JP2019090786A - Method for quantifying single metal in metal oxide - Google Patents

Abstract

To provide a method enabling a single metal in a metal oxide to be selectively detected with high sensitivity, and enabling the single metal to be quantified with high degree of accuracy, the metal oxide containing the single metal of 10 ppm or less.SOLUTION: The method for quantifying a single metal in a metal oxide is provided that includes the steps of : melting a single metal in a metal oxide by a bromine-methanol melting method, and extracting the single metal to solution; separating the solution where the single metal is extracted, from an unmelted object; evaporating, drying and solidifying the solution in which the single metal is extracted; adding acid to the dried and solidified object generated by evaporation, drying and solidification to make it into a solution state; and quantifying the single metal in the solution in which the dried and solidified object is made into the solution state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of quantifying a single metal in a metal oxide.

Various types of metal oxides are widely used in various technical fields as raw materials for substrate materials, dielectric materials, magnetic materials and battery materials used in electronic devices. However, in the production process of the metal oxide, various elements may be mixed as impurities, though in a small amount.
Among the elements to be mixed, when a metal oxide containing a single substance of various metal elements as an impurity is used as a raw material of the above-described various materials, even if the metal single substance contained is a trace amount It may have an adverse effect. For this reason, it is important to quantify and grasp the content even if the metal simple substance contained in the metal oxide is a trace amount.
In the present invention, "a single metal" refers to a metal in a state of being composed of a metal without forming a compound, and "a single M (wherein M is an elemental symbol of a metal)" means a compound. It is M metal which is in a state of metal M without being formed.

  Conventionally, there is no method for quantifying trace metals contained in metal oxides, which has been established as a standard. However, as an analysis method of a metal element, there is, for example, Non-Patent Document 1. In addition, Non-Patent Document 2 describes a method of determining metal Ni contained in nickel oxide.

In inductively coupled plasma atomic emission spectrometry (ICP-OES method), which is the most versatile analysis method described in Non-Patent Document 1, metal Al contained in the sample to be analyzed is dissolved with halogen, and metal Al is dissolved. Separates the solution and the residue extracted into the solvent. Then, the solvent is evaporated from the metal Al solution to dryness to obtain a dried product. The resulting dried product is acid-decomposed to form an acid solution, and the acid solution is prepared by dilution and quantified by ICP-OES method.
Non-Patent Document 1 describes that the quantitative range of inductively coupled plasma emission spectrometry in the analysis method is about> 1% by mass, and that the method is a simple and effective method at a normal analysis level.

  In Non-Patent Document 2, metal Ni solution and residue are separated by dissolving metal Ni with halogen and extracting it into a solvent without dissolving nickel oxide which is the main component of the sample to be analyzed. It is described that the operation of separating the metal Ni solution and the residue quantitatively analyzed metal Ni contained in nickel oxide in the range of 0.1 to 70% by mass.

Japanese Mining Standard JIS G 2402 (2009) "Determination of Al in steel and aluminum dross" Analytical chemistry: Vol. 23 (1974) "Determination of intervening metal Ni in nickel oxide"

  The present inventors examined the application of the quantification method described in Non-Patent Documents 1 and 2 as a method of quantifying a trace amount of metal simple substance contained in the metal oxide. However, it has been found that even if the quantitative method described in Non-Patent Documents 1 and 2 is applied, the trace metal simple substance contained in the metal oxide can not be quantified well.

  First, when the quantitative method described in Non-Patent Document 1 is applied and, for example, Cu simplex is selected as the metal simplex, the detection sensitivity of the Cu simplex is low. Therefore, it was found that it is difficult to determine the concentration of Cu alone when the amount of Cu alone contained in the metal oxide is 50 ppm or less.

  On the other hand, when the quantitative method described in Non-Patent Document 2 is applied, for example, a simple substance of Cu is selected as a simple substance of metal, and a simple substance of Cu is dissolved in halogen and extracted in a solvent, the halogen also dissolves the metal oxide, The main component concentration of the predetermined metal constituting the metal oxide has become high. Therefore, it was found that it is difficult to determine the concentration of Cu alone when the amount of Cu alone contained in the metal oxide is 10 ppm or less.

  The present invention has been accomplished under the above-described circumstances, and the problem to be solved is to selectively detect the metal simple substance with high sensitivity in the metal oxide containing the metal simple substance of 10 ppm or less. It is possible to provide a method that can be quantified accurately.

  The present inventors have conducted research in order to solve the above-mentioned problems. As a result, attention was focused on the concentration of a bromine methanol solution for dissolving and extracting a metal component containing a trace metal simple substance contained in the metal oxide which is an analysis target sample. Then, the metal oxide that occupies most of the metal oxide sample that is the analysis target sample is separated and discarded as a residue, and the concentration of the main component derived from the metal oxide can be reduced in the obtained solution. It was found that a bromine methanol solution concentration was present.

  Furthermore, the present inventors conceived of inductively coupled plasma mass spectrometry (ICP-MS method) capable of detecting a single metal with high sensitivity. The analysis method is subject to the restriction that the main component concentration that can be measured is (<1 g / L), but it is an applicable method as long as the main component concentration in the sample to be analyzed can be reduced.

  Based on the above findings, the present inventors obtained a metal oxide occupying most of the metal oxide sample to be analyzed as a residue using the methanol solution of bromine set to a predetermined concentration as a residue, and was discarded. The solvent of the solution containing elemental metal is evaporated to obtain a dried product. Then, it has been found that, by measuring the solution obtained by dissolving the dry matter in an acid form into a solution by ICP-MS method, it is possible to quantify a trace metal simple substance contained in the metal oxide which is a sample to be analyzed. The present invention has been achieved.

That is, the first invention according to the present invention is
A method of quantifying a metal simple substance in a metal oxide containing a metal simple substance of 10 ppm or less, comprising
Dissolving the metal simple substance in the metal oxide by a bromine-methanol dissolution method, and extracting the metal simple substance into a solution;
Separating the unmetallized solution and the solution from which the metal single substance is extracted;
Evaporating the solution obtained by extracting the metal alone to dryness;
Acidizing the solution obtained by the evaporation to dryness;
And D. determining a single metal in a solution in which the dried material is made into a solution, the method of determining a single metal in the metal oxide.
The second invention is
The bromine concentration in the bromine methanol solution used in the bromine-methanol dissolution method is 0.2 M or more and 0.4 M or less. This is a method for quantifying a metal simple substance in a metal oxide.
The third invention is
The method further comprises the steps of adding an internal standard substance to the solution and quantifying the volume with pure water when quantifying the metal simple substance in the solution in which the dried product is made into a solution. It is a method of quantifying a single metal.
The fourth invention is
When quantifying the metal simple substance in the solution, it is a quantitative method of the metal simple substance in the metal oxide characterized by quantifying the metal simple substance quantity using inductively coupled plasma mass spectrometry (ICP-MS method) .
The fifth invention is
It is a method of quantifying a metal simple substance in a metal oxide characterized in that the metal simple substance is a Cu simple substance.
The sixth invention is
The metal oxide is a metal oxide containing 10% by mass or more of Ni.

  According to the method for quantifying a single metal in a metal oxide according to the present invention, a single metal of 10 ppm or less contained in the metal oxide can be selectively detected with high sensitivity and can be quantified became.

FIG. 5 is an operation flow diagram showing a method of quantifying a trace amount of Cu simple substance contained in a metal oxide according to Example 1.

  In the method for quantifying a single metal in a metal oxide sample according to the present invention, a single metal in the metal oxide sample is dissolved and extracted using a bromine methanol solution, and the remaining metal oxide is separated as a residue , To discard. That is, by dissolving and extracting a simple metal from a metal oxide sample, the simple metal can be selectively detected with high sensitivity, and quantitative determination can be performed with relatively high accuracy.

  Hereinafter, the method for quantifying a single metal in the metal oxide according to the present invention, (1) sample preparation place for metal oxide sample, (2) metal oxidation, taking as an example the case where Cu single is used as the single metal Method of washing dissolution sample and waste tube, (3) weighing method of metal oxide sample, (4) dissolving and extracting method of metal single body by bromine-methanol dissolution method, (5) extraction solution and metal oxide residue And (6) drying the solution, dissolving the dried product, (7) preparing a sample solution for measurement, (8) measuring the concentration of a single metal, (9 ) Summary, will be described in the order.

(1) Sample preparation place of metal oxide sample As a sample preparation place of the metal oxide sample according to the present invention, it is preferable to use a clean room of CLASS 1000 level, but usually there is little usage history of metal species to be analyzed. It is also possible to use a laboratory of

(2) Dissolution container of metal oxide sample and washing method of centrifuge tube As a dissolution container of metal oxide sample, a sealable container made of PP (polypropylene) or Teflon (registered trademark) is preferably applicable . In addition, as with the sample dissolution vessel, a vessel with a sealable volume scale made of PP or Teflon (registered trademark) is preferably applicable to the centrifuge tube as well.
After washing the container and the lid about 10 times with ultrapure water, it is preferable to store the container and the lid immediately in a state of being covered.

(3) Weighing Method of Metal Oxide Sample After weighing a metal oxide sample in the sealable dissolution container described above, the lid is attached and the mass (g) of the sample is weighed and recorded with an electronic balance. In addition, it is preferable to use the electronic balance which can measure to 0.1 mg for the measurement of the said test metal oxide material.

(4) Dissolution and Extraction Method of Simple Metal by the Bromine-Methanol Dissolution Method In the present invention, the so-called bromine-methanol dissolution method refers to so-called bromine in various metal simple substance including Cu simple substance and Fe simple substance in metal oxide sample. It is a method of dissolving and extracting with methanol solution.
The bromine methanol solution concentration is a concentration at which the metal simple substance to be analyzed can be dissolved without dissolving the metal oxide.
For example, when Cu single substance is to be analyzed, it has been found that the concentration of bromine in the bromine methanol solution is preferably 0.2 to 0.4 M, more preferably 0.2 M, as a concentration at which the Cu single substance can be dissolved. (However, in the present invention, the unit M means mol / L).
The bromine methanol solution of the said concentration is added to the metal oxide sample in the dissolution container mentioned above, and it is immediately covered. Then, the apparatus is set on an ultrasonic cleaner for 60 to 120 minutes to dissolve the metal simple substance in the metal oxide sample in the extraction solution and extract it from the metal oxide sample.

(5) Method of separating extraction solution and metal oxide residue into solution and undissolved matter The obtained extraction solution is filtered using a filter, and the filtrate is subjected to the above-mentioned centrifuge tube. On the other hand, the residue collected on the filter is discarded. In addition, as a filter, a Teflon filter is preferable, and if it is a thing which does not contain metal species which are analysis object, it can be used without particular limitation.

(6) Drying method of solution, dissolution method of the dried matter The filtrate received in the above-mentioned centrifuge tube is heated at 80 to 120 ° C. to completely volatilize the bromine methanol solution as the solvent until the solute is dried. After being allowed to cool.
When the cooling is completed, ultrapure water and nitric acid are subsequently added to the centrifuge tube and heated, and the resulting dried solid is completely dissolved and then allowed to cool.
At the time of dissolution of the dry matter, the amount of acid addition may be an amount that can sufficiently dissolve the dry matter. In addition, it is convenient to use a hot plate or the like for heating.
As the nitric acid, it is preferable to use a high purity reagent whose guaranteed value of metal species to be analyzed is 20 ppt or less. In the present invention, "nitric acid" is a nitric acid solution having a concentration of 14M.

(7) Preparation of Measurement Sample Solution After adding a fixed amount of the internal standard substance solution to the solution of the above-mentioned dry matter, ultrapure water is added and the volume is adjusted to obtain a measurement sample solution.
For example, in the case where Cu alone is to be analyzed, for example, Y (yttrium, concentration: 1000 ng / ml) is preferable as the internal standard substance solution.

(8) Measurement Method of Single Metal Concentration It is convenient to use an ICP-MS apparatus to measure the single metal concentration in the measurement sample solution described above. Therefore, hereinafter, with regard to the measurement of metal single substance concentration in the measurement sample solution using the ICP-MS apparatus, 1) preparation of standard sample solution, 2) measurement of metal simple substance concentration by ICP-MS apparatus, 3) calculation of metal simple substance concentration The method will be described in order.

1) Preparation of a Single Metal Measurement Standard Sample Solution A standard sample solution is prepared according to the concentration of a single metal to be analyzed in a measurement sample solution. At this time, the acid concentration contained in the standard sample solution and the metal concentration to be analyzed are prepared to be equivalent to the acid concentration in the measurement sample solution and the metal single substance concentration to be analyzed.
For example, in the case where Cu alone is to be analyzed, it is convenient to prepare a Cu standard sample solution by appropriately diluting a commercially available 1 g / L Cu standard sample solution. Then, it is preferable to prepare multiple types of standard sample solutions in order to make multiple concentration levels uniform.

2) Measurement of Single Metal Concentration by ICP-MS Apparatus The mass number of the metal concentration to be analyzed by the ICP-MS apparatus is not particularly limited as long as there is no interference with coexistent elements. In addition, for other measurement conditions, it is preferable to use the conditions recommended by the measurement device manufacturer.
For example, in the case where Cu alone is to be analyzed, it is preferable to use the most sensitive mass number 65. On the other hand, it is preferable to use 89 as the measured mass number of Y, which is an internal standard substance, and to measure by the internal standard correction method.
Then, in the measurement sample solution and the metal standard sample solution to be analyzed using the ICP-MS apparatus, the single metal concentration to be analyzed is measured, and the metal simple substance to be analyzed in the measurement sample solution from the measured value. Calculate the content (ng) of
The ICP-MS apparatus to be used is not particularly limited. For example, Agilent 7500cs manufactured by Agilent Technologies Co., Ltd., iCAP Q ICP-MS manufactured by Thermo Fisher Scientific Co., Ltd., and the like can be mentioned.
In the case where the Cu concentration was measured by the measurement sample solution and the Cu standard sample solution using an ICP-MS apparatus, the Cu concentration in the measurement sample could be quantified up to 20 ppb (20 ng / g).

3) Calculation Method of Single Metal Concentration Based on the single metal content (ng) in the measurement sample solution measured by ICP-MS, the single metal concentration in the measurement sample solution is calculated using Formula 1.
A ₁ = (A ₂ / W) ··· Formula 1
However, A ₁ : Concentration of elemental metal in the sample solution for measurement (ppb)
A ₂ : Content of single metal in the measurement sample solution (ng)
W: amount of sample solution to be measured (g)

(9) Summary As described above, if the method of quantifying a single metal in a metal oxide sample according to the present invention is used, the analysis target up to 50 ppm or less, and further several tens ppb level contained in the metal oxide sample It was possible to selectively detect the metal simple substance with high sensitivity, and to quantify accurately. As a result, the method for quantifying a trace metal single substance contained in the metal oxide according to the present invention is versatile in various technical fields as a raw material for substrate materials, dielectric materials, magnetic materials and battery materials. It has been found that it can be suitably used for grasping and managing the concentration of a single metal in the metal oxide used for

  Hereinafter, the present invention will be more specifically described with reference to examples. However, the present invention is not limited to the following examples.

Example 1
A present Example is an example at the time of selecting Cu single-piece | unit as a metal single-piece | unit which is analysis object.
Hereinafter, referring to an operation flow chart showing a method of determining a trace amount of Cu alone contained in the metal oxide (in the present embodiment, Ni oxide) according to Example 1 shown in FIG. The method of quantifying a trace amount of Cu contained in the substance is described.

A 50 mL PP container was prepared, and after the container and the lid were washed 10 times with ultrapure water, the container was immediately stored with the container covered.
Ni oxide samples (A to C) Weigh each 2 g (Nos. 1 to 3) into each of the above-mentioned sealable dissolution containers, cover it, and weigh the mass (g) of the sample with an electronic balance. did.
Add 20 mL of 0.2 M bromine methanol solution to the metal oxide sample in the dissolution vessel described above and immediately cap. Then, it was set on an ultrasonic cleaner for 60 minutes to dissolve Cu simple substance in the metal oxide sample in the extraction solution and extract it from the metal oxide sample.
The 0.2 M bromine methanol solution is prepared by adding 5 mL of bromine solution to 495 mL of methanol solution.
The obtained extract solution was filtered using a 0.45 μm Teflon filter, and the filtrate was put into a 50 mL PP centrifuge tube. On the other hand, the residue collected on the Teflon filter was discarded.
The filtrate received in the centrifuge tube was heated at 80 ° C. on a hot plate to completely volatilize the bromine methanol solution as a solvent, heated until the solute became dry, and then allowed to cool.
After cooling was complete, 5 mL of ultrapure water and 0.5 mL of 14 M nitric acid solution were added to the centrifuge tube and heated on a hot plate at 80 ° C. to completely dissolve the resulting dried solid. Then it was allowed to cool.
After adding 0.1 mL of Y (yttrium, concentration: 1000 ng / ml) solution as an internal standard substance to the solution of the obtained dried product, ultrapure water was added and the volume was adjusted to 10 mL to obtain a measurement sample solution .
Here, 1 mg of metal Cu was weighed and added to the Ni oxide sample A after sample weighing. And the recovery rate of the added metal Cu was also measured.

The measured mass number of the Cu concentration by the ICP-MS apparatus was 65. On the other hand, the measured mass number of Y was 89 and was measured by the internal standard correction method.
And Cu concentration is measured in a measurement sample solution and Cu standard sample solution using an ICP-MS apparatus, and content (ng) of Cu simple substance in a measurement sample solution is computed from the measurement value concerned.
The ICP-MS apparatus used was Agilent 7500 cs manufactured by Agilent Technologies.
By the above operation, the amount of elemental Cu in each sample was quantified. The quantitative results are shown in Table 1.

On the other hand, four blanks (BL. 1 to 4) are prepared to calculate the lower limit of quantification of the method for quantifying Cu alone in the metal oxide sample according to this example, and the Ni oxide sample (A) described above is prepared. In parallel with the analysis of-C), a blank test was performed.
Table 2 shows the results of calculation of the blank test results, standard deviation, 10σ, and lower limit of quantification.

  From the results of Table 1, it is assumed that the repeat accuracy of three in parallel (No. 1 to 3) in each sample of the Ni oxide sample is sufficient in quantitative analysis of several tens ppb level. Moreover, since the addition recovery rate of Cu single-piece | unit was as favorable as 89%, it turns out that this method has quantified accurately.

  From the results of Table 1 and Table 2, the method for quantifying a trace amount of Cu alone in the Ni oxide of the present embodiment is highly sensitive and accurate with which the concentration of Cu alone in the sample can be quantified to about 20 ppb. It can be understood that it is a quantitative method.

From the above, according to the method of quantifying Cu alone contained in the Ni oxide according to this example, Cu singles of several 10 ppb level contained in the sample can be detected with high sensitivity and compared. Quantitative analysis became possible with high accuracy. Accordingly, it is effective as a method of monitoring the concentration of elemental Cu in Ni oxide used in the field of substrate materials and the like.

Claims (6)

A method of quantifying a metal simple substance in a metal oxide containing a metal simple substance of 10 ppm or less, comprising
Dissolving the metal simple substance in the metal oxide by a bromine-methanol dissolution method, and extracting the metal simple substance into a solution;
Separating the unmetallized solution and the solution from which the metal single substance is extracted;
Evaporating the solution obtained by extracting the metal alone to dryness;
Acidizing the solution obtained by the evaporation to dryness;
Determining the metal simple substance in a solution obtained by dissolving the dried matter in solution, the method of quantifying the metal simple substance in the metal oxide.   The method according to claim 1, wherein the bromine concentration in the bromine methanol solution used in the bromine-methanol dissolution method is 0.2 M or more and 0.4 M or less.   The method further comprises the steps of adding an internal standard substance to the solution and quantifying with pure water when quantifying the metal simple substance in the solution of the dried product in solution. The method of quantifying a single metal in the metal oxide as described in 4.   The metal according to any one of claims 1 to 3, wherein the amount of the metal simple substance is quantified using inductively coupled plasma mass spectrometry (ICP-MS method) when the metal simple substance in the solution is quantified. Method for quantifying simple metals in oxides.   The method for quantifying a metal simple substance in a metal oxide according to any one of claims 1 to 4, wherein the metal simple substance is a Cu simple substance.   The method according to any one of claims 1 to 5, wherein the metal oxide is a metal oxide containing 10% by mass or more of Ni.

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