Method for rapidly detecting content of heavy metals in fly ash pickling solution

Abstract

The invention discloses a method for rapidly detecting the content of heavy metals in a fly ash pickling solution, which comprises the following steps: determining main heavy metal elements in the fly ash pickling solution according to an energy spectrum diagram of the fly ash pickling solution, and preparing a simulated fly ash pickling solution; iCP detection is conducted on the simulated fly ash pickling solution, and a standard value is determined; preparing a simulated fly ash pickling solution with gradient concentration according to the standard value, performing XRF detection, and drawing a standard curve; and detecting the fly ash pickling solution sample to be detected by adopting an XRF (X-Ray Fluorescence) method. According to the characteristics of an existing XRF instrument, proper detection accessories are selected to simplify the pretreatment means, the detection time of heavy metal elements in the pickling solution is shortened, and the multi-element simulated fly ash pickling solution is prepared by using a high-purity agent, so that the coverage types and content ranges of XRF fly ash pickling solution multi-element detection marking lines are controllable; and the flexibility of detection indexes and the accuracy of results are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical detection, and in particular relates to a method for quickly detecting the heavy metal content in fly ash pickling liquid. Background Art

[0002] As an emerging waste treatment technology that replaces traditional landfill and composting, waste incineration has the advantages of good volume reduction, energy recovery, high treatment efficiency and environmental friendliness. However, the flue gas and residual derivatives of waste incineration generated by the technology have become a new potential threat to environmental protection. In order to properly handle and reduce the new environmental load, the company cools the flue gas through the chimney and adds lime to mix with the residual derivatives of waste incineration to form a new residue - incineration fly ash.

[0003] Fly ash contains a variety of heavy metal elements and has a complex composition. At present, the main methods for the disposal of fly ash include chelation solidification, landfill, and resource utilization. The ICP-MS method that can accurately detect the raw ash content in fly ash has disadvantages such as complex pretreatment, long detection time, and low data timeliness. It is difficult to provide timely and accurate results for reference in the research on the resource utilization of fly ash produced every day.

[0004] X-ray fluorescence spectroscopy (XRF) is mainly used to analyze elemental composition. It has a wide range of uses, not only for the analysis of solids, powders, foils, melts and gases, but also for solution analysis, etc. It can analyze large-scale samples containing a large number of elements, provide a general overview of the distribution of the measured substances, and allow for qualitative and quantitative analysis. It has a wide range of analyzed elements, fast analysis speed, low sample consumption, good result reproducibility, high analysis precision, simple sample preparation, and no need for pre-treatment. It has significant advantages in qualitative and semi-quantitative analysis, and can effectively improve the dilemma of untimely provision of fly ash element content data.

[0005] Patent application CN118837393A, a portable X-ray fluorescence spectrometry water quality heavy metal detection device and method, has the problem that the detection means of pickling liquid has a complex pre-treatment procedure and a long detection time. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies existing in the prior art and provide a method for rapid detection of heavy metal content in fly ash pickling solution. Through the multiple metal element analysis method of the XRF spectrometer, hydrochloric acid, calcium hydroxide, calcium oxide, potassium chromate, manganese sulfate, ammonium ferrous sulfate and other reagents are used to form a simulated fly ash pickling solution. By gradient detection of the simulated pickling solution, a fly ash pickling solution standard curve is formed to determine the concentration of metal elements in the sample fly ash, thereby achieving the purpose of fly ash resource utilization data detection and collection. According to the characteristics of the existing XRF instrument, suitable detection accessories are selected to simplify the pre-treatment means and shorten the detection time of heavy metal elements in the pickling solution. Use high-purity reagents (impurity content ≤ 0.001%) to configure a multi-element simulated fly ash pickling solution to achieve the XRF fly ash water wash liquid multi-element detection line coverage type, content range controllable, improve the flexibility of the detection index and the accuracy of the results.

[0007] The present invention discloses a method for quickly detecting the content of heavy metals in fly ash pickling liquid, the method comprising the following steps:

[0008] S1. Determine the main heavy metal elements in the fly ash pickling solution according to the energy spectrum of the fly ash pickling solution, and prepare a simulated fly ash pickling solution;

[0009] S2. Perform ICP testing on the simulated fly ash pickling solution to determine the standard value;

[0010] S3. According to the standard value, a simulated fly ash pickling solution with a gradient concentration is prepared, XRF detection is performed, and a standard curve is drawn;

[0011] S4. Use XRF method to detect the fly ash pickling liquid sample to be tested.

[0012] In the above method, further, in S1, the main heavy metal elements in the ash pickling solution include: chromium, copper, zinc, cadmium, manganese, and iron.

[0013] In the above method, further, in S1, the method for preparing the simulated fly ash pickling solution comprises: mixing potassium chromate, copper sulfate, zinc sulfate, cadmium sulfate, manganese sulfate, ammonium ferrous acid and simulated base fly ash in a mass ratio of 3.73:3.93:4.40:2.28:3.08:4.98:77.6, and adding hydrochloric acid to dissolve.

[0014] In the above method, further, the components of the base include calcium carbonate, calcium chloride, calcium hydroxide, sodium chloride and potassium chloride; the mass ratio of the calcium carbonate, calcium chloride, calcium hydroxide, sodium chloride and potassium chloride is 8-10:1:1-2:0.6-1:0.6-1.

[0015] In the above method, further, in S3,

[0016] The XRF detection standard curve of chromium content is: y = 0.9999x + 0.0173;

[0017] The XRF detection standard curve of manganese content is: y = 0.9921x + 0.7409;

[0018] The XRF standard curve for iron content detection is: y = 0.9922x + 0.7595;

[0019] The XRF detection standard curve for copper content is: y = 0.995x + 0.8701;

[0020] The standard curve of zinc content XRF detection is: y = 0.9998x + 0.01782

[0021] The XRF detection standard curve of cadmium content is: y=1.0077x-5.3606.

[0022] In the above method, further, in S4, the fly ash pickling liquid sample to be tested is filtered using a syringe needle filter membrane, placed in an XRF sample cup, fully wrapped with a polycarbonate film, and small holes are pierced on the surface to ensure that the pressure in the sample cup is equal to the atmospheric pressure.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] (1) The present invention provides a method for rapid detection of heavy metal content in fly ash pickling liquid. The fly ash pickling liquid is pretreated by direct syringe filtration and a polycarbonate film is used to fully wrap the sample cup. Compared with the traditional method, the sample pretreatment steps are simplified and the sample pretreatment time is shortened.

[0025] (2) The present invention provides a method for rapid detection of heavy metal content in fly ash pickling liquid. The fly ash pickling liquid sample is detected by XRF. Compared with traditional ICP-MS detection, it can effectively reduce the detection time and ensure the accuracy of the data, providing a scientific and effective reference for subsequent experimental development and process adjustment.

[0026] (3) The present invention provides a method for rapid detection of heavy metal content in fly ash pickling solution, which uses high-purity reagents (impurity content ≤ 0.001%) to prepare multi-element simulated fly ash pickling solution to achieve XRF fly ash water washing solution multi-element detection line coverage type and content range controllable, thereby improving the flexibility of detection indicators and the accuracy of results. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

[0028] Figure 1This is a flow chart of the method for rapid detection of heavy metal content in fly ash pickling liquid in Example 1 of the present invention.

[0029] Figure 2 This is the energy spectrum of daily fly ash pickling liquid in Example 1 of the present invention.

[0030] Figure 3 This is the standard curve for XRF detection of chromium content in fly ash pickling solution.

[0031] Figure 4 This is the standard curve for XRF detection of manganese content in fly ash pickling liquid.

[0032] Figure 5 This is the XRF detection standard curve for iron content in fly ash pickling liquid.

[0033] Figure 6 This is the XRF detection standard curve for copper content in fly ash pickling solution.

[0034] Figure 7 This is the standard curve for XRF detection of zinc content in fly ash pickling solution.

[0035] Figure 8 This is the standard curve for XRF detection of cadmium content in fly ash pickling solution. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0037] The materials, reagents and instruments used in the following examples can all be purchased from commercial channels. The experimental methods in the following examples are all conventional methods in the art unless otherwise specified.

[0038] Example 1

[0039] A method for rapid detection of heavy metal content in fly ash pickling liquid. The detection process is shown in Figure 1 , specifically including the following steps:

[0040] (1) Rapid detection and analysis of multi-element fly ash pickling liquid: The daily fly ash pickling liquid is placed in an XRF sample cup and put into the XRF instrument for detection. The components of the daily fly ash pickling liquid are qualitatively analyzed according to the specific peak time of each element.

[0041] Figure 2 This is the XRF qualitative detection of daily fly ash pickling liquid energy spectrum, and the two figures are characteristic peak spectra of different elements. It can be seen from the figure that daily fly ash pickling liquid mainly contains six heavy metals: chromium, copper, zinc, cadmium, manganese and iron.

[0042] (2) Selection of elements to be tested and configuration of simulated fly ash pickling solution: Six heavy metal elements were selected based on the distribution of significant characteristic peaks in the energy spectrum of daily fly ash pickling solution to draw the XRF multi-element detection standard curve. The reagents and dosages corresponding to the target elements are shown in Table 1.

[0043] Table 1: The corresponding agents and dosages for 6 heavy metal elements.

[0044]

[0045] According to the dosage in Table 1, the configuration of the simulated fly ash pickling solution is as follows:

[0046] Weigh 3.73g of potassium chromate, 3.93g of copper sulfate, 4.40g of zinc sulfate, 2.28g of cadmium sulfate, 3.08g of manganese sulfate, and 4.98g of ammonium ferrous sulfate, and mix with 77.6g of simulated fly ash base (the formula of simulated fly ash base is: 10 parts by mass of calcium carbonate, 1 part by mass of calcium chloride, 1 part by mass of calcium hydroxide, 0.6 parts by mass of sodium chloride and 0.6 parts by mass), grind, add appropriate amount of pure water, mix well, slowly add 1+3 hydrochloric acid to dissolve, and then make up to volume in a 1000ml volumetric flask.

[0047] Due to the influence of the matrix effect of the XRF instrument, the formula of the simulated fly ash base will have a certain fluctuation range according to the changes in the actual fly ash element composition. The mass ratio of calcium carbonate, calcium chloride, calcium hydroxide, sodium chloride and potassium chloride can be 8-10:1:1-2:0.6-1:0.6-1.

[0048] (3) ICP detection of simulated fly ash pickling liquid to determine the standard value: the multi-element mixed standard was digested with nitric acid and its standard value was detected on ICP-MS. Table 2 is the result table of the standard value detected on ICP-MS.

[0049] Table 2: Results of the standard values ​​detected by ICP-MS

[0050] Unit (mg / L) Cr Mn Fe Cu Zn Cd BZR 997 990 991 994 986 978

[0051] (4) Configuration of simulated gradient fly ash pickling solution standard sample:

[0052] 4.1. Sample pretreatment: Filter the simulated fly ash acid wash liquid directly with a syringe needle filter membrane (since the detection range of this method is large, the filtration method can be directly simplified for the filtration steps of the fly ash acid wash liquid). Take about 10mL of filtrate in the XRF sample cup, and use a polycarbonate film at the bottom of the sample to ensure the integrity of the sample and the accuracy of the instrument detection. Before closing the sample cup lid, use a polycarbonate film to cover the surface of the sample cup again and pierce small holes on the surface to ensure that the pressure inside the sample cup is equal to the atmospheric pressure.

[0053] 4.2. According to the test results in Table 2, the gradient volume simulated fly ash pickling solution was taken and fixed to volume in a 50 mL volumetric flask to obtain the simulated fly ash pickling solution multi-element mixed standard samples: BZRY-1, BZRY-2, BZRY-3, BZRY-4, BZRY-5, BZRY-6, BZRY-7, and their standard values ​​were obtained after ICP-MS detection. The test results are listed in Table 3.

[0054] Table 3: Standard value results table of multi-element mixed standard samples.

[0055]

[0056] (5) Drawing of standard curve of multi-element fly ash pickling solution:

[0057] The sample was placed in the XRF, and the "Fly ash pickling liquid multi-element" method was selected in the instrument operation interface to perform sample detection. After the simulated gradient XRF detection value was obtained, it was connected with the corresponding standard value in Table 1 to draw a standard curve of the element to be tested.

[0058] Figure 3 This is the XRF detection standard curve for chromium content in fly ash pickling solution; Figure 4 It is the XRF detection standard curve of manganese content in fly ash pickling solution; Figure 5 This is the XRF detection standard curve for iron content in fly ash pickling solution; Figure 6 This is the XRF detection standard curve for copper content in fly ash pickling solution; Figure 7 This is the XRF detection standard curve for zinc content in fly ash pickling solution; Figure 8 This is the standard curve for XRF detection of cadmium content in fly ash pickling solution.

[0059] (6) Accuracy and reproducibility test of simulated fly ash pickling solution:

[0060] The accuracy and reproducibility of the standard curve were tested by retesting the simulated fly ash acid wash solution standard samples at different times. The test results are listed in Table 4.

[0061] Table 4: Test results of standard samples of simulated fly ash pickling solution.

[0062]

[0063]

[0064] From the results in Table 4, it can be seen that the relative deviation and standard error of the return test results of each element in the standard sample of simulated fly ash pickling liquid are distributed within 0.2% to 8.6%, which indicates that the sample detection deviation is small, the accuracy is high, and the test result reproducibility is good.

[0065] Experiment: Testing actual fly ash pickling liquid.

[0066] Actual fly ash pickling liquid was selected for multiple tests on XRF to verify its reproducibility, and then the results were retested on ICP-MS for comparison. The test results of the two methods are listed in Table 5.

[0067] Table 5: Test results of heavy metal content in fly ash pickling liquid using two detection methods.

[0068]

[0069] From the results in Table 5, it can be seen that the relative deviation of the test results of the actual fly ash pickling solution standard sample and the error of the comparison ICP method are both within 10%, indicating that the accuracy and sample reproducibility of this method are good. In Table 5, YC-1, YC-2, SC-1, and SC-2 are the actual sample numbers of fly ash pickling solution.

[0070] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for rapid detection of heavy metal content in fly ash pickling liquid, characterized in that: The method comprises the following steps: S1. Determine the main heavy metal elements in the fly ash pickling solution according to the energy spectrum of the fly ash pickling solution, and prepare a simulated fly ash pickling solution; S2. Perform ICP testing on the simulated fly ash pickling solution to determine the standard value; S3. According to the standard value, a simulated fly ash pickling solution with a gradient concentration is prepared, XRF detection is performed, and a standard curve is drawn; S4. Use XRF method to detect the fly ash pickling liquid sample to be tested.

2. The method according to claim 1, characterized in that In S1, the main heavy metal elements in the ash pickling solution include: chromium, copper, zinc, cadmium, manganese, and iron.

3. The method according to claim 1, characterized in that In S1, the method for preparing the simulated fly ash pickling solution includes: mixing potassium chromate, copper sulfate, zinc sulfate, cadmium sulfate, manganese sulfate, ammonium ferrous acid and simulated base fly ash in a mass ratio of 3.73:3.93:4.40:2.28:3.08:4.98:77.6, and adding hydrochloric acid to dissolve.

4. The method according to claim 3, characterized in that The components of the base include calcium carbonate, calcium chloride, calcium hydroxide, sodium chloride and potassium chloride; the mass ratio of the calcium carbonate, calcium chloride, calcium hydroxide, sodium chloride and potassium chloride is 8-10:1:1-2:0.6-1:0.6-1.

5. The method according to claim 1, characterized in that In S3, The XRF detection standard curve of chromium content is: y = 0.9999x + 0.0173; The XRF detection standard curve of manganese content is: y = 0.9921x + 0.7409; The XRF detection standard curve for iron content is: y = 0.9922x + 0.7595; The XRF detection standard curve for copper content is: y = 0.995x + 0.8701; The standard curve of zinc content XRF detection is: y = 0.9998x + 0.01782 The XRF detection standard curve of cadmium content is: y=1.0077x-5.3606.

6. The method according to claim 1, characterized in that In S4, the fly ash pickling liquid sample to be tested is filtered through a syringe needle filter membrane, placed in an XRF sample cup, fully wrapped with a polycarbonate film, and small holes are pierced on the surface to ensure that the pressure in the sample cup is equal to the atmospheric pressure.

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