the width direction, and the packed bed loaded in the pallet 5 is packed. The packing density (ToN / m ³ ) of the sintering raw material forming 12 is detected. A layer thickness gauge 7 and a cutoff plate 8 are also installed downstream of the charging position.

The packing density of the sintering raw material detected by the γ-ray densitometer 6 is input to the signal processing device 9, converted into a constant electric signal, and input to the arithmetic processing device 10. In this arithmetic processing unit 10, the input electric signal of the packing density is analyzed according to a time series, and the fluctuation width and fluctuation with a fine and regular periodicity in the pallet due to the charging control factor of the packed bed 12 are analyzed. Calculate the period.

FIG. 3 is a drawing showing an example of the fluctuation level of the packed bed 12 obtained by the arithmetic processing unit 10, a graph in which the vertical axis is the charging density and the horizontal axis is time, and is plotted on this graph. From the fluctuation level curve 13 thus obtained, the fluctuation widths 14a and 14b of the density and the fluctuation cycle 15 at each charging time can be obtained. It is also possible to obtain the average value of the raw material cut-out amount from these values.

The packed bed is calculated from these fluctuation widths and fluctuation cycle results.
The structure of the packed bed 12 in 12 and the extent of the material avalanche phenomenon are evaluated, and based on this evaluation, the opening of the cut-out gate 2 which is a material charging control element, the drum feeder 3
Controls the number of rotations, the charging angle of the sloping chute 4, and the gap between the drum feeder 3 and the sloping chute 4 to suppress minute periodic packing density fluctuations caused by the avalanche phenomenon existing in each pallet. To adjust.

〔The invention's effect〕

As described above, according to the present invention, the packing density of the charging raw material is detected by the density meter without depending on the layer thickness of the packing layer, and the packing density causes a fine and periodicity in the pallet due to the charging control factor. Since the fluctuation range of packing density and the level of fluctuation cycle are obtained, the structure of the packed bed and the avalanche phenomenon can be grasped quantitatively and accurately, and therefore, appropriate raw material charging control and proper charging amount adjustment can be made. Since it is possible to prevent the avalanche phenomenon of the raw material, it is possible to obtain a uniform raw material filling structure, to prevent uneven baking, and also to stabilize the particle size distribution in the thickness direction of the packed bed and the carbon segregation. Uniform heat history is achieved, and the yield strength of the sintered ore can be improved.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a raw material charging apparatus, FIG. 2 is a front view of FIG. 1, FIG. 3 is a drawing showing an example of fluctuation level of a packed bed, and FIG. 4 is a conventional raw material charging. Schematic side cross-sectional view of the device, fifth
(A) and (B) are drawings for explaining the deposition and avalanche phenomenon of the charging raw material, and FIG. 6 is a cross-sectional view of the packing layer having a striped structure. 1 ... Hopper, 2 ... Cutting gate, 3 ... Drum feeder, 4 ... Sloping chute, 5 ... Pallet, 6 ... γ-ray density meter, 9 ... Signal processing device, 10 ... Arithmetic processing device, 11 …… Sintering material, 12 …… Filled bed

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeo Harada Inventor Takeo Harada 1 Kimitsu, Chiba Prefecture Nippon Steel Co., Ltd. Inside the Kimitsu Works (72) Inventor Tadahiro Inazumi 1-1-1, Edamitsu, Hachimanto-ku, Kitakyushu, Fukuoka 1 Nippon Steel Co., Ltd. Third Technical Research Laboratory (72) Inventor Masami Fujimoto 1-1-1, Edamitsu, Hachimanto-ku, Kitakyushu, Fukuoka Prefecture

Claims (1)

[Claims] 1. A densimeter is installed horizontally at a raw material charging position of a sintering pallet to detect the packing density of the charged sintering raw material, and the packing density changes periodically based on the detected value. A method for charging a sintering raw material, characterized in that a raw material avalanche phenomenon of a packed bed is evaluated based on a width and a fluctuation cycle, and a raw material charging control element is controlled based on the evaluation to adjust a raw material charging amount.