WO2024027327A1 - Rare earth oxide standard sample, and preparation process therefor - Google Patents

Abstract

The invention relates to the technical field of standard sample preparation, and in particular to a rare earth oxide standard sample and a preparation method therefor. The rare earth oxide standard sample of the present invention comprises a uniform mixture of rare earth oxide and sodium chloride; the rare earth oxide in the rare earth oxide standard sample is 28-42% by mass, and the rare earth oxide comprises lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide; the lanthanum oxide comprises 0.1%-15%, the cerium oxide comprises 0.2%-28%, the praseodymium oxide comprises 0.1%-8%, and the neodymium oxide comprises 0.5%-32%. Using sodium chloride as a diluent effectively reduces the total concentration of rare earth, allows for accurately controlling the content ranges of standard values, and ensures that the standard values of the standard sample are consistent with the content of the total amount of rare earth of an actual product (rare earth carbonate and rare earth chloride), thereby further accurately controlling product quality; moreover, the standard sample has relatively high uniformity and stability.

Description

Rare earth oxide standard sample and preparation method thereof Technical field

The present invention relates to the technical field of standard sample preparation, and specifically to a rare earth oxide standard sample and a preparation method thereof.

Background technique

Based on the standard analysis method of rare earth oxides and the social role of standard samples, the current rare earth standard samples have the problem that the standard value and distribution ratio of the total amount of rare earths are significantly different from the actual products (rare earth carbonate and rare earth chloride). From the analysis of the in-depth development needs of my country's rare earth standards, the calibration needs of high-end testing equipment, the development of the rare earth industry and the international standardization needs, it is of practical significance to prepare the standard value of the total rare earth content of the rare earth oxide standard sample.

The fixed value components of existing rare earth oxide standard samples are almost all based on single rare earth oxides with relatively high purity, and there are no mixed oxides with binary or multicomponent oxides that can control the total amount of rare earths. In the process of promoting the application of rare earth oxide standard samples, there are problems such as limited types, fewer fixed-value elements, and the range of component content cannot cover actual products. The rare earth industry is in urgent need of such standard samples to guide testing and production.

In view of this, the present invention is proposed.

Contents of the invention

An object of the present invention is to provide a rare earth oxide standard sample to solve the problem that the fixed component of the rare earth oxide standard sample in the prior art does not have a total rare earth value, and the component content range cannot cover the actual product, such as rare earth carbonate, chloride There is a technical problem that the rare earth and other important rare earth products cannot use the product itself as a candidate to prepare standard samples due to unstable properties. By using sodium chloride as a diluent, the rare earth oxide standard sample of the present invention can effectively reduce the total rare earth concentration, accurately control the content range of the standard value, and meet the requirements of uniformity and stability.

Another object of the present invention is to provide a method for preparing the rare earth oxide standard sample. The method is simple and easy to implement. The raw materials are ground and mixed to meet the particle size range requirements of the rare earth oxide.

In order to achieve the above objects of the present invention, the following technical solutions are adopted:

The rare earth oxide standard sample includes a homogeneous mixture of rare earth oxide and sodium chloride; in the rare earth oxide standard sample, the rare earth oxide is 28% to 42% in terms of mass percentage;

The rare earth oxides include lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide;

The lanthanum oxide is 0.1% to 15%, the cerium oxide is 0.2% to 28%, the praseodymium oxide is 0.1% to 8%, and the neodymium oxide is 0.5% to 32%.

In one embodiment, the particle size D10 of the rare earth oxide standard sample is 0.1 to 1 μm;

The particle size D50 of the rare earth oxide standard sample is 0.5-3 μm;

The particle size D90 of the rare earth oxide standard sample is 1 to 8 μm.

In one embodiment, the rare earth oxide is lanthanum cerium oxide or praseodymium neodymium oxide.

In one embodiment, in the rare earth oxide standard sample, the lanthanum cerium oxide is 38% to 42% in terms of mass percentage;

The mass percentages of each component in the lanthanum cerium oxide of the rare earth oxide standard sample are respectively: lanthanum oxide is 13% to 15%, cerium oxide is 24% to 28%, and praseodymium oxide is 0.1% to 0.4%. Neodymium oxide is 0.5% to 1%.

In one embodiment, in the lanthanum cerium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.75-2.

In one embodiment, in the lanthanum cerium oxide, the mass ratio of neodymium oxide and praseodymium oxide is 2.5-5.

In one embodiment, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 28% to 32% in terms of mass percentage;

The mass percentages of each component in the praseodymium and neodymium oxide of the rare earth oxide standard sample are respectively: 0.1% to 0.3% for lanthanum oxide, 0.2% to 0.5% for cerium oxide, and 6% to 8% for praseodymium oxide. Neodymium oxide is 21% to 24%;

In one embodiment, in the praseodymium and neodymium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.65-2.

In one embodiment, in the praseodymium and neodymium oxide, the mass ratio of neodymium oxide and praseodymium oxide is 2.9 to 3.6.

In one embodiment, the rare earth oxide standard sample also includes trace elements, and the content of the trace elements is 0.5 to 50 ppm;

The trace elements include K, Ca, Fe, Cu and Zn.

The preparation method of the rare earth oxide standard sample includes the following steps:

Grind the mixture of rare earth oxide raw materials and sodium chloride raw materials, and then mix them;

The rare earth oxide raw materials include lanthanum oxide raw materials, cerium oxide raw materials, praseodymium oxide raw materials and neodymium oxide raw materials.

In one embodiment, the method for preparing a mixture of rare earth oxide raw materials and sodium chloride raw materials includes: premixing the rare earth oxide raw materials and sodium chloride raw materials;

The premixing time is 2 to 3 hours.

In one embodiment, the grinding time ranges from 170 to 200 seconds.

In one embodiment, the mixing time is 170 to 190 minutes.

In one embodiment, the sodium chloride raw material is high-grade pure sodium chloride.

In one embodiment, the method for preparing a rare earth oxide standard sample further includes: performing uniformity testing and stability testing on the rare earth oxide standard sample.

Compared with the prior art, the beneficial effects of the present invention are:

(1) By using sodium chloride as the diluent, the rare earth oxide standard sample of the present invention can effectively reduce the total rare earth concentration, accurately control the content range of the standard value, and ensure that the standard value of the standard sample is consistent with the total rare earth content of the actual product. , to further accurately control product quality; the rare earth oxide standard sample has excellent uniformity and stability.

(2) The rare earth oxide standard sample of the present invention can effectively meet the quality control of production and research and development, and gradually improve the standard sample series; the standard sample meets the strategic layout requirements of the rare earth industry, innovates the types of rare earth standard sample preparation, and provides a basis for building new rare earth materials. The testing and evaluation system plays an important role in promoting the development of new rare earth material technology, standardizing the quality of rare earth products, and monitoring the testing of rare earth products.

(3) The preparation method of the rare earth oxide standard sample in the present invention is simple and easy. By grinding and mixing each raw material, the particle size range requirements of the rare earth oxide can be achieved, and the uniformity and stability are excellent.

Description of the drawings

In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the drawings that need to be used in the description of the specific implementations or the prior art will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a flow chart for the preparation of a rare earth oxide standard sample according to one embodiment of the present invention;

Figure 2 is a scanning electron microscope image of the rare earth oxide standard sample in Example 1 of the present invention at an EHT of 3KV and a magnification of 1000 times;

Figure 3 is a scanning electron microscope image of the rare earth oxide standard sample in Example 1 of the present invention at an EHT of 20KV and a magnification of 500 times;

Figure 4 is a scanning electron microscope image of the rare earth oxide standard sample in Example 4 of the present invention at an EHT of 3KV and a magnification of 1000 times;

Figure 5 is a scanning electron microscope image of the rare earth oxide standard sample in Example 4 of the present invention at an EHT of 20KV and a magnification of 500 times;

Figure 6 is a particle size distribution curve of mixed (lanthanum, cerium, praseodymium, neodymium) rare earth oxides;

Figure 7 is a scanning electron microscope image of mixed (lanthanum, cerium, praseodymium, neodymium) rare earth oxides;

Figure 8 is a particle size distribution curve diagram of the rare earth oxide standard sample in Example 1;

Figure 9 is a particle size distribution curve diagram of the rare earth oxide standard sample in Example 4;

Figure 10 shows the comprehensive thermal analysis curve of mixed rare earth oxides, including thermogravimetric analysis (TG) curve and differential scanning calorimetry (DSC) curve;

Figure 11 is the thermal analysis curve of the rare earth oxide standard sample in Example 1, including a thermogravimetric analysis (TG) curve and a differential scanning calorimetry (DSC) curve;

Figure 12 is the thermal analysis curve of the rare earth oxide standard sample in Example 4, including a thermogravimetric analysis (TG) curve and a differential scanning calorimetry (DSC) curve;

Figure 13 is a physical diagram of the lanthanum cerium oxide standard sample of the present invention;

Figure 14 is a physical diagram of the praseodymium and neodymium oxide standard sample of the present invention;

Figure 15 is a packaging diagram of the lanthanum cerium oxide standard sample of the present invention;

Figure 16 is a packaging diagram of the praseodymium and neodymium oxide standard sample of the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

According to one aspect of the present invention, the present invention relates to a rare earth oxide standard sample, including a homogeneous mixture of rare earth oxide and sodium chloride; in terms of mass percentage, in the rare earth oxide standard sample, the rare earth oxide is 28%～42%;

The rare earth oxides include lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide;

In terms of mass percentage, in the rare earth oxide standard sample, the lanthanum oxide is 0.1% to 15%, the cerium oxide is 0.2% to 28%, the praseodymium oxide is 0.1% to 8%, and the oxide Neodymium is 0.5% to 32%.

The rare earth oxide standard sample of the present invention is doped with sodium chloride in the rare earth oxide, and uses sodium chloride as a diluent, thereby accurately controlling the total amount of rare earth oxides in the rare earth oxide standard sample, making the rare earth standard sample more effective. Wide applicability.

In one embodiment, the particle size D10 of the rare earth oxide standard sample is 0.1 to 1 μm;

The particle size D50 of the rare earth oxide standard sample is 0.5-3 μm;

The particle size D90 of the rare earth oxide standard sample is 1 to 8 μm.

In one embodiment, the particle size D10 of the rare earth oxide standard sample includes, but is not limited to, 0.2 μm, 0.35 μm, 0.47 μm, 0.5 μm, 0.63 μm, 0.75 μm, 0.88 μm, 0.96 μm or 1 μm. In one embodiment, the particle size D50 of the rare earth oxide standard sample includes but is not limited to 0.5 μm, 0.86 μm, 0.9 μm, 1 μm, 1.24 μm, 1.57 μm, 1.81 μm, 2 μm, 2.24 μm, and 2.55 μm. , 2.73μm, 2.9μm or 3μm. In one embodiment, the particle size D90 of the rare earth oxide standard sample includes but is not limited to 1 μm, 1.56 μm, 1.8 μm, 2 μm, 2.54 μm, 3 μm, 3.05 μm, 3.58 μm, 4 μm, 4.25 μm, 4.8 μm, 5μm, 5.54μm, 6μm, 7μm or 8μm.

By further controlling the particle size range of rare earth oxides and sodium chloride, we ensure that the rare earth oxide standard samples have better uniformity and stability.

The diluent is based on sodium salt. The chemical properties of Na ₂ SO ₄ , Na ₂ CO ₃ , NaHCO ₃ and NaCl were analyzed respectively. Combined with their stability after mixing with rare earth oxides, the suitability of the diluent was judged. .

NaCl (Sodium chloride), looks like white crystals, has good stability, is neutral, and has a melting point of 801°C. It is used in industry to make soda ash and caustic soda and in ore smelting. It can be used in daily life as condiments. It is non-toxic and highly safe. . Therefore, the present invention selects NaCl as the diluent from the perspective of stable chemical properties and non-toxicity to control the total amount of rare earths.

Na ₂ SO ₄ (Sodium sulfate) is a monoclinic crystal system with short columnar crystals, colorless, transparent, neutral, easily soluble in water, and low toxicity. The normal state is white crystal or powder, which is water-absorbent and can easily form 7 or 10 crystal hydrates, with a melting point of 884°C. Although Na ₂ SO ₄ is stable in nature, it is easily hydrated in humid air and converted into powdered hydrous sodium sulfate to cover the surface. When mixed with rare earth oxides, the stability of the standard sample will be reduced.

Na ₂ CO ₃ (Sodium carbonate) is a white powder that is easily soluble in water, alkaline and non-toxic. It is easy to weather in dry air and has water absorption. After absorbing water, it will form 10 crystal hydrates with a melting point of 851°C. It decomposes at about 1200℃ and reacts with CO ₂ and H ₂ O to form NaHCO ₃ . _Na2CO3 also has poor stability as _a rare earth oxide diluent due to its water absorption and reaction with _CO2 .

NaHCO ₃ (Sodium Bicarbonate) is white powder or monoclinic crystalline powder, easily soluble in water, alkaline, non-toxic, and decomposes slowly when heated or in humid air. The decomposition temperature is 270°C. The reaction starts to produce CO ₂ at approximately 50°C, and all becomes Na ₂ CO ₃ at 100°C. NaHCO ₃ is not only easy to absorb water, but also has a relatively low decomposition temperature. Compared with Na ₂ SO ₄ and Na ₂ CO ₃ , it is less suitable to be used as a diluent.

The particle size range and the chemical properties of the material itself are key indicators that reflect the uniformity of the standard sample. After the diluent is mixed with the rare earth oxide, a loose, non-agglomerated powder is formed, and its properties do not affect the physical mixing of the standard sample. The particle size range of each component has a great influence on the uniformity of the rare earth oxide standard sample; if the particle size range of each component is wide, the standard sample particles will be very different, which will easily lead to the segregation of the component elements; if the particle size range is small, material interstitiality will occur. Agglomeration and entrapment phenomena can easily lead to the concentration of rare earth oxides in large areas, so reasonable control of the particle size range of standard samples is the key to uniformity.

In one embodiment, the rare earth oxide standard sample further includes trace elements, and the content of the trace elements is 0.5 to 50 ppm; the trace elements include K, Ca, Fe, Cu and Zn. That is, the rare earth oxide standard sample of the present invention includes rare earth oxide, sodium chloride and trace elements.

In one embodiment, in terms of mass percentage, in the rare earth oxide standard sample, the rare earth oxide includes but is not limited to 29%, 30%, 31%, 32%, 33%, 34%, 35% %, 36%, 37%, 38%, 39%, 40%, 41% or 42%.

In one embodiment, in terms of mass percentage, the sodium chloride in the rare earth oxide standard sample is 58% to 72%. In mass percentage, sodium chloride includes, but is not limited to, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70% or 71 %.

In one embodiment, the rare earth oxide is lanthanum cerium oxide or praseodymium neodymium oxide.

In one embodiment, in terms of mass percentage, the lanthanum cerium oxide in the rare earth oxide standard sample is 38% to 42%. In one embodiment, each of the lanthanum cerium oxides The mass percentages of the components in the rare earth oxide standard sample are: lanthanum oxide is 13% to 15%, cerium oxide is 24% to 28%, praseodymium oxide is 0.1% to 0.4%, and neodymium oxide is 0.5% to 1%.

In one embodiment, in terms of mass percentage, in the rare earth oxide standard sample, the lanthanum cerium oxide is 38%, 38.5%, 39%, 39.5%, 40%, 40.5%, 41%, 41.5 % or 42%. The mass percentage of each component in the lanthanum cerium oxide in the rare earth oxide standard sample is specifically: lanthanum oxide includes but is not limited to 13%, 13.2%, 13.5%, 14%, 14.5%, 14.7%, 14.8% or 14.9%; cerium oxide includes but is not limited to 24%, 24.5%, 25%, 25.3%, 25.5%, 26%, 26.5%, 27%, 27.5% or 28%; praseodymium oxide includes but is not limited to 0.1% , 0.12%, 0.15%, 0.17%, 0.2%, 0.22%, 0.25%, 0.27%, 0.3%, 0.32%, 0.34%, 0.35%, 0.36%, 0.39% or 0.4%; neodymium oxide includes but is not limited to 0.5%, 0.52%, 0.55%, 0.57%, 0.6%, 0.62%, 0.65%, 0.67%, 0.69%, 0.7%, 0.75%, 0.78%, 0.8%, 0.82%, 0.85%, 0.9%, 0.95% or 1%.

In one embodiment, in the lanthanum cerium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.75 to 2, such as 1.76, 1.78, 1.8, 1.82, 1.84, 1.85, 1.86, 1.87, 1.9, 1.93, 1.95 Or 1.97 etc. In one embodiment, in the lanthanum cerium oxide, the mass ratio of neodymium oxide and praseodymium oxide is 2.5 to 5, such as 2.5, 2.7, 3, 3.5, 3.8, 4, 4.2, 4.5, 4.7 or 5, etc.

In one embodiment, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 28% to 32% in terms of mass percentage. In one embodiment, the mass percentage of each component in the praseodymium and neodymium oxide in the rare earth oxide standard sample is respectively: 0.1% to 0.3% for lanthanum oxide, 0.2% to 0.5% for cerium oxide, and 0.2% to 0.5% for praseodymium oxide. It is 6% to 8%, and neodymium oxide is 21% to 24%.

In one embodiment, in terms of mass percentage, in the rare earth oxide standard sample, the praseodymium and neodymium oxides include, but are not limited to, 28%, 28.5%, 29%, 29.5%, 30%, 30.5%, 31%, 31.5% or 32%. The mass percentage of each component in the praseodymium and neodymium oxide in the rare earth oxide standard sample is specifically: lanthanum oxide includes but is not limited to 0.1%, 0.12%, 0.15%, 0.17%, 0.2%, 0.22%, 0.25% , 0.27% or 0.3%; cerium oxide includes but is not limited to 0.2%, 0.25%, 0.27%, 0.3%, 0.32%, 0.35%, 0.37%, 0.4%, 0.42%, 0.45%, 0.48% or 0.5%, praseodymium oxide includes but is not limited to 6% to 8%, neodymium oxide includes but is not limited to 21%, 21.5%, 22%, 22.5%, 23%, 23.5% or 24%.

In one embodiment, in the praseodymium and neodymium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.65 to 2, such as 1.65, 1.68, 1.7, 1.72, 1.75, 1.78, 1.8, 1.85, 1.9, 1.95 or 2 wait. In one embodiment, in the praseodymium and neodymium oxide, the mass ratio of neodymium oxide and praseodymium oxide is 2.9 to 3.6, such as 3, 3.1, 3.2, 3.3, 3.4 or 3.5, etc.

In one embodiment, in the lanthanum cerium oxide standard sample, the ratios of lanthanum oxide and cerium oxide are controlled at 35% and 65% respectively, that is, the mass ratio of cerium oxide and lanthanum oxide is approximately 1.86. In one embodiment, in the standard sample of praseodymium and neodymium oxide, the proportions of praseodymium oxide and neodymium oxide are controlled at 25% and 75% respectively, that is, the mass ratio of neodymium oxide and praseodymium oxide is 3. As a standard product with characteristic values, it is closer to the actual product ingredients and has better quality control effect.

According to another aspect of the present invention, the present invention also relates to a method for preparing the rare earth oxide standard sample, which includes the following steps:

The mixture of rare earth oxide raw materials and sodium chloride raw materials is ground and then mixed; the rare earth oxide raw materials include lanthanum oxide raw materials, cerium oxide raw materials, praseodymium oxide raw materials and neodymium oxide raw materials.

In the present invention, rare earth oxide raw materials and sodium chloride raw materials are ground and then mixed. The method is simple and easy to implement, and the obtained standard sample has excellent uniformity and stability. The standard sample preparation method can realize the quality control and calibration of instruments during the testing process of rare earth products such as rare earth carbonate and rare earth chloride. It is mainly used for the evaluation and calibration of standard methods for determining the total amount of rare earths by gravimetric method and ICP-OES method. It meets the problem that products such as rare earth carbonate and rare earth chloride cannot directly prepare standard samples due to their unstable properties.

In one embodiment, the preparation method of the mixture of the rare earth oxide raw material and the sodium chloride raw material includes: premixing the rare earth oxide raw material and the sodium chloride raw material; the premixing The time is 2~3h.

In one embodiment, the grinding time ranges from 170 to 200 seconds. In one embodiment, the time of the grinding process includes, but is not limited to, 170s, 172s, 175s, 180s, 182s, 185s, 187s, 190s, 195s, 197s or 200s. The control of the particle size range depends on the time of the grinding process. If the time is short, the particle size range is wide, and the standard sample particles are greatly different, it is easy to cause the segregation of component elements; if the grinding process is long and the particle size range is small, agglomeration and entrapment between substances will occur. , it is easy to cause the concentration of rare earth oxides in a large area; therefore, the particle size range of the standard sample can be reasonably controlled by using appropriate grinding time.

In one embodiment, the mixing time is 170 to 190 minutes. In one embodiment, the time of the mixing process includes but is not limited to 171min, 172min, 173min, 174min, 175min, 176min, 177min, 178min, 179min, 180min, 181min, 182min, 185min, 187min or 190min. The present invention can ensure sufficient mixing of each component by adopting appropriate mixing processing time, so that the standard sample can obtain higher uniformity.

In one embodiment, the purity of the lanthanum oxide raw material, cerium oxide raw material, praseodymium oxide raw material and neodymium oxide raw material are all above 4N level. In one embodiment, the sodium chloride raw material is high-grade pure sodium chloride.

In one embodiment, the preparation method of the rare earth oxide standard sample further includes the following steps: conducting uniformity detection and stability detection on the rare earth oxide standard sample; After the stability is qualified, a fixed value test is performed. In one embodiment, at least 6 detection mechanisms can perform fixed-value detection, provide at least 8 sets of fixed-value detection data, and perform statistics on the results of standard values.

In one embodiment, the uniformity detection uses glow discharge mass spectrometry (GD-MS). GD-MS is an analytical method that uses a glow discharge source as an ion source to connect to a mass spectrometer instrument for mass spectrometry measurement. Inert gas (argon) is passed into the glow discharge battery, an electric field is applied between the cathode and anode, and the inert gas is broken down and ionized. Positive ions accelerate and impact the sample surface as the cathode under the action of the electric field. The surface atoms are sputtered and separated from the sample into the glow discharge plasma. After being ionized in the plasma, they are introduced into the mass spectrometer. The separated ions The beam is collected and detected by the detector. The computer automatically calculates the mass fraction of each element to be measured based on the "standard relative sensitivity factor" in the instrument software. According to the uniformity requirements of the standard sample, the GD-MS method was used to study the uniformity of the standard sample. The detection principles of GD-MS and ICP-MS are the same, but GD-MS has the following advantages: 1) Ability to analyze solids directly, quickly, and with multiple elements; 2) Uniform response for most elements; 3) Sub-ppb detection limit; 4) Simplicity of mass spectrometry; 5) Easy operation. These special characteristics make GD-MS technology feasible for samples that exist in complex solid matrices and are difficult to dissolve, and can be used to prove the homogeneity of the sample to be tested.

In one embodiment, the uniformity detection specifically includes: According to the requirements of GB/T 15000 "Standard Sample Work Guide" and YS/T 409-2012 "Technical Specifications for Standard Samples for Analysis of Non-ferrous Metal Products", the overall number of units When N<1000, 2% to 3% will be selected, no less than 15. And according to the random number table, 15 bottles of samples were selected for uniformity testing. Select 15 groups of equal amounts of the rare earth oxide standard samples, measure the content of each trace element in each group of standard samples, and calculate the relative standard deviation of the content of the same trace element in each group. In one embodiment, different personnel of the at least six detection institutions perform the fixed value detection at different times. In one embodiment, the total rare earth content of the standard sample is measured using GB/T 24635-2020; the rare earth distribution is measured using GB/T 16484.3-2009. In one embodiment, a qualified laboratory is used in the fixed value detection process, and a certified standard solution is used to accurately assign values to the total amount of rare earths, lanthanum, cerium, praseodymium, and neodymium in the standard sample.

In a preferred embodiment, a method for preparing a rare earth oxide standard sample for controlling the standard value of total rare earth content, as shown in Figure 1, includes the following steps:

1. Design of rare earth oxide standard sample composition:

Raw materials: sodium chloride and rare earth oxides (lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide);

1. Composition design of lanthanum cerium oxide standard sample: in terms of mass percentage, the rare earth oxide In the standard sample, the lanthanum cerium oxide is 38% to 42%; the mass percentage of each component in the lanthanum cerium oxide to the rare earth oxide standard sample is: lanthanum oxide is 13% to 15%, and cerium oxide is 13% to 15%. is 24% to 28%, praseodymium oxide is 0.1% to 0.4%, and neodymium oxide is 0.5% to 1%; in the lanthanum cerium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.75 to 2, and the mass ratio of neodymium oxide and lanthanum oxide is 1.75-2. The mass ratio of praseodymium is 2.5 to 5;

2. Composition design of the praseodymium and neodymium oxide standard sample: in terms of mass percentage, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 28% to 32%; each component in the praseodymium and neodymium oxide The mass percentage of the rare earth oxide standard sample is: lanthanum oxide is 0.1% to 0.3%, cerium oxide is 0.2% to 0.5%, praseodymium oxide is 6% to 8%, and neodymium oxide is 21% to 24%; the lanthanum Among cerium oxides, the mass ratio of cerium oxide to lanthanum oxide is 1.65 to 2, and the mass ratio of neodymium oxide to praseodymium oxide is 2.9 to 3.6.

2. Preparation of rare earth oxide standard samples

Select high-grade pure sodium chloride with uniform particle size and rare earth oxides above 4N grade to be premixed, grind for 175 to 182 seconds, and then mix for 175 to 185 minutes to obtain a rare earth oxide standard sample.

3. Detection of rare earth oxide standard samples

The particle size and micromorphology of the obtained rare earth oxide standard sample were studied to determine the composition design results and uniformity characterization of the sample, and then a preliminary uniformity test was conducted. The basis for the preliminary uniformity test was the standard deviation and method of 7 tests. Allowed differences between laboratories are compared when When , the initial uniformity inspection is considered to be qualified; when When, the initial inspection of uniformity failed. After passing the initial inspection, conduct uniformity and stability inspections, and consider the combined verification of multiple statistical methods. After the uniformity test and stability test have passed the requirements of the technical specifications, 6 qualified laboratories will be selected to carry out fixed value testing at different times, different methods and different personnel, and at least 8 sets of data will be given for statistical setting of the results. The setting process requires each laboratory to use certified reference materials as standard curves in the testing process. The testing equipment used must be verified or calibrated. The testing personnel must be certified and perform repeated tests to ensure the traceability of the setting results. . According to the technical specifications for standard samples for non-ferrous metal product analysis YS/T409-2012 and the standard sample work guidelines GB/T15000.3-2008, the uniformity test is carried out. Value and data processing.

Further description will be given below with reference to specific embodiments and drawings.

Example 1

Rare earth oxide standard sample, including a homogeneous mixture of lanthanum cerium oxide and sodium chloride; in terms of mass percentage, in the lanthanum cerium oxide standard sample, lanthanum cerium oxide is 40%, of which lanthanum oxide is 13.8%, and cerium oxide is 13.8%. is 25.4%, praseodymium oxide is 0.2%, and neodymium oxide is 0.6%; among them, the particle size D10 of the rare earth oxide standard sample is 0.251 μm; the particle size D50 of the rare earth oxide standard sample is 0.707 μm; the rare earth oxide standard The particle size D90 of the sample is 1.91 μm.

The preparation method of the rare earth oxide standard sample in this embodiment includes the following steps:

Mix the high-grade pure sodium chloride raw material and the rare earth oxide raw material, grind for 3 minutes, and then mix for 3 hours to obtain the rare earth oxide standard sample.

Example 2

The rare earth oxide standard sample includes a homogeneous mixture of lanthanum cerium oxide and sodium chloride; in terms of mass percentage, in the rare earth oxide standard sample, lanthanum cerium oxide is 38%, of which lanthanum oxide is 13%, and lanthanum oxide is 13%. Cerium is 24.4%, praseodymium oxide is 0.1%, and neodymium oxide is 0.5%; among them, the particle size D10 of the rare earth oxide standard sample is 0.292 μm; the particle size D50 of the rare earth oxide standard sample is 0.855 μm; the rare earth oxide The particle size D90 of the standard sample is 2.36 μm. The preparation method of the rare earth oxide standard sample in this example is the same as in Example 1.

Example 3

The rare earth oxide standard sample includes a homogeneous mixture of lanthanum cerium oxide and sodium chloride; in terms of mass percentage, in the rare earth oxide standard sample, lanthanum cerium oxide is 42%, of which lanthanum oxide is 15%, and lanthanum oxide is 15%. Cerium is 26.6%, praseodymium oxide is 0.3%, and neodymium oxide is 0.1%; among them, the particle size D10 of the rare earth oxide standard sample is 0.311 μm; the particle size D50 of the rare earth oxide standard sample is 0.880 μm; the particle size D90 of the rare earth oxide standard sample is 6.96 μm. The preparation method of the rare earth oxide standard sample in this example is the same as in Example 1.

Example 4

The rare earth oxide standard sample includes a homogeneous mixture of praseodymium and neodymium oxides and sodium chloride; in terms of mass percentage, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 30%, of which lanthanum oxide is 0.2%, and lanthanum oxide is 0.2%. Cerium is 0.4%, praseodymium oxide is 7.3%, and neodymium oxide is 22.1%; among them, the particle size D10 of the rare earth oxide standard sample is 0.269 μm; the particle size D50 of the rare earth oxide standard sample is 0.910 μm; the rare earth oxide The particle size D90 of the standard sample is 5.51 μm.

The preparation method of the praseodymium and neodymium oxide standard sample in this embodiment includes the following steps:

Mix the high-grade pure sodium chloride raw material and the rare earth oxide raw material, grind for 3 minutes, and then mix for 3 hours to obtain the rare earth oxide standard sample.

Example 5

The rare earth oxide standard sample includes a homogeneous mixture of praseodymium and neodymium oxides and sodium chloride; in terms of mass percentage, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 28%, of which lanthanum oxide is 0.3%, and lanthanum oxide is 0.3%. Cerium is 0.5%, praseodymium oxide is 6%, and neodymium oxide is 21.2%. The preparation method of the rare earth oxide standard sample in this example is the same as that in Example 4.

Example 6

Rare earth oxide standard sample, including a homogeneous mixture of praseodymium and neodymium oxide and sodium chloride; in terms of mass percentage, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 32%, among which, lanthanum oxide is 0.1%, and cerium oxide is 0.1%. It is 0.3%, praseodymium oxide is 8%, and neodymium oxide is 23.6%. The preparation method of the rare earth oxide standard sample in this example is the same as that in Example 4.

Example 7

The preparation method of rare earth oxide standard samples includes: (1) Raw material preparation: select 6000g of high-grade pure sodium chloride with uniform particle size, accurately weigh 1380g of lanthanum oxide, 2540g of cerium oxide, and praseodymium oxide 20g, neodymium oxide 60g; (2) Premix each component in step (1), the premixing time is 2h, and then use a grinder to grind for 3min, grinding 150g in each round; grind the ground material Further mix using a mixer, the mixing time is 3 hours, and a rare earth oxide standard sample is obtained, as shown in Figure 13. The rare earth oxide standard sample prepared in this example is packaged, as shown in Figure 15.

Example 8

The preparation method of rare earth oxide standard samples includes: (1) Raw material preparation: select 7000g of high-grade pure sodium chloride with uniform particle size, accurately weigh 20g of lanthanum oxide, 40g of cerium oxide, 730g of praseodymium oxide, and 2210g of neodymium oxide; (2 ) Premix each raw material in step (1), the premixing time is 2 hours, and then grind it with a grinder for 3 minutes, grinding 150g in each round; further mix the ground materials with a mixer, and mix The homogenization time is 3h, and a rare earth oxide standard sample is obtained, as shown in Figure 14. The rare earth oxide standard sample prepared in this example is packaged, as shown in Figure 16.

The particle size and micromorphology of the rare earth oxide standard samples in each embodiment were studied to determine the composition design results and uniformity characterization of the samples, and then a preliminary uniformity inspection was conducted. After passing the initial inspection, the uniformity and stability inspection was performed. Many considerations were taken into consideration. Combined verification of two statistical methods; the uniformity detection adopts glow discharge mass spectrometry; the uniformity detection specifically includes: randomly selecting 15 equal groups of standards from different parts of the rare earth oxide standard sample, and measuring each group of standards The content of each trace element in the product is calculated, and the average value, standard deviation and relative standard deviation of the same trace element in each group are calculated; in each group, the relative standard deviation of the same trace element content meets the allowable fluctuation range of trace element determination. .

Experimental example

1. Scanning electron microscope (SEM) image of rare earth oxide standard sample

Figure 2 shows the rare earth oxide standard sample in Example 1 of the present invention when the EHT is 3KV, enlarged Scanning electron microscope image under the condition of 1000 times; Figure 3 is the scanning electron microscope image of the rare earth oxide standard sample in Example 1 of the present invention at an EHT of 20KV and magnification of 500 times; Figure 4 is the rare earth oxide standard sample in Example 4 of the present invention The scanning electron microscope image of the oxide standard sample at an EHT of 3KV and a magnification of 1000 times; Figure 5 is a scanning electron microscope image of the rare earth oxide standard sample in Example 4 of the present invention at an EHT of 20KV and a magnification of 500 times. See Figure 2, Figure 3, Figure 4, and Figure 5. The EHT is 3KV. Under the condition of magnification 1000 times, the SEM micromorphology of the standard sample is observed in SE2 mode. It shows polygonal granules with uniform particle size. The EHT is 20KV. Under the magnification 500 times, the SEM micromorphology of the standard sample is observed. Under multiple conditions, the SEM micromorphology of the standard sample was observed in HDBSD mode, and particles with different light and dark colors were formed, which were sodium chloride particles and rare earth oxide particles respectively. The bright particles were rare earth oxides and the dark particles were sodium chloride crystals. In the case of micro areas, SEM images can prove that the two types of materials are evenly distributed.

2. Particle size distribution curve of rare earth oxide standard sample

The present invention studies the particle size of rare earth oxides and the particle size range of crystalline sodium chloride, combines the particle size differences between the two, and analyzes that when the particle size range meets the particle size range of mixed rare earth oxides, the uniformity requirements can be met, and the mixed The particle size distribution (Figure 6) and scanning electron microscope image (Figure 7) of rare earth oxides (lanthanum, cerium, praseodymium, and neodymium). Among them, in Figure 6, the particle size D10 of (lanthanum, cerium, praseodymium, and neodymium) rare earth oxides is 1.53μm, particle size D50 is 4.40μm, particle size D90 is 10.8μm. According to the particle size range of mixed rare earth oxides, the grinding time of the standard sample was repeatedly tested to control the grinding effect, and the REO content in the sample was detected. Based on the stability analysis of the REO results, the grinding time was determined to be 3 minutes to obtain the optimal particle size and its particle size distribution curve. , wherein the particle size distribution curve of the rare earth oxide standard sample in Example 1 is shown in Figure 8, and the particle size distribution curve of the rare earth oxide standard sample in Example 4 is shown in Figure 9.

3. Uniformity test results of rare earth oxide standard samples

(1) 15 times of detection of non-matrix elements in the rare earth oxide standard sample in Example 1 Take the results as an example to determine the uniformity of the standard sample. Average represents the average value, Std Dev represents the standard deviation, and RSD represents the relative standard deviation. The results are shown in Table 1.

Table 1 Uniformity detection results of non-matrix elements in the rare earth oxide standard sample in Example 1

It can be seen from the data in Table 1 that the content of K, Ca, Fe, Cu, and Zn trace elements ranges from 0.9 to 30 ppm. The uniformity detection of trace elements can better illustrate the uniformity of the material. The RSDs of K, Ca, Fe, Cu, and Zn are 6.92%, 7.41%, 6.03%, 10.63%, and 27.09% respectively, which meet the measurement fluctuations of trace elements and can prove that the uniformity of the standard sample is good.

(2) Taking the 15 detection results of non-matrix elements in the rare earth oxide standard sample in Example 4 as an example, determine the uniformity of the standard sample. The results are shown in Table 2.

Table 2 Uniformity test results of non-matrix elements in the rare earth oxide standard sample in Example 4

It can be seen from the data in Table 2 that the content of K, Ca, Fe, Cu, and Zn trace elements ranges from 0.9 to 30 ppm. The uniformity detection of trace elements can better illustrate the uniformity of the material. The RSDs of K, Ca, Fe, Cu, and Zn are 11.72%, 8.10%, 10.63%, 10.93%, and 24.94% respectively, which meet the measurement fluctuations of trace elements and can prove that the uniformity of the standard sample is good.

4. Stability test results of rare earth oxide standard samples

Under the condition of eliminating the influence of factors such as sample quality, uniformity, heating rate, atmosphere pressure, etc., analyze the TG curve and DSC curve to determine whether the standard sample candidate corresponds to a change in mass according to a certain thermal effect, and further identify the corresponding mass of the thermal effect. The process of material transformation. Understanding the current actual mass of the standard sample at the reaction temperature facilitates accurate judgment of comprehensive thermal stability. Among them, TG and DSC in comprehensive thermal analysis are tested according to JB/T6856-1993 standard.

Among them, Figure 10 shows the comprehensive thermal analysis curve of mixed rare earth oxides. In the DSC curve, the peak comprehensive analysis: the area is 27.36J/g, the peak is 299.2°C, the peak starting point is 273.4°C, the peak end point is 326.3°C, the peak The width is 41.8°C and the peak height is 0.1264mW/mg; in the TG curve corresponding to the peak of the DSC curve, the mass change of the mixed rare earth oxide is 1.89%. From 326.3°C to the end of the heat treatment, the mass change of the mixed rare earth oxide is 1.05%, the final residual mass is 97.06% (1199℃).

Figure 11 is the thermal analysis curve of the lanthanum cerium rare earth oxide standard sample in Example 1. The peak comprehensive analysis of the DSC curve: the peak area is 37.61J/g, the peak value is 322.1°C, the peak starting point is 289.6°C, and the peak end point is 346.8 ℃. Figure 12 is the thermal analysis curve of the praseodymium and neodymium rare earth oxide standard sample in Example 4. The comprehensive peak analysis of the DSC curve: the peak area is 180.71J/g, the peak value is 809.2°C, the starting point of the peak is 799.1°C, and the end point of the peak is 816.3℃. It can be seen from the TG curves and DSC curves of the lanthanum cerium rare earth oxide standard sample and praseodymium neodymium rare earth oxide standard sample that the oxide standard sample has good thermal stability below 60°C. It can be seen from Figure 11 and Figure 12 that the lanthanum cerium rare earth oxide standard sample and the praseodymium neodymium rare earth oxide standard sample did not undergo obvious mass changes or heat changes in the temperature range of 30°C to 300°C, proving that the samples do not change in this temperature range. Changes in physical and chemical properties will occur, and storage and transportation conditions are required.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions recorded in the foregoing embodiments, or to equivalently replace some or all of the technical features; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention. range.

Claims (10)

1. A rare earth oxide standard sample is characterized in that it includes a homogeneous mixture of rare earth oxides and sodium chloride; in the rare earth oxide standard sample, the rare earth oxide is 28% to 42% in terms of mass percentage;

   The rare earth oxides include lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide;

   The lanthanum oxide is 0.1% to 15%, the cerium oxide is 0.2% to 28%, the praseodymium oxide is 0.1% to 8%, and the neodymium oxide is 0.5% to 32%.
2. The rare earth oxide standard sample according to claim 1, wherein the particle size D10 of the rare earth oxide standard sample is 0.1 to 1 μm;

   The particle size D50 of the rare earth oxide standard sample is 0.5-3 μm;

   The particle size D90 of the rare earth oxide standard sample is 1 to 8 μm.
3. The rare earth oxide standard sample according to claim 1, characterized in that the rare earth oxide is lanthanum cerium oxide or praseodymium neodymium oxide.
4. The rare earth oxide standard sample according to claim 3, characterized in that it contains at least one of the following characteristics (1) to (3):

   (1) In terms of mass percentage, in the rare earth oxide standard sample, the lanthanum cerium oxide is 38% to 42%;

   The mass percentages of each component in the lanthanum cerium oxide of the rare earth oxide standard sample are respectively: lanthanum oxide is 13% to 15%, cerium oxide is 24% to 28%, and praseodymium oxide is 0.1% to 0.4%. Neodymium oxide is 0.5% to 1%;

   (2) In the lanthanum cerium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.75 to 2;

   (3) In the lanthanum cerium oxide, the mass ratio of neodymium oxide and praseodymium oxide is 2.5 to 5.
5. The rare earth oxide standard sample according to claim 3, characterized in that it contains At least one of the following characteristics (1) to (3):

   (1) In terms of mass percentage, in the rare earth oxide standard sample, the praseodymium and neodymium oxide is 28% to 32%;

   The mass percentages of each component in the praseodymium and neodymium oxide of the rare earth oxide standard sample are respectively: 0.1% to 0.3% for lanthanum oxide, 0.2% to 0.5% for cerium oxide, and 6% to 8% for praseodymium oxide. Neodymium oxide is 21% to 24%;

   (2) In the praseodymium and neodymium oxide, the mass ratio of cerium oxide and lanthanum oxide is 1.65 to 2;

   (3) In the praseodymium and neodymium oxide, the mass ratio of neodymium oxide and praseodymium oxide is 2.9 to 3.6.
6. The rare earth oxide standard sample according to claim 1, characterized in that the rare earth oxide standard sample also includes trace elements, and the content of the trace elements is 0.5 to 50 ppm;

   The trace elements include K, Ca, Fe, Cu and Zn.
7. The method for preparing a rare earth oxide standard sample according to any one of claims 1 to 6, characterized in that it includes the following steps:

   Grind the mixture of rare earth oxide raw materials and sodium chloride raw materials, and then mix them;

   The rare earth oxide raw materials include lanthanum oxide raw materials, cerium oxide raw materials, praseodymium oxide raw materials and neodymium oxide raw materials.
8. The method for preparing a rare earth oxide standard sample according to claim 7, characterized in that the method for preparing a mixture of the rare earth oxide raw material and the sodium chloride raw material includes: combining the rare earth oxide raw material and sodium chloride. Raw materials are premixed;

   The premixing time is 2 to 3 hours.
9. The method for preparing a rare earth oxide standard sample according to claim 7, characterized in that it includes at least one of the following features (1) to (3):

   (1) The grinding time is 170 to 200 seconds;

   (2) The mixing time is 170 to 190 minutes;

   (3) The sodium chloride raw material is superior grade pure sodium chloride.
10. The method for preparing a rare earth oxide standard sample according to claim 7, further comprising: performing uniformity testing and stability testing on the rare earth oxide standard sample.