CN115389283A

CN115389283A - Internal control sample in rare earth metal or alloy detection, preparation method and application

Info

Publication number: CN115389283A
Application number: CN202210729604.4A
Authority: CN
Inventors: 姚南红; 龚斌; 章立志; 温斌; 郭雪锋; 陈燕; 江媛
Original assignee: Ganzhou Ai Cree Detection Technology Co ltd
Current assignee: Ganzhou Ai Cree Detection Technology Co ltd
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2022-11-25

Abstract

The invention provides an internal control sample in rare earth metal or alloy detection, wherein the internal control sample is a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80mm and the height of 10-50mm. The internal control sample is applied to a spark direct-reading spectrometer for detecting rare earth metals or alloys, the relative standard deviation RSD of a parallel determination result is less than 5 percent, and the requirement of the internal control sample established as a standard curve point is met. The invention mixes a plurality of non-rare earth impurity elements into rare earth metals and alloys to prepare the internal control sample, and replaces the standard sample with the internal control sample meeting the quality control requirement, thereby solving the problem of establishing the standard curve point of the spark direct-reading spectrometer and realizing the online rapid detection of the spark direct-reading spectrometer on the production of the rare earth metals and alloys.

Description

Internal control sample in rare earth metal or alloy detection, preparation method and application

Technical Field

The invention belongs to the field of detection, and relates to an internal control sample, in particular to an internal control sample used in rare earth metal or alloy detection, and a preparation method and application thereof.

Background

Rare earth metals and alloys are important components of modern high-tech new materials, and are widely used in modern communication technology, electronic computers, aerospace development, medicine and health, photosensitive materials, photoelectric materials, energy materials, catalyst materials and the like.

The content of impurities in rare earth products is generally limited, the higher the content of impurity elements is, the poorer the product quality is, which is especially important for detecting non-rare earth elements influencing the performance and value of rare earth metals and alloys, and at present, different non-rare earth elements need to be detected by different methods and devices, for example: the elements Fe, al and Mo are detected by ICP, the element Si is detected by spectrophotometry and ICP, the element C is detected by a carbon-sulfur instrument, a surface oxide film of a sample needs to be removed and processed into chips or small blocks before detection, different elements need to be detected by a plurality of instruments, the pretreatment steps are long and tedious, the time from sampling to detection result is long, and the relation between on-line production process adjustment and product quality level cannot be quickly reflected, so that the quick and accurate analysis technology has important significance for on-line production process adjustment and product quality guarantee of rare earth metals and alloys, the production efficiency can be greatly improved, and the production cost can be saved. The application of the spark direct-reading spectrometer can solve the problems, firstly, a standard sample (an internal control sample) is a key link for quality control, has an important effect on controlling the quality of rare earth metal and alloy, is essential for establishing and correcting a working curve of an instrument, and is difficult to obtain the rare earth metal standard sample due to the particularity of easy oxidation and difficult preservation of the rare earth metal, so that no patent and literature disclosures on the preparation of the rare earth metal standard sample are disclosed at present. The patent develops a set of internal control samples meeting the quality control requirements, establishes a standard curve on a direct-reading spectrum, and is used for correcting working curve points.

At present, the content of non-rare earth in rare earth metals and alloys is usually 0.0010% -1.00%, and specific elements which generally affect the characteristics of the rare earth metals and alloys, such as Fe, al, mo, si, C and the like, are added with different dosages of different elements, and metal sample blocks with different gradient components are prepared by a melting method and are used for establishing and correcting standard curve points.

The conventional detection method takes a long time from sampling to detection result.

Disclosure of Invention

The invention solves the technical problems, realizes the application of the direct-reading spectrometer to the on-line rapid detection of the rare earth metal and the alloy, and can ensure the adjustment requirement of the product process in the production process and the product quality, thereby improving the production efficiency.

The invention provides an internal control sample in rare earth metal or alloy detection, wherein the internal control sample is a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80mm and the height of 10-50mm.

Preferably, the internal control sample is a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-50mm and the height of 10-20mm.

Further, the rare earth metal comprises yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium; the rare earth alloy metal comprises praseodymium-neodymium alloy, lanthanum-cerium alloy, praseodymium-neodymium-dysprosium alloy, praseodymium-neodymium-gadolinium alloy, praseodymium-neodymium-terbium-dysprosium alloy, dysprosium-iron alloy, holmium-iron alloy, gadolinium-iron alloy, neodymium-iron alloy, terbium-iron alloy, yttrium-iron alloy, erbium-iron alloy, rare earth-magnesium alloy and rare earth-aluminum alloy.

Furthermore, in the internal control sample, the main content of rare earth metal or rare earth alloy is 99.0-99.99%, and the content of non-rare earth is 0.010-1%;

the internal control sample is applied to a spark direct-reading spectrometer for detecting rare earth metals or alloys, the relative standard deviation RSD of the parallel determination result is less than 5 percent, and the requirement of the internal control sample established as a standard curve point is met.

The invention also provides a preparation method of the internal control sample in the detection of the rare earth metal or the alloy, which comprises the following steps:

the first step is as follows: raw material preparation

Rare earth metals and oxides thereof or rare earth alloy metals and oxides thereof: rare earth metal and its oxide with purity more than 99.9%, rare earth metal content 99.9%, powder or block;

non-rare earth elements: the purity of non-rare earth elements is more than 99.99 percent, and the elements are powder or blocks;

the second step is that: preparing internal control samples of rare earth metals and rare earth alloys:

controlling the content of non-rare earth by performing mixed melting or electrolytic melting on rare earth metal and oxide thereof or rare earth alloy metal and oxide thereof and non-rare earth elements to prepare an internal control sample;

thirdly, internal control sample surface treatment:

dry grinding with abrasive or machining to the required finish and flatness.

Preferably, in the second step, the smelting or electrolytic smelting step includes:

a. adding rare earth oxide into fluoride of the same rare earth element and lithium fluoride fused salt, and controlling the contents of Fe, al, mo and Si in the fused salt by taking a tungsten rod or a molybdenum rod as a cathode;

b. mixing and smelting rare earth metal or alloy and proper amount of non-rare earth elements, and controlling the contents of Fe, al, mo and Si in the metal.

c. During the electrolytic smelting of the rare earth oxide, the content of C in the metal is controlled by controlling the temperature and the anode effect time.

d. Mixing lanthanum (scraps) and rare earth oxide, adding the mixture into a carbon tube furnace, carrying out vacuum reduction distillation to obtain rare earth metal, and controlling the contents of Fe, al, mo and Si in the metal.

e. Mixing metal calcium and rare earth fluoride, putting the mixture into a tungsten crucible after mixing, carrying out vacuum reduction in an intermediate frequency furnace to obtain rare earth metal, and controlling the contents of Fe, al, mo and Si in the metal.

f. Putting the rare earth oxide into an electrolytic furnace which takes the same rare earth fluoride and lithium fluoride as molten salt, taking a pure iron rod as a cathode, electrolyzing the rare earth oxide to prepare rare earth alloy, and controlling the contents of Fe, al, mo and Si in the metal.

Pouring the mixture into a mold, cooling and taking out to obtain the rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80mm and the height of 10-50mm.

Preferably, in the third step,

the abrasive dry grinding comprises the following steps: dry grinding with a rotary disc type sample grinding machine or a belt sander, a grinding machine, wherein the grinding material types comprise corundum, silicon carbide, boron carbide, diamond and the like, and the grinding material particle size is less than or equal to 0.5mm;

the mechanical processing method comprises the following steps: and (3) carrying out surface treatment by adopting a lathe, a milling machine or a grinding machine, and controlling the processing speed to achieve the required surface smoothness and prevent the internal control sample from being oxidized due to overheating.

The preparation method of the internal control sample in the detection of the rare earth metal and the alloy also comprises the following steps:

and fourthly, detecting a fixed value:

and sampling and detecting the prepared internal control sample, and verifying and testing the uniformity and stability of the internal control sample.

The fifth step: and cutting and forming the fixed-value internal control sample to be used as the internal control sample for establishing the standard curve point.

And sixthly, vacuum storage.

In the fourth step, the detection result should not exceed the repeatability limit and reproducibility limit specified in the national standard; and drilling a proper amount of metal scraps at the upper, lower and middle positions of the prepared and surface-treated internal control sample, fully mixing, weighing five parts in parallel for chemical analysis, wherein the relative standard deviation RSD of a detection result is less than 5%, and the requirement of the internal control sample established as a standard curve point is met.

And in the fifth step, the sample is cut into a cylindrical internal control sample, wherein the diameter of the internal control sample is 40-80mm, and the height of the internal control sample is 10-50mm. The diameter of the internal control sample is preferably 40-50mm, and the height is preferably 10-20mm.

In the preparation method of the internal control sample in the detection of the rare earth metal and the alloy, the dosage of the rare earth metal or the rare earth alloy and the non-rare earth element is determined according to the total quantity of the internal control sample to be prepared, the proportion is between 100 and 1 and 1000, the main content of the prepared rare earth metal or the rare earth alloy is 99.0 to 99.99 percent, and the non-rare earth content is 0.010 to 1 percent.

Preferably, the preparation method of the internal control sample in the detection of the rare earth metal and the alloy comprises the following steps:

the first step, rare earth metal and its oxide with rare earth content more than 99.9% calculated by RE/REO and rare earth purity more than 99.9% calculated by RE/REO, including yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, praseodymium neodymium dysprosium, praseodymium neodymium gadolinium, doped non-rare earth element purity more than 99.99%, powder or block; rare earth alloys with rare earth purity of more than 99.9 percent calculated by RE, including praseodymium-neodymium alloy, lanthanum-cerium alloy, praseodymium-neodymium-dysprosium alloy, praseodymium-neodymium-gadolinium alloy, praseodymium-neodymium-terbium-dysprosium, dysprosium-iron alloy, holmium-iron alloy, gadolinium-iron alloy, neodymium-iron alloy, terbium-iron alloy, yttrium-iron alloy, erbium-iron alloy, rare earth magnesium alloy, rare earth aluminum alloy and the like, wherein the purity of doped non-rare earth elements is more than 99.99 percent, and the doped non-rare earth elements are in powder or block shapes;

secondly, performing mixed melting or electrolytic melting on rare earth metal and compounds thereof or rare earth alloy and compounds thereof and non-rare earth elements to control the non-rare earth content, and preparing an internal control sample, wherein the method comprises the following steps: a. adding rare earth oxide into fluoride of the same rare earth element and lithium fluoride fused salt, and controlling the contents of Fe, al, mo and Si in the fused salt by taking a tungsten rod or a molybdenum rod or a pure iron rod as a cathode; b. mixing and smelting rare earth metal or alloy and a proper amount of non-rare earth elements, and controlling the contents of Fe, al, mo and Si in the metal; c. during the electrolytic smelting of the rare earth oxide, the content of C in the metal is controlled by controlling the temperature and the anode effect time; d. mixing metal lanthanum scraps and rare earth oxide, adding the mixture into a carbon tube furnace, carrying out vacuum reduction distillation to obtain rare earth metal, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in an intermediate frequency furnace, and controlling the contents of Fe, al, mo and Si in the metal; e. mixing calcium metal and rare earth fluoride, mixing, loading into a tungsten crucible, performing vacuum reduction in an intermediate frequency furnace to obtain rare earth metal, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in the intermediate frequency furnace, and controlling the contents of Fe, al, mo and Si in the metal; f. putting rare earth oxide into an electrolytic furnace using the same kind of rare earth fluoride and lithium fluoride as molten salt, using a pure iron rod as a cathode, electrolyzing the rare earth oxide to prepare rare earth alloy, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in an intermediate frequency furnace, controlling the contents of Fe, al, mo and Si in the metal, pouring the mixture into a mold after the mixture is finished, cooling the mold, taking the mold out, and cutting the mold into a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80mm and the height of 10-50mm.

Preferably, the preparation method of the internal control sample of the rare earth metal and the alloy comprises the following steps:

a. putting rare earth oxide into an electrolytic furnace taking rare earth fluoride, lithium fluoride and the like as molten salt according to the weight ratio, melting at the temperature of 1000-1800 ℃ under the condition that the current is 4500-6500A, keeping the heating power of rare earth metal and alloy and non-rare earth metal elements in an intermediate frequency furnace at 80-150 KW, preserving the heat for 20-60 min to ensure that the materials are completely melted, and then refining the melt for 10-40 min at the temperature of 1100-1600 ℃;

b. casting the refined liquid metal rare earth into a vertical tungsten tube, wherein the casting temperature is 1100-1600 ℃, and cooling to obtain a rare earth metal cast ingot;

thirdly, surface treatment of an internal control sample: and (3) processing the smelted internal control sample to required smoothness and flatness by using an abrasive dry grinding or mechanical processing method.

The abrasive dry grinding comprises the following steps: dry grinding with a rotary disc sample grinder or a belt sander, a grinder, the grinding material types include corundum, silicon carbide, boron carbide, diamond and the like, and the grinding material particle is less than or equal to 0.5mm;

a mechanical processing method: performing surface treatment by adopting a lathe, a milling machine or a grinding machine, controlling the processing speed to achieve the required surface smoothness and preventing the internal control sample from being oxidized due to overheating;

the fourth step: and (3) constant value detection: sampling and detecting the prepared internal control sample, and verifying and testing the uniformity and stability of the internal control sample;

the fifth step: and cutting the constant value internal control sample into a cylinder to be used as the internal control sample for establishing the standard curve point.

The invention also provides the application of the internal control sample in the detection of rare earth metals and alloys.

The application is to use a direct-reading spectrometer to detect non-rare earth impurity elements in rare earth metals and alloys.

The rare earth metal comprises metal yttrium, metal lanthanum, metal cerium, metal praseodymium, metal neodymium, metal samarium, metal europium, metal gadolinium, metal terbium, metal dysprosium, metal holmium, metal bait, metal thulium, metal ytterbium and metal lutetium;

the rare earth alloy comprises a praseodymium-neodymium alloy, a lanthanum-cerium alloy, a praseodymium-neodymium-dysprosium alloy, a praseodymium-neodymium-gadolinium alloy, a praseodymium-neodymium-terbium-dysprosium alloy, a dysprosium-iron alloy, a holmium-iron alloy, a gadolinium-iron alloy, a neodymium-iron alloy, a terbium-iron alloy, a yttrium-iron alloy, an erbium-iron alloy, a rare earth-magnesium alloy and a rare earth-aluminum alloy.

The direct-reading spectrometer adopts atomic emission spectrometry, elements in a sample are directly gasified from a solid state and excited by high temperature of electric sparks to emit characteristic spectral lines of the elements, the intensity of the emission spectral line of each element is in direct proportion to the content of the element in the sample, the emission spectral line is split by a grating to form spectra arranged according to wavelength, the characteristic spectral lines of the elements are emitted into respective photomultiplier tubes through an emergent slit, optical signals are converted into electric signals, the electric signals are integrated, analog-to-digital converted by a control and measurement system of the instrument, and then the electric signals are processed by a computer, and the percentage content of each element is printed. Firstly, double clicking MetalLab32.exe, entering a database, selecting an internal control sample, newly establishing an internal control sample name, inputting an element name and content, and determining. And returning to the F4 calibration interface, clicking the excitation of the internal control sample, saving the data, and naming the newly-built program. Returning to the F2 analysis interface, selecting the wavelength of the element to be added in the channel in the newly-built program, selecting an analysis line, establishing a working curve, saving, naming the analysis program of the established matrix and saving as an STD calibration program. And returning to the F8 analysis interface, clicking the STD calibration program, exciting the internal control sample, and executing global standardization. And finally returning to the F7 program interface, clicking the established analysis program of the matrix, and after type calibration, starting sample detection and analysis.

In the detection of rare earth metals and alloys, a direct-reading spectrometer needs to establish standard curve points by using a standard sample.

Preferably, a standard curve is established on the spark direct-reading spectrometer; respectively exciting internal control samples with known content to obtain the spectral intensity of each element, making a standard curve according to the intensity ratio of each element to the matrix element and the content of the corresponding element, generally fitting by adopting a quadratic curve or a cubic curve, and performing element interference correction on the curve if necessary to ensure the accuracy of a detection result; the standard curve is a lasting curve, the curve does not need to be drawn again before a sample is analyzed each time, only the designated internal control sample is needed to carry out intensity correction and/or content correction on the curve, a corrected working curve and correction coefficients of all elements are obtained, the correction coefficients are about 1.0, and accurate and reliable test results of the established working curve can be guaranteed under the current state condition of the instrument.

And (3) sample analysis: and after the curve correction is finished, exciting the rare earth metal and alloy sample to be tested with the same matrix by using the same light source condition to obtain the content of the element to be tested.

The invention provides an internal control sample meeting quality control requirements in detection of rare earth metals and alloys to replace a standard sample, and a preparation method and application of the internal control sample. The internal control sample is used for detecting one sample in the detection of the rare earth metal and the alloy within 2 minutes on average, the detection results of various elements can be reported at one time, the product is not damaged and lost in the detection process, and the rare earth metal and the alloy can be recycled after the detection.

The preparation method of the internal control sample provided by the invention realizes the preparation of the internal control sample with the impurity element content distributed in a gradient manner by adopting an electrolysis method for special non-rare earth elements (such as C) through a specific method for doping and smelting non-rare earth elements in rare earth metals and alloys and controlling reaction conditions, solves the problem of establishing a standard curve point in the application of a direct-reading spectrometer to the online rapid detection of the rare earth metals and alloys, and meets the increasingly developed product control requirements of the rare earth metal and alloy industry and the requirements of online production product process adjustment and product quality assurance.

The beneficial effects of the invention are:

the invention mixes a plurality of non-rare earth impurity elements into rare earth metals and alloys to prepare the internal control sample, and replaces the standard sample with the internal control sample meeting the quality control requirement, thereby solving the problem of establishing the standard curve point of the spark direct-reading spectrometer and realizing the online rapid detection of the spark direct-reading spectrometer on the production of the rare earth metals and alloys.

The method has the advantages that the smelting mode is simple, the smelting process and steps are scientific and reasonable, the smelting enterprises in other industries can conveniently prepare standard samples meeting the requirements according to the requirements, all elements in the samples are parallelly tested for 5-6 times, the RSD values of the test results are all less than 5%, and the special requirement of establishing the standard curve points in the application of the spark direct-reading spectrometer in the rare earth industry is met.

Compared with the existing detection method, the direct-reading spectrum detection method for the rare earth metals and the alloys has the advantages that the detection speed is high, the efficiency is high, one sample is detected in 2 minutes on average, the detection results of various elements can be reported at one time, the detection surface is only required to be polished after the products are discharged from a furnace and cast, the products are not damaged and lost in the detection process, and the rare earth metals and the alloys after detection can be recycled. Different elements of the existing detection means need to be detected without instruments, the sample needs to be drilled into a chip shape or a block shape, the sample is easy to pollute, and the detection of one sample needs 1-2 days (if the molybdenum blue spectrophotometry is adopted to detect the total Si content in the rare earth metal, a. The sample is firstly made into the chip shape or the block shape and is uniformly mixed, 0.5h is needed, b. A standard solution and other reagent solutions needed for detection need 1 h. By adopting direct reading spectrum, 0.5kg of material can be saved per ton of metal, the unit price is 80 ten thousand yuan/ton calculated according to 5000 tons of annual production, 0.0005 is 5000 is 80=200 ten thousand yuan, and about 200 ten thousand yuan of rare earth is recycled every year.

The direct-reading spectrum is used for detecting the rare earth metal and the alloy, so that the online production guidance is facilitated, the stable quality of the product is ensured, and the establishment of an intelligent product production line can be realized; the cost can be reduced, for example, direct-reading spectrum is adopted to detect C and Fe with 0.5 yuan each, and the result can be reported at one time, while the current detection method adopts a carbon sulfur instrument to detect C with 6 yuan each and adopts an ICP method to detect Fe with 35 yuan each. The direct-reading spectrum is adopted, so that the cost can be greatly reduced every year.

Drawings

FIG. 1 shows samples of different specifications for internal control.

FIG. 2 is an internal control sample object.

FIG. 3 shows the detection step.

Detailed Description

1. Rare earth metals: a rare earth metal block having a rare earth content (in terms of RE) of greater than 99.9% and a rare earth purity (in terms of RE) of greater than 99.9%;

2. doping non-rare earth elements: the purity of non-rare earth elements is more than 99.99 percent, and the elements are powder or blocks. In the implementation of the invention, 4 elementary substances of Fe1535 ℃, al660 ℃, mo2617 ℃, si1410 ℃, and the like are prepared.

3. Preparing internal control samples of rare earth metals and rare earth alloys: rare earth metal and rare earth alloy are smelted with a certain amount of non-rare earth elements, and the content of C in a sample is controlled by controlling the time of anode reaction in the electrolysis process of special element C. Different metals are smelted by adopting separate containers.

The specific smelting process comprises the following steps: a. adding rare earth oxide into a molten salt system consisting of fluoride and lithium fluoride of the same rare earth element, and controlling the contents of Fe, al, mo and Si in the molten salt by taking a tungsten rod as a cathode; b. further mixing and smelting rare earth metal or alloy and proper amount of non-rare earth elements, and controlling the content of Fe, al, mo and Si in the metal; c. or the content of C in the metal is controlled by controlling the temperature and the anode effect time in the electrolytic smelting process. And pouring the mixture into a mold after smelting is finished, cooling the mixture, taking the mixture out, performing chemical analysis to determine a value, and cutting the mixture to prepare a corresponding sample block. The dosage of the rare earth metal or the rare earth alloy and the non-rare earth element is determined according to the total amount of the internal control sample required to be prepared, the main content of the prepared rare earth metal or the rare earth alloy is 99.0 to 99.99 percent, and the non-rare earth content is 0.0050 to 1 percent.

4. Note: in the embodiment of the invention, 6 internal control samples need to be prepared for each type of metal, the serial numbers are respectively No. 1, no. 2, no. 3, no. 4, no. 5 and No. 6, and the content of each element can be set from low to high according to a preparation range table of the internal control samples.

5. Internal control sample preparation table:

a. rare earth metals and rare earth alloys

b. Rare earth ferroalloys

c. Rare earth magnesium alloys

d. Rare earth aluminum alloys

Note: firstly, the content of related impurities in the rare earth metal and the rare earth alloy is measured, and the total amount of the related impurities in the final sample is controlled.

6. Surface treatment of an internal control sample: and (3) processing the smelted internal control sample to required smoothness and flatness by using an abrasive dry grinding or mechanical processing method.

7. And (3) internal control sample fixed value detection: a. detecting Fe and Al in rare earth metal according to GB/T12690.5-2017 method, dissolving the sample in nitric acid, directly exciting in dilute nitric acid medium by argon plasma light source, and determining; dissolving Fe in the dysprosium-iron alloy by using hydrochloric acid, reducing ferric iron into ferrous iron by using titanium trichloride to generate tungsten blue by using sodium tungstate as an indicator after a sample is dissolved by using the method of GB/T26416.4-2010, dropwise adding a potassium dichromate primary adjustment solution to oxidize excessive trivalent titanium, adding mixed sulfuric-phosphoric acid, using sodium diphenylamine sulfonate as the indicator, and titrating by using a potassium dichromate standard solution to purple as an end point; b. according to the method of GB/T12690.13-2003, mo is detected, a sample is dissolved by nitric acid and hydrofluoric acid, a rare earth matrix is separated, and argon plasma light source excitation is carried out to determine Mo; c. detecting Si according to a GB/T12690.7-2021 method, a spectrophotometry method: dissolving a sample by using hydrochloric acid or nitric acid, generating silicomolybdic heteropoly acid by using silicon and ammonium molybdate in a hydrochloric acid medium of 0.12-0.25 mol/L, decomposing phosphorus and arsenic heteropoly acid by using grass-sulfur mixed acid, reducing the silicomolybdic heteropoly acid into blue low-valence complex by using ascorbic acid, and measuring the absorbance of the blue low-valence complex at the wavelength of 800nm of a spectrophotometer; ICP-OES method: the sample is dissolved by dilute nitric acid, the emission intensity of silicon is measured in dilute acid medium at the wavelength selected by an inductively coupled plasma atomic emission spectrometer, and the content of silicon is calculated by a working curve. Correcting the influence of the matrix on the measurement by a matrix matching method; d. test C A sample was subjected to high-frequency combustion in an oxygen atmosphere in a high-frequency induction furnace in the presence of a cosolvent in accordance with GB/T12690.1-2015, and carbon was released as carbon dioxide, which was then measured by an infrared absorption method.

8. Preparing an internal control sample:

firstly, rare earth metals and oxides thereof with the rare earth content (calculated by RE/REO) of more than 99.9 percent and the rare earth purity (calculated by RE/REO) of more than 99.9 percent comprise yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, bait, thulium, ytterbium and lutetium, and doped non-rare earth elements with the purity of more than 99.99 percent are in powder or block shapes; rare earth alloys with rare earth purity (calculated as RE) of more than 99.9 percent, including praseodymium-neodymium alloy, lanthanum-cerium alloy, praseodymium-neodymium-dysprosium alloy, praseodymium-neodymium-gadolinium alloy, praseodymium-neodymium-terbium alloy, praseodymium-neodymium-dysprosium, dysprosium-iron alloy, holmium-iron alloy, gadolinium-iron alloy, neodymium-iron alloy, terbium-iron alloy, yttrium-iron alloy, erbium-iron alloy, rare earth-magnesium alloy, rare earth-aluminum alloy and the like, doped non-rare earth elements with purity of more than 99.99 percent, powder or block;

the purity of the rare earth is the relative purity of the rare earth. The rare earth purity refers to the mass fraction of the main component of rare earth metal or oxide in the mixture, and is expressed by percentage; the relative purity of rare earth refers to the mass fraction of a certain rare earth element (metal or oxide) in the total amount of rare earth (metal or oxide), and is expressed as percentage.

Secondly, performing mixed melting or electrolytic melting on rare earth metal and compounds thereof or rare earth alloy and compounds thereof and non-rare earth elements to control the non-rare earth content, and preparing an internal control sample, wherein the method comprises the following steps: a. adding rare earth oxide into fluoride of the same rare earth element and lithium fluoride fused salt, and controlling the contents of Fe, al, mo and Si in the fused salt by taking a tungsten rod or a molybdenum rod or a pure iron rod as a cathode; b. mixing metal lanthanum (scraps) and rare earth oxide, adding the mixture into a carbon tube furnace, carrying out vacuum reduction distillation to obtain rare earth metal, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in an intermediate frequency furnace, and controlling the contents of Fe, al, mo and Si in the metal; c. mixing and smelting rare earth metal or alloy and a proper amount of non-rare earth elements, and controlling the contents of Fe, al, mo and Si in the metal; d. during the electrolytic smelting of the rare earth oxide, the content of C in the metal is controlled by controlling the temperature and the anode effect time; e. mixing calcium metal and rare earth fluoride, mixing, loading into a tungsten crucible, performing vacuum reduction in an intermediate frequency furnace to obtain rare earth metal, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in the intermediate frequency furnace, and controlling the contents of Fe, al, mo and Si in the metal; f. putting rare earth oxide into an electrolytic furnace which takes the same rare earth fluoride and lithium fluoride as molten salt, taking a pure iron rod as a cathode, electrolyzing the rare earth oxide to prepare rare earth alloy, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in an intermediate frequency furnace, controlling the contents of Fe, al, mo and Si in the metal, pouring the mixture into a mold after the mixture is melted, cooling the mold, taking the mold out, and cutting the mold to obtain a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 50mm and the height of 20 mm;

further, the method comprises the following steps:

thirdly, surface treatment of an internal control sample: processing the smelted internal control sample to required smoothness and flatness by using an abrasive dry grinding or mechanical processing method;

a mechanical processing method: and (3) carrying out surface treatment by adopting a lathe, a milling machine or a grinding machine, and controlling the processing speed to achieve the required surface smoothness and prevent the internal control sample from being oxidized due to overheating.

The fourth step: and (3) constant value detection: and sampling and detecting the prepared internal control sample, testing, verifying and fixing the uniformity and stability of the internal control sample, wherein the detection result does not exceed the repeatability limit and the reproducibility limit specified in the national standard. Drilling a proper amount of metal scraps at the upper, lower and middle positions of the prepared and surface-treated internal control sample block, fully mixing, weighing 11 parts in parallel for chemical analysis, wherein the relative standard deviation RSD of a detection result is less than 5%, and the detection result meets the quality requirement of an internal control sample established as a standard curve point;

the fifth step: cutting the sample after the value setting into a cylinder (see figures 1 and 2) to be used as an internal control sample for establishing a standard curve point;

9. sample detection

A standard curve was established on a spark direct-reading spectrometer. The internal control samples with known content are respectively excited to obtain the spectral intensity of each element, the intensity ratio of each element to the matrix element is used for making a standard curve according to the corresponding element content, a quadratic curve or a cubic curve is generally adopted for fitting, element interference correction is carried out on the curve if necessary, and the accuracy of the detection result is ensured. The standard curve is a lasting curve, the curve does not need to be drawn again before a sample is analyzed each time, only a specified internal control sample is needed to carry out intensity correction and/or content correction on the curve, a corrected working curve and correction coefficients of all elements are obtained, and the correction coefficients are about 1.0, so that the established working curve can be ensured to obtain an accurate and reliable test result under the current state condition of the instrument;

and (3) sample analysis: and after the curve correction is finished, exciting the rare earth metal and alloy sample to be detected with the same matrix under the same light source condition to obtain the content of the element to be detected.

The test instrument: model of spark direct-reading spectrometer: GNR 300 manufacturer: G.N.R

Example one

Putting neodymium oxide into an electrolytic furnace which takes neodymium fluoride and lithium fluoride =10 (weight ratio) as fused salt, controlling the content of Fe and Mo in the fused salt by taking a tungsten rod as a cathode at the temperature of 1130 ℃ under the condition that the electrolytic current is 6000A, collecting electrolyzed metal neodymium in a molybdenum crucible, stirring the liquid metal neodymium after the liquid metal neodymium in the molybdenum crucible reaches a certain amount, taking out the molybdenum crucible, erecting a preheated tungsten tube which is oppositely stripped into two halves along the length direction, casting the liquid metal neodymium in the molybdenum crucible into the erected tungsten tube, cooling and cutting into multiple sections to prepare a cylindrical metal neodymium sample with the diameter of 50mm and the height of 20mm as shown in figure 1.

Detecting the Fe content in a metal neodymium sample according to a GB/T12690.5-2017 method ICP-AES, drilling cuttings on the sample to be detected and fully mixing, taking 0.5000g of the sample, taking three parts in parallel, adding 5mL of nitric acid-water (1);

detecting the Mo content in a metal neodymium sample according to a GB/T12690.13-2003 method ICP-AES, drilling cuttings on the sample to be detected, fully mixing, taking 1.0000g of the sample, taking three parts in parallel, adding a little water and 10mL of nitric acid into a 200mL polytetrafluoroethylene beaker, heating for dissolving, adding about 50mL of water, heating to near boiling, adding 2.0mL of hydrofluoric acid, heating to near boiling, keeping the temperature for 10min, standing and cooling to room temperature, transferring into a 100mL volumetric flask, diluting with water to a scale, shaking up, after precipitation and settlement, carrying out dry filtration by using two pieces of slow filter paper. 10mL of the filtrate was transferred to a 25mL volumetric flask, and 2.5mL of a boric acid solution (50 g/L) was added, diluted to the mark with water, and shaken up. Calibrating the ICP-AES by taking a standard solution, and determining a sample under the condition of good accuracy and stability of the ICP-AES to obtain the average value of three parts of Mo in metal neodymium of 0.050%;

a direct-reading spectrometer (model GNR 300, manufacturer: G.N.R; the same below) is adopted to measure the contents of Fe and Mo in a metallic neodymium sample, a metallic neodymium cylindrical sample with the diameter of 50mm and the height of 20mm is processed to the required smoothness and flatness, and the cylindrical sample is placed on a spark table for dotting scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; humidity is 50-60%; purging time 5s, pre-burning 5s and burning 15s. And (3) dotting and scanning the surface of the neodymium metal sample by using a direct-reading spectrometer to obtain that the contents of Fe and Mo are 1.088% and 0.051% respectively. The details are shown in the table I.

Example two

Putting praseodymium oxide into an electrolytic furnace using praseodymium fluoride, lithium fluoride =80 (weight ratio) as molten salt, electrolyzing 6530A at 1070 ℃, using a molybdenum rod as a cathode, controlling the content of Si in the molten salt, collecting metal praseodymium obtained by electrolysis in a tungsten crucible, stirring the liquid metal praseodymium after the liquid metal praseodymium in the tungsten crucible reaches a certain amount, taking out the tungsten crucible, erecting a preheated tungsten tube which is split into two halves along the length direction, casting the liquid metal praseodymium in the tungsten crucible in the erected tungsten tube, cooling and cutting into multiple sections to prepare a metal praseodymium cylindrical sample with the diameter of 50mm and the height of 20mm as shown in figure 1.

Measuring the Si content in a metal praseodymium sample according to the spectrophotometry method in the method GB/T12690.7-2021, cutting and mixing well on a sample to be measured, taking 2.0000g of a sample, taking three parts in parallel, placing in a 100mL polytetrafluoroethylene beaker, adding 10mL of nitric acid-water (1;

and (3) measuring the content of Si in the metal praseodymium sample by adopting a direct-reading spectrometer, processing the metal praseodymium cylindrical sample with the diameter of 50mm and the height of 20mm to the required smoothness and flatness, and placing the metal praseodymium cylindrical sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) performing dotting scanning on the surface of the metal praseodymium sample by using a direct-reading spectrometer to obtain the Si content of 0.21%. The details are shown in the table I.

EXAMPLE III

Putting praseodymium-neodymium oxide into an electrolytic furnace using praseodymium-neodymium fluoride, lithium fluoride =88 (weight ratio) as molten salt, controlling the content of Mo in the molten salt by using a tungsten rod as a cathode at the temperature of 1100 ℃, collecting a praseodymium-neodymium alloy obtained by electrolysis in a tungsten crucible, stirring the liquid praseodymium-neodymium alloy and taking out the tungsten crucible after the liquid praseodymium-neodymium alloy in the tungsten crucible reaches a certain quantity, erecting a preheated tungsten tube which is oppositely stripped into two halves along the length direction, casting the liquid praseodymium-neodymium alloy in the tungsten crucible in the erected tungsten tube, cooling and cutting into multiple sections to prepare into the shape shown in figure 1, thereby obtaining a praseodymium-neodymium alloy cylindrical sample with the diameter of 50mm and the height of 20mm.

Detecting Mo content in a praseodymium-neodymium alloy sample according to an ICP-AES method of GB/T12690.13-2003, drilling cuttings on the sample to be detected, fully mixing, taking 1.0000g of the sample, taking three parts in parallel, adding a little water and 10mL of nitric acid into a 200mL polytetrafluoroethylene beaker, heating for dissolving, adding about 50mL of water, heating to near boiling, adding 5.0mL of hydrofluoric acid, heating to near boiling, preserving heat for 10min, standing for cooling to room temperature, transferring into a 100mL volumetric flask, diluting with water to a scale, shaking uniformly, and after precipitation and settlement, carrying out dry filtration by using two pieces of slow-speed filter paper. 2mL of the filtrate was transferred to a 25mL volumetric flask, and 2.5mL of a boric acid solution (50 g/L) was added, diluted to the mark with water, and shaken up. Calibrating the ICP-AES by taking a standard solution, and determining a sample under the condition of good accuracy and stability of the ICP-AES to obtain the three-part average value of Mo in the praseodymium-neodymium alloy of 0.011 percent;

and (3) measuring the content of Mo in the metal praseodymium-neodymium sample by adopting a direct-reading spectrometer, processing the metal praseodymium-neodymium cylindrical sample with the diameter of 50mm and the height of 20mm to required fineness and flatness, and placing the sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; the humidity is 50-60%; purging time 5s, pre-burning 5s and burning 15s. And (3) performing dotting scanning on the surface of the praseodymium-neodymium metal sample by using a direct-reading spectrometer to obtain the Mo content of 0.013%. The details are shown in the table I.

Example four

Mixing metal lanthanum (scraps) and ytterbium oxide, pressing the mixture into a phi 50x80 cylinder after mixing, adding the cylinder into a carbon tube furnace, and carrying out vacuum reduction distillation to obtain the ytterbium metal. And distilling and purifying the crude ytterbium product to obtain refined ytterbium. Uniformly stirring metal ytterbium with a proper amount of pure aluminum and pure silicon, uniformly mixing, casting liquid metal ytterbium in a tungsten crucible into a vertical tungsten tube, cooling to obtain a metal ytterbium sample containing iron elements and aluminum elements, cutting into multiple sections, preparing into a shape as shown in figure 1, and obtaining a metal ytterbium cylindrical sample with the diameter of 50mm and the height of 20mm.

Detecting the Al content in a ytterbium metal sample according to a GB/T12690.5-2017 method ICP-AES, applying drill cuttings to the sample to be detected, fully mixing, taking 0.5000g of the sample, taking three parts in parallel, adding 5mL of nitric acid-water (1), heating at a low temperature to completely dissolve, cooling to room temperature, transferring into a 50mL volumetric flask, diluting to a scale with water, shaking up, transferring 10.00mL into a 100mL volumetric flask, diluting to a scale with water, shaking up, taking a standard solution to calibrate the ICP-AES, measuring the sample under the condition that the accuracy and stability of the ICP-AES are good, and obtaining the average value of the three parts of Al in the ytterbium metal, which is 0.0052%;

measuring the content of Si in a metal ytterbium sample according to a spectrophotometric method in a GB/T12690.7-2021 method, drilling cuttings on a sample to be measured and fully mixing, taking 2.0000g of a sample, taking three parts in parallel, placing the sample in a 100mL polytetrafluoroethylene beaker, adding 10mL of nitric acid-water (1;

and (3) measuring the contents of Al and Si in the ytterbium metal sample by using a direct-reading spectrometer, processing a ytterbium metal cylindrical sample with the diameter of 50mm and the height of 20mm to the required degree of finish and flatness, and placing the ytterbium metal cylindrical sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/light chamber temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. The surface of the ytterbium metal sample was spot scanned with a direct-reading spectrometer to obtain Al and Si contents of 0.0051% and 0.208%, respectively. The details are shown in the table I.

EXAMPLE five

Respectively melting and mixing metal gadolinium and a proper amount of pure iron, adding a proper amount of pure aluminum sheets while the mixture is hot, uniformly stirring, after the reaction is completed, casting liquid metal gadolinium in a tungsten crucible into a vertical tungsten tube, cooling to obtain a metal gadolinium sample containing iron elements and aluminum elements, cutting the metal gadolinium sample into multiple sections, and preparing the metal gadolinium sample into a shape as shown in figure 1 to obtain a metal gadolinium cylindrical sample with the diameter of 50mm and the height of 20mm.

Detecting the contents of Fe and Al in a metal gadolinium sample according to an ICP-AES method GB/T12690.5-2017, drilling cuttings on the sample to be detected and fully mixing, taking 0.5000g of the sample, taking three parts in parallel, adding 5mL of nitric acid-water (1);

and (3) measuring the contents of Fe and Al in the metal gadolinium sample by using a direct-reading spectrometer, processing the metal gadolinium cylindrical sample with the diameter of 50mm and the height of 20mm to required smoothness and flatness, and placing the sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) performing dotting scanning on the surface of the metal gadolinium sample by using a direct-reading spectrometer to obtain that the contents of Fe and Al are 0.522% and 0.518%, respectively. The details are shown in the table I.

EXAMPLE six

Putting neodymium oxide into an electrolytic furnace which takes neodymium fluoride and lithium fluoride =89 (weight ratio) as molten salt, electrolyzing the neodymium oxide to prepare a metal neodymium sample at the temperature of 1140 ℃ by taking a tungsten rod as a cathode, controlling the time of anode effect generation for 5 minutes before discharging, casting liquid metal neodymium in a tungsten crucible into a vertical tungsten tube, cooling and cutting into a plurality of sections to prepare the metal neodymium cylindrical sample with the diameter of 50mm and the height of 20mm as shown in figure 1.

Detecting the content of C in a metal neodymium sample by a high-frequency-infrared carbon-sulfur instrument according to a GB/T12690.1-2015 method, fully mixing drill cuttings on the sample to be detected, adding 1.2g of tungsten cosolvent, 0.1g of tin cosolvent and 0.3g of iron cosolvent into a crucible, adding 0.3000g of a sample, taking three parts in parallel, and determining on the high-frequency-infrared carbon-sulfur instrument, wherein the average value of the three parts is 0.051%;

measuring the content of C in the metallic neodymium sample by adopting a direct-reading spectrometer, processing the metallic neodymium cylindrical sample with the diameter of 50mm and the height of 20mm to the required fineness and flatness, and placing the cylindrical sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/light chamber temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) dotting and scanning the surface of the neodymium metal sample by using a direct-reading spectrometer to obtain the C content of 0.051%. The details are shown in the table I.

EXAMPLE seven

Putting praseodymium oxide into an electrolytic furnace using praseodymium fluoride/lithium fluoride =87 (weight ratio) as molten salt, electrolyzing the praseodymium oxide by using a tungsten rod as a cathode and 1050 and 6500A as electrolytic current in the electrolytic furnace to prepare a metal praseodymium sample, controlling the time for generating an anode effect for 6 minutes before discharging, casting liquid metal praseodymium in a molybdenum crucible into a vertical tungsten tube, cooling and cutting the liquid metal praseodymium into multiple sections to prepare a metal praseodymium cylindrical sample with the diameter of 50mm and the height of 20mm as shown in figure 1.

Detecting the content of C in a metal praseodymium sample by a high-frequency-infrared carbon sulfur instrument according to a GB/T12690.1-2015 method, adding drill cuttings on a sample to be detected, fully mixing, adding 1.2g of tungsten cosolvent, 0.1g of tin cosolvent and 0.3g of iron cosolvent into a crucible, adding 0.3000g of a sample, taking three parts in parallel, and determining on the high-frequency-infrared carbon sulfur instrument, wherein the average value of the three parts is 0.20%;

and (3) measuring the content of C in the metal praseodymium sample by adopting a direct-reading spectrometer, processing the metal praseodymium cylindrical sample with the diameter of 50mm and the height of 20mm to the required fineness and flatness, and placing the metal praseodymium cylindrical sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) performing dotting scanning on the surface of the metal praseodymium sample by using a direct-reading spectrometer to obtain a sample with the C content of 0.215%. The details are shown in the table I.

Example eight

The praseodymium neodymium oxide is put into an electrolytic furnace which takes praseodymium neodymium fluoride: lithium fluoride =90 (weight ratio) as fused salt, a tungsten rod is taken as a cathode, the praseodymium neodymium oxide is electrolyzed in the electrolytic furnace at 1110 ℃ and current 5500A to prepare a metal praseodymium neodymium sample, the time for generating anode effect is controlled for 8 minutes before discharging, the liquid metal praseodymium neodymium in a molybdenum crucible is cast in a vertical tungsten tube, and the liquid metal praseodymium neodymium is cut into a plurality of sections after cooling to prepare the shape as shown in figure 1, and the metal praseodymium neodymium column sample with the diameter of 50mm and the height of 20mm is obtained.

Detecting the content of C in a metal praseodymium-neodymium sample by a high-frequency-infrared carbon sulfur instrument according to a GB/T12690.1-2015 method, drilling cuttings on the sample to be detected and fully mixing, adding 1.2g of tungsten cosolvent, 0.1g of tin cosolvent and 0.3g of iron cosolvent into a crucible, adding 0.3000g of a sample, taking three parts in parallel, and determining on the high-frequency-infrared carbon sulfur instrument, wherein the average value of the three parts is 0.51%;

and (3) measuring the content of C in the metal praseodymium-neodymium sample by adopting a direct-reading spectrometer, processing the metal praseodymium-neodymium cylindrical sample with the diameter of 50mm and the height of 20mm to the required degree of finish and flatness, and placing the sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) performing dotting scanning on the surface of the metal praseodymium-neodymium sample by using a direct-reading spectrometer to obtain the content of C of 0.518%. The details are shown in the table I.

Example nine

Mixing the metal calcium and the dysprosium fluoride, filling the mixture into a tungsten crucible, and carrying out vacuum reduction in an intermediate frequency furnace to obtain the metal dysprosium. And filling the product metal dysprosium and a proper amount of pure aluminum into a tungsten crucible, vacuumizing and uniformly stirring, after the reaction is completed, casting the liquid metal dysprosium in the tungsten crucible into a vertical tungsten tube, cooling to obtain a metal dysprosium sample of an aluminum element, and cutting into a multi-section product. Prepared into the shape shown in figure 1 to obtain a metallic dysprosium cylinder sample with the diameter of 50mm and the height of 20mm.

Detecting the Al content in a metal dysprosium sample according to an ICP-AES method GB/T12690.5-2017, drilling cuttings on the sample to be detected and fully mixing, taking 0.5000g of the sample, taking three parts in parallel, adding 5mL of nitric acid-water (1);

and (3) measuring the content of Al in the metal dysprosium sample by using a direct-reading spectrometer, processing the metal dysprosium cylindrical sample with the diameter of 50mm and the height of 20mm to the required degree of finish and flatness, and placing the metal dysprosium cylindrical sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/the light room temperature is 20 ℃; the humidity is 50-60%; purging time 5s, pre-burning 5s and burning 15s. And (3) performing dotting scanning on the surface of the metal dysprosium sample by using a direct-reading spectrometer to obtain that the content of Al is 0.012%. The details are shown in the table I.

Example ten

Dysprosium oxide is put into an electrolytic furnace which takes dysprosium fluoride: lithium fluoride =92 (weight ratio) as molten salt, dysprosium oxide is electrolyzed in the electrolytic furnace at 1170 ℃ by taking a pure iron rod as a cathode to prepare a dysprosium-iron alloy sample, the time of generating anode effect is controlled for 5 minutes before discharging, the liquid dysprosium-iron alloy in a crucible is cast in a vertical tungsten tube, and the dysprosium-iron alloy is cooled and cut into multiple sections to prepare a dysprosium-iron alloy cylindrical sample with the diameter of 50mm and the height of 20mm as shown in figure 1.

Measuring the Fe content of a Dy-Fe alloy sample according to a GB/T26416.4-2010 method potassium dichromate volumetric method, drilling cuttings on a sample to be measured, fully mixing, weighing 5.0000g, taking three parts in parallel, placing in a 300mL beaker, adding 30mL hydrochloric acid, covering a watch glass, heating at a low temperature until the sample is completely dissolved, cooling to room temperature, transferring into a 250mL volumetric flask, diluting to a scale, and shaking uniformly. Transferring 10mL into a 300mL triangular flask, flushing the inner wall with a small amount of water, adding 1mL of sodium tungstate solution (250 g/L), dropwise adding titanium trichloride solution (150-200 g/mL of titanium trichloride is diluted 20 times with hydrochloric acid-water (1). 10mL of mixed sulfuric-phosphoric acid (300 mL of sulfuric acid is slowly injected into 500mL of water under continuous stirring, then 300mL of phosphoric acid is added, the mixture is diluted to 1000mL of water and shaken up), 2 drops of sodium diphenylamine sulfonate indicator (5 g/L) are added, and the mixture is immediately titrated with a potassium dichromate standard solution (0.01038 mol/L) until purple color does not disappear within 30 s. The average result of three parts is calculated to be 20.13%;

detecting the content of C in a dysprosium-iron alloy sample by a high-frequency-infrared carbon sulfur instrument according to a GB/T12690.1-2015 method, adding drill cuttings on the sample to be detected, fully mixing, adding 1.2g of tungsten cosolvent, 0.1g of tin cosolvent and 0.3g of iron cosolvent into a crucible, adding 0.3000g of a sample, taking three parts in parallel, and determining on the high-frequency-infrared carbon sulfur instrument, wherein the average value of the three parts is 0.012%;

and (3) determining the content of Fe and C in the Dy-Fe alloy sample by using a direct-reading spectrometer, processing the Dy-Fe alloy cylindrical sample with the diameter of 50mm and the height of 20mm to the required smoothness and flatness, and placing the Dy-Fe alloy cylindrical sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/light chamber temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And performing dotting scanning on the surface of the Dy-Fe alloy sample by using a direct-reading spectrometer to obtain that the contents of Fe and C are 20.22 and 0.013 respectively. The details are shown in the table I.

EXAMPLE eleven

Melting metal gadolinium (30 wt%) and metal magnesium (69 wt%), mixing, adding a proper amount of pure iron sheet while the mixture is hot, stirring uniformly, after the reaction is completed, casting the liquid metal gadolinium-magnesium in a tungsten crucible into a vertical tungsten tube, cooling to obtain a metal gadolinium-magnesium sample containing iron element, cutting the sample into multiple sections, and preparing the sample into a shape as shown in figure 1 to obtain a metal gadolinium-magnesium cylindrical sample with the diameter of 50mm and the height of 20mm.

Detecting the Fe content in a metal gadolinium magnesium sample according to a GB/T12690.5-2017 method ICP-AES, drilling cuttings on the sample to be detected and fully mixing, taking 0.5000g of the sample, taking three parts in parallel, adding 5mL of nitric acid-water (1);

and (3) measuring the content of Fe in the metal gadolinium-magnesium sample by using a direct-reading spectrometer, processing the metal gadolinium-magnesium cylindrical sample with the diameter of 50mm and the height of 20mm to the required smoothness and flatness, and placing the sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/light chamber temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) performing dotting scanning on the surface of the metal gadolinium-magnesium sample by using a direct-reading spectrometer to obtain that the content of Fe is 0.22%. The details are shown in the table I.

Example twelve

Melting and mixing metal yttrium (30 wt%) and metal aluminum (69 wt%), adding a proper amount of pure silicon while the mixture is hot, uniformly stirring, after the reaction is completed, casting the liquid metal yttrium aluminum in the tungsten crucible into a vertical tungsten tube, cooling to obtain a metal yttrium aluminum sample containing silicon element, cutting the sample into multiple sections, and preparing the sample into a shape shown in figure 1 to obtain a metal yttrium aluminum cylindrical sample with the diameter of 50mm and the height of 20mm.

Measuring the content of Si in a metal yttrium aluminum sample according to a spectrophotometric method in a GB/T12690.7-2021 method, drilling cuttings on a sample to be measured and fully mixing, taking 2.0000g of a sample, taking three parts in parallel, placing the three parts in a 100mL polytetrafluoroethylene beaker, adding 10mL of nitric acid-water (1;

and (3) measuring the content of Si in the metal yttrium aluminum sample by using a direct-reading spectrometer, processing the metal yttrium aluminum cylindrical sample with the diameter of 50mm and the height of 20mm to the required smoothness and flatness, and placing the sample on a spark table for dotting and scanning. Setting the working conditions of the direct-reading spectrometer: the voltage is 220V, 50-60 Hz, the voltage-stabilized power supply is 3KVA, the independent ground wire is less than 4 omega, the purity is more than 99.999 percent, the argon input pressure is 4bar (0.4 MPa), and the flow rate is controlled to be 8L/min; the ambient temperature is 25 ℃/light chamber temperature is 20 ℃; the humidity is 50-60%; purge time 5s, precombustion 5s, and combustion 15s. And (3) dotting and scanning the surface of the metal yttrium aluminum sample by using a direct-reading spectrometer to obtain the Si content of 0.53%. The details are shown in the table I.

EXAMPLE thirteen

Putting praseodymium-neodymium oxide into an electrolytic furnace using praseodymium-neodymium fluoride, lithium fluoride =88 (weight ratio) as molten salt, controlling the content of Fe, si, al and Mo in the molten salt by using a tungsten rod as a cathode at the temperature of 1100 ℃, collecting praseodymium-neodymium metal liquid obtained by electrolysis in a tungsten crucible, fully stirring the liquid praseodymium-neodymium metal in the tungsten crucible after the liquid praseodymium-neodymium metal reaches a certain amount, controlling the time of anode effect generation for 8 minutes before discharging to control the content of C in the praseodymium-neodymium metal, taking out the tungsten crucible, casting the liquid praseodymium-neodymium metal in the tungsten crucible into a vertical tungsten tube, cooling and cutting into multiple sections to obtain a praseodymium-neodymium metal cylindrical sample with the diameter of 50mm and the height of 20mm.

Detecting Fe, al and Mo elements by using an ICP-AES (inductively coupled plasma-atomic emission spectrometry) method by using a conventional chemical analysis method, detecting Si elements by using a spectrophotometry method, detecting C elements by using a high-frequency-infrared carbon-sulfur instrument, drilling a proper amount of scraps or blocks at the upper, lower and middle positions of a praseodymium-neodymium alloy sample block, fully mixing, detecting 5 elements by using 10-15 g of samples, and reporting 1-2 days from the detection result of the 5 elements after sampling (if the Si content in rare earth metal is detected by using a molybdenum blue spectrophotometry method, a, the samples are firstly made into scraps or blocks and uniformly mixed, 0.5h is needed, a standard solution and other reagent solutions needed for detection are prepared, 1h is needed for sample dissolution, corresponding volumes are obtained according to different Si contents, a color developing solution is added, 1h is needed, 1.5h is needed for determination, and 0.5f is needed for drawing and determination of a working curve, and 1.5h is needed, and the data cannot be recovered. By adopting a direct-reading spectrometer, only the detection surface of the praseodymium-neodymium alloy sample needs to be ground into metallic luster, the praseodymium-neodymium alloy sample is directly placed on a spark table for detection, the detection results of Fe, al, mo, si and C5 elements can be reported at one time, and the detection only needs 2 minutes.

Five parts of the drilled praseodymium-neodymium alloy sample are weighed in parallel for chemical analysis, and the relative standard deviation RSD of a detection result is less than 5%; and (3) polishing the surface of the praseodymium-neodymium alloy sample block to obtain metallic luster, detecting 5 different positions of the upper part, the lower part and the middle part of the sample by using a direct-reading spectrometer, wherein the relative standard deviation RSD of a detection result is less than 5%, and the relative error is small compared with a chemical analysis result, and the specific result is shown in a second table.

Meanwhile, a high-frequency-infrared carbon-sulfur instrument is adopted for detecting C, 6 yuan is adopted for each sample, an ICP method is adopted for detecting Fe, 35 yuan is adopted for each sample, and the direct-reading spectrometer can detect various elements at one time, wherein each sample only needs 0.5 yuan.

Compared with the conventional chemical analysis method, the direct-reading spectrum has the advantages of no sample loss, favorable recovery, high detection speed, capability of reducing cost and the like.

TABLE 1 (%)

As can be seen from the table I, the prepared standard sample contains the 5 non-rare earth elements, and the element contents are distributed in a gradient manner with a certain difference, so that the product quality control requirement is met. The normal phenomenon is that some fluctuation occurs as a result of the introduction of raw materials and the loss of smelting in the electrolytic smelting process.

TABLE II (%)

From the second table, it can be seen that, no matter the chemical analysis method or the direct-reading spectroscopy method, the relative standard deviation RSD of the results of the 5 sets of data detected in parallel is less than 5%, which indicates that the prepared sample has good uniformity and meets the quality requirement of the internal control sample established as the standard curve point.

Claims

1. An internal control sample in rare earth metal or alloy detection is characterized in that: the internal control sample is a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80mm and the height of 10-50mm.

2. The internal control sample in the detection of the rare earth metal or the alloy according to claim 1, wherein: the internal control sample is a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-50mm and the height of 10-20mm.

3. The internal control sample in the detection of the rare earth metal or the alloy according to claim 1 or 2, wherein the rare earth metal comprises metals of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium;

the rare earth alloy metal comprises praseodymium-neodymium alloy, lanthanum-cerium alloy, praseodymium-neodymium-dysprosium alloy, praseodymium-neodymium-gadolinium alloy, praseodymium-neodymium-terbium-dysprosium alloy, dysprosium-iron alloy, holmium-iron alloy, gadolinium-iron alloy, neodymium-iron alloy, terbium-iron alloy, yttrium-iron alloy, erbium-iron alloy, rare earth-magnesium alloy and rare earth-aluminum alloy.

4. The internal control sample in the detection of the rare earth metal or the alloy according to claim 1 or 2, wherein: in the internal control sample, the main content of rare earth metal or rare earth alloy is 99.0-99.99%, and the content of non-rare earth is 0.010-1%;

the internal control sample is applied to a spark direct-reading spectrometer for detecting rare earth metals or alloys, the relative standard deviation RSD of a parallel determination result is less than 5 percent, and the requirement of the internal control sample established as a standard curve point is met.

5. The method for preparing the internal control sample in the detection of the rare earth metal or the alloy as claimed in any one of claims 1 to 4, characterized by comprising the following steps:

the first step is as follows: raw material preparation

thirdly, internal control sample surface treatment:

dry grinding with abrasive or machining to the required finish and flatness.

6. The method for preparing internal control samples for detecting rare earth metals and alloys as claimed in claim 5, wherein in said second step, the step of smelting or electrolytic smelting comprises:

b. mixing and smelting rare earth metal or alloy and a proper amount of non-rare earth elements, and controlling the contents of Fe, al, mo and Si in the metal;

c. during the electrolytic smelting of the rare earth oxide, the content of C in the metal is controlled by controlling the temperature and the anode effect time;

d. mixing metal lanthanum (scraps) and rare earth oxide, adding the mixture into a carbon tube furnace, carrying out vacuum reduction distillation to obtain rare earth metal, and controlling the contents of Fe, al, mo and Si in the metal;

e. mixing calcium metal and rare earth fluoride, putting the mixture into a tungsten crucible after mixing, performing vacuum reduction in an intermediate frequency furnace to obtain rare earth metal, and controlling the contents of Fe, al, mo and Si in the metal;

f. putting rare earth oxide into an electrolytic furnace using the same rare earth fluoride and lithium fluoride as molten salt, using a pure iron rod as a cathode, electrolyzing the rare earth oxide to prepare rare earth alloy, controlling the contents of Fe, al, mo and Si in the metal, pouring the rare earth alloy into a mold after the rare earth alloy is finished, cooling and taking out the rare earth alloy or the rare earth alloy to obtain a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80 mm.

7. The method for preparing internal control sample in rare earth metal and alloy detection according to claim 5, wherein, in the third step,

8. The method for preparing the internal control sample in the detection of the rare earth metals and the alloys according to claim 5, further comprising the following steps:

and fourthly, detecting a fixed value:

sampling and detecting the prepared internal control sample, and verifying and testing the uniformity and stability of the internal control sample;

the fifth step: and cutting and forming the fixed value internal control sample to be used as the internal control sample for establishing the standard curve point.

And sixthly, vacuum storage.

9. The method for preparing internal control samples in the detection of rare earth metals and alloys according to claim 8, wherein in the fourth step, the detection result should not exceed the repeatability limit and reproducibility limit specified in the national standard; and drilling a proper amount of metal scraps at the upper, lower and middle positions of the prepared and surface-treated internal control sample, fully mixing, weighing five parts in parallel for chemical analysis, wherein the relative standard deviation RSD of a detection result is less than 5%, and the requirement of the internal control sample established as a standard curve point is met.

10. The method for preparing the internal control sample for the detection of the rare earth metals and the alloys according to claim 8, wherein the cutting in the fifth step is carried out to form the internal control sample which is cut into a cylinder, and the diameter of the internal control sample is 40-80mm, and the height of the internal control sample is 10-50mm.

11. The method for preparing an internal control sample in the detection of rare earth metals or alloys according to claim 10, wherein the method comprises the following steps: the diameter of the internal control sample is 40-50mm, and the height is 10-20mm.

12. The method for preparing internal control samples for rare earth metal and alloy detection according to any one of claims 5 to 11, wherein the amounts of rare earth metal or rare earth alloy and non-rare earth element are determined according to the total amount of internal control samples to be prepared, the ratio of the rare earth metal or rare earth alloy to the non-rare earth element is 100.

13. The method for preparing internal control sample in rare earth metal and alloy detection according to any one of claims 5 to 11, comprising the following steps:

the first step, rare earth metal and its oxide with rare earth content more than 99.9% calculated by RE/REO and rare earth purity more than 99.9% calculated by RE/REO, including yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, praseodymium neodymium dysprosium, praseodymium neodymium gadolinium, doped non-rare earth element purity more than 99.99%, powder or block; rare earth alloys with rare earth purity of more than 99.9 percent calculated by RE, including praseodymium-neodymium alloy, lanthanum-cerium alloy, praseodymium-neodymium-dysprosium alloy, praseodymium-neodymium-gadolinium alloy, praseodymium-neodymium-terbium-dysprosium, dysprosium-iron alloy, holmium-iron alloy, gadolinium-iron alloy, neodymium-iron alloy, terbium-iron alloy, yttrium-iron alloy, erbium-iron alloy, rare earth magnesium alloy, rare earth aluminum alloy and the like, wherein the purity of doped non-rare earth elements is more than 99.99 percent, and the doped non-rare earth elements are in powder or block shape;

secondly, performing mixed melting or electrolytic melting on rare earth metal and compounds thereof or rare earth alloy and compounds thereof and non-rare earth elements to control the non-rare earth content, and preparing an internal control sample, wherein the method comprises the following steps: a. adding rare earth oxide into fluoride of the same rare earth element and lithium fluoride fused salt, taking a tungsten rod or a molybdenum rod or a pure iron rod as a cathode, and controlling the contents of Fe, al, mo and Si in the fused salt; b. mixing and smelting rare earth metal or alloy and a proper amount of non-rare earth elements, and controlling the contents of Fe, al, mo and Si in the metal; c. during the electrolytic smelting of the rare earth oxide, the content of C in the metal is controlled by controlling the temperature and the anode effect time; d. mixing metal lanthanum scraps and rare earth oxide, adding the mixture into a carbon tube furnace, carrying out vacuum reduction distillation to obtain rare earth metal, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in an intermediate frequency furnace, and controlling the contents of Fe, al, mo and Si in the metal; e. mixing calcium metal and rare earth fluoride, putting the mixture into a tungsten crucible after mixing, carrying out vacuum reduction in an intermediate frequency furnace to obtain rare earth metal, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in the intermediate frequency furnace, and controlling the contents of Fe, al, mo and Si in the metal; f. putting rare earth oxide into an electrolytic furnace using the same kind of rare earth fluoride and lithium fluoride as molten salt, using a pure iron rod as a cathode, electrolyzing the rare earth oxide to prepare rare earth alloy, mixing and smelting the obtained rare earth metal and a proper amount of non-rare earth elements in an intermediate frequency furnace, controlling the contents of Fe, al, mo and Si in the metal, pouring the mixture into a mold after the mixture is finished, cooling the mold, taking the mold out, and cutting the mold into a rare earth metal or rare earth alloy cylindrical sample block with the diameter of 40-80mm and the height of 10-50mm.

14. The method for preparing the internal control sample of the rare earth metal and the alloy according to any one of claims 5 to 11, which is characterized by comprising the following steps:

a. putting rare earth oxide into an electrolytic furnace taking rare earth fluoride, lithium fluoride and the like as molten salt according to the weight ratio, melting at the temperature of 1000-1800 ℃ under the condition that the current is 4500-6500A, heating rare earth metal, alloy and non-rare earth metal elements in an intermediate frequency furnace with the heating power of 80-150 KW, preserving the heat for 20-60 min to ensure complete melting of materials, and refining the melt for 10-40 min at the temperature of 1100-1600 ℃;

the fourth step: and (3) fixed value detection: sampling and detecting the prepared internal control sample, and verifying and testing the uniformity and stability of the internal control sample;

the fifth step: and cutting the internal control sample with a fixed value into a cylinder, wherein the diameter of the cylinder is 40-80mm, and the height of the cylinder is 10-50mm, and the cylinder is used as the internal control sample for establishing a standard curve point.

15. Use of the internal control sample according to claims 1-4 or the internal control sample prepared by the preparation method according to claims 5-14 in detection of rare earth metals and alloys.

16. The use of the internal control sample according to claim 15 for the detection of rare earth metals and alloys, wherein the use is for the detection of non-rare earth impurity elements in rare earth metals and alloys using direct-reading spectroscopy.

17. The use of an internal control sample in the detection of rare earth metals and alloys according to claim 16, wherein the rare earth metals include yttrium metal, lanthanum metal, cerium metal, praseodymium metal, neodymium metal, samarium metal, europium metal, gadolinium metal, terbium metal, dysprosium metal, holmium metal, erbium metal, thulium metal, ytterbium metal, lutetium metal;

18. The use of the internal control sample according to claim 17 for the detection of rare earth metals and alloys, wherein said detection comprises the steps of: metalLab32.Exe → database → input incontinence sample data → F4 calibration → excitation incontinence sample → new program → F2 analysis → selection of analysis line → establishment of working curve → analysis program naming → STD calibration program naming → F8 standardization → curve correction → F7 program → sample analysis;

the direct-reading spectrometer adopts atomic emission spectrometry, each element in a sample is directly gasified from a solid state and excited by high temperature of electric sparks to emit characteristic spectral lines of each element, the intensity of the emission spectral line of each element is in direct proportion to the content of the element in the sample, the emission spectral line is split by a grating to form spectra arranged according to wavelength, the characteristic spectral lines of the elements are emitted into respective photomultiplier tubes through an emergent slit, optical signals are converted into electric signals, the electric signals are integrated, analog-to-digital converted by a control and measurement system of the instrument, and then the electric signals are processed by a computer, and the percentage content of each element is printed; firstly, double clicking MetalLab32.exe, entering a database, selecting an internal control sample, newly establishing an internal control sample name, inputting an element name and content, and determining; returning to an F4 calibration interface, clicking an internal control sample to excite, storing data, and naming a newly-built program; returning to the F2 analysis interface, selecting the wavelength of the element to be added in the channel in the newly-built program, selecting an analysis line, establishing a working curve, storing, naming the analysis program of the established matrix and storing as an STD calibration program at the same time; returning to the F8 analysis interface, clicking the STD calibration program, exciting the internal control sample, and executing global standardization; and finally returning to the F7 program interface, clicking the established analysis program of the matrix, and after type calibration, starting sample detection and analysis.

19. The use of the internal control sample in the detection of rare earth metals and alloys according to claim 17, comprising the steps of:

establishing a standard curve on a spark direct-reading spectrometer; respectively exciting internal control samples with known content to obtain the spectral intensity of each element, making a standard curve according to the intensity ratio of each element to the matrix element and the content of the corresponding element, generally fitting by adopting a quadratic curve or a cubic curve, and performing element interference correction on the curve if necessary to ensure the accuracy of a detection result; the standard curve is a lasting curve, the curve does not need to be drawn again before a sample is analyzed each time, only the designated internal control sample is needed to carry out intensity correction and/or content correction on the curve, a corrected working curve and correction coefficients of all elements are obtained, the correction coefficients are about 1.0, and accurate and reliable test results of the established working curve can be guaranteed under the current state condition of the instrument.

20. The use of the internal control sample in the detection of rare earth metals and alloys according to claim 19, comprising the steps of:

21. The use of the internal control sample in the detection of rare earth metals and alloys according to claim 20, wherein the detection is performed for 2 minutes on average, the detection results of multiple elements can be reported at one time, the product is free from damage and loss in the detection process, and the rare earth metals and alloys can be recycled after the detection.