阅读说明：本技术 一种镍铁中多元素的快速连续测定方法 (Method for rapidly and continuously measuring multiple elements in ferronickel ) 是由 王纪华 胡凤萍 孔令军 王万涛 于 2020-11-19 设计创作，主要内容包括：本发明涉及一种镍铁中多元素的快速连续测定方法,针对红土镍矿火法还原熔炼生产镍铁的工艺而提出,包括：从流动的镍铁熔体中直接取样、快速冷却,倒出镍铁样锭；使用金刚石刀片切割制片,厚度为3-4mm；对待测样片中Ni、Fe、Si、Co、Cr、S、P的光谱强度进行测定,并根据预存的标准工作曲线确定各元素的含量。本发明实现了镍铁中各组分的快速测定,40min内即可完成1个样品的多元素或组分的联测,解决了传统方法单元素单方法测定的缺陷,实现主量成分与次量成分的联测。相比较国家标准,节省样品分析时间在4小时以上,检测分析速度快捷,劳动效率高,分析成本低、环境友好操作简便,具有很好的应用前景和很高的实用价值。(The invention relates to a method for rapidly and continuously measuring multiple elements in ferronickel, which is provided for a process for producing the ferronickel by reducing and smelting laterite-nickel ore by a pyrogenic process, and comprises the following steps: directly sampling from the flowing ferronickel melt, rapidly cooling, and pouring out a ferronickel sample ingot; cutting the slices by a diamond blade, wherein the thickness is 3-4 mm; and measuring the spectral intensity of Ni, Fe, Si, Co, Cr, S and P in the sample wafer to be measured, and determining the content of each element according to a pre-stored standard working curve. The invention realizes the rapid determination of each component in the ferronickel, can complete the combined determination of multiple elements or components of 1 sample within 40min, solves the defect of single element single method determination in the traditional method, and realizes the combined determination of major components and minor components. Compared with the national standard, the method saves the sample analysis time by more than 4 hours, has quick detection and analysis speed, high labor efficiency, low analysis cost, environmental protection, simple and convenient operation, and has good application prospect and high practical value.)

1. A method for rapidly and continuously measuring multiple elements in ferronickel is characterized in that the method for measuring the multiple elements in the ferronickel is based on a process for producing the ferronickel by reducing and smelting laterite-nickel ore by a pyrogenic process, and comprises the following steps:

(1) sampling: sampling from the flowing ferronickel melt by using a sampling spoon, pouring into a sampling mold, quickly dipping the sampling mold in water for cooling, and pouring out a nickel-iron sample ingot;

(2) cutting and flaking: slicing the nickel-iron sample ingot on a cutting machine to obtain a sample wafer to be measured, wherein the thickness of the sample wafer to be measured is 3-4mm, and the cutting knife is a diamond blade;

(3) content determination: measuring the spectral intensity of Ni, Fe, Si, Co, Cr, S and P in the sample wafer to be measured by using an X-ray fluorescence spectrometer, and determining the content of each element according to a pre-stored standard working curve of each element; and the standard working curve of each element is obtained by drawing a standard sample after the measurement of a preset content fixed value rule fixed value and corresponding spectral intensity.

2. The method according to claim 1, wherein the predetermined content setting rule of each element is specifically:

ni, measuring range 9.0-14.0%, dimethylglyoxime photometry;

fe, measuring range of 75-85%, and potassium dichromate titration;

si, measuring range of 0.1-7.0%, alkali fusion-acidification silicomolybdenum yellow photometry;

co, measuring range 0.10-0.50%, microwave-plasma emission spectrometry;

cr, measuring range of 0.50-5.00%, microwave-plasma emission spectrometry;

s, measuring range of 0.10-0.25%, C-S analyzer;

p, measuring range of 0.01-0.25%, bismuth nitrate-molybdenum blue spectrophotometry.

3. The method of claim 1, wherein the sampling mold is made of cast iron, and the prepared ferronickel-like ingot is columnar.

4. The assay of claim 1, wherein the sampling scoop is made of high temperature ceramic fiber.

Technical Field

The invention relates to the field of chemical analysis and detection of nickel iron produced by laterite reduction, in particular to a rapid and continuous determination method for multiple elements in nickel iron.

Background

Because the process technology for developing nickel sulfide resources is mature, the development of metallic nickel is mainly based on nickel sulfide resources for a long time, but the reserve of the nickel sulfide resources is sharply reduced due to the exploitation of the nickel sulfide resources for a long time, and in recent 30 years, no major breakthrough is made in the exploration of new nickel sulfide resources, the nickel metallurgy industry taking nickel sulfide as a development object gradually falls into the embarrassment of no pot-in-the-meter, and laterite-nickel ore is undoubtedly a new choice, meanwhile, the iron and steel metallurgy enterprises are driven by the benefit of reducing the production cost of stainless steel products, and the attention is also paid to laterite-nickel ore, so the resource development and utilization of laterite-nickel ore become a new development hotspot in the metallurgy industry. The laterite nickel ore pyrometallurgy reduction smelting process is a development technology of nickel which is developed and applied most rapidly in 5 to 6 years, and the product is coarse-grade ferronickel with the nickel grade of 10 to 15 percent and the iron grade of 75 to 85 percent and is mainly used as a raw material for stainless steel production.

For the content determination of each element (Ni, Fe, Si, Co, Cr, S, P) in ferronickel of different forms for steelmaking and casting, 17 chemical analysis methods are specified in the product standard GB/T25049-2009, and the specific results are shown in the following Table 1:

TABLE 1 chemical analysis method of each element in ferronickel

Remarking: GB/T21931.1 determination of nickel, ferronickel and nickel alloy carbon content-high frequency combustion infrared absorption method; GB/T21933.1 nickel iron nickel content determination-dimethylglyoxime weight method; GB/T21933.2 nickel-iron-silicon content determination-gravimetric method; measuring the content of nickel, iron and cobalt in GB/T21933.3-flame atomic absorption spectrometry; GB/T21931.3 determination of nickel, ferronickel and nickel alloy phosphorus content-phosphorus vanadium molybdenum yellow spectrophotometry; measuring the sulfur content of the nickel, the ferronickel and the nickel alloy by a high-frequency combustion infrared absorption method in GB/T21931.2; GB/T24570 determination of contents of nickel, iron, phosphorus, manganese, chromium, copper, cobalt and silicon-inductively coupled plasma atomic emission spectrometry; GB/T24198 method for measuring contents of nickel, iron, nickel, silicon, phosphorus, manganese, cobalt, chromium and copper by using wavelength dispersion X-ray fluorescence spectrometry (conventional method)

However, the above analysis method has the following disadvantages: the analysis consumes long time, can not meet the process control time limit requirement of pyrometallurgical smelting (within 2 hours), and has the disadvantages of more workers, low efficiency, more types of related chemical reagents and high cost. And the rapid analysis of the components (within 2 hours of time limit) is the requirement of high yield and low consumption of the laterite-nickel ore pyrometallurgical reduction process and the requirement of safe control of the pyrometallurgical furnace process, so the rapid analysis of the ferronickel is very important and necessary.

Disclosure of Invention

The invention aims to solve the technical problem of providing a rapid and continuous determination method for multiple elements in ferronickel, which can realize rapid joint measurement of major components and minor components and effectively shorten the time required by determination.

In order to solve the problems, the invention provides a rapid and continuous determination method of multiple elements in ferronickel, which is based on a process for producing ferronickel by pyrogenic reduction smelting of laterite-nickel ore, and the determination method comprises the following steps:

(1) sampling: sampling from the flowing ferronickel melt by using a sampling spoon, pouring into a sampling mold, quickly dipping the sampling mold in water for cooling, and pouring out a nickel-iron sample ingot;

(2) cutting and flaking: slicing the nickel-iron sample ingot on a cutting machine to obtain a sample wafer to be measured, wherein the thickness of the sample wafer to be measured is 3-4mm, and the cutting knife is a diamond blade;

(3) content determination: measuring the spectral intensity of Ni, Fe, Si, Co, Cr, S and P in the sample wafer to be measured by using an X-ray fluorescence spectrometer, and determining the content of each element according to a pre-stored standard working curve of each element; and the standard working curve of each element is obtained by drawing a standard sample after the measurement of a preset content fixed value rule fixed value and corresponding spectral intensity.

Preferably, the preset content fixed value rule of each element is specifically as follows:

ni, measuring range 9.0-14.0%, dimethylglyoxime photometry;

fe, measuring range of 75-85%, and potassium dichromate titration;

si, measuring range of 0.1-7.0%, alkali fusion-acidification silicomolybdenum yellow photometry;

co, measuring range 0.10-0.50%, microwave-plasma emission spectrometry;

cr, measuring range of 0.50-5.00%, microwave-plasma emission spectrometry;

s, measuring range of 0.10-0.25%, C-S analyzer;

p, measuring range of 0.01-0.25%, bismuth nitrate-molybdenum blue spectrophotometry.

Preferably, the sampling mould is made of cast iron, and the prepared ferronickel-like ingot is columnar.

Preferably, the sampling spoon is made of high temperature ceramic fiber.

Compared with the prior art, the invention has the following advantages:

1. the invention realizes the rapid determination of Ni, Fe, Si, Co, Cr, S and P elements or components in the ferronickel, can complete the joint determination of multiple elements or components of 1 sample within 40min, solves the defect of single element single method determination in the traditional method, and realizes the joint determination of major components and minor components. Compared with the national standard, the invention saves the sample analysis time by more than 4 hours, has rapid detection and analysis speed, high labor efficiency and simple and convenient operation, and has good application prospect and high practical value.

2. The invention adopts a sample preparation mode of melt casting-columnar cutting, has quick sample preparation process, does not need wet dissolution of materials, and saves the sample pretreatment time by more than 2 hours compared with the national standard.

3. The method adopts the method of fast pouring and fast cooling when the melt is sampled, overcomes the phenomena of component segregation possibly generated when the sample is naturally cooled, crystalline lens generation possibly occurring in an internal organization structure and the like, ensures the uniformity of the sample, solves the acknowledged technical problem that the X fluorescence spectrum of the Ni, Fe, Si, Co, Cr, S and P elements in the ferronickel is not linear or has poor linear regression correlation coefficient, and has certain technical advancement.

4. In the invention, when the working curve is drawn, the ferronickel standard sample uses a specific content definite value rule, the obtained measurement result is stable, the reproducibility is good, the method is easy to master, and the linear relation of the W (%) -I (Kcps) working curve obtained according to the method is good.

Detailed Description

Firstly, determining step

The invention provides a complete method for realizing XRF multi-element rapid combined measurement of Ni, Fe, Si, Co, Cr, S and P in ferronickel, which specifically comprises the following steps:

(11) sampling of a sample to be tested

In a ferronickel melt discharging chute of a ferronickel electric furnace, a high-temperature ceramic fiber sampling spoon is used for taking out the ferronickel melt (about 280g) from the flowing ferronickel melt, pouring the ferronickel melt into a sampling mold (made of cast iron), quickly dipping water for cooling, and pouring out a ferronickel sample ingot.

Wherein, the ferronickel melt adopted during sampling must be poured into a mould quickly and then dipped in water quickly for cooling so as to prevent segregation phenomenon possibly caused by slow cooling.

The geometry of this appearance spindle is: a column body with a length of 600mm, an upper part phi 35mm and a lower part phi 33 mm; the sample ingot is put into a sample bag, and a sample mark (sampling time, shift and furnace number) is made on the sample bag and sent into a laboratory for standby.

(12) Cutting of sample to be tested (preparation of sample for fluorescence analysis)

And (3) fixing the sample ingot prepared in the step (11) on bench clamps of an automatic precision cutting machine, wherein a cutting knife is a diamond blade, and cutting to obtain a sample wafer to be measured with the diameter phi of 33mm and the thickness of 3-4 mm.

The ferronickel hardness is in HV 350-HV 460 range, sample ingot cutting parameters of the cutting machine are-adjusting the X-axis moving worktable, so that the thickness of a sample wafer is 3-4mm, the Y advancing speed is set to be 2.0mm/min, the Y stroke is set to be 55mm, the rotating speed of a cutting wheel (the rotating speed of a main motor) is 270 (. 10) revolutions per second, a power switch of a cooling water pump is turned on, an operation key is started, and about 27min is consumed for completing the cutting of one sample wafer.

Theoretically, the corundum (Al2O3) blade can also cut ferronickel ingots, but tests show that when the corundum (Al2O3) blade is adopted, the cutting speed is 2.0mm/min and 1.5mm/min, only 3-4mm can be cut, and the cutting wheel is locked, so that the cutting scheme adopted in the step (12) is the fastest cutting scheme.

The effect of general production process variations on the slicing of sample ingots: low nickel-iron-silicon (< 1.0%) -large melt viscosity, poor flowability, more pores (carbon dust overflowing from the melt), reduced hardness (352HV) -good brightness, good metallic luster of cut sections. The nickel-iron-silicon has high (> 4.5%) viscosity, good fluidity, large hardness (450HV), easy rusting, poor luster of cut section metal and easy rust spot growth.

In practical application, after a sample wafer to be detected is prepared, before the fluorescence spectrometer is used for measuring the content of the sample wafer to be detected, the edge of the sample wafer to be detected needs to be leveled and repaired: and opening a power switch of the grinding wheel sample grinding machine, slightly grinding off cutting burrs at the edge of the sample wafer to be detected on the grinding wheel, cleaning the irradiation surface by using alcohol cotton, and marking for later use.

The main instruments used in this step (12):

automatic precision cutting machine, SYJ-200, Shenyang Kejing Automation Equipment Co., Ltd

Edge-sintered Diamond saw blade, Shenyang Kejing Automation Equipment Co., Ltd

Single disc plane sample grinder, PM-350, automatic control research institute of design research institute of steel company, saddle of liaison.

(13) Content determination of each element in sample to be detected

The spectral intensity of Ni, Fe, Si, Co, Cr, S and P in the sample wafer to be measured is measured by an X-ray fluorescence spectrometer (microwave plasma emission spectrometer, Agilent-4210, Agilent technologies) and the content of each element is determined according to the pre-stored standard working curve of each element.

In practical application, the standard working curve of each element is prestored in the spectrometer, and after the spectral intensity of each element is measured, the content measurement result can be automatically calculated and displayed. Indeed, except where expressly indicated herein, reference may be made to the prior art for specific procedures for performing spectral intensity measurements using fluorescence spectrometers.

The measurement conditions for each element in ferronickel are shown in table 2 below.

TABLE 2 measurement conditions of the elements of ferronickel in the present invention

Selecting and measuring standard samples and drawing standard working curves

In the invention, the standard working curve of each element is obtained by drawing a standard sample after the measurement of a preset content constant value rule (see table 3 below) and corresponding spectral intensity.

TABLE 3 chemical analysis method of chemical components in ferronickel sample in the present invention

The main analytical equipment: microwave plasma emission spectrometer, Agilent-4210, Agilent technologies; carbon sulfur analyzer, CS-i, Ellt, Germany; box resistance furnace, SX2-10-12, Shanghai Ming electric furnace Co., Ltd; UV-VIS Spectrophotometer, ORION AQUAMATE 8000, USA thermoelectric corporation; analytical balance, Sartorius.

In the prior art, when the nickel of a standard sample is subjected to value setting according to a GB/T21933.1 dimethylglyoxime weight method and the silicon of the standard sample is subjected to value setting according to a GB/T21933.2 weight method, the time consumption of the analysis process is long, the stability of the measurement result of the silicon is poor, and the linearity of the drawn XRF working curve is poor. The method is characterized in that the method is applied to the fixed value of the ferronickel standard sample in the table 3, the obtained measurement result is stable, the reproducibility is good, the method is easy to master, and the linear relation of the W (%) -I (Kcps) working curve obtained according to the method is good.

It should be noted that, when silicon in ferronickel is determined by alkali fusion-acidification silicomolybdenum yellow photometry, the yellow color of ferric iron can make the measurement result higher, and the contribution rate of each milligram (mg) of iron in a coexisting system is about 0.004Abs, and the measurement result of the existing method (0.1g of sample, alkali fusion, constant volume in 250mL volumetric flask, and colorimetric after taking 5mL of constant volume in 100mL volumetric flask for color development) is theoretically higher by 0.65% -0.85% than the theoretical value, so as to overcome the method, the silicomolybdenum yellow photometry working curve adopts 1.6mgFe/100mL bottoming (containing reagent blank) for the standard, or 1.6mgFe/100mL solution is added with a color-developing agent as the interference of iron removal of the sample matrix blank button.

Based on this, in the invention, the selection, measurement and drawing of the standard working curve of the standard sample specifically include the following contents:

(21) selection of standard samples: taking silicon, nickel and iron elements as main objects, enabling the content of each element to be uniformly distributed in a measurement range as much as possible, and selecting 10-15 ferronickel samples (sampling according to the step (11)) as a standard sample series.

(22) Measurement of standard sample: for the selected 10-15 ferronickel samples, the contents of the chemical components thereof were measured by the chemical analysis method shown in table 3 above (chemical analysis was performed after "preparation of sample for chemical analysis" below was performed), and the spectral intensities of the chemical components thereof were measured by fluorescence analysis (fluorescence analysis was performed after "preparation of sample piece for fluorescence analysis" was performed at step (12)).

Preparation of samples for chemical analysis: the sample ingot is fixed on a bench drill, the rotating speed of a drill bit is set to 750r/min, after an oxide layer on a phi 35mm surface at the upper part of the sample ingot is removed, 50g of chip-shaped samples are drilled and put into a sample bag, and the sample bag is a sample for chemical analysis. The facilities used in the process are vertical bench drill, MODEL ZS4120, Zhejiang Xiling Limited company; cemented carbide drill, GD05-1000(Φ 10mm), zuo cemented carbide factory.

Each element to be measured in each standard sample was measured five times, and when the difference in the results was not more than the specified deviation, the average value was used as the standard result. Editing standard sample measuring software, inputting the chemical component content determined by each standard sample, measuring the determined standard sample according to the measuring conditions, and automatically storing the measuring intensity of each element to be measured by the instrument.

For example, 12 ferronickel samples were selected, numbered 1-12, and the contents W (%) and spectral intensities I (Kcps) of Ni, Fe, Si, Co, Cr, S, and P are shown in Table 4.

TABLE 4 content W (%) and spectral strength I (Kcps) of 12 samples of ferronickel

(23) Drawing a standard working curve: utilizing the measured intensity and the component content of each element analysis spectral line in the standard sample measured in the step (22), taking the percentage content of the elements as the abscissa and the intensity of the element spectral line as the ordinate, and applying a quadratic regression mathematical model W given by an instrument (ARL PERFORM X4200W-X-ray fluorescence analyzer, USA thermoelectric Co., Ltd.)_i＝a₀+a₁I+a₃I²And the function is to perform curve regression, automatically draw a working curve and store the working curve into a computer. In the formula: w_i-regression baseline (%); I-X-ray intensity (Kcps); a is₀、a₁、a₃-a curve constant.

Matrix correction, wherein a fluorescence analyzer provides various mathematical correction models for selective use, and under the sample collection method formulated by the invention, the calibration curve of each element in the ferronickel produced by the pyro-reduction smelting of the laterite-nickel ore has good linearity of a secondary (primary) regression curve, and a satisfactory measurement result can be obtained without matrix correction; when the laterite nickel ore raw ore is measured, an Additive Intensity Model (Additive Intensity Model) is adoptedWhen nickel in laterite is corrected, good calibration effect can be obtained.

Thirdly, the comparison result with the chemical analysis-the consistency test evaluation of the result with the chemical analysis

To check the reliability of the measurement results of the fluorescence analysis method (XRF) of the present invention, the results were compared with the chemical analysis method specified in the national standard (GB/T25049-2009), and the comparison data are shown in table 5 below.

TABLE 5 comparison of results of fluorescence and chemical analyses in ferronickel

The data in table 4 above visually shows that the fluorescence analysis result and the chemical analysis result agree with each other, and in order to more objectively evaluate the agreement between the fluorescence analysis result and the chemical analysis result, the following data agreement test was performed.

The detection method comprises the following steps: t test for consistency of paired data, test statistic is

Wherein:

n mean value of the difference of the measured values in pairs, d₀-is zero or a given value; n-logarithm of measurement; s_d-n standard deviations of the difference between the measured values; d_i-difference of fluorescence analysis measurement and chemical analysis measurement; and the degree of freedom is f-n-1, and a significance test of the difference value of the measurement result and zero (given value) is carried out by using a t distribution table.

5.1 consistency test of XRF measurement results and chemical analysis results of Nickel

The difference between the fluorescence analysis result and the chemical analysis result is: -0.07, -0.03, -0.01, 0.14, 0.20, 0.02, -0.08, -0.07, 0.11, -0.15, -0.19, -0.14, 0.11, -0.07.

Looking up t distribution table to obtain t_0.05,13＝2.160，t＝-0.5967≤t_0.05,132.160, indicating that the results of the nickel fluorescence analysis are consistent with those of the chemical analysis.

5.2 XRF measurement of iron consistency test with chemical analysis

The difference between the fluorescence analysis result and the chemical analysis result is: 0.13, -0.67, 1.26, -0.45, -0.62, -0.57, -0.74, 0.62, -0.75, 0.44, -0.59, 0.57;

looking up t distribution table to obtain t_0.05,13＝2.160，t＝-1.212≤t_0.05,132.160, which shows that the results of the iron fluorescence analysis are consistent with those of the chemical analysis.

5.3 consistency test of XRF measurement results and chemical analysis results of silicon

The difference between the fluorescence analysis result and the chemical analysis result is: 0.16, 0.10, 0.17, -0.26, 0.15, -0.21, 0.23, -0.19, -0.15, -0.10, -0.24, -0.31;

looking up t distribution table to obtain t_0.05,13＝2.160，t＝-0.763≤t_0.05,132.160, the fluorescence analysis result of silicon is consistent with the chemical analysis result.

5.4 consistency test of XRF measurement of chromium with chemical analysis

The difference between the fluorescence analysis result and the chemical analysis result is: -0.08, 0.06, 0.01, 0.14, 0.03, 0.04, -0.01, 0.17, -0.16, -0.15, -0.02, 0.15, 0.02;

looking up t distribution table to obtain t_0.05,13＝2.160，t＝0.939≤t_0.05,132.160, indicating that the fluorescence analysis of chromium is consistent with the chemical analysis.

5.5 XRF measurement of cobalt test for consistency with chemical analysis

The difference between the fluorescence analysis result and the chemical analysis result is: 0.04, 0, 0.04, 0.01, 0, 0.01, 0.04, -0.01, -0.02, 0.02;

looking up t distribution table to obtain t_0.05,13＝2.160，t＝0.535≤t_0.05,132.160, indicating that the fluorescence analysis result of cobalt is consistent with the chemical analysis result.

5.6 consistency test of XRF measurement of Sulfur with chemical analysis

The difference between the fluorescence analysis result and the chemical analysis result is: -0.02, 0, 0.02, 0.01, -0.01, 0.02, -0.02, 0.01, -0.01;

looking up t distribution table to obtain t_0.05,13＝2.160，t＝0.193≤t_0.05,132.160, indicating that the results of the fluorescence analysis of sulfur and the results of the chemical analysis are consistent.

5.7 consistency test of XRF measurement of phosphorus with chemical analysis

The difference between the fluorescence analysis result and the chemical analysis result is: 0.007, -0.002, 0.001, -0.001, 0, 0.00, -0.002, -0.001, -0.002, -0.001, 0, -0.001;

looking up t distribution table to obtain t_0.05,13＝2.160，t＝0.357≤t_0.05,132.160, indicating that the fluorescence analysis of phosphorus is consistent with the chemical analysis.

In conclusion, the measurement result of the invention is consistent with the current chemical analysis result, and the statistical test data shows that the result of the method is not significantly different from the current chemical analysis result, and the measurement result is consistent.

Compared with the prior art, the invention has the beneficial effects that:

(1) the method has the advantages that the melt is adopted directly, the obtained sample has excellent representativeness and high sampling speed, the report of a sample result can be completed within 40min, the labor efficiency is high, and the operation is simple and convenient;

(2) the direct sampling and rapid cooling of the melt are adopted, so that the calculation problem that the element standard working curve is not linear due to component segregation and the formation of a sample crystalline phase organization structure possibly caused by slow cooling of the sample is avoided.

(3) Realizes multi-element continuous measurement and has remarkable advantage of low cost

(4) The method realizes the rapid measurement of the sample in front of the furnace, and plays an active role in the high-efficiency stable control of the pyrometallurgical furnace.

The technical solution provided by the present invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.