JPS61178651A - Method for solidifying powdery specimen for fluorescent x-ray analysis - Google Patents

Abstract

PURPOSE:To easily obtain a solidified body for fluorescent analysis prevented from the peeling- off and scattering of a powdery specimen and capable of being preserved for a long period of time after molding, by uniformly mixing the powdery specimen and a predetermined ratio of a thermosetting resin, and molding and solidifying the resulting mixture into a required shape under heating and pressure. CONSTITUTION:The powdery specimen such as slag generated in a steel melting process is finely pulverized to reduce the particle size thereof to 100 mesh or less and 4pts.wt. or less of the resulting powdery specimen is uniformly mixed with 1pt.wt. of a thermosetting resin such as a phenol resin not containing an analytical objective component or containing the same only in a minute amount capable of being subjected to definite correction and the obtained mixture is pressurized under heating by a mold 12 and a die 16 to obtain a cylindrical solid specimen with a diameter of 30-30mm and a height of about 20-30mm. If the specimen is a minute amount, the mixture 10 of the powdery specimen and the resin in the aforementioned ratio is received in the bottom part of the mold 16 and only the thermosetting resin 14 is supplied thereon and the whole is molded to obtain a cylindrical solidified body 18 having the aforementioned dimension, which consists of a thin layered specimen part A and the base part B only comprising the thermosetting resin, and easy to handle. By this method, a solidified body for fluorescent analysis prevented from the scattering of the powdery specimen in an analytical chamber is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for solidifying a non-standard powder sample in order to facilitate X-ray fluorescence analysis.

Conventional technology Chemical analysis methods have traditionally been widely adopted for qualitative analysis and other quantitative analysis of elements contained in various samples.
In particular, when the target of analysis is fluorine (F) or higher elements, fluorescent X-ray analysis is preferably used. That is, each atom constituting a substance has a unique shell electron level, and when this substance is irradiated with X-rays, characteristic X-rays (fluorescent X-rays) having properties unique to the atoms are excited from the substance. Fluorescent X-ray analysis utilizes the above phenomenon, and the characteristic X-rays excited from a substance are passed through a spectroscopic crystal to select the wavelength, and the peak tops in the X-ray spectrum are read and analyzed from standard samples. The types and amounts of atoms present in a substance are analyzed by comparing them with the obtained calibration curve.

This fluorescent X-ray analysis method is used in a wide range of fields as a quantitative analysis method for process analysis and other purposes for harmful species, regarding samples in various states such as solid samples, liquid samples, and powder samples. By the way, in order to obtain good results by subjecting various samples to the fluorescent X-ray analysis, the samples for analysis are required to have the following conditions. (a) The surface composition of the sample to be analyzed is representative of the substance in question.

(b) It does not undergo deformation or other alteration and has a flat surface.

(C) The constituent substances of the sample do not scatter or volatilize.

(d) If a thick film is provided to maintain the shape of the analysis surface or to prevent scattering or volatilization, it must be applied to an extent that does not attenuate negative X-rays or secondary X-rays.

(e) Mechanically strong and free from damage during handling.

Solid samples are the most suitable for these conditions, but in order to perform fluorescent Some kind of ingenuity is needed to bring the situation closer to that of . For example, in the case of a liquid sample, a method is to cover the opening of a container filled with the liquid under tension with Mylar, irradiate the sample surface with primary X-rays that pass through the Mylar, and extract and analyze the secondary X-rays. It has been implemented. Regarding powder samples, the briquette method and glass bead method are generally used to fix the highly fluid state.

Problems to be Solved by the Invention The briquetting method is a method in which the powder is further finely pulverized to the required particle size range, and then pressure-molded using a hydraulic press to form a solid sample (when the sample is small, (Add a filler such as cellulone powder). However, this method has the disadvantage that the powders peel off or otherwise disintegrate and scatter from the surface of the solidified sample because the bond between the powders is not strong. In particular, in fluorescent X-ray analysis, since a vacuum chamber is used as an analysis device, powder tends to scatter in this chamber. Moreover, it contaminates the hands of the analysis worker and also adheres to other samples, causing analysis errors when analyzing samples with different compositions.

In addition, in the glass bead method, a finely pulverized powder sample is mixed with a flux mainly composed of lithium borate, and approximately 10%
This method involves melting at a temperature of 00'C for about 10 minutes, annealing, and cooling to obtain a glass bead-shaped solid sample. This method does not cause scattering of the powder sample as seen in the briquette method, and is widely used. However, if metal powder is mixed into the powder sample, the metal component will react with and attack the platinum plate during melting of the sample, making the expensive platinum plate unusable. There are restrictions on the powder samples to which this method can be applied.

Purpose of the Invention The present invention has been proposed in order to suitably solve the problems inherent in the conventional methods described above. It is an object of the present invention to provide a novel method for solidifying a powder sample for fluorescent X-ray analysis, which allows solidification of a powder sample for fluorescent X-ray analysis, and in which the powders are closely bonded to each other so that the powders do not easily peel off and scatter.

Means for Solving the Problems In order to achieve the above-mentioned object, the solid state of the powder sample for fluorescent X-ray analysis according to the present invention, i. It is characterized by uniformly mixing at a predetermined ratio, heating the resulting mixture, shaping it into a desired shape, and solidifying it.

EXAMPLES Next, the method according to the present invention will be explained with reference to preferred examples. That is, the present invention relates to a method of solidifying the powder by mixing a finely pulverized powder sample and a thermosetting resin in an appropriate ratio and thermoforming the mixture.

This powder sample can be used as is if it has been sufficiently pulverized to fall within the specified particle size range, but if the particle size is coarse or uneven, it must be pulverized to the required particle size. do. To finely pulverize this powder, it is sufficient to use equipment such as a vibrating mill, parallel mill, jet mill, etc., as used in the conventional briquette method and glass bead method, and preferably the particle size is about 100 mesh. Finely grind to the following size. The thermosetting resin mixed with this is a general term for resins that undergo chemical reactions under the action of heat, catalysts, ultraviolet rays, etc. and become almost insoluble and infusible in the final state, including phenolic resins, urea resins, and epoxy resins. Any material such as resin may be used. However, it is of course necessary that the component to be analyzed is not contained in the thermosetting resin. Note that even if the component to be analyzed is the oldest, there is no problem as long as the amount is always constant and can be corrected.

The powder sample and the thermosetting resin must be mixed as uniformly as possible, and if the mixing and agitation is insufficient, accurate analytical results cannot be obtained. Therefore, it is recommended that the particle size of the thermosetting resin be as close to the particle size of the powder sample as possible.

Furthermore, the mixing ratio of the powder sample and thermosetting resin can be freely selected depending on the purpose of analysis, but as the mixing ratio of the thermosetting resin increases, the dilution rate of the powder sample becomes relatively large. It is necessary to keep in mind that Therefore, when quantitatively analyzing trace amounts of components contained in a powder sample, it is preferable to reduce the amount of thermosetting resin and increase the proportion of the powder sample. However, if the proportion of the powder sample is increased too much, the bonding strength that solidifies the sample will decrease, and the powder sample will peel off and scatter from the surface of the molded solidified object, similar to the briquetting method described above. Therefore, there is a limit to the increase in the proportion of such a powder sample.

Experimental Example A test was conducted in which slag (mine slag and steel slag) produced during the steel melting process was pulverized to 100 mesh or less, and mixed with phenolic resin in various proportions and heated to form the mixture. As a result, it was found that a weight mixing ratio of less than 4 parts of the powder sample to 1 part of the thermosetting resin was the limit for effectively preventing the powder sample from peeling off and scattering. The dimensions of the molded sample may be such that it can secure the necessary flat irradiation area in the analyzer for fluorescent X-ray analysis and is easy to handle.
Form into a cylindrical shape with a height of about 20 to 30 mm.

The powder sample solidified in this manner does not peel or scatter as seen in the briquette method, and once molded, it can be stored for a long time and can be used repeatedly, especially as a standard sample. Further, the only equipment required is a pressure molding machine, and a solidified sample can be obtained easily and in a short time.

In addition, when the amount of the powder sample is small, in the briquette method, if the total amount is less than the amount that makes it impossible to obtain a briquette-like sample, it is not possible to pressurize it and make it into a solidified sample. Also, even with the glass bead method, repeats cannot be created unless the dilution rate is increased. Moreover, if the dilution rate is increased, it becomes unsuitable for analysis of trace components. In such a case, according to the present invention, even a small amount of powder can be subjected to fluorescent X-ray analysis in the following manner. That is, the mixing ratio of the powder sample and the thermosetting resin is selected appropriately depending on the purpose, and the total amount after mixing is determined in accordance with the amount of the powder sample. As shown in FIG. 1, a mixture 10 of a powder sample and a thermosetting resin is first uniformly inserted into the bottom of a mold 12 for thermoforming. On this mixed layer 10, the thermosetting resin alone 14 is placed.
is further placed and heated and formed by the die 16.

The thus obtained solidified sample 18 shown in FIG. It is composed of a double layer with a base part B made of a hardened thermosetting resin to compensate for the sample part A, which is difficult to handle due to its layered structure, making it easy to handle even a small amount of powder sample. In this example, the same thermosetting resin as the thermosetting resin mixed in sample portion A was used as the base B, but this was different from mold 12.
For the convenience of simultaneous molding, the base may be formed of a subcomponent and have an appropriate shape.

Effects of the Invention As explained in detail above, according to the method for solidifying a powder sample for fluorescent X-ray analysis according to the present invention, a powder sample that does not have a regular shape can be easily transformed into a form that is easy to perform fluorescent X-ray analysis. Since it can be solidified and the powders are closely bonded to each other via the resin, the powder sample does not easily peel off from the solidified material, which is preferable.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of integrally molding a base to a powder sample obtained by the method of solidifying a powder sample for fluorescence xm analysis according to the present invention, and FIG. FIG. 3 is a schematic perspective view of a powder sample placed on a base. FloG, 1 FIG, 2

Claims (4)

[Claims] (1) A powder sample to be subjected to fluorescent X-ray analysis and a thermosetting resin are uniformly mixed at a predetermined ratio, and the resulting mixture is heated and formed into a desired shape to solidify it. A method for solidifying a powder sample for fluorescent X-ray analysis. (2) The method for solidifying a powder sample for fluorescent X-ray analysis according to claim 1, wherein the weight mixing ratio of the powder sample to the thermosetting resin 1 is set to 4 or less. (3) The method for solidifying a powder sample for fluorescent X-ray analysis according to claim 1, wherein the powder sample is further finely pulverized if necessary. (4) A powder sample for fluorescent X-ray analysis obtained by heating and solidifying a mixture of a powder sample and a thermosetting resin is bonded to a base having a desired shape. A method for solidifying a powder sample for fluorescent X-ray analysis.