JPS6028890B2 - mini pellets - Google Patents

Description

[Detailed description of the invention] The present invention relates to a mini-bellet for sintering raw materials.

As is well known, sintered ore is produced by thoroughly mixing sintering raw materials such as ore powder, coke powder, and limestone, feeding the mixture to a sintering machine, and igniting and firing the mixture in the sintering machine.
In recent years, as one of the above-mentioned sintering raw materials, gas ash generated in the blast furnace of the integrated pig steel process, collected dust of the sintering factory, dust generated in the steel blowing sickle of the converter, etc., have been used with an average particle size of 2 to 5. Unfired mini-vellets with pseudo grains on the sides are actively used. The unfired mini-vellet (hereinafter, unless otherwise specified, this unfired mini-vellet will be simply referred to as a mini-vellet) collects coke powder and Fe content in gas ash, collected dust, and converter dust, and sinters it. It is reused as a source of C and Fe○ from the ore. However, the mini-bellet,
Since it is unfired and becomes pseudo-granular, it has a high moisture content, and therefore has a problem that its strength is weak and it is easily crushed. In order to solve the above-mentioned problems with conventional mini pellets, it is necessary to increase the amount of expensive bentonite, etc., or to feed it onto the layer of sintered raw materials after mixing with a mixer, etc. It was being taught. This has led to problems such as an increase in the production cost of mini-vellets, and insufficient mixing of other sintered raw materials and mini-vellets, resulting in deterioration in the quality of the sintered ore and a decrease in the yield rate. On the other hand, the sintering raw materials include serpentine rock, silica stone, and dome for adjusting slag components in blast furnaces.

Mite, limestone, peridotite, etc. are used singly or in a mixture of several in appropriate proportions. In recent years, finely pulverized raw materials for adjusting slag components have been increasingly used in order to increase their reactivity. However, even if the raw material for adjusting the slag composition is finely pulverized, its own melting temperature is generally high, so in order to improve its melting and reactivity, the proportion of coke powder in the sintering raw material is adjusted. In addition, since it is finely pulverized, it is easy to be blown away by small wind forces and at the joints during transportation, which is causing new problems such as increased dust generation and falling ore. Ta. The present invention actively utilizes the properties of mini pellets and finely pulverized raw materials for adjusting slag components, and aims to fundamentally solve the problems of the above-mentioned conventional methods. This invention relates to a mini-bellet for sintering raw material, which is made by enclosing a finely pulverized dry raw material for adjusting slag components on the surface of the mini-vellet. Hereinafter, the present invention will be explained in detail based on Examples. Now, as mentioned above, mini pellets made by granulating gas ash, collected dust, converter dust, etc. contain coke powder as a fuel, and usually have a weight ratio of 5
Contains ~20% carbon C. Furthermore, since the granules are unfired, the moisture content generally reaches 10 to 20%. Therefore, in the present invention, a finely pulverized dry raw material for adjusting slag components (hereinafter referred to as the finely pulverized dry raw material for adjusting slag components) is pulverized on the surface of the mini pellet and has a low moisture content. (simply referred to as finely pulverized raw material), it is possible to provide a mini-belet that can exhibit various excellent functions as described below. FIG. 1 shows an embodiment of the mini-bellet 3 according to the present invention, in which the finely pulverized raw material 2 is adhered to the surface of the mini-bellet 1, for example, in a substantially uniform layer [FIG. 1a],
Or they are scattered and stuck together (Fig. 1b). In the present invention, the term "adhesion" refers to the state in which the material adheres in a substantially layered manner to the state in which it adheres in a scattered manner.

In the mini-vellet 3 of the present invention, the finely pulverized raw material 2 adhering to the surface absorbs moisture near the surface layer of the mini-vellet, so that the strength of the mini-vellet 3 is significantly improved. That is, the mini pellet 3 of the present invention has the finely pulverized raw material 2 adhered to its surface, so that the blending ratio of expensive bentonite can be increased without being destroyed during transportation or during the mixing process with other sintering raw materials. It has appropriate strength, and as a result, it has become possible to mix it with other sintering raw materials using, for example, a mixer, and it has become possible to evenly distribute it in the sintering source layer. Furthermore, as mentioned above, since mini-bellet contains a large amount of 0, it generates high heat and burns during the firing process in the sintering machine. Therefore, the finely pulverized raw material 5 stuck to the surface of the mini-bellet can effectively receive the high heat, melt quickly and reliably, and start the reaction. In particular, since the mini pellets 3 are evenly distributed among other sintered raw materials as mentioned above, the finely pulverized raw materials 2 clinging to the surface of the mini pellets 3 react evenly throughout the sintered raw material layer, resulting in the formation of sintered ores. It has become possible to significantly improve the quality of Next, an embodiment of the means for enclosing the finely pulverized raw material 2 on the surface of the mini Beretto will be described.

Figures 2 and 3 (cross-sectional view taken along the line A-A in Figure 2) are
This shows a wrapping means during the conveyance by the belt conveyor, which first supplies the mini pellets 1 to the belt conveyor 4, and then supplies a predetermined amount of the finely pulverized raw material 2 onto the mini pellet layer. Note that 5 is a feeder that supplies the finely pulverized raw material 2. The mini-bellets and the finely pulverized raw material 2 supplied thereon are sequentially mixed in the splicing section 6 of the belt conveyor 4, and during the mixing, the finely pulverized raw material 2 clings to the surface of the mini-vellets 1. Incidentally, when the number of the transfer sections 6 is small or when it is desired to further increase the mixing efficiency in the transfer section 6, it is possible to provide a plurality of shelves 7a or arrange chutes 7 as shown in FIG. 4, for example. preferable. FIG. 5 shows another embodiment of the binding means. Mini pellets 1 and finely pulverized raw materials 2 are respectively dropped in predetermined amounts into a hopper chute 9 via a feeder belt 8, and coarsely mixed during the falling. At the same time, the pulverized raw material 2 is further mixed in the splicing section 6 of the subsequent belt conveyor 4 in the same manner as in the above embodiment, and the finely pulverized raw material 2 is coated on the surface of the mini pellet 1.
and the finely pulverized raw material 2 are supplied to the mixing beletizer 10, and the mixing beletizer 10 mixes and binds the mixed beletizer 1.Although not shown in the figure, a well-known drum mixer may also be used instead. It is possible. Now,
As mentioned above, the finely pulverized raw material 2 increases the strength of the mini-vellet 3 by absorbing the moisture in the surface layer of the mini-vellet 1 that has adhered to the surface of the mini-vellet 1, and according to the experience of the present invention, It was confirmed that the above-mentioned function can be sufficiently exhibited if the product is finely pulverized to have a particle size composition that accounts for 60% or more of the grain size, and is dried to have a moisture content of 6% or less. Next, specific examples of the present invention will be described.

Example 1 The binding area is 170 53 in that D corpse binding machine
Akatsuki feed ore production was carried out at 0.5 E/day.

Table 1 shows the type and blending amount of the pulverized raw material in this example. Similarly, Table 2 shows the main components of the mini pellets, and Table 3 shows the particle size of the powdered serpentine used as the pulverized raw material. It shows the composition and moisture content. Table 1 Table 2 Table 3 In other words, in this example, a mini-vellet 3 is manufactured in which the surface of the mini-vellet is coated with grain characteristics in the vertical direction (= Eikei Cod's plan) in a weight ratio, and the mini-vellet is 3 is mixed with other sintering raw materials in a mixing machine and fed to a coagulation machine, which is different from the conventional mixer.
Compared to those supplied separately from Niveret and serpentine, the RD1 (reduced pulverization index) of the competitive ore was 2.
A 1% improvement was achieved, and the coke consumption rate was also significantly reduced by 1.1k9/ton.

Furthermore, the amount of pentonite in Mini Berets was increased to 0.6.
Despite the % reduction, the mini-bellets of the present invention had -0.5 side exponents when cut for 2 minutes with a rotor tap screen.
10-15% compared to 20-25% of conventional mini-bellets
%, and was confirmed to be difficult to destroy.
Example 2 Limestone was finely pulverized to the particle size composition shown in Table 4, and 2% of the total limestone powder was pulverized and coated on the surface of a mini-berette at a weight ratio of 1.0/1.4. A mini pellet 3 was produced, and a competitive ore was produced under the same operating conditions as in Example 1.

In this example, the RDI of the sintered ore is improved by 1% compared to the conventional mini pellet, and the coke consumption rate is also 0.5k.
We were able to reduce this by 9/tons. As detailed in Table 4 and above, by providing the mini-vellets of the present invention, it is possible to improve the quality of bran condensation to a large extent, and also to reduce the manufacturing cost of mini-vellets, and furthermore, the finely pulverized raw materials are bound to the surface of the mini-vellets. Since the material is transported in a dry state, it is also possible to prevent dust generation and port mining during transport.

As described above, the industrial effects of the present invention are extremely large.

[Brief explanation of drawings]

Each figure shows an embodiment of the present invention. FIG. 1 is a cross-sectional view a and a front view b showing a mini-vellet, and FIGS. Fig. 2 is a configuration diagram showing a conveyance situation by a belt conveyor, and Fig. 3 is a diagram showing a conveyance situation by a belt conveyor.
4 is a sectional view showing a chute with multiple shelves, FIG. 5 is a sectional view showing a conveyance structure with a hopper chute, and FIG. 6 is a sectional view of a mixing beretizer. It is a structural diagram in which - is arranged. 1: Mini pellet, 2: Finely pulverized raw material, 3: Mini pellet of the present invention, 4: Belt conveyor, 5: Feeder, 6
: Planned part, 7: Chute, 8: Feeder belt, 9:
Hot/Shoot, 10: Mixed beletizer. O diagram outside Z diagram soup 3 diagram outside 4 diagram outside diagram 5 diagram soup 6 diagram

Claims (1)

[Claims] 1 Mini pellets for sintering raw material, which are made by coating the surface of unfired carbon-containing mini pellets with finely pulverized dry raw materials for adjusting slag components.