JP2011215065A - Method and microwell for magnetic force sorting of fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for magnetic force sorting of fine particles which increase the efficiency of analytical precision or separative work after separating magnetized fine particles from non-magnetized ones and also can sort magnetic force of the fine particles group within the desirable magnetic range, and also to provide a microwell for magnetic force sorting to be used in this method.SOLUTION: The magnetic force sorting method is to hold volatile liquid containing both magnetized fine particles magnetized by applying magnetic force and non-magnetized fine particles non-magnetized by applying magnetic force into a flat-bottomed hollow made on the microwell, sorting the fine particles group into magnetized fine particles and non-magnetized ones. A tabular spacer made of non-magnetic material mounted on tip of the magnet is immersed in the volatile liquid and the fine particles group is sandwiched between the spacer and bottom face of the hollow. Under such conditions, depth of the volatile liquid in the hollow is defined as the level in which the spacer is immersed in the volatile liquid while the magnet is not immersed, allowing magnetized fine particles to be absorbed onto the magnet through the spacer.

Description

  The present invention relates to a magnetic force selection method for magnetically selecting fine particles to be evaluated for magnetic properties and a magnetic force selection microwell used for the method.

  A sample composed of fine particle groups is separated into a magnetized particle group (hereinafter also referred to as “magnetized particle group”) and a non-magnetized particle group (hereinafter also referred to as “non-magnetized particle group”). Thus, methods for recovering each particle group are widely practiced industrially, including analysis of biological samples. At this time, by adding a volatile liquid to the sample and performing magnetic separation (wet separation), the influence of static electricity on the sample can be removed, and since a volatile liquid is added, If the sample after the magnetic selection is simply left, the added liquid is volatilized and removed naturally, so that there is an advantage that the operation becomes easy. Therefore, wet separation is used to separate the magnetized particle group and the non-magnetized particle group.

  As described above, as a method for separating the magnetized particle group and the non-magnetized particle group by wet separation, for example, in Patent Document 1, in a microwell holding a liquid containing sample particles, a microwell structural material is used. The sample particles are magnetized and magnetized particles (magnetized particles) remain in the microwell, and the non-magnetized particles are sucked out together with the surrounding liquid with a pipette or the like. Is disclosed.

  Further, in Patent Document 2, when magnetically sorting particles in a microwell, a magnet is provided outside the pipette that sucks the particles from the microwell together with the liquid, and the magnetic force acts on the particles sucked into the pipette from the outside of the pipette. After discharging the non-magnetized particles in the pipette together with the liquid, erase the magnetic force on the pipette, and then re-suction the fresh liquid containing no particles with the pipette. A method for discharging out of a pipette is disclosed.

  Further, in Patent Document 3, when magnetically sorting particles in a microwell, the pipette itself that sucks out the particles from the microwell together with the liquid is magnetized, and only the magnetic particles are left in the pipette. A method of erasing and discharging magnetized particles is disclosed.

  Further, Patent Document 4 discloses a method of magnetically sorting particles by inserting a pin into a pipette and magnetizing or demagnetizing it instead of magnetizing the pipette as in Patent Document 3. ing.

  For example, in Patent Document 5, in place of a microwell, a number of test tube “tubes” are connected and arranged, and extraction for magnetic force sorting of particles exhibiting the same function as each well of the microwell. An apparatus is disclosed.

  Furthermore, for example, Patent Document 6 discloses a biochemical reaction cell that is intended for an aqueous solution and that exhibits the same function as each individual well of a microwell.

JP-A-10-332567 JP 11-132934 A JP 2006-126061 A JP 2007-108624 A JP 2003-93918 A JP-A-11-146784

  However, the techniques described in Patent Documents 1 to 4 require a step of sucking out particles together with liquid with a pipette when separating the magnetized particle group and the non-magnetized particle group. In such a process, it is necessary to suspend the sample particles in a larger amount of liquid than the particles. Therefore, in the case of sample particles that are soluble in the liquid, since the sample particles are dissolved in the liquid during the operation, the physical and chemical properties of the sample may be impaired, and the analysis accuracy after separation may be adversely affected.

  In addition, the above technique requires a step of separately collecting the magnetized particles remaining in the microwell. In particular, particles having a particle size of about 50 μm or less have a significantly larger specific surface area than coarse particles, and are likely to adhere to the microwell or pipette wall, and the particles in the microwell are completely removed. In addition, a great deal of labor is required. Therefore, the process and equipment for separating the magnetized particle group and the non-magnetized particle group are complicated, and the efficiency of the separation work is low. For example, in order to reuse the microwell, a cleaning process is required, and in order to collect the magnetic particles, equipment and a process for removing the magnetization of the microwell are generally required.

  In the techniques of Patent Documents 2 to 4, the arrangement of the magnets and the structure of the pipette are geometrically irregular. Even for the same particle, various forces (magnetic force) applied to the particle depending on the position in the pipette. , Gravity, viscous force from liquid, reaction force at the time of pipette wall contact, etc. In this case, it is possible in principle to magnetize all magnetized particles by using a remarkably strong magnet. However, particles other than antiferromagnetism generate some magnetization in the magnetic field. Even particles that are desired to be separated from magnetized particles as magnetic particles can be magnetized in the magnet, which is not preferable.

  Furthermore, in the techniques of Patent Documents 2 to 4, when the pipette is a disposable method in order to omit the pipette cleaning step, some of the magnetized particles are discarded while adhering to the pipette, This is not preferable because the amount of collected sample decreases.

  In the techniques of Patent Documents 5 and 6, the same problems as in Patent Documents 1 to 4 occur.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to improve analysis accuracy after separation of magnetized fine particles and non-magnetized fine particles and efficiency of separation work, and to achieve It is an object of the present invention to provide a magnetic force sorting method for fine particles capable of magnetically sorting fine particle groups in the range of the magnetic field and a magnetic well sorting microwell used therefor.

  As a result of intensive research to solve the above problems, the present inventors have added a volatile liquid and volatilized when separating into magnetized fine particles and non-magnetized fine particles by magnetic force (wet separation). By using a microwell for holding a sexual liquid and a magnet having a spacer attached to the tip, and further controlling the depth of the volatile liquid held in the microwell to a predetermined depth, The analysis accuracy after separation of magnetized fine particles and non-magnetized fine particles and the efficiency of the separation work are improved, and it has been found that fine particles can be magnetically selected within a desired magnetic range, and the present invention is completed based on this knowledge. It came to do.

  That is, according to the present invention, a group of fine particles composed of magnetized fine particles that are magnetized by applying a magnetic force and non-magnetized fine particles that are not magnetized are provided in the well of the microwell provided with a recess having a flat bottom surface. A magnetic force sorting method for holding a volatile liquid contained therein and sorting the group of fine particles into the magnetized fine particles and the non-magnetized fine particles, which is made of a non-magnetic material attached to the tip of a magnet and has a flat plate shape. A spacer is immersed in the volatile liquid, and the fine particle group is sandwiched between the spacer and the bottom surface of the depression, and the depth of the volatile liquid in the depression is determined by the spacer. A magnetizing step of adsorbing the magnetized fine particles to the magnet through the spacer under a condition that the magnet is immersed in a liquid and having a predetermined depth at which the magnet is not immersed in the volatile liquid; and Above There is provided a magnetic force separation method including a magnetic separation step that separates the magnetic fine particles separated from the microwell and adsorbed to the magnet via the spacer, and the non-magnetic fine particles remaining in the recess. Is done.

  In the magnetic force sorting method, the magnetizing step includes a first step of spraying the fine particle group on the bottom of the recess, and the volatile liquid so that the volatile liquid has the predetermined depth in the recess. A second step of injecting the liquid into the recess, and immersing the spacer in the volatile liquid in the recess to bring the magnet closer to the fine particle group, and the magnetic fine particle through the spacer. A third step of attracting the magnet to the magnet, wherein the magnetic force separation step separates the magnet from the bottom surface of the recess and magnetizes the magnetized fine particles adhering to the spacer outside the microwell. A fourth step of placing on the substrate for fine particles, and a fifth step of separating the magnet from the substrate for magnetic fine particles and placing at least the magnetic fine particles on the substrate for magnetic fine particles. And the extent, may be included.

  In the magnetic force sorting method, as the microwell, an assembly-type magnetic force sorting microwell including a plurality of members including a substrate for non-magnetic fine particles constituting the bottom surface of the depression is used, and after the fifth step. Removing the volatile liquid by disassembling the magnetic selection microwell and removing the non-magnetic fine particle substrate, and leaving or heating the non-magnetic fine particle substrate; And a seventh step.

  In the fifth step, the magnet is detached from the spacer on the substrate for magnetized fine particles, and the magnetized fine particles attached to the spacer are placed on the substrate for non-magnetized fine particles together with the spacer. You may do it.

  It is preferable that an average magnetic flux density on the surface on the fine particle group side of the spacer in the third step is 0.1 T or more and 0.4 T or less.

  In the magnetic force sorting method, the fine particle group may be made of falling dust generated from an iron manufacturing plant by a blast furnace method.

  Further, according to the present invention, there is provided a magnetic well selecting microwell used in the magnetic force selecting method described above, which is a flat non-magnetic fine particle substrate formed of a transparent and non-magnetic material, and the non-adhesive. A flat support plate made of a non-magnetic material that supports a substrate for magnetic fine particles, and an elasticity that does not dissolve in the volatile liquid and has a hardness measured by a durometer of A30 or more and A65 or less Comprising a gasket having one or more through-holes and a flat pressing plate made of a non-magnetic material and having one or more through-holes, the support plate, In a state where the substrate for magnetic fine particles, the gasket, and the pressing plate are stacked and fastened in order from below, the volatile liquid is discharged by the through hole of the gasket and the through hole of the pressing plate. To hold Depression of is formed, the microwell is provided for magnetic separation.

  In the magnetic sorting microwell, the volatile liquid includes at least one alcohol selected from the group consisting of methanol, ethanol and propanol.

  In the magnetic sorting microwell, it is preferable that the elastic body is any one of butyl rubber, EPM, and EPDM.

  In the magnetic well selecting microwell, the fastening method is preferably band fastening.

  In the magnetic sorting microwell, the non-magnetizing fine particle substrate may be a glass plate.

  According to the present invention, when performing wet separation using a microwell having a dent for holding a volatile liquid, the volatile property is maintained in a state in which the particle group is sandwiched between the bottom of the dent and the spacer. The depth of the liquid is set to such a depth that only the spacer is immersed without the magnet being immersed, thereby improving the analysis accuracy after separation of the magnetized fine particles and the non-magnetic fine particles and the efficiency of the separation work. In addition, the fine particle group can be magnetically selected within a desired magnetic range.

It is explanatory drawing which shows the specific example of the magnetic force selection method of the microparticles | fine-particles which concern on suitable embodiment of this invention. It is explanatory drawing which shows the rough relationship between the magnetization and the brightness in each dust type of the dust fall derived from the steelmaking plant by a blast furnace method. It is a flowchart which shows the flow of the process in the magnetic force selection method which concerns on the embodiment. It is explanatory drawing which shows the specific example of the magnetic force selection method of the microparticles | fine-particles which concern on suitable embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the whole structure of the assembly-type magnetic sorting microwell based on suitable embodiment of this invention, (a) is a top view, (b) is the magnetic sorting microwell shown to (a). It is AA sectional drawing. It is a graph which shows an example of the relationship between the hardness and SP value (solubility parameter) of various rubbers and elastomers. It is explanatory drawing which shows an example of the magnetization state of the particle | grains at the time of performing wet separation on a flat board | substrate. It is explanatory drawing which shows an example of the magnetization state of the particle | grains at the time of performing wet separation using an excessive amount of volatile liquid.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Outline and superiority of the present invention]
The present invention relates to a pretreatment for analyzing a sample used for various industrial analyses. Specifically, the present invention relates to a magnetic force selection method for selecting a group of fine particles immersed in a volatile liquid into magnetized fine particles that are magnetized by applying a magnetic force and non-magnetized fine particles that are not magnetized. It is the microwell for magnetic selection used for a method. Before describing such preferred embodiments of the present invention, first, the problems in wet separation, the technical idea underlying the present invention for solving this problem, and the superiority of the present invention explain.

(Problems of wet separation)
As described above, in the techniques described in Patent Documents 1 to 4, it is necessary to suspend the sample particles in a large amount of liquid compared to the particles. Therefore, in the case of sample particles that are soluble in the liquid, the sample particles dissolve in the liquid during the operation, so that the physical and chemical properties of the sample may be impaired and the analysis accuracy after separation may be adversely affected. Occurs.

  Further, in the techniques of Patent Documents 1 to 4, since the fine particles to be separated by magnetic force can move freely in the liquid, the positional relationship with the magnet, in particular, the distance from the magnet is greatly different for each particle. Become. In general, as the distance from the magnet surface increases, the magnetic flux density in the space decreases sharply. Therefore, in the techniques of Patent Documents 1 to 4, even particles having the same magnetic characteristics depend on the position in the liquid. There is a possibility that magnetized and non-magnetized particles may be generated, and there is a problem that the accuracy of magnetic separation is not high (the magnetized particles cannot be distinguished from the non-magnetized particles).

(Basic technical idea and superiority of the present invention)
In order to solve this problem, the present inventor uses a microwell or the like that holds the particle group to place the particle group between the flat surface of the bottom part of the microwell that holds the particle group and the flat spacer. Further, by arranging the plane of the tip of the magnet on the back side of the spacer, the difference in the distance between the surface of the magnet and the fine particles can be determined for each particle of the largest diameter in the fine particles to be separated. A method has been devised to keep the particle size below.

  This point will be described in more detail with reference to FIG. FIG. 1 is an explanatory diagram showing a specific example of a magnetic force sorting method for fine particles according to a preferred embodiment of the present invention.

  As shown in FIG. 1, in the magnetic force sorting method according to the present invention, a volatile liquid L is added to magnetize fine particles Pm to magnetize a magnet 11 and non-magnetized fine particles Pn to be magnetized. Perform wet separation to separate. At this time, a microwell 100 or the like provided with a depression 105 for holding the volatile liquid L is used. As the microwell 100, a commercially available one can be used, but in the present invention, the one in which the bottom of the recess 105 is a flat surface is used. The shape of the recess 105 is not particularly limited, but is preferably substantially circular because the magnet 11 and the spacer 13 used for magnetic force selection can be easily inserted into and extracted from the recess 105. However, the shape of the depression 105 may be a regular polygon, a rectangle, an ellipse, or the like if there is a reason for processing convenience of the depression 105. In the magnetic force selection method according to the present invention, a magnetic force is applied to the fine particle group using a magnet having a flat-plate spacer 13 attached to the tip. Details of the magnet 11 and the spacer 13 will be described later.

  Using the microwell 100 and the magnet 11 as described above, first, as shown in FIG. 1 (a), fine particles composed of magnetized particles Pm and non-magnetized particles Pn in the recesses 105 of the microwell 100. The volatile liquid L containing the group is held, and in this state, the spacer 13 is immersed in the volatile liquid L, and the fine particle group is sandwiched between the lower surface of the spacer 13 and the bottom surface of the recess 105. At this time, in the fine particle group, the particle having the largest particle size comes into contact with both the lower surface of the spacer 13 and the bottom surface of the recess 105, and the other particles are between the lower surface of the spacer 13 and the bottom surface of the recess 105. It exists in the liquid L.

  In the present invention, at this time, only the spacer 13 is immersed in the volatile liquid L, and the magnet 11 is not immersed in the liquid L. That is, the liquid level of the volatile liquid L held in the depression 105 is located between the lower surface and the upper surface of the spacer 13.

  Next, as shown in FIG. 1B, the magnetized particles Pm attracted to the magnet 11 through the spacer 13 are pulled up from the liquid L together with the magnet 11 and the spacer 13. At this time, the non-magnetized particles Pn remain in the volatile liquid L.

  Further, as shown in FIG. 1C, the magnetized particles Pm attached to the spacers 13 are placed on the substrate 10 (substrate for magnetized particles) outside the microwell 100 and the magnets 11 are separated. Thus, the magnetic particles Pm and the non-magnetic particles Pn can be magnetically selected.

  Further, at the time of magnetic separation, the diameter of the magnet 11 (in the case of a cylindrical magnet) is at least 10 times or more, more preferably 100 times or more the particle diameter of the particle having the largest size in the fine particle group to be separated. Thus, the magnetic flux density difference due to the difference in distance from the magnet 11 between the spacer 13 and the bottom surface of the depression 105 (that is, the range corresponding to the particle diameter of the largest particle in the fine particle group to be separated). The inventor has found that is at a negligible level. For example, consider the magnetic flux density in the vicinity of a magnet when it is assumed that spherical particles having a diameter of 0.3 mm are magnetized on the end face of a cylindrical magnet. When the magnet diameter is 1 mm (that is, about 3.33 times the particle to be measured), the magnetic flux density at the farthest point of the particle to the magnet is about 48% of the value at the nearest point (the particle contacts the magnet surface). The effect of particle size on magnetism cannot be ignored. On the other hand, when the magnet diameter is 3 mm (that is, about 10 times the particle to be measured), the magnetic flux density at the farthest point of the particle to the magnet is greatly improved to about 80% of the value at the nearest point. Further, when the magnet diameter is 30 mm (that is, about 100 times the particle to be measured), the magnetic flux density at the farthest point of the particle to the magnet is about 98% of the value at the nearest point, and the particle diameter with respect to the magnetization. The effect of is almost lost. Based on this principle, the magnet 11 having a diameter at least 10 times larger than the particle diameter of the largest particle in the group of fine particles to be separated is applied by the method shown in FIG. As long as particles exist between the bottom surface, almost constant magnetic force can be exerted on any particle, and particles having the same magnetic characteristics can be discriminated as magnetized or non-magnetized. .

  Further, when performing magnetic separation (wet separation) in a wet manner, when the magnet 11 is immersed in the liquid L added to the microwell 100, the liquid L adheres directly to the magnetic particles Pm, and the magnetic particles Pm are removed. Since it takes labor to detach from the magnet 11, it is not preferable. Therefore, in the magnetic field sorting method according to the present invention, only the spacer 13 is in the recess 105 of the microwell 100 using the above-described microwell 100 and the magnet 11 having the nonmagnetic material spacer 13 attached to the tip. The depth of the volatile liquid L including the fine particle group to be analyzed is set to a depth at which the magnet 11 is immersed in the liquid L and the magnet 11 is not immersed in the liquid L.

  Here, if only a small amount of liquid for performing magnetic separation is supplied into the microwell, the risk of the liquid overflowing on the spacer (separation plate) can be avoided. However, in such a state, coarse particles are exposed from the liquid surface and are blocked by the top of the coarse particles that have been exposed, so that the spacer cannot contact the liquid. This is the same state as the positional relationship among particles, spacers, and liquid when wet separation is performed without using a microwell, as shown in FIG. When the volatile liquid L is added directly to the group of fine particles dispersed on the substrate 1 without using a microwell, the liquid L spreads around the surroundings regardless of the amount of the supplied liquid, and the liquid film becomes thin. Therefore, when a relatively coarse particle is to be magnetically separated by a wet method, the state shown in FIG. In this case, coarse particles in contact with the spacer 13 among the magnetized particles Pm can be magnetized, but it is difficult for the small-diameter magnetized particles Pm existing below the liquid surface to reach the spacer 13 and magnetize. It is. This is because when a small-diameter particle reaches the spacer 13, it must pass through the liquid surface (gas-liquid interface). If the particles are highly lyophilic (ie, highly wettable) particles, the magnet 11 must overcome the strong surface tension that acts around the particles on the liquid surface in order to leave the liquid surface. Therefore, even magnetized particles cannot be easily separated from the liquid L. Thus, when the spacer 13 is not in contact with the liquid L, there arises a problem that the magnetization rate of the magnetized particles Pm decreases. On the other hand, if the spacer 13 is in contact with the liquid L, the surface tension as described above is not applied to the particles, so that the magnetized particles Pm can easily reach the spacer 13 and be magnetized.

  Further, when lifting the magnetized particles from the spacer 13 for separating the magnetic force, the liquid L itself is separated and partly remains in the spacer 13 (when the spacer 13 made of a lyophilic material is used). Since the magnetized magnetic particles Pm remain in the residual liquid, the magnetic particles Pm do not need to be detached from the liquid L at this time, and the magnetization of the magnetic particles Pm is maintained. Therefore, the contact of the spacer 13 with the liquid L is an essential condition in the wet magnetic separation. In the magnetic field sorting method according to the present invention, since the liquid L is held in the microwell 100, it is much easier to raise the liquid level than in the case where the microwell is not used as shown in FIG. This is advantageous with respect to the contact between the liquid 13 and the liquid L.

  On the other hand, if the amount of liquid supplied into the microwell is excessive, the liquid overflows on the spacer as described above, which is not preferable. That is, as shown in FIG. 8A, the distance between the bottom surface of the recess 105 ′ provided in the microwell 100 ′ and the spacer 13 is set larger than the particle diameter of the largest particle in the fine particle group to be separated. In this case, it is possible to avoid the liquid L from overflowing on the spacer 13. However, this situation is not preferable in terms of the accuracy of magnetic separation because the magnetic flux density distribution in the liquid L is generated as described above. For example, in FIG. 8, as the fine particle group, three types of particles having the same magnetic properties of magnetization and differing only in density and particle size, specifically, coarse particles having a density lower than that of the liquid L, coarse particles 2 shows an example including magnetized particles having a density higher than that of the liquid L and fine particles having a level capable of being suspended in the liquid L. When magnetic separation is performed on such a group of fine particles, as shown in FIG. 8B, all and part of coarse and low density magnetized particles located near the spacer 13 having a high magnetic flux density. Only the fine particles are magnetized and separated and removed from the liquid L, and the remaining particles remain in the liquid L. Originally, since particles having the same magnetic characteristics are used, all particles should be magnetized. Therefore, when the amount of liquid supplied into the microwell is excessive as in the magnetic separation method shown in the example of FIG. 8, it can be evaluated that the separation accuracy is low.

  Therefore, according to the magnetic separation method according to the present invention, the microwell is used, and the amount of the volatile liquid supplied to the microwell is sandwiched between the bottom surface of the recess provided in the microwell and the spacer. In a state where the spacer is in contact with the liquid, and the liquid does not overflow on the spacer, the magnetized particles can be magnetized with a high probability regardless of the particle diameter. Can be discriminated.

  Furthermore, in the magnetic separation method according to the present invention, the microwell is constructed in an assembling structure for the convenience of particle analysis after wet magnetic separation, the microwell is disassembled after wet magnetic separation, and the hollow portion after decomposition is separated. It is preferable to use a magnetic selection microwell that can be used as it is as a particle sample for analysis. By using such an assembly-type microwell, the sample remaining on the bottom of the dent, which is necessary when using an integrated microwell, is collected separately, and a new particle sample for analysis is produced. The trouble of having to do it can be omitted.

  Therefore, in a preferred embodiment of the present invention, the magnetic sorting microwell used for wet separation is an assembly type, and as one of the components constituting this microwell, various analyzes after magnetic sorting (for example, particle images) It is also possible to provide a substrate that can be used as it is as a substrate for non-magnetic fine particles during processing measurement. More specifically, the magnetic selection microwell according to a preferred embodiment of the present invention includes a support plate for supporting a substrate for non-magnetized fine particles from below (opposite the surface on which the fine particles are placed); A substrate for non-magnetized fine particles, a gasket having a through-hole for forming a well (depression), and a pressing plate having a through-hole for forming a well and holding the gasket from above are sequentially arranged from below. They are stacked and fastened. If a microwell having such a structure is used, magnetic separation is performed using the microwell, then the microwell is disassembled, the substrate for non-magnetic particles is taken out, and the liquid added to the microparticles is removed. If volatilization is removed, this substrate can be used as a sample for analysis as it is.

<Problems that arise when microwells are assembled>
By the way, in order to make a microwell into an assembly type, there has been a big problem as described below.

1) Problems when trying to ensure a seal First, there is a problem when trying to ensure a seal. When the microwell is an assembly type, a seal is necessary to hold the volatile liquid added to the fine particle group in the microwell. Here, since the volatile liquid to be added to the fine particle group is required to have wettability with the fine particles, in general, a liquid having a low surface tension and viscosity such as lower alcohols such as methanol, ethanol, and propanol is selected. Is done. Such a lower alcohol has a very low surface tension and viscosity, making it difficult to seal compared to water and oil. Such a seal of a volatile liquid such as a lower alcohol can be used temporarily if an elastic material such as rubber is used as a seal material (gasket) and the seal material is strongly fastened to other parts.

  However, a strong fastening force such as a bolt fastening by a set mechanical force is necessary to fasten in this way, but if the support plate or the holding plate is deformed by such a strong fastening force, it is sandwiched between them. The substrate for non-magnetized fine particles (mainly glass plates etc. are used) may be damaged, so the rigidity of the microwell itself is ensured by, for example, making the support plate and holding plate extremely thick. There is a need. Therefore, there is a problem that the microwell becomes larger and assembly and disassembly are not easy.

2) Problem of component elution (bleed) from sealing material Second, there is a problem of component elution (bleed) from the sealing material. Lower alcohol used as a volatile liquid added to the fine particle group destroys the cross-linked structure in the sealing material (elastic material such as rubber) in contact with it and is usually contained in the elastic material. The softener component is eluted. Many of the components eluted in this way are non-volatile, and this non-volatile elution component remains on the substrate for non-magnetized particles together with the non-magnetized fine particles after magnetic separation. The remaining elution component is not preferable because it contaminates the sample for analysis and becomes a disturbance factor for the particle image at the time of particle image processing measurement, for example, and hinders analysis after magnetic separation.

  In addition, when the microwell is fastened with a strong fastening force in order to improve the sealing performance by the sealing material, the amount of deformation of the elastic material used as the sealing material increases due to this fastening force. Small cracks are likely to occur on the end face of the elastic material corresponding to the contacting portion. When the lower alcohol is infiltrated into the minute cracks generated in this manner, bleeding is promoted and the cracks progress and increase, and the durability of the elastic material is significantly reduced. Therefore, it is not preferable to fasten the microwell with a strong fastening force from the viewpoint of preventing the bleeding from being promoted.

  As described above, since there is a trade-off between the problem of trying to perform a secure seal and the problem of specimen contamination due to bleeding from the elastic body, a method for solving both problems has not been known. Assembling-type microwells have not been put to practical use.

  Therefore, as a result of earnestly examining the means for solving the above-mentioned problems, the present inventor can perform a reliable seal even with a weak fastening force and has a high bleed resistance (bleed suppression effect) and a sealing method. I found. As a result, a magnetic well sorting microwell that can be easily assembled and disassembled was completed.

  By using the magnetic selection microwell according to the present invention as described above, the degree of freedom of wet magnetic selection is improved, that is, the wet separation can be performed using the microwell. Problems associated with adding a volatile liquid onto the substrate can be avoided.

(Application to the identification of dust types of falling dust from steel plants)
Moreover, as a particle group used as the object of magnetic separation using the microwell for magnetic separation of the present invention, for example, dust falling from an iron manufacturing plant by a blast furnace method can be included. As a countermeasure against problems such as fouling vehicles entering the steel plant premises caused by such dustfall, it is considered to be effective to identify the dust species of the collected dustfall.

  Details of the definition of dustfall and specific examples of dust species will be described later, but in order to identify the dust species of dust fall from steel plants, it is necessary to separate the different dust types. As described above, the magnetic field selection method using the magnetic force selection microwell of the present invention is effective. Among the dust species included in the dust fall from the steel plant, soot from iron ore, soot from converter slag, etc. are fine particles having ferromagnetic or strong paramagnetism. The present invention can be applied to such magnetic selection of fine particles having ferromagnetism or strong paramagnetism. According to the present invention, fine particles having ferromagnetism or strong paramagnetism (magnetization fine particles), Alternatively, fine particles that do not have strong paramagnetism (non-magnetic fine particles) can be easily selected. Therefore, if the magnetic sorting microwell and the magnetic sorting method according to the present invention are applied, among the falling dusts derived from the steel plant, a group of fine particles consisting of at least dust derived from iron ore, dust from converter slag, etc. And other groups (for example, dust derived from coal or coke, dust derived from blast furnace slag, etc.).

  Here, with reference to FIG. 2, an advantage in the case where the present invention is applied to the specification of the dust type of the falling dust derived from the steel plant will be described. FIG. 2 is an explanatory diagram showing a schematic relationship between magnetism and lightness in each dust type of dust falling from a steelmaking plant by the blast furnace method.

  In general, the falling dust derived from the steelmaking plant by the blast furnace method is mainly composed of coal dust including coal and coke, iron dust including iron ore, sintered ore, iron oxide powder, blast furnace granulated slag, blast furnace It is classified into four types of soot, including blast furnace slag dust including slow-cooled slag, and steelmaking slag dust including converter slag and hot metal pretreatment slag.

  Of these four types of soot dust, blast furnace slag soot dust and steelmaking slag soot dust are normally white particles with high brightness (light colored particles), and coal dusts and iron soot dusts have black brightness. Because it is a low particle (dark particle), the blast furnace slag system is used to identify the level of brightness of individual dust particles by applying image processing to images taken using a low-magnification optical microscope. It is possible to discriminate between a soot type consisting of soot and steelmaking slag-type soot and a soot type consisting of coal-based soot and iron-based soot.

  However, it is not possible to discriminate between particles having the same level of brightness, for example, discrimination between blast furnace slag dust and steelmaking slag dust, only by classifying such bright particles and dark particles. That is, as described above, the image processing is simply performed on the photographed image, and the classification based only on the brightness level is too comprehensive, and the soot species of the falling dust derived from the steelmaking plant by the blast furnace method (and the source of the falling dust) Since it cannot be specified, the utility is low.

  Therefore, in order to identify the dust type of the dust falling from the steelmaking plant by the blast furnace method (hereinafter, sometimes referred to as “iron-making dust falling dust”), the present inventor only uses the brightness level of the dust particles. We focused on the presence or absence of magnetism. As a result, the present inventor can define the dust characteristics by the combination of the brightness level and the presence or absence of magnetism, and based on this dust characteristics, the dust type of the falling dust derived from the ironmaking plant by the blast furnace method can be determined. I found out that it can be identified. In more detail, the present inventor, as shown in FIG. 2, shows the dust type of the dust fall derived from iron making that cannot be determined by simply image-processing a low-magnification optical microscope image, as shown in FIG. It has been found that it is possible to discriminate among four types of coal dust, iron dust, blast furnace slag dust, and steelmaking slag dust.

  The magnetism in the present invention means the property of magnetizing (being magnetized and attracted to the magnet) by applying a predetermined magnetic force to the target dust particles, In addition, the falling dust derived from the blast furnace method steel plant is classified into a magnetic falling dust that is magnetized by applying a magnetic force and a non-magnetic falling dust that is not magnetized even when a magnetic force is applied. Each of falling dust and non-magnetic falling dust is classified into light particles and dark particles according to the brightness.

  Specifically, coal-based soot has low lightness (dark color) and non-magnetic non-magnetized dark particles, and iron-based dust has low lightness (in dark color) magnetized dark magnetized particles, blast furnace slag Soot dust is classified as non-magnetic non-magnetized light particles with high brightness (light color), and steelmaking slag dust is classified as magnetized magnetized light-colored particles with high brightness (light color). be able to.

  As described above, according to the knowledge found by the present inventor, it becomes possible to specify the dust type of the iron-making-derived dustfall according to the dust characteristics, but at this time, as a method for discriminating the lightness Can be separately performed by visual classification or image processing particle measurement.

[Magnetic Selection Method According to Preferred Embodiment of the Present Invention]
The outline of the present invention and the superiority over the prior art have been described above. Subsequently, the magnetic force selection method according to the present embodiment will be described in detail with reference to FIGS. 1, 3, and 4. FIG. 3 is a flowchart showing a flow of processing in the magnetic force selection method according to the present embodiment. FIG. 4 is an explanatory diagram showing a specific example of the magnetic force selection method according to the present embodiment.

  In the magnetic force selection method according to the present embodiment, a fine particle group consisting of magnetized fine particles that are magnetized by applying a magnetic force and non-magnetized fine particles that are not magnetized in a recess of a microwell provided with a recess having a flat bottom surface. Is a magnetic force selection method for holding a volatile liquid containing and sorting the held fine particles into magnetized fine particles and non-magnetized fine particles, and includes a magnetization step and a magnetic force separation step.

  First, in the magnetic separation step, a flat spacer made of a non-magnetic material attached to the tip of the magnet is immersed in a volatile liquid, and a group of fine particles is sandwiched between the spacer and the bottom of the recess. The magnetized fine particles are passed through the spacer under the condition that the depth of the volatile liquid in the recess is a predetermined depth in which the spacer is immersed in the volatile liquid and the magnet is not immersed in the volatile liquid. Specifically, it includes the first to third steps described below.

  Second, the magnetic force separation step is a step of separating the magnet from the microwell and separating the magnetized fine particles adsorbed on the magnet through the spacer and the non-magnetized fine particles remaining in the recess. Includes the fourth and fifth steps described below.

(First step)
First, in the first step, as shown in FIG. 3 and FIG. 1 (a), a group of fine particles (for example, in a steelworks) is formed on the flat surface at the bottom of the recess 105 of the magnetic sorting microwell 100. The dust particles collected at the specific place are sprayed (S101). At this time, the amount of spraying is adjusted so that the particles do not contact each other as much as possible, and further, a group of fine particles sprayed with a spatula or the like is appropriately arranged. The number of fine particles dispersed on the bottom of the depression 105 is not particularly limited, but it is preferable to use at least 100 fine particles as an analysis sample in order to evaluate the influence of sample variation.

  In addition, when using falling dust derived from an ironmaking plant as a specimen, the falling dust is usually coarse particles having a diameter of 10 μm or more. Therefore, when spraying the falling dust particles, the dust particles fall in the atmosphere. Free fall can be used. Specifically, for example, the collected dust particles can be sprinkled with a soot and dropped onto the substrate from above, whereby the dust particles can be dispersed on the substrate.

(Second step)
Next, in the second step, as shown in FIGS. 3 and 1A, the volatile liquid L is injected into the depression 105 so that the volatile liquid L has a predetermined depth in the depression 105. (S103).

<Types of volatile liquid L>
The volatile liquid L added to the fine particle group is not particularly limited. For example, lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, petroleum oils such as kerosene and gasoline, toluene and hexane For example, cyclic hydrocarbons such as water, water, and the like can be used. Here, when the range of the particle type to be analyzed is known in advance, the liquid L having a high affinity with the particle type may be used. For example, if the microparticles to be analyzed are highly hydrophilic particles, a highly polar liquid (for example, methanol or the like) becomes a liquid L having a high affinity, and if the microparticles to be analyzed are highly lipophilic particles, the polarity is high. A liquid having a low affinity (for example, hexane or the like) becomes a liquid L having a high affinity.

  On the other hand, when the particle type to be analyzed is unknown or when a plurality of particle types having greatly different polarities are targeted, ethanol, propanol or the like that shows both hydrophilicity and lipophilicity should be used as the volatile liquid L. That's fine.

  However, when the solubility of the microparticles to be analyzed in the volatile liquid L is extremely large, in order to maintain the physical properties and shape of the microparticles, the miscibility of the liquid L and the microparticles is slightly sacrificed. A liquid L that is slightly different from the polarity may be used.

  Further, the miscibility between the liquid L and the fine particles is generally determined by the magnitude of the viscosity and the surface tension, and the use of the liquid L having a small viscosity and the surface tension may cause the difference between the fine particles to be analyzed and the liquid L. It is preferable from the viewpoint of mixing.

  In particular, ethanol or propanol is suitable when the dust falling from the steelmaking plant by the blast furnace method is to be analyzed. For example, when water, which is an inexpensive and safe liquid type, is used as the liquid L, there arises a problem that slag particles, which are one type of dust fallen dust derived from an ironmaking plant, are dissolved in water. Therefore, it is easier for ethanol and propanol to disperse the particles in the liquid than for water. Further, ethanol and propanol are advantageous in that they are both miscible with fine particles in a wide polar range because they have both hydrophilicity and lipophilicity.

<Addition amount of volatile liquid L>
The above-mentioned predetermined depth, that is, the depth of the liquid L in the depression 105 is deeper than the depth at which the fine particles having the maximum particle diameter are immersed in the volatile liquid L among the fine particles assumed to be included in the fine particle group. Must be (liquid depth condition 1). Preferably, the depth of the liquid L is set to a depth of 1.2 times or more of the assumed maximum particle diameter of the fine particles.

  Examples of a method for estimating the maximum particle size of the fine particles at this time include the following three methods. First, there is a method of investigating only the particle size distribution (particularly on the coarse particle side) by laser particle measurement or the like in advance. Second, there is a method in which fine particles as a sample are sieved in advance to remove coarse particles having a predetermined size or more. Third, there is a method of using knowledge from the survey results of past samples collected under similar conditions.

  The depth of the liquid L in the depression 105 is determined by the magnet 11 when the spacer 13 is immersed in the volatile liquid L in the depression 105 until the spacer 13 comes into contact with the largest particle among the fine particles. It is necessary to have a depth that does not contact the volatile liquid L (liquid depth condition 2). In other words, the height of the liquid surface of the liquid L is such that the lower surface of the spacer 13 (the surface on the side in contact with the fine particle group) is in contact with the liquid L until the surface of the fine particles on the flat surface at the bottom of the recess 105 contacts. When dipped in, the position needs to be lower than the position of the upper surface of the spacer 13 (the contact surface with the tip surface of the magnet 11).

  The maximum depth of the liquid L can be confirmed by injecting the liquid L into the recess 105 and testing it in advance without including the fine particle group. In addition, a fixed spacer fixed to the magnet is provided as the spacer 13 at the tip of the magnet 11, and if a detachable spacer is further provided at the tip of the fixed spacer, the fixed spacer is fixed. The thickness of both the spacer and the detachable spacer may be considered as the thickness of the spacer 13 described above.

  In order to satisfy both the liquid depth condition 1 and the liquid depth condition 2 described above, the spacer 13 is immersed in the volatile liquid L, and the fine particle group is sandwiched between the spacer 13 and the flat surface at the bottom of the recess 105. In this state, the depth of the volatile liquid L in the recess 105 is set so that the spacer 13 is immersed in the volatile liquid L and the magnet 11 is not immersed in the volatile liquid L. Good. Specifically, the thickness of the spacer 13 and the ratio of the diameter of the spacer 13 to the recess 105 (in the case of a shape other than a circle, the equivalent circle diameter) may be set as appropriate. If the spacer 13 is sufficiently thick, the liquid L does not reach the upper surface of the spacer 13. Further, if the diameter of the recess 105 is sufficiently larger than the diameter of the spacer 13, the liquid L hardly reaches the upper surface of the spacer 13. However, if any of the conditions is an extreme setting, the accuracy of magnetic selection is deteriorated. Therefore, the necessary and sufficient thickness of the spacer 13 and the diameter ratio between the spacer 13 and the recess 105 should be set.

  In the present embodiment, the first step and the second step are separate steps, but these steps may be performed simultaneously. That is, when the fine particle group is sprayed on the bottom of the recess 105, the liquid L (suspension) containing the fine particle group is suspended after the fine particle group is suspended in the volatile liquid L, instead of being sprayed directly. You may inject | pour into the hollow 105. FIG.

(Third step)
Next, in the third step, as shown in FIG. 3 and FIG. 1A, the spacers 13 are immersed in the volatile liquid L in the depression 105, so that the magnet 11 is brought into a group of particles (magnetized particles Pm). Then, the magnetic particles Pm are attracted (magnetized) to the magnet 11 through the spacer 13 (S105). Therefore, the magnetic fine particles Pm adhere to the lower surface of the spacer 13 (the surface opposite to the side where the magnet 11 is present). In addition, when the magnet 11 is an electromagnet, it is necessary to magnetize the magnet 11 before making the magnet 11 approach a particle group.

  Here, when the magnet 11 is brought close to the fine particle group, the flat surface at the tip of the magnet 11 is made the bottom surface of the depression 105 (the microwell is an assembly type) in order to minimize the contact and overlap of the magnetic fine particles Pm. In this case, it is preferable that the surface be parallel to the surface of the non-magnetic fine particle substrate 210 described later. Further, the contact time between the magnetized fine particles Pm and the spacer 13 when adsorbing the magnetized fine particles Pm to the magnet 11 may be, for example, 1 second or more.

<Shape and dimensions of magnet 11>
The magnet 11 used in the present embodiment is provided with a spacer 13 at the tip (the side in contact with the fine particle group). The magnet 11 only needs to have a flat shape at the tip, and as the magnet 11, for example, a cylinder type or a prismatic type can be used. Moreover, in order to ensure the contact property with the fine particles dispersed on the bottom of the recess 105 and the uniformity of the magnetic force applied to each fine particle, the cross-sectional area of the tip of the magnet 11 is preferably 0.1 cm ² or more. .

<Type of magnet 11>
As a kind of the magnet 11, either a permanent magnet or an electromagnet may be used, but if it is a permanent magnet, a neodymium magnet, a samarium cobalt magnet, a ferrite magnet, etc. can be used. Among these, neodymium magnets and samarium cobalt magnets are effective when not only ferromagnetic materials but also relatively strong paramagnetic materials are included as analysis target fine particles, and ferrite magnets are strong paramagnetic materials as analysis target fine particles. It is effective when including only. Further, when an electromagnet is used as the magnet 11, it is effective to use an electromagnet when a relatively weak paramagnetic material is included as a fine particle to be separated using a magnetic force that cannot be achieved by a permanent magnet.

  Further, when using the magnetic field sorting method according to the present embodiment in order to specify the dust type of the falling dust derived from the ironmaking plant by the blast furnace method, the magnet 11 has an average magnetic flux density on the surface of the spacer 13 on the fine particle group side. Is preferably 0.1 T or more and 0.4 T or less. That is, as a condition for causing the magnet 11 to adsorb the iron dust and the steelmaking slag dust that are one of the typical dust types of the dust falling from the steel plant, the magnetic flux density when applying the magnetic force to the dust falling is: It is preferable that it is 0.1 T or more on at least the surface of the spacer 13 on the fine particle group side. On the other hand, even if the magnetic force applied to the falling dust is too strong, the coal-based dust is adsorbed to the magnet in the same way as the iron-based dust due to the iron contained in a small amount in the coal-based dust, which is one of the typical dust types. Therefore, as a condition for avoiding such a phenomenon, it is preferable that the magnetic flux density when the magnetic force is applied to the falling dust is 0.4 T or less on the surface of the spacer 13 on the fine particle group side. is there.

  As a specific example of the magnet 11 that can realize the preferable magnetic flux density range as described above, for example, there is an electromagnet that can realize a magnetic flux density in the range of 0.1T to 0.4T. As the permanent magnet, a neodymium magnet, a samarium cobalt magnet, or the like having a magnetic force with a magnetic flux density in the range of 0.1 T to 0.4 T can be used. Note that a ferrite magnet, which is a typical permanent magnet, has a weak magnetic force, and is not suitable as a magnet for use in magnetic separation when specifying the type of dust that falls from a steel plant.

<Spacer 13>
The main role of the spacer 13 is to make the magnetic force on the surface of the spacer 13 uniform. For example, when a ring-shaped magnet is used, the magnetic force in the vicinity of the central portion of the magnet 11 corresponding to the hole in the center of the ring is generally small, while the magnetic force in the vicinity of the peripheral portion of the magnet 11 is generally large. The gradient of the magnetic flux density is increased, and it is difficult to uniformly attach the magnetized fine particles to the magnet 11. On the other hand, when the group of fine particles dispersed on the bottom surface of the depression 105 moves away from the magnet 11 by a certain distance, the magnetic force below the central portion of the magnet 11 becomes the same magnetic force as that on the horizontal plane. In particular, when a thin magnet having a small cross-sectional area at the tip is used as the magnet 11, the gradient of the magnetic flux density in the horizontal plane decreases as the distance from the tip of the magnet 11 becomes uniform. Therefore, by providing the spacer 13 at the tip of the magnet 11, it is possible to prevent fine particles from approaching the tip of the magnet 11 more than necessary.

  The material of the spacer 13 is not particularly limited as long as it is non-magnetic, but for example, a plastic plate (elastic resin such as rubber or vinyl chloride) or a glass plate may be used. it can. Also, the shape of the spacer 15 is not particularly limited, but for example, a substantially ring-shaped one can be used. Further, the thickness of the spacer 13 is not particularly limited, but if it is too thin, the above-described effect of uniforming the magnetic force in the horizontal plane may not be obtained sufficiently. If it is too thick, the magnetic force on the lower surface of the spacer 13 is weakened. Therefore, it is preferably about 0.3 mm to 3 mm.

  In this embodiment, two types of spacers, a fixed spacer and a detachable spacer, may be used as the spacer 13. In this case, for example, a plastic plate (a synthetic resin having elasticity such as rubber or vinyl chloride) can be used as the fixed spacer, and a glass plate can be used as the removable spacer. As a method for fixing each spacer, for example, a fixed spacer is bonded and fixed to the tip of the magnet 11, and the removable spacer is attracted and fixed to the lower surface of the fixed spacer by a suction force such as a vacuum pump. Also good.

(Fourth process)
Next, in the fourth step, as shown in FIG. 3 and FIGS. 1B and 1C, the magnet 11 is placed on the bottom surface of the depression 105 (if the microwell is an assembly type, non-magnetization described later). The magnetic fine particles Pm separated from the fine particle substrate 210) and attached to the spacers 13 are placed on the substrate (the magnetic particle substrate 10) outside the microwell 100 (S107). Here, when the magnet 11 is separated from the bottom surface of the recess 105, the magnet 11 is pulled up above the recess 105 while the spacer 13 is attached to the tip of the magnet 11. At this time, the fine particles remaining on the bottom surface of the depression 105 are samples of non-magnetic fine particles Pn (see FIG. 1B). Further, when the magnetized fine particles Pm are placed on the magnetized fine particle substrate 10, the magnet 11 on which the magnetized fine particles Pm are attracted is lowered toward the magnetized fine particle substrate 10, and the magnetized fine particles Pm are attached to the magnetized fine particles Pm. What is necessary is just to contact the board | substrate 10 for magnetic fine particles.

(Fifth step)
Next, in the fifth step, as shown in FIG. 3 and FIG. 1 (c), the magnet 11 is separated from the magnetized particle substrate 10, and at least the magnetized fine particles Pm are placed on the magnetized particle substrate 10. (S109). That is, in the fifth step, the magnet 11 is separated from the magnetized fine particles Pm. Specifically, when the magnet 11 is a permanent magnet such as a neodymium magnet, the spacer 13 is fixed on the substrate 2, the magnet 11 is detached from the spacer 13, and only the magnet 11 is pulled up, and magnetized under the spacer 13. The fine particles Pm are left. By doing so, the magnetized fine particles Pm can be pressed from above by the gravity of the spacer 13, and the magnetized fine particles Pm can be separated from the magnet 11 which is a permanent magnet. In order to fix the spacer 13, the spacer 13 may be simply placed on the magnetic particle substrate 10 using the gravity of the spacer 13. On the other hand, when the magnet 11 is an electromagnet, the current flowing through the electromagnet is turned off (in a device having a degaussing function, the current is turned off after supplying the demagnetizing power), and the magnet 11 is pulled up as it is, and the magnetized fine particles Pm Is left on the substrate 2. When the magnet 11 is an electromagnet, the magnet 11 may be pulled up with the spacer 13 attached, and as in the case of a permanent magnet, the magnet 11 is detached from the spacer 13 and only the magnet 11 is pulled up. Also good.

(Sixth step)
In the magnetic force sorting method according to the present embodiment, an assembly-type magnetic force sorting microwell (for example, a microwell 200 to be described later) composed of a plurality of members including a substrate for non-magnetized fine particles constituting the bottom surface of the depression as the microwell. After the fifth step, as shown in FIGS. 3 and 4A, the sixth step of disassembling the magnetic force selection microwell 200 and taking out the non-magnetic particle substrate 210 is further performed. (S111). As a method of disassembling the magnetic sorting microwell 200 at this time, for example, when the fastening method of each component of the microwell 200 is bolt fastening, the bolt may be loosened. Can be cut.

(Seventh step)
In the magnetic field sorting method according to the present embodiment, after the fifth step, as shown in FIGS. 3 and 4B, the non-magnetizing particle substrate 110 is left or heated, whereby the non-magnetizing particle-use substrate 110 is used. A seventh step of removing the volatile liquid L adhering to the substrate 110 and the non-magnetized particles Pn may be further performed (S113). After the seventh step, only the non-magnetizing particles Pn (and possibly the spacers 13) remain on the non-magnetizing particle substrate 110.

<Method for removing volatile liquid L>
As a method for removing the volatile liquid L, a method in which the volatile liquid L is volatilized and removed by leaving the non-magnetized particle substrate 110 is also applicable. However, if the liquid L takes a long time to volatilize, bleed described later is likely to occur. Therefore, in the present embodiment, the seventh step is performed in parallel with the sixth step or more than the sixth step. You may go before. In this case, it is preferable to heat the non-magnetizable particle substrate 110 to dry and remove the volatile liquid L in a short time. For example, a heater may be used for heating the non-magnetic particle substrate 110 at this time. The heating temperature is preferably up to about 60 ° C. so as not to cause deterioration of the rubber.

(About the analysis target)
As a first example of the fine particles (specimen) to be subjected to the magnetic separation method according to the present embodiment, high-purity ceramic particles produced by crushing with a crusher such as a ball mill made of stainless steel (SUS304, etc.) can be cited. It is done. The ceramic grains usually contain impurity particles mainly composed of stainless steel grains by peeling off from the crusher during crushing operations. For example, for a strong magnet such as a neodymium magnet, stainless steel such as SUS304 is magnetized, but ceramic particles are not magnetized. Therefore, when high-purity ceramic grains are to be analyzed, if a neodymium magnet or the like is used as a magnet for magnetic selection, ceramic grains and impurity particles mainly composed of stainless steel grains in the ceramic grains are used. Magnetic sorting is possible. If this is utilized, the concentration of the impurity particles in the ceramic grains can be measured.

  Further, as described above, as a second example of the fine particles to be subjected to the magnetic force sorting method according to the present embodiment, there is dust falling from an iron manufacturing plant by a blast furnace method. Such falling dust has a problem of fouling a vehicle entering the steel plant premises, and measures against such a problem are required. To that end, technology is needed to identify the source of the falling dust collected at a specific point, and as a method for identifying the source of the falling dust, the dust type of the collected dust is identified. It is thought that it is effective.

  Here, the falling dust means a particle having a relatively large diameter (approximately φ10 μm or more) that can be averagely settled in the atmosphere among solid particles floating in the atmosphere. In addition, the “dust type” in the present invention is not particularly limited, but refers to the type of soot classified according to the above-mentioned source of dustfall, components, and the like. For example, when classifying by source, soot species are: iron ore-derived soot generated from iron ore raw material yard, coal-derived soot generated from coal raw material yard, blast furnace slag derived from blast furnace slag It is classified as dust from the converter slag generated from the converter.

  According to such classification, as dust types of dust fall from steelmaking plants by the blast furnace method, mainly (1) coal-based soot such as coal and coke whose main component is carbon and (2) main component Ferrous dust such as iron ore and sintered ore, iron oxide powder (for example, steelmaking dust) common to iron oxides, and (3) impurities from molten raw materials that are common in silicon oxide and calcium oxide. Blast furnace slag dust such as granulated blast furnace slag and blast furnace slow-cooled slag, and (4) the main component is common to silicon oxide, calcium oxide and iron oxide, and There are steelmaking slag dusts such as converter slag and hot metal pretreatment slag, which have common processes in that impurities are separated from a molten raw material as a liquid or solid. The soot species that can be dustfall in modern steelmaking plants using the blast furnace method can be almost covered by the coal-based soot, iron-based soot, blast furnace slag-based soot and steel-making slag-based soot described above.

  In order to specify the dust type of the falling dust from the steelmaking plant as described above, it is necessary to separate the different dust types, but the magnetic separation device and magnetic separation method of the present invention are effective as this separation method. It is. Of the four types of dust described above, iron dust and steelmaking slag dust are ferromagnetic or strong paramagnetic (for example, magnetized to a magnet having a magnetic flux density of about 0.1 T to 0.4 T). Fine particles. The magnetic force sorting method according to the present embodiment can be applied to such magnetic force sorting of fine particles having ferromagnetic or strong paramagnetism. According to the present embodiment, fine particles having ferromagnetic or strong paramagnetic properties (attachment) Magnetic fine particles) and fine particles having no ferromagnetism or strong paramagnetism (non-magnetic fine particles) can be easily selected. Therefore, if the magnetic separation method according to the present embodiment is applied, among the falling dust derived from the ironmaking plant, at least a fine particle group composed of iron-based dust and steelmaking slag-based dust, and coal-based dust and blast furnace slag-based dust. It can be separated into fine particle groups.

  In general, blast furnace slag dust and steelmaking slag dust are white particles with high brightness (light colored particles), and coal dust and iron dust are black particles with low brightness (dark colored particles). Therefore, by performing image processing on images taken using a low-magnification optical microscope and discriminating the level of brightness of individual dust particles, it is possible to distinguish between iron-based dust and steelmaking slag-based dust, as well as coal-based dust. Can be distinguished from blast furnace slag dust.

  However, the fine particles to be subjected to the magnetic force selection method according to the present embodiment are not limited to the above two examples, and using a predetermined magnet, fine particles that are magnetized on the magnet and fine particles that are not magnetized. Any fine particle group can be used as long as it is a fine particle group separated into two.

[Magnetic sorting microwell according to preferred embodiment of the present invention]
Although the magnetic field selection method according to the present invention has been described above, an assembly-type magnetic force selection microwell used for the fine particle magnetic field selection method including the sixth and seventh steps described above with reference to FIG. Will be described in detail. 5A and 5B are explanatory views showing the overall configuration of the assembly-type magnetic force sorting microwell according to this embodiment. FIG. 5A is a top view, and FIG. 5B is the magnetic force sorting microwell shown in FIG. It is AA sectional drawing.

  The assembly-type magnetic sorting microwell 200 according to the present embodiment sorts a group of fine particles immersed in a volatile liquid into magnetized fine particles that are magnetized by applying a magnetic force and non-magnetized fine particles that are not magnetized. Microwell for sorting. Specifically, as shown in FIG. 5, the magnetic force selection microwell 200 mainly includes a non-magnetic fine particle substrate 210, a support plate 220, a gasket 230, a pressing plate 240, and a fastening band 250. Prepare for.

(Non-magnetic fine particle substrate 210)
The non-magnetic fine particle substrate 210 is an example of a first substrate according to the present embodiment. The material of the non-magnetizable fine particle substrate 210 is not particularly limited as long as it is a transparent and non-magnetizable material. However, a material that is hard and smooth and has little elution by a chemical solution is preferable. Specifically, a hard synthetic resin such as glass, acrylic, or vinyl chloride can be used as the material for the non-magnetizable fine particle substrate 210, and when observation from the back surface is not required during particle analysis. An opaque material, for example, a processed non-metallic material may be used. Among these, the non-magnetic fine particle substrate 210 is most preferably made of glass from the viewpoint of processing into a transparent, non-magnetized, hard, flat and smooth plate, and little elution by a chemical solution. preferable.

  The shape of the non-magnetic fine particle substrate 210 is not particularly limited as long as it has a flat plate shape. For example, the shape in the horizontal plane may be a rectangle, a circle, an ellipse, a polygon, or the like. it can. The thickness of the non-magnetic fine particle substrate 210 is preferably 1 mm or more and 20 mm or less. If the thickness of the non-magnetic fine particle substrate 210 is less than 1 mm, there is a possibility that the rigidity for holding the analysis sample (particle group) cannot be secured. On the other hand, when the non-magnetizable fine particle substrate 210 is made of glass or the like, the color is visually recognized. Therefore, when the non-magnetizable fine particle substrate 210 is extremely thick, The thickness of the non-magnetizable fine particle substrate 210 is preferably 20 mm or less because there is a possibility of misidentifying the color of the particles in image processing measurement or the like.

(Support plate 220)
The support plate 220 supports the non-magnetizable fine particle substrate 210 from below (the side opposite to the surface on which the fine particles are placed). The material of the support plate 220 must be a non-magnetic material, and is preferably a material that is tough and has a low permanent set. Further, the material of the support plate 220 is flat and smooth at least on the surface in contact with the non-magnetic fine particle substrate 210, and the non-magnetic fine particle substrate 210 is contaminated from the surface (contamination due to peeling of rust or the like). It is preferable that the material is difficult. From the above viewpoint, as the material of the non-magnetizable fine particle substrate 210, for example, aluminum, aluminum alloy, copper, brass, bronze, titanium, or the like can be used.

Further, the shape of the support plate 220 is not particularly limited as long as it has a flat plate shape. For example, the shape in the horizontal plane may be a rectangle, a circle, an ellipse, a polygon, or the like. As the size of the support plate 220, the smaller the horizontal plane area, the easier it is to ensure the rigidity of the support plate 220, which is preferable. However, when a plurality of samples (particle groups) are subjected to magnetic separation simultaneously, a plate having a large horizontal plane area can be used. From the above viewpoint, specifically, the horizontal plane area of the support plate 220 is preferably 1 cm ² or more and 1 m ² or less. Further, the thickness of the support plate 220 is preferably 1 mm or more from the viewpoint of ensuring the rigidity of the support plate 220. However, if the support plate 220 is extremely thick, the magnetic well sorting microwell 200 is enlarged and assembled. And dismantling is no longer easy. Therefore, the thickness of the support plate 220 is preferably 100 mm or less.

(Gasket 230)
The gasket 230 is formed of an elastic body such as rubber or elastomer. Specifically, in the present embodiment, an elastic body that does not dissolve in the volatile liquid added to the fine particle group and has a hardness measured with a durometer of A30 or more and A65 or less is used as the material of the gasket 230. .

  Here, in this embodiment, “does not dissolve in a volatile liquid” does not mean that the elastic body forming the gasket 230 should not dissolve in a volatile liquid at all, and an elution component such as a softener. However, there is no problem as long as the solubility is within a range that does not adversely affect the subsequent analysis (for example, particle image processing measurement) (eg, the color of the particles cannot be discriminated due to the elution component mainly composed of oil). In addition, as a volatile liquid in this embodiment, at least 1 or more types of alcohol (lower alcohol) selected from the group which consists of methanol, ethanol, and propanol can be used, for example.

  The durometer hardness defined in JIS K6253 is used as the hardness of the elastic body according to the present embodiment. As a durometer used in this durometer hardness measurement, a type A durometer for medium hardness (A20 to A90) may be used.

<Material of gasket 230>
Hereinafter, a material suitable as the material of the gasket 230 will be described in detail with reference to FIG. FIG. 6 is a graph showing an example of the relationship between the hardness (durometer hardness) and SP value (solubility parameter) of various rubbers and elastomers. FIG. 6 shows the SP value of ethanol as an example of the volatile liquid according to the present embodiment for reference.

  FIG. 6 shows various rubbers and elastomers. Among these, from the viewpoint of bleed resistance, considering that the SP value of lower alcohol is high, a material having a small SP value is resistant to lower alcohol. Excellent bleeding. That is, if the material has an SP value that has a large difference from the SP value of the lower alcohol, since the solubility in the lower alcohol is small, there is a possibility that bleeding of components such as a softening agent in the elastic body can be suppressed. As the material having such a low SP value, for example, butyl rubber, EPM, EPDM, silicon rubber, fluorine rubber, and the like exist in the material shown in FIG.

  However, among these materials, silicon rubber is not suitable because it has a low solubility in lower alcohols, but the crosslinked structure in the polymer is easily broken and deteriorates severely, resulting in poor bleeding. Fluorine rubber is not suitable for single-component systems because of its low chemical resistance to lower alcohols.

  Moreover, even if it is butyl rubber, EPM, EPDM, even if a foaming raw material is a closed-cell type, it is not suitable. The bubble wall in the foamable material is easily damaged by the fastening force when fastening each component of the magnetic sorting microwell 200 and the jig at the time of magnetic sorting, and the sealing property and bleed property are not good. This is because there is not.

  From the viewpoint of sealing performance, a material having a low elastic modulus is suitable because it is easy to ensure sealing performance even with a weak fastening force, and generally it is difficult to cause cracks at the end face even if it is greatly deformed. Here, the fastening force is preferably 3 kgf or more and 30 kgf or less in terms of, for example, conversion when band fastening is adopted as the fastening method. This is because the fastening force can be easily fastened manually or with a small electric tool or the like. Further, as described above, if the fastening force is too strong, the gasket 230 is damaged and the bleed property is deteriorated. However, as described later, if the fastening force is within this range, both the sealing property and the bleed resistance can be achieved. This is because the material of the gasket 230 exists.

  The elastic condition of the material of the gasket 230 for satisfying the sealing performance of the lower alcohol with the fastening force in the above range is A65 or less in terms of hardness. If the hardness of the elastic body exceeds A65, the amount of deformation of the elastic body becomes small, so that the sealing performance is lowered. Conversely, if the sealing performance is to be secured, the fastening force becomes too large, which is not preferable. Further, the lower the hardness is, the better the sealing performance is. However, in order to obtain a low-hardness elastic body, it is generally necessary to mix a large amount of softener (such as fats and oils) into the elastic material. For this reason, the softening agent is easily eluted in a volatile liquid such as a lower alcohol, and the bleeding property is deteriorated. From this point of view, the gasket 230 is made of A30 or more in terms of hardness. For example, some binary or higher fluororubbers are highly resistant to lower alcohols, but the hardness is generally as high as A80 or higher, which is not preferable from the viewpoint of sealing properties. On the other hand, in order to reduce the hardness of fluororubber, a large amount of softener (such as oils and fats) must be mixed in the rubber material. Therefore, low hardness fluororubber deteriorates the bleed resistance, The material of the gasket 230 is not suitable.

  As a result of the above studies, butyl rubber, EPM, and EPDM have a low SP value, excellent bleed resistance to volatile liquids such as lower alcohols, and satisfy the conditions of hardness of 30 A or more and 65 A or less. It was found that both sealability and excellent bleed resistance can be achieved. That is, the material of the gasket 230 is particularly preferably any one of butyl rubber, EPM, and EPDM.

  Both EPM and EPDM are ethylene-propylene rubber-like copolymers called ethylene-propylene rubber (EPDM is a terpolymer further containing a diene as a third component), and details are specified in JIS K6397. Has been.

<Shape and dimensions of gasket 230>
In addition, a through hole 231 is formed in the gasket 230. The through-hole 231 is a portion corresponding to a depression (well) formed in the magnetic force selection microwell 200 when fastened. Examples of a method for forming the through-hole 231 include a method of punching a portion corresponding to a depression in an elastic plate having an outer shape substantially the same shape as the non-magnetic particle substrate 210. In addition, an annular elastic plate is used as the gasket 230, and a recess is formed between the central opening (corresponding to the through hole 231) of the annular plate and the surface of the non-magnetizable particle substrate 210 exposed in the central opening. You may make it comprise.

  The number of through holes 231 may be one or plural. If there are a plurality of through holes 231, a plurality of depressions are formed, and a plurality of samples can be subjected to magnetic force sorting at the same time, so that the processing productivity is high.

  The shape of the through hole 231 is preferably substantially circular because it is easy to insert and remove the magnet and spacer used for magnetic selection into the recess. However, if there is a reason for processing of the through hole 231, the shape of the through hole 231 may be a regular polygon, a rectangle, an ellipse, or the like.

  The thickness of the gasket 230 is preferably 0.1 mm or greater and 10 mm or less, and more preferably 1 mm or greater and 3 mm or less. If the thickness of the gasket 230 is less than 0.1 mm, the sealing performance may not be ensured. On the other hand, when the thickness of the gasket 230 exceeds 10 mm, it may be difficult to insert / insert the magnet used for magnetic force selection or the recess of the spacer.

(Presser plate 240)
As a material of the pressing plate 240, a material that can be used for the support plate 220 is preferable. That is, the material of the pressing plate 240 must be a non-magnetizable material, and is preferably a tough material with a small permanent set. Moreover, it is preferable that the material of the pressing plate 240 is a material that is flat and smooth at least on the surface in contact with the gasket 230, and hardly contaminates the gasket 230 from the surface (contamination due to peeling of rust or the like). From the above viewpoint, as the material of the pressing plate 240, for example, aluminum, aluminum alloy, copper, brass, bronze, titanium, or the like can be used.

  A through hole 241 is formed in the presser plate 240. When the through-hole 241 is fastened, the through-hole 241 and the through-hole 231 of the gasket 230 become a portion corresponding to a depression (well) formed in the magnetic sorting microwell 200. Examples of the method for forming the through hole 241 include a method of punching a portion corresponding to a depression in a plate having an outer shape substantially the same as that of the support plate 220.

  The number of through holes 241 may be one or plural. If there are a plurality of through holes 241, a plurality of depressions are formed, and a plurality of samples can be subjected to magnetic force sorting at the same time, and the processing productivity is high. However, from the viewpoint of increasing the productivity of the process, it is preferable that the through hole 231 and the through hole 241 are formed at a position where the through hole 231 and the through hole 241 communicate with each other at the time of fastening.

  The shape of the through-hole 241 is preferably substantially the same shape as the through-hole 231 of the gasket 230, and it is easy to insert / insert the magnet and spacer used for magnetic force selection into the recess, and the sealing property of the gasket 230 In view of this point, it is preferable to have a substantially circular shape. However, if there is a reason for convenience in processing the through hole 241, the shape of the through hole 241 may be a regular polygon, a rectangle, an ellipse, or the like.

  In addition, the thickness of the pressing plate 240 is approximately the same as the thickness of the support plate 220 or the rigidity of the presser plate 240 is reduced more easily than the thickness of the support plate 220 because the through hole 241 is included. A thicker one is preferred.

(Dent)
Further, in the magnetic sorting microwell 200 according to the present embodiment, the above-described support plate 220, non-magnetic fine particle substrate 210, gasket 230, and pressing plate 240 are stacked and fastened in order from the bottom. Thus, the through hole 231 of the gasket 230 and the through hole 241 of the holding plate 240 form a recess 205 for holding a volatile liquid. The shape and dimensions of the recess are determined by the shapes and dimensions of the through hole 231 and the through hole 241, the dimensions of the gasket 230 and the pressing plate 240, and the like.

  The bottom surface of the recess 205 is configured as a portion of the surface of the non-magnetizable fine particle substrate 210 that is opened by the through hole 231 and the through hole 241. By injecting a volatile liquid containing a group of fine particles into the depression 205, the non-magnetized fine particles are left as they are on the bottom surface of the depression 205, that is, the surface of the substrate 210 for non-magnetized particles, after magnetic separation. become. Therefore, by disassembling the magnetic selection microwell 200 after magnetic separation, the non-magnetic particle substrate 210 on which non-magnetic fine particles are placed is used as it is for subsequent analysis (for example, particle image processing measurement). be able to.

(Fastening method)
In addition, the method of fastening the support plate 220, the non-magnetizable fine particle substrate 210, the gasket 230, and the pressing plate 240 is not particularly limited, and examples thereof include the following bolt fastening and band fastening. . However, as described above, if the fastening force is too strong, the microwell becomes large and the assembly and disassembly is not easy, and the amount of deformation of the elastic body used as the gasket 230 increases. There is a problem that minute cracks are likely to occur on the end face. Therefore, as a fastening method in the present embodiment, band fastening capable of providing an appropriate fastening force is preferable. Hereinafter, each fastening method will be described.

<Bolt fastening>
In the case of bolt fastening, for example, the support plate 220 and the pressing plate 240 are set to be slightly larger than the non-magnetic particle substrate 210 and the gasket 230, and the bolts are formed in the margins around the support plate 220 and the pressing plate 240. A plurality of holes are drilled and the support plate 220 and the pressing plate 240 are passed through and fastened with bolts and nuts. Although this method can surely seal, the structure of the microwell is complicated, and assembly and disassembly are not easy.

<Band fastening>
In the case of band fastening, the outer peripheral portion of the support plate 220, the non-magnetizable particle substrate 210, the gasket 230, and the pressing plate 240 laminated in this order is fastened with a fastening band 250 made of synthetic resin such as nylon. As the fastening band 250, a commercially available cable tie for electric wires may be used.

  Further, the fastening location is a position avoiding the location where the through hole 231 and the through hole 241 are formed so as not to block the depression 205 formed after fastening, for example, both ends of the magnetic sorting microwell 200, , Any position between the through hole 231 and the through hole 241.

  As for the fastening method, it is preferable to use a cable tie for electric wires or a welding type (semi) automatic fastening machine as a simple fastening method. As described above, since an extremely strong fastening force is not necessary, even when an automatic fastening machine is used, for example, a small desktop type having a fastening force of about 10 kgf is suitable. Thereby, it can be set as the range (3 kgf or more and 30 kgf or less) of the fastening force mentioned above. On the other hand, as a disassembly method, the fastening band 250 may be cut with a blade or the like. As described above, the magnetic selection microwell 200 according to the present embodiment can be easily assembled and disassembled and the structure can be simplified by fastening the band.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  Next, the present invention will be described more specifically with reference to examples.

Example 1
As Example 1, impurity particles in alumina fine particles produced by crushing with a SUS ball mill were separated (magnetic force sorting), and various analyzes were performed.

<Magnetic separator>
1) Magnet, Spacer As a magnetic force sorting device for magnetically sorting the magnetized fine particles and the non-magnetized fine particles, a device having a detachable spacer attached to the tip of the magnet was used. As the magnet, a cylindrical electromagnet having a diameter of 25 mm was used. The magnetic flux density on the lower surface of this magnet spacer (detachable spacer) was 0.5T. Further, as the spacer, a glass circular plate having a diameter of 30 mm and a thickness of 2 mm was used, and this was fixed to the lower surface of the magnet by attracting it using the suction force when evacuated by a vacuum pump.

2) Microwell for magnetic force sorting As the microwell for magnetic force sorting, an integrated microwell is used. This microwell is made of glass, the diameter of the circular cross section is 40 mm, and the bottom of the well (dent) is flat. The number of wells was one.

3) Magnetic Particle Substrate As the magnetic particle substrate, a 60 mm square and 3 mm thick glass plate was used.

<Sample>
As a sample for analysis, 1 mg of high-purity alumina particles pulverized with a ball mill made of SUS304 was used. The maximum particle size of the alumina particles was 50 μm.

<Magnetic selection method>
Next, the third to fifth steps in the magnetic force selection method according to the above-described embodiment were performed (see FIGS. 1, 3 and 4) to separate the magnetic fine particles into non-magnetic fine particles. As a volatile liquid, 0.5 ml of ethanol was used.

<Particle image processing measurement>
Next, a commercially available trinocular stereomicroscope (objective lens magnification: 0.5 times), a commercially available ring light source (white light) in a lens barrel, a commercially available monochrome digital camera (CCD 6 million pixels, pixel dimensions are 3 [mu] m square) was mounted on the camera mounting opening. Next, only a sample of the magnetized particles was placed on the stage of the microscope, and images were taken as predetermined illumination conditions, camera apertures, and exposure conditions to obtain captured images of the magnetized particles.

  At this time, the magnification of the microscope was adjusted so that the actual size of the particle to be measured was imaged to the same size on the CCD element of the camera. Further, the particles to be recognized by the microscope were particles having a size of φ10 μm or more because the alumina particles were coarse. In the present embodiment, the size of the particles corresponds to 9 pixels or more of the CCD.

  For the captured image of the magnetized particles obtained as described above, commercially available particle image processing software IMAGRPRO PLUS VER. 5 was used for particle image processing measurement. At this time, the measurement target was the center position of each particle, the circle equivalent diameter of each particle, and the average brightness of each particle (the average value of the brightness of each pixel existing in the pixel region recognized as a particle).

  Specifically, using a predetermined lightness threshold value T1, a pixel region having a lightness less than the lightness threshold value T1 is specified as a region where particles are present, and each pixel existing in the pixel region is specified. The center position, circle equivalent diameter, and volume of each particle present in the captured image of the magnetized particles were calculated based on the positions of the magnetic particles, and the calculation results were recorded.

  As a result of the above operation, it was found that particles corresponding to 0.8% in volume ratio with respect to the entire target particles for magnetic force sorting are magnetized particles. As a result of further component analysis of this magnetized particle sample with an ICP emission analyzer, it was found that the main components were Fe, Cr, and Ni, and the peeled particles from the ball mill were the main components of impurities.

  From this result, it was found that the impurities in the high-purity alumina particles can be efficiently separated by the magnetic separation method according to the present invention by using the magnetic separation method according to the present invention.

(Example 2)
As Example 2, various types of analysis were performed by separating the dust fall from the steelmaking plant by the blast furnace method for each dust type (magnetic force sorting).

<Magnetic separator>
1) Magnet, Spacer As a magnetic force sorting device for magnetically sorting the magnetically fine particles and the non-magnetic fine particles, a device in which a fixed spacer and a detachable spacer are attached to the tip of the magnet was used. As the magnet, a cylindrical neodymium magnet having an outer diameter of 13 mm, an inner diameter of 4 mm, and a height of 10 mm was used. The magnetic flux density on the lower surface of this magnet spacer (detachable spacer) was 0.4T. Further, as a fixed spacer, a butyl rubber spacer having an outer diameter of 15 mm, an inner diameter of 10 mm, and a thickness of 2 mm was used, and this was adhered and fixed to the tip of the magnet. In addition, as a detachable spacer, a glass spacer having a diameter of 15 mm and a thickness of 0.2 mm is used, and this is adsorbed to the lower surface of the fixed spacer by using a suction force when evacuated by a vacuum pump. Fixed.

2) Microwell for magnetic selection As the microwell for magnetic selection, an assembled type was used. For each component, a 40 mm square, 5 mm thick duralumin plate is used as the support plate, and a 40 mm square, 3 mm thick float glass plate is used as the non-magnetized particle substrate. Is made of butyl rubber with an outer diameter of 40 mm square and a thickness of 2 mm, and a through-hole with a diameter of 20 mm formed at the center. The holding plate has an outer diameter of 40 mm square and a thickness of 5 mm and a diameter of 20 mm at the center. The thing made from duralumin in which the through-hole of this was formed was used. In addition, as a fastening method of these parts, a nylon cable tie having a length of 250 mm was used and two ends of the microwell were fastened with a manual tool (commercial cable tie fastening tool) (fastening force was 10 kgf).

3) Magnetized Particle Substrate As the magnetized particle substrate, the same shape, size and material as the non-magnetized particle substrate were used.

<Sample collection method>
First, as a sample for analysis, dust falling was collected for one week with a commercially available deposit gauge in the premises of an iron manufacturing plant by the blast furnace method, and 100 mg of dust falling (average diameter 20 μm) was obtained. After this dustfall is air-dried indoors for 3 days, 300 μg (maximum particle size: 150 μm) of the total amount of dustfall is suspended in 0.2 ml of ethanol, and all of the suspension is suspended with a micropipette. Dropped on top.

<Magnetic selection method>
Next, the third to seventh steps in the magnetic force selection method according to the above-described embodiment were performed (see FIGS. 4 to 6), and separated into magnetic fine particles and non-magnetic fine particles. The microwell was disassembled in the sixth step by cutting the cable tie. As a method for removing the volatile liquid in the seventh step, the non-magnetic particle substrate was heated with an electric heater, and ethanol remaining on the substrate was removed by evaporation in 10 minutes.

<Particle image processing measurement>
Next, a commercially available trinocular stereomicroscope (objective lens magnification: 0.5 times), a commercially available ring light source (white light) in a lens barrel, a commercially available monochrome digital camera (CCD 6 million pixels, pixel dimensions are 3 [mu] m square) was mounted on the camera mounting opening. Next, a sample of magnetized fallen dust and a sample of non-magnetized fallen dust are placed on the stage of the microscope, and the illumination conditions are the same, and the camera aperture and exposure are taken in order under the same conditions. A dust image and a non-magnetized dust image were obtained.

  At this time, the magnification of the microscope was adjusted so that the actual size of the particle to be measured was imaged to the same size on the CCD element of the camera. In addition, the particles to be recognized with a microscope are particles with a size of φ10 μm or more because they are dust falling and the particles are coarse. In the present embodiment, the size of the particles corresponds to 9 pixels or more of the CCD.

  For the magnetized dust image and the non-magnetized dust image obtained as described above, commercially available particle image processing software IMAGRPRO PLUS VER. 5 was used for particle image processing measurement. At this time, the measurement target was the center position of each particle, the circle equivalent diameter of each particle, and the average brightness of each particle (the average value of the brightness of each pixel existing in the pixel region recognized as a particle).

  Specifically, using a predetermined lightness threshold value T1, a pixel region having a lightness less than the lightness threshold value T1 is specified as a region where particles are present, and each pixel existing in the pixel region is specified. Based on the position and brightness, the center position, average brightness, and circle equivalent diameter of each particle present in each of the magnetized dust image and the non-magnetized dust image were calculated, and the calculation results were recorded.

  Next, the average brightness of each particle calculated as described above is compared with a predetermined brightness threshold value T2 (> T1), and each particle in the image is classified into a dark color particle and a light color particle. did.

  Furthermore, using the circle equivalent diameter of each particle calculated as described above, each particle is classified according to a particle size category for which boundary values have been defined in advance, and the particle composition ratio for each particle size category is represented by a lightness category (dark color and light color). For each particle).

  As a result of the above operation, it was found that 70% by volume of the total collected dust fall was magnetic fine particles, and these magnetic fine particles were mainly iron-based dust fall. Further, it was found that 30% by volume of the collected dustfall is non-magnetic fine particles, and the non-magnetic fine particles are mainly blast furnace slag-based dustfall.

  From this result, if the magnetic well sorting microwell and the magnetic sorting method according to the present invention are used, the dust falling from the steel manufacturing plant collected as a sample in the present example is the iron dust falling dust (iron ore, sintered ore, etc.) I found out that the majority was. In addition, it was found that the falling dust of iron-based dustfall and blast furnace slag-related dustfall (blast furnace granulated slag, blast furnace slow-cooled slag, etc.) can be efficiently separated by the magnetic separation device and the magnetic separation method according to the present invention. .

10 Magnetized Particle Substrate 11 Magnet 13 Spacer 100 Magnetic Well Sorting Microwell 105 Depression (Well)
110 Substrate for non-magnetized particles 120 Support plate 130 Gasket 140 Press plate 150 Fastening band Pm Magnetized fine particles Pn Non-magnetized fine particles L Volatile liquid

Claims (11)

A volatile liquid containing a group of fine particles composed of magnetized fine particles that are magnetized by applying a magnetic force and non-magnetized fine particles that are not magnetized is retained in the well of the microwell provided with a flat bottom surface. And a magnetic force sorting method for sorting the fine particle group into the magnetized fine particles and the non-magnetized fine particles,
A flat spacer made of a non-magnetic material attached to the tip of the magnet is immersed in the volatile liquid, and the fine particle group is sandwiched between the spacer and the bottom surface of the recess. The spacer particles are immersed in the volatile liquid and the magnetized fine particles are removed from the spacer under the condition that the magnet is not immersed in the volatile liquid. A magnetizing step for adsorbing to the magnet via
A magnetic force separation step of separating the magnet from the microwell and separating the magnetized fine particles adsorbed on the magnet via the spacer and the non-magnetized fine particles remaining in the recess;
Magnetic field sorting method characterized by including. The magnetizing step includes
A first step of spraying the particle group on the bottom of the depression;
A second step of injecting the volatile liquid into the depression so that the volatile liquid is at the predetermined depth within the depression;
A third step of immersing the spacer in the volatile liquid in the recess to bring the magnet closer to the fine particle group, and adsorbing the magnetized fine particles to the magnet via the spacer;
Including
The magnetic separation step includes
A fourth step of separating the magnet from the bottom surface of the recess and placing the magnetized fine particles attached to the spacer on a substrate for magnetized fine particles outside the microwell;
A fifth step of separating the magnet from the magnetized fine particle substrate and placing at least the magnetized fine particle on the magnetized fine particle substrate;
The magnetic field selection method according to claim 1, comprising: As the microwell, an assembly-type magnetic force sorting microwell composed of a plurality of members including a substrate for non-magnetic fine particles constituting the bottom surface of the depression,
After the fifth step,
A sixth step of disassembling the magnetic force selection microwell and taking out the substrate for the non-magnetizing fine particles;
A seventh step of removing the volatile liquid by leaving or heating the non-magnetic fine particle substrate;
The magnetic field selection method according to claim 2, further comprising:   In the fifth step, the magnet is detached from the spacer on the substrate for magnetized fine particles, and the magnetized fine particles attached to the spacer are placed on the substrate for non-magnetized fine particles together with the spacer. The magnetic force selection method according to claim 2 or 3, wherein   The average magnetic flux density on the surface on the fine particle group side of the spacer in the third step is 0.1T or more and 0.4T or less, according to any one of claims 2 to 4. Magnetic sorting method.   The magnetic particle sorting method according to any one of claims 1 to 5, wherein the fine particle group is made of dust falling from a steelmaking plant by a blast furnace method.   The magnetic separation method according to claim 1, wherein the volatile liquid is at least one alcohol selected from the group consisting of methanol, ethanol, and propanol. A microwell for magnetic force sorting used in the magnetic force sorting method according to any one of claims 3 to 7,
A flat, non-magnetic substrate for non-magnetic particles formed of a transparent and non-magnetic material;
A flat support plate that supports the substrate for non-magnetic particles and is formed of a non-magnetic material;
A gasket that does not dissolve in the volatile liquid and is formed of an elastic body having a hardness measured by a durometer of A30 or more and A65 or less and having one or more through holes;
A flat pressing plate formed of a non-magnetic material and having one or more through holes;
With
With the support plate, the substrate for the non-magnetized fine particles, the gasket, and the press plate stacked in order from below and fastened, the through hole of the gasket and the through hole of the press plate A magnetic well sorting microwell having a recess for holding the volatile liquid.   9. The magnetic well sorting microwell according to claim 8, wherein the elastic body is any one of butyl rubber, EPM, and EPDM.   The magnetic well sorting microwell according to claim 8 or 9, wherein the fastening method is band fastening. The magnetic well selecting microwell according to any one of claims 8 to 10, wherein the non-magnetic fine particle substrate is a glass plate.

Images