JPS62197B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for rolling granulating coke powder, which is generated in large quantities during, for example, the production of metallurgical coke, the sizing process, and the transportation process. [Prior art] In the coke manufacturing process, many coke breezes are used when extinguishing red-hot coke discharged from a coke oven, or when crushing lump coke to size it to a size suitable for use in a blast furnace. occurs. In addition, the exhaust gas from the top of the blast furnace also contains a large amount of coke breeze, which is called gas ash and is collected for reuse. One of the ways to use the generated coke powder is to
A method for granulating coke powder that can be used as a fuel for sintering powdered iron ore is disclosed in JP-A-54-127902 and JP-A-54-129003. [Problems to be solved by the invention] The properties required for granulated coke as a fuel for sintering powdered iron ore include a particle size that can maintain air permeability during sintering, and a requirement for charging into a sintering machine. It is required to have appropriate strength so that it does not turn into powder during the process. On the other hand, granulation is also carried out to use iron-containing dust such as steelmaking dust collected in the steelmaking process as return ore and use it as a sintering raw material, but the surface condition of the coke powder is a collection of sharp protrusions. It also has many pores, and its properties and shape are completely different from those of return ore, and it is extremely difficult to granulate it efficiently by applying the granulation method of these iron-containing dusts as is. . An object of the present invention is to provide a method for efficiently granulating coke powder in order to obtain granulated coke that can satisfy the above conditions, particularly as a fuel for sintering powdered iron ore. [Means for Solving the Problems] The present invention provides that when granulating such coke powder,
This was completed based on the knowledge that granulation performance is significantly inhibited when a large amount of intermediate particles with particle diameters in the range of 0.5 to 0.15 mm are present. Regarding the factors that inhibit the granulation of intermediate grains when granulated using a drum-type or disk-type rolling granulator,
Although it has not yet been theoretically elucidated, it is thought that this intermediate grain portion is difficult to become a nucleus for the formation of its own grains, and is also difficult to act as attached particles. Therefore, in order to obtain efficient granulation, it is necessary to remove intermediate grains that inhibit granulation properties by sieving or pulverizing them to keep the content below a certain level.
In the present invention, the intermediate grain portion in the range of 0.5 to 0.15 mm is adjusted to be 40% by weight or less, preferably 30% by weight or less in the raw coke powder. In other words, the present invention adjusts the particle size distribution to increase the particle size.
Raw material powder with a particle size of 1 mm or less, with 40% by weight or less of intermediate particles of 0.5 to 0.15 mm, 20 to 50 weight% of fine particles of less than 0.15 mm, and less than 80 weight% of coarse particles of more than 0.5 mm and 1 mm or less. Prepare coke, 100% of the raw coke powder
By blending 3 to 10 parts by weight of cement to the parts by weight, further adding and adjusting moisture so that the final moisture content is 12 to 20% by weight, and then rolling granulation.
Particularly, granulated coke powder can be obtained which can be suitably used as a fuel for sintering powdered iron ore. The coke powder used in the present invention is, for example, coke powder recovered from a fire extinguishing tower sedimentation basin in coke manufacturing, or coke powder recovered from exhaust gas in dry extinguishing, and has a particle size as illustrated in Table 1. This is fine powder coke with a particle size of 1 mm or less and a moisture content of 1% by weight or less or in a dry state.

〔Example〕

For 100 parts by weight of raw coke powder collected from the sedimentation tank attached to the wet fire extinguishing tower of a coke manufacturing equipment and adjusted to the particle size composition shown in Table 2,
6 parts by weight of ordinary Portland cement was blended, and a total of 40 kg was stirred and mixed using a kneader to uniformly disperse it in the raw coke powder.
Using a pan with a pan angle of 0.12 m and a pan inclination angle of 55 degrees and a rotation speed of 12 rpm, the blended raw materials were continuously supplied in a fixed amount for 25 minutes, during which time water was continuously supplied, and finally The moisture content was adjusted to 16% by weight and granulated. As a result, granulated coke with a particle size of 0.5 mm or more, which can be used as a sintering fuel, was obtained. Nos. 1 to 4 in Table 2 indicate examples of the present invention,
Nos. 5 to 8 show comparative examples. In the evaluation column of the same table, the granulation efficiency was defined as the proportion of fine powder with a particle size of less than 0.5 mm that inhibits air permeability as a sintering fuel in the particle size distribution of raw coke powder. Specifically, based on the reduction ratio of the proportion of fine particles of 0.5 mm or less in the raw material coke particle size in the same table after granulation, 70% by weight or more is considered good (◎), and 60% by weight or more is 70% by weight. If it was less than % by weight, it was rated as slightly poor (△), and if it was less than that, it was rated as poor (x). Referring to the same table, it can be seen that by the granulation method of the present invention, most of the fine powder in the raw coke powder could be used as fuel for granulation and sintering. Moreover, the granulated coke obtained by the present invention had no problem of pulverization and had sufficient strength to withstand as a sintering fuel.

〔Effect of the invention〕

According to the present invention, coke powder can be efficiently rolled and granulated, and the resulting granules have air permeability and strength suitable as a fuel for sintering ores.

Claims (1)

[Claims] 1 Adjust the particle size distribution so that intermediate particles with a particle size of 0.5 to 0.15 mm are 40% by weight or less, fine particles of less than 0.15 mm are 20 to 50% by weight, and coarse particles with a particle size of more than 0.5 mm and 1 mm or less are less than 80% by weight. Prepare raw coke powder with a particle size of 1 mm or less, add 3 to 10 parts by weight of cement to 100 parts by weight of the raw coke powder, and finally remove moisture.
A method for granulating coke powder, which comprises adding and adjusting water content to 12 to 20% by weight and then granulating it by rolling.