JP3241161B2 - Slag crushing and aging treatment methods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a steelmaking slag in which crushing and hydration are accelerated by bringing solidified high-temperature steelmaking slag into contact with a large amount of cooling water, and further reducing the residual expansion rate of the slag. Aging treatment method for shortening the slag aging treatment period.

[0002]

2. Description of the Related Art In conventional steelmaking slag processing, slag carried out of a steelmaking factory is discharged onto a pit or an iron plate and subjected to various processing steps such as temporary crushing, temporary cooling, secondary cooling and pit submergence cooling. You. The slag subjected to these treatments is left in a cooling yard for about one to two days to be naturally cooled, then subjected to secondary crushing, magnetic separation and grinding, and iron and the like are recycled to a steelmaking process. The slag from which iron has been recovered is transported to an aging yard, and left for about 1 to 3 years to be used for civil engineering and building materials, and then subjected to an aging treatment. This conventional processing method is uneconomical, requiring multiple steps, long processing times and large yards. Furthermore, since these series of processes are operations involving high temperature and dust, there is a problem in terms of safety and health.

[0003] In order to solve these problems, various techniques have been disclosed with respect to a slag aging treatment method. As one of the methods, a processing method for stabilizing, cooling and reforming slag described in Japanese Patent Publication No. 58-55093 discloses a method of solidifying a molten slag and then crushing the obtained slag to obtain a small piece of slag in a closed container. The slag is sprinkled with water, and the slag is aged and cooled by utilizing the pressure of the generated steam and a high-temperature atmosphere.
However, since this technique has a problem in a watering method, hydration does not sufficiently progress even if the treatment is performed for a long time, and aging is insufficient. In addition, since the crushing is not performed at all in this process, a post-process of the crushing process and the aging process is required in order to be usable for civil engineering and the like.

[0004] Also, Japanese Patent Publication No. Sho 59-12613 discloses that
A method for improving steelmaking slag into slag suitable for road materials, harbor construction, and the like in a short time is disclosed. This method promotes the hydration reaction of free lime in the slag by immersing the steelmaking slag in the yard and immersing it in warm water at 60 to 100 ° C for 1 to 3 weeks. I have to. Even with this technique, aging for a period of about 1 to 3 weeks is required to satisfy the residual expansion rate of 2% or less, which is a use standard for civil engineering building materials. Therefore, in this treatment method, a large area hot water pit is required to treat the entire amount of slag by this treatment method.
The amount of land secured and capital investment is enormous, making it difficult to apply to actual operations. Furthermore, no hydration reaction takes place inside the large slag, which requires sorting of this large slag after this treatment.

[0005] The applicant of the present invention has disclosed in Japanese Patent Application No. 4-97699 that the sprinkling speed, steam pressure and processing time in a closed vessel filled with coarsely crushed high-temperature slag are limited, and the self-crushing is carried out by rapid cooling and hydration. Treatment (Slag Quench) which causes hydration on the new fracture surface
Process). 30 of this processing method
The slag having an average slag particle size of 11 to 18 mm and a residual expansion rate of 3 to 12% (average 8%) is obtained by the treatment for minutes.

[0006]

SUMMARY OF THE INVENTION The present invention provides a steel slag which has been roughly crushed and which has been subjected to the above-mentioned SQ treatment of the present applicant to crush the slag and promote the hydration reaction, and then is generated by the SQ treatment. The heat of slag and the heat of hydration reaction of high-temperature steelmaking are effectively used for the aging treatment with warm water in the subsequent process, achieving the 2% residual expansion rate required for civil engineering building materials in a very short time. And it aims at treating the aging of steelmaking slag economically and safely.

[0007]

According to the present invention, there is provided a slag crushing treatment and aging treatment method, wherein a mechanically coarsely crushed high-temperature slag is filled into a core container in a pressure vessel. After sealing the pressure vessel, 5-30 ton / hr of cooling water was applied from above the slag packed bed.
Water pressure is applied at a watering density of ^{2, and} the water vapor generated by the contact between the cooling water and the high-temperature slag increases the water vapor pressure of the pressure vessel, and the relationship between the water vapor pressure and the treatment time is expressed by the following equation (1): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) where P: water vapor pressure (kg / cm ² ) T: treatment time (hr) The slag is aged, and crushed by rapid cooling with cooling water and slag expansion by a hydration reaction, and then the slag that has been subjected to the crushing and the aging is subjected to 80-1.
This is achieved by a slag crushing treatment and aging treatment method characterized by immersing in hot water at a temperature of 00 ° C. for 12 hours or more, and then performing aging with warm water.

Further, according to the present invention, in the method for crushing and aging slag, the temperature of the hot water is controlled to 80 to 100 by utilizing the steam generated by the contact between the cooling water and the high-temperature slag. It is achieved by a slag crushing treatment and aging treatment method characterized by maintaining the temperature at ℃.

[0009]

According to the method of the present invention for performing a two-stage treatment of steelmaking slag in which the SQ treatment and the subsequent hot water treatment are carried out, the hydration reaction is effectively and quickly promoted by the first-stage SQ treatment. Due to the expansion of the hydration reaction, the slag is self-crushed, and the aging of the slag greatly progresses. Furthermore, aging of the slag further progresses by performing aging treatment with the second-stage warm water using the sensible heat recovered by the SQ treatment, and the product becomes a satisfactory product for civil engineering and building materials. The above-mentioned SQ treatment and hot water treatment method have tremendous effects on economy and safety, such as a drastic reduction of treatment time, simplification of treatment steps, reduction of treatment cost and equipment investment, as compared with the prior art. . The operation will be described below.

Free CaO present in steelmaking slag reacts with water or steam to cause a hydration (digestion) reaction represented by the following formula. CaO + H ₂ O = Ca (OH) ₂ +15.2 Kcal Calcium hydroxide (Ca (O)
Since H) ₂ ) expands in volume, the slag is self-crushed by calcium hydroxide generated in the slag. This hydration reaction proceeds at a relatively low temperature and is an exothermic reaction, and thus requires an appropriate cooling.

In the SQ treatment in which self-crushing and aging progress by rapid cooling and hydration reaction of the first-stage slag, a mechanically coarsely crushed high-temperature slag is filled in a core container in a pressure vessel. After closing the container, cooling water is sprinkled from above the slag packed bed at a sprinkling density of 5 to 30 ton / hrm ² . This sprinkling may be performed intermittently at intervals according to the conditions of the cooling and hydration reactions. 5 ton / hrm
^With a watering density of ² or more, cooling water is evenly applied to the slag packed layer and all slag in the container undergoes hydration reaction and rapid cooling without causing drift, and at the same time heat shrinkage due to rapid cooling and hydration reaction The hydration reaction proceeds further on the newly emerged fracture surface that has been fractured by expansion. Even if water is sprayed at a watering density exceeding 30 ton / hrm ² , the cooling rate of the slag does not change, and the steam in the pressure vessel is excessively cooled, so that external steam supply is required to maintain the pressure.

In the SQ treatment, the steam pressure in the pressure vessel is increased by the steam generated by the contact between the cooling water and the high-temperature slag and the steam injected from the outside, and the relationship between the steam pressure and the processing time is expressed by the following equation (1). ): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) However, P is maintained within the range specified by the following: steam pressure (kg / cm ² ) T: treatment time (hr) By specifying the steam pressure (P) and the treatment time (T), self-crushing occurs, and the self-crushing causes a further hydration reaction on the newly-appeared crushed surface. In order to lower the slag temperature, the exothermic hydration reaction is further promoted. By the short SQ treatment for about 30 minutes, the residual expansion rate due to unreacted slag is 3 to 12%.
(Average 8%). In order to reduce the residual expansion rate of the slag to 2% or less, which is suitable for sale, the conventional laying method required an aging period of 12 to 36 months for the atmospheric exposure of the slag. However, the slag in the state where the SQ processing method is performed is reduced to the aging period of the atmospheric exposure of 6 to 9 months.

In order to reduce the residual expansion rate to 2% or less in a shorter period of time, in the present invention, the slag subjected to the SQ treatment is more efficiently and economically treated.
An aging treatment is performed in a second stage of warm water immersed in warm water at a temperature of ° C. for 12 hours or more. This hot water aging treatment is preferably performed at 90 ° C. or higher and hot water having an average temperature of 95 ° C. This aging treatment with hot water may be performed in the above-mentioned pressurized container. In this case, the opening / closing portion or the exhaust valve at the top of the pressure container is opened to atmospheric pressure. Further, it may be performed in another arbitrary container or a bathtub such as a pool provided separately. In this aging treatment with warm water, S
Hot water heated using steam generated during the Q treatment or steam supplied from outside, or hot water supplied from outside may be used. By using the warm water heated by using the steam generated during the SQ treatment, the cost of using the hot water can be reduced to zero, which has a great effect on reducing the aging treatment cost.

According to the two-stage treatment method of the present invention in which the hot water treatment is further performed after the SQ treatment, the steelmaking slag can be crushed and aged in a very short time.
Aging processing for up to 36 months is not required. In addition, since the aging time can be greatly reduced as compared with the conventional aging method using only hot water, the hot water tank equipment required for the aging processing can be small in scale, and the amount of capital investment can be greatly reduced. Hereinafter, the present invention will be described in more detail with reference to examples.

[0015]

[Embodiment] Second embodiment of the present invention in which a hot water treatment is further performed after the SQ treatment
The results of the converter slag, the PS-free slag and the ingot slag treated by the step treatment method and the conventional treatment method are shown below. FIG. 1 shows the particle size accumulation curves of converter slag, PS slag, and lumps treated by the two-stage treatment method of the present invention and the conventional aging treatment method using only hot water. In the converter slag of FIG. 1A, the slag subjected to the hot water aging treatment for 24 (+), 48 (△), and 72 (▽) after the SQ treatment of the present invention has a particle size accumulation curve of slag. Aging treatment using only warm water of the prior art is performed using 24 (□), 48 (◇), and 72 (×).
All of them are located on the upper left side of the grain size accumulation curve of the slag subjected to time. This indicates that the slag that has undergone the two-stage treatment according to the present invention undergoes slag refinement due to aging. Similarly, the results of the two-stage treatment method according to the present invention are superior to those of the prior art treatment method for the PS removal slag (b) and the lump slag (c) shown in FIG.

FIG. 2 shows the hot water treatment time and collapse of the converter slag (a), the PS removal slag (b) and the ingot slag (c) which have been treated by the two-stage treatment method of the present invention and the treatment method of the prior art. Degree DP5
The relationship with the particle diameter of 0 (the particle diameter when the slag passing weight ratio through the sieve becomes 50%, representing the average particle diameter of the slag) is shown.
From the results of the hot water treatment time on the particle size of the degree of disintegration DP50, in the two-stage treatment method of the present invention, the particle size can be almost satisfied by the warm water treatment for 24 hours. The degree of collapse of the slag crushed by the two-stage treatment method of the present invention is determined by the converter slag (a) and the removal of PS.
Both the results of the slag (b) and the ingot slag (c) were superior to the results of the prior art processing method, and the effect was the greatest in the converter slag (a).

FIG. 3 shows the hot water treatment time and remaining time of the converter slag (a), the PS removal slag (b), and the ingot slag (c) which have been treated by the two-stage treatment method of the present invention and the treatment method of the prior art. This shows the relationship with the expansion coefficient. When the treatment is performed by the two-stage treatment method of the present invention, the 2% residual expansion rate at which the converter slag (a), the PS removal slag (b), and the ingot slag (c) can be sold is 12 hours or less. Achieved well in processing time. The two-stage treatment method of performing the hot water treatment after the SQ treatment of the present invention has an aging effect superior to the conventional treatment method using only hot water.

[0018]

The crushing of steelmaking slag by the two-stage treatment method of performing the SQ treatment and the subsequent hot water treatment according to the present invention has a particularly large crushing effect on converter slag, and the conventional technology can also be applied to the removal of PS slag and ingot slag. The effect is greater than that of the above treatment, and the treatment time is sufficiently achieved within 24 hours.

Aging of steelmaking slag by the two-stage treatment of the present invention can achieve a residual expansion rate of about 2% or less within 12 hours in any of converter slag, de-PS slag and ingot slag. An aging effect suitable for sale is obtained. Accordingly, the converter slag and ingot slag need not be aged in the yard, and can be immediately sold.

[Brief description of the drawings]

FIG. 1 shows particle size accumulation curves of converter slag (a), PS slag (b), and ingot slag (c) treated by a two-stage treatment method of the present invention and a treatment method of the prior art. .

FIG. 2 shows converter slag (a) treated with a two-stage treatment method of the present invention and a conventional treatment method using only hot water, and removal of PS.
Warm water aging and crushing treatment time of slag (b) and lumps (c) and disintegration degree DP50 (the slag passing weight ratio is 50
%, Which represents the average particle size of the slag).

FIG. 3 shows hot water treatment time and residual expansion rate of converter slag (a), PS slag (b), and ingot slag (c) treated by the two-stage treatment method of the present invention and the conventional treatment method. The relationship is shown below.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shinji Matsuo 1 Nishinosu, Oita, Oita City, Oita Prefecture Inside Nippon Steel Corporation (72) Inventor Tsukasa Kashiwara 1 Nishinosu, Oita Oita City, Oita New Japan (56) References JP-A-5-295409 (JP, A) JP-A-6-256047 (JP, A) JP-A-6-247753 (JP, A) JP-A-54-1979 2295 (JP, A) JP-A-5-296673 (JP, A) JP-B-58-55093 (JP, B2) JP-B-59-12613 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C21C 5/28

Claims (2)

(57) [Claims] 1. A method for crushing and aging slag, wherein a high temperature slag mechanically coarsely crushed is filled in a core container in a pressure vessel, the pressure vessel is sealed, and then the slag is filled above the slag filling layer. From the above, the cooling water is sprinkled at a sprinkling density of 5 to 30 ton / hrm ² , and the steam pressure of the pressure vessel is increased by the steam generated by the contact between the cooling water and the high-temperature slag, and the relationship between the steam pressure and the processing time is determined. The following formula (1): 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) where P: water vapor pressure (kg / cm ² ) T: treatment time (hr) While maintaining, aging of the coarsely crushed high-temperature slag is performed, and crushing is performed by rapid cooling with cooling water and slag expansion by a hydration reaction, and then the slag subjected to the crushing and the aging is 80 to 1
A slag crushing treatment and aging treatment method, wherein the slag is immersed in hot water at a temperature of 00 ° C. for 12 hours or more, and further subjected to aging with warm water. 2. A method for crushing and aging slag, wherein the temperature of the hot water is adjusted to 80 to 100 by utilizing the steam generated by the contact between the cooling water and the high-temperature slag.
The method for crushing and aging slag according to claim 1, wherein the slag is maintained at a temperature of ° C.