JPS6089526A - Production of sintered ore - Google Patents

Abstract

PURPOSE:To improve productivity, coke consumption, quality, etc. in production of sintered ore by drying raw material for sintering by a part of waste gas in a surge hopper and drying further the material by the balance of the waste gas before the ignition furnace in a pallet. CONSTITUTION:A sintering machine 1 which produces sintered ore by charging raw material for sintered ore from a surge hopper 3 for charging raw material via a roll feeder 12 into the pallet on a conveyor 2 and burning the fuel in the raw material while conveying said material. 40-70% waste gas of a high temp. is blown from a gas ejecting pipe 4 into the hopper 3 of the above-mentioned sintering machine to dry the sintering raw material (m) which is kneaded to form coarse spurious grains to about 2.5% moisture content. The dried material (m) in the pallet is dried by the balance of the waste gas blown into a preheating chamber 6 before an ignition furnace 5 down to about 1% moisture content. The air permeability of the raw material for sintering is improved. Productivity is improved by preheating of said material and economization of ignition fuel is resulted from the improved ignitability. The improvement in the quality of the upper layer part is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore, and more specifically, improves the permeability of the raw material layer in a pallet by minimizing moisture content while maintaining the pseudo particles of the sintered raw material. The present invention relates to a method for producing sintered ore that improves production rate, reduces coke consumption, and improves quality.

In a method for producing sintered ore using a so-called Dwight Lloyd sintering machine, sintered raw material is supplied to the pallet from a surge hopper provided at the starting end of an endlessly driven pallet, and the sintered raw material is fed into the ignition furnace. As it passes through the pallet, the surface is ignited, and air is taken in from the wind box installed below the pallet, and sintering progresses while ventilating from the top to the bottom of the raw material layer (packed bed), and as it approaches the terminal end, the sintering continues. Since the sintered ore is discharged from the end after completion of sintering, the quality of the production rate for sintered ore production, the reduction of coke consumption per unit, and the quality of quality are greatly influenced by the combustion of the raw material layer. The quality of combustion depends on how well the air permeability of the packed bed is improved, and if the air permeability of the packed bed is poor, sintering will be delayed and the production rate will be reduced.

For this reason, conventionally, raw materials of various names are mixed before storing the sintering raw materials in the surge hopper described above. At this time, the moisture content of the raw materials is adjusted to 4 to 5% (external number) K, in order to uniformly mix various name raw materials and to create so-called pseudo-particles in which fine powder raw materials adhere to each other and become coarse particles. This promotion of pseudo-grain formation is effective in improving air permeability at the raw material stage, but once sintering begins, it causes ventilation inhibition.This is not due to the pseudo-grain formation itself being bad; When 4 to 5% of the moisture adjusted to promote oxidation remains and the surface of the packed bed is ignited to proceed with sintering, the moisture from the upper layer becomes steam and cools as it descends to the lower layer, and the steam condenses as moisture again. This is because they form a wet zone and impede air permeability.

As a result of the above, after adjusting the moisture content and creating pseudo particles, reducing the moisture content will lead to an improvement in the production rate (shortening the sintering time due to improved air permeability), but it will dry out unnecessarily. This results in the disintegration of the pseudo-particles that have been created, and the drying method is extremely heavy-duty.

Conventionally, as a method to solve such problems, the following methods were used: ■ Prior to ignition, exhaust gas at around 600°C was
A method in which the material is preheated and dried by passing through a current for 0 to 60 seconds, then ignited and sintered (%KAI No. 73834/1983), or ■ Hot air is blown into a surge hopper to achieve a dry moisture removal rate of 4%.
The following method was used, but in the former method, drying only in front of the ignition furnace,
Since drying proceeds from the upper layer to the lower layer, there is a problem that moisture condenses as it goes to the lower layer, impeding the improvement of air permeability through drying.Also, drying using only the surge hopper in the latter case results in uniform drying, but when drying on the sintering machine pallet. There is a problem in that the upper layer is not sufficiently dried when the ore is fed, resulting in a decrease in the cold strength of the upper layer and an increase in the amount of ignition heat.

By the way, the quality of sintered ore, especially the quality in the thickness direction of the packed bed (
Cold strength TI and reduction powder resistance RDI) are relatively good in the lower layer and relatively poor in the upper layer. this is,
This is believed to be because the upper layer has little thermal compensation during the sintering process, and a sufficient sintering reaction does not take place. Therefore, the quality should be improved by sufficiently heating the surface of the pressure packed bed before ignition and igniting to sufficiently compensate for the heat.

The present invention has been made in view of the conventional problems and the above viewpoints, and its purpose is to reduce the disintegration of pseudo particles by drying in two stages both in the surge hopper and in the pallet. The purpose is to sufficiently remove moisture from the sintering raw material without causing any damage and improve air permeability, thereby increasing production rate, reducing coke consumption, and improving quality.

The method for producing sintered ore according to the present invention involves mixing sintering raw materials to coarsen pseudo particles, and then blowing 40% to 70% of high-temperature exhaust gas into a surge hopper to dry the sintered raw materials in the surge hopper. After charging the dried sintering raw material into a sintering machine pallet, the remaining hot air is blown into the pallet in front of the ignition furnace to dry the sintering raw material within the pallet.

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

In Fig. 81, a gas jetting vibrator 4 inserted into the lower part of a material charging surge hopper 3 provided at the upstream end of the pallet conveyor 2 of the sintering machine 1 and a preheating chamber 6 provided at the upstream side of the ignition furnace 5 are shown. It is connected via conduits 7 and 8, respectively, to an exhaust gas conduit 9 of a cooler (not shown) of the sintering machine. Dampers 10 and 11 are provided in the dedicated pipes 7 and 8, respectively, so that the flow rate of the exhaust gas flowing into the pipe 7 is 40% to 70% of the flow rate flowing through the pipe 9, and the flow rate of the exhaust gas flowing into the pipe 8 is the remaining. The sintering machine is operated under these conditions, and the surge hopper 6 is
The sintering raw material m, which has been made into pseudo particles, is charged into the surge hopper, and cooler exhaust gas is blown into the surge hopper from the gas jet pipe 4. This cooler exhaust gas has a sensible heat of 1008C to 300°G, and the amount of air blown into the surge hopper is 40% to 70% of the total. Due to the sensible heat of this hot air, the raw material is dried until the moisture content becomes approximately 2.5% while maintaining its quasi-particulate state. In addition, the water content is 2.
The reason for setting the upper limit to 5% is that, as shown in Figure 2, drying up to that point has a significant effect on improving air permeability, but drying below this level does not significantly improve air permeability, and also because it is difficult to load onto pallets. This is to prevent the pseudo particles from collapsing upon entry.

Next, the sintering raw material m dried as described above in the surge hopper 6 is charged into a pallet of the pallet conveyor 2 via the roll feeder 12. Next, when the pallet is moved and passes under the preheating chamber B, the exhaust gas blown into it flows from top to bottom inside the pallet due to the suction action of the wind box 14 thrown below the pallet conveyor, and the pallet is The upper layer of the raw material layer inside the container should be dried. Through this drying, the raw material in the upper layer is dried to a moisture content of 1% or less. The pallet is then ignited as it passes under the ignition furnace.

At this time, there is almost no moisture, and the hot air reduces the raw material to 100%.
Since it is preheated to 600°C to 600°C, the ignitability is good, making it possible to reduce the amount of ignited fuel and improve the quality of the upper layer.

In addition, the hot air volume ratio blown into the surge hopper is 40%.
The reason for limiting the moisture content to 70% is to ensure the amount of heat necessary to dry the raw material moisture down to 2.5%.

In order to clarify the effects of the present invention, (1) a method of blowing the entire amount of cooler exhaust gas before the ignition furnace (conventional method ■), (2) a method of blowing the entire amount of cooler exhaust gas into the surge hopper (conventional method ■), and (3) ) After blowing 60% of the cooler exhaust gas into the surge hopper and drying the moisture to 2.5%, the remaining 40% is sent to the ignition furnace.
As a result of testing on the method of drying the upper layer of raw material moisture to 0.5% (method of the present invention) by blowing in, the following solution 1 was shown.

Table 1 In this test, C gas was used as the ignition heat source, the thickness of the charged material was 500 mm, and the pallet speed was 1.51 minutes.

As is clear from Table 1, in the comparison of conventional methods ■ and ■,
From the viewpoint of production rate and coke consumption, method (2) is preferable because drying is carried out uniformly, but method (2) results in an increase in the amount of ignition heat because the degree of dryness in the upper layer decreases. Furthermore, since the strength of the upper layer deteriorates, the TI of the finished product decreases. On the other hand, in the method of the present invention, the upper layer is further dried after uniform drying, which eliminates the drawbacks of the conventional method (■) and reduces the production rate compared to the conventional method (■■).
Improves both coke consumption and C gas consumption quality.

In addition, in the above explanation, we have described the case where sintering machine cooler exhaust gas is used as the high-temperature exhaust gas, but it is not limited to cooler exhaust gas, and any high-temperature exhaust gas such as sintering exhaust gas or combustion exhaust gas can be used. Further, it is preferable that the exhaust gas temperature is 100 to 600°C because the raw material can be efficiently dehydrated, but it is not necessarily bad if the exhaust gas temperature is outside this range.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing a method for manufacturing sintered ore according to the present invention, and FIG. 2 is a diagram showing the relationship between moisture content and air permeability of sintered ore. Patent applicant Sumitomo Metal Industries, Ltd. Kinsha (4 others)

Claims (1)

[Claims] After kneading the sintering raw material to coarsen the pseudo particles, 40% to 70% of the high-temperature exhaust gas is blown into the surge hopper to dry the sintering raw material in the surge hopper, and the dried sintering raw material is sintered. A method for producing sintered ore, which comprises charging the sintered ore into a machine pallet and then blowing remaining hot air into the pallet in front of an ignition furnace to dry the sintered raw material in the pallet.