JPH0558477B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field This invention is directed to coke powder generated in large amounts during the coke manufacturing process, during dry and wet extinguishing of red-hot coke discharged from a coke oven, and during particle size adjustment by crusher crushing to use lump coke in a blast furnace. This invention relates to a method for molding coke powder for reusing coke as highly reactive coke. Prior Art In the coke manufacturing process, a large amount of coke is generated during dry and wet extinguishing of red-hot coke discharged from a coke oven, and during particle size adjustment by crusher crushing to use lump coke in a blast furnace. The powder percentage reaches 14-15%. Therefore, efforts are being made to reuse the generated coke powder. A conventional recycling method generally involves adding a binder to coke powder and granulating it. For example, there is a method in which cement is blended with coke powder adjusted to a certain particle size composition, the moisture content is adjusted, and then granulated by rolling (Japanese Patent Publication No. 62-197), activated sludge and a caking agent are added to coke powder. A method of adding cement and molding with a granulator (Japanese Patent Application Laid-Open No. 56-36593), in which cement is mixed with coke powder and the raw material whose moisture content is adjusted is stirred to form a combined granulated core, and this combined granulated core and coke powder are mixed. There is a method of rolling granulation (Japanese Patent Publication No. 59-3511), and a method of adjusting the humidity of coke powder and adding cement to the tempered coke powder and granulating it by rolling (Japanese Patent Publication No. 54-129003). However, in the conventional method, several days are required for the pellets to develop strength after granulation of coke powder. The pellets produced are all used as fuel for sintering, and have low cold strength and low JIS reactivity. Problems to be Solved by the Invention As mentioned above, the conventional reuse of generated coke powder is mainly to produce pellets used as sintering fuel, and it is unsuitable as metallurgical coke due to its low JIS reactivity. It was hot. This invention eliminates the drawbacks seen in conventional methods,
It is an object of the present invention to provide a method for molding coke powder having high reactivity that can be used for high value-added applications, such as coke for electric furnaces. Means for Solving the Problems In order to achieve the above object, the method for molding coke powder of the present invention includes dry and wet extinguishing of red hot coke discharged from a coke oven and lump coke in a blast furnace during the coke manufacturing process. The raw material is coke powder, which is produced in large quantities during the particle size adjustment by crusher crushing for use in the industry.After adjusting the moisture content of this to approximately 10%, 5 to 6% by weight of quicklime is mixed and kneaded as a hardening agent. Mix 12 to 13% by weight of blackstrap molasses as a binder and press-mold. In this invention, if the amount of quicklime added to powdered coke, which is the raw material for molding, is less than 4% by weight, the addition effect as a hardening agent will not be obtained sufficiently, and if it exceeds 7% by weight, the volume due to the reaction of undigested quicklime after pressure molding. The amount was set at 4 to 7% by weight because expansion is inhibited by the escape of steam generated inside due to temperature rise, and as time passes, many fine cracks occur on the surface and inside, leading to a decrease in the strength of the produced coke. Further, the quicklime to be added preferably contains 60% by weight or more of CaO. Ca(OH) ₂ and CaCO ₃ reduce moldability and the strength of the formed molded coke, and do not work effectively as hardening agents. If the amount of blackstrap molasses added is less than 10% by weight, the added effect as a binding agent will not be sufficiently obtained, and both the crushing strength and trommel strength of the molded coke will be low. Also, 14% by weight
Since no improvement in the addition effect was observed even if the amount was added in excess of 10% to 14% by weight. The procedure in this invention is to add blackstrap molasses as a caking agent after adding and kneading quicklime to powder coke as a raw material for molding. This is because it becomes difficult and causes segregation, resulting in a decrease in the strength of the molded coke. It is assumed that this is because the addition of quicklime as a hardening agent causes an exothermic reaction of the water contained in the molding raw material coke powder and blackstrap molasses, and a highly viscous compound is produced by the evaporation of the water and the reaction with the blackstrap molasses during kneading. Ru. In addition, by using blackstrap molasses, which is commonly used as a binder, and quicklime as a hardening agent, JIS
The reason for the significant improvement in reactivity is presumed to be that CaO, which acts as a catalyst during the reaction, remains in the coke as ash due to the addition of quicklime, increasing the reaction rate. Function By blending quicklime as a hardening agent and blackstrap molasses as a caking agent into coke powder and pressurizing it,
It can increase the crushing strength and trommel strength of molded coke, and also brings about good results in JIS reactivity. Examples Example 1 CDQ coke powder collected by the primary dust remover and cyclone of the dry fire extinguishing equipment whose particle size distribution is shown in Table 1 is used as a molding raw material (particle size distribution is between coke powder A and B). The moisture content of the coke powder, which is the raw material for molding, was adjusted to about 10%, and quicklime, whose properties are shown in Table 2, was added in a range of 3 to 7% by weight, and the mixture was placed in a mixer (Mix Muller) and kneaded for 4 minutes. Add 12% by weight of blackstrap molasses whose properties are shown in Table 3, knead for another 10 minutes, and use a double roll forming machine at a peripheral speed of 0.33.
Molded coke was produced by pressurizing at m/sec.

【table】

【table】

[Table] The molding retention, crushing strength and trommel strength of the obtained molded coke after 2 hours were measured.
The results are shown in FIGS. 1 and 2. As shown in FIGS. 1 and 2, when the amount of quicklime added is less than 4%, both the crushing strength and trommel strength of the formed coke and the molding yield rapidly decrease. Normally, when manufacturing coke for electric furnaces, there are no required standards for crushing strength and trommel strength, but coke for blast furnaces has a crushing strength of 30 kg/
It is desirable to manufacture a material with a strength close to the required level of P or higher and trommel strength of 90% or higher. Therefore, it is desirable that the amount of quicklime added be 4% by weight or more. Example 2 The moisture content of the molding raw coke powder shown in Table 1 was adjusted to about 10%, 5% by weight of quicklime shown in Table 2 was added, and the mixture was kneaded for 4 minutes using a kneading machine in the same manner as in Example 1. Afterwards, add 8 to 14% by weight of blackstrap molasses shown in Table 3.
The coke was added in a range of 10%, kneaded for further 10 minutes, and then pressure molded under the same conditions as in Example 1 to produce molded coke. The crushing strength of the obtained molded coke after 2 hours and 6 hours, the trommel strength after 2 hours, and the molding yield were measured. The results are shown in FIGS. 3 and 4. As shown in FIGS. 3 and 4, when the amount of molasses added is less than 10% by weight, the crushing strength, trommel strength, and molding yield decrease rapidly, and the strength is close to the required level of blast furnace coke. cannot be held. Therefore, the addition of blackstrap molasses is preferably 10% by weight or more. Example 3 The moisture content of the molding material coke powder used in Example 1 was adjusted to about 10%, 5-6% by weight of quicklime was added, and after kneading for 3 minutes, blackstrap molasses was mixed with 12-13% by weight.
was added, kneaded for an additional 10 minutes, and molded under pressure to produce four types of molded coke. Then, the JIS reactivity of the obtained molded coke was investigated. The results are shown in Table 4. For comparison, the table also shows the JIS reactivity of commercially available coke for use in electric furnaces.

[Table] According to the above table, the molded coke according to the present invention
It can be seen that the JIS reactivity is extremely high. Effects of the Invention As described above, the present invention provides a reduction in coke for blast furnaces.
Using powdered coke generated from JIS reactive coke as a molding raw material, coke with high cold strength and high JIS reactivity required as coke for electric furnaces is produced by jointly kneading quicklime and waste molasses and molding under pressure. It can be easily manufactured.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between quicklime addition rate and crushing strength of molded coke in the practice of this invention, Figure 2 is a graph showing the relationship between quicklime addition rate, trommel strength, and molding yield, and Figure 3 is a graph showing the relationship between quicklime addition rate, trommel strength, and molding yield. 4 is a graph showing the relationship between the amount of molasses added and the crushing strength of molded coke in the practice of this invention, and FIG. 4 is a graph showing the relationship between molasses, trommel strength, and molding yield.

Claims (1)

[Claims] 1. In the coke manufacturing process, coke powder is produced in large quantities during dry and wet extinguishing of red-hot coke discharged from coke ovens, and during particle size adjustment by crusher crushing for use in blast furnaces. After adjusting the amount to approximately 10%, 5 to 6% by weight of quicklime is mixed and kneaded as a hardening agent, and 12 to 13% by weight of blackstrap molasses is further blended as a binding agent and pressure molded. A method for molding coke powder with properties.