SU1599724A1 - Method of spectral analysis - Google Patents

Abstract

This invention relates to emission spectral analysis. The aim of the invention is to reduce the detection limit and increase the sensitivity of the analysis by creating a zone of localized intense emission of spectral lines. In order to realize the goal, a multi-electrode arc is used in the analysis method, which is fed with a unipolar pulsating current. The sample is introduced into the discharge zone between the upper anode electrodes. The radiation is recorded from the cathode region. 2 Il.

Description

This invention relates to emission spectral analysis.

The aim of the invention is to reduce the detection limit and increase the sensitivity of the analysis by creating a zone of localized intense emission of spectral lines.

Figure 1 shows the combustion chamber; Fig. 2 is a power supply diagram of a spectral analysis device.

The device for emission spectral analysis comprises a body 1 of a combustion chamber, inside which is placed a pipe 2 for suctioning gas and a discharge device including electrodes 3-6 (for example, coal) installed at an angle of 50-70 ° relative to the horizontal plane, the ends of which are located in a plane at an angle of 80 and are connected in pairs in a cross-section with systems of low-pole circuits containing separation transformers 7 and 8, current curlers 9 and 10, capacitors 11 and 12, and high-voltage circuits 13 and 14, electrically unrelated. Above the working (svsbodny) ends of the electrodes 4 and 5, the rasiols are the wife of a tube 15, through which the test material is fed 16 D in the direction of the electrodes, 3-6,

.The location of the ends of the electrodes 3 and 6 near the optical axis of the spectral device allows TiptieKTuing to its slit the most intense radiating part of the arc located near the cathode, electrodes 3 and 6, and using the so-called cathodic effect — pr-cathode amplification of spectral lines.

The device works as follows.

A caliber, which enters the interelectrode space, is preliminarily set in motion, springs in the holders (not shown) of the electrodes, and sets the distance between the ends of the electrodes. Using Tube 15 podQD

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A stream of gas, such as air, test material 16, Hanpi-gemer is a geological powder sample with a particle size of less than 20 microns, on top between the working ends of electrodes 4 and 5, the distance between which is greater than the diameter of the jet of supplied gas. Gas is sucked from the body 1 of the combustion chamber through side holes in the pipe 2. Next, voltage is applied to transformers 7-8 and generators-13 and 14 Zyukofrequency pulses. In the inter-electrode gaps of 3.5 and 4.6, the high-frequency discharges, ionizing the J5 interelectrode space, iiTO leads to the occurrence of arc discharges between the electrodes 3.5 and 4.6.

: The plasmas of these bits of space-JseHHo are combined due to the fact that the electric current flows in one direction from the anodic upper electrodes 4 and 5 to the cathodic lower electrodes 3 and 6. It is formed due to the relatively large distance between the upper 4 and 5 and the lower 3 and 6 electrodes (4-6 mm) plasma, narrowed downwards because of the relatively small distance between electrodes 3 and 6, equal to 1-2 mm. To register the spectrum on a spectral instrument, the feed of the material under study 16 is sufficiently continuous and the burning of this discharge takes 15–30 s. I

Such a feed of the material under study into a continuously burning discharge causes the particles to fall into the hottest area of the discharge and move

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When moving along a pole at a relatively low speed, there is a 3-5-fold longer distance therein than when the material is fed across the arc column. An increase in the residence time of the particles of the material under study in the hot zone and the residence time of the very atoms of the elements under study contributes to a more complete evaporation of the particles and an increase in the time for registration of the radiation of atoms.

The invention makes it possible to reduce the lower limit of the determined contents of various elements by almost 5 times and to achieve reproducibility of the results of the analysis, characterized by a relative rms error of about 5%.

Claims (1)

Invention Formula A method of spectral analysis, including waking up the porrka of the material under study through a multi-electrode arc and recording emission radiation, characterized in that, in order to reduce the detection limit and increase the sensitivity of the analysis by creating a zone of localized intense radiation of spectral lines, the multi-electrode arc is powered by a unipolar pulsating current wherein the powder is introduced between the upper anode electrodes in the direction of the lower cathode electrodes located at a distance of 3-4 times smaller than the upper, and radiation is recorded in the cathode region. Phie. one