JPH07122104B2 - Sintering raw material manufacturing method from ironmaking dust - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a sintering raw material from iron-making dust, and in particular, the present inventor disclosed in Japanese Patent Application No. 62-260426 (JP-A-1-104723). Related to improvements related to the same law.

[Conventional technology]

In an iron mill, dust generated from a blast furnace, a converter, etc. is recovered and used as a sintering raw material, and is charged into the blast furnace again through the sintering furnace. A conventional method for producing a sintering raw material from iron-making dust will be described with reference to FIG. The wet dust 2 generated in the blast furnace and the converter and wet-collected enters the sychner 4 in the form of a slurry, is concentrated, is supplied to the filter 8 by the press-fitting pump 6, is dehydrated, and is then supplied to the mixer 12 by the conveyor 10, while Dry dust 14 collected by the dust collector is tank truck 16
It is carried in the tank 18 and put in the tank 18, and the mixer 20 is installed on the conveyor 20.
Is supplied to. After being mixed in the mixer 12, the conveyor
It is supplied to a rotary dryer 24 at 22 and is dried and granulated and then conveyed at a conveyor 26 as a sintering raw material.

Since the amounts of the wet dust 2 having a water content of 22% or more and the dry dust 14 having a water content of 0% change depending on the production situation of each factory, the inlet water content of the charge of the rotary dryer 24 changes. The dry dust 14 may also be used for other purposes. Heretofore, no particular adjustment has been made to the change in water content due to the change in the amounts of the wet dust 2 and the dry dust 14. For this reason, when the amount of dry dust 14 decreases and the water content becomes excessive, the sintering raw material adheres and grows near the inlet of the rotary dryer 24, which may eventually cause clogging and make the operation impossible, and the proportion of lumps increases. However, it was sometimes unsuitable as a sintering raw material. On the other hand, if the amount of dry dust 14 is too large, the water content is insufficient and the rotary dryer 24 is unlikely to form particles, and even if particles are formed, the strength is weak and unsuitable as a sintering material. Therefore, conventionally, the water content fluctuates depending on the amounts of the wet dust 2 and the dry dust 14, making it difficult to manufacture a stable sintering raw material.

In order to solve the above-mentioned problems of the prior art, the present inventors have
Previously, Japanese Patent Application No. 62-260426 disclosed the following method for producing a sintering raw material from iron-making dust. That is, in the method for producing a sintering raw material in which wet dust and dry dust generated in an iron mill are mixed by a mixer and dried and granulated by a rotary dryer, the water content of the sintering raw material in the mixer is 16
Adjust the charging amount of wet dust and dry dust so that it becomes ~ 20%, and if the amount of dry dust required for adjustment is insufficient, part of the sintering raw material after the dry granulation is returned to the mixer. Step, controlling the combustion of the burner of the rotary dryer so that the water content of the sintering raw material after dry granulation by the rotary dryer becomes 10 to 14%, and the sintering raw material after dry granulation in the rotary dryer. Sieving and crushing the sintering raw material remaining on the sieve and returning it to the mixer, and a method for producing a sintering raw material from iron-making dust.

The outline of the present invention will be described with reference to FIG. The present invention has the following three features, and most of the drawbacks of the above-mentioned conventional techniques can be solved and a temporary effect can be obtained. The three features are as follows.

First, the moisture meter is installed on the discharge side conveyor 22 of the mixer 12.
28 is installed, the amount of wet dust 2 and dry dust 14 is adjusted so that the water content in the sintering raw material is 16 to 20%, and when the amount of dry dust 14 required for adjustment is insufficient, the carp bearer 26
A part of the dried and granulated sintering raw material that has been transported in (1) is separated by a damper 28 and returned to the mixer 12 by conveyors 30 and 32 to adjust the water content. The remaining sintering raw material separated by the damper 28 is conveyed by the conveyor 34. If the water content in the sintering raw material is less than 16%, the granulation in the rotary dryer 24 will be insufficient, making it unsuitable as a sintering raw material.
If it exceeds%, it will adhere to the rotary dryer 24 and cause clogging.
Limited to the range of 16-20%.

Next, the second point is that the moisture meter 36 provided on the conveyor 26
The moisture content of the burner 38 of the rotary dryer 24 is controlled so that the moisture content of the sintering raw material after the dry granulation by the rotary dryer 24 becomes 10 to 14%. If the water content of the sintering raw material after dry granulation is less than 10%, the granulation will be insufficient and part of it will become fine powder, which is not suitable as a sintering raw material, while if it exceeds 14%, it will adhere to various equipment and cause clogging. Because of this, the water content was limited to the range of 10-14%.

Finally, the third point is that the dried and granulated sintering raw material conveyed by the conveyor 34 is sieved by a sieve 40 of about 7 mm, and the sieve is crushed by the crusher 42 and returned to the mixer 12 by the conveyor 32. To be done. On the other hand, the size under the sieve has an optimum particle size of about 0.5 to 7 mm as a sintering raw material, and is conveyed to the sintering furnace by the conveyor 44.

As described above, the present inventors have limited the amount of water before charging and discharging the rotary dryer according to the prior art, and returned a part of the sintering raw material after dry granulation to the mixer to adjust the amount of water. Moreover, the following effects can be obtained by further selecting the sintering raw material after dry granulation according to the particle size.

(A) A sintering raw material having an appropriate particle size distribution could be manufactured during the sintering operation.

(B) Stable operation was possible by preventing the formation of deposits in the rotary dryer.

As a result, the effect of remarkably improvement as compared with the conventional method shown in FIG. 5 can be contained.

[Problems to be solved by the invention]

Although the above-mentioned prior art was able to achieve a remarkable effect as compared with the conventional method, it was found that the following problems still exist.

(A) According to the conventional rotary dryer, the product particle size distribution on the outlet side is wide, and there is a problem in drying the iron-containing dust generated in the iron mill and using it as a raw material for sintering.

(B) Since the ratio of grain size −2 mm is increasing, if this is directly charged into the sintering machine, the air permeability is deteriorated.

The object of the present invention is to solve the above-mentioned problems in the practice of the invention disclosed in Japanese Patent Application No. 62-260426 and to effectively produce a sintering raw material having an optimum particle size distribution from iron-making dust. It is intended to provide a method.

[Means for solving problems]

 The gist of the present invention is as follows.

That is, “(1) a step of controlling the water content of the sintering raw material in the mixer to 16 to 20% by adjusting the charging amounts of the wet dust and the dry dust generated in the steel mill when mixing them in the mixer. In the method for producing a sintering raw material from iron-making dust comprising, a lifter and a chain for crushing cake-like wet dust in the rotary dryer have an area of 1/4 to 1/3 with respect to the entire length of the front part of the rotary dryer. A method for producing a sintering raw material from iron-making dust, which comprises applying a dam to a slag and extending a residence time of the dust in a granulation working region by installing a dam near the outlet of the rotary dryer.

(2) The method for producing a sintering raw material from iron-making dust as described in (1) above, wherein the particle size distribution of the product on the delivery side of the rotary dryer is approximately 95% for 10 to 2 mm and 5% for −2 mm in weight ratio. The dry dust generated in the steel mill has a water content of O, but the wet dust has a water content of about 24%. 20% and supply this to the rotary dryer 24. Cake-like wet dust remains in the first half of the rotary dryer, and since the dust is in a wet state containing 16 to 20% of water, dust particles become large and coarse particles are easily formed.

FIG. 2 is a schematic cross-sectional view showing an embodiment of the manufacturing process according to the present invention. The process is the same as that shown in FIG. 4 of JP-A-1-104723, but the device in the rotary dryer 24 is remarkably improved. Was done.

That is, according to the present invention, the coarse dust particles 2 are unraveled by providing the lifter 50 or the chain 52 which projects from the front half lining in the rotary dryer 24 and uses L-shaped steel or the like as shown in FIGS. 1 (A) and 1 (B), respectively. Crush.

In this case, in the lifter 50, crushing is performed by scraping and dropping action of the raw material accompanying the rotation of the rotary dryer 24, and in chain 52, crushing is performed by the stirring action of the raw material by the rocking motion associated with the rotation of the rotary dryer 24. Then, the dust particles in the rotary dryer 24 are atomized. Lifter 50 or chain 52 for this refinement
The front part of the
1/4 to 1/3 is preferable, crushing effect is insufficient if installed less than 1/4, raw material is excessively pulverized if installed in an area exceeding 1/3, and rear granulation is insufficient And the fine powder in the product increases. Therefore, it is preferable to install the rotary dryer 24 in the front part and in the area of 1/4 to 1/3 of the entire length.

As described above, the coarse particles 2 in the raw material dust supplied to the rotary dryer 24 are crushed in the first half, and in the subsequent second half, the raw material is prevented from being pulverized and granulated.

In the present invention, in order to improve the granulating action, a dam 54 is provided near the outlet of the rotary dryer 24, and a feature is that the dust is being granulated and the retention time in the granulation working region is lengthened. is there.

As a result, only the dust that has been granulated will preferentially get over the dam 54 and be discharged from the rotary dryer 24, and the amount of dust that is discharged as -2 mm powder will be extremely small, and the classification effect will be combined. It came to be demonstrated.

As described above, since the coarse dust is crushed in the first half of the granulated dust discharged from the rotary dryer 24, it becomes dust particles grown only in the latter half of the granulation, and the coarse particles are greatly reduced. To be done.

In addition, since the moisture content of the dried and granulated sintering raw material discharged from the rotary dryer 24 is adjusted to 10 to 14%, the moisture is further conveyed by the conveyor 34 and sieved by the sieve 40 of about 7 mm, so +10 mm, etc. Although the sintering raw material on the sieve is crushed to a predetermined particle size of the crusher 42, the sintering raw material on the coarse sieve is greatly reduced as described above, so that the amount of pulverization due to the crushing can be reduced to −2 m.
Generation of m powder is extremely reduced, and it can be sent to the sintering machine together with the crushed sieve.

FIG. 3 is a comparison diagram of the particle size distributions of the sintering raw material manufactured by the conventional method shown in FIG. 4 and the method of the present invention. In the present invention, the particle size is adjusted in the rotary dryer 24, and By installing the dam 54 at the discharge end of the rotary dryer, the residence time in the granulation working area is extended, and the effect of suppressing the generation of coarse particles and at the same time preventing the generation of fine particles is distributed as shown in Fig. 3. It is also clear from the comparison of the figures.

〔The invention's effect〕

In order to solve the problems remaining in the prior art disclosed in Japanese Patent Application No. 62-260425 (Japanese Patent Application Laid-Open No. 1-104723), the present invention scrapes the raw material inside the rotary dryer 24 and wets the cake. The use of the lifter 50 and the chain 52 for dust crushing is limited to the first half only and not used in the second half, and the dam 54 is provided near the outlet of the rotary dryer 24 for granulation. Since the residence time of the dust in the granulation working region was extended, the following effects could be achieved.

(B) The mixing rate of -2 mm, which was about 30% by weight, which was conventionally mixed, was significantly reduced to about 5%.

(B) The particle size distribution of the sintered raw material is 2 to 3 as shown in FIG.
The sintering raw material with the optimum grain size of 10 mm was 95%, and the operating results of the sintering furnace were significantly improved.

[Brief description of drawings]

1 (A) and 1 (B) are partial perspective views showing a lifter and a chain provided in the lining of the first half of the rotary dryer according to the present invention, and FIG. 2 is a sintering raw material production from iron-making dust according to the present invention. FIG. 3 is a schematic cross-sectional view showing the apparatus of the process, FIG. 3 is a diagram comparing the particle size distributions of the sintering raw materials produced by the method of the present invention and the conventional method, FIG. 4, and FIG.
Each of the figures is a schematic cross-sectional view showing an apparatus for manufacturing a sintering raw material from iron-making dust by a conventional method, and FIG.
FIG. 5 is a process diagram disclosed in 4723, and FIG. 5 is a process diagram showing a conventional method prior to JP-A-1-104723. 2 ... Wet dust, 4 ... Shuckner 8 ... Filter, 12 ... Mixer 10, 20, 22, 26, 30, 32, 34, 44 ... Conveyor 18 ... Tank, 24 ... Rotary dryer 28 ... Damper, 38 …… Burner 40 …… Sieve, 42 …… Crusher 50 …… Lifter, 52 …… Chain 54 …… Dam

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobutake Kasashima 1-chome (no address) Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture Kawatetsu Mining Co., Ltd. Mizushima Plant (56) Reference JP-A-1-104723 (JP, A) ) JP-B-45-10601 (JP, B1)

Claims (2)

[Claims] 1. A step of controlling the water content of a sintering raw material in the mixer to 16 to 20% by adjusting the charging amounts of the wet dust and the dry dust generated in an iron mill when mixing them in a mixer. When dry granulating the mixed dust by the mixer with a rotary dryer, the combustion of the burner of the rotary dryer is adjusted to control the water content of the sintering raw material after dry granulation to 10 to 14%. In the method for producing a sintering raw material from iron-made dust, the lifter and the chain for crushing the cake-like wet dust in the rotary dryer have a total length of the front part of the rotary dryer.
Sintering from iron-making dust, characterized in that it is applied only to the 1/4 to 1/3 region, and a dam is installed near the outlet of the rotary dryer to extend the residence time of the dust in the granulation working region. Raw material manufacturing method. 2. The sintering raw material from iron-making dust according to claim 1, wherein the particle size distribution of the product on the outlet side of the rotary dryer is approximately 95% for 10 to 2 mm and 5% for −2 mm in weight ratio. Production method.