JPS6038657B2 - Spectroscopic analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spectroscopic analysis method for elemental analysis of a sample using a spectrometer, and particularly to a method for automatically correcting a calibration curve necessary for analysis.

As part of the product management of cast products, we create a sample by sampling the molten metal before Western-style bathing, perform spectroscopic analysis of this sample with a spectrometer, detect the elemental content of the lacquerware, and properly manage the elemental content within the appropriate range. Conventionally, testing has been carried out to determine whether or not this is the case, and in practice, this analysis line is automated.

In this type of spectroscopic analysis of the amount of elements, the intensity of the wavelength specific to the element to be detected in the discharge spectrum is measured, and the intensity is compared with a calibration curve to determine where it falls on the calibration curve. A method is being used to measure the content (%) of the element. In this case, the calibration curve is obtained by spectroscopically analyzing samples with clear component ratios in advance and from the analysis results of samples with various component ratios. Because it fluctuates in response to changes in I was about to perform elemental analysis. The present invention provides a spectroscopic analysis method that automates the conventional manual measurement of a calibration curve, periodically interrupts the sample analysis line, measures the calibration curve, and corrects the calibration curve. is intended to provide. Hereinafter, the method of the present invention will be explained in more detail based on the illustrated embodiments.

In Fig. 1, reference numeral 1 applies a high voltage between the sample loaded in the sample loading section 2 and the electrode, and the discharge generated at that time is transferred to the spectrometer 3.
spectrometer, which measures the spectral intensity of each spectrum with a side light device 4, and inputs the measured values into a computer 5 to detect the element content in the sample; 6 chucks the sample to be analyzed; 8, polished by a polisher 9, washed with water by a washing device 10, dried the washed sample by an air nozzle 11, and then transferred to the sample loading section of the spectrometer 1 by a rotary arm 12 for sample loading. 2 is loaded into an automatic sample preparation device, and 13 is a sample sending case called a pneumatic feeder sent by an air shooter 18 from each on-site air station 14, 15, 16, 17 installed at each site such as a melting furnace. It is an operating machine that receives the stored sample and returns the empty air charcoal cartridge to the sending site air station again by air ash 18. The received sample is carried into automatic sample preparation device 6 by transfer arm 19.

These automatic sample preparation device 6 and operation device 13 are sequence-controlled by a sequencer 201 connected to the computer 5, and in the order specified by the computer 5,
The sample whose type has been determined is prepared and supplied to the spectrometer 1. On the other hand, 21 is a standardized robot that interrupts the analysis line based on instructions from the computer 5, and as shown in FIG. 2, standardized samples a,, a2, . . The standardization arm 2 grabs the standardized samples a, a2, etc. located at the position, loads them into the sample loading section 2 of the spectrometer 1, and subjects them to spectroscopic analysis.
It has 3.

In addition, when the standardized sample at the forefront of the row is taken out, the sample stage 22 moves the row forward by one sample.
Advance the next standardization sample to the front. The standardization arm 23 has a base supported by a rotation device 24, and standardization samples a, a2, . . . taken out from the sample stage 22.
The standardized sample is loaded into the sample loading section 2, and the standardized sample is placed on an electrode (not shown) so that measurements can be made at multiple different locations during analysis.

) is provided with a rotation mechanism (not specifically shown) that rotates eccentrically with respect to the sample. When the measurement is completed, the grip is released during the return and the sample is dumped into the waste chute 25. Next, the analysis process performed by the computer 5 will be explained according to the flowchart shown in FIG.

First, in step (2), the time is read and it is determined whether it is the standardized time or not, that is, whether it is the same time of the calibration curve.If it is not the standardized time, normal online analysis is performed in step Sometimes, interrupt processing for standardization is performed after step (2). Normal online analysis ~ In step ■, the sample is transferred to the automatic sample preparation device
Determine whether or not the destination has arrived, and if it has arrived,
Necessary information such as the sample number is input to the sequencer 20', and grinding of the sample is started in step 2. Thereafter, the ground sample is washed with water and dried to prepare the sample.

During this sample preparation, the rotating arm 12 is reversed (step ■), the analyzed sample is discarded midway (step ■),
Next, the ground sample is gripped by the rotary arm 12 (step ■), the rotary arm 12 is rotated in the normal direction, and the gripped sample is set in the sample loading section 2 of the spectrometer 1 (step ■,
■).

The set sample is repeatedly subjected to spectroscopic analysis at multiple locations using the spectrometer 1, the spectral intensity at each location is read using the side light device 4, and the average value of the leakage light values is calculated using the computer 5 as shown in FIG. The amount of the element is calculated from the position on the calibration curve by comparing it with a calibration curve (step 2), and the result is printed out using the printer 30 (see FIG. 1) (step 2).

Then, in step (2), an inquiry is made as to whether or not the next sample has been adjusted. If the adjustment has been completed, the spectroscopic analysis from step (2) is started; if the adjustment is not completed, the rotating arm 12 is reversed. The sample is left on standby (step (2)), returns to step (2), and inquires whether it is the standardization time. If it is not the standardization time, online sample analysis is performed from step (2) onwards. On the other hand, if the standardization time corresponds to the standardization time, in step ■, an inquiry is made as to whether the online sample is being adjusted, and in step ■, an inquiry is made as to whether the online sample is being analyzed. In the following sections, an interruption analysis will be performed to correct the calibration curve.

If the online sample is being prepared, return to step ■ to perform spectroscopic analysis on the sample being prepared first, and if it is currently being analyzed, return to step ■ to complete the analysis. Return to

In interrupt analysis, the computer program is switched to a standardization program in step (2), and then the rotary arm 12 is reversed (from step (2) onwards, the rotary arm 12 is kept on standby at the neutral position (step (2)).

Next, in step (2), the standardization arm 23 is reversed, and the standardization sample, for example a, specified by the computer 5 is grabbed (step (2)), and in step (2), the standardization arm 23 is rotated forward, and the sample loading section 2 of the spectrometer 1 is (Step ■).

The loaded standardized sample a is measured at three points in total while changing its position each time in step (2), and the measurement results are verified in step (2).

This test selects the maximum and minimum values among the measured values,
This is done by checking whether the difference is within a preset tolerance range. If the result of this test is good, the computer 5 calculates the average value of the three measured values. Then, use the average value as the spectral intensity of the standardized sample.

Then, reverse the standardization arm 23 (step ■),
During this process, the measured standardization sample is dumped into the disposal chute 25, and an inquiry is made as to whether or not the standardization work has been completed in step ■.If the standardization work should be continued, steps ■ to ■ are repeated, and each standardization The samples were sequentially subjected to spectroscopic analysis, and the measurement results of a total of six standardized samples a, whose carbon content was known in advance are shown in the following table.

A carbon calibration curve is determined based on a total of six measured values obtained in this way. The obtained calibration curve is shown in Figure 4. In this case, the calibration curve Q is a quadratic function of the content x = ax2 + b
Assuming that x+c, constants a, b, c are calculated using the maximum 4 square method, etc.
Determine by asking for .

On the other hand, if the test result is poor in the above test, proceed to step (2), change the sample position, and perform the fourth measurement in step (2). Among the four measured values,
Select a combination of three measured values and re-verify in step ■ whether the combination is within the allowable error range. If the test passes, proceed to step ■ and proceed to the next step. Perform analysis of standardized samples. If the sample still fails the retest, the 0 standardization arm 23 is reversed in step ■, and the standardized sample is discarded as a defective product during the reversal in step ■, and the process proceeds to step ■, which is the same as the one that was discarded. Perform spectroscopic analysis on various standardized samples.

When one calibration curve setting is completed in the above manner, the standardization work is stopped until the next standardization by the standardization work end signal (step ■), the standardization time signal is canceled in step ■, and the program of the computer 5 is stopped. Switch from the standardization program to the normal online analysis program (step ■), and rotate the rotating arm 12 in the normal direction (step ■)
, the sample is placed on standby on the spectrometer 1 (step ①), and the process proceeds to on-line analysis starting from step ②, where elemental analysis is performed based on the corrected calibration curve. As is clear from the above description, the present invention provides a spectroscopic analysis method that automates the correction of a calibration curve, which has conventionally been done manually. It is possible to reliably perform the analysis at a fixed time, to fully automate the conversion of this type of analysis line, and to have the advantage of being able to conduct online analysis completely unmanned for two hours.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall system diagram of the spectroscopic analysis line according to the present invention, Fig. 2 is an enlarged schematic plan view of the standardization device shown in Fig. 1, and Fig. 3 is a flowchart showing a computer-controlled process. , FIG. 4 is a gelatin diagram showing a calibration curve for carbon obtained by the method of the present invention.

1... Spectrometer, 2... Sample loading section, 4... Side light device, 5... Computer,
6... Automatic sample preparation device, 12... Rotating arm, 21... Standardization robot, 22... Standardization arm, a, -... Standardization sample.

Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. When the sample sampled from the molten metal before pouring is sent to the analysis line, it is sent to the automatic sample preparation device according to the computer program, and after polishing, it is set in a spectrometer and the amount of components is analyzed using a calibration curve. In the method of Switch to the standardization program, take out a standard sample from the standard sample palette, set it in the spectrometer, perform spectroscopic analysis at any number of points, use the standard sample whose analytical value falls within the predetermined range as the calibration sample, and set it in the spectrometer. A spectroscopic analysis method characterized by calibrating a calibration curve based on the average value of sample analysis values and then switching from a standardization program to a normal analysis program.