JPS59198346A - Quantitative analysis of silicon in barium titanate by plasma light emitting spectroscopic method - Google Patents

Abstract

PURPOSE:To perform the quantitative analysis of Si in BaTiO with good accuracy within a short time, by a method wherein a specimen BeTiO3 and concn. hydrochloric acid are added to a pressure crucible and heated therein to separately take a hydrochloric acid solution and a precipitate while the precipitate is dissolved in an HF solution and Si in both solutions is measured by a plasma light emitting spectroscopic method. CONSTITUTION:A predetermined amount of conc. hydrochloric acid is added to a definite amount of a specimen BaTiO3 and the resulting mixture is put in a Teflon beaker 2 which is, in turn, introduced into a stainless container 3 while a Teflon lid 4 is applied and the beaker 2 is hermetically sealed by a screw 5 to dissolve said specimen at 150 deg.C for 6hr. After cooling, the obtained solution is filtered under vacuum by using a Teflon filter for a liquid chromatograph and a funnel and Si in the filtrate is subjected to plasma light emitting spectroscopic analysis. The precipitate, the funnel and the filter are dissolved and washed in a polyethylene beaker by an HF solution while the HF solution is filtered by the aforementioned Teflon filter 7 to be combined with the washing liquid. After H3BO4 is added to the MF solution to mask HF as BF<->, Si in this solution is subjected to plasma light emitting spectroscopic analysis. By this method, the mixing of Si from an analytical instrument is eliminated and an accurate Si- amount is subjected to quantitative analysis from the sum of Si in both liquids of the hydrochloric acid solution and the HF solution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for quantitatively analyzing silicon in barium titanate using plasma emission spectroscopy.

Conventionally, in quantifying elements such as silicon in ceramics such as barium titanate (BaTiOs), the absorption 4 degree method, as shown in FIG. 1, has been mainly used. In these conventional analysis methods, pretreatment for measurement by the absorption 4 degree method is very complicated and takes a long time.

For example, when manufacturing a product using BaTiO3 as a manufacturing raw material, qualitative and quantitative analysis of impurities and additives in BaTiOs is necessary for process control and product control. To this end, there was a need to establish a highly accurate analytical method, but the conventional spectrophotometric method required too much time for analysis and could not meet the above requirements.

The present invention satisfies the above requirements by adopting plasma emission spectroscopy instead of the conventional method.

Plasma emission spectroscopy has the advantage that compared to conventional methods, direct quantitative analysis can be performed simply by dissolving the sample, so the time required for analysis is short, and it is difficult to introduce errors. Moreover, anyone can perform the measurement without requiring any skill unlike conventional methods.

The present invention is applicable to analyzing silicon in barium titanate.
The purpose of this study is to provide a method for quantitative analysis using plastron spectroscopy.

The present invention will be described below based on examples and findings obtained.

First, a method for dissolving a sample will be described when silicon in barium titanate is analyzed by plasma emission spectroscopy using an inductively coupled radio-frequency argon plasma emission spectrometer (hereinafter referred to as RCP).

(1) About dissolving the sample In order to collect and dissolve a certain amount (0.5 g) of the sample in the present invention, a pressurized crucible consisting of a stainless steel container 1 and a Teflon container part 2 as shown in Fig. 2 is used. Place the sample in the Teflon part 2 of No. 6, add a certain amount (20 mt) of #hydrochloric acid, and place the sample in the container 2.
The mixture is placed in a stainless steel container 1, sealed with a Teflon lid 4 with a screw 5, and heated at a temperature of 150° C. for 6 hours.

6 in the figure is a stirrer. However, in order to sufficiently dissolve the sample, the 6-hour heating time is repeated by heating for 1 hour, stirring for 30 minutes on a star sea, and heating for 1 hour. However, this operation produces a white precipitate in the solution.

As a result of fluorescent X-ray examination, only St and a trace amount of T1 were detected.

This can be presumed to be titania and SiO2. In addition, as a result of examining the solution side by ICP, it was found that in addition to a large amount of Th * Ba, it also contained a trace amount of Si. All of the St in the sample was not precipitated as SiO
It is thought that it is dissolved in the l-solution.

In order to analyze by ICP, 5iOzf must be dissolved, so 1(F), which is generally used as a decomposition reagent for Sin:, was added to the sample solution.

However, a large amount of white precipitate was formed, and Xa! Diffraction analysis revealed that it was a BaTiFe precipitate.

(2) Recovery method as described above (in a state where Ti and Ba coexist)
``When e is added, a large amount of BaTiF6 precipitate is dissolved, so the sample, including Si, cannot be dissolved in the same tube. Therefore, conversely, all the Si is dissolved in the form of 5i02 precipitate. Consider how to recover it in the hole.

Width White smoke treatment with perchloric acid (H, cLO41) During the dissolution of the sample mentioned above, it was found that the sample HcL solution also contained St. By oxidizing this 8i, Si
In order to obtain a precipitate of 02, white smoke treatment with I(cAO4 was attempted).

First, put the sample dissolved in Hct into a glass flask together with the precipitate of 5i02, cover it with a watch glass, and warm it over low heat using a burner until the liquid becomes less. If about 10 mt is added and heated again.

After that, if white smoke comes out in the beaker, turn off the burner. At this point, a large amount of precipitate is generated, so in order to redissolve elements other than 5io2, a certain amount of HCl (20 mL
) and heat.

However, in reality, a large amount of Ti and Ba oxides are converted back into Hc.
It was impossible to separate only 5102 as it remained as a precipitate without being dissolved in the solution.
Evaporation to dryness was performed to recover as n2.

Pour all of the solution into a glass flask in the same way as in (i), cover with a watch glass, and heat over low heat.

Immediately after the liquid was completely evaporated, the remaining precipitate was dried under strong heat, and after the fire was turned off, HcL was added again in an attempt to obtain only 5i02 by precipitation. However, similar to the width, a large amount of Ti*Ba oxide remains as a precipitate, making it impossible to recover only 5io2.

(3) St constant force method from each P solution and precipitate.
Since it is difficult to quantify all Si at the same time, we decided to separate 5 t (h) of precipitate from the sample HcL solution in a furnace and quantify the Si contained in both the filtrate and the precipitate. Alternative methods and dissolution methods were investigated.

(i) Method using a glass funnel, a polyethylene funnel, and 5CF paper The sample solution was filtered using an ordinary 45φ glass funnel and 5CF paper. At that time, if the solution was poured directly from the pressurized crucible onto the filter paper, the acidity would be too high and the filter paper would tear, so the liquid in the pressurized crucible was diluted with water in advance and then filtered. In addition, HF, which is a decomposition reagent for SiO□, dissolves glass products, and St is mixed in from there.
All equipment that comes into contact with HF is made of synthetic resin (polyethylene,
Teflon etc.) must be used frequently.

After filtering the sample solution, put the precipitate of Sin along with the filter paper into a polyethylene beaker and add a certain amount of HF (1 volume of HF plus 9 volumes of water, hereinafter referred to as (1+9)) (20 mA).
) to dissolve. At this time, in order to improve the recovery rate of Si, the P abrasive was coated with polyethylene and stirred well with a bulb-shaped ice cube. The idea was to filter it again through a polyethylene funnel and 5CF paper to separate the IFp liquid fP, and quantify the Sl contained therein.

However, in reality, Si is taken into the bulb-shaped filter paper, and no matter how much you wash it, when examined with fluorescent X-rays, St is detected in the bulb on the filter paper and washed out into the furnace liquid. There wasn't. This is the same whether it is washed with warm hydrochloric acid or HF, and 83 remains in the valve.

ai) Patterned funnel and polyethylene funnel and 5C
Method using F paper As a countermeasure for solving the above-mentioned drawback (1), suction filtration using a patterned funnel with a filter paper portion of 8 mm diameter was tested.

After filtration of the sample solution, while washing the 5i02° precipitate and 8φ 50 filter paper, place them in a polyethylene beaker and add c.
After dissolving with a constant amount of oncHF' (2 mA), it was filtered through a boiling ethylene funnel. After washing, Si was not detected even when the filter paper, including the 8φ filter paper, was examined using fluorescent X-rays.

However, with this method, when putting 5102 into a polyethylene beaker, the SiO□ adhering to the inner wall of the patterned funnel must be washed out using a polymer, so there is a risk that it may not be washed out completely and errors may occur. Since a large amount of washing water is used at that time, even if you try to dissolve it with HF afterwards, the HF concentration will be too low! +, 5i02 cannot be completely dissolved.

Shouting Teflon filter and 5C for liquid chromatography
Method using P paper As a method for improving the above-mentioned (11), suction filtration using a Teflon filter for liquid chromatography as shown in FIG. 3 was tested. Normally, Teflon filters for liquid chromatography are filters that push the solution from a syringe into the filter, and have excellent chemical and solvent resistance, but this time we have processed it to have suction filtration power. I used it. Filter (7 has a size of 13Iwφ).

This one doesn't have a funnel part, so I made it myself by processing a Teflon rod. Since the filter itself is made of Teflon, the filtration speed is slow, so 5CF paper was processed to 13φ and replaced. First, the sample solution was filtered through the liquid chromatography filter shown in FIG. 3. Thereafter, the filter is disassembled and the precipitate, P paper, funnel, and part of the filter are placed in a polyethylene beaker. and HF(1+9)
After dissolving the precipitate at a constant rate (20 ml), take out the P paper, funnel, and part of the filter while washing them. At this time, since suspended matter that does not dissolve in HF still remains, the HF solution is filtered again using a liquid chromatography filter.

When the floating matter taken on P paper was examined using fluorescent X-rays, only Ti was detected.

An advantage of using this filter is that there is no way that the funnel and part of the filter can be subjected to HF treatment at the same time. Furthermore, since the filter 7 has a small diameter and Teflon itself has water repellency, it is a great advantage that cleaning after filtration can be done with a small amount of water. Moreover, it has the advantage that it can be used again when removing suspended Ti from the HF solution.

With this method, all the 5io2 precipitates in the sample solution are H
It is now possible to collect it in the F solution.

Therefore, we actually tested the recovery rate of 5in2 using a silicic anhydride reagent. As a result, as shown in Table 1, a very good recovery of St was obtained.

Theoretical value of Si recovery rate when used: Weigh out the reagent silicic anhydride, directly dissolve it in HF in a poly beaker, and then measure with ICP Using a liquid chromatography filter: Use the reagent silicic anhydride in the same amount as the theoretical value. Add 120 ml of weighed LAHC, filter through a liquid chromatography filter, filter the precipitate, perform HF treatment, filter again and measure by ICP. The method described in the book involves separating the precipitates, P paper, a-t, and a part of the filter into a polyethylene beaker, dissolving them in HF, and then reapplying them. All of the 5io2 precipitates in the sample solution can be recovered in the HF solution. Since very good results were obtained, we decided to adopt this method.Next, we investigated quantitative analysis methods.

(4) Quantitative analysis method A. Quantitative analysis of St in HCL solution P solution obtained by filtering a sample dissolved in HCL in a pressurized crucible was diluted with water for 10 minutes.
Keep it constant at 0 ml.

Sl in the solution was quantified by a calibration curve method using ICP.

Calibration curve for medium Si At 1000 ppm standard solution for atomic absorption was diluted to 1/1 (100 pprn) and Na2CO30,4
Make into N solution. From there, Si is separated, diluted with water, and S
A view line was created for six samples with variations of 05, 1.0, and 1.5 PPm. At that time, the analysis wavelength of ICP is 251
It is 6&. As a result, as shown in Figure 4, the luminescence intensity and
If C is Si# degree and R is linear correlation coefficient, I=459
A straight line of C+40.33 R Tsukasa and 999999 was obtained.

Effect of beating reagent Three samples were prepared in which the amount of HCL added was changed to 10, 20, and 30 mt while keeping Si711 degrees constant at IPI)m, and the effect on the recovery rate of Si was investigated.

The results are shown in Table 2 and Figure 5.

As the amount added increases, the recovery rate tends to decrease.

This is because when sucking a sample into the ICP nebulizer, the suction port is narrow, and as the viscosity of the solution increases, the amount of suction decreases. Therefore, it is necessary to match the acid concentration of the calibration curve sample to the acid concentration of the actual sample solution.

Table 2 Influence of HCL θ1p Influence of Coexisting Elements As a result of keeping the Si concentration constant and changing the measurement of Ti and Ba to investigate the difference in the recovery rate of Si, it was found that the addition of Ba had no effect on Sl. On the other hand, depending on the addition of Ti, there was a large difference in the recovery rate.The influence of Ti was investigated in detail.

(7) About the Ti calibration curve First, to measure the concentration of Ti contained in the actual sample solution, in order to use the same decomposition reagent, Ti was replaced with HCl.
must be dissolved in This problem was solved because about 2 tons of Ti could be dissolved in 20 ml of HCL by heating at 150° C. for 1 hour using a pressure crucible. Ti was fractionated from this and the concentration was 736,883,10
Four samples of 30.1177 pprn were prepared and ICP
The measurement was performed at an analysis wavelength of 6685A. In addition, each sample is
1 ml of HCL 2 was added per 100 ml to give the same acid concentration as the actual sample solution.

As a result, as shown in Figure 6, < r = 0 as the calibration curve for Tl.
．． A straight line of 889c+34J R=[+,999 was obtained.

We also investigated the effects of Si and h on the Ti recovery vehicle, and found that they had no effect at all when measuring at a wavelength of 3685X. T of
When the i concentration is determined, it is 925 ppm of Ti.

(I) Effect of addition of Ti Since the actual concentration of Ti in the sample solution was found to be 925 ppm, the concentration was varied before and after that and the effect on Si was investigated.

The results are shown in Table 3 and FIG.

Keeping the Si concentration constant lppm, Ti0 degree 736.8
83. Six samples with 1030 ppnn were prepared and I
In CP, the difference in Si recovery rate was measured in a straight line relationship. In other words, as the degree of TlG increases, the measured value of Si also increases accordingly.

Table m3 Regarding the creation of the correction formula for the influence of Ti, the formula (1) for the relationship between fcS, T, and A obtained in (a) can be obtained from formula (2). When the actual measured values are corrected, very good results are obtained as shown in Table 4 and FIG. 7 below.

Table 4 Correction calculation (for correction of the influence of Ti) According to the actual sample and concentration of HCl (HCL20mL/1
The 81 and Ti concentrations in the sample were measured using the calibration curve prepared by combining the 81 and 81 degrees (St and Tit), and the above-mentioned measured 8i degrees were calculated based on the true St concentration and the above correction formula (
2) Substitute into equation 2 and find: This is the value when 'lODmt is constant, so it can be determined by converting it into weight.

For quantitative analysis of 8i in H, HF solution, SiO2 precipitate was dissolved in HF in IF bath solution, as is I 'CP''
'C'C'C measurement and measurement equipment may be damaged.
Measurement is performed after adding 3BO3 to mask HF in the form of B F4 . At this time, I(s
As for the amount of BOa, 3f is sufficient according to past literature.

After adding HmBOs, make up to 100 ml with water in a 10-neck mt volumetric flask and transfer to a polyethylene sample bottle. This process must be done quickly or else the HF may melt the glass, so care must be taken. According to the literature, about 30 minutes is the limit for contact with glass.

St in this (HF+H, BO3) solution was measured by ICP using a calibration curve method.

Calibration curve for medium St. 8i was taken from a standard solution of Si 100 ppm, diluted with water, and the four concentrations of 5, 10, 15, and 20 Ppm were measured to create a calibration curve as shown in FIG. As a result, a straight line of I = '52.38C + 16 R = 0.9999 was obtained.
The difference in the recovery rate of St when O was added was determined. The results are shown below in Table 5.6 and Figure 9.10.

Table 5 Influence of H, BO, Table 6 Influence of HF a From this, it was found that as the amount of both HF*H3BOs added increases, the recovery tends to increase. Therefore, to create an actual calibration curve, HF and HsB
It is necessary to match the O3 concentration to the sample.

01+) Influence of Coexisting Elements As mentioned above, since there was no influence of Ba, only the influence of Ti was investigated. First, the Ti concentration in the (HF + HsB Oa) sample solution was measured, and it was determined whether there was a difference in the recovery amount of 81 in the vicinity of the Tia degree.

(7) Samples with Ti concentrations of 32, 64, 96, and 128 ppm were prepared for the Ti calibration curve. Ono f(F 2m'-/I DO1
tHsB9g, 3ri00m7 is shouting. From this I
Using CP, measurement was performed at an analytical wavelength of 6685, and a calibration curve of < Ti was created as shown in FIG. 11.
A straight line □ with 92C-14R=0.999 was obtained. The Ti concentration of the actual (HF + H3B Os ) solution was determined to be 70 pPm.

(b) Regarding the influence of Ti, the Si concentration is kept constant at 10 ppm, and the Ti concentration is 74°8.
Five samples with different values of 8 and 105 ppm were made, and T
Table 7 and FIG. 12 show the results of the differences in the Si recovery system due to the addition of i.

From this, it can be said that the difference is within the allowable range & (within ±2%), so it was determined that there was no influence of Ti. This is because the a reaction force S of the weight Ti is thicker than the amount of SiO.

Table 7 Influence of T1 (1) Results of the constant concentration of Si in HF solution Therefore, the actual sample and BF (2m/, /Ioorrlt) and HsBO
3"/100rnL) 810 degrees in the actual sample solution was measured from the SL calibration curve combining a degrees, which is 100 degrees.
Since this is the value when rnL is constant, it can be determined by converting it into weight.

The 81 content in BaTiOs is the H
The Si content in the Ct solution and the HF solution described in B above (
It can be determined by adding the quantitative results of D St, but it is necessary to create new calibration curves for Si and Ti each time.

To summarize the features of the present invention, (1) After dissolving the sample, the total amount of silicon contained in the sample is determined by separately quantifying the silicon contained in both the precipitate and the furnace liquid.

(2) By using a Teflon filter that is resistant to attack by HF, the silicon decomposition reagent, the silicon recovery rate and accuracy are improved.

(3) Sample solution and calibration curve standard solutions of hydrochloric acid, HF, and HsB
4) In order to remove the property of HF that corrodes glass, %B Q3 was added to mask it.

(5) In order to remove the influence of titanium, a correction formula is created and the actual measured value of silicon is corrected to find the true value and reduce the error.

(6) In order to use the same decomposition reagent as the sample for the titanium calibration curve, titanium was dissolved in hydrochloric acid using a pressurized crucible.

(7) Since the ICP is used and the calibration curve method is used to perform the footrest directly, accurate values can be obtained in a short time.

Ba by plasma emission spectroscopy (CICP) according to the invention
The method for quantitative analysis of Si in TiO3 is (1) BaTiO
Silicon in 3 can be quickly and accurately quantitatively analyzed. This allows for product quality control, process control, and establishment of manufacturing conditions.

(2) Products can be manufactured stably with good reproducibility.

(3) Differences in properties caused by subtle differences in silicon content can be clarified.

It is useful and has the following effects, Next, an example will be described.

Example (1) A 0.5 t sample of barium titanate was weighed out, 20 ml of hydrochloric acid was added thereto, and the sample was dissolved in a pressurized crucible shown in FIG. 2. At that time, heat for 1 hour and stir for 30 minutes for a total of 6 hours.

Also, during stirring, the stirring bar 6 inside the crucible is
Rotate and stir. (3: (2) Dissolution Apprentice) Perform suction filtration using a liquid filter shown in Figure 3. Add a 100 mt volumetric flame flask cleaning solution to the p liquid, and make it constant at 100 m with water. Using ICP, the calibration curve of Figure 4 SL and the calibration curve of Figure 6 T1
(4) Determine the degree of i concentration and the Ti concentration, and use the correction formula that corrects the influence of T1 on 81 to determine the St concentration of -12X.

That is, the actual sample and the concentration of Hct (HCL20mL/10
When measuring 81 and Ti 6 degrees in the sample using the calibration curve created by combining o, , , >, 81: 0.41 ppm, Ti: 925 ppm
If m is calculated by substituting this value into the above correction (2), then = 0.
28 Cppm: This is the value when 100 ml is constant, so when expressed in weight, it is 0-028 mr.

) The precipitate obtained using a liquid chromatography filter is first placed in a polyethylene beaker together with the filter, and 5i02 is dissolved with 20 m/= of HF (1+9). After that, thoroughly wash the filter and filter paper and remove the contents of the beaker.

1 1-Since a small amount of suspended Ti is used on the IF solution, this solution is filtered again using a liquid chromatography filter.
do. The filtrate was taken into a polyethylene beaker and added to H2B.
After adding O33f and dissolving it, transfer it to a 100 ml volumetric flask, keep the volume constant at 100 m, and transfer it again to a polyethylene sample bottle. At this time, add (HF) to the volumetric flask.
+ HaB Os
i is measured using IC'P, and the calibration curve shown in Figure 8 is used.
) When Si2 degree is measured, St: 11.18 ppm
Also, since these are values when the current is constant at 100 mA, it becomes 1.118 rnf when expressed in terms of one weight.

(5) Therefore, the amount of sii in barium titanate 0.52
According to (4) above, St 1.118 in the 9HF solution
M? include.

Therefore, BaTi010.5? The amount of sl contained in it is 0.028+1.118-1.146nnfte,
This becomes MB%TO, 229wt%.

In addition, the measurement wavelength of ICP Si;2516^T1:36
85A Furthermore, the following analysis equipment was used.

Inductively coupled high-frequency argon plasma emission spectrometer (I
CP): ICAP-50 manufactured by Nippon Jarrell Ash Co., Ltd.
0 Fluorescence X-ray analyzer: Manufactured by Rigaku Denki Kogyo Co., Ltd.

[Brief explanation of the drawing]

Figure 1 is a flowchart showing the analysis method for BatiO3 or ceramics, Figure 2 is a schematic diagram of a pressurized crucible, and Figure 3 is a flow chart showing the analysis method for BatiO3 or ceramics.
The figure is a schematic diagram of a filter for liquid chromatography, Figure 4 is a Si calibration curve showing the relationship between Si concentration and luminescence intensity, and Figure 5 is a graph showing the relationship between the amount of decomposition reagent HCJa added and Si recovery rate. Figure 6 is a Ti calibration curve showing the relationship between Ti concentration and luminescence intensity, Figure 7 is a correction graph showing the relationship between 11m degrees and Si recovery rate, and Figure 8 is a Ti calibration curve showing the relationship between Ti concentration and luminescence intensity.
St! shows the relationship between concentration and luminescence intensity. Fig. 9 is a graph showing the relationship between the amount of HsBO3 added and the amount of Si recovered.
Fig. 10 is a graph showing the relationship between f(F addition amount and Si recovery rate), Fig. 11 is a Ti analysis diagram showing the relationship between T1 degree in HF melt rice and luminescence intensity, and Fig. 12 is a graph showing the relationship between f(F addition amount and Si recovery rate). 13 is an analysis flowchart of an example of the present invention. 1... Container made of stainless steel, 2... Container made of Teflon,
6... Pressurized crucible, 4... Teflon lid, 5...
Screw, 6... Stirrer, 7... Filter. Agent Patent Attorney Sanro Kimura 1 @ C: St: Mouth (ppm) Figure 5) 1ci Ruri Ado [ml]

Claims (4)

[Claims] (1) Add concentrated hydrochloric acid to the sample, heat and dissolve in a pressurized crucible, cool and filter with suction through a synthetic resin pouch or filter to separate into furnace liquid and precipitate, The silicon content in the furnace liquid is measured by plasma emission spectrometry, while the precipitate is placed together with the filter in a polyethylene peaker, a hydrogen fluoride solution is added, and the filter and filter paper are washed; The obtained hydrogen fluoride solution was filtered through the filter, separated into filter paper residue and P liquid, and H3B was added to the obtained furnace liquid.
After adding O3 and dissolving it, the resulting hydrogen fluoride solution was subjected to plasma emission spectrometry to measure the silicon content.
A quantitative analysis method for silicon in barium titanate using plasma emission spectroscopy, characterized in that the silicon content in the liquid is determined by adding the silicon content in the hydrogen fluoride solution. (2) Test subjects 0,5? 20 ml of concentrated hydrochloric acid was added to the mixture, heated in a pressure crucible for 1 hour, and stirred for 60 minutes, for a total of 6
Dissolve by heating at 150°C for an hour, and after cooling, suction filtrate with a Teflon filter for liquid chromatography, separate into P liquid and precipitate, collect 100 mt of the furnace liquid, and use it for plasma emission spectrometry analysis. Ti
In order to eliminate the influence of
Add a hydrogen fluoride solution of 1 volume of HF and 9 volumes of water,
Dissolve, wash the filter and filter paper, filter the obtained hydrogen fluoride solution with the filter, separate the p paper residue and filtrate KF, add 3t of HiBOi to the obtained p liquid,
The hydrogen fluoride solution obtained after dissolution was made up to 100 ml, and the silicon content of the obtained hydrogen fluoride solution was measured by plasma emission spectrometry, and the silicon content in the filtrate and the hydrogen fluoride solution were measured. 2. The analysis method according to claim 1, wherein the analysis method is determined by adding the silicon content in the silicon content. (3) In plasma emission spectrometry, the calibration curve and the acid concentration of HF-H3BO3-HcL in the sample solution to be measured are matched.
Analytical method described in section. (4) In plasma emission spectroscopy, when determining the Si calibration curve and the calibration curve of coexisting Ti, the analysis wavelength is set to Si. 2516A''Tl: 368580.