JPH06308110A - Method for quantitative analysis of crushing assistant in inorganic powdery body - Google Patents

Abstract

PURPOSE:To correctly determine by instantaneously heating an inorganic powdery body after being crushed, measuring a thermally decomposed product of organic components generated as a crushing assistant by a gas chromatograph with a cooling device, and performing a quantitative analysis from the peak area of each component on the chromatogram. CONSTITUTION:A carrier gas of a gas chromatograph 1 is branched in the middle way, and sent to a Dewar vessel 4 containing a liquid nitrogen 3. In consequence, the nitrogen 3 is sent to a solenoid valve 5 set to a column oven of the chromatograph 1 because of the rise of the internal pressure. The valve 5 is opened. The nitrogen 3 is sprayed until the temperature inside the oven is lowered to a set value. The valve 5 is closed when the temperature becomes not higher than the set value. Accordingly, the temperature of the column can be set suitably. An inorganic powdery body is instantaneously heated by the chromatograph 1 with a cooling device, and a generated thermally-decomposed product of organic components is separated at the low temperature in the column, and subjected to a quantitative analysis from the peak area of each component on the chromatogram. In this manner, organic components added as a crushing assistant in the crushing process can be determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quantitatively analyzing a grinding aid in an inorganic powder.

[0002]

2. Description of the Related Art Conventionally, industrial products made of powders of inorganic compounds such as cement and calcium carbonate powders have high polar organic substances for the purpose of improving pulverizability and reducing energy consumption in the pulverizing process in the manufacturing process. A grinding aid containing a compound as a main component is added.

The added grinding aid generally remains in the product, but the remaining amount of the grinding aid in the product is closely related to the addition amount of the grinding aid in the grinding process and the temperature inside the grinder. However, these have a great influence on the grinding efficiency. Further, the grinding aid remaining in the product may affect the performance of the product, and the effect varies depending on the remaining amount.

Therefore, in order to examine the grinding efficiency and the performance of the product, it is important to quantify the grinding aid remaining in the product, and in particular, problems such as remarkable deterioration of the grinding efficiency and abnormal performance of the product occur. In this case, it is necessary to confirm the residual amount of grinding aid in the product in order to investigate the cause.

Generally, as a grinding aid in the grinding process of inorganic materials such as cement and calcium carbonate, for example,
Polyhydric alcohols such as diethylene glycol and propylene glycol, and amino alcohols such as triethanolamine and triisopropanolamine are used.

Generally, the amount of these grinding aids added is extremely small, and for example, the amount of diethylene glycol used when grinding cement is usually about 0.05% by weight.

Heretofore, no effective method for quantitatively analyzing a trace amount of a grinding aid in such an inorganic material has been reported.

On the other hand, a pyrolysis gas chromatographic method is known as a method for easily and quickly determining the amount of the organic admixture in the cement and the cement hardened product.

In this method, the organic component contained is liberated from the sample by instantaneously heating the cement or the hardened cement product, the generated thermal decomposition product is separated by gas chromatography, and the organic component contained is separated. It is a method of quantifying from the area of the peak due to.

This method does not require pretreatment such as extraction or acid decomposition in order to desorb organic components from the sample by heat, is excellent in rapidity, and the thermal decomposition product is isolated by gas chromatography. Therefore, there is an advantage that it is not affected by other coexisting components.

[0011]

Although it is possible to detect the grinding aid in the inorganic powder by this pyrolysis gas chromatographic method, most of the organic components used as the grinding aid are heated. Since all of the multiple thermal decomposition products produced by the method have extremely low molecular weight, the time to pass through the column of the gas chromatograph (holding time) is short, and the difference is extremely small. The accurate quantification was difficult because the separation was difficult.

That is, usually, in the analysis by the pyrolysis gas chromatograph, the quantitative determination is carried out from the area of the peak which is completely isolated and in which the content of the target organic component and its intensity are in a proportional relationship. Difficult to separate peaks,
Although the detection method itself of the grinding aid in the inorganic powder is possible by the above-mentioned analysis method using the conventional pyrolysis gas chromatograph, accurate quantification cannot be performed.

Further, in gas chromatographic analysis, the column temperature is one of the governing factors that determine the retention time, and it is possible to increase the resolution by measuring at a lower temperature. Since measurement could not be performed at room temperature or below, the measurable temperature range was limited. .

The present invention solves the above-mentioned problems in the conventional pyrolysis gas chromatographic method and enables accurate quantification of the grinding aid in the inorganic powder, and quantitative analysis of the grinding aid in the inorganic powder. The purpose is to provide the law.

[0015]

The inventors of the present invention can measure at a lower temperature by further connecting a column cooling device to a gas chromatograph that can normally measure only at room temperature or higher, and the retention time of components can be increased. The present invention has been accomplished by finding that the above-mentioned object can be achieved by extending the above-mentioned range and improving the separability.

The quantitative analysis method of the grinding aid in the inorganic powder of the present invention is performed by instantaneously heating the pulverized inorganic material with respect to the organic component added as the grinding aid in the pulverization step of the inorganic material. The thermal decomposition products of the organic components are separated at low column temperature using a gas chromatograph equipped with a column cooling device, and quantitatively analyzed from the peak area of each component on the chromatogram.

In the quantitative analysis method of the present invention, the generated thermal decomposition product of the organic component is separated at a low column temperature (a column temperature lower than usual) using a gas chromatograph equipped with a column cooling device.

The column temperature may be equal to or lower than the temperature at which the thermal decomposition products of each organic component in the sample can be detected at a sufficiently long time, and above the temperature at which the thermal decomposition products can maintain a gas state. An appropriate column temperature is set by the column cooling device connected to the Tograph.

Examples of the refrigerant of the column cooling device connected to the gas chromatograph include liquid nitrogen and liquefied carbon dioxide gas, but any refrigerant that can sufficiently cool the column may be used.

In the quantitative analysis method of the present invention, the apparatus used for thermally decomposing the organic component in the sample has a column temperature set when the pyrolysis product is sent to the gas chromatograph, and is above a certain limit. Any gas that has a vapor pressure of

A FID (frame i) is used as a detector.
An orientation detector, a hydrogen flame ionization detector), an infrared spectrophotometer, a mass spectrometer, or the like can be used, as long as it has sufficient sensitivity to the component to be detected.

The quantitative operation is carried out by plotting the area of a peak, of which the area is directly proportional to the target organic component in the sample, in the calibration curve prepared in advance.

In carrying out the present invention, the column cooling device shown in FIG. 1, for example, is used.

When the carrier gas of the gas chromatograph 1 is branched in the middle and flown into the Dewar bottle 4 containing the liquid nitrogen 3, the internal pressure rises, so that the liquid nitrogen 3 is an electromagnetic valve attached to the column oven of the gas chromatograph 1. Go to 5. The solenoid valve 5 is opened, and nitrogen is sprayed until the temperature in the column oven drops to the set value. When the temperature becomes lower than the set value, the solenoid valve 5 closes, and when the temperature rises, it opens again.
Thereby, the column temperature can be set appropriately.

In FIG. 1, 6 indicates a column.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples.

The following conditions apply to all samples in the examples.

(Sample) As the sample to be analyzed, 5 ± 0.05 mg of a sample having a particle size of 150 μm or less, which had been finely pulverized by a planetary mill (planetary ball mill manufactured by Fritsch), was used.

(Apparatus) Pyrolysis apparatus: JHP-2 type Curie point pyrolyzer (manufactured by Nippon Analytical Industry Co., Ltd.) Gas chromatograph: HP5890A (Hewlett
Packard) Detector: HP5970B Mass Spectrometer (Hewlett Packard) Column Cooling Device: HP5890A Cooling Device (Hewlett Packard) Liquid Nitrogen Column: DB-1701 (J & W) 30m × 0.2
5 mmi. d (inner diameter) 0.25 μm f. d (film thickness)
Carrier gas Helium Thermal decomposition temperature: 764 ° C Thermal decomposition time: 10 seconds

Example 1 Quantification of diethylene glycol in cement In FIG. 2, as a comparison, 0.05% diethylene glycol was added.
Column temperature 30 ℃ for cement added by weight%
The gas chromatogram obtained by measuring at (constant) is shown.

As is apparent from FIG. 2, the two peaks observed in the gas chromatogram are close to each other in retention time, and therefore, it is impossible to quantify each peak independently.

FIG. 3 shows a gas chromatogram obtained by measuring the same sample as described above at a column temperature of 5 ° C. by using a gas chromatograph equipped with a column cooling device.

As is apparent from FIG. 3, in the case of the present invention in which the separation and measurement are carried out at a low column temperature, the two peaks are completely separated. Of these, the area of peak 2 corresponds to the amount of diethylene glycol added. A correlation was found.

FIG. 4 shows a calibration curve prepared from cement containing 0.02, 0.04 and 0.06% by weight of diethylene glycol.

As is clear from FIG. 4, a high linearity was obtained in the calibration curve, and a column cooling device was connected to the calibration curve to carry out gas chromatographic analysis at a low column temperature. It can be seen that the residual amount of diethylene glycol can be quantified.

Example 2 Quantification of triethanolamine in cement FIG. 5 shows that 0.05% triethanolamine was used for comparison.
Column temperature 30 ℃ for cement added by weight%
The gas chromatogram obtained by measuring at (constant) is shown.

As is clear from FIG. 5, the two peaks observed in the gas chromatogram are close to each other in retention time, and therefore, it is impossible to quantify each peak independently.

FIG. 6 shows a gas chromatogram obtained by measuring the same sample as above at a column temperature of 5 ° C. by using a gas chromatograph equipped with a column cooling device.

As is clear from FIG. 6, in the case of the present invention in which separation and measurement are performed at a low column temperature, two peaks can be separated by measurement at a low temperature.

FIG. 7 shows a calibration curve prepared from cement containing 0.02, 0.04 and 0.06% by weight of triethanolamine.

As is clear from FIG. 7, a high linearity is obtained in the calibration curve, and the column cooling device is connected to the quantitative analysis method of the present invention for performing gas chromatographic analysis at a low column temperature. It can be seen that the residual amount of triethanolamine can be quantified.

Example 3 Quantification of diethylene glycol in calcium carbonate In FIG. 8, calcium carbonate containing 0.05% by weight of diethylene glycol was measured at a column temperature of 5 ° C. by using a gas chromatograph equipped with a column cooling device. The obtained gas chromatogram is shown.

As is apparent from FIG. 8, the same gas chromatogram as in Example 1 was obtained in which the amount of diethylene glycol in the cement was quantified.

FIG. 9 shows a calibration curve prepared from calcium carbonate containing 0.02, 0.04 and 0.06% by weight of diethylene glycol.

As is clear from FIG. 9, a high linearity was obtained in the calibration curve, and a column cooling device was connected to the quantitative analysis method of the present invention for performing gas chromatographic analysis at a low column temperature. It can be seen that the remaining amount of diethylene glycol can be quantified.

[0046]

According to the quantitative analysis method of the grinding aid in the inorganic powder of the present invention, the grinding temperature of the grinding powder in the inorganic powder, which has been difficult to analyze by the conventional pyrolysis gas chromatographic method, can be measured by the column temperature. It becomes possible to accurately quantify the content of the inorganic powder in the inorganic powder without impairing the advantages of the conventional pyrolysis gas chromatographic method, such as excellent rapidity and being unaffected by other components. Can be quantitatively analyzed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a column cooling device used in the present invention.

FIG. 2 is a diagram showing a gas chromatogram of a cement (0.05% by weight) containing diethylene glycol at a measurement temperature of 30 ° C.

FIG. 3 is a diagram showing a gas chromatogram of cement (0.05% by weight) containing diethylene glycol at a measurement temperature of 5 ° C.

FIG. 4 is a diagram showing a calibration curve of diethylene glycol in cement.

FIG. 5 is a diagram showing a gas chromatogram of cement (0.05% by weight) containing triethanolamine at a measurement temperature of 30 ° C.

FIG. 6 is a diagram showing a gas chromatogram of triethanolamine-added cement (0.05% by weight) at a measurement temperature of 5 ° C.

FIG. 7 is a view showing a calibration curve of triethanolamine in cement.

FIG. 8 is a diagram showing a gas chromatogram of diethylene glycol-added calcium carbonate (0.05% by weight) at a measurement temperature of 5 ° C.

FIG. 9 is a diagram showing a calibration curve of diethylene glycol in calcium carbonate.

[Explanation of symbols]

 1 Gas chromatograph 2 Carrier gas cylinder 3 Liquid nitrogen 4 Dewar bottle 5 Solenoid valve 6 Column

Claims (1)

[Claims] 1. A gas chromatograph equipped with a column cooling device for a thermal decomposition product of an organic component generated by instantaneously heating an inorganic material after pulverization with respect to an organic component added as a pulverization aid in the pulverization step of an inorganic material. A method for quantitatively analyzing a grinding aid in an inorganic powder, which comprises performing a quantitative analysis from a peak area of each component on a chromatogram by separating at a low column temperature using a tograph.