JPS6028891B2 - Pre-treatment method for sintering raw materials - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for pre-treating sintering raw materials.

As is well known, in order to prepare Akatsuki ore, sintering sources such as ore powder, coke powder, and limestone powder are thoroughly mixed using a mixing machine, etc., and then fed to a sintering machine. This is done by igniting and firing.

As one of the competitive raw materials, for example, gas ash generated in a blast furnace in the integrated pig steel process, collected dust in a sintering factory, dust generated in a steel blowing sickle in a converter, etc., are mixed with an average particle size of 2 to 5 feet. It is also well known that unfired mini pellets, which have been made into pseudo-granules, are used, and serpentinite is used to adjust the basicity and slag content of morning concretion, and to adjust the Mgo content in blast furnace slag. By the way, the above-mentioned mistress sex beretsu (hereinafter, unless otherwise specified,
This unburned pellet (simply referred to as mini pellet) is used to recover coke breeze and Fe content from gas ash, collected dust, and converter dust, and reuse it as a source of C and Fe0 for calcined ore. . However, since this mini-pallet is unfired and turned into pseudo-granules, it has a high moisture content, and also has a problem that its strength is weak and it is easily crushed. Therefore, in order to solve the above-mentioned problems with conventional mini-berets, it is necessary to increase the amount of expensive bentonite, etc., or to feed the mixture mixed in the mixer onto other sintering materials during transportation. It was common. For this reason, in the former case, the manufacturing cost of mini-pallets increases, and in the rear car, other competitive raw materials and mini-pellets are not sufficiently mixed, resulting in problems such as deterioration of the quality of sintered ore and a decrease in yield unit. had. On the other hand, the serpentinite is
For the purpose of increasing the reactivity, in recent years, fine powder serpentinite containing 60% or more of grains with a particle size of 1 or less (hereinafter referred to as "grain serpentinite") has come to be widely used. However, even in the form of fine powder, the melting temperature of serpentine itself is high, so in the past, in order to increase melting and reactivity, it was necessary to increase the blending ratio of granular coke in the raw material for agglomeration. Powdered serpentinite is easily blown away by small wind forces and the joints of belt conveyors, and has started to pose new problems such as increased dust generation and falling ore. The present invention actively utilizes the physical properties of mini-vellets and serpentinite to fundamentally solve the problems of the conventional art,
The gist is that a predetermined amount of powdered serpentinite is supplied onto the layer during transportation, and after rough mixing, the reactivity of the serpentine is increased by mixing it with other sintering raw materials other than the mini pallet and serpentine. The present invention relates to a method for pre-processing sintering raw materials, which is characterized by producing sintered ore with excellent properties. The present invention will be described in detail below based on Examples. FIG. 1 shows a plan layout in which the present invention is implemented in a well-known general sintering factory. In the figure, 1 is a granulator for manufacturing mini pellets, 2 is a storage hopper for differential serpentinite, and 3 is a primary mixer. 4a and 4b are mini-bellets such as fine ore, coke powder, and return ore, and other sintering raw materials other than serpentine (hereinafter, other sintering raw materials other than mini-bellets and serpentine are simply referred to as other sintering raw materials). The ore storage hopper, 5a, stores all sintering raw materials including mini pellets and serpentine (referred to as sintering raw materials).
~5f is a belt conveyor that conveys each of the raw materials; 6a;
6b shows a belt conveyor that conveys high-temperature return ore.

In the present invention, the mini pellets 7 manufactured by the granulator 1 are supplied to the belt conveyor 5a and transported by the conveyor. The powdered serpentinite 8 is cut out from the storage hopper 2 and placed in the second
As shown in the figure, a predetermined amount is supplied onto the layer of mini pellets 7 that are being conveyed using a belt conveyor technique. Since the mini-vellet 7 contains a large amount of water as described above, the serpentinite supplied onto the mini-vellet layer is adsorbed to the mini-vellet 7, and its scattering is prevented. The mini pellets 7 and the serpentines 8 are conveyed sequentially on the belt conveyor & phantom, but during this conveyance, for example, during the conveyor belt 5c to 5d, and when being fed from the belt conveyor 5d to the primary mixer 3, etc. During this rough mixing,
As shown in FIG. 3, the powdered serpentinite 8 adheres to the surface of the mini-vellet 7. Due to the adhesion of the powdered serpentinite 8, water in the mini-vellet 7 is absorbed by the powdered serpentinite 8, and therefore the strength of the mini-vellet 7 is significantly improved. In addition, since the powdery serpentinite 8 adheres to the mini-beret 7 in an adsorbed manner, no dust is generated during the above-mentioned transfer and charging, and the falling of the ore can be prevented. The means for coarsely mixing the mini-vellets 7 and the powdered serpentinite 8 is not limited to the above-mentioned embodiment. However, it is possible to install a well-known drum mixer, or to install a chute 20 with multiple shelves 21 as shown in FIG. Bye.

In addition, the amount of serpentinite 8 supplied onto the mini-bellet layer is:
If the amount is too large relative to the amount of the mini-vellets 7, the effect of preventing dust generation will be reduced, and if it is too small, the effect of improving the strength of the mini-vellets will be undesirable. In the experience of the present inventors, good results were obtained by setting the ratio of powdered serpentine to mini-vellet in the range of 0.3/1 to 1/1 (weight ratio). Now, the mini pellets 7 and powdered serpentinite 8 that have been mixed together are fed to the primary mixer 3, where they are cut out from the storage hoppers 4a, 4b, and transferred to the belt conveyors 5e, 5f, The sintered raw materials are mixed together with other sintering raw materials fed through conveyors 6a and 6b.

Therefore, in the primary mixer 3, the mini pellets 7 are evenly mixed into the other sintering raw materials, and the mini pellets 7 are evenly mixed into the other sintering raw materials.
The powdery serpentinite 8 attached to the surface of the mini-vellet adheres more uniformly and firmly to the surface of the mini-vellet, promoting pseudo-graining of the mini-vellet 7, thereby causing the powdery serpentinite 8 to also be mixed with other sintering raw materials. evenly mixed. In the primary mixer 3, the mini pellets 7 are mixed with other sintering raw materials, and as described above, the mini pellets 7 of the present invention have moisture absorbed by the powdered serpentine 8, which improves their strength. Therefore, the strength capable of withstanding the above-mentioned concentrated mixing was ensured without increasing the blending ratio of expensive bentonite, and the state in which the mini pellets 7 were crushed in the primary mixer 3 did not occur at all. The agglomerated raw materials mixed in the primary mixer 3 are discharged to the belt conveyor 9a, followed by the belt conveyor 9b and the surge hopper 1.
0a, lob to secondary mixers 11a, 11b, and after being granulated, it is fed to sintering machines 14a, 1 via belt conveyor 2, charging hoppers 13a, 13b, etc.
4b.

The sintering raw material sent to the sintering machines 14a and 14b is ignited in the upper layer, and as the burning bed advances, it is sequentially fired from the upper layer to the lower layer to become sintered ore and sent to the burning machine. 14a
, 14b. By the way, mini pellet 7 is made by firing and granulating the aforementioned gas ash, collected dust, converter dust, etc.
contains coke breeze as fuel, usually 5 to 20
% carbon C. Since the carbon in this mini-bellet burns by emitting high heat during the firing process, the serpentinite adhering to the surface of the mini-bellet can efficiently receive the high heat, melt quickly and reliably, and react. Start. In particular, since the mini-berets 7 are evenly distributed among the other sintering raw materials as mentioned above, the serpentinite 8 attached to the surface reacts evenly throughout the sintering raw materials, reducing its reactivity. It has become possible to increase significantly. Next, specific examples of the present invention will be described.

Example In the sintering equipment shown in FIG.
day (total of two sintering machines 14a and 14b) produced Akatsuki ore.

Table 1 shows the types and blending amounts of scale raw materials in this example, Table 2 shows the main components of mini-vellets, and Table 3 shows the particle size structure of serpentinite. Table 1, Table 2, Table 3, and Figure 5 show the pre-treatment method of the present invention and the conventional pre-treatment method (mini-vellets and powdered serpentinite are not roughly mixed, and the mini-vellets are mixed with the primary mixer 3). After exiting, the powdered serpentinite is fed to the primary mixer 3 along with other sintering raw materials), and the scale tin product yield, SI (shutter strength), and RD1 (reduction powdering) are stored on the belt conveyor 9a. index), basicity (Ca○/Si
02), as well as the amount of coke blended, the basic unit of coke, and the blended ratio of bentonite, etc., were investigated on a daily basis, and their changes are compared and shown in a chart.

[FIG. 5a is the conventional method, FIG. 5b is the present invention]. As is clear from FIG. 5, it was possible to significantly improve the RDI of sintered ore, which has an important effect on hot properties, and the SI, product retention, and basicity became extremely stable. Furthermore, the amount of coke required to produce knee concretion of the above quality can be reduced by implementing the present invention, and the coke consumption rate can be reduced to 1.
It became possible to reduce the amount by 1k9/ton. Furthermore, by implementing the present invention, many excellent effects described below were confirmed. {1} The amount of pentonite blended in Mini Berets was able to be reduced by 0.6%.

Moisture is absorbed by the serpentinite adhering to the surface, hardening the surface of the mini-vellet and improving its strength, making it possible to reduce the amount of pentonite encroachment.

This means that the belt conveyor 9a after leaving the primary mixer 3
As a result of the visual inspection, it was confirmed that there was no fracture of the mini-vellets at all, and that serpentinite particles were evenly adhered to the surface of the mini-vellets as shown in Fig. 3. ■ Dust generation and ore fall due to the use of powdered serpentinite were prevented.

As described in detail above, although the present invention has a simple configuration, its industrial effects are extremely large.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention. Figure 1 is a plan layout of a sintering factory, Figure 2 is a cross-sectional view taken along line A-A in Figure 1, and Figure 3 is a mini-bellet and a special powder. FIG. 4 is a cross-sectional view showing a rough mixing state of serpentinite, FIG. 4 is a cross-sectional structural view showing another example of rough mixing, and FIG. 5 is a chart showing the effects of the present invention. 1: Granulator, 2: Storage hopper, 3: Primary mixer, 4a
, 4b: Ore storage hopper, 5a to 5f, 9a, 9b, 12
: Belt conveyor, 6a, 6b: Pan conveyor, 7: Mini pellet, 8: Powdered serpentine, 10a, 10b: Surge hopper, 11a, 11b tertiary mixer, 13a, 13
b: Charging hopper 1, 14a, 14b: Sintering machine, 20: Chute, 21: Shelf. Juice l figure outside Z figure 3 figure soup 4 figure 65 figure

Claims (1)

[Claims] 1. A predetermined amount of finely divided serpentinite is supplied onto the layer of unburned carbon-containing mini-pellets during transportation and mixed roughly, and then the mini-pellets are mixed with other sintering raw materials other than serpentine to increase the reactivity of the serpentine. A method for pre-processing sintering raw materials, which is characterized by producing sintered ore with excellent hot properties.