JP2006169089A - Slag processing method, processing apparatus and lance - Google Patents

Abstract

【Task】
Provided is a means capable of uniformly heating and modifying the entire molten slag while suppressing the generation of CO gas bubbles as much as possible.
[Solution]
An apparatus 1 for heating and processing molten slag a placed in a slag pan 2, comprising a burner 3 for heating the molten slag a and a lance 4 for injecting gas in the molten slag a. 4, the injection ports 10 for injecting gas in the horizontal direction in the molten slag a are provided at a plurality of locations, and each of the injection ports 10 gives a swirl flow to the molten slag a around the lance 4. They are oriented in the same turning direction. The molten slag a placed in the slag pan 2 is allowed to stand for a predetermined time, and then the step of heating the molten slag a and the step of stirring the molten slag a are alternately performed once or a plurality of times.
[Selection] Figure 4

Description

  The present invention relates to a method, an apparatus, and a lance for reforming slag generated in a steelmaking process or the like in a molten state.

  Slag (steel slag) generated by dephosphorization, desulfurization, and decarburization refining is used for road roadbed materials, concrete aggregates, and the like. However, free CaO contained in steelmaking slag is low in volume stability because it expands due to a hydration reaction, and steelmaking slag is used for low-grade applications such as temporary materials for civil engineering, road improvement materials, and lower roadbed materials. It is used exclusively, and it is difficult to use it for higher-grade roadbed materials, concrete aggregates, stone materials, etc.

  For this reason, a method of promoting the hydration reaction of free CaO in slag by natural curing or steam aging is generally employed. However, in order to perform natural curing and steam aging in this way, long-term curing and a large site are required until the expansion characteristics can be ignored. In this method, free CaO cannot be effectively eliminated, and the use of slag is still limited.

  Therefore, conventionally, a method for reforming decarburized slag discharged from a converter in a molten state has been disclosed (see Non-Patent Document 1). This is because oxygen and silica are blown into the molten slag through a dipping lance, the FeO in the slag is oxidized and heated to reduce the basicity of the slag by the modifier, and the unstabilized lime is a volume-stable compound. It is a method to change to. Similarly, a method of reducing the basicity of the slag with the modifier while blowing the modifier and the temperature raising material from the immersion lance into the molten slag and heating the slag is also disclosed (see Patent Document 1). . In addition, a method of charging a component adjusting agent into molten slag stored in an electric furnace and gas bubbling is also disclosed (see Patent Document 2). And as a shape of a lance, the structure which blows off gas horizontally with two holes centering on a lance is also disclosed (refer patent document 3). In addition, a method of bubbling gas from the bottom of a ladle containing molten steel is also disclosed (see Patent Document 4).

M. Kuehn, et al., 2nd European Steelmaking Congress, Taranto (1997) p445 / 453 JP-A-2-204348 JP-A-8-175853 JP-A-9-125130 Japanese Patent Laid-Open No. 2003-222212

As described in Non-Patent Document 1 and Patent Documents 1 to 4, conventionally, the entire molten slag contained in the slag pan is heated by blowing gas from the lance and stirring the molten slag, and uniform modification. It is known that quality can be done. However, the granular iron is suspended in the molten slag immediately after being discharged from the converter and placed in the slag pan, and the carbon present on the surface of the suspended granular iron reacts with the iron oxide in the molten slag. As a result, CO gas bubbles are generated in the molten slag.
The generation of such CO gas gradually subsides as the granular iron settles down to the bottom of the slag pan with its own weight over time, but the molten slag was stirred by blowing gas from the lance as in the conventional method described above. In such a case, the smooth sedimentation of the granular iron is hindered, and the generation of CO gas bubbles is difficult. In addition, conventionally, there is a concern that the granular iron once settled at the bottom of the slag pan is lifted up again by gas blowing and suspended in the molten slag, and the generation of CO gas bubbles is further prolonged. It was. As described above, in terms of uniform reforming, it is preferable to stir the molten slag by blowing out gas as in the conventional method. However, in this case, there is a problem in that the generation of CO gas bubbles does not easily occur.

  An object of the present invention is to provide means capable of uniformly heating and modifying the entire molten slag while suppressing the generation of CO gas bubbles as much as possible.

  In order to solve such a problem, according to the present invention, the molten slag placed in the slag pan is allowed to stand for a predetermined time, and then the step of heating the molten slag and the step of stirring the molten slag are alternately performed once. There is provided a method for treating slag, which is characterized in that it is performed one by one or a plurality of times.

  In the step of heating the molten slag, a modifier that lowers the basicity of the slag may be sprayed onto the molten slag. In the step of stirring the molten slag, the molten slag may be swirled by a gas injected from a lance inserted into the slag pan.

  Alternatively, the molten slag treated by the above treatment method may be poured onto a rotating drum provided with a plurality of blades, and the slag may be granulated by cooling with sprinkling while scattering the slag.

  According to the present invention, there is provided an apparatus for heating and processing molten slag placed in a slag pan, comprising a burner for heating the molten slag, and a lance for injecting gas in the molten slag. Are provided with a plurality of injection ports for injecting gas in the horizontal direction in the molten slag, and each injection port is directed in the same swirling direction so as to give a swirling flow to the molten slag around the lance. An apparatus for treating slag is provided.

  The lance may have a cylindrical shape, and each injection port may be inclined in the same direction with respect to the radius of the lance. In addition, the injection ports may be arranged at the same height. Furthermore, the burner may be capable of spraying a modifier that reduces the basicity of the slag.

  According to the present invention, there is provided a lance for injecting gas into molten metal or molten slag, and the injection ports for injecting gas are provided at a plurality of locations, and each injection port is centered on the lance. A lance is provided, characterized by being directed in the same swirl direction so as to impart a swirl flow to the molten metal or molten slag.

  According to the present invention, the molten slag can be efficiently heated by heating the molten slag in a state where it is difficult for bubbles to be generated by allowing the granular iron to settle to the bottom of the slag pan, and the molten slag can be efficiently heated. It becomes possible to effectively reduce free CaO contained in the slag. In addition, when producing granular slag, it is also possible to separate the granular iron. When stirring the molten slag, the molten iron is swirled around the lance so that the granular iron that has previously settled at the bottom of the slag pan is allowed to settle at the bottom of the slag pan without being suspended again in the molten slag. The molten slag can be agitated while maintaining the maintained state. For this reason, generation | occurrence | production of the bubble of CO gas is suppressed. In addition, granular iron can be separated from slag with high accuracy, and slag can be improved and quality can be improved.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a processing apparatus 1 according to an embodiment of the present invention. 2 is a partially enlarged longitudinal sectional view (YY sectional view in FIG. 3) of the lower end portion of the lance 4 provided in the processing apparatus 1, and FIG. It is XX sectional drawing in FIG. FIG. 4 is a process explanatory diagram of the processing method of the molten slag a according to the embodiment of the present invention.

  As shown in FIG. 1, the slag pan 2 is a substantially cylindrical container having an open top surface and a closed bottom surface. As will be described later, for example, molten slag (hot metal preliminary treatment slag) a discharged from the steel making process is put in the slag pan 2 in a molten state.

  Above the slag pan 2, a burner 3 for heating the molten slag a put in the slag pan 2 and a lance 4 for stirring the molten slag a are arranged. The burner 3 and the lance 4 are supported by respective moving mechanisms (not shown). Thereby, the burner 3 is moved from the liquid level of the molten slag a put in the slag pan 2 to a position at a predetermined height. On the other hand, the lance 4 is movable to a position where the injection port 10 at the tip of the lance 4 is immersed in the liquid of the molten slag a put in the slag pan 2.

  The burner 3 irradiates a flame toward the molten slag a placed in the slag pan 2 using, for example, LPG, heavy oil, pulverized coal, waste plastic, or the like as fuel. In addition, the burner 3 can spray the flame so as to heat the molten slag a and to spray a modifier for reducing the basicity of the slag toward the liquid surface of the molten slag a as necessary. It has become.

  As shown in FIGS. 2 and 3, the lance 4 is composed of a cylindrical lance body 5 whose bottom surface is closed, and a refractory 6 covering the outer and lower surfaces of the lance body 5. Is also formed in a cylindrical shape. The lance body 5 is made of steel, for example. At the lower end of the lance 4, there are provided a plurality of injection ports 10 that open to the outer peripheral surface. In the illustrated example, four injection ports 10 are opened on the outer peripheral surface of the lower end portion of the lance 4, and each injection port 10 has a central angle of 90 ° C. with respect to the central axis O (vertical direction) of the lance 4. They are arranged at intervals. In addition, these injection ports 10 are arranged at the same height.

  Each injection port 10 is connected to a communication passage 12 communicating with an internal space 11 of the lance 4 (an internal space of the lance main body 5) 11. Each communication passage 12 is provided so as to communicate at the same height as each injection port 10.

  The communication passage 12 includes a communication passage inner portion 15 that directly communicates with the inner space 11 of the lance 4 and a communication passage outer portion 16 that directly communicates with the injection port 10. The communication passage inner portion 15 extends from the central axis O of the lance 4. The lance 4 is oriented in a direction along the radius r of the lance 4 that extends radially. On the other hand, the communication passage outer portion 16 directly communicating with the injection port 10 on the outer peripheral surface of the lance 4 is inclined at an angle α in the clockwise direction with respect to the radius r of the lance 4 when viewed from above. Is provided. As a result, when gas is pressed into the internal space 11 of the lance 4 as will be described later, the gas is blown out from the injection port 10 toward the outside of the lance 4 and into the horizontal plane. A swirling flow in the clockwise direction (in a state viewed from above) is generated around the lance 4 with respect to the molten slag a.

  Now, in the processing apparatus 1 configured as described above, for example, the molten slag a discharged from the converter is put into the slag pan 2 in a molten state. When the molten slag a is put into the slag pan 2 in this way, the burner 3 and the lance 4 are retracted to a position that does not interfere with the work by respective moving mechanisms (not shown).

  As shown in FIG. 4 (a), the granular iron 20 is still suspended in the molten slag a immediately after being put in the slag pan 2, and the carbon adhering to the surface of the suspended granular iron 20 and By reacting the iron oxide contained in the molten slag a, CO gas bubbles 21 are generated in the molten slag a. In addition, when molten slag a is put into the slag pan 2 in this way, the molten slag a contacts the inner surface of the slag pan 2 and is partially cooled and solidified so that the inner surface of the slag pan 2 is aligned. , A solidified layer 22 of slag is formed.

  First, immediately after being discharged from the converter or the like and placed in the slag pan 2, the molten slag a is allowed to stand for a predetermined time, and the granular iron 20 suspended in the molten slag a is shown in FIG. As shown in b), the slag pan 2 is sufficiently settled at the bottom. In this case, the time for standing still is determined by the settling speed of the granular iron 20 and the depth of the molten pool (depth of the molten slag a). In other words, the standing time should be longer than the value obtained by dividing the molten pool depth by the settling velocity. The settling velocity is governed by the Stokes equation and is determined by the size of the granular iron 20 and the viscosity of the molten slag a. For example, when the settling rate of the granular iron 20 having a particle size of 1.0 mm with a viscosity of 1.43 Pa · s (assuming a foam slag containing 67% of bubbles by volume) is 2.21 mm / sec, the molten pool depth Assuming that the thickness is 1000 mm, all of the granular iron 20 having a particle diameter of 1 mm or more will settle if left standing for 452 sec (about 7.5 minutes) or more. Here, granular iron 20 having a particle size of 1.0 mm or more was targeted because it takes too much time to settle if the particle size is less than 1.0 mm, and it is not practical or used as an iron raw material even if it is precipitated. That is why it is difficult to do. The depth of the molten pool of 1000 mm is due to the fact that this height is used as a guideline because it is almost the minimum height in actual operation. Therefore, when the molten pool depth is large, it is important to set the standing time longer. Actually, the sedimentation efficiency is worse than the above estimation due to the flow of slag caused by foaming. Therefore, it is desirable to leave it as a guide for a time that is at least twice the estimated time. In addition, while the granular iron 20 is settling in this way, the bubbles 21 existing in the molten slag a are floated and discharged, so that the liquid surface height of the molten slag a gradually decreases.

  After the granular iron 20 is sufficiently settled in the bottom of the slag pan 2 in this manner, a step of heating the molten slag a is performed. That is, first, the burner 3 is moved from the liquid surface of the molten slag a placed in the slag pan 2 to a predetermined height by a moving mechanism (not shown). In this case, it is preferable that the position where the temperature of the flame 25 ejected from the jet outlet at the lower end of the burner 3 becomes the highest is near the liquid surface of the molten slag a. Next, as shown in FIG. 4 (c), the flame 25 is ejected downward from the burner 3 toward the liquid surface of the molten slag a to heat the molten slag a. As a result, a high temperature region a 'of the molten slag a is gradually formed near the liquid surface of the molten slag a. In this case, as described above, the bubbles 21 mixed in the molten slag a in the process of allowing the granular iron 20 to settle to the bottom of the slag pan 2 are levitated and discharged, and the bubbles in which the granular iron 20 is settled are not easily generated. Since the molten slag a is heated, the heat transfer efficiency can be improved and the molten slag a can be efficiently heated to the inside.

Further, in the step of heating the molten slag a in this way, a modifier that lowers the basicity of the slag may be sprayed from the burner 3 toward the molten slag a. The modifying material is not particularly limited as long as the basicity (CaO / SiO ₂ (mass ratio)) is lower than that of the molten slag a, but for example, a material containing SiO ₂ may be sprayed. Examples of the substance containing SiO ₂ include fly ash and silica sand. The amount of spraying of the reforming material may be appropriately set based on the component and temperature of the molten slag a, the target component of the reforming slag, and the like.

  Thus, after the high temperature region a 'is formed near the liquid surface of the molten slag a, the burner 3 is retracted. Next, the lance 4 is moved by a moving mechanism (not shown), the lance 4 is inserted in the approximate center of the slag pan 2 as shown in FIG. 4 (d), and the injection port 10 of the molten slag a placed in the slag pan 2 It is made into the state immersed in the liquid. Then, a gas such as air, oxygen, or nitrogen is pressed into the internal space 11 of the lance 4, and the gas 26 is injected into the molten slag a from the injection port 10 opened at the outer peripheral surface of the lower end portion of the lance 4.

  Thus, when the gas 26 is injected from the plurality of injection ports 10 toward the outside of the lance 4 in the molten slag a, the lance 4 is centered with respect to the molten slag a as described in FIGS. A swirling flow in the clockwise direction is given. Thus, the molten slag a in the slag pan 2 is stirred as a whole while turning clockwise around the lance 4.

By stirring the molten slag a in the slag pan 2 in this manner, the temperature of the molten slag a can be made uniform to improve the fluidity, and the rising and discharging of bubbles from the molten slag a can be promoted. At the same time, the free CaO present in the molten slag a is reacted with SiO ₂ or the like contained in the molten slag a or the sprayed modifier to change into a volume-stable compound (2CaO · SiO ₂ or the like). And uniform modification can be applied to the entire molten slag a. In addition, when oxygen is blown into the molten slag a from the injection port 10 of the lance 4, FeO in the molten slag a is oxidized, and the fluidity of the molten slag a is improved by the oxidation heat generated at that time. As a result, melt reforming can be further promoted.

  Thus, the heating operation by the burner 3 and the stirring operation by the lance 4 or the heating operation by the burner 3 and the spraying operation of the modifying material and the stirring operation by the lance 4 are alternately performed once or plural times as appropriate, After removing the bubbles and modifying the molten slag a, the slag pan 2 is tilted and the modified molten slag a is discharged into the pan 30 as shown in FIG. In this case, it is advisable to take care not to let the granular iron 20 settled on the bottom of the slag pan 2 flow out to the pan 30 by appropriately adjusting the tilt angle of the slag pan 2 and the speed at which the slag pan 2 is tilted. In addition, although the solidified layer 22 of slag is formed along the inner surface of the slag pan 2 as described above, when the granular iron 20 settled on the bottom of the slag pan 2 is fixed in the solidified layer 22, Even if the slag pan 2 is tilted and the angle is slightly increased, there is no fear that the granular iron 20 will flow into the ladle 30.

In addition, in FIG.4 (e), although the case where the molten slag obtained by the melt-modification process was discharged to the pan 30 and a slag lump was produced was explained, sand or fine aggregate is produced directly from the slag. After performing the steps described in FIGS. 4C and 4D, as shown in FIG. 5, the slag pan 2 is tilted and the molten slag a in the slag pan 2 is installed with a plurality of blades. It is preferable to inject it onto the rotating drum 40 that is rotating at a high speed (usually a drum peripheral speed; about 1 to 30 m / second) to scatter the slag in granular form. Then, the cooling water sprayed from the watering nozzle 41 is brought into contact with the scattered slag and solidified by cooling (usually cooling water amount / slag mass; about 0.2 to 3.0 m ³ / ton · slag). , Granulated slag can be obtained. The granular slag obtained in this way can be used as sand and fine aggregate such as roadbed material and aggregate for concrete.

  In this case, as shown in FIG. 5, a plurality of buckets 42 are arranged side by side according to the distance from the rotating drum 40, and granular slag scattered by the rotation of the rotating drum 40 is separated for each scattering position (scattering distance). You may divide and collect in each bucket 42. In the state after performing the steps described in FIGS. 4C and 4D, the molten slag a still contains some granular iron, but the slag is granular by the rotation of the rotating drum 40 in this way. It is possible to easily separate the granular slag from the granular iron by collecting the granular slag by classifying each of the scattering positions and collecting the granular slag.

  That is, according to the knowledge of the present inventors, when the slag dispersed in a granular form by the rotation of the rotating drum 40 is classified and collected for each scattering position, as shown in FIG. 6, the scattering distance (slag collecting position) It was found that the larger the (L)), the smaller the iron content, and the smaller the scattering distance, the higher the iron content. In FIG. 6, the slag collection position (L) on the horizontal axis indicates the scattering distance of the particulate slag from the rotating drum as L = 1, and the scattering distance of the particulate slag is shown as a relative value. Moreover, the granular iron ratio of the vertical axis | shaft has shown the mass ratio (%) of the granular iron of the particulate slag collect | recovered in each bucket 42 according to each scattering distance. From FIG. 6, by selecting the collection position, it is possible to obtain particulate slag that does not contain granular iron even if magnetic separation is not performed. It is understood that the separation and recovery of granular iron can be efficiently performed.

  According to the embodiment of the present invention described above, in the step of stirring the molten slag a, the molten slag a is swiveled around the lance 4 inserted in the approximate center of the slag pan 2, so that the slag pan 2 The molten slag a can be agitated while maintaining the state of sedimentation at the bottom of the slag pan 2 without raising the granular iron 20 settled at the bottom of the slag. For this reason, it is possible to remove the bubbles and modify the molten slag a while suppressing the generation of bubbles of the CO gas. In addition, since the granular iron can be separated from the slag with high accuracy, the quality of the slag can be improved. The slag thus modified has a reduced water immersion expansion ratio and improved strength. For this reason, the treated slag is useful in various ways such as upper roadbed materials, asphalt mixed road materials, asphalt pavement aggregates, concrete aggregates, concrete secondary material materials, ceramics and tile materials, and artificial stone materials. It can be applied to raw materials and can be used effectively as a recycled resource. The granular iron 20 separated from the slag can be used as an iron raw material.

  As mentioned above, although preferred embodiment of this invention was illustrated, this invention is not limited to the form demonstrated here. For example, of course, a swirl flow in the counterclockwise direction may be generated and stirred in the molten slag a placed in the slag pan 2 in a state viewed from above. Further, the heating operation by the burner 3 and the stirring operation by the lance 4, or the heating operation by the burner 3 and the spraying operation of the modifying material and the stirring operation by the lance 4 may be alternately performed once or a plurality of times. It may be repeated alternately.

  The injection port 10 provided in the lance 4 should just exist in several places, and does not necessarily need to be four places. The gas directed in the same swirling direction may be ejected from the injection ports 10 provided at a plurality of locations so as to generate a swirling flow in the molten slag a around the lance 4. Further, the height of each injection port 10 does not necessarily have to be the same, and gas is ejected from a plurality of injection ports 10 at different heights so that the molten slag a is turned around the lance 4. Also good. Further, the lance 4 may be moved up and down during stirring. The gas blown from the lance 4 into the molten slag a may be at room temperature, but if a high temperature gas is used, the molten slag a can be prevented from being cooled. Further, instead of the lance 4, the molten slag a may be mechanically stirred using, for example, a stirring blade. The lance 4 described above can also be applied to other fluids (fluids other than slag) that require a horizontal swirling flow.

Example 1
1-3, the hot metal pretreatment slag 20 ton from the steelmaking process (23% by mass of grain iron with a diameter of 1 mm or more before the reforming treatment) is discharged into a slag pan and left for 15 minutes. did. Then, while heating the molten slag (hot metal pretreatment slag) with a burner, spraying fly ash as a reforming material at a speed of 6400 kg / h for 5 minutes, immediately immersing the lance in the molten slag and gas ( Air) was blown at 600 Nm ³ / h, and the molten slag was rotated around the lance and stirred. The bubbling time (stirring time) is 1 minute. Thus, heating with a burner for 5 minutes, spraying of fly ash, and gas stirring with a lance for 1 minute were repeated three times alternately. After that, the slag pan was tilted and the modified molten slag was discharged. As a result of conducting magnetic separation after pulverizing the discharged slag, it was found that the amount of granular iron having a diameter of 1 mm or more was less than 1% by mass, and the separation of the granular iron was good by the modification treatment. The foaming phenomenon did not occur in any of the heating and thermal spraying steps and the stirring step, and the obtained slag had a water absorption of 1.0% by mass and could be used sufficiently as an aggregate.

(Example 2)
1-3, the hot metal pretreatment slag 20 ton from the steelmaking process (24% by mass of the grain iron with a diameter of 1 mm or more before the reforming treatment) is discharged into the slag pan, and the standing time is reduced. An attempt was made to make the evaluation in a state where granular iron was suspended in the slag. After allowing the slag to stand for 5 minutes (the amount of granular iron having a diameter of 1 mm or more is 20% by mass), the fly ash is heated at a rate of 6400 kg / h as a modifier while heating the molten slag (hot metal pretreatment slag) with a burner. After spraying for 5 minutes, the lance was immediately immersed in the molten slag and gas (air) was blown horizontally at 600 Nm ³ / h, and the molten slag was rotated around the lance and stirred. The bubbling time (stirring time) is 1 minute. Thus, heating with a burner for 5 minutes, spraying of fly ash, and gas stirring with a lance for 1 minute were alternately repeated 5 times. In order to produce fine aggregate, a rotating drum that tilts the slag pan and rotates the modified molten slag suspended in granular iron with a plurality of blades and rotates at high speed (drum peripheral speed: 1 to 15 m / sec) Sprinkling cooling (cooling water amount / slag mass; 2.0 m ³ / ton · slag) was performed while sprinkling slag to produce granular slag. In some cases, a foaming phenomenon occurred slightly in both the heating and spraying steps and the stirring step.
The slag that has been granulated can be easily removed by magnetic separation from the slag collected at L = 0 to less than 0.6, which is close to the rotating drum, and the obtained particulate slag The water absorption was 0.90% by mass. On the other hand, the content of granular iron collected at a position of L = 0.6 to 1.0 far from the rotating drum is less than 1% by mass, which is a problem-free level (L = 0.8 to 1.0 is very small). The water absorption of the particulate slag was 0.85% by mass. Therefore, both can be used satisfactorily as sand and fine aggregates. Even under conditions where the sedation time is short and the amount of suspended iron is relatively large, the slag can be easily treated with granular iron. Separation was possible.

(Example 3)
1-3, the hot metal pretreatment slag 20 ton from the steel making process (25% by mass of the grain iron with a diameter of 1 mm or more before the reforming treatment is 25% by mass) is discharged into the slag pan and left for 15 minutes. did. Then, while heating the molten slag (hot metal pretreatment slag) with a burner, spraying fly ash as a reforming material at a speed of 6400 kg / h for 5 minutes, immediately immersing the lance in the molten slag and gas ( Air) was blown at 600 Nm ³ / h, and the molten slag was rotated around the lance and stirred. The bubbling time (stirring time) is 1 minute. Thus, heating with a burner for 5 minutes, spraying of fly ash, and gas stirring with a lance for 1 minute were alternately repeated 5 times.
Here, for the purpose of evaluating the effect of rewinding the granular iron during operation, the lance immersion depth was increased by the last gas agitation, and the granular iron settled on the bottom of the slag pan was rewinded and again Rotating drum that rotates the slag pan, which has been suspended, and rotates at a high speed (drum peripheral speed: 1 to 15 m / sec) by tilting the slag pan and setting the plurality of blades without causing the granular iron to settle Sprinkling cooling (cooling water amount / slag mass; 2.0 m ³ / ton · slag) was performed while sprinkling slag to produce granular slag. No foaming phenomenon occurred in either the heating and thermal spraying steps or the stirring step, but a slight slag foaming phenomenon was observed after resuspending the granular iron.
Granular iron can be easily removed by magnetic separation from the slag collected at L = 0 to less than 0.6, which is close to the rotating drum, where the granular slag is collected, and the obtained granular slag has a water absorption rate of 1.0. It was mass%. On the other hand, the content of granular iron having a diameter of 1 mm or more collected at a position of L = 0.6 to 1.0 far from the rotating drum is less than 1% and is a level without any problem (at L = 0.8 to 1.0). Slightly), the water absorption of the particulate slag was 0.95% by mass. Therefore, both could be used as sand and fine aggregate.

(Comparative example)
Using the same equipment as in the above example, the molten iron pretreatment slag 20ton from the steelmaking process was discharged into the slag pan, and the molten slag was immediately removed with a burner. While heating, fly ash was sprayed as a modifier at a rate of 6400 kg / h for 5 minutes, and then air was bubbled downward from a single tube lance immersed in the molten slag for 1 minute at 600 Nm ³ / h for molten slag. Was stirred. Thus, heating with a burner for 5 minutes, spraying of fly ash, and stirring with a single pipe lance were repeated three times alternately. After that, the slag pan was tilted and the modified molten slag was discharged.
In both the heating and thermal spraying steps and the stirring step, a severe foaming phenomenon occurred continuously, and the treatment was suspended until the foaming phenomenon subsided. The discharged slag was a slag that was easy to collapse, as many bubbles and granular iron could be visually confirmed. Moreover, the water absorption rate of the slag was 7.3% by mass.
After the modified slag was cooled, the slag was pulverized, and then the magnetic iron was collected to collect the granular iron. As a result, 3400 kg of granular iron with a diameter of more than 1 mm was obtained, and about 85 of the 4000 kg of granular iron that existed before the treatment. % Remained in the modified slag. Therefore, it was found that the granular iron was not sufficiently separated during the reforming process.

  The present invention is used for the treatment of slag generated in a steel making process or the like.

It is explanatory drawing which shows schematic structure of the processing apparatus concerning embodiment of this invention. It is a partial expanded longitudinal cross-sectional view in the lower end part of a lance (YY sectional drawing in FIG. 3). It is an expanded horizontal sectional view (XX sectional view in Drawing 2) in the lower end part of a lance. It is process explanatory drawing of the processing method of the molten slag concerning embodiment of this invention. It is a figure which shows a granular slag manufacturing apparatus. It is a figure which shows the relationship between a slag collection | recovery position and the ratio of the granular iron in collection | recovery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Slag pan 3 Burner 4 Lance 5 Lance main body 6 Refractory material 10 Injection port 11 Internal space 12 Communication path 15 Communication path inner side 16 Communication path outer side 20 Grain iron 21 Bubble 22 Slag solidified layer 25 Flame 26 Gas 30 Ladle 40 Rotating drum 41 Sprinkling nozzle 42 Bucket a Molten slag a 'High temperature area r Lance radius

Claims (9)

  The molten slag placed in the slag pan is allowed to stand for a predetermined time, and then the step of heating the molten slag and the step of stirring the molten slag are alternately performed once or multiple times. Processing method.   2. The slag treatment method according to claim 1, wherein in the step of heating the molten slag, a modifier that lowers the basicity of the slag is sprayed on the molten slag. 3.   The method for treating slag according to claim 1 or 2, wherein in the step of stirring the molten slag, the molten slag is swirled by a gas injected from a lance inserted into a slag pan.   By injecting the molten slag treated by the slag treatment method according to any one of claims 1 to 3 onto a rotating drum on which a plurality of blades are installed, and cooling the water while spraying the slag. A method for processing slag, characterized by granulating slag. A device that heats and processes molten slag in a slag pan,
A burner for heating the molten slag;
A lance for injecting gas in the molten slag,
The lance is provided with a plurality of injection ports for injecting gas in the horizontal direction in the molten slag, and each injection port has the same swirl direction so as to give a swirl flow to the molten slag around the lance. Slag processing equipment, characterized by   The slag processing apparatus according to claim 4, wherein the lance has a cylindrical shape, and each injection port is inclined in the same direction with respect to a radius of the lance.   6. The slag processing apparatus according to claim 4, wherein the injection ports are arranged at the same height.   The slag treatment apparatus according to any one of claims 4 to 6, wherein the burner is capable of spraying a modifier that reduces the basicity of the slag.   A lance for injecting gas into the molten metal or molten slag, and there are a plurality of injection ports for injecting gas, and each of the injection ports swivels around the lance to the molten metal or molten slag. A lance characterized by being directed in the same direction of swivel to give flow.

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