JPH03229792A - Production of coke for iron making - Google Patents

Abstract

PURPOSE:To improve the hardness of coke by adding a mixture comprising a nonionic surfactant and a sulfonic acid-based surfactant to coking coal in the production of coke for iron making by carbonizing coal in a coke oven. CONSTITUTION:Nonionic surfactants such as polyoxyethylene alkyl ethers or propylene glycol fatty acid esters and sulfonic acid-based surfactants such as alkylbenzene sulfonic acid or alkylnaphthalene sulfonic acid are mixed. Then, the mixture is added as a quality modifier to coking coal before fed into a coke oven. Carbonization gives coke with an improved coke hardness for iron making. The surfactant mixture should adequately be added in an amount of 0.1-1wt.% based on the coking coal. In respect of the time of addition, a marked effect can be achieved when the surfactant mixture is added just after the grinding of the coking coal on a coal grinder.

Description

[Detailed Description of the Invention] "Object of the Invention" (Industrial Application Field) This invention relates to a method for producing coke for steelmaking, and in particular to improving the quality of coking coal charged into a coke oven. .

(Conventional technology) Coke for steelmaking is produced by pulverizing raw material coal mixed and prepared in a blending tank using a coal crusher, thoroughly mixing it using a coal blender, charging the coal into a coke oven, and carbonizing it. .

In addition, in recent years, large-scale blast furnaces require particularly high-strength coke, so highly caking coal with a low volatile content is mainly blended with low-rank coal. Moreover, in order to reduce costs, a method is desired that maintains this coke strength, reduces the amount of highly caking coal used, uses as much low-grade coal as possible, and does not reduce coke strength.

One such method is to increase the bulk density of raw material coal when charging it into a coke oven, thereby increasing the bulk density of produced coke and giving it strong caking properties. 10089
2 or as shown in JP-A No. 61-283685, coke is produced by adding a chemical whose main component is an anionic surfactant having a sulfone group in the molecule to increase the bulk density of raw coal. It is proposed to do so.

(Problems to be Solved by the Invention) In the conventional technology as described above, anionic surfactants having a sulfone group in the molecule have the effect of improving the bulk density of raw coal, and the strength of the coke obtained as a result is However, the high temperature fluidity of raw coal is reduced due to the high thermal reactivity of the sulfone group. Therefore, even if the bulk density is mechanically increased, the relative coke strength will be slightly lower, so it is desired to reduce the amount of surfactant used.

On the other hand, there are nonionic surfactants that have less such adverse effects. However, ordinary raw material coal is piled up in yards and has a moisture content of 8 to 12% by weight, and when it rains, the moisture content increases to 15% by weight or more. In the case of normal addition, the adhering water on the coal causes gelation, resulting in a poor dispersion state, and the bulk density improvement effect cannot be sufficiently exhibited in many cases. Therefore, some nonionic surfactants are water-soluble depending on their concentration. In other words, a lot of water? One possible method of addition is to dilute the coal with water in advance to reduce the effect of water adhering to the coal, but an extreme increase in the water content in the coal will lead to a decrease in bulk density and a decrease in coke strength. At the same time, this leads to an increase in the amount of heat required for carbonization, which is undesirable from the viewpoint of coke production cost.

"Structure of the Invention" (Means for Solving the Problems) The present invention was created after repeated studies to solve the problems of the conventional products as described above. As a method of reducing the amount of water or not using it at all, a sulfonic acid surfactant, that is, an organic compound having a sulfone group, can be used as a nonionic surfactant to the extent that it does not significantly affect the high-temperature fluidity of raw coal. In addition, we have invented a method that does not cause gelation due to moisture and can also be expected to have the effect of improving the bulk density of the added sulfonic acid surfactant. That is, as follows.

After adding a coke quality improver, which contains a nonionic surfactant and an anionic surfactant with a sulfone group in its molecules, to raw coal for steelmaking coke, it is loaded into a coke oven. 1. A method for producing coke for steelmaking, characterized in that the strength of the produced coke is improved by carbonizing the raw coal in a state where the bulk density is high.

(Function) As the raw material coal, various conventionally used coals can be appropriately employed. That is, various brands of strongly coking coal and weakly coking coal can be appropriately mixed and used regardless of whether it is domestic coal or foreign coal.

The nonionic surfactants that are constituent components of the coke quality improver mentioned above include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, and propylene glycol fatty acid esters. ,
Examples include propylene glycols, and those that have an HLB value of 10-15, which is a numerical value representing the hydrophilicity of a surfactant, and are liquid at room temperature are particularly preferred.

In addition, examples of anionic surfactants having a sulfonic group in the molecule that can be mixed with such nonionic surfactants include extremely common alkylbenzenesulfonic acids, benzenesulfonic acids, alkylnaphthalenesulfonic acids, and naphthalenesulfonic acids. In addition, sulfosuccinic acids and heavy oils obtained from petroleum refineries or coal tar Fujidome to which sulfone groups have been added can be used. In addition, in order to increase its ability as a surfactant, it is preferable to form salts with lithium, sodium, potassium, calcium, ammonium, etc., and particularly preferably calcium or ammonium salts that do not damage the refractories of coke ovens. good.

Such nonionic surfactants and anionic surfactants with sulfone groups may be added with a small amount to maintain the overall viscosity of the coke quality improver at a low level in order to improve dispersibility during addition. Water or mineral oil such as A heavy oil, B heavy oil, C heavy oil, etc. may be added.

The mixing ratio of the above-mentioned nonionic surfactant (N) and anionic surfactant (A) is generally (N):
(A) is 40:60 to 90:10, and the preferred range is (N):(A) is 60:40 to 80.
:20.

The amount added is preferably 0.1-1.0% by weight in the form of a coke quality improver based on raw coal.

If the amount added is less than 0.1% by weight, generally no desirable effect will be obtained, and if the amount added exceeds 1.0% by weight, the improvement in bulk density will be saturated and the coke will not have high strength. Not only is no improvement expected, but as a result, a large amount of anionic surfactant is added, which may have a negative effect due to the influence of the sulfone group. The position and timing of addition may be before or after the blending tank, but the effect will be more pronounced if it is added after the coal has been pulverized by the coal crusher.

(Example) Specific examples of the present invention will be described below.

Four types of coal crushed to 3+n or less using a coal crusher are processed according to JIS standards.
The value measured in accordance with the law is Gieseler's highest fluidity M F
= 120 D D P M, average reflectance Ro-1,
It was blended so that it was 100. Table 1 shows the blending ratio of the raw coal. This blended coal has its moisture content adjusted to 8%,
It was used as raw material blend coal for coke production.

Table 2 In addition to this, 30 parts by weight of polyoxyethylene alkyl ether with an alkyl group having 12 carbon atoms and an ethylene oxide addition number (average) of 7 as a nonionic surfactant, and di2-ethyl as an anionic surfactant. A predetermined amount of a bulk density improving aid consisting of 15 parts by weight of sodium hexylsuccinate, 5 parts by weight of methanol, and 50 parts by weight of water was added and thoroughly mixed. This sample was then heated to 260 w (W)
X, 260w (D) X 350mm (H) steel carbonization tube was placed in each case and allowed to fall naturally from a height of 500 mm twice to fill.

After measuring the bulk density of this material, it was placed in a carbonization furnace and carbonization was started. The carbonization conditions were as follows: charged in a carbonization furnace heated to 1000°C, held for 7 hours, discharged, sprinkled with water for about 10 minutes,
The fire was extinguished and cooled down.

The method for preparing the raw material blend coal for producing coke was the same as in Example 1. To this, a predetermined amount of a bulk density improving aid consisting of 75 parts by weight of sodium di-2-ethylhexylsulfosuccinate and 25 parts by weight of methanol was added and thoroughly mixed. Thereafter, coke was obtained in the same manner as in Example 1.

As a type of anionic surfactant having a sulfonic group in the molecule, the sodium salt of the sulfonated heavy oil obtained from the coal tar distillation process, that is, the sodium salt of the sulfonated coal-based heavy oil, is used as di-2-ethylhexyl sulfosuccinate. Coke was produced in the same manner as in Example 1, except that 20 parts by weight of sodium chloride and methacal were used instead of the total amount.

The method for preparing the sulfonated heavy oil sodium at this time is as follows. Coal-based heavy oil with the properties shown in Table 2 below is dissolved in carbon disulfide, a solvent, and acetone is added. Sulfur trioxide diluted with nitrogen gas is introduced and reacted, and the reaction product is The oil was recovered and the solvent carbon disulfide was removed to obtain sulfonated heavy oil. At this time, the content of sulfone groups was 38% by weight, and it was soluble in water. After dissolving this sulfonated heavy oil in water, it was dissolved in an aqueous sodium hydroxide solution with pu=6. s and water was removed to obtain sulfonated heavy oil sodium.

A sulfonated heavy oil was prepared in the same manner as in Example 2 in Table 2, dissolved in water, and adjusted to pH-6.5 with aqueous ammonia. Thereafter, water was removed to obtain sulfonated heavy oil ammonium. A coke quality improver was prepared with a composition of 40 parts by weight of the same polyoxyethylene alkyl ether as in Example 1 as a nonionic surfactant, 10 parts by weight of this sulfonated heavy oil ammonium as an anionic surfactant, and 50 parts by weight of water. Prepared. Coke was obtained in the same manner as in Example 1 except that this was used as a coke quality improver.

Regarding the results obtained in the above-mentioned Examples and Comparative Examples, the packed bulk density of the raw coal blend is shown in FIG. 1, and the drum strength of the obtained coke is shown in FIG. 2. That is, as can be seen from Fig. 1, although the examples shown here are slightly inferior to the comparative examples in terms of the bulk density improvement effect, the anionic interface having a sulfone group in the molecule has a negative effect on the high-temperature flow characteristics of the raw material blend coal. It is clear from FIG. 2 that the example in which the amount of activator added is smaller improves the coke strength.

``Effects of the Invention'' This invention uses a nonionic surfactant as a coke quality improver for raw coal blend, which has little negative effect on the coal blend, and an anionic surfactant having a sulfone group in the molecule. This invention is industrially very effective because it improves the quality of the raw coal blend by adding the additives and greatly improves the coke strength.

[Brief explanation of drawings]

The drawings show the technical content of the present invention, and Figure 1 is a chart showing the relationship between the amount of improver added and the bulk density for Examples and Comparative Examples of the present invention, and Figure 2 is also shown in this book. 2 is a chart showing the relationship between the amount of improver added and the strength of the obtained coke for Examples and Comparative Examples of the invention. Bulk drink*, kg/m3

Claims (1)

[Claims] A steel manufacturing method characterized in that a mixture of a nonionic surfactant and a sulfonic acid surfactant is added to raw coal as a quality improver when coal is charged into a coke oven and carbonized to produce coke for iron manufacturing. Method for producing coke for use.