Method for recovering metal compound particles in metal material and method for analyzing metal compound particles in metal material

Abstract

To provide a simple method for recovering metal compound particles in a metal material while suppressing filtration leakage due to electrolytic extraction.SOLUTION: A method for recovering metal compound particles in a metal material according to the present invention includes an etching step of immersing the metal material in a solution and etching the metal material in the solution, a dispersion step of extracting metal compound particles to be recovered from the etched metal material and dispersing the metal compound particles in the solution, an aggregation step of adding an aggregation solvent for aggregating the metal compound particles into the solution in which the metal compound particles are dispersed and aggregating the dispersed metal compound particles, and a recovery step of filtering the solution containing the aggregated metal compound particles through a filter and recovering the metal compound particles on the filter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for recovering metal compound particles contained in a metal material and a method for analyzing metal compound particles contained in a metal material. [Background technology]

[0002] The size, quantity, and chemical composition of inclusions and precipitates (hereinafter referred to as "metal compound particles") contained in metal materials such as steel have a significant impact on the properties of the metal material. For example, in the case of steel, relatively large metal compound particles with particle sizes on the order of tens of micrometers are often treated as harmful particles that degrade the properties of the steel material. However, in recent years, technologies have been developed that actively utilize metal compound particles on the order of micrometers or smaller in size to control the structure of steel and thereby improve various properties of steel materials. Accordingly, there is an increasing need for appropriate quantitative analysis and particle size distribution measurement of tiny metal compound particles in steel materials.

[0003] To meet these needs, it is necessary to prepare a solution in which metal compound fine particles are stably dispersed in a solvent. Therefore, attempts have been made to prepare a dispersion in which metal compound fine particles are dispersed by performing a step of extracting and separating the metal compound fine particles from a metal material and a step of dispersing the extracted and separated metal compound fine particles in a liquid.

[0004] Electrowinning using a non-aqueous electrolyte is a well-known method for extracting and separating metal compound particles from metals. Electrowinning involves immersing a metal material as the anode and a platinum electrode as the cathode in a non-aqueous electrolyte, then performing electrolysis to dissolve the metal matrix of the metal material and extract the metal compound particles contained in the metal material. Electrowinning of steel materials using a non-aqueous electrolyte has the advantage of being able to selectively extract metal compound particles by selecting a solvent and potential appropriate for the substance to be extracted.

[0005] Non-Patent Document 1 discloses a non-aqueous electrolytic solution containing 10% acetylacetone (AA) or 4% methyl salicylate-1% salicylic acid (MS) as an iron chelating agent, and 1% tetramethylammonium chloride (TMAC) as a supporting electrolyte, as an electrolytic solution used in an electrowinning method for steel materials.

[0006] In electrolytic extraction, after electrolysis, most of the metal compound particles contained in the metal material remain attached to the surface of the metal material. Therefore, the metal compound particles are detached and dispersed from the surface of the metal material by ultrasonic irradiation or other methods in the solution, and then filtered to collect the particles on a filter. However, when attempting to recover the entire amount of precipitates in the electrolyte, if the precipitates are several nanometers in size, they are smaller than the filter pore size, and there is a possibility that they will be missed during filtration recovery. If missed particles occur, the analytical value will be low, making accurate quantitative analysis difficult. In response to this, Patent Document 1 discloses a method in which the precipitates and / or inclusions are extracted by vaporizing and evaporating the dispersion solution from which the precipitates and / or inclusions have been recovered. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2020-134192 [Non-patent literature]

[0008] [Non-Patent Document 1] "Sample Analysis Course: Steel Analysis", edited by the Japan Society for Analytical Chemistry, Maruzen Publishing Co., Ltd., published September 15, 2011, pp. 91, 101 Summary of the Invention [Problem to be solved by the invention]

[0009] The method of Patent Document 1 has a problem in that it takes a long time for the dispersion solution to evaporate. Furthermore, as ions dissolved in the dispersion solution evaporate, they precipitate on the collection tray, and some of them remain, which may result in a high analytical value. An object of the present invention is to provide a method for recovering metal compound particles from a metal material, which is capable of performing accurate quantitative analysis by suppressing filtration leakage in a simple manner. [Means for solving the problem]

[0010] The present invention has been made to solve the above-mentioned problems, and the method for recovering metal compound particles of the present invention suppresses leakage through filtration by aggregating metal compound particles obtained by etching a metal material using an appropriate aggregating solvent. The present invention includes the following aspects.

[0011] [1] A method for recovering metal compound particles contained in a metal material, comprising: an etching step of immersing a metal material in a solution and etching the metal material in the solution; a dispersion step of extracting metal compound particles to be recovered from the etched metal material and dispersing the metal compound particles in a solution; an aggregating step of adding an aggregating solvent for aggregating the metal compound particles to the solution in which the metal compound particles are dispersed, thereby aggregating the dispersed metal compound particles; a recovery step of filtering the solution containing the aggregated metal compound particles through a filter and recovering the metal compound particles on the filter; A method for recovering metal compound particles from a metal material, comprising:

[0012] [2] The method for recovering metal compound particles from a metal material according to [1], wherein the dispersion step is carried out while the metal material is immersed in the solution used in the etching step.

[0013] [3] The method for recovering metal compound particles in a metal material according to [1], characterized in that a solution for dispersing the metal compound particles to be recovered in the dispersion step is different from the solution used in the etching step.

[0014] [4] The method for recovering metal compound particles from a metal material according to [3], wherein in the recovery step, the solution used in the etching step is also filtered through the filter.

[0015] [5] The method for recovering metal compound particles in a metal material according to [4], characterized in that the coagulation solvent is added to the solution used in the etching step before filtering the solution used in the etching step through the filter.

[0016] [6] The Hansen solubility parameter distance R between the solution to which the coagulation solvent is added in the coagulation step and the metal compound particles to be recovered is calculated by the following formula (1): a 10.0 (J / cm ) for all the metal compound particles to be recovered 3 ) 1 / 2 The method for recovering metal compound particles contained in a metal material according to any one of the above [1] to [5], characterized in that: R a =[4(δ d1 -δ d2 ) 2 +(δ p1 -δ p2 ) 2 +(δ h1 -δ h2 ) 2 ] 1 / 2 … (1) where δ d1 is the London dispersion force of the metal compound particles to be recovered, δ p1 is the dipole-dipole force of the metal compound particles to be recovered, δ h1 is the hydrogen bonding strength of the metal compound particles to be recovered, δ d2 is the London dispersion force of the solution to which the coagulating solvent has been added, δ p2 is the dipole-dipole force of the solution to which the coagulating solvent has been added, δ h2 is the hydrogen bonding strength of the solution to which the coagulating solvent has been added.

[0017] [7] The method for recovering metal compound particles in a metal material according to any one of [1] to [6], characterized in that the etching of the metal material in the etching step is carried out by immersing an electrode containing the metal material and a counter electrode in an electrolytic solution to perform electrolysis.

[0018] [8] The method for recovering metal compound particles from a metal material according to [7], wherein the electrolytic solution contains a complexing agent that forms a complex with the metal material.

[0019] [9] The method for recovering metal compound particles in a metal material according to any one of [1] to [8], characterized in that in the dispersion step, ultrasonic waves are applied to a solution in which the metal compound particles to be recovered are dispersed, thereby detaching the metal compound particles from the surface of the metal material and dispersing the metal compound particles in the solution.

[0020]

[10] The method for recovering metal compound particles contained in a metal material according to any one of [1] to [9] above, wherein the metal material is a steel material.

[0021]

[11] The method for recovering metal compound particles in a metal material according to

[10] , characterized in that the metal compound particles to be recovered include one or more of Al compounds, Mn compounds, Ti compounds, and Mg compounds.

[0022]

[12] A method for analyzing metal compound particles in a metal material, comprising an analysis step of analyzing the metal compound particles to be recovered by any one of the methods for recovering metal compound particles in a metal material according to [1] to

[11] . [Effects of the Invention]

[0023] According to the present invention, a method for recovering metal compound particles from a metal material can be provided that solves the problem of low analytical values ​​due to leakage of fine particles through filtration, by simply performing the simple operation of etching the metal material and then adding, after electrolysis, a solvent that aggregates the metal compound particles to be recovered. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 shows Hansen sphere 3D plots of AlN and TiN particles. [Figure 2] FIG. 1 is a diagram showing quantitative values ​​of AlN, MnS, and TiN in steel sheets according to examples, determined by extraction residue analysis. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in detail below.

[0026] The present invention provides a method for recovering metal compound particles contained in a metal material, comprising the steps of: an etching step of immersing a metal material in a solution and etching the metal material in the solution; a dispersion step of extracting metal compound particles to be recovered from the etched metal material and dispersing the metal compound particles in a solution; an aggregating step of adding an aggregating solvent for aggregating the metal compound particles to the solution in which the metal compound particles are dispersed, thereby aggregating the dispersed metal compound particles; a recovery step of filtering the solution containing the aggregated metal compound particles through a filter and recovering the metal compound particles on the filter; Equipped with.

[0027] <Etching process> The etching step is a step of immersing a metal material containing metal compound particles in a solution and etching the metal material, with the aim of dissolving the matrix metal material and exposing the metal compound particles. The etching method is not limited.

[0028] For example, etching may be performed by immersing an electrode containing a metal material containing metal compound particles and a counter electrode in an electrolytic solution and dissolving the matrix metal material through electrolysis. The counter electrode may be, for example, a platinum electrode. The electrolytic solution may contain a complexing agent that forms a complex with the metal material. For example, when the matrix metal material is iron, known complexing agents such as acetylacetone, salicylic acid, maleic anhydride, citric acid, and phthalic acid may be used. The electrolytic solution may contain an electrolyte. Examples of the electrolyte include lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, tetramethylammonium chloride, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, tetramethylammonium hydroxide, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium tetrafluoroborate, and tetrabutylammonium hexafluorophosphate. The inclusion of these electrolytes can impart electrical conductivity to the electrolytic solution. The electrolysis conditions may be either constant potential conditions or constant current conditions. By adopting a predetermined potential and current during electrolysis, it is possible to selectively dissolve only the metal matrix without dissolving the target metal compound fine particles.

[0029] As an etching method, the metal matrix material may be dissolved by immersing it in an acid, or by immersing the metal matrix material in a solution in which a halogen is dissolved in methanol, and dissolving the metal matrix material by the oxidizing power of the halogen.

[0030] After the etching process, the metal matrix is ​​removed from the surface of the metal material, and as a result, metal compound fine particles are extracted and adhered to the surface.

[0031] <Dispersion process> In the dispersion step, after the etching step is completed, the metal compound particles to be recovered are extracted and dispersed in a solution. The metal compound particles may be dispersed while the metal material is immersed in the solution used in the etching step, or a solution different from the solution used in the etching step may be used as the solution in which the metal compound particles to be recovered are dispersed. Considering the possibility that the metal compound particles may fall off into the solution used in the etching step, it is preferable to disperse the metal compound particles while the metal material is immersed in the solution used in the etching step.

[0032] The method for dispersing metal compound particles in a solution is not limited. For example, the metal compound particles may be dispersed in a solution by vibrating a metal material having metal compound particles attached to its surface. Alternatively, ultrasonic waves may be applied to the solution in which the metal compound particles are to be dispersed, causing the metal compound particles to detach from the metal material and disperse in the solution. Applying ultrasonic waves is preferred because it promotes the dissociation of the metal compound fine particles from the metal material. The ultrasonic wave application time may be, for example, within 2 minutes or within 1 minute.

[0033] <Agglomeration process> In the aggregation step, a coagulation solvent is added to aggregate the metal compounds dispersed in the solution in the dispersion step. The coagulation solvent is not limited as long as it can aggregate the metal compounds to be recovered. The coagulation solvent to be added may be one type or two or more types.

[0034] In order to select an appropriate coalescing solvent, it is effective and preferable to use the Hansen solubility parameter. The Hansen solubility parameter will be explained below.

[0035] Hansen solubility parameter δ t is an index used to predict the solubility of a substance, and is a three-component decomposition of the solubility parameter (cohesive energy density) defined by Hildebrand, and can be expressed by the following formula (A).

[0036] δ t =(δ d 2+δ p 2 +δ h 2 ) 1 / 2 …(A)

[0037] In the above formula (A), δ d is the London dispersion force between molecules, δ p is the intermolecular dipole-dipole force, δ h is the intermolecular hydrogen bonding force.

[0038] Generally, the solubility parameter is defined by regarding the intermolecular force in a solution as a parameter of dissolving power, and the energy required to mix two components, ΔE M can be expressed as the difference between the cohesive energy when component 1 and component 2 exist as pure substances and the cohesive energy when they are a mixture of component 1 and component 2. In other words, if the solubility parameters of two substances are known, the greater the difference in these values, the greater the energy required for mixing, making them more likely to cohere.

[0039] The three parameters in formula (A) can be considered as coordinates in a three-dimensional space (Hansen space). When the Hansen solubility parameters of two substances are placed in the Hansen space, the greater the distance between the two points, the more likely they are to aggregate. The distance between the two points is the Hansen solubility parameter distance R shown in formula (B) below. a It can be expressed as:

[0040] R a =[4(δ d1 -δ d2 ) 2 +(δ p1 -δ p2 ) 2 +(δ h1 -δ h2 ) 2 ] 1 / 2 …(B)

[0041] δ in the above formula (B) d1 is the London dispersion force of component 1, δ p1 is the dipole-dipole force of component 1, δ h1is the hydrogen bonding strength of component 1, δ d2 is the London dispersion force of component 2, δ p2 is the dipole-dipole force of component 2, δ h2 is the hydrogen bonding strength of component 2. In the present invention, the Hansen solubility parameter distance between the metal compound particles to be recovered and the solution to which the coagulation solvent has been added is calculated, so δ d1 is the London dispersion force of the metal compound particles to be recovered, δ p1 is the dipole-dipole force of the metal compound particles to be recovered, δ h1 is the hydrogen bonding strength of the metal compound particles to be recovered, δ d2 is the London dispersion force of the solution to which the coagulating solvent has been added, δ p2 is the dipole-dipole force of the solution to which the coagulating solvent has been added, δ h2 is the hydrogen bonding strength of the solution to which the coagulating solvent has been added.

[0042] Hansen solubility parameter distance R a As mentioned above, the Hansen solubility parameter distance R is used to predict the solubility of substances, especially to evaluate the compatibility between organic materials. However, the inventors have investigated its use as a parameter to evaluate the coagulation of metal compound particles contained in metal materials. As a result, the Hansen solubility parameter distance R was found to be 0.01 for the solution to which the coagulation solvent was added and for all the metal compound particles to be recovered. a is 10.0 (J / cm 3 ) 1 / 2 It has been found that the case where the metal compound fine particles to be collected are preferably aggregated in the solvent when the aggregating solvent is added or more. Specifically, for example, when the metal compound fine particles to be collected are AlN, MnS, or TiN, the Hansen solubility parameter distance R between the solution to which the aggregating solvent is added and AlN is a , the Hansen solubility parameter distance R between the solution with the coagulating solvent added and MnS a , and the Hansen solubility parameter distance R between the solution with the coagulating solvent added and TiN a Each of these is 10.0 (J / cm 3 ) 1 / 2 It is preferable that this is the case.

[0043] Hansen solubility parameter distance R ais 11.0 (J / cm 3 ) 1 / 2 Above, 12.0(J / cm 3 ) 1 / 2 Above, 13.0(J / cm 3 ) 1 / 2 Above, 15.0(J / cm 3 ) 1 / 2 Above, 17.0(J / cm 3 ) 1 / 2 or more than 20.0 (J / cm 3 ) 1 / 2 The Hansen solubility parameter distance R a The larger the distance, the easier it is to aggregate, so there is no upper limit. a For example, 50.0 (J / cm 3 ) 1 / 2 Below, 40.0(J / cm 3 ) 1 / 2 Below, 30.0(J / cm 3 ) 1 / 2 or less than 25.0 (J / cm 3 ) 1 / 2 It may be the following:

[0044] In addition, if multiple metal compound particles are contained in the metal material, but some of the metal compound particles are not to be collected, the Hansen solubility parameter distance R a It's not a problem if it's small.

[0045] In the present invention, metal compound particles are aggregated by using an appropriate aggregating solvent. Therefore, even if the metal compound particles are precipitates of a few nanometers in size, the metal compound particles are aggregated before the recovery process described below, thereby preventing filtration leakage. This prevents low quantitative analysis values ​​in the subsequent analysis process, enabling accurate quantitative analysis. As a result, this technology is useful, for example, for designing steel products. The aggregating solvent is not particularly limited. For example, a suitable aggregating solvent can be selected based on the Hansen solubility parameters of solvents described in, for example, Charles M. Hansen, Hansen Solubility Parameters: A User's Handbook, Second Edition, CRC Press, 2007, and the Hansen solubility parameter of the mixed solvent, calculated as the weighted average of the solution in which the metal compound particles are dispersed and the aggregating solvent, is determined to be the desired Hansen solubility parameter distance R a The mixing ratio may be determined so that:

[0046] <Recovery process> In the recovery step, the solution containing the aggregated metal compound particles is filtered through a filter, and the metal compound particles are recovered on the filter. As described above, in the present invention, even metal compound particles with small particle sizes are aggregated before repair, so that even with a filter having a pore size of about 0.2 μm, for example, it is possible to recover the metal compound particles while suppressing filtration leakage.

[0047] In the above-mentioned dispersion step, when a solution different from the solution used in the etching step is used as the solution in which the metal compound particles to be recovered are dispersed, the solution used in the etching step may also be filtered through a filter. This makes it possible to recover metal compound particles that have remained in the solution used in the etching step due to, for example, falling off during the etching step. In this case, it is preferable to add the coagulation solvent used in the above-mentioned coagulation step to the solution used in the etching step to coagulate the metal compound to be recovered.

[0048] The method for recovering metal compound particles from a metal material of the present invention can be applied to any metal as long as it can etch the metal material that is the matrix of the metal material containing the metal compound particles. For example, the method is suitable for recovering metal compound particles from a steel material that contains Al compounds, Mn compounds, Ti compounds, Mg compounds, etc. as precipitates or inclusions.

[0049] <Analysis process> The method for recovering metal compound particles in a metal material, which comprises the above-mentioned etching step, dispersion step, aggregation step, and recovery step, can be used as a method for recovering metal compound particles in a method for analyzing metal compound particles in a metal material, which comprises an analysis step for analyzing the recovered metal compound particles.

[0050] In the analysis step, the metal compound particles recovered by the above-described method may be analyzed by a known method, such as ICP-AES (inductively coupled plasma atomic emission spectroscopy) or ICP-MS (inductively coupled plasma mass spectroscopy).

[0051] According to the present invention, it is possible to recover and analyze all of the fine metal compound particles that could not be recovered on a filter by suction filtration in the conventional recovery method, thereby greatly improving quantitative analysis. [Example]

[0052] Next, examples of the present invention will be described. The conditions in the examples are examples of conditions adopted to confirm the feasibility and effects of the present invention. The present invention is not limited to these examples of conditions. Various conditions can be adopted in the present invention as long as they do not deviate from the gist of the present invention and achieve the object of the present invention.

[0053] Example 1 The Hansen solubility parameters were calculated for AlN particles, TiN particles, and MnS particles as examples of metal compound particles contained in metal materials.

[0054] For solvents with known Hansen solubility parameters shown in Table 1 (Charles M. Hansen, Hansen Solubility Parameters: A User's Handbook, Second Edition, CRC Press, 2007), AlN particles (Sigma-Aldrich, primary particle size: 100 nm or less) and TiN particles (Fujifilm Wako Pure Chemical Industries, primary particle size: 1.2-1.8 μm) were added and subjected to ultrasonic treatment, after which the dispersibility of each particle was evaluated. A dynamic light scattering (DLS) device (Malvern, Zetasizer NanoS) was used to evaluate the dispersibility. The solvents for which dispersibility was evaluated were plotted on a three-dimensional graph (δ d ,δ p ,δ h ) and a sphere with the smallest radius was created so that the solvent in which the particles disperse is on the inside and the solvent in which they do not disperse is on the outside, and the coordinates of the center of the sphere were calculated (Hansen sphere analysis method). These coordinates are the Hansen solubility parameters for the AlN particles, TiN particles, and MnS particles.

[0055] [Table 1]

[0056] Figure 1 shows the analysis results of AlN, TiN, and MnS particles evaluated using the Hansen sphere analysis method. In Figure 1, the circles represent dispersed solvents, and the squares represent aggregated solvents. A sphere was then created so that all of the circle points were contained within it and had the smallest radius. The interior of the sphere represents the solvent with good dispersibility, and the center points of the spheres obtained, AlN (14.63, 16.26, 16.83), TiN (19.31, 16.82, 20.47), and MnS (17.14, 12.92, 16.28), respectively, are the Hansen solubility parameters for AlN, TiN, and MnS particles.

[0057] <Example 2> The metal material used was a hot-rolled steel sheet (C: 0.1 mass%, Si: 0.15 mass%, Mn: 1.8 mass%, Al: 0.02 mass%, S: 0.013 mass%, Ti: 0.05 mass%), and the metal compound particles were collected and analyzed. Separate observations using a transmission electron microscope (TEM) confirmed that fine precipitates of AlN, MnS, and TiN were present in this sample.

[0058] (Comparative Example 1) The steel material cut from the hot-rolled steel sheet was used as the anode, a platinum electrode as the cathode, and a 10% acetylacetone (AA)-1% tetramethylammonium chloride (TMAC)-methanol (MeOH) solution as the electrolyte. Electrolysis was performed under constant current conditions of 500 mA and 3600 C (coulombs).

[0059] Next, ultrasonic waves were applied to the electrolyte to disperse the metal compound particles in the electrolyte. The dispersed electrolyte was then suction filtered and collected on a Nuclepore filter (pore size: 0.2 μm). The resulting extraction residue was then acid-decomposed using sulfuric acid and phosphoric acid white smoke treatment, and quantitative analysis of Al, Mn, and Ti was performed using ICP-AES.

[0060] (Comparative Example 2) The steel material cut from the hot-rolled steel sheet was used as the anode, a platinum electrode as the cathode, and a 10% acetylacetone (AA)-1% tetramethylammonium chloride (TMAC)-methanol (MeOH) solution as the electrolyte. Electrolysis was performed under constant current conditions of 500 mA and 3600 C (coulombs).

[0061] Next, the steel plate with the metal compound particles attached to its surface was transferred into a dispersion liquid (methanol), and ultrasonic waves were applied to the dispersion liquid to cause the metal compound particles attached to the steel plate surface to fall off into the methanol solution. The dispersion liquid was then suction filtered and collected on a Nuclepore filter (pore size: 0.2 μm). The resulting extraction residue was then acid-decomposed using a sulfuric acid / phosphoric acid white smoke treatment, and quantitative analysis of Al, Mn, and Ti was performed using ICP-AES.

[0062] (Examples 1 to 3) The steel material cut from the hot-rolled steel sheet was used as the anode, a platinum electrode as the cathode, and a 10% acetylacetone (AA)-1% tetramethylammonium chloride (TMAC)-methanol (MeOH) solution was used as the electrolyte, and electrolytic extraction was carried out. The electrolysis conditions were constant current, 500 mA, and the current flow rate was 3600 C (coulombs). The Hansen solubility parameter distance R between the above electrolyte and the AlN particles was a is 6.8 (J / cm 3 ) 1 / 2 is.

[0063] Next, ultrasonic waves were applied in the electrolyte to disperse the metal compound particles in the electrolyte. Next, chlorobenzene (Hansen solubility parameter: (δ d ,δ p ,δ h ) = (19.0, 4.3, 2.0)) were added in the proportions shown in Table 2. The Hansen solubility parameter of the mixed solvent at this time was calculated as the weighted average of the Hansen solubility parameter of the electrolyte solution and the Hansen solubility parameter of chlorobenzene. After leaving it to stand overnight, the electrolyte was suction filtered and collected on a Nuclepore filter (pore size: 0.2 μm). The resulting extraction residue was then acid-decomposed using a sulfuric acid / phosphoric acid white smoke treatment, and quantitative analysis of Al, Mn, and Ti was performed using ICP-AES.

[0064] (Example 4) The steel material cut from the hot-rolled steel sheet was used as the anode, a platinum electrode as the cathode, and a 10% acetylacetone (AA)-1% tetramethylammonium chloride (TMAC)-methanol (MeOH) solution as the electrolyte. Electrolysis was performed under constant current conditions of 500 mA and 3600 C (coulombs).

[0065] Next, the steel sheet with the metal compound particles attached to its surface was transferred into a dispersion (methanol), and ultrasonic waves were applied to the dispersion to cause the metal compound particles attached to the steel sheet surface to fall off into the methanol solution. Chlorobenzene was then added in the same proportions as in Example 1, and the mixture was left standing overnight. The dispersion was then suction filtered and collected on a Nuclepore filter (pore size: 0.2 μm). The resulting extraction residue was then acid-decomposed using a sulfuric acid / phosphoric acid white smoke treatment, and quantitative analysis of Al, Mn, and Ti was performed using ICP-AES.

[0066] The ratio of methanol to chlorobenzene in each of the above examples, and the Hansen solubility parameter distance R between the solution and each of AlN, MnS, and TiN particles a The results are shown in Table 2 and Figure 2.

[0067] [Table 2]

[0068] In the conventional method (Comparative Examples 1 and 2) that does not undergo an aggregation step, the quantitative values ​​obtained by the extraction residue analysis are low. This is thought to be because no aggregation was performed for any of the AlN, MnS, or TiN particles, resulting in the leakage of fine particles through filtration. In contrast, in Invention Examples 1 to 4, the analytical values ​​were all high, confirming that leakage through filtration was suppressed.

[0069] From the results in Table 2 and Figure 2, R a As the value of R increases, the analytical value increases. a is 10.0 (J / cm 3 ) 1 / 2 From this result, it can be seen that R a is 10.0 (J / cm 3 ) 1 / 2 It is suggested that by using a solution with the above composition, particles are completely aggregated.

[0070] In addition, Example 1 of the present invention is an example of a solvent in which AlN and TiN particles are to be recovered, but MnS is not to be recovered. In Example 1 of the present invention, the R of the electrolyte solution containing the coagulating solvent for MnS is a is 5.1 (J / cm 3 ) 1 / 2 and is smaller than those of Comparative Examples 1 and 2. As a result, it is thought that MnS was well dispersed in the electrolyte with added coagulating solvent, and that there was more filtration leakage than in Comparative Examples 1 and 2, resulting in the lower analytical value of MnS. However, as mentioned above, since MnS is not the object of recovery in Inventive Example 1, the quantitative value of MnS in Inventive Example 1 is a reference value and is not a problem. On the other hand, the R of the electrolyte with added coagulating solvent for AlN and TiN in Inventive Example 1 a is 10.0 (J / cm 3 ) 1 / 2 As mentioned above, it is believed that the low analytical values ​​due to filtration leakage caused by particle aggregation did not occur.

[0071] Furthermore, in Inventive Example 4, although particle aggregation in the dispersion was sufficiently achieved, particle dropout in the electrolyte could not be avoided, and some particles dropped out into the electrolyte, which is thought to have resulted in an overall lower value compared to Inventive Examples 2 and 3. For confirmation, an aggregation solvent was added to the electrolyte used in Inventive Example 4, and the results were similarly recovered and added together for analysis. It was confirmed that the results were equivalent to those of Inventive Examples 2 and 3.

[0072] From the above results, it can be expected that the method of the present invention for recovering metal compound particles contained in metal materials will significantly improve the quantitative evaluation of metal compound particles contained in metal materials.

Claims

1. A method for recovering metal compound particles contained in a metal material, comprising: an etching step of immersing a metal material in a solution and etching the metal material in the solution; a dispersion step of extracting metal compound particles to be recovered from the etched metal material and dispersing the metal compound particles in a solution; an aggregating step of adding an aggregating solvent for aggregating the metal compound particles to the solution in which the metal compound particles are dispersed, thereby aggregating the dispersed metal compound particles; a recovery step of filtering the solution containing the aggregated metal compound particles through a filter and recovering the metal compound particles on the filter; A method for recovering metal compound particles from a metal material, comprising:

2. 2. The method for recovering metal compound particles contained in a metallic material according to claim 1, wherein the dispersion step is carried out while the metallic material is immersed in the solution used in the etching step.

3. 2. The method for recovering metal compound particles in a metal material according to claim 1, wherein a solution for dispersing the metal compound particles to be recovered in the dispersion step is different from the solution used in the etching step.

4. 4. The method for recovering metal compound particles contained in a metal material according to claim 3, wherein in the recovery step, the solution used in the etching step is also filtered through the filter.

5. 5. The method for recovering metal compound particles from a metal material according to claim 4, wherein the coagulating solvent is added to the solution used in the etching process before the solution used in the etching process is filtered through the filter.

6. The Hansen solubility parameter distance R between the solution to which the aggregation solvent is added in the aggregation step and the metal compound particles to be recovered is calculated by the following formula (1): a 10.0 (J / cm ) for all the metal compound particles to be recovered 3 ) 1 / 2 6. The method for recovering metal compound particles contained in a metal material according to claim 1, wherein the method is characterized by the above. R a =[4(d) d1 -d d2 ) 2 +(d) p1 -d p2 ) 2 +(d) h1 -d h2 ) 2 ] 1 / 2 … (1) where δ d1 is the London dispersion force of the metal compound particles to be recovered, δ p1 is the dipole-dipole force of the metal compound particles to be recovered, δ h1 is the hydrogen bonding strength of the metal compound particles to be recovered, δ d2 is the London dispersion force of the solution to which the coagulating solvent has been added, δ p2 is the dipole-dipole force of the solution to which the coagulating solvent has been added, δ h2 is the hydrogen bonding strength of the solution to which the coagulating solvent has been added.

7. The method for recovering metal compound particles from a metal material according to any one of claims 1 to 5, characterized in that the etching of the metal material in the etching step is carried out by a method of electrolysis in which an electrode containing the metal material and a counter electrode are immersed in an electrolytic solution.

8. 8. The method for recovering metal compound particles contained in a metallic material according to claim 7, wherein the electrolytic solution contains a complexing agent that forms a complex with the metallic material.

9. The method for recovering metal compound particles in a metallic material according to any one of claims 1 to 5, characterized in that in the dispersion step, ultrasonic waves are applied to a solution in which the metal compound particles to be recovered are dispersed, thereby detaching the metal compound particles from the surface of the metallic material and dispersing the metal compound particles in the solution.

10. 6. The method for recovering metal compound particles contained in a metallic material according to claim 1, wherein the metallic material is a steel material.

11. 11. The method for recovering metal compound particles in a metal material according to claim 10, wherein the metal compound particles to be recovered include one or more of Al compounds, Mn compounds, Ti compounds, and Mg compounds.

12. A method for analyzing metal compound particles in a metal material, comprising an analysis step of analyzing the metal compound particles to be recovered by the method for recovering metal compound particles in a metal material according to any one of claims 1 to 5.

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