Method for determining arsenic content in copper concentrate by combining microwave digestion with liquid-phase atomic fluorescence

Abstract

The invention discloses a method for determining the arsenic content in copper concentrate by combining microwave digestion and liquid phase atomic fluorescence, and relates to the technical field of determination of the arsenic content in ore, the method comprises the following steps: uniformly mixing a copper concentrate sample with nitric acid, hydrochloric acid and hydrofluoric acid, and carrying out microwave digestion pretreatment; preparing a standard working solution from the arsenite-arsenate standard working solution and a salpeter solution, injecting the standard working solution into a liquid-phase tandem atomic fluorescence spectrophotometer, and drawing a standard curve from the concentrations of As < 3 + > and As < 5 + > and corresponding peak areas; injecting into a liquid-phase tandem atomic fluorescence spectrophotometer for analysis to obtain a chromatogram, and determining the nature by retention time; and calculating the total inorganic arsenic content. According to the method, the microwave digestion pretreatment of the copper concentrate sample does not cause volatilization loss of arsenic element and does not damage the original valence state of arsenic in the sample; the digestion is complete, so that the determination result is accurate; the contents of trivalent arsenic and pentavalent arsenic in a copper concentrate sample are measured by adopting a liquid chromatography-atomic fluorescence tandem mode, and accurate, rapid and convenient quantification is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of the determination of arsenic content in ores, and particularly relates to a method for determining the arsenic content in copper concentrates by combining microwave digestion and liquid-phase atomic fluorescence. Background Art

[0002] Arsenic and its compounds are one of the key monitored pollutants recognized internationally. The toxicity of arsenic is highly related to the valence state of arsenic. The toxicity of trivalent arsenic is about 60 times that of pentavalent arsenic. In the copper smelting industry, the arsenic content in imported copper concentrates shall not be greater than 0.5%. The arsenic content in copper concentrates will have a huge impact on the smelting system. When the arsenic content is too high, it may lead to problems such as an increase in high-arsenic return materials, occupation of production capacity, excessive arsenic in anode plates, and poor quality of cathode copper. During the high-temperature smelting process, the arsenides in copper concentrates will undergo decomposition and oxidation reactions. Therefore, the analysis and determination of the content of arsenides with different valence states in copper concentrates are of great significance for the environmental protection of copper smelting.

[0003] Before the determination of the arsenic content in copper concentrates, it is usually necessary to carry out digestion treatment on the copper concentrate sample. The method is to add acid and then heat and dissolve it on an electric hot plate; or add sodium hydroxide to the sample and perform alkali fusion in a high-temperature muffle furnace, and then leach it with acid. The problems existing in the treatment by using the electric hot plate digestion or alkali fusion method are that due to the high temperature during the dissolution process, trivalent arsenite can be oxidized to pentavalent arsenate, resulting in inaccurate quantitative determination. Summary of the Invention

[0004] To solve the above technical problems, the present invention discloses a method for determining the arsenic valence state in copper concentrates by combining microwave digestion and liquid-phase atomic fluorescence. First, mix the copper concentrate sample with hydrochloric acid, nitric acid, and hydrofluoric acid, and perform microwave digestion pretreatment at 90 °C. Since the digestion temperature is low, it will not cause the volatilization loss of arsenic elements, nor will it destroy the original valence state of arsenic in the sample; at the same time, the sample is completely digested, making the determination result accurate; there is no need to drive off the acid. Use a hydrofluoric acid-resistant injection system and the method of liquid chromatography tandem atomic fluorescence to determine the contents of trivalent arsenic and pentavalent arsenic in the copper concentrate sample.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The method for determining the arsenic content in copper concentrates by combining microwave digestion and liquid-phase atomic fluorescence specifically includes the following steps:

[0007] Step 1, first mix the copper concentrate sample with nitric acid, hydrochloric acid, and hydrofluoric acid in a digestion tank, perform microwave digestion pretreatment. After the temperature of the digestion tank reaches room temperature, remove the digestion tank. There is no need to drive off the acid. Transfer the sample solution in the digestion tank to a plastic volumetric flask, make up the volume and mix well to obtain the test copper concentrate sample solution;

[0008] Step 2: Prepare an arsenite standard stock solution and an arsenate standard stock solution respectively, and then prepare a standard working solution of arsenite-arsenate.

[0009] Step 3: Further prepare standard working solutions with different concentrations by mixing the standard working solution of arsenite-arsenate with a nitric acid solution. Inject the standard working solutions into a liquid-phase tandem atomic fluorescence spectrophotometer respectively. Plot a standard curve by taking the concentrations of As 3+ and As 5+ in the standard working solutions against their corresponding peak areas.

[0010] Step 4: For the test copper concentrate sample solution obtained in Step 1, aspirate the test copper concentrate sample solution and inject it into a liquid-phase tandem atomic fluorescence spectrophotometer for analysis to obtain a chromatogram, and identify it by retention time.

[0011] Step 5: Obtain the contents of As 3+ and As 5+ in the sample solution according to the standard curve, calculate the total inorganic arsenic content, and the number of parallel determinations is not less than two.

[0012] Furthermore, in Step 1, the process of microwave digestion pretreatment is as follows:

[0013] Weigh 0.2 g of the copper concentrate sample (accurate to 0.0001 g) dried at 100 °C - 105 °C for 1 h, place it in a digestion tank, add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid. After mixing evenly, load it into the digestion tank for digestion for 90 min, cool it, and make the volume up to 100 mL in a plastic volumetric flask and mix well. After the solution is filtered through a 0.45-μm disposable microporous filter head, it becomes the test copper concentrate sample solution.

[0014] Meanwhile, perform a blank test. In the digestion tank, only add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid. After mixing evenly, load it into the digestion tank for digestion for 90 min, cool it, and make the volume up to 100 mL in a plastic volumetric flask and mix well. After the solution is filtered through a 0.45-μm disposable microporous filter head, it becomes the test blank sample solution.

[0015] Furthermore, the mass of the copper concentrate sample is accurate to 0.0001 g, and the particle size is less than 0.082 mm. The digestion conditions are as follows: the maximum power of the microwave digestion instrument is 800 W, the power ratio is 100%, the programmed temperature rise time is 20 min, the digestion temperature is 90 °C, and the holding time is 90 min.

[0016] Furthermore, in Step 3, an anion exchange chromatographic column is selected, with a column length of 250 mm and an inner diameter of 4 mm.

[0017] Mobile phase composition: 15 mmol / L ammonium dihydrogen phosphate solution, pH 6.0. The mobile phase elution mode is isocratic elution, and the mobile phase flow rate is 1.0 mL / min, the injection volume is 100 μL, and the injection mode is auto-injection.

[0018] Further, in step 4, the atomic fluorescence parameter conditions are: negative high voltage 300 V, total current of arsenic lamp 90 mA, main current / auxiliary current 60 / 30;

[0019] The atomization method is: flame atomizer;

[0020] The atomization temperature is: medium temperature;

[0021] The height of the atomizer is: 8 mm.

[0022] Carrier solution: 20% hydrochloric acid solution, flow rate 4.0 mL / min;

[0023] Reducing agent: 30 g / L potassium borohydride solution, flow rate 4.0 mL / min;

[0024] Carrier gas flow rate: 400 mL / min;

[0025] Shielding gas flow rate: 900 mL / min.

[0026] Further, the concentrations of both the arsenite standard stock solution and the arsenate standard stock solution are 100 mg / L in terms of As content; the concentration of the arsenite-arsenate standard working solution is 1.00 mg / L in terms of As content.

[0027] Further, in step 5, the total inorganic arsenic content is the sum of As 3+ and As 5+ contents. The inorganic arsenic content in the sample is calculated by the following formula:

[0028]

[0029] In the formula:

[0030] X: the inorganic arsenic content in the sample, unit is milligram per kilogram (mg / kg);

[0031] C0: the concentration of inorganic arsenic compounds in the blank solution, unit is microgram per liter (μg / L);

[0032] C: the concentration of inorganic arsenic compounds in the measured solution, unit is microgram per liter (μg / L);

[0033] V: the volume of sample constant volume, unit is milliliter (mL);

[0034] m: the mass of the sample, unit is gram (g);

[0035] 1000: Conversion factor.

[0036] X3 = X1 + X2

[0037] In the formula:

[0038] X3: Content of total inorganic arsenic in the sample, unit is milligram per kilogram (mg / kg);

[0039] X1: Content of trivalent arsenic in the sample, unit is milligram per kilogram (mg / kg);

[0040] X2: Content of pentavalent arsenic in the sample, unit is milligram per kilogram (mg / kg).

[0041] The beneficial effects of the present invention are as follows. Compared with the prior art, in this method, first, the copper concentrate sample is mixed with hydrochloric acid, nitric acid, and hydrofluoric acid, and microwave digestion pretreatment is carried out at 90 °C. Since the digestion temperature is low, it will not cause the volatilization loss of arsenic elements, nor will it destroy the original valence state of arsenic in the sample; at the same time, the sample is completely digested, making the measurement result more accurate; using a hydrofluoric acid-resistant injection system and the method of liquid chromatography tandem atomic fluorescence to measure the contents of trivalent arsenic and pentavalent arsenic in the copper concentrate sample, the purpose of accurately quantifying arsenic is achieved.

[0042] It has the following characteristics:

[0043] 1. Ensure production safety and product quality

[0044] Arsenic will affect the quality of copper products. Measuring the content of total inorganic arsenic can help enterprises control the production process and ensure that the purity and quality of the final copper products meet the quality standards.

[0045] Since arsenite is more mobile and toxic than arsenate, accurately measuring the contents of trivalent arsenic and pentavalent arsenic in copper concentrate can enable enterprises to take measures in advance to control the entry of high-arsenic materials into production, prevent the arsenic content in the final cathode copper products from being too high, and will not have an adverse impact on the high contents of trivalent arsenic and pentavalent arsenic in the products of downstream industries.

[0046] 2. Contribute to environmental protection and resource utilization

[0047] Accurately measuring the arsenic content can enable enterprises to reasonably handle arsenic-containing waste. Clarifying the valence state and content of arsenic in copper concentrate is beneficial to developing targeted processes, realizing the effective recovery and utilization of associated resources such as arsenic, and improving resource utilization rate.

[0048] 3. Improve the technical level and market competitiveness of the industry

[0049] The invention of a new measurement method can provide technical support for research in related fields, promote the development of disciplines such as analytical chemistry, and provide ideas and methods for the determination of other similar substances. The technology for accurately measuring the arsenic content can improve the market recognition and competitiveness of enterprise products. Description of the Drawings

[0050] Figure 1 For As in the embodiments of the present invention 3+ Linear relationship diagram of the working curve;

[0051] Figure 2 For As in the embodiments of the present invention 5+ Linear relationship diagram of the working curve;

[0052] Figure 3 The standard superposition spectrogram obtained in the embodiments of the present invention. Detailed Embodiments

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0054] The present invention discloses a method for determining the arsenic valence state in copper concentrate by combining microwave digestion and liquid-phase atomic fluorescence. The specific process is as follows:

[0055] (1) First, mix the copper concentrate sample with nitric acid, hydrochloric acid, and hydrofluoric acid in a digestion tank and perform microwave digestion pretreatment.

[0056] Process of microwave digestion pretreatment:

[0057] Weigh 0.2 g of the copper concentrate sample dried at 100 °C - 105 °C for 1 h, accurate to 0.0001 g. Place it in a digestion tank, add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid. After mixing, load it into the digestion tank and digest for 90 min. Cool it down and make the volume up to 100 mL in a plastic volumetric flask, then mix well. The solution is filtered through a 0.45 μm disposable microporous filter head and ready for determination;

[0058] At the same time, conduct a blank test. In the digestion tank, only add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid. After mixing, load it into the digestion tank and digest for 90 min. Cool it down and make the volume up to 100 mL in a plastic volumetric flask, then mix well. The solution is filtered through a 0.45 μm disposable microporous filter head and ready for determination.

[0059] The digestion conditions are as follows: the maximum power of the microwave digester is 800 W, the power ratio is 100%, the programmed temperature rise time is 20 min, the digestion temperature is 90 °C, and the holding time is 90 min. After digestion, wait for the temperature of the digestion tank to reach room temperature, remove the digestion tank, transfer the sample solution in the digestion tank to a 100 mL plastic volumetric flask, make up the volume and mix well. This solution is the sample solution to be measured.

[0060] (2) Prepare arsenite standard stock solution and arsenate standard stock solution respectively, and then prepare the standard working solution of arsenite-arsenate.

[0061] The concentration of the arsenite standard stock solution is 100 mg / L in terms of As content. Select arsenic trioxide (As2O3) standard sample with a purity of ≥99.5%. Accurately weigh 0.0132 g of arsenic trioxide, add 1 mL of 100 g / L potassium hydroxide solution and a small amount of water to dissolve it, transfer it to a 100 mL volumetric flask, add an appropriate amount of hydrochloric acid solution to adjust its acidity to near neutral, and dilute it with water to the scale to prepare the arsenite standard stock solution. Store it at 4 °C for a storage period of one year. Or directly purchase the standard solution material certified by the state and issued with a standard substance certificate.

[0062] The concentration of the arsenate standard stock solution is 100 mg / L in terms of As content. Potassium dihydrogen arsenate (KH2AsO4) standard sample with a purity of ≥99.5%. Accurately weigh 0.0240 g of potassium dihydrogen arsenate, dissolve it in water, transfer it to a 100 mL volumetric flask, and dilute it with water to the scale to prepare the arsenate standard stock solution. Store it at 4 °C for a storage period of one year. Or purchase the standard solution material certified by the state and issued with a standard substance certificate.

[0063] The concentration of the standard working solution of arsenite-arsenate is 1.00 mg / L in terms of As content. Accurately pipette 1.0 mL of arsenite standard stock solution and 1.0 mL of arsenate standard stock solution into a 100 mL volumetric flask respectively, dilute it with water and make up the volume to the scale to obtain the standard working solution of arsenite-arsenate, which is prepared and used immediately.

[0064] (3) Further prepare standard working solutions with different concentrations by mixing the standard working solution of arsenite-arsenate with nitric acid solution. Inject the standard working solutions into the liquid-phase tandem atomic fluorescence spectrophotometer, and plot the standard curve with the concentrations of As 3+ and As 3+ in the standard working solutions and the corresponding peak areas.

[0065] (4) Select an anion exchange chromatographic column with a column length of 250 mm and an inner diameter of 4 mm.

[0066] Mobile phase composition: 15 mmol / L ammonium dihydrogen phosphate solution, pH 6.0. The mobile phase elution mode is isocratic elution, and the mobile phase flow rate is 1.0 mL / min, the injection volume is 100 μL, and the injection mode is auto-injection.

[0067] Take the above-mentioned standard use solution of arsenite-arsenate at 1.00 mg / L, 0.00 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, and 5.00 mL are respectively placed in 6 100-mL volumetric flasks, and diluted with 0.15 mol / L nitric acid solution to prepare a mixed gradient standard working curve of 0.00 μg / L, 10.00 μg / L, 20.00 μg / L, 30.00 μg / L, 40.00 μg / L, and 50.00 μg / L. Inject the mixed gradient standard working curve into the liquid chromatography-tandem atomic fluorescence spectrometer by auto-injection. As 3+ At 2.580 min, As 5+ There is the highest integral response at 6.794 min, and draw the calibration curve of As 3+ and As 5+ That is, the calibration curve of each gradient concentration and the corresponding peak area are shown in Table 1.

[0068] Table 1 Calibration curve table

[0069]

[0070]

[0071] As Figure 1 , Figure 2 , Figure 3 shown, Figure 1 The component name in is As 3+ , the retention time is: 2.580 min, and the linear relationship is: Y = 261.157X - 116.019, R = 0.999378.

[0072] Figure 2 The component name in is As 5+ , the retention time is: 6.974 min, and the linear relationship is: Y = 120.705X + 59.6657, R = 0.999721.

[0073] Standard sample 1: 10.00 μg / L, standard sample 2: 20.00 μg / L, standard sample 3: 30.00 μg / L, standard sample 4: 40.00 μg / L, standard sample 5: 50.00 μg / L of As 3+ , As 5+ The superimposed graph of the peak fitting of the mixed standard curve is shown in Figure 3 .

[0074] (4) The test sample solution is injected into a liquid chromatography-tandem atomic fluorescence spectrometer by an automatic sampling system for analysis to obtain a chromatogram. Qualitative analysis is performed based on the retention time, and the content of As in the test solution is obtained according to the standard curve. The total inorganic arsenic content is calculated. The number of parallel determinations is not less than two. The analysis results of the copper concentrate samples are shown in Table 2. 3+ 、As 5+ content, and the total inorganic arsenic content is calculated. The number of parallel determinations is not less than two. The analysis results of the copper concentrate samples are shown in Table 2.

[0075] The atomic fluorescence parameter conditions are as follows: negative high voltage 300V, total current of arsenic lamp 90mA, main current / auxiliary current 60 / 30.

[0076] The atomization method is: flame atomizer;

[0077] The atomization temperature is: medium temperature;

[0078] The height of the atomizer is: 8mm.

[0079] Carrier liquid: 20% hydrochloric acid solution, flow rate 4.0 mL / min;

[0080] Reducing agent: 30 g / L potassium borohydride solution, flow rate 4.0 mL / min;

[0081] Carrier gas flow rate: 400 mL / min;

[0082] Shielding gas flow rate: 900 mL / min.

[0083] (5) The total inorganic arsenic content is the sum of the contents of As 3+ and As 5+ The inorganic arsenic content in the sample is calculated according to the following formula:

[0084]

[0085] In the formula:

[0086] X: The content of inorganic arsenic in the sample, unit is milligram per kilogram (mg / kg);

[0087] C0: The concentration of inorganic arsenic compounds in the blank solution, unit is microgram per liter (μg / L);

[0088] C: The concentration of inorganic arsenic compounds in the measured solution, unit is microgram per liter (μg / L);

[0089] V: The volume of sample constant volume, unit is milliliter (mL);

[0090] m: The mass of the sample, unit is gram (g);

[0091] 1000: Conversion factor.

[0092] X3 = X1 + X2

[0093] Where:

[0094] X3: The content of total inorganic arsenic in the sample, in milligrams per kilogram (mg / kg);

[0095] X1: The content of trivalent arsenic in the sample, in milligrams per kilogram (mg / kg);

[0096] X2: The content of pentavalent arsenic in the sample, in milligrams per kilogram (mg / kg).

[0097] The calculation result is retained to two significant figures, and the measurement results are shown in Table 2.

[0098] Table 2 Analysis Results of Copper Concentrate Samples

[0099]

[0100] To verify the accuracy of the measurement results, two kinds of arsenate and arsenite standard solutions with the following two concentrations were purchased from the National Research Center for Certified Reference Materials for synchronous experiments:

[0101] Arsenite As 3+ : Concentration 75.7 μg / mL;

[0102] Arsenate As 5+ : Concentration 17.5 μg / mL.

[0103] Use a pipette gun to take 0.1 mL of each of the above standard solutions into the same digestion tank, add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid, mix well and then load into the digestion tank for digestion. The digestion conditions are the same as those of the copper concentrate sample. After digestion, wait for the temperature of the digestion tank to reach room temperature, remove the digestion tank, transfer the solution in the digestion tank to a 100 mL volumetric flask, make up the volume and mix well. The solution is filtered through a 0.45 μm disposable microporous filter head and then injected into a liquid-phase tandem atomic fluorescence spectrophotometer for analysis to obtain a chromatogram. Qualitative analysis is carried out based on the retention time, and according to the standard curve, the concentrations of As 3+ 、As 5+ in the sample solution are 75.5 μg / L and 17.3 μg / L, and the recovery rates are 99.73% and 98.86%, respectively, proving that the accuracy of this analysis method is reliable.

[0104] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for determining the arsenic content in copper concentrate by microwave digestion-liquid phase atomic fluorescence, characterized in that, Specifically, it includes the following steps: Step 1: First, mix the copper concentrate sample with nitric acid, hydrochloric acid, and hydrofluoric acid in a digestion tank, and perform microwave digestion pretreatment. After the temperature of the digestion tank reaches room temperature, remove the digestion tank without acid expulsion. Transfer the sample solution in the digestion tank to a plastic volumetric flask, make up the volume and mix well to obtain the copper concentrate sample solution to be measured; Step 2: Prepare the arsenite standard stock solution and arsenate standard stock solution respectively, and then prepare the standard working solution of arsenite - arsenate; Step 3: Prepare standard working solutions with different concentrations by mixing the standard use solution of arsenite-arsenate with nitric acid solution. Inject the standard working solutions into a liquid-phase tandem atomic fluorescence spectrophotometer respectively, and plot a standard curve with the concentrations of As 3+ and As 5+ in the standard working solutions against their corresponding peak areas; Step 4: For the copper concentrate sample solution to be measured obtained in Step 1, aspirate the copper concentrate sample solution to be measured and inject it into a liquid - phase tandem atomic fluorescence spectrometer for analysis to obtain a chromatogram, and identify it by retention time; Step 5: Obtain the contents of As 3+ and As 5+ in the test sample solution according to the standard curve, calculate the total inorganic arsenic content, and the number of parallel determinations shall be no less than two times.

2. The method for determining the arsenic content in copper concentrate by microwave digestion - liquid phase atomic fluorescence combination according to claim 1, characterized in that, In Step 1, the process of microwave digestion pretreatment: Weigh 0.2 g of the copper concentrate sample dried at 100 °C - 105 °C for 1 h, place it in a digestion tank, add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid. After mixing, load it into the digestion tank for digestion for 90 min, cool it, make up the volume to 100 mL in a plastic volumetric flask, and mix well; after the solution is filtered through a 0.45 - um disposable microporous filter head, it is the copper concentrate sample solution to be measured; At the same time, perform a blank test. In the digestion tank, only add 2.5 mL of nitric acid, 2.5 mL of hydrochloric acid, and 2.5 mL of hydrofluoric acid. After mixing, load it into the digestion tank for digestion for 90 min, cool it, make up the volume to 100 mL in a plastic volumetric flask, and mix well; after the solution is filtered through a 0.45 - um disposable microporous filter head, it is the blank sample solution to be measured.

3. The method for determining the arsenic content in copper concentrate by microwave digestion-liquid phase atomic fluorescence combination according to claim 2, characterized in that, The mass of the copper concentrate sample is accurate to 0.0001 g, and the particle size is less than 0.082 mm; The digestion conditions are: the maximum power of the microwave digestion instrument is 800 W, the power ratio is 100%, the programmed temperature - rising time is 20 min, the digestion temperature is 90 °C, and the holding time is 90 min.

4. The method for determining the arsenic content in copper concentrate by microwave digestion-liquid phase atomic fluorescence combination according to claim 3, characterized in that, In Step 3, an anion - exchange chromatographic column is selected, with a column length of 250 mm and an inner diameter of 4 mm; The composition of the mobile phase: 15 mmol / L ammonium dihydrogen phosphate solution, pH value 6.0; The elution mode of the mobile phase is isocratic elution, the flow rate of the mobile phase: 1.0 mL / min, the injection volume: 100 μL; the injection mode: automatic injection.

5. The method for determining the arsenic content in copper concentrate by microwave digestion-liquid phase atomic fluorescence combination according to claim 4, characterized in that, In Step 4, the atomic fluorescence parameter conditions are: negative high voltage 300 V, total current of the arsenic lamp 90 mA, main current / auxiliary current 60 / 30; The atomization method is: flame atomizer; The atomization temperature is: medium temperature; The height of the atomizer is: 8 mm. Carrier liquid: 20% hydrochloric acid solution, flow rate 4.0 mL / min; Reducing agent: 30 g / L potassium borohydride solution, flow rate 4.0 mL / min; Carrier gas flow rate: 400 mL / min; Shielding gas flow rate: 900 mL / min.

6. The method for determining the arsenic content in copper concentrate by microwave digestion - liquid phase atomic fluorescence combination according to claim 5, characterized in that, The concentrations of the arsenite standard stock solution and arsenate standard stock solution are both 100 mg / L, calculated as As content; the concentration of the standard working solution of arsenite - arsenate is 1.00 mg / L, calculated as As content.

7. The method for determining the arsenic content in copper concentrate by microwave digestion - liquid phase atomic fluorescence binding according to claim 6, characterized in that, In Step 5, the total inorganic arsenic content is the sum of As 3+ and As 5+ contents. The inorganic arsenic content in the sample is calculated according to the following formula: Where: X: The content of inorganic arsenic in the sample, unit: milligram per kilogram (mg / kg); C0: The concentration of inorganic arsenic compounds in the blank solution, unit: microgram per liter (μg / L); C: The concentration of inorganic arsenic compounds in the solution, in micrograms per liter (μg / L); V: The volume of the sample after volume fixation, in milliliters (mL); m: The mass of the sample, in grams (g); 1000: Conversion factor. X3 = X1 + X2 Where: X3: The content of total inorganic arsenic in the sample, in milligrams per kilogram (mg / kg); X1: The content of trivalent arsenic in the sample, in milligrams per kilogram (mg / kg); X2: The content of pentavalent arsenic in the sample, in milligrams per kilogram (mg / kg).

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