JPH05281170A - Method for determining quantity of moisture in solid - Google Patents

Abstract

PURPOSE:To obtain the highly accurate method for determining the quantity of moisture in solid, which can determine the minute quantity of the moisture and has the excellent operability. CONSTITUTION:Solid such as sulfer is heated to the temperature of 120-200 deg.C in the flow of inactive gas so as to obtain the fused state. The moisture is removed, and the quantity of the moisture is determined. As the inactive gas, argon, nitrogen, helium or the like is used. The moisture, which is adsorbed in the surface of the lump of the solid and the moisture in the lump can be completely extracted into solvent by transforming the solid into the fused state. The minute quantity of the moisture at a p.p.m. lcan be accurately measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quantifying water in a solid, and more particularly to a measuring method for quantifying water in sulfur.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the water content of a solid, there is a gravimetric method. This method is a method in which a solid sample is heated in a dryer and then the weight loss is quantified as water content. In the Karl Fischer coulometric titration method, a solid sample such as sulfur is put into a solvent for extracting water, and the extracted water is reacted with iodine, and iodide is electrolytically oxidized to generate iodine to perform coulometric titration.

[0003]

[Problems to be Solved by the Invention]
According to the conventional method for determining the moisture content of solids, solids contain sulfur.
In this case, according to the above weight loss method, the heating temperature is 60 ° C.
And the water in the sulfur may not be completely removed.
It Further, when the temperature is further increased, sulfur itself becomes SO ₂ age
The problem is that accurate quantification is difficult
is there.

According to the Karl Fischer coulometric titration method described above, when the sulfur is in the form of lumps, it is difficult to extract the water inside the lumps. Further, when the sulfur is powder, there is a problem that the affinity with the solvent is poor and the solid floats on the upper part of the solvent, which makes the measurement operation difficult. Furthermore, it is not possible to quantify a trace amount of water of about several tens of ppm by any of the above methods.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly accurate solid water quantification method which has good operability and is capable of quantifying a small amount of water.

[0006]

The method for quantifying the water content of a solid according to the present invention for solving the above-mentioned problems is a method of heating a solid in an inert gas flow to bring it into a molten state to remove the water content, and quantifying the water content. It is characterized by doing. It is characterized in that the temperature for heating the solid to a molten state is in the range of 120 to 200 ° C.

It is characterized in that the solid is sulfur. At least one of argon, nitrogen and helium is used as the inert gas.

[0008]

By heating the solid in an inert gas to a temperature of 120 to 200 ° C. to bring it into a molten state, the water adsorbed on the surface of the solid mass and the water present in the mass are completely dissolved in the solvent. It can be extracted into the inside and the amount of water can be determined accurately and accurately. According to the present invention, moisture on the surface of the solid and the inside of the solid can be completely removed, and a trace amount of moisture at the ppm level can be accurately measured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. First, a solid moisture quantification device is shown in FIG. Figure 1
Shows the water extraction device 1. In FIG. 1, 1 indicates a heating vaporizer. Sulfur is introduced into the sample boat 3 and inserted into the heating furnace 2. The temperature inside the heating furnace 2 is 1
It is heated to 20 to 200 ° C. to bring sulfur into a molten state, vaporize water, and extract the solvent in the titration cell 5 via the pipe 4.

Details of the titration cell 5 are shown in FIGS. 2 and 3. Into the titration cell 5, a commercially available solvent such as methanol, chloroform, pyridine or the like is previously introduced from the sample charging plug 6. Then, water is introduced into the solvent in the container 8 through the inlet pipe 7 connected to the pipe 4 shown in FIG. Next, the quantitative operation is as follows. The water content in the titration cell 5 is previously titrated to zero. The solid is put in the sample boat 3 in the heating vaporizer 1 and heated to a temperature of 140 ° C. while purging with nitrogen to bring the solid into a molten state and hold it for about 10 minutes to extract water into the solvent. The extracted water content is titrated. The water content of the solid is calculated from the obtained titration value.

Experimental Example 1 Experimental example 1 is an example of analysis by the above quantitative operation. The analysis conditions are sample amount: 2 to 6 g, heating temperature: 140 ° C., inert gas: nitrogen. The results of this analysis are shown in Table 1.

[0012]

[Table 1] Experimental Example 2 Experimental Example 2 is an example of quantifying the water content in the sulfur that has adsorbed the water content. The sample preparation method in this case is as follows. 20 μl of distilled water was added to 20 g of a sulfur sample, which was crushed and mixed in a mortar, and 1 g of this crushed mixed product was taken.
Prepared by milling again with 9 g of sulfur sample.

Table 2 shows the results of analysis by the above quantitative operation.

[0014]

[Table 2] In Table 2, there are variations in the measured values of water content indicated by n of 1 to 5, but this is an error range when considered from the sample preparation method. Next, the coulometric titration method used in the examples of the present invention will be described. 3 and 4 show an example of the coulometric titration device and the coulometric titration cell used in the examples of the present invention.

The coulometric titration cell comprises two chambers, an anolyte chamber 11 and a catholyte chamber 12, and the chambers 11 and 12 are separated by a diaphragm 13 such as ceramics or ion exchange resin.
The diaphragm 13 is made of a material that does not mix the anolyte and the catholyte during electrolysis and has a low electric resistance. The anolyte compartment 11 and the catholyte compartment 12 each have an electrolytic electrode 15 and an indicator electrode for determining the end point of titration. In the atmosphere open part,
It has a drying tube 18 filled with silica gel or the like.

Each part shown in FIG. 4 has the following functions. Polarization current detection unit 20: A constant voltage or constant current is applied to the indicator electrode from a DC or AC power source, and a minute current or minute voltage change in the indicator electrode tube is amplified to detect the end point. Current control unit 21: Controls electrolysis by receiving a signal from the detection amplification unit and intermittently or gradually decreasing the electrolysis current near the end point.

Electrolytic current power source 22: constant current (107.1 m)
A or multiple thereof) or variable current (0 to 500 mA)
Power. End point detection display unit 23: Displays the end of measurement when the polarization voltage or current reaches the set end point value in response to the signal from the detection amplification unit. Current accumulator 24: Accumulates the current required for titration and displays the amount of electricity or the amount of water (μg H ₂ O).

[0018]

As described above, the method for quantifying the water content of a solid according to the present invention has the effect that the minute water content in a solid can be accurately detected.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a heating vaporizer of the present invention.

FIG. 2 is a schematic perspective view showing a titration cell.

FIG. 3 is a schematic configuration diagram showing a titration cell.

FIG. 4 is a schematic configuration diagram showing a titration device.

Claims (4)

[Claims] 1. A method for quantifying moisture in a solid, comprising heating the solid in an inert gas stream to bring it into a molten state, expelling the moisture, and quantifying the moisture. 2. The temperature at which a solid is heated to a molten state is 1
It is in the range of 20 to 200 ° C.
A method for quantifying the water content of a solid as described. 3. The method for quantifying the water content of a solid according to claim 1, wherein the solid is sulfur. 4. The method for quantifying water content in a solid according to claim 1, wherein at least one of argon, nitrogen and helium is used as the inert gas.