JPH03218445A - Analysis of glass composition - Google Patents

Abstract

PURPOSE:To rapidly carry out composition analysis with high precision by thermally decomposing a glass consisting essentially of lead oxide and boron trioxide with an aq. sodium hydroxide soln., neutralizing the sample soln. thus obtained and subjecting the neutralized soln. to plasma emission spectrochemical analysis. CONSTITUTION:The glass is completely dissolved in an aq. sodium hydroxide soln., the soln. sample contg. Pb and B is neutralized and stabilized, and the soln. amt., dilution, etc., are adjusted to prepare a sample. The sample is introduced into plasma from the sample feed part of a plasma quantometer, and a luminous beam is radiated from the dissolved element. Measurement is simultaneously carried out. The intensity of the luminous beam is proportional to the concn. in the sample soln. Consequently, plasma emission spectrochemical analysis is stably carried out with high precision.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for analyzing the composition of glass, and in particular to a rapid and highly accurate method for analyzing glass whose main components are lead oxide and boron trioxide. [Prior art] Glass is generally made by mixing a specified amount of natural raw materials such as silica sand, feldspar, limestone, and dolomite according to a target composition, melting the mixture in a crucible, etc., forming it, and then slowly cooling it to solidify it. be. Typical glasses include soda lime glass and borosilicate glass. The composition of glass varies over a wide range depending on its use, and its shape varies from plate-like to powder-like. For example, powdered glass is also used as a coating material, and as an arrester coating material, glass that satisfies the target characteristic of discharge resistance is required. The material composition is based on lead oxide (PbO) and boron trioxide (B*Os), and additives are added to improve the material properties. The composition of glass varies depending on its use, and in order to ensure the required physical properties, it is important to strictly control each composition, and there is a need for a method to quickly and accurately quantify the composition of glass constituent materials. ing. The official analytical method for glass includes the analytical method for soda-lime glass (JI
SR 3101), Analytical method of borosilicate glass (JI
Sl? 3105). Preparation of analytical samples uses various instruments and reagents, and differs depending on the component to be quantified. For quantitative determination of SxOg+ Btus, etc., sodium carbonate (
NapCO, ) is melted, and other components are often subjected to hydronic acid (HP) decomposition. In addition, to detect each component, each element is subjected to various pretreatments and then quantitatively determined by applying gravimetric method, spectrophotometric method, and titration method and atomic absorption method.

[Problem to be solved by the invention]

However, the conventional official analysis method for glass (JISR
3101. When the sample preparation method of JIS R 3105) is applied to this sample, pboB20, glass, it is not possible to completely convert the sample into a solution, so separation operations and re-decomposition are necessary, making analysis operations complicated and time-consuming. Lacking sex.
In addition, when applying elemental detection methods, sample solutions with high salt concentrations are affected by coexisting components and additional pretreatment is required, making them unsuitable as glass composition analysis methods. This invention has been made in view of the above points, and its purpose is to
・Our objective is to provide a rapid and highly accurate method for analyzing the composition of PbO-BJs-based glass by improving the pretreatment method for B,0-based glass samples. [Means for Solving the Problem] According to the present invention, the above-mentioned object has a first step, a second step, and a third step, and the first step contains lead oxide and boron trioxide as main components. The second step is to neutralize the sample liquid obtained in the above step, and the third step is to subject the neutralized sample liquid to plasma. This is achieved by performing analysis using emission spectroscopy.

PbO and B80 are dissolved by NaOH solution. The melt is strongly alkaline and is neutralized with nitric acid for long-term stability and to prevent contamination from equipment. Nitric acid is effective in dissolving dissolved lead as nitrate without precipitating it. PBO is an amphoteric oxide and dissolves in both sodium hydroxide and nitric acid to form a salt. PbO+ 2 NaOB+3 }1gO=Naz (P
b(OH)4(OHx)g)... (sodium zincate)PbO+2HNO, -Pb(NOs)i+
}ltO ------1 lead nitrate) B. O. is obtained by dehydrating boric acid and is expressed by the following formula. 2 HsBOs - thos + 3 HtO solubility is 15.7g/100μL (100℃), and in water it becomes metaboric acid (HBOg), then orthoboric acid (
HsBOs) and dissolves. It also dissolves in acids and alkalis.

The glass is made into a complete solution by a decomposition method using a sodium hydroxide solution, and the solution sample containing Pb and B is further neutralized and stabilized, after which the liquid volume, dilution, etc. are adjusted as appropriate, and the preparation of the analysis sample is completed. ．． Next, it is subjected to plasma emission spectroscopic analysis. Analytical needle sample liquid supply section (nebulizer)
is guided into the plasma, and at this time, the dissolved elements emit luminescent rays. Measurements are performed simultaneously, and the intensity of the emission line is proportional to the concentration in the sample solution. Standard samples are prepared using standard solutions of each element, and sodium hydroxide and nitric acid are added. A calibration curve is created from the standard sample whose matrix has been matched in this way. The intensity of the emission line is expressed as ■, the element concentration (weight% or ppm
) is tested with W, a, and b as constants.f&ll is expressed by the following fl) formula. W=al+b・1・−・・−・・・・・・
-(l) The absolute amounts of Pb and B are determined from the element concentration in the sample liquid and the amount of sample liquid.The amounts of PbO and BzOs in the glass are converted from the above element amounts to the oxide amounts, and the amounts of PbO and BzOs in the glass used for decomposition are The composition can be determined from the relationship with the sample amount.

[Effect]

Glasses based on PbO and B,03 are quickly, easily and completely dissolved using sodium hydroxide solution. This enables stable and highly accurate analysis using plasma emission spectroscopy. [Example] Next, an example of this invention will be explained based on the drawings. 1st
The figure is a flowchart showing the procedure for preparing an analysis sample according to an example of the present invention. The analysis sample is mainly glass consisting of pbo and B,0, and also contains ceramic materials. When analyzing the composition of materials whose constituent elements are unknown or whose impurities are unknown, qualitative analysis is usually performed in advance to clarify the presence of inorganic elements before quantification is considered. The shape of the glass is a plate. There are powder forms, but here we will use the powder form. The sample is
In order to remove the adsorbed moisture, it is dried at 105°C for 2 hours, left to cool in a desiccator, and then a predetermined amount is weighed.
The amount of sample to be analyzed is often on the order of several hundred mg. Here, 500a+g was used. Next, the capacity is 200L
PbO. B,0
3rd grade is decomposed. In this case, unlike the alkaline fusion method using sodium carbonate, etc., the alkali decomposition method described above was used, so a normal hard glass beaker can be used as is, making the analytical operation easier. After cooling, a portion of phenolphthalene indicator is added, neutralized with nitric acid (1:1), and an excess of 5 mL is added to stabilize the sample solution. Neutralization with nitric acid is effective in stabilizing the sample solution without producing reaction products such as precipitates. It is then warmed to dissolve the soluble salts, and after cooling, it is filtered if there are any insolubles. The volume of the filtrate is adjusted to complete the preparation of the analysis sample solution, which is then measured and analyzed. This sample preparation facilitates the decomposition operation of pbo, BzOs-based glasses, eliminating the need for conventional operations and allowing a complete solution to be obtained. Next, let's talk about the calibration curve. The plasma emission spectrometer has a sample introduction section (nebulizer).
It consists of a light source section, a spectroscopic section, and a photometry section, and the light source section uses high-temperature argon plasma with an excitation temperature of 6000 to 8000 K. The emitted light is separated using a spectrometer, and photoelectric detection is generally performed using a photomultiplier tube. Solutionized pbo and 8
The intensity of the emission line of each element is measured from a glass sample solution consisting mainly of 80. The standard sample is prepared in advance from a standard solution of known concentration, and matrix matched by adding sodium hydroxide and nitric acid.

A calibration curve is created using the least squares method from the relationship between the intensity and concentration of the emission line for each source under the following measurement conditions. (Measurement conditions) ■ Element and wavelength (Pb 220.353nm, B2
49.773 rv) ■ Integration time: 1 second ■ Number of integration: 3 times ■ RF power: 1.36 KW ■ Photometric height: 11.9 m (above the work coil) Fig. 2 is a calibration curve according to an embodiment of the present invention.

Pb. 12 shows an example of B, ~500
The quantitative range of mg/L is shown. In both cases, calibration curves with good linearity were obtained. The following formula can be obtained as an experimental formula. (Liquid concentration mg/
L) Pb (1 g/L) = 1.68xlO-' I-1
．． 13 Correlation coefficient 0.999 −{2冫B(sog/
L)=1.23xlO-” I-0.83 correlation coefficient
0.999・1(3) It can be seen that the correlation coefficient between the luminescence intensity and the concentration in the liquid is 0.999, which is good. Next, the sample preparation method shown in FIG. 1 was applied to a glass sample containing pbo and 8,0, and the analytical accuracy was examined repeatedly using the above calibration curve. Table 1 shows the results. Here, using 0.5 g of a powdered glass sample, the concentrations of Pb and B in a solution made up to 1 L are shown.

Table 1 iooo It can be seen that the repeat analysis accuracy is good, with a coefficient of variation of 0.8% or less. Furthermore, the average value of the analysis values is multiplied by a coefficient and converted to the amount of oxides. The conversion coefficient of pb to pbo (atomic weight ratio of PbO/Pb) is 1.0772,
B of B! Conversion factor to 0 (B!03/B atomic weight ratio)
3.220 is used. In this case, 0.5012 g of powdered glass is used to decompose the analysis sample, and from the analysis values in Table 1, (PbO + BO0,) is 0.4994.
g, and the recovery rate was high at 99.6%, indicating high accuracy. The time required for analysis according to the present invention, including sample preparation and measurement, is less than one hour, which is faster than conventional alkali melting and gravimetric methods. This is faster than the approximately 8 hours it takes to analyze each element by applying spectrophotometry. [Effects of the Invention] According to the present invention, there are a first step, a second step, and a third step. The second step is a step of neutralizing the sample liquid obtained in the above step, and the third step is a step of analyzing the neutralized sample liquid by plasma emission spectroscopy. As a result, the glass can be quickly, easily and completely turned into a solution, which makes stable and highly accurate plasma emission spectroscopy possible. Overall, it is possible to quickly and accurately analyze the composition of glass containing PbO and 8803 as its main components. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a procedure for preparing an analytical sample according to an embodiment of the present invention, and FIG. 2 is a diagram showing a calibration curve according to an embodiment of the present invention. 11: Pb calibration curve, 12: B calibration curve. Yu 1 Zuno Notification (“l/ノ) Figure 2

Claims (1)

[Claims] 1) It has a first step, a second step, and a third step, and the first
The step is a step of thermally decomposing glass containing lead oxide and boron trioxide as main components using an aqueous sodium hydroxide solution, the second step is a step of neutralizing the sample liquid obtained in the above step, A method for analyzing the composition of glass, characterized in that the third step is a step of analyzing the neutralized sample liquid by plasma emission spectroscopy.