JP4879865B2 - Blast furnace granulated slag treatment method and blast furnace granulated slag - Google Patents

Description

  The present invention relates to a method for treating granulated blast furnace slag containing needle-shaped slag out of slag generated in a steel production process such as a steel mill, and to a granulated blast furnace slag produced thereby.

  Granulated blast furnace slag (hereinafter sometimes referred to simply as “slag”) is a granulated product obtained by injecting pressurized water into the blast furnace molten slag generated in the ironmaking process at the ironworks and quenching it. The slag. In recent years, from the viewpoint of resource depletion and environmental protection, there are increasing opportunities to use this granulated blast furnace slag as a substitute for natural sand in fields such as civil engineering and marine environment maintenance.

  The granulated blast furnace slag obtained by quenching molten blast furnace slag with pressurized water usually contains acicular soot that is solidified into a needle shape. Therefore, when a blast furnace granulated slag is used, if a person touches the slag containing a lot of needle-shaped ridges, there is an unpleasant irritation on the skin. Moreover, if slag containing a lot of needle-shaped ridges is used as sand as it is, fish and shellfish may avoid irritation caused by needle-shaped ridges, which may adversely affect the collection performance.

  As a method for removing such needle-shaped soot contained in blast furnace granulated slag, for example, a crushing process by a crusher as disclosed in Patent Document 1 is widely known. Further, Patent Document 2 discloses a method of separating only needle-shaped ridges from slag using a punching plate as a sieve member.

  On the other hand, since granulated blast furnace slag has latent hydraulic properties, even if it is slag alone, it will solidify if left still for a long time. The slag consolidated in this way can no longer be used as an aggregate for cement, or even as a sand-capping material, it is difficult for bottling organisms such as shellfish to inhabit, so the consolidation is suppressed until there is no practical problem. Measures such as consolidation delay processing are required.

  As such a method of delaying consolidation, for example, Patent Document 3 discloses a step of dispersing blast furnace granulated slag and a substance containing at least one of carbon dioxide and carbonated water in the dispersed blast furnace granulated slag. A method for treating ground granulated blast furnace slag having a step of contacting is disclosed.

  Patent Document 4 discloses a method for preventing consolidation of granulated slag in which blast furnace granulated slag is brought into contact with carbon dioxide within 24 hours after light crushing.

JP-A-53-22522 JP 2006-181414 A JP 2003-335558 A JP-A-54-112304

  However, the above prior art has the following problems.

  In the method described in Patent Document 1, the needle-shaped ridges are crushed and reduced by the crushing process. However, there is a disadvantage that a new surface is generated in the slag by crushing, and elements such as calcium are eluted from the slag and solidify over time.

  Moreover, if it is the method described in patent document 2, a needle-shaped wrinkle can be sieved, but only a comparatively large needle-shaped wrinkle of 5 mm or more is disclosed, and 5 mm Nothing is stated about less than.

  On the other hand, according to the method described in Patent Document 3, by bringing a substance containing at least one of carbon dioxide and carbonated water into contact with blast furnace slag in a dispersed state, soluble lime on the surface layer of slag particles can be obtained. It can be changed to calcium carbonate to delay consolidation. In addition, slag is dispersed for efficient carbonate ion supply. However, since the force that crushes the needle-shaped ridge is not applied to the slag, this method cannot delay the consolidation, but cannot sufficiently reduce the needle-shaped ridge in the slag.

  In addition, the method described in Patent Document 4 merely describes a treatment method in which carbon dioxide gas is contacted within 24 hours after lightly crushing slag, and crushing strength necessary for crushing acicular scissors. There is no description about.

  As described above, according to the conventional technology, a method for treating granulated blast furnace slag capable of removing acicular crushing and sufficiently delaying consolidation, and a granulated blast furnace slag treated by this method have not been obtained.

  An object of the present invention is to provide a method for treating granulated blast furnace slag capable of realizing sufficient caking delay while appropriately removing needle-like soot, and a granulated blast furnace slag treated by this method. .

The gist of the present invention is as follows.
(1) A method for treating granulated blast furnace slag containing acicular soot, while crushing slag so that the value of Wm / Wi shown by the following [1 formula] is 0.037 or more, A method for treating granulated blast furnace slag, characterized by carbonizing slag at the same time.
^{_{Wm / Wi = 10 / (d}} 80) 1/2 - 10 / (d 80 (0)) 1/2 ··· [1 expression]
Wm: crushing work Wi: work index d ₈₀ : 80% passing particle diameter of the sample after crushing (μm)
d ₈₀ ⁽⁰⁾ : 80% passing particle diameter of the sample before crushing (μm )

  According to the method for treating granulated blast furnace slag according to the present invention, it is possible to carry out removal of needle-like ridges by crushing and efficient consolidation delay processing of a new surface caused by crushing. As a result, it is possible to obtain a slag that is not adversely affected by the needle-like flaws and that has been subjected to sufficient consolidation delay processing.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  The inventors of the present invention have studied various methods for satisfying both the removal of the needle-shaped slag of the granulated blast furnace slag and the caking delay, while removing the needle-shaped slag by crushing the slag with an appropriate impact force. By conducting the carbonation treatment at the same time as this crushing treatment, the new surface of the slag generated by crushing can be efficiently carbonated, and this has led to the new knowledge that a caking delay treatment can be carried out. Invented the invention. Hereinafter, the present invention will be described in detail.

  When examining the present invention, basic experiments on “removal of needle-like ridges” and “delay of caking” were conducted assuming sand-capping materials that require strict quality from the viewpoint of environmental conservation.

  First, regarding the removal of needle-shaped wrinkles, it was examined whether the number of needle-shaped wrinkles could be reduced to a practical problem.

  The needle-shaped slag targeted by the present invention is a needle-shaped slag having a major axis of 2.5 mm or more and an aspect ratio of major axis to minor axis of 1: 3 or more, which is contained in the granulated blast furnace slag. The number of ridges was the number of the above-mentioned needle ridges contained in 20 g of slag.

  The reason why the major diameter of the acicular ridge is set to 2.5 mm or more is that the maximum particle size of the granulated blast furnace slag is usually about 2.5 mm. It is because it is thought that it will protrude and an adverse effect will become apparent. Although the upper limit of the major axis of the needle-like ridge is not particularly specified, it is generally about 5 mm and about 7 mm at the maximum. In addition, the aspect ratio of the major axis and the minor axis is set to 1: 3 or more if the needle-like ridge has a sharp tip so as to affect the gathering property or the like. This is because the aspect ratio is 1: 3 or more if the needle-like ridges are 2.5 mm or more.

  In a concrete experiment, about 3 tons of granulated blast furnace slag was put into a concrete mixer, and an iron ball with a diameter of 50 mm was put into a stirring vessel for the purpose of crushing needle-shaped slag, and the slag was stirred by rotating the mixer. By doing so, the needle-shaped ridges were crushed. At this time, the number of iron balls and the stirring time were arbitrarily changed, and the number of needle-like ridges remaining in the slag after stirring was changed. Then, in order to investigate the practicality of these slags as sand-capping materials, the collection property of seafood, which is the main evaluation index, was evaluated. Incidentally, the number of needle-shaped ridges was visually separated from 20 g of the slag after stirring, and the number was counted.

  Evaluation of seafood collection was performed based on the contents disclosed in the “Fukuoka Prefectural Fisheries and Marine Technology Center Project Report H16-H17”. This is specifically shown below.

  A 1-ton type circular aquarium was divided into four equal parts, and “sea sand” and “test material” that was slag after stirring were spread alternately at a depth of 10 cm, and 4 shirogis were raised for 5 days without feeding with running water. Here, 5 days was set to 5 days as a period during which the influence of slag consolidation does not occur because it was found that consolidation of slag may start when 7 days or more are reached. Also, due to the limitation of 5 days, an experiment equivalent to the case where 4 shirogis were bred and 1 shirogis was bred for 20 days was conducted in a short period of time. The reason why Shirogis was selected for this evaluation is that it is a fish that inhabits the bottom sand, so that the influence of sand-capping material can be recognized.

At the time of breeding, once a day, it was observed whether shirogis was in the bottom sand of slag or sea sand, and the ratio of the total number of shirogis in the slag compartment was determined out of the total number of shirogis observed.
As a result, as shown in FIG. 1, the relationship between the number of needle ridges and the collection property is as follows. If the number of needle ridges per 20g of slag is 70 or less, the ratio of shirogisu in the slag area may be around 50%. found. This means that the percentage of shirogisu in the sea sand zone is also around 50%. Therefore, the collectability of slag that has been crushed to less than 70 needles per 20g of slag is It was found that it can be equivalent to

  Therefore, the crushing conditions necessary to reduce the number of needle-shaped ridges per 20 g of slag to 70 or less were investigated. The physical properties such as slag hardness are not only the components of the slag itself, but also various factors such as the temperature just before the molten slag begins to quench and solidify, the concentration of nitrogen dissolved in the slag, and the cooling conditions of the slag As a result, the conditions necessary for crushing acicular scissors also change. Generally, if the slag components are the same, the temperature of the molten slag immediately before starting to solidify is lower, and the slag after solidification becomes harder as the cooling rate during cooling is faster. As a result, it is known that the conditions necessary for crushing the needle-shaped ridge vary somewhat depending on the properties of the slag.

  However, the present inventors have found that Bond's fracture theory (“Bond, FC, Wang, JT, Trans. AIME, 187, 871 (1950)” or “Bond, FC, Trans”). AIM, 193, 484 (1952)), and dividing the crushing work Wm by the work index Wi which is an index indicating the crushability of the sample, Wm / Wi represented by the following [Formula 1]: The correlation between the number of needle-shaped ridges after the crushing treatment was separately examined using various blast furnace granulated slag containing needle-shaped ridges. As a result, it was found that there is a good correlation between them, and it was found that this can be used as an indicator of conditions necessary for crushing acicular scissors.

^{_{Wm / Wi = 10 / (d}} 80) 1/2 - 10 / (d 80 (0)) 1/2 ··· [1 expression]
Wm: crushing work Wi: work index (measurement method is defined in JIS M 4002)
d ₈₀ : 80% passing particle diameter of the sample after crushing (μm)
d ₈₀ ⁽⁰⁾ : 80% passing particle diameter of the sample before crushing (μm)

In addition, the value of Wm / Wi does not directly determine the value of Wm or Wi, but the 80% passing particle diameter “d ₈₀ ⁽⁰⁾ ” of the sample before crushing shown above and 80% of the sample after crushing pass. The particle diameter “d ₈₀ ” can be obtained and the difference can be obtained.

Incidentally, the above-mentioned “d ₈₀ ⁽⁰⁾ ” and “d ₈₀ ” can be obtained from the result of examining the relationship between the particle diameter and the passing mass percentage by sieving.

  Accordingly, the relationship between Wm / Wi and the number of needle-shaped scissors was examined for the sample used in FIG. 1 by varying the number of needle-shaped scissors in the slag. As a result, as shown in FIG. 2, it was found that when Wm / Wi is 0.037 or more, the number of needle-like ridges per 20 g of slag can be made 70 or less. Therefore, when the slag is crushed so that Wm / Wi is 0.037 or more by the method described later, the needle-like ridge can be appropriately removed when used as a sand covering material.

In addition, although the upper limit of Wm / Wi is not particularly defined, it means that the slag is crushed into a finer powder as the value increases. Therefore, when aiming to use natural sand as an alternative material, the upper limit of Wm / Wi is 0.095, which is a value at which the particle size after crushing is equivalent to that of natural sand. Recommended from the aspect. As a reference, FIG. 3 shows the relationship between d ₈₀ ⁽⁰⁾ and d ₈₀ when Wm / Wi = 0.037 and 0.095.

  From the practical point of view, even if the upper limit value of Wm / Wi is 0.080, it can be used as an alternative material almost equivalent to natural sand.

  Next, the caking slag consolidation delay was examined.

  When a new surface is generated in the slag by crushing, elements such as calcium are eluted from the slag with the passage of time, and the pH may increase and the slag may be easily consolidated. For this reason, as a method for delaying the consolidation of slag, the carbonation of slag was studied.

  Specifically, when the carbonation treatment is performed at the time of slag crushing, and when a predetermined standing time is set after the slag crushing and then the carbonation treatment is performed, the alkali eluted from the slag after the carbonation treatment The pH was checked in minutes. The pH was measured according to the measurement method described in “Method and explanation of soil test, first revised edition” (published by the Geotechnical Society of Japan, March 20, 2000, first printing, Maruzen). 100 ml of distilled water was added to a beaker containing 20 g of slag so as to satisfy the ratio of 1: 5, and the mixture was allowed to stand for 30 minutes after stirring until suspended with a stirring rod.

In the experiment, when slag crushing and carbonation are performed at the same time (ie, when there is no standing time), a concrete mixer with a stirring vessel capacity of about 10 m ^{3 and} a granulated blast furnace slag of about 3 tons and an iron ball with a diameter of 50 mm are used. Thirty pieces were put, and carbonation treatment was performed at a rotation speed of 3 rpm of the vessel while blowing a normal temperature gas containing 20% by volume of carbon dioxide into the stirring vessel at a flow rate of 2 m ³ / min. The total treatment time was 9 times every 30 minutes from 1 hour to 5 hours.

On the other hand, when the carbonation is performed separately after standing for a predetermined time after slag crushing, first the crushing of the needle-shaped rice cake by the above stirring is performed in the air instead of the carbon dioxide atmosphere, Remove the iron ball and let stand for 12 hours, and then perform carbonation treatment at a rotation speed of 3 rpm of the container while blowing a normal temperature gas containing 20% by volume of carbon dioxide into the stirring container at a flow rate of 2 m ³ / min. It was. The treatment time was set to 7 types every 30 minutes from 1 hour to 4 hours.

  As a result, as shown in FIG. 4, the relationship between Wm / Wi and pH was set to 12 hours after slag crushing, compared with the pH when carbonation was performed simultaneously with slag crushing. It was found that the pH was higher when the crystallization treatment was performed. Therefore, when the standing time of 12 hours was set, it was confirmed that the slag is easily consolidated because the pH rises even if the carbonation treatment is performed thereafter.

  In addition, since the pH of water in the vicinity of neutral pH rises sharply even when a slight amount of alkaline component is eluted, the pH of the slag rises quickly if elements such as calcium begin to elute from the new surface of the slag immediately after crushing. I have also confirmed that. However, by carrying out the carbonation treatment simultaneously with the crushing, the elution of the alkali component immediately after the crushing can be suppressed, and the pH increase due to this can be remarkably suppressed.

  From the above, it has been found that it is necessary to carbonize the new surface of slag generated by crushing simultaneously with slag crushing.

Incidentally, when CO ₂ gas is used for the carbonation treatment, the amount of carbon dioxide is not particularly limited, and any gas containing carbon dioxide may be used. However, since carbon dioxide reacts with calcium through pore water on the slag surface in the carbonation treatment, the solubility of carbon dioxide gas in water decreases as the treatment temperature increases, and the carbonation reaction does not proceed easily. For this reason, the treatment temperature is preferably 80 ° C. or lower, preferably 60 ° C. or lower.

As the gas containing carbon dioxide, industrially, for example, in an ironworks, it is efficient to use exhaust gas discharged from various factories. Typical exhaust gases include exhaust gas from a kiln factory that burns lime (approximately 20% by volume as a CO ₂ concentration), exhaust gas from a heating furnace (approximately 7% by volume of CO ₂ ), and exhaust gas from a power plant (approximately ₂ % by volume of CO ₂ concentration). If the CO ₂ concentration of these exhaust gases is sufficient, sufficient carbonation treatment is possible. Further, the carbon dioxide supply form during the carbonation treatment may be not only gas but also liquid such as carbonated water, dry ice, etc., and the addition amount and addition conditions are appropriately determined by grasping by preliminary experiments, etc. Set it.

  As described above, even when blast furnace granulated slag containing acicular soot is applied to sand-clad materials that require strict quality from the viewpoint of environmental conservation, acicular soot is removed by appropriate crushing of the slag. At the same time, by performing carbonation treatment at the same time, the new surface of the slag generated by crushing can be efficiently carbonated, and this also makes it possible to achieve a solidification delay treatment. It is possible to efficiently produce the granulated blast furnace slag that has been delayed.

  Therefore, according to the present invention, as an application of granulated blast furnace slag, it can be used for a general application as a natural sand substitute material other than a sand-capping material, and can also be used as an aggregate as a raw material for cement. it can.

  Incidentally, when slag crushing is performed by setting the value of Wm / Wi to a desired value, it is necessary to confirm the processing conditions in advance by experiments for each apparatus used for slag crushing. Examples of the device for crushing slag include a mixer truck, a horizontal cylindrical mixer, a rocking and rotating mixer, a V mixer, and a double cone mixer.

  Here, as an example of a process using an actual machine, a case where a mixer truck is used is taken as an example, and carbonation treatment is performed while crushing slag, and the number of needle-like ridges contained in the slag is 70 or less in 20 g of slag. As the crushing conditions, the processing conditions such as the processing time for setting the value of Wm / Wi to 0.037 or more, the number of iron balls to be introduced, the number of rotations of the mixer, and the like were examined.

First, in an experiment relating to the processing time, about 3 tons of slag was put into a concrete mixer truck having a capacity of a stirring vessel of about 10 m ³ , and normal temperature gas containing 20% by volume of carbon dioxide was put into the stirring vessel at 2 m ³ / min. Carbonation was carried out while stirring for 6 hours at a rotational speed of 3 rpm while blowing at a flow rate of 5 rpm. During the process, the process was temporarily interrupted for 1 hour, 2 hours, and 4 hours from the start of the process, and the value of Wm / Wi was obtained by sampling slag by 5 kg each. At the same time, in order to increase the crushing energy during stirring, 20 iron balls with a diameter of 50 mm are put in a stirring vessel together with slag, and the other cases where carbonation treatment is performed under the same conditions are similarly Wm. The value of / Wi was determined. As a result, the relationship between the processing time and Wm / Wi shows a linear correlation between the processing time and Wm / Wi as shown in FIG. As the processing time increases and the particle size of the slag decreases, the energy required to reduce the particle size gradually increases, and even if the processing time is increased, the increase in Wm / Wi calculated from the particle size is moderate. However, in the case with the iron ball in FIG. 5, even when Wm / Wi becomes 0.05, a linear relationship is established between the stirring time and Wm / Wi.

  Similarly, even when there is no iron ball, if the Wm / Wi is up to about 0.05, the particle size of the slag does not decrease as the relationship between the stirring time and Wm / Wi deviates greatly from the linearity. It is known that there is a linear relationship between / Wi, and in order to make Wm / Wi 0.037 or less, it is inferred that stirring for about 15 hours is necessary under the condition of no iron ball. In addition, when 20 iron balls having a diameter of 50 mm were put and stirred, it was confirmed that the stirring time could be shortened to about 4.5 hours.

Next, in order to examine the relationship between the number of iron balls and Wm / Wi, carbon dioxide having a diameter of 50 mm is used in the same manner as described above in the case of treatment for 4 hours using 10, 20, and 30 iron balls. Was performed at a rotation speed of ³ rpm while blowing a normal temperature gas containing 20% by volume at a flow rate of 2 m ³ / min. As a result, as shown in FIG. 6, the relationship between the number of iron balls and Wm / Wi after 4 hours treatment shows a linear correlation between the number of iron balls and Wm / Wi. It was confirmed that the Wm / Wi could be increased to 0.037 or more when using 23 or more iron balls under the time processing conditions. By further increasing the number of iron balls, the efficiency of crushing the needle-shaped ridges can be increased, and an operation mode that shortens the required stirring time can be selected.

Furthermore, in order to investigate the relationship between the rotation speed of the stirring vessel and Wm / Wi, using 10 iron balls with a diameter of 50 mm, the rotation speed of the container was set to 3 of 1, 3, 5 rpm for the case of 4 hours treatment. In the same manner as above, the treatment was performed while blowing a normal temperature gas containing 20% by volume of carbon dioxide at a flow rate of 2 m ³ / min. As a result, the relationship between the rotational speed and Wm / Wi was found to be linearly correlated as shown in FIG. 7, and it was found that Wm / Wi could be increased to 0.037 or higher at a rotational speed of 5 rpm or higher. By grasping the relationship with Wm / Wi when the number of rotations is further increased, it is possible to select an operation mode that shortens the necessary stirring time.

  As described above, in the example of the carbonation treatment using the mixer truck, by changing the processing conditions such as the stirring time, the number of iron balls to be introduced, the number of rotations of the mixer, and the like, which are conditions specific to the mixer truck, Wm The condition for setting the value of / Wi to 0.037 or more can be confirmed in advance. Even when there is a need to set the value of Wm / Wi to a desired value of 0.037 or more, similarly, the processing conditions such as the stirring time of the mixer truck, the number of iron balls to be charged, the number of rotations of the mixer, etc. By changing it, the processing conditions can be confirmed in advance.

  Similarly, when crushing slag using a device other than a mixer truck, change the processing conditions peculiar to the device and confirm in advance the processing conditions for setting Wm / Wi to a desired value. Can do.

  Examples of the present invention and comparative examples will be described below.

  Table 1 shows the analysis results of chemical components of pre-treated granulated slag used in this experiment, and Table 2 shows the relationship between the opening of the sieving sieve and the percentage by weight in the classification test.

  The water content of the slag used was 7% by mass. Further, the number of needle-like ridges having a major axis of 2.5 mm or more and a major axis / minor axis of 3 or more included in the slag was about 170 / slag 20 g.

The slag was subdivided into about 3 tons and then placed on a concrete mixer truck having a container volume of about 10 m ³ . These slags were each subjected to carbonation treatment by changing the stirring time, the number of used iron balls, the number of revolutions of the stirring vessel, and the interval from crushing to carbonation, respectively. An iron ball having a diameter of 50 mm was used.

In Examples 1 to 6 and Comparative Examples 1 to 4, by stirring, a gas containing 20% by volume of carbon dioxide in the stirring vessel (the balance is air) was blown at a flow rate of 2 m ³ / min at room temperature. Carbonation treatment was performed. In addition, in the experimental methods of Comparative Examples 5 and 6, the stirring was performed in the atmosphere for 3 hours at a rotation speed of 3 rpm using an iron ball, and then left to stand for 12 hours or 24 hours except for the iron ball. Carbonation treatment was carried out at a rotation speed of 3 rpm for 3 hours while blowing a gas containing 20% by volume of carbon dioxide into the stirring vessel (the balance was air) at a flow rate of 2 m ³ / min at room temperature.

  Table 3 shows the processing conditions of Examples and Comparative Examples.

  Wm / Wi, the number of needle-shaped sharks, the collection property of seafood, and pH were measured for the slag after treatment in the examples and comparative examples in Table 3 by the methods described above. The seafood collection shown in Table 4 is based on the method disclosed in the aforementioned “Fukuoka Prefectural Fisheries and Marine Technology Center Business Report H16-H17” and is a short period of 5 days. The effect of consolidation is not subject to evaluation because it evaluates the effect of the condition.

The value of Wm / Wi was obtained from d ₈₀ and d ₈₀ ⁽⁰⁾ using [Expression 1]. At that time, d ₈₀ ⁽⁰⁾ may be obtained by plotting the relationship between the sieve opening in Table 2 and the passing mass percentage of the slag to obtain the value of 80% passing particle diameter (μm) of the slag, Since it has been confirmed that there is almost no problem in terms of accuracy even if the opening of the sieve mesh is between 1.2 mm and 2.5 mm by linear approximation, here, 80% passing particle diameter of slag (by linear approximation ( μm) was determined.

  In addition, regarding the slag after being crushed under the conditions of each Example and Comparative Example, the relationship between the opening of the sieve mesh and the passing mass percentage of the slag was obtained, and the 80% passing particle diameter of the slag (μm as in the above). ) Value.

  Furthermore, a consolidation evaluation test was performed assuming use as sand-capping material in actual sea areas. Regarding the consolidation evaluation of slag in the actual sea area, based on the contents disclosed in the “Fukuoka Prefectural Fisheries and Marine Technology Center Project Report FY2016-H17”, after slag installation in the actual sea area for a certain period, The method of evaluating the state of was used.

  Specifically, on the coast of Buzen Sea in Uzen, Uzen, Buzen City, Fukuoka Prefecture, a stainless steel box of 1m in length, 0.6m in width and 0.3m in depth is installed in a shallow water area about 50m from the coastline. The treated slag was put in and examined for consolidation after half a year from installation. The evaluation period was half a year from April to October, including the summertime when the temperature was high and the most likely to consolidate.

  Regarding the determination of the presence or absence of consolidation, the hardness of the center of the box is measured using a Yamanaka soil hardness tester (manufactured by Fujiwara Seisakusho), and as described later, many organisms have an adverse effect on aggregability. More than 15 mm was considered to be consolidated.

  In addition, the measuring method of the hardness by the said Yamanaka type | system | group soil hardness meter pressed the cone to the predetermined position perpendicularly | vertically to the flat test surface, and measured the indentation depth of the cone at this time.

  Also, as a preliminary test, sea sand and slag were mixed at various ratios, and test materials whose consolidation strength was changed by changing the ratios were set up for about 4 months. Therefore, we investigated whether shellfish and sandworms can be inhabited by the hardness of consolidation. As a result, when the hardness is 15 mm or more, these organisms are not seen, and it has been found that survival is difficult.

  The results are as shown in Table 4. In Examples 1 to 6, Wm / Wi satisfies 0.037 or more, needles having a major axis of 2.5 mm or more and an aspect ratio of major axis to minor axis of 1: 3 or more. The number of ridges was 70 or less per 20 g of slag, and the collecting property was about 50%, which was equivalent to sea sand as described above. Furthermore, in the demonstration test in the actual sea area, it did not consolidate in the long term, and a sufficient consolidating delay effect could be obtained.

  On the other hand, in Comparative Examples 1 to 4, Wm / Wi did not satisfy 0.037 or more, and the number of needle-like ridges exceeded 70 per 20 g of slag. Therefore, although there was no long-term consolidation, there was an adverse effect on accumulating properties due to needle-shaped wrinkles.

  Further, in Comparative Examples 5 and 6 with an interval from crushing to carbonation treatment, Wm / Wi satisfies 0.037 or more, and the number of needle-like ridges is 70 or less per 20 g of slag. Although the collection property was about 50%, solidification occurred and the long-term consolidation delay effect was insufficient.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

It is a figure which shows an example of the relationship between the number of needle-shaped ridges, and the collectability of fish of the blast furnace granulated slag crushed by changing intensity. It is a figure which shows an example of the relationship between the value of Wm / Wi, and the number of acicular ridges which remain | survives in the slag after a crushing process. It is a figure which shows an example of the relationship of 80% passage particle diameter of the slag before and after crushing in the case of Wm / Wi = 0.037 and 0.095. It is a figure which shows the difference in pH when the carbonation process is performed simultaneously with crushing, and when carbonizing after standing for 12 hours after crushing. It is a figure which shows an example of the relationship between the stirring time of a carbonation process, and the crushing work added to slag. It is a figure which shows an example of the relationship between the number of the iron balls used by stirring, and the crushing work added to slag. It is a figure which shows an example of the relationship between the rotation speed of the stirring container at the time of a carbonation process, and the crushing work added to slag.

Claims (1)

A method for treating granulated blast furnace slag containing acicular soot,
A method for treating granulated blast furnace slag, wherein the slag is crushed so that the Wm / Wi value represented by the following [1 formula] is 0.037 or more, and the slag is carbonized at the same time. .
^{_{Wm / Wi = 10 / (d}} 80) 1/2 - 10 / (d 80 (0)) 1/2 ··· [1 expression]
Wm: crushing work Wi: work index d ₈₀ : 80% passing particle diameter of the sample after crushing (μm)
d ₈₀ ⁽⁰⁾ : 80% passing particle diameter of the sample before crushing (μm)