JP2020049481A - Magnetic separation method for steel-making slag and magnetic separation apparatus - Google Patents

Abstract

To provide a magnetic separation method for steel-making slag for the purpose of recovering a ferrous compound and a metallic iron from a slurry-like steel-making slag by magnetic separation, in which Fe concentration in the recovery can be increased.SOLUTION: A magnetic separation method for steel-making slag according to the invention includes: a process in which slurry, which contains crushed or pulverized particulate steelmaking slag is injected to a surface of a rotary drum on at least a part of which magnetic field is formed; and a process in which a liquid sprayed to the surface of the rotary drum, thereby removing a liquid component and a non-magnetic matter which rotationally move along the surface of the rotary drum and are contained in the slurry.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetic separation method for a steelmaking slag and a magnetic separation apparatus.

  Steelmaking slag (such as converter slag, pretreatment slag, secondary refining slag, and electric furnace slag) generated in the steelmaking process is used for a wide range of applications including cement materials, roadbed materials, civil engineering materials, and fertilizers. References 1 to 3). In addition, some steelmaking slag not used for the above applications is landfilled.

  The steelmaking slag includes phosphorus (P), calcium (Ca), iron (Fe), silicon (Si), manganese (Mn), magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), It is known that elements such as sulfur (S) are contained. Among these, the element most contained in the steelmaking slag is Ca used in a large amount in the steelmaking process, and usually contains Fe second most. Usually, of the total mass of the steelmaking slag, approximately 20% to 50% by mass is Ca, and approximately 1% to 30% by mass is Fe.

Fe in the steelmaking slag exists as iron-based oxides, calcium iron aluminum oxide (Ca ₂ (Al _1−X Fe _X ) ₂ O ₅ ), and a small amount of metallic iron. Among them, the iron-based oxide contains Mn or Mg and also contains a small amount of elements such as Ca, Al, Si, P, Ti, Cr and S. Calcium iron aluminum oxide also contains a small amount of elements such as Si, P, Ti, Cr and S. In this specification, iron-based oxides also include compounds in which a part of the surface has been changed to hydroxides or the like by water vapor in the air, and calcium iron aluminum oxide includes water vapor in the air and carbon dioxide. And a compound in which a part of the surface has been changed to a hydroxide or a carbonate. In this specification, both iron-based oxides and calcium iron aluminum oxide have a part of the surface as a reactant with sulfur oxides (SOx) and nitrogen oxides (NOx) which are air pollutants. Includes those compounds that are altered.

Most of the iron-based oxides exist as wustite-based oxides (FeO), and also exist as hematite-based oxides (Fe ₂ O ₄ ) and magnetite-based oxides (Fe ₃ O ₄ ).

Among these, the wustite-based oxide and the hematite-based oxide are formed by crushing or pulverizing steelmaking slag because the magnetite-based oxide (Fe ₃ O ₄ ), which is a ferromagnetic substance, is dispersed therein. After that, it can be separated and recovered from the steelmaking slag by magnetic separation. In addition, the magnetite-based oxide alone or coexisting with another iron-based oxide can be separated and recovered from the steelmaking slag by magnetic separation.

  Since the calcium iron aluminum oxide is magnetized to become a magnetic material, it can be separated from the steelmaking slag by magnetic separation and recovered.

  Iron-based oxides and calcium iron aluminum oxide (hereinafter collectively referred to as “iron-based compounds”) have a small phosphorus content of 0.1% by mass or less. If separated and recovered from slag, it can be used as a raw material for blast furnace and sintering.

  In the future, due to changes in the social environment, the number of civil works to use steelmaking slag as roadbed material, civil engineering material, cement material, etc. will decrease, and the land where steelmaking slag can be landfilled will decrease. There is also a possibility. From this viewpoint, it is expected that the iron-based compound contained in the steelmaking slag is recovered to reduce the volume of the steelmaking slag to be reused or landfilled.

  Further, Mn, Mg, Ca and the like contained in the iron-based compound are useful elements in iron making, and can be used as materials for iron making. For example, Mn is an element that contributes to improving the strength and stabilizing the strength of a steel material, and Mg is an element that enhances the fluidity of slag in a blast furnace. Ca is a main constituent element of slag in blast furnaces and steelmaking, and is an important element for adjusting the basicity and viscosity of slag, but can also be used as a dephosphorizing agent for molten steel.

  Metallic iron is Fe entrained in the slag in the steelmaking process and minute Fe precipitated during solidification of the steelmaking slag. Large metallic irons are separated and collected by magnetic separation or other methods in a dry process of crushing or pulverizing steelmaking slag in the atmosphere.

  Slag particles obtained by crushing or pulverizing steelmaking slag are often suspended in a liquid such as water to be slurried, and then flowed over the drum surface for magnetic selection. In the atmosphere, when the particles are small, they are agglomerated, so that it becomes difficult to separate the iron compound from the others by magnetic separation. However, when the slurry is formed, the particles can be dispersed by the liquid without agglomeration, and can be separated by magnetic separation.

  Examples of the magnetic separation method include methods described in Patent Literature 1 and Patent Literature 2. In the case of industrial large-scale treatment such as magnetic separation for recovering the iron-based compound and metallic iron, a drum-type magnetic separation method using a rotary drum having a magnet fixed inside is often used. In the drum-type magnetic separation method, a magnet is fixed in a drum and an outer drum is rotated. The iron-based compound and metallic iron are captured on the surface of the rotary drum where a magnetic field is formed by the magnet, and move along the outer periphery of the rotary drum.

JP 2005-049214 JP 2009-189964 A

Masao Nakagawa, "Situation of Effective Utilization of Steel Slag", Textbook of the 205th and 206th Nishiyama Memorial Technical Lecture, Japan Iron and Steel Association, June 2011, p. 25-56 "Environmental Materials Iron and Steel Slag", Iron and Steel Slag Association, January 2014 Takayuki Futatsuka et al., "Effects of elution of components from steel slag into artificial seawater", Iron and Steel, Vol. 89, no. 4, January 2014, p. 382-387

  As described above, there are many advantages of recovering an iron-based compound from steelmaking slag. Therefore, there is always a demand to increase the recovery rate and recovery efficiency of iron atoms (Fe) by magnetic separation from steelmaking slag. In particular, from the viewpoint of using the recovered Fe as a raw material for a blast furnace or sintering, it is desirable that the Fe concentration in the recovered material is higher.

  In view of the above problems, the present invention provides a magnetic separation method for recovering an iron-based compound and metallic iron by magnetic separation from a slurry-like steelmaking slag, wherein a magnetic separation method for a steelmaking slag capable of increasing the Fe concentration in the recovered material, and An object of the present invention is to provide a magnetic separator for steelmaking slag that can be used in the method.

  In view of the above object, the present invention provides a rotary drum having a magnetic field formed on at least a part of a surface thereof, wherein a step of injecting a slurry containing crushed or pulverized particulate steelmaking slag onto the surface, Spraying a liquid on the surface of the rotary drum where the magnetic field is formed, and rotating and moving along the surface of the rotary drum, removing a liquid component and non-magnetic particles contained in the slurry. And a magnetic separation method for steelmaking slag.

  Further, the present invention provides a rotary drum having a magnetic field formed on at least a part of its surface, and a particulate steelmaking slag crushed or pulverized on the surface, which is arranged in this order in the rotation direction of the rotary drum. A nozzle for injecting a slurry containing the slurry, a slurry tank for bringing the slurry containing the steelmaking slag into contact with the rotary drum, and a liquid on a surface of the rotary drum on which the magnetic field is formed, thereby rotating the rotary drum. The present invention relates to a magnetic separation apparatus for steelmaking slag, comprising: a liquid spraying section that rotates and moves along the surface of a rotary drum and removes liquid components and non-magnetized matters contained in the slurry.

  According to the present invention, in a magnetic separation method for recovering an iron-based compound and metallic iron from a slurry-like steelmaking slag by magnetic separation, a magnetic separation method for a steelmaking slag capable of increasing the Fe concentration in the recovered material, and the method A usable magnetic separator for steelmaking slag is provided.

FIG. 1 is a flowchart of a magnetic separation method for steelmaking slag according to an exemplary embodiment of the present invention. It is a schematic cross section along the rotation direction of a rotary drum which shows a mode that a slurry is magnetically selected using a conventional magnetic separation device. FIG. 3A is a schematic cross-sectional view along a rotation direction of a rotary drum showing a configuration of a magnetic separation apparatus used for magnetically separating a slurry in an exemplary embodiment of the present invention. FIG. 3B is a schematic cross-sectional view along the direction of rotation of a rotary drum showing the configuration of another magnetic separation device used for magnetically separating a slurry in an exemplary embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a manner in which a slurry is magnetically separated in an exemplary embodiment of the present invention, along a rotation direction of a rotary drum. FIG. 5A is a schematic cross-sectional view along the rotation direction of the rotary drum showing the magnet arrangement inside the rotary drum in an exemplary embodiment of the present invention, and FIG. 5B shows the area shown in FIG. 5A. It is a schematic diagram which shows a mode when it sees from the surface of a magnet. FIG. 5C is a schematic cross-sectional view along the direction of rotation of the rotary drum showing another arrangement of magnets inside the rotary drum in an exemplary embodiment of the invention, and FIG. 5D is shown in FIG. 5C. FIG. 4 is a schematic diagram showing a state when a region viewed is viewed from the surface of a magnet. FIG. 6A is an exemplary embodiment of the present invention showing the direction of rotation of the rotary drum, with the contact surface of the drum and the spray water positioned so as to be above the south pole of the magnet inside the rotary drum. FIG. FIG. 6B is an exemplary embodiment of the present invention, showing the direction of rotation of the rotary drum, with the contact of the drum surface and the blast water positioned above the N pole of the magnet inside the rotary drum. FIG. FIG. 6C shows an exemplary embodiment of the present invention in which the contact between the drum surface and the spray water is located between the north and south poles of the magnet inside the rotary drum. It is a schematic cross section along the rotation direction of a type drum. FIG. 6D illustrates an exemplary embodiment of the present invention along the direction of rotation of the rotary drum, with the contact between the drum surface and the blast water off the magnet inside the rotary drum. It is a schematic cross section. FIG. 7A is a schematic diagram illustrating a method of spraying a liquid on the surface of a rotary drum in an exemplary embodiment of the invention. FIG. 7B is a schematic diagram illustrating another method of spraying liquid onto the surface of a rotating drum in an exemplary embodiment of the invention. FIG. 8A is a schematic cross-sectional view along the direction of rotation of the rotary drum, showing the direction of spraying liquid onto the surface of the rotary drum in an exemplary embodiment of the invention. FIG. 8B is a partial schematic cross-sectional view along the direction of rotation of the rotary drum, showing the angle at which gas is blown onto the surface of the rotary drum in an exemplary embodiment of the invention. FIG. 9A is a schematic cross-sectional view taken along a rotation direction of a rotary drum, showing a state in which a liquid and a gas are sprayed in this order to magnetically select a slurry in an exemplary embodiment of the present invention. FIG. 9B is a schematic cross-sectional view of the exemplary embodiment of the present invention, showing a manner in which a gas and a liquid are sprayed in this order to magnetically select a slurry, along the rotation direction of the rotary drum.

  Hereinafter, a magnetic separation method for a steelmaking slag according to an exemplary embodiment of the present invention will be described together with a magnetic separation apparatus used in the method.

  FIG. 1 is a flowchart illustrating a method for magnetically separating steelmaking slag according to the present embodiment.

(Step S110)
The size of the structure such as calcium silicate, free lime, and iron-based compounds contained in the steelmaking slag is about 1000 μm or less. Therefore, separation and recovery of components such as iron-based compounds from steelmaking slag are performed by crushing or pulverizing steelmaking slag.

  The type of steelmaking slag is not particularly limited as long as it is slag discharged in the steelmaking process. Examples of steelmaking slag include converter slag, pretreatment slag, secondary refining slag, and electric furnace slag.

  The steelmaking slag is crushed or pulverized after being discharged in the steelmaking process to form particulate slag particles. The maximum particle size of the slag particles is preferably equal to or less than the size of the structure of the iron-based compound, and more preferably 1000 μm or less. When the maximum particle size is 1000 μm or less, the iron-based compound can exist as a single particle, and thus the iron-based compound can be easily selectively separated by magnetic separation. From the same viewpoint, the maximum particle size of the slag particles is preferably 500 μm or less, more preferably 250 μm or less, and even more preferably 150 μm or less. The slag particles can be reduced to such an extent that the maximum particle size falls within the above range, for example, by further crushing the crushed slag particles with a crusher including a hammer mill, a roller mill, a ball mill and the like.

  The steelmaking slag is preferably subjected to a heat treatment before the magnetic separation. When the steelmaking slag is heat-treated, the magnetization of the iron-based compound increases, and a larger amount of the iron-based compound can be removed by magnetic separation. The heat treatment is preferably performed at a temperature of 300 ° C. or more and 1000 ° C. or less for 0.01 minute or more and 180 minutes or less.

  The steelmaking slag may be a filtration residual slag obtained by immersing the steelmaking slag in water, leaching free lime and calcium hydroxide, and leaching Ca of the surface layer of the Ca compound, and then filtering. . In addition, it may be a filtration residual slag obtained by contacting an aqueous solution containing carbon dioxide alone to elute Ca and then filtering. When the residual slag is used, since the slag particles having a small amount of Ca are used, it is possible to further increase the Fe concentration in the recovered material, and also to separate and recover the Ca from the slag particles not recovered by the magnetic separation. It will be easier.

(Step S120)
Since the slag particles having such a small particle size have low dispersibility in air and are likely to be aggregated by the magnetic field during magnetic separation, the slag particles containing a large amount of iron-based compounds and other compounds are more likely to be formed. It is difficult to separate from the slag particles. Therefore, the slag particles are often suspended in a liquid to be slurried and magnetically selected. When slag particles are suspended in a liquid, Ca is eluted from free lime and calcium silicate in the slag particles, and the slurry becomes alkaline. In an alkaline solution, since each slag particle is negatively charged, the dispersibility of the slag particle is increased, and the slag particle containing a large amount of iron-based compound and the slag particle containing a large amount of other compounds are separated and collected. Cheap. In addition, even if the above-mentioned slag after filtration is suspended in a liquid, the dispersibility of the slag particles is improved due to the elution of Ca remaining in the slag particles. Inexpensive water is often used as the liquid.

  From the viewpoint of improving both the fluidity of the slurry and the recovery efficiency of Fe, the ratio by mass between the steelmaking slag and water is (massmaking slag / water) = 1/300 or more and 1/2 or less in terms of mass ratio. Preferably, it is more preferably 1/200 or more and 1/5 or less, and further preferably 1/100 or more and 1/10 or less.

  The slurry containing such slag particles (hereinafter, also simply referred to as “slurry”) includes slag particles (hereinafter, also referred to as “highly magnetized particles”) containing a large amount of iron-based compounds and having high magnetization, free lime, and silica. Includes slag particles (hereinafter also referred to as “low-magnetization particles”), which contain a large amount of calcium acid and the like but have a small amount of iron-based compound and small magnetization (hereinafter, also referred to as “low-magnetization particles”), metallic iron, and liquid components.

(Step S130)
The slurry is sprayed on the surface of a rotary drum having a magnetic field formed on at least a portion of the surface. Thereby, the highly magnetized particles and the metallic iron come into contact with the surface of the rotary drum, are captured on the drum surface by the magnetic field, are moved in the rotation direction of the rotary drum, and are collected by the collection unit. On the other hand, the low-magnetization particles and the liquid component contained in the slurry are not captured by the surface of the rotary drum, and do not move in the rotation direction of the rotary drum, and are discharged from the discharge unit without being recovered by the recovery unit. It is preferable that the slurry is sprayed on a region of the surface of the rotary drum where a magnetic field is formed, but is sprayed on a region where a magnetic field is not formed, and the slurry is rotated along the surface of the rotary drum. The movement may be moved to a region where a magnetic field is formed.

  When the slurry is sprayed toward the surface of the rotary drum, the slag particles in the slurry travel straight toward the drum by inertia. As a result, even if the average distance between the drum and the tank (hereinafter, referred to as the slurry flow path) is increased, the effective adhesion area does not decrease, and the slag recovery rate does not decrease, so that the width of the slurry flow path can be increased. . As a result, the amount of slurry that can be flowed per unit time increases, and more efficient magnetic separation can be performed as compared with the related art.

  At this time, the low-magnetization particles and a part of the liquid component may move to the collection section along the surface of the rotary drum, and may be collected together with the high-magnetization particles. In order to increase the Fe concentration contained in the recovered material separated and recovered by the magnetic separation, the amount of the high-magnetic particles and the metallic iron separated and recovered is increased, while the low-magnetic particles and the liquid component recovered above are recovered. It is desirable to sort the high-magnetization particles and the low-magnetization particles so as to reduce the amount of the particles.

(Step S140)
Therefore, in the present embodiment, the liquid is sprayed on the surface of the rotary drum contacted with the slurry to separate the liquid component and the low Fe concentration slag moving along the surface of the rotary drum from the highly magnetized particles and the metallic iron. And, the steelmaking slag is sorted according to the level of magnetization.

  Next, the manner in which the slurry is magnetically selected using the conventional magnetic separation apparatus 100 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view along the rotation direction X of the rotary drum of the conventional magnetic separation apparatus 100.

  The slurry is supplied from the slurry supply unit 110 to the slurry tank 120, and contacts the surface of the rotary drum 130 in the slurry tank 120. At this time, the highly magnetized particles 180 contained in the slurry are captured on the surface of the rotary drum 130 by the magnetic field formed by the magnet 140 and moved in the rotation direction of the rotary drum 130, and thereafter, the highly magnetized particles and the drum It adheres to the drum surface due to the adhesive force due to the wettability of water existing between the surfaces, and moves to the collection unit 160 along the surface of the rotary drum. The high-magnetization particles include metallic iron.

  At this time, a part of the liquid component 190 contained in the slurry is discharged from the slurry discharge part 150, but another part moves along the surface of the rotary drum 130 together with the high-magnetization particles 180 and moves to the collection part. Collected at 160.

  It is considered that this is because the liquid component 190 contains Ca eluted from the slag particles and has high wettability to the surface of the rotary drum 130 and the highly magnetized particles 180. That is, since the liquid component 190 has a high wettability to the surface of the rotary drum 130, it is difficult for the liquid component 190 to separate from the surface of the rotary drum 130 and moves along the outer periphery of the rotary drum 130, and a part of the liquid component 190 is collected by the collection unit. It is believed to reach 160. In addition, since the liquid component 190 also has high wettability to the highly magnetized particles 180, the liquid component 190 moves along the outer periphery of the rotary drum 130 accompanying the high magnetized particles 180 captured on the surface of the rotary drum 130, It is considered that a part thereof reaches the collection unit 160.

  When the liquid component 190 reaches the collection unit 160 in this manner, in addition to the high-magnetization particles 180 containing a large amount of Fe, the low-magnetization particles suspended in the liquid component 190 are also collected by the collection unit 160. Is difficult to increase to a desired level. Further, the amount of the liquid component 190 moving along the surface of the rotary drum 130 per unit area increases substantially in proportion to the half power of the peripheral speed of the rotary drum 130. However, the amount of highly magnetized particles per unit area captured on the surface of the rotary drum is constant independently of the peripheral speed of the rotary drum. Therefore, it is considered that as the peripheral speed of the rotary drum 130 increases, the accompanying amount of the liquid component 190 increases, and the Fe concentration in the recovered material decreases. The reason why the amount of captured high-magnetization particles does not depend on the peripheral speed of the rotary drum is considered to be that the amount of captured high-magnetization particles mainly depends on the magnetic flux density on the surface of the rotary drum. That is, when a certain amount or more of the highly magnetized particles adhere to the drum surface, the magnetic flux density on the surface decreases due to the magnetic shielding effect, and it becomes impossible to capture any more highly magnetized particles. Therefore, even if the peripheral speed is changed, the amount of captured high magnetization particles does not change much.

  Next, the reason why the use of the magnetic separation method for steelmaking slag and the magnetic separation apparatus for steelmaking slag of the present invention increases the Fe concentration in the recovered material will be described below.

  FIGS. 3A and 3B are schematic cross-sectional views along the rotation direction X of the rotary drum, showing the configuration of the magnetic separation device 200 used for magnetically separating the slurry in the present embodiment.

  The magnetic separation device 200 includes a rotary drum 230 in which a magnet 240 is fixed and disposed, and a rotary drum 230 arranged in this order along the outer circumference of the rotary drum 230 in the rotation direction of the rotary drum 230 (the arrow X direction in the drawing). A slurry supply unit 210, a slurry tank 220, a slurry discharge unit 250, and a recovery unit 260.

  As shown in FIGS. 3A and 3B, the magnetic separation device 200 causes the slurry supply unit 210 to eject slurry. When the slurry is ejected, the direction of the slurry flow changes in the circumferential direction of the drum. At this time, the slag particles in the slurry advance straight toward the drum due to inertial force. This allows more slag particles to reach the drum surface where the magnetic field is formed. In addition, since the slag particles travel straight toward the drum, the slag particles reach the drum surface where the magnetic field is formed even when the slurry flow path is enlarged. The ejection speed (flow rate) of the slurry is preferably from 10 m / min to 5,000 m / min, and more preferably from 100 m / min to 3,000 m / min. The slurry flow path is preferably 1 mm or more and 100 mm or less, more preferably 2 mm or more and 50 mm or less.

  Further, the magnetic separation device 200 has a liquid spraying unit 270 disposed between the slurry discharge unit 250 and the recovery unit 260, and sprays the liquid from the liquid spraying unit 270 to the surface of the rotary drum 230. FIG. 4 is a schematic cross-sectional view showing the manner in which the slurry is magnetically separated using the magnetic separation device 200, along the rotation direction of the rotary drum. In the magnetic separation method of the present embodiment, as shown in FIG. 4, the liquid component 290 and the non-magnetic material not captured on the surface of the rotary drum 230 are discharged from the surface of the rotary drum 230 by spraying the liquid from the liquid spraying unit 270. At the same time as removing, the magnetic substance magnetically attached to the drum is washed away. Among the washed magnetic substances, the highly magnetized particles re-magnetize at the portion where the flow velocity of the liquid is low. As a result, the highly magnetized particles 280 are more accurately selected and separated and recovered from the liquid component 290 and the low magnetized particles suspended in the liquid component 290. Therefore, the magnetic separation method of the present embodiment using the magnetic separation device 200 can further increase the Fe concentration in the recovered material.

  The slurry supply unit 210 is an injection device for supplying slurry to the slurry tank 220.

  The slurry tank 220 holds the supplied slurry, contacts the held slurry with the surface of the rotary drum 230, and causes the magnetic particles formed by the magnet 240 to move the highly magnetized particles in the slurry onto the surface of the rotary drum 230. This is a tank for catching. The slurry tank 220 may be a flow path for flowing the slurry supplied from the slurry supply unit 210 to the slurry discharge unit 250 as shown in FIG. 3A, or a storage tank for temporarily storing the supplied slurry. There may be. Unwanted low-magnetization particles near the surface in the particles trapped on the drum are removed by the fluid drag of the slurry flowing through the slurry tank.

  The flow rate of the slurry in the slurry tank when the slurry is flowing may be the same as the peripheral speed of the rotary drum, may be higher than the peripheral speed of the rotary drum, or may be lower than the peripheral speed of the rotary drum. From the viewpoint of further improving the efficiency of removing low-magnetization particles, the difference between the flow rate of the slurry and the peripheral speed of the rotating drum is preferably 5 m / min or less.

  It is preferable that a predetermined amount of slurry is stored in the slurry tank 220 during the magnetic separation. Thereby, the contact area between the rotary drum 230 and the slurry can be increased, and the slag collection efficiency can be increased. At this time, the storage amount of the slurry is preferably as large as possible, and is preferably 30% or more, more preferably 50% or more, and more preferably 70% or more with respect to the maximum storage amount of the slurry in the slurry tank 220. More preferably, it is particularly preferably 90% or more.

  The rotary drum 230 is a rotary hollow drum whose surface is configured to be rotatable. The rotary drum 230 has a magnet 240 fixedly disposed therein so as not to rotate.

  The surface of the rotary drum 230 may be formed from a non-magnetic material, for example, an austenitic phase-stabilized austenitic stainless steel, titanium, plastic, ceramic or the like.

  From the viewpoint of moving the highly magnetized particles trapped on the surface to the collection unit 260, the peripheral speed of the rotary drum 230 during the magnetic separation is preferably 0.1 m / min or more and 1000 m / min or less, and 1 m / min. It is more preferably at least 500 m / min and more preferably at least 5 m / min and at most 300 m / min.

  The magnet 240 is fixedly arranged along the inner periphery of the rotary drum 230 at a position at least partially overlapping the area where the slurry tank 220 is arranged. The magnet 240 forms a magnetic field on the surface of the rotary drum 230 and captures highly magnetized particles contained in the slurry on the surface of the rotary drum 230. The magnet 240 is fixedly disposed. When the surface of the rotary drum 230 rotates, the magnet 240 does not follow the rotation of the surface, and the magnet 240 is fixedly disposed inside the surface of the rotary drum 230. A magnetic field is formed in the region.

  The magnet 240 may be a permanent magnet or an electromagnet. From the viewpoint of reducing costs and controlling the magnetic field distribution easily, a permanent magnet is preferable.

  Although there is a difference in magnetization between the high-magnetization particles and the low-magnetization particles, both are magnetized, and thus cannot be sorted out by simply applying a magnetic force as in normal magnetic separation. The magnet 240 is preferably a magnet that sets the maximum value of the magnetic flux density in the vertical direction on the surface of the rotary drum 230 to 50 G or more, from the viewpoint of more easily capturing the high magnetization particles on the surface of the rotary drum 230, It is more preferable that the magnet be 100 G or more. In addition, the magnet 240 has a maximum value of the magnetic flux density in the vertical direction on the surface of the rotary drum 230 of 4000 G or less from the viewpoint of making it difficult to capture the low-magnetization particles and suppressing a decrease in the Fe concentration in the collected material. It is preferably a magnet, and more preferably a magnet of 1500 G or less.

  It is preferable that a plurality of magnets are arranged along the inner circumference of the rotary drum 230.

  At this time, the plurality of magnets are preferably arranged such that the maximum value of the absolute value of the magnetic flux density in the region to which the liquid is sprayed is larger than in other regions. The region to which the gas is blown means a region on the surface of the rotary drum 230 that is located on an extension of the center of the flow of the liquid.

  At this time, the plurality of magnets are arranged such that magnetic fields in different directions along the rotation direction of the rotary drum 230 are alternately formed on the surface of the rotary drum 230 as shown in FIGS. 5A and 5B. Preferably, they are arranged. 5A is a schematic cross-sectional view showing a partial area of the magnet 240 along the rotation direction of the rotary drum, and FIG. 5B is a view of the area shown in FIG. It is a schematic diagram which shows a situation. Specifically, the plurality of magnets include a magnet 240a arranged with the north pole facing the surface of the rotary drum 230 and a magnet 240b arranged with the south pole facing the surface of the rotary drum 230. It is preferred to include. It is preferable that the magnet 240a arranged with the north pole facing and the magnet 240b arranged with the south pole facing are alternately arranged in the rotation direction of the rotary drum 230. With such an arrangement, the plurality of magnets rotate the high-magnetization particles captured on the surface of the rotary drum 230 during movement due to a change in the direction of the magnetic field, and slip into the vicinity of the high-magnetization particles. The low-magnetization particles are desorbed, and the Fe concentration in the recovered material can be further increased. More specifically, particles dropped by the sprayed liquid pass through a portion having a low magnetic flux density and are re-entrapped in a plurality of portions having a high magnetic flux density below. During this time, unnecessary low magnetization particles are removed. Since the drum rotates, such an action occurs continuously, the ratio of the high-magnetization particles increases, and the Fe concentration of the recovered material increases. As shown in FIGS. 5C and 5D, the plurality of magnets are arranged on the surface of the rotary drum 230 such that magnetic fields in different directions are formed alternately along a direction orthogonal to the rotation direction of the rotary drum 230. The effect is greater when the plurality of magnets are arranged as shown in FIGS. 5A and 5B than when.

  Further, at this time, from the viewpoint of suppressing the desorption of the high-magnetization particles due to the liquid to be sprayed, the plurality of magnets, on the surface of the rotary drum 230, reduce the region where the absolute value of the magnetic flux density in the vertical direction is low. It is preferable that they are arranged as follows. Specifically, the plurality of magnets are arranged on the surface of the rotary drum 230 at intervals between regions where the absolute value of the magnetic flux density in the vertical direction is 50% or more of the maximum value on the surface (hereinafter simply referred to as “ (Also referred to as “50% magnetic flux interval”) is preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 30 mm or less. . With such an arrangement, even if the high-magnetization particles trapped in one region are moved by spraying the liquid or the like, the high-magnetization particles are likely to be trapped in another region, and the high-magnetization particles are removed. Separation is suppressed.

  The slurry discharge unit 250 is a flow path for discharging the low-magnetization particles and the liquid component not captured on the surface of the rotary drum 230 by the magnetic field to the outside of the magnetic separation device 200. The slurry discharge unit 250 may be disposed at the end of the slurry tank 220 as shown in FIG. 3A, or may be disposed in the middle of the slurry tank 220 as shown in FIG. May be. In order to increase the contact area between the steelmaking slag and the rotary drum, it is preferable that the lower surface of the rotary drum is immersed in the slurry in the slurry tank.

  The collection unit 260 collects the high magnetization particles 280 captured on the surface of the rotary drum 230 and moved along the outer circumference of the rotary drum 230.

  The liquid spraying section 270 has a nozzle 275 for ejecting the liquid, and sprays the liquid ejected from the nozzle 275 to the surface of the rotary drum 230. As a result, as shown in FIG. 4, the high magnetization particles 280 are separated from the liquid component 290 and the low magnetization particles, and the liquid component 290 and the low magnetization particles suspended in the liquid component 290 are removed and the slurry discharge unit 250 is removed. Is discharged from

  The liquid spraying unit 270 is located at an intermediate position between the slurry tank 220 and the collecting unit 260 along the rotation direction X, that is, between the slurry tank 220 and the collecting unit 260, at a position where the liquid is sprayed on the surface of the rotary drum 230. It should just be arranged in.

  Since slag particles contain Mn, Mg, and the like in addition to Fe, even high-magnetization particles have smaller magnetization than metal iron or the like, and are easily detached from the surface of the rotary drum 230. Therefore, from the viewpoint of suppressing detachment of the high-magnetization particles from the surface of the rotary drum 230 due to the spraying of the liquid, the liquid spraying unit 270 includes the surface of the rotary drum 230 as shown in FIGS. 6A, 6B, and 6C. As shown in (2), a magnet 240 is arranged inside, and is arranged at a position where the liquid is sprayed onto a region where at least one magnetic field is formed by the magnet 240. From the above viewpoint, the liquid spraying unit 270 sets the liquid flux in a region where the absolute value of the magnetic flux density in the vertical direction is 50% or more with respect to the maximum value of the absolute value of the magnetic flux density in the vertical direction on the surface of the rotary drum 230. Is preferably arranged at the position where the air is blown. In addition, disposing the liquid spraying unit 270 at a position shown in FIG. 6D where the liquid is sprayed to a region outside the region where the magnetic field is formed by the magnet 240 can eliminate the removal of highly magnetized particles from the surface of the rotary drum 230. It is not preferred because it promotes separation.

  In the case where almost all of the liquid component is removed from the surface of the rotary drum 230 due to gravity or the like during the movement along the surface of the rotary drum 230, the liquid spraying unit 270 may be used as the liquid component. Is preferably arranged at a position where the liquid is sprayed onto a region existing on the surface of the rotary drum 230. By spraying the liquid on such a region, the removal efficiency of the low-magnetization particles is further increased. When a gas is blown against the liquid component in such a region, the removal efficiency of the low-magnetization particles increases due to the fluid drag.

  In addition, when the liquid is sprayed, the magnetic substance once drops off due to the water flow at the position where the liquid is sprayed. Among the magnetically-deposited materials, the high-magnetization particles re-magnetize at a place where the flow is weak, but the low-magnetization particles flow away without being collected. By this action, the ratio of the high-magnetization particles in the collected material that reaches the collecting unit 260 and is collected increases, and the Fe concentration of the collected material increases. In order to increase the particle recovery rate, it is preferable that the shape of the liquid spray nozzle 275 and the liquid spray method be discontinuous spray in the width direction of the drum surface, such as a shower method shown in FIG. 7A. . By performing the spraying discontinuously, the locations where the flow is weak are increased, and the highly magnetized particles are concentrated in the locations where the flow is weak, thereby increasing the particle recovery rate. In the shower system, the shape of the liquid spray nozzle 275 and the flow of the liquid on the drum surface are more intense than in the system in which the liquid is sprayed continuously in the width direction of the drum surface such as the spray system shown in FIG. 7B. It is preferable because weak portions easily occur and re-magnetization of the high-magnetization particles also easily occurs. As a result, the particle recovery rate can be increased.

  Further, as shown in FIG. 8A, the liquid spraying unit 270 is illustrated as a direction (d1 to d3 in FIG. 8A) inclined with respect to a tangent (dashed line L in the figure) of the rotary drum 230 at the position where the liquid is sprayed. ) Is preferably disposed at a position where the above-mentioned gas is blown (illustrated as liquid spraying parts 270a, 270b and 270c in FIG. 8A). In addition, in this specification, the tangent of the rotary drum 230 at the position where the gas is blown means the tangent of the rotary drum 230 at the position where the gas is blown in a cross-sectional view along the rotation direction of the rotary drum. .

  As shown in FIG. 8B, the inclination angle θ is an angle (θ1 or θ2 in FIG. 8B) measured so that the angle of the rotary drum 230 with respect to the tangent L is 90 ° or less. When the angle θ is provided, the high-magnetization particles are pressed against the surface of the rotary drum 230 by the blown gas, so that the high-magnetization particles are desorbed by spraying the liquid, and particularly, the intermediate between the regions where the direction of the magnetic field is reversed. Thus, the detachment of the highly magnetized particles in a region where the magnetic flux density is partially weakened can be further suppressed. At this time, the low-magnetization component that is not captured on the surface of the rotary drum 230 is separated from the surface of the rotary drum 230 together with the liquid component due to the fluid drag or the like.

  Note that the liquid spraying unit 270 may be arranged at a position where the liquid is sprayed from the collection unit 260 side to the tangent to the rotary drum 230 (the liquid spraying unit 270a in FIG. 8A), and the tangent to the rotary drum 230. May be arranged at a position where the gas is blown vertically to the liquid (the liquid spraying unit 270b in FIG. 8A), or may be arranged at a position where the liquid is sprayed from the slurry tank 220 side (the liquid spraying unit in FIG. 8A). 270c).

  When spraying the liquid from the collection unit 260 side with respect to the tangent to the rotary drum 230 or the direction perpendicular to the tangent to the rotary drum 230 (d1 and d2 in FIGS. 8A and 8B), the angle θ1 is provided and When sprayed, desorption of the high-magnetization particles due to the liquid flow and reduction of the Fe recovery efficiency due to the desorbed high-magnetization particles being mixed into the liquid component and being separated together with the liquid component are less likely to occur, and slurry Of the surroundings due to the scattering of the liquid component contained in the water.

  When the liquid is sprayed from the slurry tank 220 side with respect to the tangent to the rotary drum 230 or from the direction perpendicular to the tangent to the rotary drum 230 (d2 and d3 in FIG. 8A), the angle θ2 is provided and the liquid is sprayed. Is sprayed, the amount of gas in the rotation direction of the rotary drum 230 is not increased more than necessary, so that the high magnetic particles are desorbed due to the liquid flow, and the liquid component and the low magnetic particles are sprayed to the recovery unit 260 side. The Fe concentration in the recovered material due to the movement and recovery is reduced, and the contamination of the surroundings due to scattering of the liquid component contained in the slurry is less likely to occur.

  From the above viewpoint, each of the angles θ1 and θ2 is preferably 40 ° or more and 90 ° or less with respect to a tangent, more preferably 55 ° or more and 90 ° or less, and 70 ° or more and 90 ° or less. It is more preferred that there be.

  In addition, from the viewpoint of promoting the separation of the highly magnetized particles and the liquid component by spraying the liquid and suppressing the desorption of the highly magnetized particles, the liquid spraying unit 270 has a flow velocity of 0.4 m / s or more and 4 m / s. The following gas is preferably blown, and more preferably 0.7 m / s or more and 3.5 m / s or less.

  Further, from the viewpoint of promoting the separation of the highly magnetized particles and the liquid component by spraying the liquid and suppressing the desorption of the highly magnetized particles, the liquid spraying unit 270 has a spray amount of 0.5 l / s · m or more. It is preferable to blow the gas having a flow rate of 0.5 l / s · m or less, and it is more preferable to blow the gas having a rate of 1.0 l / s · m or more and 5.0 l / s · m or less.

  The flow rate and the amount of the liquid are the flow rate and the amount when the liquid is sprayed on the surface of the rotary drum, and when the distance between the nozzle that blows the liquid and the surface on which the liquid is sprayed is sufficiently short (for example, 10 mm). In the following, the flow rate of the gas at the nozzle outlet and the amount of the liquid ejected from the nozzle outlet can be roughly regarded as the flow rate and the amount of the liquid sprayed on the surface of the rotary drum.

  The liquid to be sprayed is not particularly limited, and water, gasoline, and organic solvents such as acetone and ethanol can be used. Among these gases, water is preferable from the viewpoint of lowering the cost of magnetic separation. Further, calcium carbonate generated by the reaction between Ca eluted in the slurry and carbon dioxide contained in the gas acts as a binder to aggregate the low-magnetic particles with the high-magnetic particles, and the aggregated low-magnetic particles are collected. From the viewpoint of suppressing a decrease in the Fe concentration in the recovered material, the liquid preferably has a carbon dioxide concentration of less than 5% by volume. From the viewpoint of suppressing the reaction of the slurry with nitrogen oxides and sulfur oxides, the liquid preferably has a concentration of nitrogen oxides and sulfur oxides of less than 0.1% by volume.

  9A and 9B, the gas may be blown from the gas blowing unit 300 to further increase the concentration of the collected material, as shown in FIGS. 9A and 9B. As shown in FIG. 9A, spraying a liquid after spraying a liquid to wash out low-magnetization particles makes it possible to blow off a liquid that is slightly mixed with low-concentration particles attached to high-magnetization particles. , Since the Fe concentration is further improved. Blowing the gas after spraying the liquid, as shown in FIG. 9B, compared with the case where the spraying of the liquid is performed after the spraying of the gas, the low-concentration particles attached to the high-magnetization particles are somewhat less. This is preferable because the mixed liquid is easily blown off and the Fe concentration is easily improved.

  In addition, from the viewpoint of promoting the separation of the liquid component from the highly magnetized particles by spraying the gas and suppressing the desorption of the highly magnetized particles, the gas blowing unit 300 has a flow velocity of 10 m / s or more and 330 m / s or less. It is preferable to blow a certain gas, and it is more preferable to blow the gas at a speed of 20 m / s to 90 m / s.

  In addition, from the viewpoint of promoting the separation of the liquid component from the highly magnetized particles by spraying the gas and suppressing the desorption of the highly magnetized particles, the gas blowing unit 300 has a spray amount of 5 l / s · m or more and 165 l / s. M is preferably blown, and more preferably 10 l / s · m or more and 45 l / s · m or less.

  The flow velocity and the flow rate of the gas are the flow velocity and the flow rate when the gas is blown onto the surface of the rotary drum, and when the distance between the nozzle that blows out the gas and the surface to which the gas is blown is sufficiently close (for example, 10 mm). In the following, the flow rate of the gas at the nozzle outlet and the amount of the gas emitted from the nozzle outlet can be roughly regarded as the flow rate and the amount of the gas blown to the surface of the rotary drum.

  The gas to be blown is not particularly limited, and air (atmosphere), nitrogen, oxygen, hydrogen, water vapor, chlorofluorocarbon gas and the like can be used. Of these gases, air (atmosphere) is preferable from the viewpoint of lowering the cost of magnetic separation. Further, calcium carbonate generated by the reaction between Ca eluted in the slurry and carbon dioxide contained in the gas acts as a binder to aggregate the low-magnetic particles with the high-magnetic particles, and the aggregated low-magnetic particles are collected. From the viewpoint of suppressing a decrease in the Fe concentration in the recovered material, the gas preferably has a carbon dioxide concentration of less than 5% by volume. Further, from the viewpoint of suppressing the reaction between the slurry and nitrogen oxides and sulfur oxides, the concentration of the nitrogen oxides and sulfur oxides in the gas is preferably less than 0.1% by volume.

  Even when the surface of the rotary drum is coated with a resin such as a water-repellent urethane resin or a fluororesin, liquid components and non-magnetically attached substances that move along the outer circumference of the rotary drum accompanying the highly magnetized particles are removed. Therefore, the Fe concentration in the recovered material cannot be increased as in the present embodiment. Further, when spherical water droplets are formed on the surface of the rotary drum coated with the water-repellent resin, and the high-magnetization particles are taken into the water droplets, the high-magnetization particles are removed together with the water droplets. May decrease. The decrease in the Fe recovery efficiency is particularly likely to occur when the magnetic force on the surface of the rotary drum is weak (low magnetic flux density).

  In addition, even if a liquid is pressed against the surface of the rotary drum to squeeze out liquid components and non-magnetic particles, the liquid component and the low-magnetization particles to be removed are moved between the surface of the rotary drum and the surface of the roll. Since it passes through, the Fe concentration in the recovered material cannot be increased as in the present embodiment. In particular, since the surface after the high-magnetization particles have been magnetized usually has irregularities, it is difficult to efficiently remove the liquid component and the low-magnetization particles in the concave portions. Furthermore, in order to maintain the removal efficiency of the liquid component and the low-magnetization particles, maintenance for removing the slag particles adhered to the roll surface is required, and the operation efficiency of the magnetic separation is reduced.

  The solid or slurry-like steelmaking slag from which the iron-based compound and metallic iron have been removed by magnetic separation may be subjected to the above-described magnetic separation again in order to more sufficiently recover the iron-based oxide and metallic iron.

  The slurry-like steelmaking slag after the magnetic separation can be used as a cement material, a roadbed material, a civil engineering material, a fertilizer, and the like after recovering Ca and P by a known method as necessary.

  In addition, the recovered material collected by the magnetic separation contains a large amount of a compound containing Fe such as an iron-based compound and metallic iron, and can be reused as a raw material for a blast furnace or sintering.

  Hereinafter, the present invention will be described more specifically with reference to examples. It should be noted that these examples do not limit the scope of the present invention to the specific methods described below.

  A steelmaking slag having the components shown in Table 1 (the numerical values in Table 1 are mass%) was prepared. The types and amounts of the components contained in the steelmaking slag were measured by a chemical analysis method.

  The steelmaking slag was pulverized after heating in a 750 ° C. atmosphere for 60 minutes to increase the magnetization. The pulverization was performed to 200 μm or less by a dry ball mill, and then to 50 μm or less by a wet ball mill.

  The magnetic separation device having the configuration shown in FIG. 4 was used. A neodymium-based permanent magnet was arranged in the drum so that the N and S magnetic poles changed along the rotation direction X of the drum. The magnet was disposed at a position inside the drum corresponding to the portion from the slurry supply port to the liquid (gas) spraying portion. The center of the flow of the water to be blown and the center of the airflow were made to be directly above the position where the magnetic flux density in the vertical direction by the magnet arranged inside the area to be blown was maximum.

[Experiment 1]
The relationship between the slurry charging method, the peripheral speed of the drum and the flow rate of the sprayed water, the slurry flow path, the Fe concentration of the magnetically separated product, and the slag recovery weight per minute was investigated. The experimental conditions including those conditions were as shown in Table 2. The slurry flow path was a distance between the container and the drum, and the slurry flow rate was a calculated value when the slurry was flowed through the slurry flow path.

  After the supply of the slurry to the magnetic separation apparatus, the weight of the recovered material, the types and amounts of components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. In addition, as an index of the recovery efficiency, the slag recovery weight per minute was calculated from the weight of the recovered material and the time required from the start to the end of slurry supply (magnetic separation time).

  Table 3 shows the relationship between the peripheral speed of the drum, the flow rate of the sprayed water, the width of the slurry flow path, the Fe concentration of the magnetically separated product, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  When water was sprayed on the rotary drum, the Fe concentration in the recovered material was higher than when water was not sprayed (Test 6). This is because the liquid component and low-magnetization particles that adhere to the drum and rotate and move are removed, and the amounts of the liquid component and low-magnetization particles collected together with the high-magnetization particles are reduced.

  On the other hand, when water was sprayed on the rotary drum, the Fe concentration stably increased to 33% or more even when the peripheral speed of the drum was increased.

  When the slurry was sprayed from the side of the container, the slag recovery weight when the slurry flow path was expanded to increase the slag recovery weight per minute was higher than when the slurry was charged along the container (Test 5). . This is because the method of injecting slurry from the container side (FIG. 4) is different from the method of injecting slurry from the container side, in that the slurry flows toward the vicinity of the drum and the amount of particles passing near the drum having a high magnetic flux density is reduced. It is because it increased.

[Experiment 2]
The relationship between the amount of slurry in the slurry tank, the Fe concentration of the magnetically collected product, and the slag recovery weight per minute was investigated. The experimental conditions were changed as shown in Table 4 and the amount of slurry stored in the tank during the experiment was changed by operating the discharge valve.

  After continuously supplying the slurry to the magnetic separation device for a predetermined time, the weight of the recovered material, the type and the amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 5 shows the relationship between the amount of slurry stored in the slurry tank, the Fe concentration of the magnetically separated product, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  The lower the opening of the discharge valve, the higher the slag collection weight per minute. This is because, as the opening of the discharge valve decreases and the amount of slurry in the slurry tank increases, the contact area between the rotary drum and the slurry increases.

[Experiment 3]
The relationship between the arrangement method of the magnets, the Fe concentration of the magnetically collected material, and the slag recovery weight per minute was investigated. The experimental conditions were changed as shown in Table 6.

  After continuously supplying the slurry to the magnetic separation device for a predetermined time, the weight of the recovered material, the type and the amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 7 shows the relationship between the arrangement method of the magnets, the Fe concentration of the magnetically separated product, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  When the magnetic field was formed alternately in the circumferential direction of the rotary drum, the slag recovery weight per minute was higher. This is because the high-magnetization particles captured on the surface of the rotary drum are rotated during movement by a change in the direction of the magnetic field, and the low-magnetization particles that have entered near the high-magnetization particles are desorbed.

[Experiment 4]
The interval between the magnets is set so that the absolute value of the magnetic flux density in the vertical direction between the magnets on the drum surface is always 50% or more of the maximum value of the absolute value of the magnetic flux density in the vertical direction formed by each magnet. The change in the Fe concentration of the magnetically separated product and the slag recovery weight per minute was investigated. The experimental conditions were changed as shown in Table 8. The magnetic flux density was measured by applying a magnetometer to the drum surface.

  After continuously supplying the slurry to the magnetic separation device for a predetermined time, the weight of the recovered material, the type and the amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 9 shows the relationship between the magnet spacing, the Fe concentration of the magnetically separated product, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  When the distance between the magnets at which the magnitude of the magnetic flux density in the vertical direction became 50% or more was 50 mm or less, the movement of the magnetically attached material due to spraying of water did not occur.

[Experiment 5]
The relationship between the magnetic field at the place where water spraying was performed, the Fe concentration of the magnetically collected material, and the slag recovery weight per minute was investigated. The experimental conditions were changed as shown in Table 10.

  After continuously supplying the slurry to the magnetic separation device for a predetermined time, the weight of the recovered material, the type and the amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 11 shows the relationship between the magnetic field at the place where water spraying is performed, the Fe concentration of the magnetically collected material, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  When there was no magnetic field in the area where water was sprayed, the magnetized material could not be recovered because it was washed away. On the other hand, when water was sprayed on a portion where a magnetic field was present, a recovered material having a high Fe concentration was stably obtained.

[Experiment 6]
The relationship between the nozzle shape, the Fe concentration of the magnetically collected product, and the slag collection weight per minute was investigated. The experimental conditions were changed as shown in Table 12.

  After continuously supplying the slurry to the magnetic separation device for a predetermined time, the weight of the recovered material, the type and the amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 13 shows the relationship between the nozzle shape, the Fe concentration of the magnetically collected product, and the slag collection weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  Regardless of the shower shape or the spray shape of the nozzle, it was confirmed that the magnetically attached material fell off from the portion sprayed with water. When the nozzle shape was a shower, it was confirmed that the dropped magnetic substance moved to a location not exposed to water and was re-magnetized.

[Experiment 7]
The relationship between the angle at which water was sprayed, the Fe concentration of the magnetically collected material, and the slag recovery weight per minute was investigated. The experimental conditions were changed as shown in Table 14.

  After continuously supplying the slurry to the magnetic separation apparatus for a predetermined time, the weight of the recovered material, the type and amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 15 shows the relationship between the magnetic field at the place where the water spraying is performed, the Fe concentration of the magnetically collected product, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  In Table 15, when the water spray angle is a positive value, it is determined that water is sprayed from the collecting section 260 side of the rotary drum at an angle described with respect to the tangent of the rotary drum. When the angle is a negative value, it indicates that water is sprayed from the slurry tank 220 side of the rotary drum at an angle described with respect to a tangent to the rotary drum.

  In particular, when water is sprayed on the rotary drum at an angle of about 90 °, the impact of the spray is transmitted to the drum without waste, thereby efficiently removing low-grade magnetic particles and the contact time between the magnetic particles and water. And the number of high-grade magnetic deposits falling off was reduced.

[Experiment 8]
The changes in the Fe concentration of the magnetically collected material and the slag recovery weight per minute when water and air were sprayed were investigated. The experimental conditions were changed as shown in Table 16.

  After continuously supplying the slurry to the magnetic separation device for a predetermined time, the weight of the recovered material, the type and the amount of the components contained in the recovered material were measured by a chemical analysis method, and the amount of Fe in the recovered material was measured. Was measured. In addition, the slag recovery weight per minute was calculated from the weight of the recovered material and the magnetic separation time.

  Table 17 shows the relationship between the magnetic field under the conditions of water spraying and air spraying, the Fe concentration of the magnetically collected product, and the slag recovery weight per minute. Those having an Fe concentration of 33% or more were regarded as acceptable levels.

  When water was sprayed on the rotary drum, the Fe concentration in the recovered material was higher than when only air was sprayed. When air was sprayed after water was sprayed, the Fe concentration in the recovered material became higher than when only water was sprayed. In particular, when air was sprayed after water was sprayed, the slag recovery weight per minute was higher than when air was sprayed and then water.

  INDUSTRIAL APPLICABILITY The present invention can recover a higher concentration of Fe from steelmaking slag by magnetic separation, and thus is useful as a method for recovering Fe resources in ironmaking.

100, 200 Magnetic separation device 110, 210 Slurry supply unit 120, 220 Slurry tank 130, 230 Rotary drum 140, 240 Magnet 150, 250 Slurry discharge unit 160, 260 Recovery unit 180, 280 High magnetization particles 190, 290 Liquid component 240a Rotation Magnet 240b arranged with N pole facing the surface of the rotary drum 240 Magnet placed with S pole facing the surface of the rotary drum 255 Discharge valve 270, 270a, 270b, 270c Liquid spray unit 275 Liquid spray nozzle 300 Gas Spraying part

Claims (8)

Injecting a slurry containing crushed or pulverized particulate steelmaking slag to the surface of a rotary drum having a magnetic field formed on at least a portion of the surface,
A liquid is sprayed onto a region of the surface of the rotary drum where the magnetic field is formed to remove a liquid component and non-magnetically attached matter contained in the slurry, which rotate and move along the surface of the rotary drum. Process and
A magnetic separation method for steelmaking slag, including: The rotary drum has a region in which magnetic fields in different directions are alternately formed along a circumferential direction of the rotary drum,
The magnetic separation method for a steelmaking slag according to claim 1, wherein the liquid is sprayed on a surface of the rotary drum on which at least one of the magnetic fields in the different directions is formed.   The magnetic separation method for steelmaking slag according to claim 1, wherein the liquid is sprayed from an inclined direction to a tangent of the rotary drum including a position where the liquid is sprayed.   The magnetic separation method for steelmaking slag according to any one of claims 1 to 3, further comprising a step of spraying a gas after spraying the liquid on the surface of the rotary drum. A rotary drum on which a magnetic field is formed on at least a part of the surface; and
Arranged in this order in the direction of rotation of the rotary drum,
Nozzle for injecting a slurry containing steel slag in the form of particles crushed or pulverized on the surface,
A slurry tank for bringing a slurry containing steelmaking slag into contact with the rotary drum; and, of the surface of the rotary drum, spraying a liquid on a region where the magnetic field is formed, and rotating along the surface of the rotary drum. Moving, a liquid spraying unit for removing liquid components and non-magnetic particles contained in the slurry,
A magnetic separator for steelmaking slag, comprising: The rotary drum has a region where magnetic fields in different directions are formed along a circumferential direction of the rotary drum,
The liquid spraying unit sprays the liquid to a region on the surface of the rotary drum where at least one of the magnetic fields in the different direction is formed.
A magnetic separator for steelmaking slag according to claim 5.   The magnetic separation apparatus for steelmaking slag according to claim 5, wherein the liquid spraying unit sprays the liquid from an inclined direction with respect to a tangent line of the rotary drum including a position where the liquid is sprayed. Having a gas blowing unit for blowing gas to the surface of the rotary drum,
The magnetic separator for steelmaking slag according to claim 5.

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