Aging treatment method for steelmaking slag and manufacturing method for slag material

Abstract

To provide an aging processing method of a steel making slag and a production method of a slag material, capable of easily grasping a progress state of aging processing in an inner layer without requiring installation and recovery of a measuring facility in the inner layer of a laminated steel making slag.SOLUTION: An aging processing method of a steel making slag to carry out aging processing for the steel making slag has: a moisture supply start process of starting supplying moisture from a moisture supply device to the steel making slag; a specific resistance value calculation process of calculating a specific resistance value of the steel making slag by using an electric current electrode and a potential electrode installed on a surface of the steel making slag; and a progress state determination process of determining a progress state of the aging processing based on the specific resistance value calculated in the specific resistance value calculation process.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for aging steelmaking slag used as roadbed material or coarse aggregate for concrete, and a method for producing slag material. [Background technology]

[0002] The steel slag produced in integrated steelworks includes blast furnace slag, which is produced when iron ore is melted and reduced in a blast furnace, and steelmaking slag, which is produced during the steelmaking stage when pig iron is refined. The produced steel slag is then piled up in a cooling yard and slowly cooled by natural cooling and the addition of an appropriate amount of moisture. It is then crushed and sieved, and aged as necessary, before being used as roadbed material or coarse aggregate for concrete.

[0003] Among iron and steel slags, steelmaking slag contains free lime (free CaO) and / or free MgO (hereinafter referred to as "free lime, etc."). When steelmaking slag containing free lime, etc. is used as road base course material or coarse aggregate for concrete, the free lime, etc. contained in the steelmaking slag reacts with water, etc., causing volume expansion, which leads to the collapse of the road base course material or coarse aggregate for concrete.

[0004] For this reason, it is necessary to thoroughly remove free lime and other substances during the aging process of steelmaking slag. In other words, during the aging process, moisture is supplied to the stacked steelmaking slag, and the reaction between the free lime and other substances that cause expansion and collapse and the moisture (water flow or steam) is promoted, thereby stabilizing the steelmaking slag. Research has been conducted on technologies for monitoring the progress of the aging process of steelmaking slag stacked in a cooling yard during the aging process.

[0005] Non-Patent Document 1 discloses a method for managing the aging time of steelmaking slag during steam aging treatment by installing a thermocouple above the slag layer and monitoring the progress of the aging treatment based on the temperature measured by the thermocouple. Patent Document 1 also discloses an insulating cover for steam aging of steelmaking slag that has a hole for inserting a thermocouple. Patent Document 2 discloses a method for controlling the amount of steam supply based on the measured values ​​of multiple thermometers embedded inside the slag layer during steam aging treatment of steelmaking slag. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7120841 [Patent Document 2] Japanese Patent Application Publication No. 4-175250 [Non-patent literature]

[0007] [Non-Patent Document 1] Development of steam aging treatment for steelmaking slag, Sasaki et al., Nippon Steel & Sumitomo Metal Techniques, 399 (2014), p.21 Summary of the Invention [Problem to be solved by the invention]

[0008] However, although the techniques disclosed in Non-Patent Document 1 and Patent Document 1 enable temperature measurement of the outer layer of steelmaking slag by installing a thermocouple on the surface of the outer layer, it is difficult to measure the temperature of the inner layer of steelmaking slag. For this reason, even if the techniques disclosed in Non-Patent Document 1 and Patent Document 1 are used, it is not possible to obtain temperature information in the inner layer of steelmaking slag, i.e., the progress of the aging treatment in the inner layer, and it is difficult to perform an accurate aging treatment taking into account the progress.

[0009] Furthermore, the technology disclosed in Patent Document 2 enables measurement of the temperature of the inner layer of steelmaking slag by embedding multiple thermometers in the inner layer of the steelmaking slag, but requires a great deal of effort to install and retrieve the multiple thermometers in the inner layer before and after the aging treatment.

[0010] Furthermore, the techniques disclosed in Non-Patent Document 1 and Patent Documents 1 and 2 involve measurements based on installing a thermometer in the outer or inner layer of the steelmaking slag, and therefore the measured value is temperature information at a specific position in the outer or inner layer of the steelmaking slag, and is therefore local temperature information. Therefore, it is difficult to grasp the overall progress of the aging treatment in the outer or inner layer of the steelmaking slag, and it is difficult to control the amount of moisture supply based on the progress of the aging treatment in the inner layer and to accurately calculate the treatment time required for the aging treatment.

[0011] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a method for aging steelmaking slag and a method for manufacturing slag material that make it possible to easily grasp the progress of the aging treatment in the inner layer of stacked steelmaking slag without requiring the installation and recovery of measuring equipment in the inner layer. [Means for solving the problem]

[0012] [1] A method for aging steelmaking slag, comprising: a moisture supply starting step of starting the supply of moisture from a moisture supply device to the steelmaking slag; a resistivity calculation step of calculating the resistivity of the steelmaking slag using a current electrode and a potential electrode installed on the surface of the steelmaking slag; and a progress determination step of determining the progress of the aging treatment based on the resistivity calculated in the resistivity calculation step. [2] The progress status determination process determines the end of the aging process based on the resistivity value calculated by the resistivity value calculation process becoming less than a threshold value. [1] A method for aging steelmaking slag as described in [1]. [3] The aging treatment method for steelmaking slag according to [2], wherein the threshold value is 700 Ω·m. [4] A method for aging steelmaking slag as described in [1], further comprising, after the progress status determination process, an additional processing time calculation process for calculating the additional processing time required for the aging process or a control process for controlling the moisture supply device. [5] A method for producing a slag material, which comprises producing the slag material by the method for aging steelmaking slag according to any one of [1] to [4]. [Effects of the Invention]

[0013] According to the present invention, the progress of the aging treatment in the inner layer of stacked steelmaking slag can be easily grasped without the need to install and retrieve measuring equipment in the inner layer. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a schematic configuration as an example of an electrical exploration (resistivity method). [Figure 2] FIG. 1 is a diagram illustrating a schematic configuration of an example of a progress status determination device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, "upper layer" refers to the uppermost layer of the stacked steelmaking slag. "lower layer" refers to the lowermost layer of the stacked steelmaking slag. "Middle layer" refers to any layer of the stacked steelmaking slag in the vertical direction, excluding the "upper layer" and "lower layer." Furthermore, "upper surface" refers to the upper surface of the stacked steelmaking slag. "Side" refers to the lateral surface of the stacked steelmaking slag. "Lower surface" refers to the lower surface of the stacked steelmaking slag. "Surface" collectively refers to the upper surface, side surface, and bottom surface of the stacked steelmaking slag. Furthermore, "outer layer" includes the surfaces (upper surface, side surface, and bottom surface) of the stacked steelmaking slag and refers to the surface layer of the steelmaking slag that has a predetermined thickness toward the center of the stacked steelmaking slag. "Inner layer" refers to any inner layer of the stacked steelmaking slag, excluding the outer layer.

[0016] 1 shows the configuration for measuring resistivity values ​​based on electrical exploration (resistivity method) used in this embodiment. Electrical exploration is a type of geophysical exploration in which a current (I) is passed through a pair of current electrodes attached to the surface of the outer layer of the steelmaking slag to be measured, and the potential difference (V) is measured between another pair of potential electrodes to determine the electrical properties of the steelmaking slag and investigate the progress of the aging treatment inside (inner layer) of the steelmaking slag.

[0017] As shown in Figure 1, electrical exploration uses a pair of current electrodes A and a pair of potential electrodes V. An electric field is formed in the inner layer of the steelmaking slag S by passing a current through the pair of current electrodes A and applying a voltage to the steelmaking slag S with the pair of potential electrodes V.

[0018] Then, with an electric field formed in the inner layer of the steelmaking slag S, the resistivity value of a measurement point N in the inner layer of the steelmaking slag S, between a pair of current electrodes A and a pair of potential electrodes V, is calculated. The measurement point N is located inside the formed electric field. The calculated resistivity value is then taken as a value (resistance value) related to the electrical resistor in the inner layer between the pair of current electrodes A and the pair of potential electrodes V, and the distribution of the substance (moisture) contained in the electrical resistor (steelmaking slag S) can be grasped. Specifically, if the steelmaking slag S contains a lot of moisture, the resistivity value will be small. On the other hand, if the steelmaking slag S contains a lot of coarse particles and little moisture, the resistivity value will be large.

[0019] Here, taking into consideration the distance between the surface of the outer layer of the steelmaking slag S and the measurement point N in the inner layer of the steelmaking slag S, it is preferable to set the distance between the pair of current electrodes A and the pair of potential electrodes V to 1 m. For the same reason, it is also preferable to set the distance between the pair of current electrodes A and the pair of potential electrodes V to 1 m.

[0020] As shown in FIG. 1, the distance D (m: meters) between the midpoint C between the pair of current electrodes A and the pair of potential electrodes V and the measurement point N located inside the electric field is expressed by the following equation (1): D = (a × n + a) / 2 (1) Here, a represents the distance (m: meters) between the pair of current electrodes A and the pair of potential electrodes V, and n represents the value obtained by dividing the distance between the pair of current electrodes A and the pair of potential electrodes V by a. For ease of measurement, it is preferable to set n to "n=1".

[0021] Furthermore, when a pair of current electrodes A and a pair of potential electrodes V are installed on the surface of the upper layer of the steelmaking slag S, the position of the electric field formed in the depth direction of the inner layer of the steelmaking slag S can be changed by changing the distance between the pair of current electrodes A and the pair of potential electrodes V, or the distance between the pair of current electrodes and the pair of potential electrodes. Specifically, by decreasing the distance between the pair of current electrodes A and the pair of potential electrodes V, or the distance between the pair of current electrodes and the pair of potential electrodes, an electric field can be formed in the inner layer of the steelmaking slag S at a position closer to the upper layer of the steelmaking slag S (a shallower position). On the other hand, by increasing the distance between the pair of current electrodes A and the pair of potential electrodes V, or the distance between the pair of current electrodes and the pair of potential electrodes, an electric field can be formed in the inner layer of the steelmaking slag S at a position closer to the lower layer of the steelmaking slag S (a deeper position).

[0022] Therefore, by applying electrical exploration (resistivity method) using a pair of current electrodes A and a pair of potential electrodes V, it is possible to calculate the resistivity values ​​at various positions in the depth direction of the inner layer of the steelmaking slag S, and the progress of the aging treatment (the moisture penetration status) at various positions in the depth direction of the inner layer of the steelmaking slag S can be grasped.

[0023] Furthermore, by providing an electrode configuration consisting of a pair of current electrodes A and a pair of potential electrodes V at multiple locations on the surface of the outer layer of the steelmaking slag S and calculating the resistivity value in the inner layer of the steelmaking slag S using all of the electrode configurations, the two-dimensional distribution of the progress of the aging treatment can be grasped.

[0024] In addition, electrode configurations each consisting of a pair of current electrodes A and a pair of potential electrodes V are provided at multiple locations on the surface of the outer layer of the steelmaking slag S, and the spacing between the pair of current electrodes A and the pair of potential electrodes V, or the spacing between the pair of current electrodes and the pair of potential electrodes, is changed for each of these multiple electrode configurations, and the resistivity values ​​are calculated using all of the electrode configurations, making it possible to grasp the three-dimensional distribution of the progress of the aging process.

[0025] When a pair of current electrodes A and a pair of potential electrodes V are installed on the surface of the upper or lower layer of the steelmaking slag S, in order to accurately calculate the resistivity value in the inner layer of the steelmaking slag S, it is preferable that the distance between the pair of current electrodes A and the pair of potential electrodes V, or the distance between the pair of current electrodes and the pair of potential electrodes, be equal to or less than the height of the loaded steelmaking slag S (see arrow T in Figure 2). This is because if the distance between the pair of current electrodes A and the pair of potential electrodes V, or the distance between the pair of current electrodes and the pair of potential electrodes, is larger than the height of the steelmaking slag S, the position of the electric field formed in the depth direction of the inner layer of the steelmaking slag S will be deeper than the thickness of the steelmaking slag S, and the resistivity value in the inner layer of the steelmaking slag S will not be accurately calculated.

[0026] The pair of current electrodes A and the pair of potential electrodes V may also be installed on the side of the steelmaking slag S. In this case, in order to accurately calculate the resistivity value in the inner layer of the steelmaking slag S, it is preferable that the distance between the electrodes or the distance between the pair of current electrodes and the pair of potential electrodes be equal to or less than the width (see arrow W in Figure 2) or depth distance (see arrow Q in Figure 2) of the steelmaking slag S. The depth distance means the length of the stacked steelmaking slag S in the depth direction of the drawing.

[0027] Furthermore, the pair of current electrodes A and the pair of potential electrodes V may be installed on the surface of the upper or lower layer of the steelmaking slag S, and may also be installed on the side of the steelmaking slag S. In this case, with respect to the pair of current electrodes A and the pair of potential electrodes V installed on the surface of the upper or lower layer of the steelmaking slag S, it is preferable that the distance between the electrodes or the distance between the pair of current electrodes and the pair of potential electrodes is equal to or less than the height of the steelmaking slag S (see arrow T in Figure 2). Furthermore, with respect to the pair of current electrodes A and the pair of potential electrodes V installed on the side of the steelmaking slag S, it is preferable that the distance between the electrodes or the distance between the pair of current electrodes and the pair of potential electrodes is equal to or less than the width (see arrow W in Figure 2) or depth distance (see arrow Q in Figure 2) of the steelmaking slag S to be stacked.

[0028] Furthermore, although the configuration of the current electrode A and potential electrode V shown in Figure 1 as an embodiment is a quadrupole arrangement in a dipole-dipole configuration, any configuration of the current electrode and potential electrode is possible as long as it is possible to calculate the resistivity value in the inner layer of the steelmaking slag S. That is, the present invention can be applied to a dipole arrangement in a pole-pole configuration, a tripole arrangement in an equally spaced CPP configuration, or other quadrupole arrangements such as the Wenner arrangement, the Eltlan arrangement, or the Schlumberger arrangement. However, in view of the accuracy of the calculation of the resistivity value, a dipole-dipole arrangement (quadrupole arrangement) is preferred.

[0029] Next, an embodiment of the steelmaking slag aging treatment method according to the present invention will be described with reference to Fig. 2. Fig. 2 shows a schematic configuration diagram of an example of a progress determination device 20. The progress determination device 20 includes a moisture supply device 12, a current electrode A, a potential electrode V, a control device 13, and a storage device 14.

[0030] In this embodiment, the current electrode A and the potential electrode V are provided on the surface of the upper layer ST, which is part of the outer layer of the steelmaking slag S stacked in the aging treatment plant 11, which is the aging site. In the present invention, the current electrode A and the potential electrode V may be installed on any surface of the outer layer of the steelmaking slag S. That is, the current electrode A and the potential electrode V may be installed on any surface of the top, side, or bottom of the stacked steelmaking slag S. Furthermore, the current electrode A and the potential electrode V may be installed in a surface range extending from the top to the side, a surface range extending from the side to the bottom, or on the top and bottom surfaces. The moisture supply device 12 receives a control signal from the control device 13 and is capable of supplying moisture to the lower layer SB of the steelmaking slag S based on the control signal. The moisture supply device 12 is capable of supplying moisture to the lower layer SB of the steelmaking slag S as a water flow, steam, or pressurized steam.

[0031] The control device 13 is composed of a general-purpose information processing device such as a personal computer or a workstation. The control device 13 is, for example, a CPU, and is connected to the device so as to receive measurement-related current and voltage information from the current electrode A and the potential electrode V. The control device 13 loads programs stored in the storage device 14 into the work area of ​​the main storage unit and executes the programs to perform various processes. The control device 13 receives measurement-related current and voltage information from the current electrode A and the potential electrode V and performs processing based on this information. The control device 13 is connected to the device so as to generate control signals based on the processed information and transmit the control signals to the moisture supplying device 12. The storage device 14 is, for example, an updatable flash memory, a hard disk built in or connected via a data communication terminal, a memory card, or other information recording medium and a read / write device for the same. The storage device 14 pre-stores programs for implementing various functions related to the slag aging process, as well as data used during execution of the programs.

[0032] In this embodiment, the aging treatment method for steelmaking slag may be carried out using the configuration shown in Fig. 2. That is, the aging treatment method for steelmaking slag may include a moisture supply starting step of starting the supply of moisture from the moisture supply device 12 to the steelmaking slag S, and a resistivity calculation step of calculating the resistivity of the steelmaking slag S using a current electrode A and a potential electrode V installed on the surface of the outer layer of the steelmaking slag S. Then, a progress determination step of determining the progress of the aging treatment based on the resistivity calculated in the resistivity calculation step may be carried out.

[0033] Therefore, by carrying out the steelmaking slag aging treatment method of the present invention, it is possible to easily grasp the progress of the aging treatment in the inner layer of the steelmaking slag S by using the current electrode A and potential electrode V installed on the surface of the outer layer of the steelmaking slag S, without the need to install and recover measuring equipment in the inner layer of the stacked steelmaking slag S.

[0034] Here, before the aging treatment of the steelmaking slag S, the steelmaking slag S to be subjected to the aging treatment may be stacked in the aging treatment plant 11. The steelmaking slag S may be stacked in an amount of 3,000 tons at a time. It is preferable to stack the steelmaking slag S in an amount of 100 to 10,000 tons at a time. The steelmaking slag S may be stacked to a height of 3 m using a wheel loader. Although there is no limit to the height of the stack of steelmaking slag S, it is preferable to keep it to 3 m or less from the viewpoint of work safety. The surface of the stacked steelmaking slag S may be leveled in consideration of the installation of electrodes. However, if it does not interfere with the installation of electrodes, there is no need to level the surface of the steelmaking slag S. The steelmaking slag S may be stacked by any method as long as the above-mentioned amount and stack height are acceptable.

[0035] First, in the moisture supply start step, the control device 13 may send a control signal to the moisture supply device 12 to start supplying moisture to the lower layer SB of the steelmaking slag S. The moisture supply may be a water flow supply to the lower layer SB of the steelmaking slag S, a steam supply, or a pressurized steam supply. The moisture may be supplied at a supply rate of 1 t / h at the start of the supply. Taking into account the predetermined processing time required for the aging treatment, the moisture supply rate is preferably 5 t / h or more at the start of the supply. In the resistivity value calculation step, the current electrode A and the potential electrode V may measure current information and voltage information in the inner layer of the steelmaking slag S and transmit the measured current information and voltage information to the control device 13. Furthermore, the control device 13 may calculate the resistivity value of the inner layer of the steelmaking slag S based on the received current information and voltage information.

[0036] Furthermore, the current electrode A and the potential electrode V may start measuring current information and voltage information in the inner layer of the steelmaking slag S at the same time as the supply of moisture from the moisture supply device 12 to the steelmaking slag S begins, and may continue to periodically measure the current information and voltage information and transmit it to the control device 13. The control device 13 may then continue to periodically calculate the resistivity value in the inner layer of the steelmaking slag S based on the current information and voltage information it receives periodically.

[0037] Measurement of current information and voltage information in the inner layer of steelmaking slag S, or calculation of the resistivity value in the inner layer of steelmaking slag S, is preferably carried out periodically at time intervals of less than one hour in order to capture changes in the resistivity value over time, and more preferably every 10 minutes.

[0038] In the progress determination step, the control device 13 may determine the progress of the aging treatment based on the resistivity value calculated in the resistivity value calculation step. Specifically, the control device 13 may determine, based on the comparison result between the calculated resistivity value and a preset threshold value, whether the water penetration state of the steelmaking slag S that is the target of the aging treatment has become sufficient or insufficient, taking into account past operating results.

[0039] The predetermined threshold value may be set as an index based on past operational results to determine that the water penetration state in the steelmaking slag S is sufficient and that the aging treatment can be terminated during the aging treatment of the steelmaking slag S. The predetermined threshold value may be stored in the memory device 14. In the progress determination process, the control device 13 may read out the predetermined and stored threshold value from the memory device 14 and perform processing. The resistivity value calculated in the resistivity value calculation process is useful as information that is affected by the distribution state of the substance (moisture) contained in the steelmaking slag S, and therefore the progress of the aging treatment can be easily grasped based on the calculated resistivity value.

[0040] Alternatively, in the progress status determination step, the control device 13 may estimate the amount of permeated water in the steelmaking slag S based on the correspondence relationship between the resistivity value calculated in the resistivity value calculation step and the amount of permeated water in the steelmaking slag S. Specifically, the control device 13 may estimate the amount of permeated water in the inner layer of the steelmaking slag S based on correspondence information indicating the correspondence relationship between the resistivity value and the amount of permeated water in the inner layer of the steelmaking slag S (a value indicating the permeation status of water in the inner layer of the steelmaking slag S). In this case, the correspondence information between the resistivity value and the amount of permeated water may be stored in advance in the storage device 14. In the permeated water amount estimation step, the control device 13 may read out the correspondence information between the resistivity value and the amount of permeated water from the storage device 14 and perform processing.

[0041] In the progress status determination step, the control device 13 may perform a control step of controlling the moisture supply device or determine the end of the aging treatment when the resistivity calculated in the resistivity value calculation step becomes a value less than a predetermined threshold value. Specifically, the control device 13 may send a control signal to the moisture supply device 12 to reduce the rate at which moisture is supplied to the steelmaking slag S. Alternatively, in the progress status determination step, the control device 13 may determine the end of the aging treatment based on the resistivity value calculated in the resistivity value calculation step becoming less than 700 Ω·m. The "end" of the aging treatment means the cessation of the supply of moisture to the steelmaking slag S.

[0042] When the supply of moisture to the lower layer SB of the stacked steelmaking slag S begins, moisture penetrates from the lower layer SB to the middle layer SM and upper layer ST in order. When moisture penetrates into the middle layer SM of the steelmaking slag S, the resistivity calculated from the measurements taken by the pair of current electrodes A and the pair of potential electrodes V becomes less than 700 Ω·m. Therefore, the resistivity of the inner layer of the steelmaking slag S becomes less than 700 Ω·m. When the resistivity becomes less than 700 Ω·m, the control device 13 may determine the end of the aging treatment in the progress determination step. This makes it possible to improve the quality of the slag material after the aging treatment (specifically, to reduce the expansion rate in a water immersion expansion test).

[0043] In the progress status determination step, when the resistivity calculated in the resistivity calculation step is equal to or greater than a preset threshold, the control device 13 may perform a control step of controlling the moisture supply device or an additional processing time calculation step of calculating the additional processing time required for the aging treatment. Specifically, the control device 13 may send a control signal to the moisture supply device 12 to increase the supply rate of moisture to the steelmaking slag S. Alternatively, the control device 13 may calculate the additional processing time required for the aging treatment based on the difference between the calculated resistivity value and a preset threshold.

[0044] That is, the steelmaking slag aging treatment method according to the present invention may further include, after the progress status determination process, an additional treatment time calculation process for calculating the additional treatment time required for the aging treatment or a control process for controlling the moisture supply device.

[0045] Furthermore, slag material may be produced using the above-described steelmaking slag aging method according to the present invention. That is, as a method for producing slag material, the steelmaking slag aging method according to the present invention may be used to produce slag material of improved quality that can be used as roadbed material or coarse aggregate for concrete. In this case, the slag material produced using the steelmaking slag aging method according to the present invention preferably has a resistivity measured after treatment of less than 700 Ω·m.

[0046] As described above, the control device 13 may determine the end of the aging treatment when the calculated resistivity is less than 700 Ω·m. The effective resistivity for the water penetration state in the inner layer of the steelmaking slag S is preferably 500 Ω·m or less, and more preferably 200 Ω·m or less, instead of less than 700 Ω·m. This makes it possible to further improve the quality of the slag material after the aging treatment (specifically, to reduce the expansion rate in a water immersion expansion test).

[0047] As mentioned above, by providing an electrode configuration that combines a pair of current electrodes A and a pair of potential electrodes V at multiple locations on the surface of the outer layer of the steelmaking slag S, it is possible to grasp the two-dimensional or three-dimensional distribution of the progress of the aging treatment in the inner layer of the steelmaking slag S.

[0048] In this case, the resistivity value based on the actual measurement value calculated from the information (current information and voltage information) measured at each position may be corrected based on the resistivity values ​​at multiple locations. Specifically, the resistivity value calculated for each position in the inner layer of the steelmaking slag S is a local value that does not take into account the surrounding conditions of each position being measured. Therefore, if the steelmaking slag S contains impurities, the resistivity value based on the actual measurement value will show an extreme value. On the other hand, since the moisture that penetrates the inner layer of the steelmaking slag S has linearity in two and three dimensions, it is not preferable to directly apply the resistivity value based on the actual measurement value in order to accurately grasp the progress of the aging treatment.

[0049] Therefore, in order to accurately grasp the two-dimensional or three-dimensional distribution of the progress of the aging treatment in the inner layer of steelmaking slag S, it is possible to perform an approximation process (inverse analysis) using multiple resistivity values ​​collected in two or three dimensions, thereby correcting the resistivity values ​​based on the actual measured values ​​at individual positions.

[0050] From the above, when grasping the two-dimensional or three-dimensional distribution of the progress of the aging treatment in the inner layer of the steelmaking slag S, the resistivity calculation step may involve calculating the resistivity based on the actual measured value and correcting the resistivity based on the calculated actual measured value. The end of the aging treatment may then be determined based on the corrected resistivity being less than 700 Ω·m. Furthermore, instead of the corrected resistivity being less than 700 Ω·m, it is preferable to set the corrected resistivity to 500 Ω·m or less, and even more preferably 200 Ω·m or less. This makes it possible to further improve the quality of the slag material after the aging treatment (specifically, to reduce the expansion rate in a water immersion expansion test). [Example]

[0051] Next, we will explain the results of aging treatment of steelmaking slag using the steelmaking slag aging treatment method according to the present invention. The examples were conducted for various types of steelmaking slag, with 10 to 10,000 tons of steelmaking slag stacked to a height of 1 to 3 m in the aging treatment plant shown in Figure 2. The width of the stacked steelmaking slag was 20 m, and the depth was 10 m.

[0052] Water was supplied to the steelmaking slag in the form of a water flow, steam, or pressurized steam. The water supply rate was set at 0.0 to 20.0 t / h upon the start of the aging treatment of the steelmaking slag. Furthermore, for each example, the electrode configuration, which involved a combination of a pair of current electrodes and a pair of potential electrodes, was installed at any of the following positions on the top, side, or bottom of the loaded steelmaking slag: a range from the top to the side, a range from the side to the bottom, or a range including the top and side. The distance between the pair of current electrodes and the pair of potential electrodes installed on the surface of the steelmaking slag was set to 1 to 4 m, and the resistivity was calculated. The distance between the pair of current electrodes and the pair of potential electrodes installed on the surface of the steelmaking slag was the same as the distance between the pair of current electrodes and the pair of potential electrodes. The current and voltage information used to calculate the resistivity was measured at time intervals of 5 to 120 min.

[0053] In the examples, the water supply rate supplied to the steelmaking slag at the start of the aging treatment ("water supply rate" in Table 1) was confirmed. Also confirmed were the "minimum resistivity value Ω·m," which is the minimum resistivity value calculated during the aging treatment, the total treatment time required for the aging treatment, and the water supply rate changed after calculating the resistivity value (minimum resistivity value) ("changed water supply rate" in Table 1). The "total treatment time" was defined as the predetermined treatment time in each example, or, when an additional treatment time was calculated, the total time of the predetermined treatment time and the additional treatment time.

[0054] Furthermore, after the aging treatment, the "resistivity measurement value after treatment Ω·m" was measured on the slag material after the aging treatment, and the "quality of the slag material after treatment" was also confirmed. The "quality of the slag material after treatment" was confirmed based on the water immersion expansion test in "JIS A 5015:2018 Iron and steel slag for road use." The "quality of the slag material after treatment" was evaluated as "Good" if the expansion rate was 1% or less, and as "Poor" if the expansion rate exceeded 1%. The results of the examples are shown in Table 1.

[0055] [Table 1]

[0056] In Comparative Example 1, a pair of current electrodes and a pair of potential electrodes were installed on the upper surface of the steelmaking slag, and the distance between the electrodes ("electrode placement distance" in Table 1) was set to 4 m. As a result, the position of the electric field formed in the depth direction of the inner layer of the steelmaking slag was deeper than the thickness of the steelmaking slag, and therefore an accurate resistivity value could not be calculated.

[0057] In Comparative Example 2, the water supplied to the steelmaking slag was set to a water flow, but water was not actually supplied, so the aging treatment of the steelmaking slag did not progress. That is, the minimum resistivity reached was the same as the resistivity value of the steelmaking slag at the start of the aging treatment (2000 Ω m), confirming that water penetration into the inner layer of the steelmaking slag did not progress.

[0058] In Examples 1 to 18 of the present invention, calculation of the resistivity value of the steelmaking slag was started when the supply of water to the steelmaking slag began, and the resistivity value was continued to be calculated periodically, making it possible to easily grasp the progress of the aging treatment in the inner layer of the steelmaking slag.

[0059] In addition, in Examples 1 to 10 and 14 to 18, the "minimum resistivity value Ω·m" during the aging treatment was less than 700 Ω·m, and the "measured resistivity value Ω·m after treatment" was also less than 700 Ω·m after the aging treatment, so the "quality of slag material after treatment" was evaluated as "Good."

[0060] From the above, it has been confirmed that the slag aging treatment method of the present invention makes it possible to easily grasp the progress of the aging treatment in the inner layer of stacked steelmaking slag without the need to install and recover measuring equipment in the inner layer. [Explanation of symbols]

[0061] 11 Aging Treatment Plant 12 Moisture supply device 13 Control device 14 Storage device 20 Progress Determination Device A current electrode V potential electrode S Steelmaking slag C midpoint D distance N measurement points ST upper layer SM middle class SB lower layer

Claims

1. A method for aging steelmaking slag, comprising: a moisture supply starting step of starting the supply of moisture from the moisture supply device to the steelmaking slag; a resistivity calculation step of calculating the resistivity of the steelmaking slag using a current electrode and a potential electrode installed on the surface of the steelmaking slag; a progress status determination step of determining a progress status of the aging treatment based on the resistivity value calculated in the resistivity value calculation step; A method for aging steelmaking slag, comprising:

2. The steelmaking slag aging treatment method according to claim 1, wherein the progress status determination process determines the end of the aging treatment based on the resistivity value calculated by the resistivity value calculation process becoming less than a threshold value.

3. The method for aging steelmaking slag according to claim 2, wherein the threshold value is 700 Ω·m.

4. The steelmaking slag aging treatment method according to claim 1, further comprising, after the progress status determination process, an additional treatment time calculation process for calculating the additional treatment time required for the aging treatment or a control process for controlling the moisture supply device.

5. A method for producing a slag material, comprising producing the slag material by the steelmaking slag aging treatment method according to any one of claims 1 to 4.

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