JPS5814492B2 - shouketsukounoseizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to absorb the condensed moisture that obstructs the air permeability of the lower layer of the sintered layer, the present invention uses a moisture absorbent such as quicklime in the lower 75% of the total layer thickness. This invention relates to a method for producing sintered ore that is added to the lower layer to reduce the condensed moisture in the moisture condensation zone of the sintered layer and improve the permeability of the sintered layer, thereby significantly improving the productivity of the sintering machine. be.

The range of the lower layer to which the moisture absorbent is added must be at least 30% from the bottom, but if it is added in excess of 75%, no effect commensurate with the addition will be obtained.

In the commonly used Dwight Lloyd type sintering machine, the surface layer of the blended raw materials is ignited in the ignition furnace, and the combustion within the raw material layer gradually moves from the surface layer to the lower layer, and the entire sintering reaction process takes about 15 to 30 minutes.
It takes about 16 minutes to complete.

Since the productivity of sintered ore is greatly influenced by the sintering time, it is very important to ensure and improve the permeability of the raw material layer.

Therefore, in sintering factories, various actions are taken to improve the granulation properties of the sintered compound raw materials, ensuring air permeability of the sintered layer, and operating methods to improve productivity.

For example, quicklime,
A known method is to add a flocculant such as slaked lime so that the fine ore does not exist alone, but is attached to other ores to form good pseudo-particles and improve air permeability.

That is, in the conventional method, the air permeability of the sintered layer is ensured by increasing the granulation properties of the sintered compound raw materials, thereby improving productivity.

However, no matter how much the granulation properties of the sintered mixed raw materials are improved, the moisture condensation zone in the sintered layer that is formed after the surface layer of the mixed raw materials is ignited in the ignition furnace is affected by the ventilation of the sintered layer. Although it is clear from the results in Figure 4 that this significantly impedes sexual performance, no measures have been taken to prevent it.

Therefore, the present invention aims to solve the above problem by preventing the formation of a moisture condensation zone that significantly impairs the air permeability of the sintered layer when it is loaded into a sintering machine.

The details of the present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the invention.

Figure 1 shows a two-stage charging operation, in which the sintered compound raw materials in the upper layer of the sintering bed are transported to the primary mixer 2 by a belt conveyor 1, and are slightly moistened by a water sprinkler 3 in the primary mixer. It is added, mixed and granulated.

Furthermore, it is transported to a secondary mixer 5 by a belt conveyor 4, and is granulated with sufficient water added by a water sprinkler 6 in the secondary mixer.

Thereafter, it is transported by belt conveyors 7, 8, charged into a surge hopper 9, placed in the upper part of a sintering bed, and then sintered in a sintering machine 10.

Further, the sintered blended raw materials in the lower layer of the sintering bed are transported by a belt conveyor 1' to a primary mixer 2', and are mixed and granulated with water added thereto by a water sprinkler 3' in the primary mixer.

Furthermore, the water absorbent is transported to the secondary mixer 5' by the belt conveyor 4', water is added and granulated by the water sprinkler 6' in the secondary mixer, and then the moisture absorbent is transferred to the belt conveyor in the latter half of the secondary mixer 5'. 11.

After that, the surge hopper is transferred to the belt conveyor 8'.
9' and the lower part of the sintering bed, and then sintered in the sintering machine 10.

In other words, in this method, the mixed raw materials are charged into the sintering machine in two stages, and in the lower layer where the moisture condensation zone is particularly formed, a moisture absorbent is attached to the surface of pseudo particles and charged. It is something that forces you to do something.

The method of adding a moisture absorbent to the lower layer of the sintering bed is not limited to the method shown in FIG.

An example of another method will be explained with reference to FIG.

The raw materials for sintering in the surge hopper 12 are dropped onto the sloping plate 14 by the drum feeder 13 and then charged into the sintering machine. Water condensation is caused by spraying a moisture absorbent 15 onto the charged raw materials. Zone formation can be prevented.

Even if this method is implemented, productivity can be expected to be improved by improving the air permeability of the sintered layer, as in the method shown in FIG.

The moisture absorbent is not limited to quicklime, and other water absorbing substances such as limonite or return ore, silica gel, etc., which have high moisture absorption properties, may be used.

Figure 3 shows an example of measuring the moisture condensation zone of the sintering bed.

The layer height (mm) is plotted on the vertical axis and the condensed moisture (%) is plotted on the horizontal axis, and it can be seen that in the case of Example 1, the formation of a moisture condensation zone is prevented.

FIG. 4 shows an example of measuring the ventilation resistance of the moisture condensation zone.

The vertical axis shows the ventilation resistance coefficient KP, and the horizontal axis shows the condensed moisture (%).As the condensed moisture (%) increases, KP'
It is clear that there will be an increase in

Note that the ventilation resistance coefficient KP' is a proportionality constant expressed in logarithm on the assumption that the pressure loss (ΔP) of the sintered bed layer is proportional to the n-th power of the effective air volume (u).

Next, the present invention will be explained in detail with reference to examples.

Table 1 shows the blending ratio of the raw materials used in this experiment, and Table 2 shows the particle size distribution of the raw materials.

The blended raw materials are various iron ores, limestone, scale and other miscellaneous raw materials, and the SiO2 and Al2O3 in the sintered ore are 5% each.
．． 60%, 2.00%, and the basicity is 1.
．． It was blended so that it was 30.

In addition, the return ore content ratio is set at 20%.

As for other experimental conditions, the coke blending ratio was 3.84.
%, which is the optimum value for the above blended raw materials.

In the experiment, coke, return ore, and added water were blended with the above blended raw materials, mixed in a mixer, and sintered in a 40 kg test pot.

The experimental conditions in this case were that the suction negative pressure was 1500% Aq and the ignition time was 1.5 minutes.

In Example 1, the moisture absorbent was added using quicklime, and the addition method was as follows:
A method was adopted in which it was added in the second half of the next mixer.

It should be noted that a sufficient effect was obtained with the addition rate of quicklime of about 0.5% to the whole layer, and even if more than that was added, the production rate remained almost the same or even tended to worsen.

The results of production rate, sintering time, product yield, and drop strength obtained in Comparative Example and Example 1 are shown in Table 3 and FIG. 5.

As a reference example, the results of mixing quicklime into the blended raw materials before the primary mixer and granulating them are also shown.

In both Example 1 and Reference Example, the quicklime addition rate was 0 for the entire layer.
．． It is 5%.

From Table 3 and Figure 5, it is clear that if a sintering method that reduces the moisture condensation zone in the sintering bed is implemented, the sintering time will be significantly shortened and the production rate will be improved, especially when the moisture content is high. The effect becomes more pronounced as the operation progresses.

Further, no change was observed in yield and strength.

Figure 6 shows the results of a factory experiment (Example 2) in which the method of the present invention was implemented.
).

The experiment was conducted using a sintering machine with a daily capacity of 10,000 tons, and the period was 10 days.

The experimental method was carried out as shown in Figure 2, with the addition rate of quicklime being 0.5% to 1.0%, and the lower half of the total thickness being 400 mm.
Added to mm.

According to the experimental results, productivity was significantly improved, and no adverse effects on product yield, sintered ore quality, coke consumption, etc. were observed.

As described above, in the present invention, a moisture absorbent is added so as to be attached to the particle surface of a mixed and granulated sintering raw material, that is, a pretreated sintering raw material, and furthermore, the moisture absorbent is When charging the sintered raw material into the sintering machine,
Since the above-mentioned moisture absorbent is present in a layer height range of at least 30% or more from the bottom of the charged sintered raw material layer, it is generated by igniting the surface of the sintered raw material layer and sucking air downward for sintering. The condensed moisture at the bottom of the sintered raw material layer is captured by the moisture absorbent adhering to the surface of the sintered raw material particles, and this suppresses the increase in moisture in the aggregated particles. This greatly reduces the problem of obstruction to the air permeability of strata.

As a result, the sintering time can be significantly shortened and productivity improved. Also, when iron ore with high water absorption is used, high moisture operation is required and moisture condensation zones are more likely to be formed. The effects of the present invention are particularly significant.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention in the case of two-stage operation. FIG. 2 is an explanatory diagram of an embodiment of the present invention. FIG. 3 is a diagram showing the measurement results of the moisture condensation zone. Figure 4 is a diagram showing the relationship between condensed moisture (%) and ventilation resistance. FIG. 5 is a diagram showing the influence of the present invention on pre-production rate, sintering time, product yield, and drop strength. Figure 6 shows the production ratio, product yield, sinter quality, and
A diagram showing the influence on coke consumption rate.

Claims (1)

[Claims] 1 When adding an absorbent for condensed moisture that inhibits the air permeability of the sintered layer, the mixture and granules are mixed and granulated so that the area where the moisture absorbent is added is at least 30% from the bottom of the sintered raw material layer. A method for producing sintered ore, characterized in that formation of a moisture condensation zone in sintered sow is suppressed by attaching a moisture absorbent to the surface of sintered raw material particles.