JP2853580B2 - Dissolution treatment method for chemical analysis samples - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dissolving a sample for chemical analysis of a solid sample having low evaporation and volatility, and can be used not only in steel but also in a wide range of fields such as chemistry and medicine. In particular, ICP (Inductively Cou)
The present invention relates to a method for dissolving a sample for chemical analysis, which can be used as an automatic pretreatment such as pleated plasma (high-frequency inductively coupled plasma) emission spectroscopy and atomic absorption spectroscopy.

[0002]

2. Description of the Related Art For example, in order to dissolve a sample for chemical analysis of steel, slag, iron ore, etc., in order to ensure quickness, accuracy and safety, it is necessary to select an appropriate decomposing agent according to the type of the sample, Choose a disintegrant that is compatible with the liquidity in the quantitative system, consider the characteristics of the analytical or co-existing components for the disintegrant,
It is necessary to consider the danger of explosion and fire.
Specifically, decomposers that are almost common in all steel samples are:
It is a combination of aqua regia or hydrochloric acid and nitric acid, but when these are also difficult to decompose, for example, when they contain oxides, carbides, nitrides, etc., it is necessary to separate and melt the acid-insoluble residue and merge them .

Heretofore, most of the dissolution processing of a sample for chemical analysis has been performed manually, resulting in a significant delay in feedback of the analysis result, and it is required to be fully automated or to automate and speed up the main part. I was Conventional melting of a melting sample for chemical analysis by manual operation involves mixing a powdery sample and a melting agent into a platinum crucible, and placing the platinum crucible in an 800 to 12 mm.
Put in an electric furnace at 00 ° C to completely melt the contents inside, and then heat the platinum crucible with a burner etc.
While rocking the platinum crucible by hand using a crucible pinch, as shown in FIG. 4, the sample melt 32 is adhered to a wide range of the inner wall of the platinum crucible 31 to facilitate dissolution of the sample melt 32 in the subsequent steps. . Then, the molten sample was allowed to stand and solidified to solidify, and then, as shown in FIG.
The solidified platinum crucible 31 of the molten sample is put into a container 34 such as a glass beaker containing 3 and placed on a hot plate 35 for 8 minutes.
The dissolution was completed by heating to 0 to 90 ° C. in about 40 to 50 minutes.

[0004] In the above manual melting operation of the melting sample for chemical analysis, the operation of attaching the sample melt 32 to the inner wall of the platinum crucible 31 over a wide area requires not only considerable skill but also high temperature melting at about 1000 ° C. It is dangerous because it is an object, and the workability is poor, such as grabbing and shaking the platinum crucible between crucibles. In addition, it generally takes about 40 to 50 minutes to complete the dissolution of the sample after the melting process, and depending on the skill of the melting process, unmelting remains and reprocessing must be performed. There is a problem that must be.

[0005] As an automatic method for dissolving a melt-processed sample for chemical analysis, a solid sample is loaded into a melting crucible together with a melting aid, heated and melted, cooled and solidified, and then added with an acid and dissolved by heating. In the sample preparation method, the heating and melting of the solid sample in the melting crucible is performed by induction heating in a state where the same crucible is housed in a heat- and acid-resistant container,
After the addition of the acid, a method of heating and dissolving the solidified sample in the crucible while blowing a high-temperature fluid into the heat- and acid-resistant container (Japanese Patent Application Laid-Open No.
No. 4521) has been proposed.

[0006]

Problems to be Solved by the Invention
The method disclosed in Japanese Patent Publication No. 21 can be carried out quickly and reliably without manual operation, but high-temperature fluid is blown into the heat- and acid-resistant container while induction heating is performed while the melting crucible is housed in the heat- and acid-resistant container. Since the coagulated sample in the crucible is heated and dissolved, it is difficult to rapidly dissolve the coagulated sample and to adjust the blowing amount of the high-temperature fluid so that the solution is not scattered.

SUMMARY OF THE INVENTION It is an object of the present invention to dissolve a sample for chemical analysis automatically, quickly, accurately and safely, and to obtain a molten sample for chemical analysis which has an analysis accuracy equal to or higher than that of a conventional method. To provide a method for dissolving

[0008]

Means for Solving the Problems The present inventors have intensively studied and studied to achieve the above object. As a result, the solid sample in the melting crucible is melted by adding a release agent at the time of melting, so that the work for attaching the melt to the crucible inner wall becomes unnecessary, and after being melted, cooled and solidified,
By dissolving the molten crucible in a state in which the melting crucible is accommodated in a container to which the dilute acid has been added, by placing it in an ultrasonic thermostat, 10 to 15
It was determined that the dissolution was completed in minutes, and the present invention was reached.

That is, according to the present invention, a solid sample is charged into a melting crucible together with a melting aid, heated and melted, cooled and solidified, and then heated in an acid solution to melt the solidified sample. In the method, a solid sample is loaded into a melting crucible together with a melting aid and a release agent, and then heated and melted, then cooled and solidified as it is, and the melting crucible is put into an acid solution container and put into an ultrasonic thermostat to dissolve. This is a method for dissolving a melt-processed sample for chemical analysis.

[0010]

In the present invention, a solid sample is loaded into a melting crucible together with a melting aid and a release agent, and is heated and melted, and then cooled and solidified as it is. Even if the sample melt is not adhered over a wide area, the peeling of the sample melt is facilitated by the release agent and the sample melt is easily peeled, so that the dissolution of the sample melt is promoted. Further, the melting crucible is put into the acid solution container and put into an ultrasonic thermostat to dissolve, so that the dissolution is promoted by the vibration of the ultrasonic wave, and the dissolution is completed in a very short time of 10 to 15 minutes. Therefore, unlike the conventional manual operation, it is not necessary to adhere the sample melt to the inner wall of the melting crucible in a wide range, and it is not necessary to perform dangerous and skillful operations.

The melting crucible used in the present invention is required to have excellent acid resistance and to be used continuously because it is put into an acid solution for dissolving a sample melt, and a platinum crucible is generally used. As the melting aid used in the present invention, lithium borate or sodium borate, a mixture of sodium carbonate and sodium bromide, or the like can be used. Further, as the release agent used in the present invention, ammonium iodide, ammonium bromide, ammonium carbonate, ammonium borate, and the like can be used. Further, in the present invention, a solvent having a predetermined concentration, for example, a low-concentration aqueous acid solution such as hydrochloric acid, perchloric acid, or nitric acid can be used as the acid solution for dissolving the sample melt. Also, depending on the type of sample to be dissolved,
Aqua regia, or a combination of hydrochloric acid and nitric acid can also be used.

[0012]

[Example] Total Fe: 0.47% in a platinum crucible,
Blast furnace slag standard sample BS No. of SiO ₂ : 36.39%, CaO: 36.33% 100 (powder sample) 0.1
g, 2.5 g of lithium borate as a melting aid and 2 ml of 4% ammonium iodide as a stripping agent, and charged into an electric furnace at about 1000 ° C. to be melted, and then taken out of the electric furnace. Leave as it is, and as shown in FIG.
Sample melt 1 was solidified. The solidified platinum crucible 2 of the sample melt 1 was hung on a crucible hook 3 made of glass and immersed in an ultrasonic thermostat 4 kept at 100 ° C., as shown in FIG. 6, the crucible hook 3 was lowered to put the platinum crucible 2 into the 3% hydrochloric acid aqueous solution 5, and the ultrasonic wave of 26 kHz was oscillated to dissolve the sample melt 1. The melt was dissolved in 10 to 15 minutes. The total Fe, SiO ₂ , and CaO in the blast furnace slag were analyzed by ICP emission spectroscopy. 1
The average value, the variation width, the standard deviation, and the variation coefficient were obtained by repeating 0 times. The results are shown in Table 1 as the method of the present invention.

For comparison, a blast furnace slag standard sample BS No. was placed in a platinum crucible. 0.1 g of 100 (powder sample)
And 2.5 g of lithium borate as a melting aid, and the mixture was placed in an electric furnace at about 1000 ° C. to be melted. Then, while heating the platinum crucible with a burner or the like, using a crucible sandwicher, While rocking the platinum crucible in the operation, as shown in FIG. 4, the sample melt 32 is adhered to the inner wall of the platinum crucible 31 over a wide area, and the sample melt 32 is cooled and solidified as it is, as shown in FIG. The solidified platinum crucible 31 of the sample melt 32 was put into a glass beaker 34 containing an aqueous solution 33, and this was heated to 80 to 90 ° C. on a hot plate 35 having a surface temperature of about 200 ° C. to be melted.
Since it was dissolved in about 40 to 50 minutes, total Fe, SiO ₂ , and CaO in the blast furnace slag were determined by ICP emission spectroscopy.
Was analyzed. This was repeated 10 times to obtain each average value, variation width, standard deviation, and variation coefficient. The results are shown in Table 1 as a conventional method. Note that the coefficient of variation in Table 1 is a value obtained from the coefficient of variation = (standard deviation / average value) × 100.

[0014]

[Table 1]

[0015] As shown in Table 1, the method of the present invention enables rapid, high-precision and safe chemical analysis, as compared with the conventional method.
Particularly, the analysis accuracy of SiO ₂ , which is difficult to dissolve, is improved. This indicates that the use of the peeling agent and the use of the ultrasonic thermostat sufficiently dissolve the molten sample and sufficiently dissolve the blast furnace slag.

[0016]

As described above, according to the method of the present invention, there is no need for a dangerous and skill-intensive operation for adhering the sample melt to the inner wall of the crucible over a wide area, and the variation in the analytical results resulting from the skill level of the operation is small. Thus, the time required for dissolving the sample melt can be reduced to 1/3 to 5 and the analysis accuracy equivalent to or higher than that of the conventional method can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for dissolving a sample melt according to the method of the present invention in an example.

FIG. 2 is an explanatory view of a state after cooling and solidifying a sample melt melted by the method of the present invention.

FIG. 3 is an explanatory diagram of a conventional method for dissolving a sample melt in a working example.

FIG. 4 is an explanatory diagram showing a situation after cooling and solidifying a sample melt melted by a conventional method.

[Explanation of symbols]

 1,32 Sample melt 2,31 Platinum crucible 3 Crucible hook 4 Ultrasonic oven 5,33 3% hydrochloric acid aqueous solution 6,34 Glass beaker 35 Hot plate

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshihiro Maruta 1850 Minato, Wakayama-shi, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works (56) References JP-A-59-18437 (JP, A) JP-A-58- 50446 (JP, A) JP-A-55-4521 (JP, A) JP-A-5-273132 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 1/28 G01N 33 / 20

Claims (1)

(57) [Claims] In a method for dissolving a sample for chemical analysis, a solid sample is charged into a melting crucible together with a melting aid, heated and melted, cooled and solidified, and then heated in an acid solution to melt the solidified sample. A chemistry characterized by loading a solid sample together with a melting aid and a release agent into a crucible, heating and melting, then cooling and solidifying as it is, then putting the melting crucible into an acid solution container and dissolving it in an ultrasonic thermostat. A method for dissolving a sample for analysis.