JP2011246302A - Method for treating air-cooled blast furnace slag, treatment device therefor, and method for producing roadbed material, aggregate, material for earthwork and ground improving material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating air-cooled blast furnace slag which can make air-cooled blast furnace slag into utilizable material in a short time while reducing the generation of harmful substances, and a treatment device therefor.SOLUTION: The method for treating air-cooled blast furnace slag includes: an extraction step (steps S101 to 103) of, after the storage of air-cooled blast furnace slag and water into a pressure resistant vessel, warming the pressure resistant sealed container to make the stored water into high temperature-high pressure water of 150 to 300°C, and, by the contact between the produced high temperature-high pressure water with the air-cooled blast furnace slag, extracting a sulfur component in the air-cooled blast furnace slag into the high temperature-high pressure water; and an exhaust step (step S104) of, after the completion of the extraction step, exhausting the high temperature-high pressure water in the pressure resistant vessel.

Description

  TECHNICAL FIELD The present invention relates to a method for treating blast furnace slow-cooled slag separated and recovered as a by-product when producing pig iron in a blast furnace and a treatment apparatus therefor. In addition, the present invention relates to a method for manufacturing a roadbed material, an aggregate, an earthwork material, and a ground improvement material using blast furnace slow-cooled slag treated by the treatment method as a raw material.

  Conventionally, blast furnace slow-cooled slag has been used as roadbed materials, aggregates, earthwork materials, and ground improvement materials, but if blast furnace slow-cooled slag that has just been taken out of the blast furnace and cooled is used as it is for slag, etc. Sulfur contained therein is dissolved by rain water and the like, and becomes cloudy water (hereinafter referred to as “yellow water”) and flows out to the surroundings, which may adversely affect the environment. For this reason, granulated slag is piled up outdoors and then shipped after aging for several months, but for aging, it was necessary to secure a vast site and manage it before shipping. .

  On the other hand, as a technique for preventing and treating yellow water from the slag, after the oxidation treatment to fix sulfur to the sulfur-containing slag, the uncarbonated calcium in the slag is carbonized. A method for producing a molded body in which slag is solidified is disclosed (for example, see Patent Document 1).

  In addition, a method for removing sulfur from used slag that can be reused as a desulfurization material in a steelmaking process by heating the desulfurization slag to 900 ° C. or higher in a carbon dioxide gas atmosphere is disclosed (for example, see Patent Document 2). ).

  Furthermore, the processing method of the reduced slag which reduces a sulfur content by making hot water or water vapor | steam contact a reduced slag and hydrolyzing the sulfur content in reduced slag is disclosed (for example, refer patent document 3).

  Further, a method for producing a low-sulfur concentration blast furnace slow-cooled slag in which a gas of 70 ° C. or more containing 15 to 50% by volume of water vapor is blown at a flow rate of 0.03 m / min to 30 m / min is disclosed (for example, Patent Document 4). reference).

Furthermore, after supplying pressurized steam to a pressure vessel charged with steelmaking slag and discharging condensed hot water and steam mixed with air, the steelmaking slag is hydrated in a saturated steam atmosphere of ² to 10 kg / cm ² G. An aging method of steelmaking slag to be reacted is disclosed (for example, see Patent Documents 5 and 6).

  Moreover, the method of oxidizing and removing the sulfur in molten slag by spraying the gas containing oxygen to molten slag is disclosed (for example, refer patent documents 7-9).

Japanese Patent No. 3714229 JP 2008-308754 A JP 2008-163391 A JP-A-9-118549 Japanese Patent No. 3193869 JP-A-9-118550 JP-A-55-97408 JP-A-53-90193 JP 59-125386 A

  However, the method described in Patent Document 1 requires a period of at least about several tens of hours to several days for the oxidation of the sulfur content in the sulfur-containing slag, and further requires a time of about one day for the carbonic acid treatment.

  Moreover, the method of patent document 2 needs to heat slag to about 900-1000 degreeC, and an energy cost becomes high.

  The methods described in Patent Documents 3 and 4 are not preferable because the hydrolysis and oxidation treatment of the sulfur content in the slag requires several days, and the generated harmful hydrogen sulfide and SOx are released into the atmosphere.

  The methods described in Patent Documents 5 and 6 are aging methods aimed at hydration of free calcium oxide (free lime) in steelmaking slag, and what is the possibility of sulfur removal in steelmaking slag by the method? It is not described, and it is not clear whether yellow water can be prevented by this method.

  Moreover, the method of patent documents 7-9 is a desulfurization method about the sulfur contained in the molten slag, and there existed a problem that it was not applicable to the already cooled slag.

  The present invention was devised in view of the above circumstances, and while reducing the release of harmful substances such as hydrogen sulfide and SOx into the atmosphere with respect to the blast furnace slow cooling slag generated in the pig iron manufacturing process in the blast furnace, It is an object of the present invention to provide a processing method and a processing apparatus capable of making a material usable in a short time. Furthermore, an object of the present invention is to provide a method for producing a roadbed material, an aggregate, an earthwork material, and a ground improvement material that prevent the generation of yellow water using the blast furnace slow-cooled slag treated using the treatment method and the treatment apparatus as a raw material. And

  In order to achieve the above object, the method for treating blast furnace slow cooling slag according to the present invention is such that after the blast furnace slow cooling slag and water are contained in a pressure vessel, the water contained by heating the pressure vessel is 150 to 300. The extraction step of extracting the sulfur content in the blast furnace slow cooling slag into the high temperature high pressure water by contact with the generated high temperature high pressure water and the blast furnace slow cooling slag after completion of the extraction step, A discharge step of discharging the high-temperature and high-pressure water in the pressure vessel.

  The blast furnace slow cooling slag treatment method of the present invention is characterized in that, in the above invention, the discharge step discharges water in the pressure vessel while maintaining a high temperature and high pressure state.

  Moreover, the processing method of the blast furnace slow cooling slag of this invention WHEREIN: The mass ratio of the blast furnace slow cooling slag used in the said extraction process and water shall be 1: 5 or more.

  In the blast furnace chilled slag treatment method of the present invention, in the above invention, the extraction step is performed by supplying a predetermined amount of high-temperature and high-pressure water adjusted to a predetermined temperature to the pressure vessel containing the blast furnace chilled slag. While maintaining the high-temperature and high-pressure state in the pressure-resistant vessel, the high-temperature and high-pressure water is continuously supplied into the pressure-resistant vessel and discharged to extract the sulfur content in the blast furnace slow cooling slag into the high-temperature and high-pressure water. It is characterized by.

  Moreover, the processing method of the blast furnace slow cooling slag of this invention is the said invention. WHEREIN: After the said discharge | emission process, it supplies water in the said pressure | voltage resistant container, and the high-temperature / high pressure-treated sulfur content which remains on the said blast furnace slag surface is extracted. A re-extraction step is included.

  In addition, the method for producing the roadbed material, aggregate, earthwork material and ground improvement material of the present invention uses the blast furnace annealed slag treated by the treatment method described above as a raw material, and the roadbed material, aggregate, earthwork material, and At least one of the ground improvement materials is manufactured.

  Further, the blast furnace slow cooling slag processing apparatus of the present invention has a pressure vessel containing the blast furnace slow cooling slag, supply means for supplying water to the pressure vessel, and a lid for containing the pressure vessel. Heating means for heating the pressure vessel to make the water in the pressure vessel 150 to 300 ° C. high-temperature high-pressure water, discharging means for discharging the high-temperature high-pressure water in the pressure vessel, and the high-temperature high-pressure water After the sulfur content in the blast furnace slow cooling slag is extracted into the high temperature and high pressure water by contacting with the blast furnace slow cooling slag for a predetermined time, the high temperature and high pressure water is drained while maintaining the high temperature and high pressure state in the pressure vessel. And a control means for controlling the discharge from the discharge.

  In the blast furnace slow cooling slag treatment apparatus according to the present invention, in the above invention, the supply means includes heating means for generating high-temperature high-pressure water at 150 to 300 ° C., and the control means is provided in the pressure-resistant vessel. After supplying a predetermined amount of the high-temperature and high-pressure water from the supply means, the high-temperature and high-pressure water is continuously supplied into the pressure-resistant container by the supply means and the drainage means while maintaining the high-temperature and high-pressure state in the pressure-resistant container. And discharging control is performed.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the material which can process and use a blast furnace slow cooling slag in a short time, reducing the discharge | release to the atmosphere of harmful substances, such as hydrogen sulfide and SOx. Furthermore, according to the present invention, a roadbed material, an aggregate, an earthwork material and a ground improvement material that can prevent the generation of yellow water can be produced in a short time.

1 is a cross-sectional view of a blast furnace slag treatment apparatus according to Embodiment 1 of the present invention. FIG. 2 is a flowchart of blast furnace slow cooling slag processing according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing the relationship between water temperature and saturated water vapor pressure. FIG. 4 is a cross-sectional view of a blast furnace slow cooling slag treatment apparatus according to Embodiment 2 of the present invention. FIG. 5 is a flowchart of blast furnace slow cooling slag processing according to Embodiment 2 of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a method for treating blast furnace slow cooling slag and a treatment apparatus thereof according to the present invention will be described in detail with reference to the accompanying drawings.

  It is well known that when water is in a liquid state at a high temperature and a high pressure, that is, a so-called subcritical state, the ionic product increases and has a large hydrolysis action. On the other hand, the blast furnace slow-cooled slag generated in the pig iron process in the blast furnace contains sulfur, such as sulfur, sulfide (calcium sulfide, etc.), sulfite and pyrosulfate. And it can be expected that these sulfur components are hydrolyzed by contact with the high-temperature and high-pressure water, and can be extracted into the high-temperature and high-pressure water mainly as sulfate or sulfite.

  The present invention treats blast furnace slow-cooled slag generated in a pig iron process in a blast furnace with high-temperature and high-pressure water, thereby extracting sulfides that cause yellow water generation with high-temperature and high-pressure water and discharging them without precipitation. Thus, the present invention was devised on the assumption that the blast furnace slow cooling slag can be used in a short time. In the following description of the present application, a roadbed material represented by JIS A 5015 “steel slag for road”, an aggregate material represented by JIS A 501-1 “slag aggregate for concrete”, an earthwork material, and ground improvement The materials are sometimes collectively referred to as “roadbed materials”.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a blast furnace slow cooling slag treatment apparatus 100 according to Embodiment 1 of the present invention. The processing apparatus 100 accommodates a blast furnace chilled slag and serves as a reaction tank that contacts with high-temperature and high-pressure water, a hot-water supply line system 5 that supplies hot water to the pressure-resistant airtight container 3, and a pressure-resistant airtightness. A heater 4 for heating the container 3 and using the internal water as high-temperature and high-pressure water, a treated water discharge line system 6 for discharging the high-temperature and high-pressure water in the pressure-resistant sealed container 3 after the high-temperature and high-pressure treatment, and each part are controlled. And a control unit 12.

  The pressure-resistant airtight container 3 has an openable / closable lid 15 for accommodating the blast furnace slow cooling slag in the container. In order to perform the high-temperature high-pressure water treatment according to the first embodiment, the pressure-resistant sealed container 3 has a structure that can withstand a pressure of about 0.5 to 30 Mpa. Furthermore, it has the structure sealed so that the pressure added to the accommodated high temperature / high pressure water is not missed. The pressure-resistant sealed container 3 is placed on a container moving carriage 2 that can freely move on the container moving rail 1. The container moving rail 1 is laid so as to connect the place where the blast furnace slow cooling slag is placed / cooled and the heater 4 for the heat-resistant airtight container 3, and the blast furnace slow slag is placed at the place where the blast furnace slow cooled slag is placed / cooled. After the cold slag is accommodated in the heat-resistant airtight container 3, the heat-resistant airtight container 3 is transported into the heater 4 by moving on the container moving rail 1 with the container moving carriage 2.

  The hot water supply line system 5 includes a hot water tank 9 for storing hot water to be supplied to the pressure-resistant sealed container 3, a heater 7 for heating the hot water in the hot water tank 9, and a temperature for detecting the temperature of the hot water in the hot water tank 9. A sensor 8, a liquid feed pump 10 for feeding hot water in the hot water tank 9 to the pressure-resistant airtight container 3, and a pressure adjusting valve 11 for adjusting the opening / closing and supply amount of the hot water supply line system 5 are provided. In the present embodiment, the hot water supply line system 5 is used to reduce the heating load of the heater 4, but the heater 7 may not be provided and water may be supplied to the heat-resistant airtight container 3.

  The quantity ratio between the blast furnace slow cooling slag and water supplied to the pressure-resistant airtight container 3 is that the compound eluted in the high temperature high pressure water by treating the blast furnace slow cooling slag with the high temperature high pressure water is treated, for example, during the discharge of the treated water. It is preferable that the supply amount of water and the blast furnace slow cooling slag is 1: 5 or more by mass ratio so that it does not precipitate in the pipe and cause clogging of the pipe. Further, in order to reliably immerse the blast furnace chilled slag in high-temperature and high-pressure water and perform high-temperature and high-pressure treatment, the total charged amount (total amount of blast furnace chilled slag and water) is set to 5 of the volume of the pressure-resistant sealed container 3. % Or more is preferable, and 50% or more is preferable in order to increase the processing amount per time.

  The heating heater 4 includes an openable / closable lid 16 for housing the pressure-resistant sealed container 3 and a temperature sensor 13 for detecting the temperature in the heating heater 4. The heating heater 4 heats the pressure-resistant airtight container 3 to a predetermined temperature, for example, 150 to 300 ° C., in order to use hot water supplied from the hot water supply line system 5 in the pressure-resistant airtight container 3 as high-temperature high-pressure water. The heating heater 4 according to Embodiment 1 has a structure that accommodates the heat-resistant airtight container 3, but if the water in the heat-resistant airtight container 3 can be high-temperature and high-pressure water at 150 to 300 ° C., the heat-resistant airtight container 3 is heat-resistant. It is good also as what added the heating means to airtight container 3 itself.

  The treated water discharge line system 6 includes a pressure regulating valve 14 that adjusts the opening and closing of the treated water discharge line system 6 and the discharge amount of high-temperature high-pressure water in the pressure-resistant sealed container 3.

  The control unit 12 is electrically connected to the above-described units and controls processing and operations of the units. The control unit 12 controls the heating heater 4 to purify the high-temperature and high-pressure water, and after bringing the blast furnace slow cooling slag and the high-temperature and high-pressure water in the pressure-resistant sealed container 3 into contact with each other for a predetermined time, Control is performed to discharge the high-temperature and high-pressure water in the pressure-resistant sealed container 3 while maintaining the high-pressure state. The discharge of the high-temperature and high-pressure water is performed while heating with the heater 4 so that the pressure and temperature in the pressure-tight airtight container 3 do not decrease due to the discharge of the high-temperature and high-pressure water while adjusting the discharge amount by the pressure regulating valve 14.

  As described above, it is preferable to discharge the high-temperature and high-pressure water while maintaining the high-temperature and high-pressure state in the heat-resistant airtight container 3, but when the ratio of sulfur contained in the blast furnace chilled slag as a raw material is low If the amount of water supplied into the pressure-resistant airtight container 3 is more than 5 times the amount of the blast furnace chilled slag, the high-temperature and high-pressure treated and extracted sulfur content in the high-temperature and high-pressure water is small, High temperature and high pressure water may be discharged from the sealed container 3.

  Next, with reference to FIG. 2, the process flow of blast furnace slow cooling slag is demonstrated. FIG. 2 is a flowchart of the blast furnace slow cooling slag process according to the first embodiment.

  First, a blast furnace slow cooling slag is charged into the pressure-resistant airtight container 3 (step S101). The blast furnace slow cooling slag to be charged is unaged and is equivalent to the grain size-adjusted steel slag (MS-25) of JIS A5015 except for coloration. Alternatively, a material that has been crushed in advance to a particle size close to the minimum particle size required according to the application is prepared.

  The pressure-resistant airtight container 3 charged with the blast furnace slow cooling slag is moved on the container moving rail 1 by the container moving carriage 2 and accommodated in the heater 4 for heating, and then the hot water supply line system 5 and the treated water are discharged. Connected to the line system 6. After the connection, the control unit 12 opens the pressure regulating valve 11 and supplies a predetermined amount of hot water stored in the hot water tank 9 in the pressure-resistant airtight container 3 by the liquid feed pump 10 (step S102).

  It is desirable that the amount of supplied water be at least five times the amount of slag to be charged. In the present invention, sulfur such as sulfur and calcium sulfide contained in the blast furnace chilled slag is extracted and removed to the treated water side by high-temperature high-pressure water treatment. It is estimated that the sulfur content such as calcium sulfide contained in the slag is converted to calcium sulfate by hydrolysis and oxidation by high-temperature and high-pressure water treatment. The amount of supplied water is set to 5 times or more of the amount of slag so that calcium sulfate produced by the high-temperature and high-pressure water treatment can be eluted to the treated water side as much as possible without precipitating. However, this is not the case when the amount of sulfur contained in the blast furnace annealed slag is low.

  The controller 12 closes the pressure regulating valve 11 of the hot water supply line system 5, then raises the temperature of the heater 4 for heating, and heats the water in the heat-resistant airtight container 3 to a high temperature and high pressure at a predetermined temperature of 150 to 300 ° C. The water is kept for a certain period of time, and the blast furnace slow cooling slag is treated with high-temperature and high-pressure water (step S103). The optimum treatment time varies depending on the particle size and sulfur content of the blast furnace slow-cooled slag, but a high temperature and high pressure water treatment at 150 to 300 ° C. can be sufficiently treated in about 2 to 3 hours. Further, the water pressure of the high-temperature high-pressure water is set to be equal to or higher than the saturated vapor pressure of water at the predetermined temperature described above. In addition, what is necessary is just to use a well-known method and a value for the calculation method of the saturated vapor pressure of water in predetermined temperature. FIG. 3 is a diagram showing the relationship between the water temperature and the water vapor pressure calculated by the Wagner equation shown by the following equations (1) and (2). According to FIG. 3, the saturated water vapor pressure of water is, for example, 0.48 MPa at 150 ° C. and 8.6 MPa at 300 ° C. From this, the saturated vapor pressure or higher of water at the predetermined temperature is, for example, 0.48 MPa or higher at 150 ° C. and 8.6 MPa or higher at 300 ° C.

ln (p × [kPa] Pc) = (Aτ + Bτ ^1.5 + Cτ ³ + Dτ ⁶ ) / (T / Tc)
(1)
τ = 1−T [K] / Tc (2)
In the above formulas (1) and (2), A = −7.76451, B = 1.45838, C = −2.7758, D = −1.23303, Tc = 647.3K, Pc = 22120 kPA (use range) 275K to 647.3K).

It is estimated that the sulfur content in blast furnace chilled slag, mainly calcium sulfide, is converted to calcium sulfate by hydrolysis and oxidation treatment with high-temperature and high-pressure water as shown in the following formula (3) by high-temperature and high-pressure water treatment. Is done. The solubility of calcium sulfate is at least 10 times that of calcium sulfide, and it is easily dissolved in water by being converted to calcium sulfate by high-temperature and high-pressure treatment, and can be easily removed from the blast furnace slag.
2CaS + 10H ₂ O → H ₂ SO ₄ + CaSO ₄ + Ca (OH) ₂ + 3H ₂ (3)

  After the high-temperature and high-pressure water treatment, the treated water is discharged from the pressure-resistant sealed container 3 (step S104). The controller 12 controls the heating of the heater 4 so as not to decrease the pressure and temperature in the pressure-resistant sealed container 3 while adjusting the pressure regulating valve 14 to control the discharge amount of the high-temperature and high-pressure water. In addition, when the ratio of the sulfur content in the blast furnace slow cooling slag is low, or when the supply amount of water into the pressure-resistant sealed container 3 exceeds 5 times the amount of the blast furnace slow cooling slag, the high temperature and high pressure water is treated. Therefore, the high-temperature and high-pressure water may be discharged from the heat-resistant airtight container 3 without heating by the heater 4.

  After discharging the high-temperature and high-pressure water, the blast furnace slag is dried in the heat-resistant sealed container 3 (step S105). By discharging the high-temperature and high-pressure water while maintaining the high-temperature and high-pressure state, the amount of water remaining in the heat-resistant sealed container 3 is low, and the drying time is shortened because the temperature is high.

  The blast furnace slow-cooled slag treated by the above flow does not show coloration, and the particle size distribution and expansion property are not changed from the properties before treatment, and as a grain size-adjusted steel slag (MS-25) of JIS A5015, Preferably used.

  Furthermore, the blast furnace slow-cooled slag treated by the treatment method described above is classified into “roadbed material” represented by “steel slag for road” in JIS A 5015 and “slag aggregate for concrete” in JIS A 5011-1. It can be used for applications such as representative aggregates, earthwork materials, and ground improvement materials. When these roadbed materials and the like are used, the blast furnace slow-cooled slag processed in the present embodiment is used as a raw material, and then manufactured by a known method. The roadbed material produced according to the present invention can effectively prevent the generation of yellow water.

  In this embodiment, particle size adjustment was performed in advance for use as a particle size-adjusted steel slag (MS-25) of JIS A 5015, but high-temperature high-pressure water has very high fluidity and permeability, The blast furnace slow-cooled slag as a raw material can penetrate into the slag lump and react without being pulverized into powder. Even when the present invention was applied to 0 to 40 mm slag that is usually available, it was confirmed in the JIS A 5015 color determination test that there was no coloration.

(Embodiment 2)
The method and apparatus for treating blast furnace slow cooling slag according to the second embodiment discharges the contact treatment between the blast furnace slow cooling slag and the high-temperature and high-pressure water while continuously supplying the high-temperature and high-pressure water directly to the pressure vessel. Let it be a flow process. The second embodiment can increase the supply ratio of the high-temperature high-pressure water to the blast furnace slow-cooled slag, so that when it is used as a raw material for roadbed materials or the like, the blast furnace slow-cooled slag treatment that more reliably prevents the generation of yellow water. Is possible.

  FIG. 4 is a cross-sectional view of a blast furnace slow cooling slag treatment apparatus 200 according to Embodiment 2 of the present invention. Only differences from the processing apparatus 100 according to the first embodiment will be described below.

  The processing apparatus 200 includes a high-temperature and high-pressure water supply line system 20 instead of the hot water supply line system 5. The high-temperature high-pressure water supply line system 20 includes a water storage tank 21 for storing water, a coil 23 for converting supplied water into high-temperature high-pressure water, and a heater 4 for heating the coil 23 to generate high-temperature high-pressure water. And a liquid feed pump 22 for feeding high-temperature high-pressure water to the hermetic pressure vessel 3 via the coil 23.

  The coil 23 is accommodated in a heating heater 4 that heats the pressure-resistant airtight container 3, and the water fed by the liquid feed pump 22 is heated while circulating through the coil 23 and converted into high-temperature high-pressure water. The In order to supply desired high-temperature and high-pressure water into the pressure-resistant airtight container 3 via the coil 23, the liquid feed pump 22 uses a pump having a maximum operating pressure that is equal to or higher than the desired pressure. In the second embodiment, the coil 23 and the pressure-resistant sealed container 3 are heated by the single heating heater 4, but another heating source may be provided.

  The control unit 24 controls the processing and operation of each unit, and after supplying a predetermined amount of high-temperature and high-pressure water into the pressure-resistant sealed container 3 by the high-temperature and high-pressure water supply line system 20, holds the high-temperature and high-pressure state in the pressure-resistant sealed container 3 However, the high-temperature high-pressure water supply line system 20 and the treated water drainage line system 6 are controlled so that the high-temperature high-pressure water is continuously supplied into the pressure-resistant sealed container 3 and discharged.

  Next, with reference to FIG. 5, the process of the blast furnace slow cooling slag which concerns on Embodiment 2 is demonstrated. FIG. 5 is a flowchart of the blast furnace slow cooling slag process according to the second embodiment.

  First, a blast furnace slow cooling slag is charged into the pressure-resistant airtight container 3 (step S201). As with the first embodiment, the blast furnace slow-cooled slag to be charged is not aged and is equivalent to the grain size-adjusted steel slag (MS-25) of JIS A5015 except for coloration. Alternatively, a material that has been crushed in advance to a particle size close to the minimum particle size required according to the application is prepared.

  After the pressure-resistant airtight container 3 charged with the blast furnace slow cooling slag is accommodated in the heater 4 for heating, it is connected to the high-temperature high-pressure water supply line system 20 and the treated water discharge line system 6. After the connection, the control unit 24 adjusts the temperature of the pressure tight container 3 and the coil 23 to a predetermined temperature of 150 to 300 ° C. by the heater 4 (step S202).

  After adjusting the temperature of the pressure-resistant airtight container 3 and the coil 23, a predetermined amount of high-temperature high-pressure water is supplied into the pressure-resistant airtight container 3 by the high-temperature and high-pressure water supply line system 20 (step S203). The water stored in the storage tank 21 is fed to the coil 23 by the liquid feed pump 22 and converted into high-temperature and high-pressure water by circulating through the coil 23 adjusted to a predetermined temperature. To be supplied.

  The controller 24 supplies a predetermined amount of high-temperature and high-pressure water into the pressure-resistant sealed container 3 through the high-temperature and high-pressure water supply line system 20, and then continuously supplies the high-temperature and high-pressure water into the pressure-resistant sealed container 3 through the high-temperature and high-pressure water supply line system 20. At the same time, the pressure regulating valve 14 of the treated water drainage line system 6 is adjusted so as to be discharged from the pressure-resistant sealed container 3. The control unit 24 adjusts and controls the liquid feed pump 22 and the pressure regulating valve 14 to maintain the pressure and temperature in the pressure-resistant airtight container 3 and to treat the stored blast furnace slow cooling slag with high-temperature and high-pressure water (step). S204). The treatment time varies depending on the particle size and sulfur content of the blast furnace slow-cooled slag and the amount of high-temperature high-pressure water supplied, but in high-temperature high-pressure water treatment at 150 to 300 ° C., it can be sufficiently treated in about 2 to 3 hours. .

  After the high-temperature and high-pressure water treatment, the treated water is discharged from the pressure-resistant sealed container 3 (step S205). After stopping the liquid feeding pump 22, the control unit 24 controls the heating of the heating heater 4 so that the pressure and temperature in the pressure-resistant sealed container 3 do not decrease, while treating the high-temperature high-pressure water in the pressure-resistant sealed container 3 with treated water. Discharge from the discharge line system 6. In the second embodiment, since the high temperature and high pressure water is flow-processed so as to be continuously supplied to and discharged from the pressure-resistant sealed container 3, the sulfur extracted in the high temperature and high pressure water is continuously supplied from the treated water discharge line system 6 together with the high temperature and high pressure water. Are being discharged. For this reason, the sulfur content concentration in the discharged high-temperature and high-pressure water is a very small value as compared with the first embodiment. Therefore, after treatment with high-temperature and high-pressure water, even if the pressure drops to normal pressure before discharging the treated water, there is little reprecipitation of the sulfur content, and the post-treated water at normal pressure may be discharged.

  After discharging the high-temperature and high-pressure water, the blast furnace slag is dried in the heat-resistant sealed container 3 (step S206). By discharging the high-temperature and high-pressure water while maintaining the high-temperature and high-pressure state, the amount of water remaining in the heat-resistant airtight container 3 is low, and the drying time is shortened because the temperature is high.

  In the second embodiment, since the supply amount of the high-temperature high-pressure water can be set large by performing the flow process by simultaneously supplying and discharging the high-temperature high-pressure water, the blast furnace gradual cooling slag into the pressure-resistant sealed container 3 is provided. The initial charging amount can be set larger than that of the first embodiment, and the processing amount per time can be increased. Moreover, since it is easy to increase the high-temperature and high-pressure water amount ratio with respect to the blast furnace slow cooling slag, it becomes possible to remove the sulfur content with certainty.

  Furthermore, the blast furnace slow-cooled slag treated by the treatment method described above is classified into “roadbed material” represented by “steel slag for road” in JIS A 5015 and “slag aggregate for concrete” in JIS A 5011-1. It can be used for applications such as representative aggregates, earthwork materials, and ground improvement materials. When these roadbed materials and the like are used, the blast furnace slow-cooled slag processed in the present embodiment is used as a raw material, and then manufactured by a known method. The roadbed material and the like manufactured according to the present invention can more effectively prevent the generation of yellow water.

  After containing the blast furnace slow-cooled slag (sulfur content 0.50%) adjusted to a particle size of 2 mm or less in the pressure vessel and water five times as much as the blast furnace slow-cooled slag, It hold | maintained for 6 hours in the air oven adjusted to 300 degreeC. After a predetermined time, the pressure vessel was taken out from the air oven and allowed to cool, and the water in the pressure vessel was filtered with 5B filter paper, and the slag was allowed to stand at room temperature and dried. About the slag after a high temperature / high pressure process, the coloration test was implemented in accordance with the coloration determination test method of the steel slag for JIS A 5015-1992 and the steel slag of Annex 1, and the presence or absence of coloration was determined. The results are shown in Table 1.

  As shown in Table 1, it is determined that there is coloration up to a treatment temperature of 100 ° C., and it can be inferred that the sulfur that is the cause of yellow water generation is insufficiently removed. It was observed that by treating the cold slag, there was no coloration.

  The hydrolyzing action of high-temperature and high-pressure water is greatest at around 200 to 250 ° C. where the ionic product of water is maximized, and heat treatment significantly exceeding 250 ° C. places a burden on facilities and energy. There is a possibility that the solubility of sulfate that is considered to be generated by hydrolysis is lowered, and the amount of sulfate remaining in the slag is increased. In addition, when the water temperature exceeds 374 ° C., which is 22.1 Mpa, the dielectric constant of water is greatly reduced. Therefore, it is considered that ionic substances such as thiosulfate ions and orthosulfate ions, which are thought to be generated by hydrolysis, are used. It becomes difficult to dissolve sulfur oxide ions. Furthermore, as the pressure and temperature increase, equipment with a large apparatus configuration is required. Therefore, it is preferable that the treatment with high-temperature and high-pressure water at 300 ° C. or lower is practical.

  As mentioned above, the processing method and processing apparatus of the blast furnace slow cooling slag of this invention can be used also for the slag generate | occur | produced in another steelmaking process. Furthermore, it can use also when manufacturing a roadbed material etc. by using as a raw material the slag which generate | occur | produces with the other steelmaking process processed with the processing method or processing apparatus which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 Container moving rail 2 Container moving cart 3 Pressure-resistant airtight container 4, 7 Heating heater 5 Hot water supply line system 6 Treated water discharge line system 8, 13 Temperature sensor 9 Hot water tank 10, 22 Liquid feed pump 11, 14 Pressure adjustment Valves 12, 24 Control unit 15, 16 Lid 20 High-temperature high-pressure water supply line system 21 Water tank 23 Coil 100, 200 Processing device

Claims (8)

After storing the blast furnace slow cooling slag and water in the pressure vessel, the water stored by heating the pressure vessel is changed to 150 to 300 ° C. high-temperature high-pressure water, and the generated high-temperature high-pressure water and the blast furnace slow-cooling slag An extraction step of extracting the sulfur content in the blast furnace slow cooling slag into the high-temperature high-pressure water by contact with
After the completion of the extraction step, a discharge step of discharging the high-temperature high-pressure water in the pressure vessel
A method for treating blast furnace slow-cooled slag, comprising:   2. The method for treating blast furnace slow cooling slag according to claim 1, wherein the discharging step discharges high-temperature and high-pressure water in the pressure-resistant vessel while maintaining a high-temperature and high-pressure state.   The method for treating blast furnace annealed slag according to claim 1 or 2, wherein a mass ratio of the blast furnace annealed slag and water used in the extraction step is 1: 5 or more.   In the extraction step, after supplying a predetermined amount of high-temperature and high-pressure water adjusted to a predetermined temperature to the pressure-resistant vessel containing blast furnace chilled slag, the high-temperature and high-pressure water is added to the pressure-resistant vessel while maintaining the high-temperature and high-pressure state in the pressure-resistant vessel. The blast furnace slow-cooled slag treatment according to claim 1 or 2, wherein the sulfur content in the blast furnace slow-cooled slag is extracted into the high-temperature high-pressure water by continuously supplying and discharging into the pressure-resistant vessel. Method.   3. The method according to claim 1, further comprising a re-extraction step of supplying water into the pressure-resistant vessel after the discharging step to extract a high-temperature and high-pressure-treated sulfur content remaining on the surface of the blast furnace slag. Blast furnace annealing slag treatment method.   A blast furnace annealed slag treated by the treatment method according to any one of claims 1 to 5 is used as a raw material, and at least one of a roadbed material, an aggregate, an earthwork material, and a ground improvement material is produced. To manufacture roadbed materials, aggregates, earthwork materials and ground improvement materials. A pressure vessel containing blast furnace slag, and
Supply means for supplying water to the pressure vessel;
Heating means for heating the pressure vessel to make the water in the pressure vessel 150 to 300 ° C. high-temperature high-pressure water;
Discharging means for discharging high-temperature and high-pressure water in the pressure vessel;
After extracting the sulfur content in the blast furnace slow cooling slag into the high temperature and high pressure water by bringing the high temperature high pressure water and the blast furnace slow cooling slag into contact with each other for a predetermined time, while maintaining the high temperature and high pressure state in the pressure vessel, Control means for controlling to discharge water from the waste water treatment means;
A blast furnace slow cooling slag treatment apparatus comprising: The supply means includes a heating means for generating high-temperature high-pressure water at 150 to 300 ° C.,
The control means supplies a predetermined amount of the high-temperature and high-pressure water from the supply means into the pressure-resistant container, and then maintains the high-temperature and high-pressure state in the pressure-resistant container while the high-temperature and high-pressure water is supplied by the supply means and the drainage means. The blast furnace slow-cooling slag treatment apparatus according to claim 7, wherein control is performed to continuously supply and discharge water into the pressure vessel.

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