Method for analyzing and testing silicon and yttrium in yttrium silicate

Abstract

The invention discloses a method for analyzing and testing contents of silicon and rare earth in yttrium silicate, and belongs to the technical field of chemical analysis of rare earth materials. The method mainly comprises the following steps: melting a yttrium silicate sample in an alkaline flux, leaching, adjusting the pH value of the solution, converting the yttrium element in the product into yttrium hydroxide precipitate, converting the silicon element into soluble silicate, and filtering. The content of the silicon element is calculated after filtrate treatment, and the content of the yttrium element is calculated after filter residues are treated and weighed. The method solves the problem of lack of quantitative analysis technology of silicon and yttrium elements in the yttrium silicate sample, and the test method is accurate, rapid, scientific and reliable.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical analysis of rare earth materials, and relates to an analytical method for silicon and yttrium in yttrium silicate. Technical Background

[0002] Yttrium silicate (chemical formula Y 2 SiO 5 ) is an extremely important rare earth silicate material, known for its excellent properties in high-temperature environments. These properties include excellent oxidation resistance, corrosion resistance, stability, and creep resistance, as well as unique optical and electronic characteristics, making it widely used in the fields of high-temperature structural materials and scintillation crystals. In addition, the chemical composition of yttrium silicate is the key to determining its crystal structure and phase transformation. The contents of silicon and yttrium have a decisive influence on the corrosion resistance, mechanical properties, thermal expansion coefficient matching, and scintillation properties of the material. Therefore, accurately determining the contents of silicon and yttrium is crucial for the performance parameters, quality control, and product upgrading of yttrium silicate.

[0003] In terms of product standards and technical documents related to yttrium silicate, the group standard T / CSTM 00035-2020 "Cerium-doped Yttrium Silicate Scintillation Crystal" has been issued. This standard stipulates the technical requirements and other information of cerium-doped yttrium silicate scintillation crystals, but does not provide a detection method for chemical composition. In addition, the patent document CN118754663A (Patent Document 1) discloses a yttrium silicate ceramic material, its preparation method and application. According to the description in its specification, this yttrium silicate ceramic material includes 65-80% yttrium oxide, 15-30% silicon dioxide, and 2-8% zirconium oxide by mass percentage, which only shows the specific content ranges of silicon and yttrium in the yttrium silicate material.

[0004] With the continuous in-depth research on yttrium silicate materials, the influence of the contents of the two main components, silicon and yttrium, on the material properties has become increasingly important. Therefore, accurately determining the contents of silicon and yttrium in yttrium silicate materials is of extremely important significance for material research. However, there is no report on the quantitative determination of the contents of silicon and yttrium in yttrium silicate materials in the currently published patents, standards, and literature, which indicates that there is still room for further research and development in this field, and it has important practical significance for promoting the scientific development and industrial application of yttrium silicate materials. Summary of the Invention

[0005] In order to solve the problem of component analysis of silicon and yttrium in yttrium silicate materials, the present invention proposes an analytical method that can effectively separate silicon and yttrium and achieve precise quantitative detection of their contents. This test method is characterized by accuracy, rapidity, and scientific reliability, providing an efficient and reliable solution for the component analysis of yttrium silicate materials.

[0006] The present invention provides the following technical solutions to solve the above technical problems:

[0007] A method for analyzing and testing silicon and yttrium in yttrium silicate, comprising the following steps:

[0008] (1) Spread a small amount of sodium hydroxide at the bottom of a corundum crucible, place a certain amount of yttrium silicate sample in the corundum crucible, mix well and then cover with a certain amount of sodium hydroxide, cover the crucible and place it in a muffle furnace for heating and melting, and conduct a blank test along with the sample;

[0009] (2) Put the corundum crucible, crucible cover and sample after slightly cooling in step (1) into a 300 mL polytetrafluoroethylene beaker, add 150 mL of water, heat until the sample is completely leached, wash out the crucible and crucible cover, adjust the pH of the solution, filter, and retain the filtrate containing soluble silicic acid and the filter residue containing yttrium hydroxide;

[0010] (3) Place the filtrate containing soluble silicic acid obtained in step (2) in a 400 mL beaker, add 10 mL of hydrochloric acid and 40 mL of perchloric acid, heat until perchloric acid fumes are evolved and continue for 30 - 60 min, then filter, and retain the filter residue containing silica gel and the filter paper;

[0011] (4) Put the filter residue and filter paper obtained in step (3) into a platinum crucible, incinerate and then place it in a muffle furnace at 1000 °C for calcination to constant weight, weigh to obtain m 1 , and weigh along with the blank test to obtain m 3 ;

[0012] (5) Add 1 - 2 mL of hydrofluoric acid (ρ = 1.13 g / mL) and 1 - 3 drops of sulfuric acid (ρ = 1.84 g / mL) to the platinum crucible after ashing in step (4), heat until the sulfuric acid fumes are exhausted completely, so that the formed silicon tetrafluoride volatilizes completely, place it in a muffle furnace at 1000 °C for calcination to constant weight, weigh to obtain m 2 , and weigh along with the blank test to obtain m 4 , and then calculate the content of silicon according to the following formula (1),

[0013]

[0014] In formula (1):

[0015] m 1 —The mass of silicon dioxide in the platinum crucible and the sample before volatilization, in grams (g);

[0016] m 2 —The mass of the residue in the platinum crucible and the sample after volatilization, in grams (g);

[0017] m 3 —The mass of silicon dioxide in the platinum crucible and the blank test before volatilization, in grams (g);

[0018] m 4 — Mass of platinum crucible and residue after volatilization in blank test, in grams (g);

[0019] 0.4674 - Conversion factor for converting silicon dioxide to silicon;

[0020] m 0 - Mass of test sample, in grams (g).

[0021] (6) Place the filter residue obtained in step (2) into a 400 mL beaker, add 5 - 10 mL of hydrochloric acid to dissolve the filter residue, add 100 mL of water, and boil; then add oxalic acid solution, adjust the pH to 1.8 - 2.0 with ammonia water to form yttrium oxalate precipitate, heat to boiling and keep warm at 80 - 90 °C for 40 min, cool to room temperature and let stand for 2 - 3 h, filter the solution at this time, and retain the filter paper and filter residue;

[0022] (7) Put the filter paper and filter residue obtained in step (6) into a platinum crucible (weighing m 5 ) that has been weighed to constant weight, place it in a muffle furnace at 900 - 950 °C and burn until constant weight, weigh to get m 6 ,

[0023] Then calculate the content of yttrium according to the following formula (2),

[0024]

[0025] In formula (2):

[0026] m 6 — Mass of yttrium oxide in platinum crucible and test sample, in grams (g);

[0027] m 5 — Mass of platinum crucible, in grams (g);

[0028] 0.7874 - Conversion factor for converting yttrium oxide to metallic yttrium;

[0029] m 0 — Mass of test sample, in grams (g).

[0030] In step (1), the yttrium silicate sample is 0.2 - 0.4 g, the amount of sodium hydroxide added first is 0.2 - 0.5 g, the amount of sodium hydroxide added later is 2 - 4 g, the initial temperature of the muffle furnace is room temperature, the heating-up time is 20 - 60 min, the melting time is 10 - 30 min, and the temperature range after heating-up is 700 - 850 °C; preferably, the heating-up time is 30 - 50 min, preferably, the melting time is 10 - 20 min, and preferably, the temperature range after heating-up is 740 - 800 °C

[0031] In step (2), the pH value of the solution is adjusted to 12 - 14;

[0032] In step (3), the temperature for heating to fume perchloric acid is 200 - 280 °C, and the preferred temperature is 220 - 260 °C;

[0033] In step (4), the ashing operation is as follows: place a graphite ring on a hot plate at 300 - 400 °C (preferably 340 - 380 °C), put the platinum crucible into the ring, cover it with a graphite lid, and leave a gap to supplement air;

[0034] In step (5), the temperature for heating to fume sulfuric acid is 330 - 400 °C, preferably 350 - 380 °C, and the calcination time in a muffle furnace at 1000 °C is 1 - 2 h;

[0035] In step (6), the hydrochloric acid is concentrated hydrochloric acid, the concentration of the oxalic acid solution is 50 g / L, and the ammonia water is (1 + 1) ammonia water solution;

[0036] The water used is deionized water (resistivity 18.25 MΩ·cm).

[0037] The above chemical reaction principle of the present invention mainly involves: after yttrium silicate is melted by an alkaline flux, the silicon element is converted into soluble silicic acid, and the yttrium element is converted into yttrium hydroxide precipitate. The separation of soluble silicic acid and yttrium hydroxide precipitate is achieved by controlling the acidity. Silicic acid dehydrates to form silica gel, and hydrofluoric acid is added to convert the silicon element into silicon tetrafluoride and volatilize it, so that the silicon content is calculated by the mass difference. The yttrium hydroxide precipitate is dissolved with acid, and stable yttrium oxalate precipitate is formed by adding oxalic acid at a certain acidity, and then the mass of the yttrium element is converted.

[0038] The present invention uses the gravimetric method for testing. This testing method is accurate, rapid, scientific and reliable, does not require large-scale instrument equipment, has a low analysis cost, and the testing process is more economical and efficient. It fills the blank in the field of chemical composition analysis of yttrium silicate materials and can be used as a conventional method for analyzing and testing the silicon and yttrium contents in yttrium silicate. This method can also provide reference for the analysis and detection of other rare earth silicate samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of the steps of the test and analysis method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] The analysis and testing method for silicon and yttrium in yttrium silicate of the present invention has the following steps Figure 1 as shown.

[0041] Weigh a certain amount of yttrium silicate. After melting it with an alkaline flux, convert the silicon element into soluble silicate and the yttrium element into yttrium hydroxide precipitate. Separate the soluble silicate and yttrium hydroxide precipitate by controlling the acidity. The silicate is dehydrated to form silica gel, and hydrofluoric acid is added to convert the silicon element into silicon tetrafluoride, which is then volatilized and removed completely. Thus, calculate the silicon content by the mass difference. Dissolve the yttrium hydroxide precipitate with acid, add oxalic acid at a certain acidity to form a stable yttrium oxalate precipitate, and then convert it to the mass of the yttrium element.

[0042] In addition, the reagents used in the said testing method are as follows:

[0043] Sodium hydroxide is a solid powder of guaranteed reagent grade.

[0044] Hydrochloric acid is a solution with a concentration of 1.19 g / mL.

[0045] Perchloric acid is a solution with a concentration of 1.67 g / mL.

[0046] Hydrofluoric acid is a solution with a concentration of 1.15 g / mL.

[0047] Sulfuric acid is a solution with a concentration of 1.84 g / mL.

[0048] Oxalic acid is an aqueous solution with a concentration of 50 g / L.

[0049] Ammonia water (1+1) is a solution obtained by diluting concentrated ammonia water with a concentration of 0.90 g / mL and water in a volume ratio of 1:1.

[0050] Water is deionized water with a resistivity of 18.25 MΩ·cm or more.

[0051] Example 1:

[0052] In this example, yttrium silicate powder is used as the sample for the determination of silicon and yttrium. The specific steps are as follows:

[0053] (1) Cover 0.3 g of sodium hydroxide at the bottom of a corundum crucible. Weigh 0.2 g of yttrium silicate sample (Sample 1#, denoted as m 0 ) and place it in the crucible. After mixing, add another 3 g of sodium hydroxide. Cover the crucible and place it in a muffle furnace. Heat it from the initial temperature to 750 °C in 30 minutes and keep it at 750 °C for 15 min. Conduct a blank test along with the sample.

[0054] (2) Place the slightly cooled corundum crucible, crucible cover and sample from step (1) together in a 300 mL polytetrafluoroethylene beaker. Add 150 mL of water and heat it until the sample is completely leached out, then wash out the crucible and crucible cover. Subsequently, add sodium hydroxide solution and adjust the pH value of the solution between 12 and 14. Filter the solution through a slow quantitative filter paper into a 400 mL beaker and wash the beaker and filter paper 8 - 10 times with water. Keep the filtrate for the analysis of silicon element and keep the residue for the analysis of yttrium element.

[0055] (3) Add 10 mL of concentrated hydrochloric acid and 40 mL of perchloric acid to the filtrate obtained in step (2), heat and evaporate until a large amount of perchloric acid fumes emerge and continue for 30 - 40 min until the reaction is complete, then remove and cool. Add water to the beaker to about 100 mL, heat to boiling and then cool. Filter, wash the beaker and filter paper with deionized water 5 - 6 times, and then wash the precipitate thoroughly with boiling water until the filtrate is neutral. Place the filter paper together with the precipitate in a pre-weighed platinum crucible, place the platinum crucible in a graphite circle at 360 °C for ashing, cover with a graphite lid, leaving a gap to supplement air.

[0056] (4) After complete ashing, place the platinum crucible in a muffle furnace and calcine at 1000 °C until constant weight, take it out and place it in a desiccator, cool to room temperature, and weigh it as m 1 , and weigh it as m 3 .

[0057] (5) Add 1 - 2 mL of hydrofluoric acid and 1 - 3 drops of sulfuric acid to the platinum crucible, place it on a hot plate until the sulfuric acid fumes are exhausted. Calcine in a high-temperature furnace at 1000 °C until constant weight, take it out and place it in a desiccator, cool to room temperature, and weigh it as m 2 , and weigh it as m 4 .

[0058] (6) Calculation of silicon analysis results:

[0059]

[0060] Where:

[0061] m 1 —The mass of silicon dioxide in the platinum crucible and the sample before volatilization, in grams (g);

[0062] m 2 —The mass of the residue in the platinum crucible and the sample after volatilization, in grams (g);

[0063] m 3 —The mass of silicon dioxide in the platinum crucible and the blank test before volatilization, in grams (g);

[0064] m 4 —The mass of the residue in the platinum crucible and the blank test after volatilization, in grams (g);

[0065] 0.4674 - Conversion factor for converting silicon dioxide to silicon;

[0066] m 0 - The mass of the test sample, in grams (g).

[0067] (6) Place the filter residue obtained in step (2) in a 400 mL beaker, add 10 mL of hydrochloric acid to dissolve the filter residue. Add 100 mL of water and boil. Add 50 mL of oxalic acid solution near boiling point, and adjust the pH to 1.8 - 2.0 with ammonia water solution. Heat to boiling and keep warm at 80 - 90 °C for 40 min, cool to room temperature, and let stand for 2 hours. Then filter with a slow quantitative filter paper, wash the beaker with oxalic acid washing solution 2 - 3 times, and wash the precipitate 8 - 10 times. Keep the precipitate and the filter paper;

[0068] (7) Put the precipitate obtained in step (6) together with the filter paper into a crucible m 5 which has been calcined to constant weight at 950 °C. Heat at low temperature to ash the precipitate and the filter paper. Place the crucible in a muffle furnace at 950 °C and calcine for 1 hour. Take it out and place it in a desiccator, cool to room temperature, and calcine repeatedly until constant weight, denoted as m 6 .

[0069] Calculation of yttrium analysis result:

[0070]

[0071] In the formula:

[0072] m 6 — The mass of yttrium oxide in the platinum crucible and the sample, in grams (g);

[0073] m 5 — The mass of the platinum crucible, in grams (g);

[0074] 0.7874 — Conversion coefficient for converting yttrium oxide to metallic yttrium;

[0075] m 0 — The mass of the test sample, in grams (g).

[0076] Example 2:

[0077] In this example, yttrium silicate powder is used as the test sample for the determination of silicon and yttrium, which specifically includes the following steps:

[0078] (1) Cover the bottom of a corundum crucible with 0.5 g of sodium hydroxide, weigh 0.2 g of yttrium silicate sample (No. 2#, denoted as m 0 ) and place it in the crucible. After mixing, add another 5 g of sodium hydroxide, cover it, and place it in a muffle furnace. Heat from the initial temperature to 800 °C in 30 min and keep at 800 °C for 20 min. Conduct a blank test along with the sample.

[0079] (2) Other operation steps and calculation methods are the same as those in Example 1, which are omitted here.

[0080] Method precision test:

[0081] According to the above experimental steps, the method precision test was carried out on the yttrium silicate samples of the above two embodiments, as follows:

[0082] Table 1 Results of precision test of yttrium silicate

[0083]

[0084]

[0085] From the data in the above table, it can be seen that the standard deviation (SD) of the present invention is less than 0.055%, and the relative standard deviation (RSD) is less than 0.18%. Therefore, it is considered that the precision of the analysis and test method for analyzing the contents of silicon and yttrium in yttrium silicate is good. Moreover, from the operation steps, the analysis cost is low, and the test process is economical and efficient. Therefore, it provides an efficient and reliable solution for the component analysis of yttrium silicate materials. Thus, it is considered that this test method is suitable for popularization and application in the field of rare earth chemical analysis.

Claims

1. An analytical test method for silicon and yttrium in yttrium silicate is carried out according to the following steps: (1) A small amount of sodium hydroxide is placed on the bottom of a corundum crucible, a certain amount of yttrium silicate sample is placed in the corundum crucible, mixed and then covered with a certain amount of sodium hydroxide, covered and placed in a muffle furnace to heat and melt, and a blank sample is prepared along with the sample; wherein, The yttrium silicate sample is 0.2-0.4g, the amount of sodium hydroxide added first is 0.2-0.5g, and the amount of sodium hydroxide added is 2-4g. The initial temperature of the muffle furnace is room temperature, the heating time is 20-60min, and the melting time is 10-30min; the temperature range after heating is 700-850℃; (2) placing the slightly cooled corundum crucible, crucible cover and sample in step (1) into a 300 mL polytetrafluoroethylene beaker, adding 150 mL of water, heating until the sample is completely leached, washing out the crucible, adjusting the pH of the solution, filtering, and retaining the filtrate containing soluble silicic acid and the filter residue containing yttrium hydroxide; (3) placing the filtrate containing soluble silicic acid obtained in step (2) in a 400 mL beaker, adding 10 mL of hydrochloric acid and 40 mL of perchloric acid, heating until perchloric acid smoke is emitted, and continuing for 30-60 minutes to dehydrate the silicic acid to form silica gel, and then filtering, retaining the filter residue and filter paper; (4) placing the filter residue and filter paper in step (3) into a platinum crucible, ash them, and burn them in a muffle furnace at 1000° C. to constant weight, weighing them to obtain m1, and weighing them together with a blank test to obtain m3; (5) Add 1-2 mL of hydrofluoric acid and 1-3 drops of sulfuric acid to the platinum crucible after constant weight in step (4), heat until the sulfuric acid smoke disappears, so that the formed silicon tetrafluoride is completely volatilized, and then place it in a muffle furnace at 1000° C. and burn it to constant weight, weigh it to obtain m2, and weigh it together with the blank test to obtain m4, so as to calculate the silicon content according to the following formula (1): In formula (1): m1—the mass of silicon dioxide in the platinum crucible and the sample before volatilization, in grams; m2—the mass of the residue in the platinum crucible and the sample after volatilization, in grams; m3—the mass of platinum crucible and silicon dioxide before volatilization in the blank test, in grams; m4—the mass of the platinum crucible and residue after volatilization in the blank test, in grams; 0.4674 - Conversion factor of silicon dioxide to silicon; m0-mass of the sample, in grams; (6) placing the filter residue containing yttrium hydroxide in step (2) in a 400 mL beaker, adding 5-10 mL of hydrochloric acid to dissolve the filter residue, adding 100 mL of water, boiling, adding oxalic acid solution, and then adding ammonia water to adjust the pH to 1.8-2.0 to form yttrium oxalate precipitate, heating to boil and keeping at 80-90° C. for 40 min, cooling to room temperature and leaving for 2-3 h, filtering the solution at this time, retaining the filter paper and the filter residue; (7) placing the filter paper and filter residue from step (6) into a platinum crucible with a constant weight of m5, placing it in a muffle furnace at 900-950° C. and burning it to a constant weight, weighing it to obtain m6, and then calculating the mass of the yttrium element based on the following formula (2); In formula (2): m6—the mass of yttrium oxide in the platinum crucible and the sample, in grams; m5—the mass of the platinum crucible, in grams; 0.7874—Conversion factor of yttrium oxide to metallic yttrium; m0—mass of the sample, in grams.

2. The method for analyzing and testing silicon and yttrium in yttrium silicate according to claim 1, characterized in that: In step (2), the pH value of the solution is adjusted to 12-14.

3. The analytical test method for silicon and yttrium in yttrium silicate according to claim 1, characterized in that: In step (3), the heating temperature to generate perchloric acid fumes is 200-280°C.

4. The method for analyzing and testing silicon and yttrium in yttrium silicate according to claim 1, characterized in that: In step (4), the ashing operation is to place a graphite ring on a hot plate at 300-400° C., place a platinum crucible in the ring, cover it with a graphite cover, and leave a gap to replenish air.

5. The method for analyzing and testing silicon and yttrium in yttrium silicate according to claim 1, characterized in that: In step (4), the mixture is placed in a muffle furnace at 1000° C. and calcined for 1-2 h.

6. The method for analyzing and testing silicon and yttrium in yttrium silicate according to claim 1, characterized in that: In step (5), the heating temperature to generate sulfuric acid fumes is 330-400°C.

7. The method for analyzing and testing silicon and yttrium in yttrium silicate according to claim 1, characterized in that: In step (6), the hydrochloric acid is concentrated hydrochloric acid, the concentration of the oxalic acid solution is 50 g / L, and the ammonia water is an ammonia water (1+1) solution.

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