JP6967331B2 - Method for measuring the amount of heavy metals eluted - Google Patents

Description

The present invention relates to a method for measuring the amount of elution of heavy metals. More specifically, the present invention relates to techniques suitable for use, for example, in measuring the amount of heavy metals eluted from clinker ash.

As the dissolution test method in Japan, Environmental Standards No. 46 (Soil Environmental Standards, 1991; Non-Patent Document 1) or Environmental Agency Notification No. 13 (Testing method for metals contained in industrial waste, Showa 48) Year; The operation according to Non-Patent Document 2) is common, and the elution amount value by these elution operations is widely recognized as an index of the elution amount of soil and industrial waste.

Environmental Agency Notification No. 46 "Soil Environmental Standards", Environmental Agency (at that time), 1991 Environmental Agency Notification No. 13 "Testing method for metals contained in industrial waste", Environmental Agency (at that time), 1973

However, the dissolution test method specified in Notification No. 46 and No. 13 of the Environment Agency requires a shaking operation for as long as 6 hours, and also requires a high degree of skill in measuring the prepared test solution. Therefore, there is a problem that it is necessary to measure a large number of samples in a short time, and it is not particularly suitable for use in a sample sorting process. Therefore, a measurement and evaluation technique that can obtain an elution amount value equivalent to that of the elution test method specified in the above notification by the Environment Agency in a shorter time is desired.

Therefore, the present invention provides a method for measuring the amount of heavy metals eluted, which incorporates an elution operation method capable of rapidly eluting heavy metals from a sample to be analyzed and a solution analysis method capable of easily analyzing the eluate concentration. The purpose is to provide.

In order to achieve such an object, the method for measuring the amount of heavy metal elution of the present invention is to put a sample to be analyzed having a particle size of 5 mm or less into a cylindrical container at the bottom of a hemispherical bottom with a closed bottom, and for water or elution. Along with adding the solution, a crushing medium having a particle size of 0.1 to 10 mm is added, and the cylindrical container is vibrated by the eccentric rotation given by the eccentric vibration device to vibrate and stir the contents in the cylindrical container. However, the eluate from which the heavy metals contained in the sample to be analyzed have been eluted is obtained.

Therefore, according to this method for measuring the amount of heavy metals eluted, the operation of elution of heavy metals contained in the sample to be analyzed is rapidly performed. In addition, the crushing effect of small energy is applied to the wide particle size range of the sample to be analyzed in the cylindrical container, and mild crushing is performed.

The substances subject to elution and analysis in the present invention are substances that fall under the Type 2 Specified Hazardous Substances under the Soil Contamination Countermeasures Act (Act No. 53 of 2004), and these substances are referred to in the description of the present invention. Notated as "heavy metals". Specifically, the "heavy metals" in the present invention include cadmium (Cd), hexavalent chromium (Cr (VI)), cyanide ((CN) ₂ ), mercury (Hg), selenium (Se), and lead ( It shall contain at least Pb), arsenic (As), fluorine (F), and boron (B).

In the method for measuring the elution amount of heavy metals of the present invention, the sample to be analyzed may be at least one of coal ash, incinerated ash, slag, and cement solidified of coal ash and incinerated ash. In this case, the elution operation of heavy metals contained in coal ash, incineration ash, slag, coal ash and cement solidification of incineration ash is appropriately performed.

In the method for measuring the elution amount of heavy metals of the present invention, the particle size of the pulverizing medium may be in the range of 0.5 to 3 mm. In this case, the contents in the cylindrical container are well agitated and the sample to be analyzed is appropriately crushed.

In the method for measuring the elution amount of heavy metals of the present invention, the specific gravity of the pulverizing media may be in the range of ^{1.0 to 4.3 g / cm 3.} In this case, the contents in the cylindrical container are well agitated and the sample to be analyzed is appropriately crushed.

In the method for measuring the amount of heavy metal elution of the present invention, the inner diameter of the cylindrical container is in the range of 15 to 40 mm, the sample to be analyzed is in the range of 2 to 20 g, and the water or elution solution is 20 to 200. The solid-liquid ratio may be in the range of mL and may be 10 L / kg. In this case, the contents in the cylindrical container are well agitated and the sample to be analyzed is appropriately crushed.

In the method for measuring the amount of heavy metal elution of the present invention, the orbit diameter for eccentric rotation is in the range of 3 to 5 mm, the rotation speed of eccentric rotation is in the range of 1000 to 3000 rpm, and the time is 20 to 120. It may be in the range of minutes. In this case, the contents in the cylindrical container are well agitated and the sample to be analyzed is appropriately crushed.

In the method for measuring the amount of heavy metals eluted in the present invention, a reducing agent is added to the eluate, a chelating agent is added, and the heavy metals are filtered through a filter to collect the heavy metals. After drying, the arsenic content may be quantified by a fluorescent X-ray element analysis method. In this case, in addition to the operation of elution of heavy metals contained in the sample to be analyzed, the amount of arsenic elution in the eluate from which the heavy metals are eluted is rapidly measured.

In the method for measuring the elution amount of heavy metals of the present invention, L-cysteine may be used as a reducing agent. In this case, the reduction of arsenic (V) to arsenic (III) is well performed.

In the method for measuring the elution amount of heavy metals of the present invention, a 1% DBDTC solution may be used as the chelating agent. In this case, arsenic (III) chelation is well performed.

In the method for measuring the amount of heavy metals eluted in the present invention, the pH of the eluate may be adjusted using the discoloration of methyl orange as an index. In this case, the pH of the eluate is easily adjusted.

According to the method for measuring the elution amount of heavy metals of the present invention, the crushing effect of a small amount of energy is applied to a wide particle size range of the sample to be analyzed in the cylindrical container, and mild crushing is performed. heavy metals mild with results close to the crushing effect, elution operations heavy metals contained in the analysis sample by dissolution test methods are defined in the Patent are included in the quick line cracks, analysis sample It becomes possible to perform the kind of analysis efficiently in a short time.

The method for measuring the amount of heavy metal elution of the present invention has a specific range such as a cylindrical container, a sample to be analyzed, a media for crushing, water, and specifications and set values related to eccentric rotation for stirring and crushing. In this case, the contents in the cylindrical container can be well agitated and the sample to be analyzed can be appropriately crushed. Therefore, bias / variation and error from the true value are eliminated and the accuracy is high. It becomes possible to provide the measurement result. Moreover, the dissolution operation equivalent to that of the Environment Agency official method is performed in a shorter time than the dissolution test method (referred to as "Environment Agency official method") specified in Notification No. 46 of the Environment Agency (in other words,). It is possible to reproduce the elution of heavy metals from the sample to be analyzed by the dissolution test), and by estimating the result by the official method of the Environment Agency, the analysis of heavy metals contained in the sample to be analyzed is efficient. It becomes possible to do it.

In the method for measuring the amount of heavy metals eluted in the present invention, in addition to the operation of elution of heavy metals contained in the sample to be analyzed, the amount of arsenic in the eluate from which the heavy metals are eluted can be quickly measured. Therefore, it becomes possible to efficiently quantify the arsenic contained in the sample to be analyzed in a short time. Moreover, it is possible to estimate the elution amount calculated by the JIS official method, although it is shorter and simpler than the analytical method defined in JIS K 0102 (referred to as "JIS official method"). By estimating the result by the JIS official method, it becomes possible to efficiently quantify the amount of arsenic contained in the sample to be analyzed.

The method for measuring the elution amount of heavy metals of the present invention can satisfactorily reduce arsenic (V) to arsenic (III) when L-cysteine is used as a reducing agent, and chelate. When a 1% DBDTC solution is used as an agent, arsenic (III) chelation can be performed well, so bias / variation and error from the true value are eliminated, and highly accurate measurement results are obtained. Will be able to provide.

In the method for measuring the amount of heavy metal eluate of the present invention, when the pH of the eluate is adjusted using the discoloration of methyl orange as an index, the pH of the eluate can be easily adjusted. It is possible to efficiently quantify the amount of arsenic by reducing the labor required for ray element analysis.

It is a bird's-eye view from the front which shows the schematic structure of an example of the eccentric vibration apparatus used in the method of measuring the elution amount of heavy metals of this invention. It is a figure which shows the change of the SN ratio with respect to the official method value of the elution amount value by the difference of the material and the diameter of the crushing medium in Example 1. FIG. It is a figure which shows the change of the sensitivity with respect to the official method value of the elution amount value by the difference in the material and diameter of the crushing medium in Example 1. FIG. It is a figure which shows the change of the particle size of coal ash after stirring by the difference in the shape of the bottom and the bottom of the cylindrical container in Example 1. FIG. It is a figure which shows the change of the relative value with respect to the official method value of the elution amount value by the difference of the stirring time in Example 1. FIG. It is a figure which shows the correlation between the official method value and the elution amount value in Example 1. FIG. It is a figure which shows the change of the fluorescent X-ray intensity by the difference of the solution analysis conditions in Example 2. FIG. (A) is a figure which shows the change of the fluorescent X-ray intensity by the difference in the reaction time of a chelating agent. (B) is a figure which shows the change of fluorescent X-ray intensity by the difference in pH of the eluate. It is a figure which shows the calibration curve of the relative intensity and the arsenic (III) concentration of the fluorescent X-ray of arsenic (III) and cobalt in Example 2. FIG. It is a figure which shows the change of the fluorescent X-ray intensity by the difference of the treatment time by the reducing agent in Example 2. FIG. It is a figure which shows the correlation between the concentration and the measured value of the standard sample of arsenic (III) and arsenic (V) in Example 2. FIG. It is a flowchart explaining the arsenic analysis procedure of the elution test liquid of clinker ash in Example 3. It is a figure which shows the correlation between the value by the JIS official method and the elution amount value in Example 3. FIG.

Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

FIG. 1 shows an example of an embodiment (specifically, an apparatus used for carrying out the measurement method) of the method for measuring the amount of elution of heavy metals according to the present invention.

The method for measuring the amount of heavy metals elution according to the present invention is broadly defined as the first step of performing an elution operation for elution of heavy metals from the sample to be analyzed, and the elution solution obtained by the elution operation as the substance to be analyzed. It consists of the second stage of measuring the concentration of heavy metals.

In the method for measuring the amount of heavy metals eluted in the present embodiment, a sample 1 to be analyzed having a particle size of 5 mm or less and water or an elution solution (2) are placed in a cylindrical container 9 having a closed bottom (9a). At the same time, a crushing medium 8 having a particle size of 0.1 to 10 mm is added, and the cylindrical container 9 is vibrated by eccentric rotation to vibrate and stir the contents in the cylindrical container 9 for analysis. An eluent containing the heavy metals contained in the target sample 1 is obtained, and after adding a reducing agent to the eluate, a chelating agent is added and then filtered with a filter to collect the heavy metals. Then, after the filter that collects the heavy metals is dried, the arsenic content is quantified by the fluorescent X-ray element analysis method.

Specific examples of the sample 1 to be analyzed in the present invention include coal ash, incinerated ash, slag, and cement solidified coal ash and incinerated ash.

Coal ash contains at least fly ash and clinker ash.

The incinerator ash includes at least general waste incinerator ash, sewage sludge incinerator ash, paper sludge incinerator ash, and steel dust (excluding those corresponding to the above-mentioned coal ash).

For slag, at least the molten solidified waste (that is, the general waste is directly produced under high temperature conditions, or the incineration residue of general waste is heated under high temperature conditions, and the inorganic substances are melted and then cooled. Solidified slag), sewage sludge molten slag, especially blast furnace slag and steelmaking slag related to iron making, non-ferrous slag (specifically, ferronickel slag, copper slag, zinc slag), electric furnace slag, and especially related to power generation. Includes coal gasification slag.

The sample 1 to be analyzed is adjusted in advance (in other words, before being charged into the cylindrical container 9) so that the particle size is 5 mm or less.

The heavy metals eluted in the eluate obtained by stirring with vibration (that is, the heavy metals originally contained in the sample 1 to be analyzed) include cadmium (Cd), hexavalent chromium (Cr (VI)), and cyanide. ((CN) ₂ ), mercury (Hg), selenium (Se), lead (Pb), arsenic (As), fluorine (F), boron (B) and the like can be mentioned.

(1) Elution operation method An elution operation method capable of rapidly elution of heavy metals from the sample 1 to be analyzed, which is used in the method for measuring the amount of heavy metals elution according to the present invention, will be described.

The cylindrical container 9 is based on a hollow cylindrical shape, and one end (specifically, the lower end at the time of use) of the cylindrical central axial direction Dax (in other words, the longitudinal direction of the cylinder) is closed and the other end. (Specifically, the upper end at the time of use) is open (in other words, it is open).

A removable lid 9b that can seal the open end of the cylindrical container 9 on the open side (that is, the upper end side at the time of use) at least to the extent that the contents do not leak is attached. ..

The size of the cylindrical container 9 is not limited to a specific dimension, but the inner diameter in the cross section orthogonal to the cylindrical central axis direction Dax (in other words, the longitudinal direction of the cylinder) is in the range of about 15 to 40 mm. It is preferable that the dimension is set to one of the dimensions and the length of the Dax (longitudinal direction of the cylinder) in the central axial direction of the cylinder is set to any dimension in the range of about 70 to 120 mm, and the inner diameter is particularly set. It is more preferable to set the dimension to any one of the range of about 20 to 35 mm.

Specifically, as the cylindrical container 9, for example, a centrifuge tube, a test tube, a conical tube, or the like can be used.

The closed end 9a (that is, the lower end side at the time of use) of the cylindrical container 9 may be a hemispherical shape that protrudes outward of the cylindrical container 9, in other words, a round bottom. preferable.

The cylindrical container 9 is installed in the eccentric vibration device 10 with the closed portion as the bottom and the cylindrical central axial direction Dax (in other words, the longitudinal direction of the cylinder) in the vertical direction (in other words, the vertical direction).

The amount of water (specifically, pure water, ultrapure water) or elution solution (denoted as "pure water, etc. 2") charged into the cylindrical container 9 is into the cylindrical container 9. The solid-liquid ratio with the input sample 1 to be analyzed is taken into consideration, and the amount is adjusted according to the amount of the sample 1 to be analyzed. The solid-liquid ratio between the sample 1 to be analyzed and the pure water or the like 2 is adjusted to be, for example, about 10 L / kg.

As the elution solution, for example, a solution containing hydrochloric acid, sulfuric acid, nitric acid, acetic acid, sodium acetate, calcium chloride, or calcium hydroxide may be used.

In this embodiment, the solid-liquid ratio is set to 10 L / kg in consideration of the same conditions as those specified in the Environmental Agency Notification Nos. 46 and 13. However, the solid-liquid ratio is not limited to 10 L / kg, and if the solid-liquid ratio of the dissolution test method, which is the official standard, is changed to a value other than 10 L / kg, ( By setting the same conditions as the changed solid-liquid ratio (within the range of about 1.5 to 25 L / kg), the present invention can obtain the same value as the elution amount value of the elution test method.

The amount of the sample 1 to be analyzed and the pure water, etc. 2 to be put into the cylindrical container 9 is not limited to a specific amount, but the sample 1 to be analyzed is in the range of about 2 to 20 g. The amount of pure water, etc. 2 may be any amount in the range of about 20 to 200 mL (after adjusting the solid-liquid ratio to, for example, 10 L / kg). It is more preferable that the sample 1 to be analyzed is 3.5 g and the amount of pure water 2 is 35 mL.

In order to shorten the time required for elution by simultaneously crushing and elution of the sample 1 to be analyzed in the cylindrical container 9, a small-diameter crushing medium 8 (also referred to as a “ball” for stirring) is used in the cylindrical container 9. It is added inward (in other words, charged) and stirred together with the sample 1 to be analyzed.

As the crushing medium 8 added / charged into the cylindrical container 9, a granular medium formed in the form of a sphere or a cylinder is used, and specifically, for example, beads are used.

The particle size of the crushing media 8 is not limited to a specific size, but is preferably set in the range of about 0.1 to 10 mm, preferably in the range of about 0.5 to 3.0 mm. It is more preferably set, more preferably set in the range of about 0.8 to 2.0 mm, and most preferably set in the range of about 1.0 to 1.2 mm. As the crushing media 8, a plurality of types of media having different particle sizes may be used.

Specific examples of the material of the crushing medium 8 include metal, ceramic, glass, and resin.

The milling media 8, it is preferable to use a specific gravity in the range of about 1.0~4.3 g / cm ^3, a range specific gravity of about 1.1 to 2.7 g / cm ³ It is more preferred that some are used. As the crushing media 8, a plurality of types of media having different specific densities may be used at the same time (in other words, they may be put into the cylindrical container 9 together).

Although the input amount of the crushing media 8 is not limited to a specific amount, the actual volume (that is, weight / specific gravity) of the crushing media 8 with respect to the liquid amount [mL] of pure water or the like 2 [cm ³ ]. Is preferably set to any amount in the range of 0.03 to 0.5 cm ³ / mL, and any of the amount in the range of ^{0.08 to 0.3 cm 3 / mL.} It is more preferable to set the amount to ^{about 0.12-0.25 cm 3} / mL, and even more preferably to set the amount to any one of the range of about ^{0.12 to 0.25 cm 3 / mL, about 0.146 cm 3} / mL. Most preferably, it is set to the amount of.

The eccentric vibration device 10 vibrates the cylindrical container 9 by eccentric rotation with the horizontal plane as an orbit, and the contents in the cylindrical container 9 (specifically, the sample to be analyzed 1, pure water, etc. 2, crushing media). 8) is agitated. The eccentric vibration device 10 is also referred to as an "eccentric vibration type mixer".

The orbit diameter of the eccentric vibration device 10 is preferably set to any value in the range of about 3.0 to 5.0 mm, and any of the values in the range of 3.6 to 4.1 mm. It is more preferable to set to the value.

The orbital diameter (that is, orbital diameter) is also called the shaking diameter (that is, the shaking diameter), and is the diameter of the circle in which the vibration table of the orbital shaker operates (for example, Wolf Klockner et al. " See "Advances in shopping technologies", Trends in Biotechnology June 2012, Vol.30, No.6, http://www.cell.com/trends/biotechnology/pdf/S0167-7799(12)00031-5.pdf ( _{D 0} in FIG. 1 (a) is the orbit diameter / shaking diameter)).

The rotation speed of the eccentric vibration device 10 is preferably set in the range of about 1000 to 3000 rpm, more preferably set in the range of about 2000 to 3000 rpm, and most preferably set in the range of about 2500 rpm. preferable.

The time for vibrating and stirring the cylindrical container 9 by the eccentric vibration device 10 is preferably set to any time in the range of about 20 to 120 minutes, and is preferably set to any time in the range of about 45 to 100 minutes. It is more preferable to set the time of.

The temperature inside the container when the cylindrical container 9 is vibrated and agitated by the eccentric vibration device 10 is preferably room temperature, but may be set to any temperature within the range of 15 to 70 ° C.

The eluate in the cylindrical container 9 after vibration stirring is used, and cadmium (Cd), hexavalent chromium (Cr (VI)), cyanide ((CN) ₂ ), mercury (Hg), selenium (Se), Elutions are analyzed for at least one of lead (Pb), arsenic (As), fluorine (F), and boron (B).

According to the elution operation method corresponding to the first step of the method for measuring the amount of heavy metals elution configured as described above, the elution operation of heavy metals contained in the sample 1 to be analyzed can be rapidly performed. Therefore, it becomes possible to efficiently analyze the heavy metals contained in the sample 1 to be analyzed in a short time.

(2) Solution analysis method A solution analysis method that can easily analyze the eluate concentration used in the method for measuring the amount of heavy metal elution according to the present invention will be described.

In the solution analysis method according to the present invention, arsenic (specifically, arsenic (III) +) in the test solution (specifically, the eluate obtained by carrying out the above-mentioned elution operation method). Arsenic (V)) is the measurement target.

As an outline of the analysis procedure, arsenic in the eluent is insolubilized with dibenzyldithiocarbamic acid (denoted as "DBDTC"), and the collected material collected by a membrane filter is collected by an energy dispersive X-ray fluorescence analyzer ("XRF analysis"). It is detected and quantified by "device"). Since arsenic (V) is not insolubilized by DBDTC, it is reduced to arsenic (III) for analysis as a pretreatment.

A) Solution Preparation Use ultrapure water such as JIS K 0557 A4 grade as water.

A 0.5 mol / L sodium acetate solution (29.725 g / L acetic acid) and a 0.5 mol / L sodium acetate solution (sodium acetate 41.015 g / L) are mixed to adjust the pH to 4.0, and the pH is adjusted to 0. Prepare a .5 mol / L acetate buffer (pH 4.0).

Dissolve 1 g of sodium dibenzyldithiocarbamate in methanol to make 100 mL, and then filter with a filter unit (which does not completely dissolve) to prepare a 1% DBDTC solution.

Dilute 1 mL of cobalt (Co) standard solution (1000 mg / L) with water to 100 mL to prepare a 10 mg / L Co standard solution.

Dilute 1 mL of arsenic (As) standard solution (1000 mg / L) with water to 100 mL to prepare a 10 mg / L As standard solution.

Dilute 10 mL of 10 mg / L As standard solution with water to 100 mL to prepare 1 mg / L As standard solution.

Dilute 0.5 to 5 mL of 1 mg / L As standard solution with water to 100 mL to prepare 0.005 to 0.05 mg / L As standard solution. In addition, prepare a plurality of types of As standard solutions having different concentrations, which are required for preparing a calibration curve.

B) Calibration curve (As)
<Procedure 1> Add 2 mL of 0.5 mol / L acetate buffer (pH 4.0) to each of 30 mL of 0.005 to 0.05 mg / L As standard solution of multiple types.
<Procedure 2> Add 1 mL of 10 mg / L Co standard solution.
<Procedure 3> After raising the temperature to 30 ° C., add 1 mL of 1% DBDTC solution as a chelating agent, and stir for 30 seconds to 1 minute. Specifically, the temperature rise is performed by, for example, allowing it to stand in a constant temperature water tank at 30 ° C. for about 10 minutes or using a band heater or the like.
<Procedure 4> Let stand for about 20 minutes in a constant temperature bath at 30 ° C.
<Procedure 5> Suction filtration is performed with a membrane filter (specifically, for example, a pore size of 0.2 μm and a diameter of 25 mm).
<Procedure 6> Collect the residual liquid in the container containing the eluate using a small amount of water.
<Procedure 7> Wash the filter unit and membrane filter used for filtration with a small amount of water.
<Procedure 8> A membrane filter is placed on a prolen film attached to an XRF sample container that is set and used in an XRF analyzer. At this time, make one or two holes of about 1 mm in the bottom of the XRF sample container with a drill or the like, and make several holes in the prolen film with an injection needle or the like.
<Procedure 9> Air dry for 10 to 15 minutes.
<Procedure 10> A prolen film is attached to the upper surface of the XRF sample container, and analysis is performed by a fluorescent X-ray elemental analysis method. No holes can be made in the prolen film stretched on the upper surface of the XRF sample container. As a result, the membrane filter is fixed to the XRF sample container so as to be sandwiched between the two prolen films.

C) Quantification of the eluate obtained by the elution operation method <Procedure 1> Add 0.1 mL of 0.1% methyl orange solution to 30 mL of the eluate obtained by the above "(1) Elution operation method".
<Procedure 2> Add 1 mol / L hydrochloric acid until the color turns orange while stirring with a stirrer.
<Procedure 3> Add 2 mL of 0.5 mol / L acetate buffer (pH 4.0).
<Procedure 4> Let stand in a constant temperature water tank at 90 to 95 ° C for about 10 minutes.
<Procedure 5> Add 0.2 g of L-cysteine hydrochloride monohydrate as a reducing agent while stirring with a stirrer. Here, when L-cysteine hydrochloride monohydrate is added, the pH of the solution drops to about 2, but according to the findings of the inventors, there is almost no effect on the analysis results, so the pH is readjusted. Does not have to be done. In addition, according to the findings of the inventors, there is no difference in the analysis results even if 0.2 g of L-cysteine is added instead of L-cysteine hydrochloride monohydrate.
<Procedure 6> Let stand in a constant temperature water tank at 90 to 95 ° C for about 15 minutes.
<Procedure 7> Cool to room temperature in ice water.
<Procedure 8> The same operation as <Procedure 2> to <Procedure 10> of the above "B) Calibration curve (As)" is performed.

D) Conditions for X-ray fluorescence elemental analysis (referred to as "XRF analysis") XRF analysis is performed, for example, under the following conditions.
i) XRF analyzer: Bruker AXS S2 RANGER LE
ii) Tube: Pd
iii) Tube voltage, tube current: 50 kV, 1000 μA
iv) Primary X-ray filter (film thickness): Cu (100 μm)
v) Measurement atmosphere: Atmosphere
vi) Measurement time: 20 minutes
vii) Measurement peak: As Kα, Co Kα (internal standard)

E) arsenic concentration calculated calibration curve, the calibration curve is created relative intensities of the As K [alpha and _{Co Kα (I As / I Co} ) is used for the As concentration W _As of As standard solution (specifically, the following equation 1) of the arsenic concentration in the eluate is calculated (i.e., calculates the X _as with replacing W _as in equation 1 to X _as).

(Number 1) I _As / I _Co = a · _Was + b
Here, I _As / I _Co : Relative intensity of fluorescent X-rays between As Kα and Co Kα,
_Was : As concentration of As standard solution,
X _As : As concentration of eluate,
a: Coefficient,
b: Represents a constant.

It should be noted that the necessity of energy correction and drift correction is confirmed when using the XRF analyzer, and if the state of the XRF analyzer does not change significantly, it is not necessary to create a calibration curve for each analysis or calculate the overlap correction coefficient.

According to the solution analysis method corresponding to the second step of the method for measuring the amount of heavy metal elution configured as described above, arsenic elution of the eluate in which the heavy metal contained in the sample 1 to be analyzed is eluted. Since the amount can be measured quickly, the arsenic contained in the sample 1 to be analyzed can be efficiently quantified in a short time. According to the above solution analysis method, since analysis can be performed even with a small amount of eluate, it can be used in combination with the above-mentioned elution operation method corresponding to the first step of the method for measuring the amount of heavy metals elution. It is possible to shorten the required time as a whole for measuring the amount of heavy metals eluted. Moreover, since the solution analysis method has good sensitivity, it is possible to measure the amount of arsenic contained in the sample 1 to be analyzed in detail.

Here, according to the method for measuring the amount of heavy metal elution according to the present invention, the amount of elution obtained by the elution test specified in Notification No. 46 of the Environment Agency can be estimated (in other words, reproduced) with good accuracy. Therefore, as a method of utilizing the method for measuring the amount of heavy metal elution according to the present invention, specifically, for example, it is applied to the discrimination of a sample whose elution amount is surely smaller than the soil environment standard value for the cleanse ash at the time of shipment. To do.

Although the above-described embodiment is an example of a preferred embodiment of the present invention, the embodiment of the present invention is not limited to the above-mentioned embodiment, and the present invention is not limited to the above-mentioned embodiment and does not deviate from the gist of the present invention. The invention can be modified in various ways.

For example, in the above-described embodiment, the elution operation method for eluting heavy metals from the sample 1 to be analyzed and the solution analysis method for analyzing the concentration of the eluate obtained by the elution operation method are used in combination. The method for measuring the amount of heavy metal elution according to the present invention has an essential configuration of the elution operation method in the above-described embodiment, and the solution analysis method has an essential configuration for the method for measuring the amount of heavy metal elution according to the present invention. No. For example, after the elution operation method in the above-described embodiment is performed, the elution amount is analyzed by a method compliant with JIS K 0102 instead of the solution analysis method in the above-mentioned embodiment. May be.

The elution amount obtained by the elution test specified in Notification No. 46 of the Environment Agency is estimated (in other words, reproduced) for the elution operation method corresponding to the first step of the method for measuring the elution amount of heavy metals according to the present invention. An example in which the validity when used as a method is verified will be described with reference to FIGS. 2 to 6.

In this example, 28 types of clinker ash were used as test samples. All test samples were measured for the concentration of major components by fluorescent X-ray elemental analysis (referred to as "XRF analysis"), and the results shown in Table 1 were obtained.

In addition, the elution test specified in Notification No. 46 of the Environment Agency was conducted for all test samples, and the elution amounts of arsenic, selenium, hexavalent chromium, fluorine, and boron were analyzed. The elution amount analysis was performed according to JIS K 0102. The elution / analysis method based on Notification No. 46 of the Environment Agency and JIS K 0102 is called the "official method", and the concentration value of each component obtained by the official method is called the "official method value".

In this example, SI-A286 of Scientific Industries, Inc. of the United States was used as the eccentric vibration device 10 (see FIG. 1) for stirring the pulverizing media 8 together with the sample 1 to be analyzed. The device has a mechanism for agitating the contents in the container by applying eccentric vibration to the cylindrical container 9.

In order to apply eccentric vibration to the cylindrical container 9, a 50 mL centrifuge tube adapter SI-V203, which is one of the attachments of the above device, was used.

The rotation speed of the eccentric vibration device 10 was set to 2500 rpm in consideration of good stirring of the contents in the cylindrical container 9.

(1) Verification of the influence of the shape of the bottom / bottom surface of the cylindrical container 9 and the type of crushing media A) Test conditions In order to verify the influence of the shape of the bottom / bottom surface of the cylindrical container 9, the inside of the cylindrical container 9 Zirconia silica balls (AS ONE Co., Ltd., CZS balls) and glass beads (AS ONE Co., Ltd., material: soda glass) are used as the crushing media 8 to be added (in other words, charged), and the cylindrical container 9 is used. A container (48 mL centrifuge tube; Cartell, model number 306) having a hemispherical shape (in other words, a round bottom) and a conical container (50 mL conical tube) are used as the bottom and bottom 9a, respectively. The measurement was set in the combination of.

As the test sample, a sample whose particle size was adjusted to 2 mm or less after air-drying was used in the same manner as in the pretreatment step of the method specified in Notification No. 46 of the Environment Agency. The amount charged into the cylindrical container 9 was 3.5 g for the test sample and 35 mL for pure water and the like 2.

The water quality analysis was carried out in accordance with JIS K 0102 (unless otherwise noted, the same applies to the water quality analysis in Examples 2 and subsequent examples in addition to all the water quality analyzes in Example 1).

The input amount of the crushing media 8 was set so that the actual volume (that is, weight / specific gravity) of the crushing media 8 was 5.1 cm ³ (this is the liquid amount [mL] of pure water or the like 2]. Equivalent to about 0.146 cm ³ / mL in terms of the actual volume (ie, weight / specific density) [cm ³ ] of the crushing media 8; in addition to all measurements in Example 1 unless otherwise noted. The measurements in the examples after Example 2 were also carried out under the same conditions).

Further, in order to verify the influence of the types of the crushing media 8, three types of crushing media 8 are used: zirconia silica balls (same as above), zirconia balls (Nikkato Corporation, YTZ balls), and glass beads (same as above). Was done. Then, conditions of a plurality of diameters (specifically, 3 types for zirconia silica balls, 8 types for glass beads, and 3 types for zirconia balls) are set for each of the types of the crushing media 8, which are typical. The elution operation was performed on 6 samples (specifically, sample numbers 10, 11, 13, 15, 18, 21 in Table 1).

From the relationship between the elution amount value obtained by the above elution operation and the official method value, the prediction performance of the official method value for each of the cases set as described above was evaluated.

The SN ratio η of Taguchi's dynamic characteristics (Genichi Taguchi et al. "Basic Offline Quality Engineering", Japanese Standards Association, 2007) used in the field of quality engineering as an evaluation index of the prediction performance of official legal values (specifically, (Calculated by the following formula 2) and sensitivity S (specifically, calculated by the following formula 3) were used.

ここに、 η：ＳＮ比，
ｒ：有効序数，
Ｓ_β：入力の効果，
Ｖ_ｅ：誤差分散 をそれぞれ表す。

Here, η: SN ratio,
r: Effective ordinal number,
S _β : Input effect,
_Ve : Represents the error variance.

ここに、 Ｓ：感度，
Ｓ_β：入力の効果，
Ｖ_ｅ：誤差分散，
ｒ：有効序数 をそれぞれ表す。

Here, S: Sensitivity,
S _β : Input effect,
_Ve : Error variance,
r: Represents each effective ordinal number.

B) Test results a) About container shape The SN ratio and sensitivity of the elution amount value for each combination of the shape type of the bottom and bottom of the cylindrical container 9 and the type of crushing media 8 are calculated and shown in the table. The results shown in 2 were obtained.

From the results shown in Table 2, in both the case where the zirconia silica ball (CZS ball) is used as the crushing medium 8 and the case where the glass beads are used, a container having a hemispherical bottom / bottom shape is used. It was confirmed that the SN ratio in the case was larger.

This cause was considered to be related to the fluidity of the mixture of clinker ash and the crushing media 8. That is, it cannot be said that the fluidity of the mixture containing clinker ash is sufficiently good due to the characteristics of the particle shape of clinker ash, and the visual observation result during stirring shows that the bottom and bottom of the container have a conical shape. When (specifically, a conical tube) was used, there were cases where the mixture remained at the lower tip, suggesting that this phenomenon may affect the reproduction accuracy.

Based on the above results, the verification results when a container with a hemispherical bottom / bottom shape is used are shown below.

B) Material and diameter of the crushing media 8 The SN ratio of the elution amount value for each diameter of the crushing media 8 to the official method value was calculated for each material of the crushing media 8 and the result shown in FIG. 2 was obtained. Moreover, the sensitivity was calculated and the result shown in FIG. 3 was obtained. In the examination here, sensitivity is regarded as an index of the elution promoting effect.

From the results shown in FIG. 2, in the calculation result of the SN ratio, the dynamic characteristics are relatively good (that is, high) in the case where the zirconia silica ball (CZS ball) is used as the pulverizing medium 8 and the case where the glass beads are used. It was confirmed that the dynamic characteristics were poor (that is, a low value) when the zirconia ball (YTZ ball) was used. In the evaluation of dynamic characteristics in quality engineering, since the value of the SN ratio is the first selection criterion, it is confirmed from the result of the SN ratio shown in FIG. 2 that the zirconia ball is not suitable as the crushing medium 8 in the present invention. Was done.

Further, from the results shown in FIG. 3, it was confirmed that the sensitivity, which is an index of the elution promoting effect, is the smallest value when zirconia silica balls are used. Regarding the sensitivity, if the sensitivity is too low, it is susceptible to errors in the water quality analysis operation process, while if it is too high, the elution process deviates from the actual phenomenon. It is desirable that the gradient of is around 1 (that is, sensitivity = 0).

From the above, the type of the crushing media 8 is preferably glass beads, and the diameter of the crushing media 8 is preferably in the range of about 0.8 to 2.0 mm, and 1.0 to 1. It was confirmed that the range of about 2 mm is more preferable, and the range of about 1.2 mm is the most preferable.

C) Additional test Glass with a diameter of 1.2 mm as the crushing medium 8 for each of the case where the bottom and bottom 9a of the cylindrical container 9 have a hemispherical shape (in other words, a round bottom) and a conical shape. The beads were used, and the change in the particle size of the coal ash after the treatment with the eccentric vibration device 10 at a rotation speed of 2500 rpm and a stirring time of 90 minutes was verified.

The results shown in FIG. 4 were obtained as changes in the particle size of coal ash after the above treatment for each shape of the bottom and bottom of the cylindrical container 9. The "original particle size distribution" in FIG. 4 is the particle size distribution of coal ash before the vibration stirring treatment.

From the results shown in FIG. 4, crushing with a container having a conical bottom and bottom has a remarkable crushing effect on particles in the range of 20 to 70 μm, and a crushing effect is also seen on particles of 100 μm or more. On the other hand, it was confirmed that crushing with a container having a hemispherical bottom and bottom has a small effect on particles of 100 μm or more and a small crushing effect on particles in the range of 20 to 70 μm.

In the case of a container whose bottom and bottom are hemispherical in shape, the crushing effect of small energy is applied to a wide particle size range, so that it is mild by the dissolution test method specified in Notification No. 46 of the Environment Agency. It was confirmed that a result close to the crushing effect was obtained. This difference is due to the fact that the container with a conical bottom and bottom has a relatively strong compressive force at the inner tip (in other words, the lower end).

(2) Verification of the influence of stirring time and input amount of crushing media A) Test conditions The same 6 samples as those taken up in (1) above (that is, sample numbers 10, 11, 13, 15, 18 in Table 1). , 21), the elution amount was measured after the stirring time of 30 minutes, 60 minutes, and 90 minutes.

Further, glass beads having a diameter of 1.2 mm were used as the crushing media 8, and the elution amount was measured for each of the cases where the input amount of the crushing media 8 was changed in four stages.

B) Test results a) Stirring time The elution amount for each stirring time was measured for each sample, and the result shown in FIG. 5 was obtained as a result of comparison with the value obtained by the official method (that is, the official method value). rice field.

From the results shown in FIG. 5, although the change in the amount of elution over time differs depending on the sample, there are some samples such as the sample of sample No. 10 where the elution is slow, so in order to reproduce the amount of elution equivalent to the official method. It was confirmed that it is preferable to stir for at least 90 minutes.

B) About the input amount of the crushing media 8 (also referred to as "ball amount") The SN ratio and sensitivity of the elution amount value for each input amount of the crushing media 8 to the official method are calculated, and the results shown in Table 3 are obtained. Obtained.

From the results shown in Table 3, when the ball amount is 6.5 g, the SN ratio is close to that when there is no ball (that is, 0.0 g), so that a sufficient stirring / crushing effect is not obtained. confirmed. It was also confirmed that when the ball amount was 13 g, the SN ratio was the largest, and when the ball amount was 19.5 g, the sensitivity increased but the SN ratio decreased slightly.

From the results shown in Table 3, it is predicted that the condition that the ball amount is around 13 g is suitable, but the difference from the result in the case of 19.5 g is small, so the ball amount is 19.5 g. It was confirmed that the conditions in the vicinity were also in a suitable range.

C) Additional test Based on the above results, more test samples (specifically) for the case where the input amount of the glass beads with a diameter of 1.2 mm, which has the best dynamic characteristics, and the crushing media 8 are increased under the same conditions. 18 samples were newly added and the correlation was compared in a total of 24 samples).

The stirring conditions were a rotation speed of the eccentric vibration device 10 of 2500 rpm and a stirring time of 90 minutes, and a centrifuge tube having a hemispherical bottom / bottom surface 9a was used as the cylindrical container 9.

As a comparative case, the correlation with the official method value was obtained for each of the case where the zirconia ball (YTZ ball) having a diameter of 1 mm was used as the crushing medium 8 and the case where the crushing medium 8 was stirred without being charged. Was done.

Correlation with the official method value was obtained for each condition (specifically, type, diameter, input amount) of the crushing media 8, and the results shown in Table 4 were obtained. In addition, "without ball" in Table 4 is a case where the crushing media 8 is not inserted.

From the results shown in Table 4, it was confirmed that the stirring condition in which 13 g of glass beads having a diameter of 1.2 mm was added as the crushing medium 8 showed the highest correlation.

Correlation between the elution amount value and the official method value for every 28 samples in which 4 samples were added under the above stirring conditions was obtained, and the result shown in FIG. 6 was obtained. The "development method elution amount" in FIG. 6 is the elution amount obtained by the elution operation method according to the present invention, and the "official method elution amount" is the elution amount obtained by the official method. .. Further, the broken line in FIG. 6 represents a straight line of x = y (that is, a straight line having a slope of 1 and an intercept of 0).

From the results shown in FIG. 6, ^{it was confirmed that the coefficient of determination r 2 of the} correlation was 0.9814, and the value of the standard error / X coefficient achieved an accuracy of 1.25 μg / L.

(3) Contents of estimation / reproduction method Based on the above results, the elution operation method corresponding to the first step of the method for measuring the amount of heavy metals elution according to the present invention is the elution test specified in Notification No. 46 of the Environment Agency. It was confirmed that the work contents of suitable elution operation conditions when used as a method for estimating (in other words, reproducing) the elution amount obtained by the above are as follows.

i) As the cylindrical container 9, a container having a hemispherical bottom / bottom surface 9a (in other words, a round bottom) (specifically, for example, Cartell, 48 mL capacity round bottom centrifuge tube, model number 306) is used. Then, after the following materials such as the sample 1 to be analyzed are charged, the lid is closed and sealed.

ii) As the sample 1 to be analyzed, 3.5 g of clinker ash whose particle size is adjusted to 2 mm or less after air drying is put into the cylindrical container 9.

iii) As the crushing medium 8, glass beads (material: soda glass) having a diameter of 1.2 mm are put into a 13.0 g cylindrical container 9.

iv) As pure water, etc. 2, 35 mL of pure water is poured into the cylindrical container 9.

v) Eccentric vibration device 10 (specifically, a combination of SI-A286 mixer manufactured by Scientific Industries, USA and a 50 mL centrifuge tube adapter SI-V203 in which a cylindrical container 9 is set and connected to the mixer). Is stirred at a rotation speed of 2500 rpm for 90 minutes.

vi) Immediately after the end of stirring, the contents are filtered by a 0.45 μm membrane filter.

vii) The concentration of arsenic in the filtrate is quantified.

The amount of liquid that can be recovered by the above operation is about 30 to 32 mL.

The eluate obtained by the solution analysis method corresponding to the second step of the method for measuring the amount of heavy metals elution according to the present invention and the elution operation method corresponding to the first step of the method for measuring the amount of heavy metals elution according to the present invention. Examples to verify the validity when used as a method for measuring the concentration of arsenic as a substance to be analyzed will be described with reference to FIGS. 7 to 10.

A) Test method a) Preparation of reagents and solutions i) Standard sample As a standard sample of arsenic (III), arsenic (V), and cobalt, a commercially available reagent prepared at a concentration of 1000 mg / L (specifically, sum in order) Kojunyaku Kogyo 030-16191, Merck Millipore 170303, and Wako Pure Chemical Industries 033-16181) were used, and were appropriately diluted with ultrapure water before use.

ii) 1 w / v% dibenzyldithiocarbamic acid solution (denoted as "DBDTC solution")
Sodium dibenzyldithiocarbamate (specifically, Tokyo Kasei D0156) is dissolved in methanol (specifically, Wako Pure Chemical Industries 131-01826), and a PTFE (polytetrafluoroethylene) membrane having a pore size of 0.2 μm is dissolved. It was used after being filtered with a filter (specifically, a filter unit: ADVANTEC 25JP020AN).

iii) Buffer solution 0.5 mol / L acetic acid / sodium acetate buffer solution (pH 4.0 and pH 5.0) includes acetic acid (specifically, Wako Pure Chemical Industries 017-00256) and sodium acetate (specifically, pH 5.0). , Wako Pure Chemical Industries 192-01075) was used to prepare a 0.5 mol / L acetic acid solution and a 0.5 mol / L sodium acetate solution, which were mixed in appropriate amounts to adjust the pH to 4.0 or 5.0. rice field.

The 0.5 mol / L phosphate buffer (pH 2.0 and pH 3.0) is prepared by mixing an appropriate amount of a 0.5 mol / L phosphate solution and a 0.5 mol / L monosodium hydrogen phosphate solution to pH 2. It was adjusted to 0.0 and pH 3.0.

The 0.5 mol / L MOPS buffer (pH 7.0) and the 0.5 mol / L MES buffer (pH 6.0) are MOPS solution and MES solution with sodium hydroxide at pH 7.0 and pH 6, respectively. It was adjusted to 0 and the final concentration was adjusted to 0.5 mol / L.

iv) Other Reagents For L-Cysteine Hydrochloride Monohydrate and L-Cysteine, commercially available reagents (specifically, Wako Pure Chemical Industries, Ltd. 033-05272, 039-20652, respectively) were used.

b) Measurement operation of arsenic standard sample The amount of the test solution was set to 30 mL in consideration of the amount of eluate obtained by the elution operation method corresponding to the first step of the method for measuring the amount of heavy metal elution according to the present invention. The effects of pH and treatment time during insolubilization were confirmed.

The operation procedure is as follows.
<Procedure 1> Add 2 mL of buffer solution and 1 mL of 10 mg / L cobalt standard solution to 30 mL of arsenic (III) standard sample of 0 to 50 μg / L.
<Procedure 2> After raising the temperature to 30 ° C. in a constant temperature water bath, 1 mL of the DBDTC solution is added with stirring.
<Procedure 3> Leave at 30 ° C. for a predetermined time to insolubilize.
<Procedure 4> The produced insoluble material is recovered with a membrane filter (specifically, pore diameter 0.2 μm, diameter 25 mm; ADVANTEC A020A025A) and washed with ultrapure water.
<Procedure 5> The washed membrane filter is attached to an XRF sample container (specifically, SCP SCIENCE 040-080-046) in advance, and a prolen film (specifically, SCP) in which holes are made in several places with an injection needle. Place on SCIENCE 040-070-045) and air dry for 10 to 15 minutes.
<Procedure 6> The membrane filter is sandwiched between new prolen films and analyzed with an XRF analyzer.

c) XRF analyzer and measurement conditions As the XRF analyzer, specifically, EDXRF-S2 RANGER / LE of Bruker AXS was used. The measurement conditions shown in Table 5 were used. The target of the X-ray tube was Pd, the tube voltage was 50 kV, the tube current was 1000 μA, and Cu with a film thickness of 100 μm was used for the primary filter. The measured X-rays were As (Kα) and Co (Kα) for internal standard correction, and the measurement time was 20 minutes.

d) Calibration curve, detection limit, and lower limit of quantification The relative intensity (I _As / I _Co ) of As (Kα) and Co (Kα) measured by the XRF analyzer is used, and the arsenic (III) concentration of the test solution is used. A calibration curve for W _{As (III)} (specifically, the following equation 4) was created. In the following mathematical formula 4, a is a coefficient and b is a constant.
(Number 4) I _As / I _Co = a · W _{As (III)} + b

The detection limit LOD and the lower limit of quantification LOQ were obtained by the following formulas 5 and 6, respectively, using the slope a of the calibration curve and the standard deviation σ of the residual of the calibration curve.
(Number 5) LOD = 3σ / a
(Number 6) LOQ = 10σ / a

e) Reduction treatment of arsenic (V) According to the previous findings regarding the morphological analysis of arsenic in the coal ash elution test solution, arsenic is mainly detected in the form of arsenic (V) (Seiji Inoba et al. "Coal ash". Examination of elution characteristics of arsenic and selenium in ", Report of Central Research Institute of Electric Power Industry, U03064, 2004), but the existence as arsenic (III) has also been reported (Turner, RR" Oxidation state of arsenic in "Coal ash arsenate", Enbron Sci Technol, 15, 1062-1066, 1981).

Therefore, the arsenic concentration of the eluate obtained by the elution operation method corresponding to the first step of the method for measuring the amount of heavy metals elution according to the present invention needs to be measured as the total of arsenic (V) and arsenic (III). There is. On the other hand, since the conditions for insolubilization by the DBDTC solution are different between arsenic (V) and arsenic (III), it is necessary to reduce arsenic (V) to arsenic (III) in order to measure total arsenic.

L-cysteine was used as the reduction treatment for arsenic (V) (Takeshi Funayama et al., "Visual Separation Analysis of As (III) and As (V) by Solid-Phase Extraction to Membrane Filter", Analytical Chemistry, 62,685-691. , 2013, etc.), the required processing time was verified.

The procedure for measuring arsenic (V) including the reduction treatment is as follows.
<Procedure 1> Add 2 mL of acetate buffer (pH 4) to 30 mL of the standard sample containing arsenic (V).
<Procedure 2> After standing in a constant temperature water bath at 90 to 95 ° C. for 5 to 10 minutes, add 0.2 g of L-cysteine hydrochloride monohydrate or L-cysteine while stirring.
<Procedure 3> Leave it in a constant temperature water tank at 90 to 95 ° C. for a predetermined time.
<Procedure 4> Cool to room temperature in ice water.
<Procedure 5> Add 1 mL of 10 mg / L cobalt standard solution.
<Procedure 6> to <Procedure 10> The same operation as <Procedure 2> to <Procedure 6> in the above "b) Arsenic standard sample measurement operation" is performed.

B) Test results a) Effect of treatment time and pH during insolubilization The results shown in FIG. 7 (A) were obtained for the fluorescent X-ray intensity (denoted as "XRF intensity") for each reaction time in insolubilization with a DBDTC solution. In addition, the results shown in Fig. (B) were obtained for the XRF intensity for each pH.

From the results shown in FIG. 7 (A), it was confirmed that the reaction time (specifically, 5 minutes to 30 minutes) in the carried-out range had almost no effect on the XRF intensity of As (Kα).

From the results shown in FIG. 7 (B), it was confirmed that arsenic (III) obtained a high XRF intensity in the range of pH 2 to pH 6 with respect to the influence of pH, and although there was no large difference, it decreased sharply at pH 7. ..

On the other hand, it was confirmed that arsenic (V) hardly insolubilizes under the conditions of pH 2 to pH 5. Under pH 6 conditions, high XRF intensities were obtained for both arsenic (III) and arsenic (V), but due to the narrow permissible pH range, arsenic was previously measured in order to measure total arsenic in the test solution. It was considered desirable that the reduction of (V) be carried out.

From the above, it was confirmed that the treatment conditions for the chelating agent are preferably set as shown in Table 6.

In this example, the pH was set to pH 4 using an acetate buffer. In the measurement of arsenic (III), it was confirmed that there was no effect in the range of pH 2 to pH 6, but it was confirmed that pH 4 or less is desirable for hexavalent chromium (Isao Watanabe "Sodium dibenzyldithiocarbamate is used as a precipitant". Quantitative analysis of trace chromium (VI) in the ground water by fluorescent X-ray analysis method ”, Analytical Chemistry, 40, T25-T29, 1991, etc.), considering the implementation of multi-elemental analysis with the same sample, pH 4 is considered preferable. Was done.

The cobalt standard solution is added as a co-precipitant to prevent clogging of the membrane filter when filtering the insoluble material, but at the same time, it is used as an internal standard.

b) Calibration curve, detection limit, and lower limit of quantification The calibration curve of the relative intensity (I _As / I _Co ) and arsenic (III) concentration of the fluorescent X-rays of arsenic (III) and cobalt is obtained and shown in FIG. Results were obtained.

From the results shown in FIG. 8, the calibration curve was determined by assuming that the coefficient of determination r ^{2 of the} correlation was 0.99 or more, and a good linear relationship was confirmed.

The lower limit of quantification and the detection limit were calculated from the residual standard deviation of the calibration curve and were 4 μg / L and 1 μg / L, respectively. The lower limit of quantification is 1/2 or less of the Soil Environmental Standard (specifically, 0.01 mg / L or less for As; Environment Agency (at that time) "Environment Agency Notification No. 46" Soil Environmental Standard ", 1991). At least when the selection criteria as a simple analysis method by the Tokyo Metropolitan Government (that is, when the Tokyo Metropolitan Environment Bureau solicited from the general public the analysis technology for heavy metals in the practical stage from 2005 to 2009 regarding the simple analysis method used for soil surveys. It was confirmed that the selection criteria) were met.

In addition, the coefficient of variation measured 5 times with a standard solution of 30 μg / L was 3.3%, confirming that sufficient accuracy was ensured.

The upper limit of 99% of the prediction interval of the regression line is required (Ministry of Health, Labor and Welfare, Pharmaceutical and Food Safety Department, Monitoring and Safety Division, "Radiocesium screening method in food", 2012), and the soil environmental standard value of 0.01 mg / L or less is set. It was derived that it is necessary to secure a quantification of 8.3 μg / L in order to make a judgment. It was confirmed that the limit of quantification was lower than this and that it could be applied to the determination of arsenic in the dissolution test.

c) Analysis of total arsenic by reduction treatment of arsenic (V) L-cysteine can be obtained as a reagent as L-cysteine hydrochloride monohydrate or L-cysteine. When L-cysteine hydrochloride monohydrate is used as a reducing agent, the pH is lowered and there is a concern that the measured value may be affected. However, when the analytical values were compared with those using L-cysteine using a standard solution of 30 μg / L (number of samples n = 4), both analytical values showed an average of 30 μg / L and a standard deviation of 0. It was confirmed that the average deviation was 30 μg / L and the standard deviation was 0.6, which was almost the same as 0.4, and that the analysis value was not affected by any of the reagents. Therefore, since then, L-cysteine hydrochloride monohydrate has been used as a reducing agent for examination.

As an effect of the reaction time on the reduction treatment of arsenic (V), the results shown in FIG. 9 were obtained for the fluorescent X-ray intensity for each treatment time with the reducing agent.

From the results shown in FIG. 9, it was confirmed that the X-ray intensity was high when the processing time was 15 to 25 minutes. The yield at this time was 97.1 to 101.3%, which was sufficiently high, and it was confirmed that the treatment time was sufficient.

In the subsequent reduction treatment of arsenic (V), the reaction time was set to 15 minutes, and the conditions arranged in Table 6 including other conditions were used.

The reduction treatment under the conditions shown in Table 6 was carried out, and measurements of arsenic (III) and arsenic (V) were performed using standard samples, and the results shown in FIG. 10 were obtained. The broken line in FIG. 10 represents a straight line of x = y (that is, a straight line having a slope of 1 and an intercept of 0).

From the results shown in FIG. 10, it was confirmed that for ^{arsenic (V), a high linearity with a slope of 1.005 and a coefficient of determination r 2 of 0.99 or more between the standard sample concentration and the measured value can be obtained.} Was done. In addition, the yield was as high as 103.1% on average, confirming that the reduction treatment was sufficiently performed.

On the other hand, the standard solution of arsenic (III) was similarly reduced, and the slope was 1.041 and the coefficient of determination r ² of the correlation was 0.99 or more, maintaining a high correlation, which affected the measured values. It was confirmed that there was no.

From the above results, it is possible to measure the total arsenic in the test solution by performing a reduction treatment with L-cysteine on the test solution containing arsenic (V) and arsenic (III). confirmed. In addition, it was speculated that by measuring arsenic (III) and then reducing it to measure arsenic (V), it is possible to measure the concentration of arsenic (V) and arsenic (III) by morphology.

When the solution analysis method corresponding to the second step of the method for measuring the amount of heavy metal elution according to the present invention is used as a method for reproducing the concentration of the substance to be analyzed obtained by the analysis method specified in JIS K 0102. An embodiment whose validity has been verified will be described with reference to FIGS. 11 and 12.

A) Test method a) Test solution In this example, 18 types of clinker ash were tested (6 types were conducted with the number of samples n = 2), and elution was performed in accordance with Notification No. 46 of the Environment Agency. The test solution obtained by the test (in other words, the elution operation) was used. Each of the obtained test solutions is a hydride generation ICP emission spectroscopic analysis method (referred to as "JIS official method") based on JIS K0102 and a solution analysis method ("chelating agent collection / XRF measurement method" according to the present invention. The concentration of arsenic was measured by.

b) Analytical procedure In this example, the procedure shown in FIG. 11 was used for the chelating agent collection / XRF measurement method for the arsenic measurement of the clinker ash elution test solution.

The amount of the test solution was 30 mL, and the pH of the test solution was adjusted using the discoloration of methyl orange as an index and used for the measurement of the arsenic concentration.

The operation procedure was set as follows.
<Procedure 1> Add 0.1 mL of 0.1% methyl orange solution (specifically, Wako Pure Chemical Industries, Ltd. 132-10783) to 30 mL of the sample until it turns orange (that is, pH 3 to pH 4). 1 mol / L hydrochloric acid (specifically, Wako Pure Chemical Industries, Ltd. 083-01095) is added.
<Procedure 2> Add 2 mL of 0.5 mol / L acetate buffer (pH 4).
<Procedure 3> to <Example 7> The same operation as <Procedure 2> to <Procedure 6> in "b) Measurement operation of arsenic standard sample" of Example 1 is performed.

B) Test results a) Measurement results of the dissolution test test solution Comparison of the measured values by the chelating agent collection / XRF measurement method and the JIS official method for 24 samples of the dissolution test test solution obtained from 18 types of clinica ash. The results shown in FIG. 12 were obtained. The broken line in FIG. 12 represents a straight line of x = y (that is, a straight line having a slope of 1 and an intercept of 0).

From the results shown in FIG. 12, a ^{straight line having a slope of 1.03 and a coefficient of determination r 2} of 0.993 was obtained for the correlation between both measured values, and a high correlation was confirmed.

b) Applicability to elution operation method and screening level The chelating agent collection / XRF measurement method is applied to arsenic analysis in combination with the elution operation method corresponding to the first step of the method for measuring the amount of heavy metals elution according to the present invention. It is desirable that the screening level be set in consideration of the error caused by the chelating agent collection / XRF measurement method when it is used for the discrimination of the clinica ash.

However, since the amount of the test solution obtained by the elution operation method according to the present invention is small, the test solution cannot be used for analysis of both the chelating agent collection / XRF measurement method and the JIS official method.

Therefore, the regression lines of FIGS. 6 and 12 are used, and the elution when the chelating agent collection / XRF measurement method is applied to the arsenic analysis of the eluate obtained by the elution operation method according to the present invention by the Monte Carlo method. A measured value of arsenic concentration was estimated in which the upper limit of 99% of the arsenic concentration distribution in the liquid was 0.01 mg / L.

Estimates from each regression line were assumed to follow a normal distribution with a standard deviation s calculated by Equation 7 below (Miller J Net al., Translated by Shin Somori et al. 2nd Edition ”, Kyoritsu Publishing, 2004).

ここに、 ｓ：標準偏差，
ｓ_y/x：回帰直線の残差の標準偏差，
ａ：回帰直線の傾き，
ｎ：試料数，
ｙ₀：測定値，
ｙ￣(正しくは、ｙの直上に￣が付く)：回帰直線の試料測定値の平均，
ｓ_xx：回帰直線の試料公定法値の平方和 をそれぞれ表す。

Here, s: standard deviation,
_{sy / x} : Standard deviation of regression line residuals,
a: Slope of regression line,
n: number of samples,
y ₀ : measured value,
y￣ (correctly, ￣ is attached directly above y): Average of sample measurements on the regression line,
s _xx : Represents the sum of squares of the sample official values of the regression line.

Measurement by chelating agent collection / XRF measurement method in which a random number of 100,000 repetitions is generated and the 99% upper limit of the arsenic concentration in the dissolution test specified in Notification No. 46 of the Environment Agency is 0.01 mg / L. The value was estimated. As a result, the measured value by the chelating agent collection / XRF measurement method required for the discrimination of clinker ash was estimated to be 5.7 μg / L. At this time, the average arsenic concentration of the elution operation method according to the present invention was 5.5 μg / L (note that the concentration is equivalent to 6.4 μg / L when converted to the official value of the Environment Agency by the regression equation). .. It was confirmed that this measured value is within the range that can be quantified by the chelating agent collection / XRF measurement method.

From the above results, it was confirmed that the chelating agent collection / XRF measurement method can be applied to the discrimination of clinker ash in combination with the elution operation method according to the present invention.

The method for measuring the elution amount of heavy metals according to the present invention is a method for surely discriminating a sample having an elution amount smaller than the soil environmental standard value (that is, 0.01 mg / L) for the cleanse ash at the time of shipment (that is,). , The example which verified the validity when it was used as the screening method of Clinker ash) will be described.

The value of the elution amount obtained by the elution test specified in Notification No. 46 of the Environment Agency by the method for measuring the elution amount of heavy metals according to the present invention for the cleanser ash samples having different properties (“Official value of the Environment Agency”). When the prediction accuracy of) is taken into consideration, variations due to the elution operation as well as variations due to the variety of sample properties are included as error factors. The screening level is evaluated using the upper limit of the prediction interval of the regression line in order to consider the influence of these variations.

Based on the elution amount data of the 28 types of Clinker Ash test samples shown in Table 1 above, the upper limit of 95% (that is, the risk rate 5%) of the prediction interval of the regression line is obtained, and it is standardized by the official law value of the Environment Agency. Value 10 μg / L The screening level for discriminating the sample is 6.4 μg / L in the analysis value of the elution operation method corresponding to the first step of the method for measuring the amount of heavy metal elution according to the present invention (note that). , It was confirmed that the concentration is equivalent to 7.4 μg / L when converted to the official value of the Environment Agency by the regression equation).

Similarly, the screening level obtained from the upper limit of the predicted interval of 99% (that is, the risk rate of 1%) is 5.5 μg / L (note that when converted into the official value of the Environment Agency by the regression equation, 6. It was confirmed that the concentration was equivalent to 5 μg / L).

Furthermore, for each of the three test samples showing an elution amount in the range of 4 to 6.5 μg / L, which is close to these screening levels, the following implementation conditions (in addition, the official method value is estimated / reproduced) 7 times each. As a result of the elution operation according to (one of the suitable implementation conditions), the detection limit (MDL) of the arsenic elution amount value under the following implementation conditions is 0.8 to 0 in any sample. It was 1.7 μg / L and the lower limit of quantification (LOQ) was in the range of 2.7 to 5.4 μg / L. The detection limit MDL was calculated by the following formula 8, and the lower limit of quantification LOQ here was calculated by the following formula 9.

(Equation 8) MDL = T _{(n-1,1-α = 0.99)} · (S)
(Number 9) LOQ = 10 ・ (S)
Here, MDL: detection limit,
LOQ: Lower limit of quantification,
T: Student's t-value
(Here, the degree of freedom: number of samples n-1, 99% confidence level),
S: Represents the sample standard deviation.

<Implementation conditions for screening level verification>
i) Crushing media 8: Glass beads with a diameter of 1.2 mm, 13 g
ii) Stirring conditions: Stirring time is 90 minutes due to eccentric vibration at a rotation speed of 2500 rpm.
iii) Cylindrical container 9: Cylindrical container with a hemispherical shape at the bottom and bottom 9a (specifically, a round-bottom centrifuge tube with a capacity of 48 mL)

Since the lower limit of quantification is below the screening level, the result of the elution operation method (particularly, at least the operation under the above-mentioned implementation conditions) corresponding to the first step of the method for measuring the amount of heavy metals elution according to the present invention is the soil environment. It was confirmed that it can be applied to the screening of cleanse ash corresponding to the standard value.

1 Sample to be analyzed 2 Pure water, etc. (pure water, ultrapure water, elution solution)
8 Crushing media 9 Cylindrical container 9a Bottom / bottom surface 9b Lid 10 Eccentric vibration device

Claims (10)

Into a cylindrical container with a hemispherical bottom that has a closed bottom,
A sample to be analyzed having a particle size of 5 mm or less and water or an elution solution are added, and the sample is added.
Add crushing media with a particle size of 0.1 to 10 mm,
The cylindrical container is vibrated by the eccentric rotation given by the eccentric vibration device to vibrate and stir the contents in the cylindrical container.
A method for measuring the amount of heavy metals eluted, which comprises obtaining an eluate from which heavy metals contained in the sample to be analyzed have been eluted. The method for measuring the amount of heavy metals eluted according to claim 1, wherein the sample to be analyzed is at least one of coal ash, incinerated ash, slag, and cement solidified product of coal ash and incinerated ash. .. The method for measuring the amount of heavy metals eluted according to claim 1, wherein the particle size of the crushing medium is in the range of 0.5 to 3 mm. The method for measuring the elution amount of heavy metals according to claim 1, wherein the specific gravity of the crushing medium ^{is in the range of 1.0 to 4.3 g / cm 3.} The inner diameter of the cylindrical container is in the range of 15 to 40 mm, the sample to be analyzed is in the range of 2 to 20 g, and the water or the elution solution is in the range of 20 to 200 mL. The method for measuring the amount of heavy metal elution according to claim 1, wherein the ratio is 10 L / kg. The orbit diameter for eccentric rotation is in the range of 3 to 5 mm, the rotation speed of the eccentric rotation is in the range of 1000 to 3000 rpm, and the time is in the range of 20 to 120 minutes. The method for measuring the amount of heavy metal elution according to claim 1. A fluorescent X-ray elemental analysis method after adding a reducing agent to the eluent, adding a chelating agent, filtering with a filter to collect the heavy metals, and drying the filter containing the heavy metals. The method for measuring the amount of elution of heavy metals according to claim 1, wherein the arsenic content is quantified by means of. The method for measuring the amount of heavy metals eluted according to claim 7, wherein L-cysteine is used as the reducing agent. The method for measuring the amount of heavy metals eluted according to claim 7, wherein a 1% DBDTC solution is used as the chelating agent. The method for measuring the amount of heavy metal elution according to claim 7, wherein the pH of the eluate is adjusted using the discoloration of methyl orange as an index.

Images