JPS61126199A - Preparation of powder coke for sintered fuel - Google Patents

Abstract

PURPOSE:To obtain powder coke excellent in combustion rate, air-permeability, productivity and sinterability, by pelletizing and curing a mixture of specified powder coke and cement with addition of water and a quick-curing agent followed by disintegration by falling impact. CONSTITUTION:5-10% (inner percentage) high early strength cement or common Portland cement 22 is added to powder coke 5 contg. 16% or less particle of size >=3mm and 20-37% particle of size <=0.25mm and mixed 23. Then the mixture 24 is tumbled and pelletized 26 with addition of 2-7% (inner percentage) water 25 and a cement quick-curing agent in a pan pelletizer, etc. After the pelletized product 27 is cured 28 for at least one day, the cured product 29 is disintegrated 30 by giving falling impact caused by 1-2m fall from a shovel car to a dump car and 2-5m fall from the dump car to a delivery hopper, etc. to cleaply prepare powder coke of a particle size of 0.25-3.0mm in a high yield.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing coke breeze, which is used as a fuel for sintering sintering raw materials such as iron ore. Efficiency, air permeability, yield, productivity, reduction powdering index, FeO%NO! This invention relates to a method for producing coke breeze of 0.25+m to 3.0m with excellent sinterability such as conversion rate at low cost and with a high yield of 9.

[Conventional technology]

Figure 4 shows the results of an investigation conducted by the present inventor on the influence of coke breeze particle size on sinterability.
It has been learned that when K contains all the coke powder in the particle size range of 3.0 to 3.0, all indicators indicating sinterability become good.

FIGS. 1 and 2 are block diagrams of a conventional coke breeze manufacturing process. Generally, in the conventional process, 25 to 305 w+ of the undersieve of lump coke for blast furnace
The starting material is small and medium lump coke that cannot be used as blast furnace charging coke. Specifically, the first and second
As shown in the figure, the coke 1 produced in the coke manufacturing process is sieved by a sieve 2 of about 5 sieves, and the sieve 3 is further sieved by 3 sieves.
The coke is sieved by a sieve 4 with a diameter of about 0 m, and the sieve 5 is used as coke to be charged into a blast furnace. At that time, the small and medium coke cokes 8 and 9, which are stored in piles in the storage yard, are used in the sintered fuel coke powder manufacturing process. It is used as a starting material.

In the manufacturing process shown in FIG. 1, the coke 6 and sintering coke powder 15 are used.

When the classification point of the sieve 10 is 5 m (3 mm), the sieve 14 is 0.25 w or less (-0.25 wg
) is about 20-25 inches (30-34qb),
5 m (3 m
) or more will be shattered with a target of 5 chi or less, so +5 armor (
+3 order) is about 5 inches (5 inches), but -0,254 is about 32% (37%), and sintering powder coke 15 is 0.25 to 3.04 powder coke is 55 ~60% (6,
0 to 65 cm), -0.25 m coke powder is 25 to 30
% (30-35chi).

On the other hand, the manufacturing process in Figure 2 is the same as the process in Figure 1.
The starting material 8 and 9 supplied to the sieving machine 10 of the same process are subjected to a sizing and strengthening process 16t. The above process 16t! , cokes 8 and 9 in an appropriate ratio of 5 to 1
05m sieve separator 17, and the sieve top 1B is passed through roll mill 1.
9 for pulverization, and the pulverized coke 20 is sent to sieve machine 1 again.
7 and sieved together with coke 8 and 9, and sieved into sieve machine 1.
The under sieve 21 of No. 7 is supplied to the sieving machine 10 of the process shown in FIG.
The same processing operations as above were carried out to produce sintering powder coke 1.
5 is produced. The sintering coke powder 15 produced by the process shown in Figure 2 contains 60 to 65% coke powder of 0.25 to 3.0, and approximately 20 to 25 percent coke powder of -825. Compared to the 5W classification of the process shown in FIG. 1, the yield of 0.25 to 3.0 planes is improved by about 5 inches. In addition, the 3mmI classification and 0.25 of the process i in Figure 1
~3, the yield of Om is the same.

On the other hand, recently, coke dry extinguishing equipment (hereinafter abbreviated as CDQ) has been developed to achieve energy-saving effects in the coke manufacturing process.
is in operation, and from this CDQI7) primary and secondary dust collector, primary dust (primary CDQ powder) with an average particle size of 1.23 m,
Average particle size 0.122+a+, particle size composition -125μ27%
, 125-250 μs 1 inch, 250 μ-l m 21 inch, 1-2 wx 1 inch of secondary dust (secondary CDQ powder) is collected.

As a method of effectively utilizing this fine CDQ powder, there is a method of adding it to the sintering coke powder 15 produced by the manufacturing process shown in Fig. 1 or 2 above and using it as a part of the sintering coke powder. However, when secondary CDQ powder is added to coke powder 15 in the process of 3I+III classification (5m+g classification) in Figure 1, the amount of CDQ powder generated will contain 10% culm at the maximum internal rate, and there .2
5-3.0 sea bream powder coke is 58-63% (53-58
h), -0,254 coke powder is 32-37% (27
~32%).

In addition, when the secondary CDQ powder is added to the coke breeze 15 of the @2 diagram process, the yield of coke breeze of 0, 25 to 3.0 tone is improved due to the addition of the grain size strengthening process 16 to the first process. This cancels out the effects, resulting in 5- in Figure 1.
0.0, which is about the same as sintering powder coke 15 in the classification process.
25~3.0 rent is 57~62chi, -0,25- is 23~
It becomes powder coke of about 28%.

In view of the above-mentioned circumstances, the present applicant has previously applied for patent application No. 58-4045.
In No. 4, a maximum of 101 (inner) secondary CDQ powder is added to the coke powder 15 produced by the conventional process shown in FIG. 3 sea bream or more, 161 or less, 0.25 m+ or less 2
By processing 0 to 37% coke breeze at low cost, the process shown in Figure 2 achieves 0
．． 25 to 3.0-5, which is the increased amount of coke powder
We proposed a method for producing coke powder for sintered fuel, which can achieve an increase in effect over 100%.

This proposed method has a particle size structure of 3 tones or more, 16 to 16, as shown in Figure 3.
Coke powder of 20-37% below 0.25 wm 1
A step 23 of adding 5 to 10% (inner amount) of early strength cement or ordinary Portland cement 22 to the mixture 24 and mixing it, and a step 26 of adding 2 to 7% (inner amount) of water 25 to the mixture 24 and rolling granulation. and Granules 27 for more than 1 day (in the case of early strength cement) or 2 days or more (in the case of ordinary Portland cement)
This method of producing coke powder for sintering is characterized by comprising a curing step 28 and a step 30 of crushing by impact of falling 29'ft of curing material. Note that this is 3111 finished coke flour.

In this proposed method, the particle size structure is 3s+ or more 6%, 0.25~
3. Ow 62 inches, 0.254 or less 32 inches of raw coke powder (raw coke) is added with 71 points of early strength cement,
The mixture was mixed for 4 minutes using a paddle mixer, and then granulated by rolling for 4 minutes using a pan pelletizer while adding 5% water to this mixture. 1-2 from excavator to dump truck
m fall and 2 to 5 m from the dump truck to the discharging hopper
When crushed by falling impact, it breaks down to 34 or more 7%, 0
．． 25-3.0 78%, 0.25 or less 0.2
Product coke (pseudo-granulated powder coke) with a high yield of 5 to 3.0 m can be obtained.

In this way, the proposed method crushes the coke powder that has agglomerated during curing by falling impact, and does not require any special crushing equipment. It is possible to naturally disintegrate the material with just one impact due to natural fall during delivery and transportation, reducing processing costs.

[Problem that the invention seeks to solve]

However, in the proposed method, curing time of at least 24 hours is required for loading the granules, and the curing time is 0.25 to 3.
A specific example of 0 and 16% improvement requires curing for 3 days (72 hours), requires a large indoor curing yard, and requires high equipment costs, resulting in high processing costs.

The present invention has been made in view of the above-mentioned problems, and provides a method for producing coke breeze for sintered fuel, which increases the amount of coke breeze by 0.25 to 3.0 i' in a short period of curing.

Its feature lies in the use of an additive that accelerates the hardening of cement, that is, a cement quick setting agent.

[Means for solving problems]

The gist of the present invention is that the particle size structure is 3 to 16 inches, 20 to 0.25 m or less.
A process of adding and mixing cement to 37% coke powder, a process of rolling granulation while adding water and a cement quickening agent to this mixture, a process of curing this granulated product, and a process of curing this curing agent. A method for producing coke powder for sintered fuel, comprising a step of crushing by falling impact, and a step of mixing cement and a cement quickening agent.

A step of adding and mixing this mixture to coke powder having a particle size of 3H or more and 16% or less and 0.254 or less and 20 to 37 inches, a step of tumbling granulation while adding water to this mixture, and a step of rolling granulation while adding water to this mixture; A method for producing coke powder for sintered fuel is characterized by comprising a step of curing an object and a step of crushing the curing material by a falling impact. .

Hereinafter, the effects of the present invention will be explained based on examples.

[7 Effects-Example] Raw material coke powder with water' + 8% with the particle size distribution shown in Table 1
0kg (dry equivalent) and ordinary Portland cement 700
g was mixed in a Nauta mixer for 15 minutes. 'Table 1' Next, the above mixture was tumble-granulated for 4 minutes by adding the cement quick-setting agent shown in Table 2, and the batch granulation was completed.The addition of water and the cement quick-setting agent was , 5% at the beginning of granulation
Water was sprinkled for 80 minutes, and then a cement quick-setting agent in the amount shown in Table 2 was added for 30 seconds.

Table 2 Next, this granulated product was cured for 5 to 11 molecules, subjected to a drop impact, vacuum dried without curing, and the particle size distribution was examined using a sieve.

The above drop impact is (1 m x 1 time) and (3 m x a time).
A case was also investigated which was subjected to a fall impact and then subjected to secondary curing for 60 minutes.

Incidentally, the curing of the granules and the drop impact crushing were carried out by storing the batch granules in a plastic bag.

Table 3 shows the results of these tests, that is, the yield of finished coke (rapidly set pseudo-granulated powder coke) from 0.25 to 3.0 m. In addition, 0.25 to 3.0 of the 3-day curing product according to the proposed method
Haruyoru is in charge of 77.

After pre-mixing cement and quick-setting agent, this mixture is added to raw coke powder and mixed, and then water is added to this mixture and tumble granulated to obtain the same results as in Table 3 even if added just in case. I was able to do that.

From the above investigation results, it is important to appropriately select the type and j# of the quick setting agent, that is, QP-500!
By adding , DENKA-ESzo%, and 10% Na2CO3, the yields of 0.25 to 3.0■ were all the same as the 3-day cured product by the proposed method, and the change in yield due to the magnitude of impact was small. It is clear that the curing time can be shortened.

Next, using QP-soo and Na2COB among the above-mentioned quick-setting agents, it was cured for 4 hours in an indoor curing yard, and then taken out from the curing yard to the raw material tank of the sintering equipment, and dropped by 3 m x 4 times in the conveyance system. Assuming a process in which the sintered material is impact crushed, charged into the raw material tank of the sintering equipment, where it remains for 16 to 24 hours, and then mixed with the sintering raw material as sintering fuel, the sintered material obtained under the following creative conditions □ A pot firing test was conducted using pseudo-granulated coke powder.The amount of cement quick setting agent QP-500 added was 5.2°1.0
．． 5% to 4 levels, and Na1. The granulation process was carried out under the same conditions as above except that the amount of CO3(r) added was changed to two levels of 1005 yen, cured for 4 hours, and then aged for 3 hours.
The coke powder was crushed by applying a falling impact* m X J times to obtain rapidly solidified pseudo-granulated coke powder, and this coke powder was cured for 16 to 2.0 hours. In addition to this coke powder, a sintered raw material prepared by blending powdered ore of the particle size classification shown in Table 4, return ore, powdered lime, and electric furnace slag under the mixing conditions shown in Table 5 was heated in a pot under the firing conditions shown in Table 6. Fire and FFS.

K) We investigated x, etc. The results are shown in Table 7. Table 7 also shows the pot firing results when using normal coke (raw material coke powder) and pseudo-granulated coke powder (a-day cured product).

Table 4 Particle size classification table 5 Mixing conditions Table 6 Calcining conditions As shown in Table 7, pseudo-granulated coke powder obtained by pseudo-granulation of normal coke powder has an increased FFS than normal coke powder. , NOx reduction effect is recognized. From Table 7, when judging the quality of the rapidly setting pseudo-granulated coke powder produced by the method of the present invention based on the pseudo-granulated coke powder (3-day cured product), it was found that compared to the pseudo-granulated coke powder (3-day cured product) , especially QP-500,
For the 5% additive product, FFS increases, K) x f) E decreases,
Moreover, QP-500°21 and the product containing 10% of Na2CO3 obtained almost the same effect.

From Table 7, it is clear that the same effect as pseudo-granulated coke after 3 days of curing can be achieved with a short curing of 4 hours by selecting the type and amount of the quick setting agent.

For example, according to the method of the present invention, QP-500 or Na1CO1 is selected as the quick-setting agent, and it is added 2 to 5% or 101.11 degrees to ordinary Portland cement.
It is possible to reduce the processing cost by -1/6.

〔Effect of the invention〕

As described in detail above, according to the method of the present invention, coke powder with excellent sinterability can be obtained with short curing time, and the curing yard can be reduced.

[Brief explanation of the drawing]

tF, , FIG. 4 is a diagram showing the results of an investigation on the influence of coke breeze particle size on sinterability. Agent: Patent attorney Masamitsu Akizawa and 2 others

Claims (2)

[Claims] (1) A process of adding and mixing cement to coke powder having a particle size structure of 3 mm or more and 16% or less and 20 to 37% of 0.25 mm or less, and rolling granulation while adding water and a cement quick setting agent to this mixture. 1. A method for producing coke powder for sintered fuel, comprising: a step of curing the granulated material; and a step of crushing the curing material by a falling impact. (2) The process of mixing cement and cement quick setting agent, and the particle size of this mixture is 3 mm or more and 16% or less, and 0.25 m
A process of adding and mixing pulverized coke of 20 to 37% less than m, a process of rolling granulation while adding water to this mixture, a process of curing this granulated product, and a process of curing this curing material by dropping impact. 1. A method for producing coke powder for sintered fuel, comprising the step of crushing.