Zinc liquid detection method based on LIBS technology

Abstract

The present invention belongs to the field of optoelectronic analysis, and particularly relates to a method for detecting zinc liquid based on LIBS technology, including a detection stage; the detection stage is as follows: the excitation light repeatedly excites the zinc liquid, and there are bottom slag and surface slag in the zinc liquid, generating N plasma spectra; obtaining the light intensity of iron and the light intensity of aluminum in each spectrum; screening out m spectra corresponding to the bottom slag and the surface slag, and (N - m) spectra corresponding to normal zinc liquid; obtaining the content a of aluminum and the content b of iron in the zinc liquid by using the (N - m) spectra; in the m spectra, if the ratio of the light intensity of iron to the light intensity of aluminum in the spectrum is greater than 1, the spectrum corresponds to the bottom slag, otherwise, the spectrum corresponds to the surface slag; obtaining the concentration C1 of the bottom slag by using n spectra corresponding to the bottom slag, and obtaining the concentration C2 of the surface slag by using (m - n) spectra corresponding to the surface slag. The present invention realizes the calculation of the concentrations of the bottom slag and the surface slag, provides guidance for adding zinc-aluminum alloy, and saves costs.

Description

Technical Field

[0001] The invention relates to photoelectric analysis, and in particular to a zinc liquid detection method based on LIBS technology. Background Art

[0002] No matter what measures are taken for hot-dip galvanizing of products, a certain amount of iron will inevitably enter the liquid zinc in the zinc pot through various reactions, oxidation and corrosion. This element will react with Zn to produce zinc slag. Zinc slag is divided into bottom slag and surface slag. The surface slag has a low density and floats on the surface of the zinc liquid, while the bottom slag has a high density and settles at the bottom of the zinc liquid. Bottom slag will cause a lot of waste and seriously affect the surface and performance of the strip. Large areas of bottom slag will also cause wear of the zinc pot rollers and various defects such as zinc ash and zinc particles on the surface of the strip.

[0003] At present, the treatment of zinc slag in hot-dip galvanizing pots is often done by adding Zn-Al alloy to convert bottom slag into surface slag for easy scooping. However, since it is impossible to calculate the content of surface slag and bottom slag in zinc liquid, the amount of Zn-Al alloy added is often based on experience. This process will cause a lot of waste of resources. Summary of the invention

[0004] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a zinc liquid detection method based on LIBS technology.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A zinc liquid detection method based on LIBS technology includes a detection stage, wherein the detection stage is:

[0007] The excitation light excites the zinc liquid multiple times, and the zinc liquid contains bottom slag and surface slag, generating N plasma spectra;

[0008] Obtain the intensity of aluminum and iron in each spectrum;

[0009] Screening out m spectra corresponding to the bottom slag and the surface slag, and (Nm) spectra corresponding to normal zinc liquid;

[0010] Using the (Nm) spectra, the aluminum content a and the iron content b in the zinc liquid are obtained;

[0011] In the m spectra, if the ratio of the light intensity of iron to the light intensity of aluminum in the spectrum is greater than 1, the spectrum corresponds to bottom slag, otherwise, the spectrum corresponds to surface slag;

[0012] The concentration C1 of the bottom dross is obtained using n spectra corresponding to the bottom dross, and the concentration C2 of the surface dross is obtained using (mn) spectra corresponding to the surface dross.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The spectral element lines are excited by LIBS (laser induced breakdown spectroscopy) technology, and then the spectra corresponding to the surface slag and bottom slag are screened out, and then the surface slag spectrum and the bottom slag spectrum are identified. Finally, the surface slag and bottom slag contents are calculated by the physical model of the present invention, so as to control the Zn-Al alloy addition content. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0016] Figure 1 It is a schematic flow chart of the zinc liquid detection method based on LIBS technology of the present invention;

[0017] Figure 2 is a schematic diagram of the light intensity distribution of aluminum in N spectra of the present invention;

[0018] Figure 3 is a schematic diagram of the spectrum of bottom slag of the present invention;

[0019] Figure 4 This is a schematic diagram of the surface residue spectrum of the present invention;

[0020] Figure 5 It is a schematic diagram of the light intensity ratio of the present invention. DETAILED DESCRIPTION

[0021] Figure 1-Figure 5 The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents.

[0022] Example 1.

[0023] A zinc liquid detection method based on LIBS technology includes a detection stage, such as Figure 1 As shown, the detection stage is:

[0024] The excitation light excites the zinc liquid multiple times, and the zinc liquid contains bottom slag (FeZn7Al) and surface slag (Fe2Al5Zn), generating N plasma spectra;

[0025] Obtain the intensity of aluminum and iron in each spectrum;

[0026] Screening out m spectra corresponding to the bottom slag and the surface slag, and (Nm) spectra corresponding to normal zinc liquid;

[0027] Using the (Nm) spectra, the aluminum content a and the iron content b in the zinc liquid are obtained;

[0028] In the m spectra, if the ratio of the light intensity of iron to the light intensity of aluminum in the spectrum is greater than 1, the spectrum corresponds to bottom slag, otherwise, the spectrum corresponds to surface slag;

[0029] The concentration C1 of the bottom dross is obtained using n spectra corresponding to the bottom dross, and the concentration C2 of the surface dross is obtained using (mn) spectra corresponding to the surface dross.

[0030] In order to accurately obtain the concentrations of bottom slag and surface slag, further, the concentration C1 of the bottom slag and the concentration C2 of the surface slag are respectively:

[0031] ,

[0032] ;

[0033] ρ1, ρ2, ρ3, ρ4, and ρ5 are the densities of bottom slag, surface slag, zinc, aluminum, and iron, respectively.

[0034] In order to accurately obtain the light intensity, further, the light intensity of aluminum is the ratio of the aluminum spectrum intensity at a wavelength of 309.2nm to the zinc spectrum intensity at a wavelength of 206.2nm, and the light intensity of iron is the ratio of the iron spectrum intensity at a wavelength of 302.1nm to the zinc spectrum intensity at a wavelength of 206.2nm.

[0035] In order to screen out the spectra corresponding to the bottom slag and the surface slag, further, the screening method is:

[0036] Perform Gaussian fitting on N spectral data and calculate their confidence interval. The number of spectra outside the confidence interval is m.

[0037] Example 2.

[0038] An application example of the zinc liquid detection method based on LIBS technology in Example 1 of the present invention.

[0039] In this application example, the substances present in the galvanizing pot are generally effective Al, dissolved Fe, surface slag Fe2Al5Zn and bottom slag FeZn7Al. The bottom slag density ρ1=7.25 g / cm 3 , surface slag density ρ2 = 4.1g / cm 3 , the density of Zn is ρ3=7.14 g / cm 3 , the density of Al is ρ4=2.7g / cm3 , the density of Fe is ρ5=7.86g / cm 3 .

[0040] Normally, the Al content in the galvanizing pot is controlled at 0.2~0.23wt%, the Fe content is 0.0111~0.0115wt%, and the rest is Zn liquid. The Al content in the surface slag Fe2Al5Zn is 43.24wt%, the Fe content is 35.8wt%, and the Zn content is 20.96wt%. The Al content in the bottom slag FeZn7Al is 4.9912wt%, the Fe content is 10.331wt%, and the Zn content is 84.6778wt%.

[0041] The zinc liquid detection method based on LIBS technology in this embodiment is as follows: Figure 1 As shown, the detection stage is:

[0042] The zinc solution was excited using a LIBS analyzer, and N = 1200 spectra were obtained.

[0043] The relative intensity of aluminum (the ratio of the aluminum spectrum intensity at a wavelength of 309.2 nm to the zinc spectrum intensity at a wavelength of 206.2 nm) and the relative intensity of iron (the ratio of the iron spectrum intensity at a wavelength of 302.1 nm to the zinc spectrum intensity at a wavelength of 206.2 nm) in each spectrum were obtained.

[0044] like Figure 2 As shown in the figure, the distribution of 1200 relative intensity values ​​of aluminum is then normalized to calculate the number of spectra within the 95% confidence interval. After calculation, the number of spectra within the 95% confidence interval is 1005 (i.e., Nm), so m=195.

[0045] After averaging 1005 spectra to obtain a spectrum, it was brought into the Al and Fe element calculation model to obtain the molten aluminum element concentration a = 0.22wt%, and the effective iron element concentration b = 0.013wt%. The calculation model is an existing technology in the field of LIBS technology.

[0046] like Figure 3 As shown in the spectrum of bottom slag FeZn7Al, the Fe content is higher, so Fe 302.1nm Spectral intensity ratio Al 309.2nm High spectral intensity.

[0047] like Figure 4 As shown in the spectrum of Fe2Al5Zn slag, due to the high Al content, Al 309.2nm Spectral intensity ratio Fe 302.1nm High spectral intensity.

[0048] In m = 195 spectra, the ratio of the relative intensity of iron to the relative intensity of aluminum in the spectrum is obtained, such as Figure 5 As shown in FIG. 1 , if the ratio is greater than 1, the spectrum corresponds to bottom slag, otherwise, the spectrum corresponds to surface slag. According to this method, the number of spectra corresponding to bottom slag is n=82, and the number of spectra corresponding to surface slag is mn=113.

[0049] The concentration of bottom slag C1 and the concentration of surface slag C2 are respectively:

[0050] .

[0051] .

Claims

1. A zinc liquid detection method based on LIBS technology, comprising a detection stage; characterized in that: The detection phase is: The excitation light excites the zinc liquid multiple times, and the zinc liquid contains bottom slag and surface slag, generating N plasma spectra; Obtain the intensity of aluminum and iron in each spectrum; Screening out m spectra corresponding to the bottom slag and the surface slag, and (Nm) spectra corresponding to normal zinc liquid; Using the (Nm) spectra, the aluminum content a and the iron content b in the zinc liquid are obtained; In the m spectra, if the ratio of the light intensity of iron to the light intensity of aluminum in the spectrum is greater than 1, the spectrum corresponds to bottom slag, otherwise, the spectrum corresponds to surface slag; the light intensity of aluminum is the ratio of the intensity of the aluminum spectrum at a wavelength of 309.2nm to the intensity of the zinc spectrum at a wavelength of 206.2nm, and the light intensity of iron is the ratio of the intensity of the iron spectrum at a wavelength of 302.1nm to the intensity of the zinc spectrum at a wavelength of 206.2nm; the bottom slag is FeZn7Al, and the surface slag is Fe2Al5Zn; The concentration C1 of the bottom slag is obtained by using n spectra corresponding to the bottom slag, and the concentration C2 of the surface slag is obtained by using (mn) spectra corresponding to the surface slag; ， ； ρ1, ρ2, ρ3, ρ4, and ρ5 are the densities of bottom slag, surface slag, zinc, aluminum, and iron, respectively.

2. The zinc liquid detection method based on LIBS technology according to claim 1, characterized in that: The screening method is: Perform Gaussian fitting on N spectral data and calculate their confidence interval. The number of spectra outside the confidence interval is m.

3. The zinc liquid detection method based on LIBS technology according to claim 1, characterized in that: The (Nm) spectra are averaged and the aluminum content a and the iron content b in the zinc liquid are obtained using a calculation model.

4. The zinc liquid detection method based on LIBS technology according to claim 3, characterized in that: The content and concentration are in percentage by mass.

5. The zinc liquid detection method based on LIBS technology according to claim 1, characterized in that: The way to stimulate zinc liquid is: The laser is incident into the isolation cylinder with an opening at the lower end, and is incident on the zinc liquid that enters the isolation cylinder from the opening at the lower end.

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