JP4317316B2 - Pretreatment method of sintering raw materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for pre-processing a sintered raw material in which a binder is added to iron-containing powder and granulated into pseudo grains.
[0002]
[Prior art]
Conventionally, sintering raw materials are iron-containing powders such as iron-containing dust, sludge, iron ore powder, etc. Add a binder made of quick lime powder or slaked lime and coke powder as fuel, and granulators such as rotary kiln type or bread type Is processed into pseudo particles.
The pseudo particles are charged into an endlessly connected pallet, and coke attached to the pseudo particles is ignited in an ignition furnace to start combustion. This combustion moves from the upper layer to the lower layer, and all layers are sintered to produce a sintered ore.
However, in this granulation method, as shown in FIG. 5, quick lime powder 53, which is an example of a binder stored in the storage hopper 52, is cut out from the feeder 54 on the iron-containing powder 50 being conveyed by the belt conveyor 51. Send to granulator.
And as shown in FIG. 6, the remaining iron-containing powder 50 adheres to the circumference | surroundings of the nuclear ore 55 which consists of the iron-containing powder 50 of a comparatively big particle | grain using the adhesiveness of the quicklime powder 53, as shown in FIG. Aggregated layer 56 is formed to become pseudo particles 57.
However, the unreacted quicklime powder 53 exists in the agglomerated layer 56 formed by adhering to the periphery of the nuclear ore 55, and the fine particles of the iron-containing powder 50 cannot be sufficiently adhered to form the agglomerated layer 56. .
As a result, the ungranulated iron-containing powder 50 remains, resulting in a decrease in granulation yield, an increase in cost due to the increased use of quick lime powder 53, a decrease in strength of the pseudo particles 57, and the like.
As a countermeasure, as described in JP-A-4-254533, quick lime powder is preliminarily added with water to form a slurry and poured into a belt conveyor, and iron-containing powder is cut out and laminated on the slurry. When forming pseudo | simulated particles by conveying and supplying to a granulating apparatus and manufacturing pseudo | simulated particles, formation of the nucleus from a fine grain is accelerated | stimulated and granulation is performed.
Furthermore, as described in Japanese Examined Patent Publication No. 59-17171, water is added to the quicklime powder added on the iron-containing powder laminated on the belt conveyor, and the quicklime powder is wet-treated and hydrated in advance. By promoting the reaction, the tackiness is improved to improve the granulation efficiency.
[0003]
[Problems to be solved by the invention]
However, in the method described in JP-A-4-254533, the iron-containing powder is cut out and laminated on a highly sticky slurry containing a large amount of slaked lime (Ca (OH) ₂ ) generated by a hydration reaction. The slaked lime in the slurry cannot be uniformly dispersed in the iron-containing powder, and the density of slaked lime is generated in the pseudo particles during the granulation process.
As a result, the granulation yield decreases due to the non-granulated iron-containing powder, resulting in an increase in cost and a decrease in the strength of the pseudo particles due to an increase in the amount of quicklime powder used.
Furthermore, in the method described in Japanese Examined Patent Publication No. 59-17171, quick lime powder is laminated on iron-containing powder, and then the quick lime is sprinkled to make a hydration reaction to obtain slaked lime, which becomes a binder. Slaked lime is solidified on the iron-containing powder or slaked lime is likely to condense, and it is difficult to sufficiently disperse it in the iron-containing powder.
Moreover, since the dispersibility is poor when the pseudo particles are formed by the granulating apparatus, there is a condensed portion of slaked lime in the aggregated layer formed around the pseudo particles, which is described in JP-A-4-254533. Similar to the method, the granulation yield is reduced by the ungranulated iron-containing powder. In addition, there is a problem that an increase in granulation cost due to an increase in the amount of quicklime used and a decrease in the strength of pseudo particles occur.
[0004]
The present invention has been made in view of such circumstances, to improve the granulation yield by suppressing the ungranulated iron-containing powder, improve the granulation efficiency by reducing the amount of binder such as quick lime powder, granulation It aims at providing the pre-processing method of the sintering raw material which can reduce the cost and improve the quality of pseudo particles.
[0005]
[Means for Solving the Problems]
Preprocessing method for sintering the raw material of the present invention along the object, in the pre-processing method of the sintering raw material to granulate the ferrous powder by adding a binder to the iron-containing powder, with lime powder to the binder, the ferrous Within 1 minute after adding water to the powder, the quicklime powder is mixed with gas and sprayed onto the iron-containing powder so that the solid-gas ratio is 100 or less, and the quicklime powder is dispersed to the iron-containing powder. Added.
In addition, dispersion | distribution means giving the external force which scatters a falling flow, or mixing and adding a binder to gas or water previously, when dropping and adding a binder from a belt conveyor.
By this method, the binder can be uniformly distributed in the iron-containing powder, and the iron-containing powder can be efficiently attached around the core ore by using the adhesive action of the binder, thereby forming a good aggregated layer. The granulation efficiency can be improved.
[0006]
Here, Ru with lime powder to the binder.
Thereby, favorable dispersibility and adhesiveness can be expressed, granulation of iron-containing powder can be further promoted, and quality such as strength of pseudo particles can be enhanced.
[0007]
Furthermore, Ru spraying a mixture of the binder into a gas.
Since the binder is dispersed by the blowing force of the gas, it is possible to prevent the binder from condensing by adsorbing moisture contained in the iron-containing powder, and can be effectively used for making the iron-containing powder pseudo particles.
[0008]
Also, you a solid-gas ratio of the binder to 100 below.
Since the solid-gas ratio of the binder when added to the iron-containing powder (the ratio of the weight of the solid to the weight of the gas) is within a predetermined range, the dispersibility of the binder is greatly improved, and the moisture content of the iron-containing powder and the like Aggregation due to the reaction of the binder can be stably suppressed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
The inventors of the present invention have paid attention to this phenomenon, paying attention to the fact that, when producing pseudo particles by granulating iron-containing powder, sufficient pseudo particles may not be achieved even if the amount of binder added is increased. I did research.
And when we investigated the pseudo particles with poor granulation properties, some of the iron-containing powder adhered to the periphery of the nuclear ore was found to be coagulated, and it did not function as a binder sufficiently. The cause of this is that the binder adsorbs moisture etc. of the iron-containing powder and causes the setting, and no matter how the kneading is strengthened by the granulator, the setting of the binder in the iron-containing powder cannot be improved. It was found that the grain efficiency was reduced.
Thus, it has been found that by adding the binder to the iron-containing powder by dispersing the binder, the coagulation of the binder can be suppressed and the iron-containing powder can be effectively adhered, and the present invention has been completed.
Here, FIG. 1 is an overall view of a granulating apparatus applied to a sintering raw material pretreatment method according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA of the granulating apparatus. 3 is a graph showing the relationship between the amount of air and the solid-gas ratio, and FIG. 4 is a graph showing the relationship between the quicklime reaction rate and the production amount of sintered ore.
As shown in FIG.1 and FIG.2, the granulation apparatus 10 used for the pre-processing method of the sintering raw material which concerns on one embodiment of this invention is a cylindrical rotary kiln 12, iron ore powder, sludge, dust collection dust. An iron-containing powder 11 made of, for example, a chute 13 for cutting the iron-containing powder 11 into the rotary kiln 12, and a quick-lime powder supply pipe 15 that presses and sprays quick-lime powder 14, which is an example of a binder, together with air to the iron-containing powder 11 that rolls inside the rotary kiln 12. And a belt conveyor 16 that conveys pseudo particles formed by granulating the iron-containing powder 11.
[0010]
Next, the pretreatment method of the sintering raw material which concerns on this Embodiment using the granulator 10 is demonstrated.
The iron-containing powder 11 is cut from the chute 13 into the rotary kiln 12 at 10 to 15 tons / min, the rotary kiln 12 is rotated at 3 to 9 times / min, and water is added to the iron-containing powder 11 of the rotary kiln 12 at 0.1 to 2% by weight. Then, the iron-containing powder 11 is moved in the direction of the arrow (FIG. 1) while rolling the iron-containing powder 11.
By adding water within 1.0 to 2.0 minutes from the start of rolling, the iron-containing powder 11 having a relatively large size becomes a nuclear ore, and the fine particles of the iron-containing powder 11 adhere to the surroundings and become pseudo particles. Begin to form.
Simultaneously with the addition of water or within 1.0 minute from the addition of water, the quicklime powder 14 mixed with air is conveyed from the quicklime powder supply pipe 15 and sprayed onto the surface of the iron-containing powder 11.
The quicklime powder 14 is continuously sprayed on the surface of the iron-containing powder 11 that is rolling.
Here, if water is added after 2 minutes or more from the start of rolling, or if quick lime powder is added after 1 minute or more from the addition of water, the granulation time in the rotary kiln is insufficient and sufficient. Granulation becomes difficult.
And since the iron-containing powder 11 is rolling, the quick lime powder 14 can always be sprinkled on the surface of the new iron-containing powder 11, and the synergistic action of spraying the quick-lime powder 14 mixed with air and rolling of the iron-containing powder 11 is possible. Thereby, the quicklime powder 14 can be mixed in the iron-containing powder 11 very uniformly.
The quick lime powder 14 mixed with the iron-containing powder 11 generates slaked lime (Ca (OH) ₂ ) with good adhesiveness by the reaction of the water in the iron-containing powder 11 or the added water with the following formula.
CaO + H ₂ O → Ca (OH) ₂
As shown in FIG. 2, the slaked lime is formed by causing the iron-containing powder 11 to roll by the rotation of the rotary kiln 12, thereby sticking the fine iron-containing powder 11 around the above-mentioned nuclear ore, An agglomerated layer can be formed, and excellent quality pseudo-particles with less ungranulated powder can be formed.
[0011]
As shown in FIG. 3, the solid-gas ratio when quicklime powder is mixed with air rapidly increases when the amount of quicklime powder transported is 5 to 20 t / hr and the amount of air used for transport is less than 200 Nm ^3. .
If the solid-gas ratio exceeds 100, pulsation and the like occur during transportation, and the transport amount of quick lime powder fluctuates greatly. Remains.
As a result, since the sticking action of the remaining quicklime powder is poor, the fine particles of the iron-containing powder cannot be stuck around the nuclear ore, the granulation efficiency is greatly deteriorated, and the strength of the pseudo particles is also reduced.
Therefore, the amount of quick lime powder 14 added or the amount of air for conveyance is adjusted, and the amount of carrier gas and the amount of solid to be sprayed are adjusted so that the solid-gas ratio becomes 100 or less.
Here, the solid-gas ratio is a value obtained by dividing the weight of the added quicklime powder by the carrier air weight.
[0012]
In addition, as a method for easily grasping the quality of the distribution of quicklime powder and the quality of granulation efficiency, the pseudo particles are analyzed, and the amount of unreacted quicklime powder and the amount of slaked lime generated by reacting with moisture are calculated. It can be determined by measuring.
That is, the amount of unreacted quicklime powder contained in the pseudo particles and the amount of slaked lime generated by reacting with moisture are respectively measured, the ratio of slaked lime to the amount of added quicklime powder is determined, and this ratio (quicklime reaction rate) is set to 60 to By keeping it high at 80%, the granulation efficiency can be improved, and the occurrence of ungranulated powder can also be prevented.
Since the pseudo particles produced in this way have a uniform distribution of slaked lime due to the hydration reaction of quicklime powder, the quality of the granulated pseudo particles is good, and this is used as a sintering machine. The sinter is produced by supplying, and the quality of the produced sinter can be improved.
[0013]
【Example】
Next, the Example of the pre-processing method of the sintering raw material which concerns on this invention is described.
Cut iron-containing powder mixed with iron ore powder and dust-collecting dust into a rotary kiln from a 13-ton / min chute, rotate the rotary kiln at a speed of 6.5 times / min, and add 1.0% by weight of water to the iron-containing powder. did.
And when 1 minute has passed since water was added, granulation is carried out by spraying on the iron-containing powder rolling by adjusting the solid-gas ratio of air and quicklime powder to 10 from the quicklime powder supply pipe. Then, the quicklime reaction rate and the productivity of sintered ore were investigated.
As a result, as shown in FIG. 4, in the present invention in which quick-lime powder is sprayed with a solid-gas ratio of 10, the quick-lime reaction rate can be improved to a range of 60 to 80%, and sintering is performed using granulated pseudo particles. As a result, the production of sintered ore was significantly improved to 630 to 640 t / hr.
On the other hand, in the case of conventional addition in which quick lime powder is simply cut out from the feeder without being dispersed on the iron-containing powder being conveyed by the belt conveyor, the dispersibility of the quick lime powder is poor and is uniformly distributed in the iron-containing powder. Therefore, as a result of investigating the cross section of the pseudo particles, unreacted lumps of quicklime powder are scattered, and the quicklime reaction rate is as low as 40 to 60% (normal).
As a result, the generation of pseudo particles is deteriorated, ungranulated iron-containing powder is generated, and the production of sintered ore when sintering using these pseudo particles is significantly less than 620 t / hr at maximum. Declined.
[0014]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and all changes in conditions and the like that do not depart from the gist are within the scope of the present invention.
For example , the position where the binder is added can be obtained by mixing the iron-containing powder on the belt conveyor with the binder mixed with air for transportation, or by applying an external force such as blowing air onto the binder falling from a feeder or the like. It is also possible to add in a dispersed manner, or to perform so-called divided addition divided into addition on the belt conveyor and addition in the granulator .
[0015]
【The invention's effect】
In the sintering material pretreatment method according to claim 1 , since the binder is dispersed and added to the iron-containing powder, the amount of the binder used can be reduced to improve the granulation yield, and the granulation cost can be reduced. can do. Moreover, the strength of the pseudo particles can be improved, and the productivity and quality of the sintered ore can be improved.
[0016]
In the pretreatment method of the sintered raw material according to claim 1 , since quick lime powder is used for the binder, good dispersibility and adhesiveness can be expressed, and the granulation efficiency can be further improved.
[0017]
In the pretreatment method of the sintered raw material according to claim 1 , since the binder is mixed with the gas and sprayed, the aggregation of the binder can be prevented to increase the granulation efficiency, and the quality of the pseudo particles can be stably improved. it can.
[0018]
In the pretreatment method of the sintering raw material according to claim 1 , since the solid-gas ratio of the binder is 100 or less, the binder can be added more uniformly, greatly improving the granulation efficiency and using the binder. Savings in volume are possible.
[Brief description of the drawings]
FIG. 1 is an overall view of a granulating apparatus applied to a sintering raw material pretreatment method according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the granulator taken along the line AA.
FIG. 3 is a graph showing the relationship between the air amount and the solid-gas ratio.
FIG. 4 is a graph showing the relationship between quicklime reaction rate and the production of sintered ore.
FIG. 5 is an overall view of a conventional granulating apparatus for a sintering raw material.
FIG. 6 is a schematic view of a cross section of a pseudo particle produced by a conventional granulator.
[Explanation of symbols]
10: Granulator, 11: Iron-containing powder, 12: Rotary kiln, 13: Chute, 14: Quicklime powder, 15: Quicklime powder supply pipe, 16: Belt conveyor

Claims (1)

In the pre-processing method of the sintering raw material which granulates the iron-containing powder by adding a binder to the iron-containing powder, the quick lime powder is used within 1 minute after adding quick lime powder to the binder and adding water to the iron-containing powder. Is mixed with gas so that the solid-gas ratio is 100 or less, sprayed onto the iron-containing powder, and the quicklime powder is dispersed and added to the iron-containing powder.

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