JPS5864326A - Supplying method for sintering raw material - Google Patents

Abstract

PURPOSE:To produce quicklime inexpensively in the stage of compounding sintering raw materials and to make the same suppliable as a sintering raw material to sintering machines by mixing the quicklime, which is formed by mixing lime powder and powder coke and adding hot return sinters to the mixture, with other sintering raw materials. CONSTITUTION:Part of lime powder 2 is discharged partly from a lime powder hopper and part of powder coke 6 is discharged from a coke hopper. Both are beforehand mixed 8. The mixture is supplied to hot return sinters 5 and the lime powder 2 in the mixture is decarbonized by the sensible heat of the fines 5 and the combustion heat of the coke 6, thereby forming a required quantity of quicklime. Respective specified quantities of fine ores 1, lime powder 2, cold return sinters 4, hot return sinters 5 contg. said quick lime, and the coke 6 which are sintering raw materials are cut out from respective raw material hoppers and after these materials are mixed under feeding of water in a mixer, the mixed materials are supplied to sintering machines.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for supplying sintering raw materials to a sintering machine. A conventional method for supplying sintering raw materials will be explained with reference to FIG. A predetermined amount of sintering raw materials such as ore powder 1, lime powder 2, quicklime 3, cold return ore 4, hot return ore 5, and coke powder 6 are cut out from each raw material hopper and mixed with water in a mixer (7).
Then it is fed to the sintering machine.

When quicklime is used as a sintering raw material, it is possible to increase the production rate due to improved granulation properties and to reduce the conversion rate of nitrogen (N) to nitrogen oxides (NOX) due to water utilization reactions. However, the current quicklime is very expensive due to its manufacturing method, and adding quicklime to the product increases the cost of producing sintered ore, which is not desirable.

Therefore, an object of the present invention is to produce quicklime at a low cost in the sintering raw material blending process and to be able to immediately supply it to a sintering machine as a sintering raw material. Lime powder and coke powder are taken out and mixed together, this mixture is added with thermal return ore, which is a raw material for sintering, and the lime powder is decarboxylated using the sensible heat of the thermal return ore. It is characterized in that the quicklime is mixed with other sintering raw materials and then supplied to the sintering machine.

Next, a specific method of the present invention will be explained with reference to FIG. In the method of the present invention, quicklime is not supplied from a dedicated raw material hopper, and after adding a mixture of lime powder and coke powder to the thermal return ore as a substitute for quicklime,
The difference is that it is blended into the sintering raw material.

Thermal return ore is generated in the ore discharge section of the sintering machine when the fired lump sintered ore is roughly crushed into a predetermined size suitable for blast furnace charge, and it has a particle size of 6. Below,
and 100% for high-temperature items immediately after firing.
It has a temperature of 0 to 1400'C, and the amount generated is equivalent to 10 inches of sintering raw material. Conventionally, such thermal return ore was left as it is without using its sensible heat.
It was simply mixed with fine ore, auxiliary raw materials, and other plug coke and used as a raw material for sintering.

In the present invention, the average temperature is 700°C, and some parts are about 140°C.
In the method of the present invention, the purpose is to obtain quicklime powder of 1 to 3 qID to be added to the sintering raw material from lime powder by utilizing the sensible heat of thermal return ore at a high temperature of 0°C. 2~
A portion of lime powder corresponding to 5 wt% was taken out from the lime powder hopper, and 10 to 20 w of lime powder 2 was removed from the lid.
A portion of coke powder in an amount corresponding to t% is taken out from the coke hopper and mixed in advance (8), and this mixture is supplied to the thermal return ore 5 corresponding to about 10 g of the sintering raw material.

The lime powder in the mixture is decarboxylated by the sensible heat of the thermal return ore 5 and the combustion heat of the coke powder, and the lime powder used in an amount of 2 to 5 wt% of the sintering raw material becomes quicklime of 1 to 3 wt%. This reaction is shown in the following formula.

CaC03=CaO+CO2↑ The quicklime thus generated during thermal return ore is mixed with other raw materials and performs its original function.

The reason why the amount of pre-mixed lime powder used is 2 to 5 wt% of the sintering raw material is that the quicklime powder to be generated is 1 to 3 wt% of the sintering raw material.
This 1 to 3 wt% quicklime powder is used as a substitute for conventional quicklime to promote pseudo particles and reduce N in exhaust gas.
This is because it is effective in reducing Ox.
The reason for setting it to 20 wt% is that the amount of coke breeze is sufficient to add heat in addition to the sensible heat of the hot return ore, and when the amount of hot return ore added is relatively small, ,
When a large amount of coke breeze is mixed and the amount of thermal return ore added is relatively large, a small amount of coke breeze may be mixed, and a coke breeze mixing amount of 10 to 20 wt% of the mixed lime powder is most suitable. Because it became clear. It should be noted that even if the mixture of lime powder and coke powder does not undergo a complete reaction, there is no problem because it becomes part of the sintering raw material.

Table 1 shows the results of applying the method of the present invention to an actual machine. In this example, the total sintering raw material (fine ore ten lime powder + cold return ore +
A mixture of 3 wt% of lime powder based on the sintering raw material and 15 wt% of coke based on the lime powder was added to the thermal return ore generated at 10 wt% based on the thermal return ore + powdered coke.
In the conventional method, ore powder, lime powder, cold return ore, hot return ore, coke powder, and quicklime were simultaneously mixed in a mixer and fed to the sintering machine as the sintering raw material.Table 1 shows the raw materials. Table 1 shows the results when fired in a sintering machine.According to the method of the present invention, the same quality of sintered ore as before can be obtained, while the quicklime produced in the conventional shaft furnace etc. can be transported by tank lorry. However, the charging process using means such as pneumatic transportation can be significantly streamlined, and the manufacturing cost of sintered ore can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional sintering raw material supply method. FIG. 2 is an explanatory diagram showing the sintering raw material supply method of the present invention. Patent applicant: Sumitomo Metal Industries, Ltd. (2 others)

Claims (1)

[Claims] In the method of mixing powdered ore with other necessary raw materials and supplying the obtained sintering raw material to a sintering machine, mixing lime powder and coke powder, which are sintering raw materials, and mixing the mixture and sintering raw materials. A method for supplying a sintering raw material, which comprises: adding hot return ore, and mixing quicklime generated by the sensible heat of the hot return ore with other sintering raw materials, and then supplying the mixture to a sintering machine.