KR930006812B1 - Raw coal mixture method - Google Patents

Abstract

The source coal mixing method for metallurgical cokes comprises (a) increasing the total amount of an inert component from 25.5 % to 32.6 % against 2.6 log ddpm of a fluidity, (b) increasing the fluidity by 0.05 log ddpm according to increasing the total amount of an inert component by 1 %, and (c) maintaining the total expansion rate in range of 100-200 %.

Description

Blending method of raw coal for the manufacture of coke for metallurgy

The present invention relates to a method of blending raw coal in metallurgical coke production, and more specifically, a large amount of coal having a high total amount of inert components (Total Inert, hereinafter referred to as TI) is blended and the average properties of the coal blended. To control the blending of raw coal when TI increases.

Among the types of coal classified as anthracite, bituminous coal, lignite, and atan, only bituminous coal can be used as steel for coal, and when the bituminous coal is dried, coal particles bind to each other unlike anthracite, lignite, and coal to form coke. .

On the other hand, the proportion of the bituminous coal in coal resources is very low, and in the case of Korea, bituminous coal is not produced at all, and thus, the total amount of raw coal for metallurgical coke production is dependent on imports from overseas. By the way, the quality of raw coal to produce coke in coal resources is gradually being depleted and the quality of ash and TI is deteriorating.

Therefore, in the method of manufacturing coke by combining coal of 9-12 coal species, when these coals are blended, the TI of the coal is naturally increased, resulting in a decrease in the quality of the coke.

Usually, metallurgical coke is charged with iron ore into the blast furnace, and it is a breathable retaining material that allows the inferior inlet to the blast furnace to be well vented to the upper part, a reducing material for reducing iron ore, and a heat source for providing heat for iron ore reduction reaction. In order for the coke to fully fulfill this role, the coke must satisfy the quality requirements in Table 1 below.

TABLE 1

As described above, the metallurgical coke is made of coke after 9-12 carbon raw materials are mixed at a ratio of 25% of hard coal, 50% of semi-coal coal, and 25% of weak coal, and dried for 16-17 hours. In order to make the coke of the same quality is formulated into a compounding range as shown in Table 2.

TABLE 2

* CBI: Composition Balance Index

SI: Stregth Index

RM: mean reflectance of coal

TI: Total Inert

However, conventionally, even if the properties shown in Table 2 are maintained, when coke is manufactured, deterioration and variation of the coke quality required for the blast furnace operation of Table 2 frequently occur, thereby often hampering pig iron productivity. For this reason, the relationship between the other properties of coal as shown in Table 2 cannot be considered. Second, the use of poor quality raw coal is increased due to supply instability due to depletion of raw coal resources for coke production. The compounding property of the coal briquettes, such as TI of the coal briquettes in which -12 coal type coal was mix | blended, is bad. In fact, in the blending of the coking coal for coke production belonging to the blending range shown in Table 2, the coke produced from the coal briquettes having a flow rate of 2.3 and TI20% and a flow rate of 2.8; Coke made from coal briquettes of TI30% exhibits a difference in quality. Accordingly, an object of the present invention is to quantify the relationship between these blending index in the coal blending properties, even if the coal with a high TI in the coal blended to increase the TI of the coal blended metallurgical for maintaining the quality of coke as shown in Table 1 It is to provide a method of blending coke raw coal.

In order to achieve the above object, the present invention, in the blending method of the raw coal used in the manufacture of coke for metallurgy, each time the TI of the blended coal is increased by 1% based on TI25.5% flow rate 2.6log ddpm, It is characterized in that the raw coal is blended to increase 0.05log ddpm and maintain the total expansion within the range of 100% -120%.

Hereinafter, the general conditions of the present invention and the reason for numerical limitation will be described in detail.

When the TI is increased by 25.5% or more, when the total expansion ratio is 120% or more in the mixed carbon property, the coke structure is increased in the coke structure, which is caused by severe shrinkage expansion in the process of carbonizing the mixed coal during heating to produce coke. If the strength is lowered to less than 100%, the coking coal produced is insufficient when the coal is carbonized, and thus the coke produced is lowered. Therefore, when the TI25.5% or more is increased, the total expansion is 100-200%. desirable.

In addition, when the TI of the coal briquettes is increased, if the flow rate is higher than necessary, the viscosity is low during coal carbonization, so that the bonding with coal particles is not promoted. It is desirable to increase the flow rate by 0.05 log ddpm when the TI1% is increased because coal particles are not sufficiently melted and strong substrate coke is not produced.

Example 1

The coke was manufactured by mixing the raw coal in the coke oven as shown in Table 3 below, using TI, fluidity, total expansion, and average reflectance as a compounding index. Here, the comparative example shows the case out of the scope of the present invention.

TABLE 3

The cold strength and the post-reaction strength of the coke thus produced were measured and shown in Table 4 below.

TABLE 4

According to Table 4, in the case of Inventive Examples (a, b, c) belonging to the blending standard of the present invention, the coke quality standard of Table 1 was satisfied, but in the case of Comparative Examples (1, 2) outside the blending standard, It can be seen that the quality is less than the standard, in particular, in the case of Comparative Example 1, the coke quality does not meet the standard of Table 1, even though the formulation of Table 2 is satisfied. As in Comparative Examples (1, 2), if one of the quality of the coke is either cold strength or the strength after the reaction, when coke that is insufficient is charged into the blast furnace, the coke is rapidly differentiated in the blast furnace, leading to a decrease in the air permeability of the blast furnace and productivity. Degrades.

Example 2

In order to compare the change of coke quality and the properties of coking coal by gradually increasing the TI of coking coal, coking is performed by mixing TI, flow rate, total expansion, and average reflectance with coking index as shown in Table 5 below. Was prepared.

TABLE 5

The cold strength and post reaction strength of the coke thus prepared were measured and shown in Table 6 below.

TABLE 6

In Table 6, results similar to those of Table 4 were obtained. Inventive Example (d, e) in Table 6 was a result of satisfying the blending criteria of the present invention while belonging to the blending range of Table 2, and Inventive Example f. And Comparative Example 3 shows the results in the case of falling outside the range of Table 2, according to Table 6 it can be seen that the coke quality of the invention examples (d, e, f) is more than the standard of Table 1, Comparative Example 3 The coke quality of is lower than the standard for both cold and post reaction. In addition, when blended according to the blending standard of the present invention, even if TI exceeds the blending range of Table 2, the quality of coke is maintained in the same range as in Table 1 above, up to 32.6% of TI of Inventive Example (8). It can be seen that the metallurgical coke that satisfies the criteria of Table 1 can be prepared.

As described above, according to the present invention, when coal with high TI is blended into the coal blend, the coal blend prevents the quality of the coke from deteriorating due to the increase of the TI on the average property, and the upper limit of the TI of the coal blend is higher than before. Since it can be managed from 30% to 32.6% higher than conventionally, the low cost TI can increase the use of high coal to reduce the coke manufacturing cost.

Claims (1)

In the method of blending raw coal used in the manufacture of coke for metallurgical coke, the TI of the blended coal is increased to 32.6% based on the total inert (TI) of 25.5% and the flow rate of 2.6 log ddpm in the coke oven. The raw material coal blending method for manufacturing metallurgical coke, characterized in that to increase the flow to 0.05log ddpm increase and maintain the total expansion in the range of 100-200%.