Method for measuring chromium content in laterite-nickel ore

Abstract

The present invention relates to the technical field of detection and analysis. Disclosed is a method for measuring the chromium content in laterite-nickel ore. In the present invention, a standard addition method is used, that is, a matrix in a standard solution is similar to a sample matrix, and analysis parameters are reasonably selected, so that matrix effects of easily ionized elements and other elements can be suppressed or eliminated. That is, laterite-nickel ore is digested by using a simple, efficient and low-cost method integrating sodium peroxide alkali fusion, hot water leaching, and hydrochloric acid dissolution, and the ionization interference of ICP-OES is reduced by the standard addition method, so that current research and development requirements are met, and a fast and simple method is provided for subsequent batch testing.

Description

A method for detecting chromium content in laterite nickel ore Technical Field

[0001] This article relates to the field of detection and analysis technology, and specifically to a method for detecting the chromium content in laterite nickel ore. Background Art

[0002] my country's new energy electric vehicle industry is developing rapidly, driving increasing demand for power batteries and, consequently, for cathode materials. Among ternary cathode materials, nickel represents the greatest demand. Currently, nickel is primarily sourced from discarded batteries and nickel ore. Extracting nickel from laterite nickel ore is a key research area. Chromium, an impurity in laterite nickel ore, needs to be reduced to a certain level. Accurately measuring chromium in laterite nickel ore is crucial for mineral processing.

[0003] Due to its stable nature, laterite nickel ore is difficult to completely digest using a single acid or a mixture of acids under plate heating or microwave conditions. The main residual elements are chromium and aluminum. Therefore, the filtrate cannot be filtered and tested. The sample must be completely digested to completely transfer the chromium into solution for testing. Currently, there are three standards for testing chromium content in laterite nickel ore: "SNT 2763.5-2013 Chemical Analysis Methods for Laterite Nickel Ores - Part 5: Determination of Copper, Zinc, and Chromium Contents - Flame Atomic Absorption Spectrometry"; "SNT 2763.6-2014 Chemical Analysis Methods for Laterite Nickel Ores - Part 6: Determination of Nickel, Calcium, Titanium, Manganese, Copper, Chromium, Zinc, and Phosphorus Contents - Inductively Coupled Plasma Atomic Emission Spectrometry"; and "YST 820.21-2013 Chemical Analysis Methods for Laterite Nickel Ores - Part 21: Determination of Chromium Content - Ammonium Ferrous Sulfate Titration Method."

[0004] The digestion approach used in SN T 2763.5-2013 and SNT 2763.6-2014 involves low-temperature digestion with hydrochloric acid, nitric acid, or other acids, followed by filtration to obtain a main solution. The filter residue is then incinerated and digested on a hot plate with sulfuric acid or hydrofluoric acid. Potassium pyrosulfate is then added for incineration. After incineration, hydrochloric acid is added and heated to dissolve the molten material. After evaporation and removal of the acid, the material is combined with the main solution and diluted for analysis using AAS or ICP-OES. The digestion method used in YST 820.21-2013 involves first heating and calcining the sample with sodium peroxide, then melting it in a high-temperature furnace. After incineration, hot water is added for leaching, followed by addition of excess sulfuric acid to dissolve the precipitate. Finally, phosphoric acid is added and heated to decompose the hydrogen peroxide. Both of these digestion methods suffer from complex digestion procedures, lengthy processing times, high reagent usage, and high costs, making them unsuitable for batch testing.

[0005] Inductively coupled plasma atomic emission spectrometry (ICP-AES) is a spectral analysis method that uses inductively coupled plasma as the excitation light source. It has the advantages of high accuracy and precision, low detection limit, rapid determination, wide linear range, and the ability to simultaneously determine multiple elements. It has been widely used abroad for the determination of dozens of elements in environmental samples and samples such as rocks, minerals, and metals.

[0006] Summary of the Invention

[0007] The purpose of this paper is to overcome the shortcomings of the existing technology and provide a method for detecting the chromium content in laterite nickel ore, which realizes accurate and stable detection of the chromium content in laterite nickel ore.

[0008] To achieve the above objectives, the technical solutions adopted in this paper are:

[0009] A method for detecting chromium content in laterite nickel ore comprises the following steps:

[0010] The nickel laterite ore and sodium peroxide are uniformly mixed, roasted, the roasted product is immersed in water for reaction, washed, and then a hydrochloric acid solution is added to obtain a nickel laterite ore digestion solution;

[0011] Diluting the laterite nickel ore digestion solution to obtain a test solution;

[0012] Adding chromium standard solutions to the laterite nickel ore digestion solutions respectively to prepare chromium standard curve solutions with chromium concentrations of A mg / L, A+1 mg / L, A+2 mg / L, A+3 mg / L, and A+4 mg / L;

[0013] The chromium standard curve solutions are respectively introduced into an inductively coupled plasma emission spectrometer for measurement, and a chromium standard working curve is drawn with the concentration of the chromium standard curve solution as the abscissa and the relative intensity of the chromium spectrum emission as the ordinate;

[0014] The test solution is introduced into an inductively coupled plasma emission spectrometer to measure the spectral intensity of the test solution, and the chromium content in the laterite nickel ore is determined according to the chromium standard working curve;

[0015] Where 0≤A≤10.

[0016] This paper uses the standard addition method, that is, making the matrix in the standard solution similar to the sample matrix, and reasonably selecting the analytical parameters to suppress or eliminate the matrix effect of easily ionized elements and other elements; that is, using sodium peroxide alkali fusion + hot water leaching + hydrochloric acid dissolution as a simple, efficient and low-cost method to digest laterite nickel ore, and the standard addition method to reduce the ionization interference of ICP-OES, which meets the needs of current research and development and provides a fast and relatively simple method for subsequent batch testing.

[0017] This method eliminates the need for extensive acid digestion; instead, sodium peroxide and hydrochloric acid are used to completely digest the sample. This method addresses the current analytical standard's complex digestion procedures, the numerous reagent types and dosages required, and the high cost. It also achieves rapid digestion of laterite nickel ore samples.

[0018] The sample solution after sodium peroxide digestion contains a large amount of sodium ions. Directly testing with an ICP-OES would result in significant ionization interference. The method described here incorporates the sample into the standard solution, ensuring that the matrix of the standard solution and the sample are consistent, thereby offsetting ionization interference and other matrix interferences. This prepared standard solution can be used to test samples with similar matrices. This method enables accurate and stable determination of chromium content in laterite nickel ore.

[0019] Where A represents the sample concentration.

[0020] The detection method in this article has a linear correlation coefficient greater than 99.9%, an instrument detection limit of 0.0081 mg / L, a method detection limit of 0.0101%, a method quantification limit of 0.0403%, a low relative deviation, and accurate and stable test results.

[0021] In one embodiment, the mass ratio of the laterite nickel ore to sodium peroxide is (0.2-0.4):(3-5).

[0022] In one embodiment, the calcination temperature is 500-700°C, and the calcination time is 5-15 minutes. Sample pretreatment employs sodium peroxide calcination and alkali fusion, which can be completed within a relatively short calcination time. After calcination, the sample is leached with hot water and then digested by adding concentrated hydrochloric acid and heating on a flat plate until the solution is clear and transparent.

[0023] In one embodiment, the solid-to-liquid ratio of the laterite nickel ore and the hydrochloric acid solution is (0.2-0.4) g: (20-30) mL.

[0024] In one embodiment, the laterite nickel ore digestion solution is diluted 1 to 100 times.

[0025] In one embodiment, the laterite nickel ore digestion solution is diluted 10 times.

[0026] In one embodiment, the concentration of chromium in the chromium standard solution is 100 mg / L.

[0027] In one embodiment, 1≤A≤10.

[0028] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer include: a radio frequency power of 1100 to 1300W.

[0029] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer include: a radio frequency power of 1150W.

[0030] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer further include: an atomizing gas flow rate of 0.6 to 0.8 L / min, a cooling gas flow rate of 10 to 20 L / min, and an auxiliary gas flow rate of 0.5 to 1.5 L / min.

[0031] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer further include: an atomizing gas flow rate of 0.6 L / min, a cooling gas flow rate of 12.5 L / min, and an auxiliary gas flow rate of 0.5 L / min.

[0032] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer further include: a pump speed of 40 to 50 rpm.

[0033] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer further include: a detection wavelength of 267.716 nm.

[0034] In one embodiment, the operating parameters of the inductively coupled plasma optical emission spectrometer further include: plasma observation is vertical observation, and the observation height is 10 mm.

[0035] By using the analytical parameters described herein, the matrix effects of easily ionizable elements and other elements can be suppressed or eliminated, further improving the accuracy and stability of detection.

[0036] The beneficial effects of this paper are as follows: (1) This paper uses the standard addition method, that is, the matrix in the standard solution is made similar to the sample matrix, and the analysis parameters are reasonably selected to suppress or eliminate the matrix effect of easily ionized elements and other elements; that is, the sodium peroxide alkali fusion + hot water leaching + hydrochloric acid acid dissolution method is used to digest laterite nickel ore. The standard addition method is used to reduce the ionization interference of ICP-OES, which meets the needs of current research and development and provides a fast and simple method for subsequent batch testing; (2) In the determination method of this paper, no large amount of acid digestion is required. Only sodium peroxide and hydrochloric acid are used to completely digest the sample, which solves the problems of cumbersome digestion steps, multiple types of reagent consumption, large amount of reagent consumption, and high cost in the current analytical standards. Rapid digestion of laterite nickel ore samples is achieved; (3) In this paper, there are a large amount of Na ions in the sample solution after sodium peroxide digestion. If it is directly tested by ICP-OES, the high content of Na will cause serious ionization interference. The method described here adds sample to the standard solution to maintain a consistent matrix between the standard solution and the sample, thereby canceling out ionization interference and other matrix interferences. This prepared standard solution can be used to test samples with similar matrices. This method enables accurate and stable determination of chromium content in laterite nickel ore. DETAILED DESCRIPTION

[0037] In order to better illustrate the purpose, technical solutions and advantages of this article, this article will be further described below in conjunction with specific embodiments and comparative examples. The purpose is to understand the content of this article in detail, rather than to limit this article.

[0038] Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this article are commonly used reagents and instruments.

[0039] Example 1

[0040] A method for detecting chromium content in laterite nickel ore comprises the following steps:

[0041] (1) Weigh 1g of sodium peroxide and place it in a 50mL nickel crucible. Then, place 0.2g of laterite nickel ore sample on it. The particle size of the laterite nickel ore sample must be less than 160 microns (pass through a 95-mesh sieve) and dry to constant weight (moisture removal). Then, place 2g of sodium peroxide on it and place it in a muffle furnace. After calcining at 700℃ for 5 minutes, take out the sample and cool it slightly. Place the nickel crucible and the sample in a 250mL beaker, place the crucible on its side, and cover it with a watch glass. Slowly add the pre-heated ultrapure water into the beaker to immerse the crucible. Soak for about 5 minutes until the sodium peroxide and water react completely to form sodium hydroxide. Rinse the sample in the crucible with secondary water, and also rinse the crucible wall. Add 20mL of GR hydrochloric acid to the beaker and heat on a flat heater for about 3 minutes until the solution is clear and transparent to obtain the laterite nickel ore digestion solution.

[0042] (2) diluting the laterite nickel ore digestion solution of step (1) by 10 times to obtain a solution to be tested;

[0043] (3) preparing a chromium standard curve solution: pipetting 10 mL of the solution from the laterite nickel ore digestion solution of step (1) into a 100 mL volumetric flask, pipetting 5 times in parallel, adding 0 mL, 1 mL, 2 mL, 3 mL, and 4 mL of the chromium standard solution to 5 parallel samples, respectively, and calibrating the volume to the scale line with water, shaking well, and obtaining a chromium standard curve solution;

[0044] The concentration of chromium in the chromium standard solution is 100 mg / L;

[0045] The concentrations of the chromium standard curve solutions are shown in Table 1.

[0046] Table 1

[0047] (4) Set the instrument parameters and methods: RF power 1150 W, atomizing gas flow rate 0.6 L / min, cooling gas flow rate 12.5 L / min, auxiliary gas flow rate 0.5 L / min, pump speed 45 rpm, observation height 10 mm. Select wavelength Cr 267.716 nm, vertical observation.

[0048] The chromium standard curve solution obtained in step (3) is sequentially introduced into the inductively coupled plasma emission spectrometer according to the setting method, and the chromium working curve is drawn with the concentration of the chromium standard curve solution as the horizontal axis and the relative intensity of the chromium spectral emission as the vertical axis. The fitting coefficient of the standard curve is ≥0.999.

[0049] (5) The test solution obtained in step (2) is placed in an inductively coupled plasma emission spectrometer to measure the spectral intensity of the sample solution. The concentration of the sample solution is obtained based on the linear relationship between the spectral intensity and the concentration, and the mass percentage of the chromium element is obtained based on the sample weight, the constant volume, and the dilution factor.

[0050] Test results

[0051] The method validation performed in this section refers to GBT 27417-2017 Guidance on Validation and Verification of Chemical Analysis Methods for Conformity Assessment

[0052] (1) The detection limits and linear correlation coefficients used in this study are shown in Table 2. The instrument detection limit, method detection limit, and method quantification limit are calculated as follows:

[0053] Instrument Detection Limit: The lowest concentration or amount of an analyte at which an instrument reliably distinguishes the target analyte signal from the background (noise). The test results in Table 2 are obtained by independently testing the sample blank 11 times, and the standard deviation is calculated. The instrument detection limit is expressed as 3 times the standard deviation.

[0054] Method Detection Limit: The lowest concentration or amount of an analyte that can reliably identify or differentiate the analyte signal from a specific matrix background using a specific method. The test results in Table 2 are obtained by incorporating the instrument detection limit into the fixed volume and sample weight.

[0055] Method quantification limit: The lowest amount of an analyte that can be reliably detected and quantified using a method in a specific matrix with a certain degree of confidence. To increase the credibility of the data, the test results in Table 2 are expressed using four times the method detection limit.

[0056] Table 2 Detection limits and correlation coefficients of spectral lines

[0057] (2) The accuracy of the test results is shown in Tables 3 and 4. Accuracy can be assessed using spiked recovery and reference material. When the content is greater than 0.1%, the recovery is required to be between 95% and 105%.

[0058] Spiked recovery: A laterite nickel ore standard was added to the sample during the weighing process to determine the overall recovery of the method. The mass of the spiked element is generally 0.5-2 times the mass of the element being measured. In this experiment, the mass of the spiked element was approximately 1.4 times the mass of the element being measured.

[0059] Reference material testing: The reference material is tested using the method described in this article and compared with the given standard value. Since the standard sample has no uncertainty, the deviation of the standard sample tested using the method described in this article is expressed by relative deviation.

[0060] When measuring reference materials, the following changes are made to the instrument parameters:

[0061] Test 1: According to the method of Example 1, only the atomizing gas flow rate was changed by 0.7 L / min.

[0062] Test 2: According to the method of Example 1, only the atomizing gas flow rate was changed to 0.8 L / min.

[0063] Test 3: According to the method of Example 1, only the cooling gas flow rate was changed by 10 L / min.

[0064] Test 4: According to the method of Example 1, only the cooling air flow rate was changed by 20 L / min.

[0065] Test 5: According to the method of Example 1, only the auxiliary gas flow rate was changed by 1.0 L / min.

[0066] Test 6: According to the method of Example 1, only the auxiliary gas flow rate was changed to 1.5 L / min.

[0067] Table 3 Test spike recovery

[0068] Table 4 Comparison of standard sample tests

[0069] (3) The precision tested in this paper is shown in Tables 5 and 6. Precision is generally expressed as repeatability and reproducibility, with a content range of 1%-10%, and the coefficient of variation within the laboratory is required to be less than 2%.

[0070] Repeatability test: The sample was digested 6 times in parallel and tested at the same time. Calculate the coefficient of variation

[0071] Reproducibility experiment: The sample was digested 3 times in parallel every day for two consecutive days and tested. Calculate the coefficient of variation

[0072] Table 5 Repeatability test results

[0073] Table 6

[0074] Comparative Example 1

[0075] Laterite nickel ore samples were digested using a plate acid digestion method using hydrochloric acid, nitric acid, hydrofluoric acid, perchloric acid, and sulfuric acid. Specifically, weigh 0.1-0.2 g of sample into a 100 mL polytetrafluoroethylene beaker and add the corresponding acid listed in Table 7. Heat the beaker on a flat electric stove and digest until the acid solution is nearly dry. Record the time taken. Remove the beaker and allow it to cool. Transfer the sample from the beaker to a 100 mL volumetric flask with grade II water to the final volume. Observe the sample after digestion to see if there is any residue and to ensure the solution is clear and transparent. See Table 7 for details.

[0076] Laterite nickel ore samples were digested using microwave acid digestion, using a variety of acids including hydrochloric acid, nitric acid, hydrofluoric acid, and perchloric acid. Specific steps: Weigh 0.1 g of sample into a microwave digestion vessel. Add the corresponding acid in Table 7 and microwave digest according to the protocol. Transfer the sample to a polytetrafluoroethylene beaker and add 1 mL of perchloric acid to drive the digestion until nearly dry. Record the digestion time. Remove the beaker and let it cool. Transfer the sample from the beaker to a 100 mL volumetric flask with grade II water to the final volume. Observe the sample for residue and ensure the solution is clear and transparent after digestion. See Table 7 for details.

[0077] Laterite nickel ore samples were digested using sodium hydroxide alkali fusion followed by hydrochloric acid dissolution. The following steps were used: 0.1 g of sample was weighed into a 30 mL nickel crucible. The crucible was placed in a muffle furnace and calcined at 650°C for 2 h. The crucible was then removed and allowed to cool. An appropriate amount of secondary water was added to the crucible and heated on a flat plate heater until the sodium hydroxide dissolved. The sample was transferred to a 250 mL beaker and digested with 25 mL of hydrochloric acid for 20 min. The sample was then transferred to a 100 mL volumetric flask and brought to volume. After digestion, the sample was observed for residue and clarity of the solution (see Table 7 for details).

[0078] Table 7

[0079] It can be seen from Table 7 that the acid consumption of the flat plate acid dissolution is large, and it cannot be completely digested, the data is low and fluctuates greatly. The microwave acid dissolution method takes a long time and cannot be completely digested, and the data is low. Sodium hydroxide alkali dissolution + hydrochloric acid dissolution takes a long time, and the sample is easy to overflow after burning and is not easy to leach, so the data is low. Sodium peroxide alkali dissolution + hydrochloric acid dissolution takes a short time, the sample is completely digested, and the sample is easy to leach. It can be seen that in the digestion method of this article, there is no need for large-scale acid digestion. Only sodium peroxide and hydrochloric acid can completely digest the sample, which solves the problems of complicated digestion steps, many types of reagent consumption, large dosage, and high cost in the current analysis standard. Rapid digestion of laterite nickel ore samples was achieved.

[0080] Comparative Example 2

[0081] The method of Comparative Example 2 is as follows:

[0082] (1) Weigh 1g of sodium peroxide and place it in a 50mL nickel crucible. Then, place 0.2g of laterite nickel ore sample on it. The particle size of the laterite nickel ore sample must be less than 160 microns (pass through a 95-mesh sieve) and dry to constant weight (moisture removal). Then, place 2g of sodium peroxide on it and place it in a muffle furnace. After calcining at 700℃ for 5 minutes, take out the sample and cool it slightly. Place the nickel crucible and the sample in a 250mL beaker, place the crucible on its side, and cover it with a watch glass. Slowly add the pre-heated ultrapure water into the beaker to immerse the crucible. Soak for about 5 minutes until the sodium peroxide and water react completely to form sodium hydroxide. Rinse the sample in the crucible with secondary water, and also rinse the crucible wall. Add 20mL of GR hydrochloric acid to the beaker and heat on a flat heater for about 3 minutes until the solution is clear and transparent to obtain the laterite nickel ore digestion solution.

[0083] (2) diluting the laterite nickel ore digestion solution of step (1) by 10 times to obtain a solution to be tested;

[0084] (3) Prepare the chromium standard curve solution: add 0 mL, 1 mL, 2 mL, 3 mL, and 4 mL of the chromium standard solution to a 100 mL volumetric flask, dilute to the mark with secondary water, and shake well to obtain the chromium standard curve solution;

[0085] The concentration of chromium in the chromium standard solution is 100 mg / L;

[0086] The concentrations of the chromium standard curve solutions are shown in Table 8.

[0087] Table 8

[0088] (4) Set the instrument parameters and methods: RF power 1150 W, atomizing gas flow rate 0.6 L / min, cooling gas flow rate 12.5 L / min, auxiliary gas flow rate 0.5 L / min, pump speed 45 rpm, observation height 10 mm. Select wavelength Cr267.716 nm, vertical observation.

[0089] The chromium standard curve solution obtained in step (3) is sequentially introduced into the inductively coupled plasma emission spectrometer according to the setting method, and the chromium working curve is drawn with the concentration of the chromium standard curve solution as the horizontal axis and the relative intensity of the chromium spectral emission as the vertical axis. The fitting coefficient of the standard curve is ≥0.999.

[0090] (5) The test solution obtained in step (2) is placed in an inductively coupled plasma emission spectrometer to measure the spectral intensity of the sample solution. The concentration of the sample solution is obtained based on the linear relationship between the spectral intensity and the concentration, and the mass percentage of the chromium element is obtained based on the sample weight, the constant volume, and the dilution factor.

[0091] Table 9 Comparison of test results between standard addition method and standard curve method

[0092] The samples were prepared using the sodium peroxide alkali fusion + hot water leaching + hydrochloric acid dissolution digestion method described herein. A commercially available 100 mg / L chromium standard solution was directly diluted to prepare a chromium test standard solution. A standard curve was plotted and the samples were tested. The results of six sets of repeatability experiments are compared in Table 9. The range and COV of the standard addition method (i.e., the method of Example 1) were less than those of the standard curve method (i.e., the method of Comparative Example 2), indicating minimal test fluctuation.

[0093] Therefore, this paper uses the standard addition method, that is, making the matrix in the standard solution similar to the sample matrix, and reasonably selecting the analysis parameters to suppress or eliminate the matrix effect of easily ionized elements and other elements; that is, using sodium peroxide alkali fusion + hot water leaching + hydrochloric acid dissolution as a simple, efficient and low-cost method to digest laterite nickel ore, and the standard addition method to reduce the ionization interference of ICP-OES, which meets the needs of current research and development and provides a fast and relatively simple method for subsequent batch testing.

Claims

1. A method for detecting chromium content in laterite nickel ore, characterized in that: The following steps are involved: The laterite nickel ore and sodium peroxide are uniformly mixed, roasted, the roasted product is immersed in water for reaction, washed, and then a hydrochloric acid solution is added to obtain a laterite nickel ore digestion solution; Diluting the laterite nickel ore digestion solution to obtain a test solution; Adding chromium standard solutions to the laterite nickel ore digestion solutions respectively to prepare chromium standard curve solutions with chromium concentrations of Amg / L, A+1mg / L, A+2mg / L, A+3mg / L, and A+4mg / L respectively; The chromium standard curve solutions are respectively introduced into an inductively coupled plasma emission spectrometer for measurement, and a chromium standard working curve is drawn with the concentration of the chromium standard curve solution as the abscissa and the relative intensity of the chromium spectrum emission as the ordinate; The test solution is introduced into an inductively coupled plasma emission spectrometer, the spectral intensity of the test solution is measured, and the chromium content in the laterite nickel ore is determined according to the chromium standard working curve; Where 0≤A≤10.

2. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The mass ratio of the laterite nickel ore to sodium peroxide is (0.2-0.4):(3-5).

3. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The calcination temperature is 500-700° C., and the calcination time is 5-15 minutes.

4. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The solid-to-liquid ratio of the laterite nickel ore and the hydrochloric acid solution is (0.2-0.4) g: (20-30) mL.

5. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The dilution multiple of the laterite nickel ore digestion solution is 1 to 100 times.

6. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The dilution multiple of the laterite nickel ore digestion solution is 10 times.

7. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The concentration of chromium in the chromium standard solution is 100 mg / L.

8. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: 1≤ A≤10。 9. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer include: radio frequency power is 1100-1300W.

10. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer include: the radio frequency power is 1150W.

11. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer also include: atomizing gas flow rate of 0.6-0.8 L / min, cooling gas flow rate of 10-20 L / min, and auxiliary gas flow rate of 0.5-1.5 L / min.

12. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer also include: atomizing gas flow rate of 0.6 L / min, cooling gas flow rate of 12.5 L / min, and auxiliary gas flow rate of 0.5 L / min.

13. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer also include: a pump speed of 40 to 50 rpm.

14. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer also include: the detection wavelength is 267.716 nm.

15. The method for detecting chromium content in laterite nickel ore according to claim 1, characterized in that: The working parameters of the inductively coupled plasma emission spectrometer also include: plasma observation is vertical observation, and the observation height is 10 mm.

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