Chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ore

Abstract

The invention relates to the technical field of chemical analysis, in particular to a chemical analysis method for rapidly measuring niobium and tantalum elements in high-tin ore, which comprises the following steps: preparing a to-be-measured sample melt: weighing a high-tin ore sample, and putting the high-tin ore sample into a corundum crucible containing sodium peroxide for pretreatment to obtain the melt; preparing a to-be-detected sample liquid; adding concentrated hydrofluoric acid and concentrated hydrochloric acid into the melt for acidification; the hydrofluoric acid with high complexing property is selected to replace tartaric acid to serve as a stable complexing agent of niobium and tantalum, the hydrochloric acid acidizes the alkali melt, the nitric acid serves as an oxidizing agent, and a large amount of tin element is removed according to the fact that the hydrochloric acid reacts with tin ions to generate metastannic acid precipitate. The niobium and the tantalum in the high-content tin ore are separated from a large number of tin matrixes, the test accuracy is guaranteed, the influence of the high-content tin matrix effect is avoided, the niobium and the tantalum in the high-content tin ore can be rapidly and efficiently measured, and the method has the advantages of being good in separation effect, high in recovery rate, good in precision and the like.

Description

Technical Field

[0001] The invention relates to the technical field of chemical analysis, and in particular to a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores. Background Art

[0002] Niobium and tantalum are rare metal elements. In nature, niobium and tantalum are mainly niobate and tantalate minerals. They have the same properties and similar atomic and ionic radii, so the two elements almost always coexist in natural minerals. Niobium and tantalum alloys can be used as high-temperature resistant structural materials for spacecraft, structural materials for atomic reactors, and used in acid-resistant equipment, heat exchangers and heaters in the petroleum and chemical industries.

[0003] According to the literature, niobium and tantalum are very stable elements and are stable to many acids at room temperature, but niobium tantalum and its compounds are easily soluble in a mixed acid of hydrofluoric acid and nitric acid. Sulfuric acid fuming is very effective in completely dissolving its samples. There are many analytical methods for niobium and tantalum in ores, mineral processing materials, and metallurgical materials. There are few chemical separation, enrichment, and analytical testing methods for niobium and tantalum in high-tin ores. At present, the main analytical testing methods for niobium and tantalum are atomic absorption spectrophotometry, ICP-AES, gravimetric method, colorimetry, and titration. The main separation and enrichment methods for niobium and tantalum are precipitation, extraction, and ion exchange.

[0004] The main component of high-tin ore is cassiterite SnO ２ , in addition, it contains impurity elements such as iron, manganese, tungsten, molybdenum, niobium, tantalum, silicon, arsenic, zirconium, beryllium, bismuth, antimony, etc., which are insoluble in hydrochloric acid, nitric acid and aqua regia. The most effective method to decompose tin ore is alkali fusion method, and ICP-AES method is used for determination after acidification and constant volume. The traditional alkali fusion method can make the sample fully and completely melted, but the alkali fusion method has a disadvantage, that is, the introduction of a large amount of sodium matrix, as well as the matrix effect of the high content of tin in the ore itself, the dilution multiple and the interference of coexisting ions and other uncertainties, the instrument measurement error will be relatively large; in addition, tartaric acid is commonly used in the laboratory as a chelating agent for niobium and tantalum, but its disadvantage is that it is not very stable when adding hydrochloric acid to acidify the alkali melt, and the niobium and tantalum compounds will still be partially hydrolyzed, resulting in the determination of niobium and tantalum in high-tin ores. Problems such as slow determination speed, poor separation effect, low recovery rate and poor precision. Summary of the invention

[0005] The present invention provides a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ore, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problem of poor separation effect caused by the instability of tartaric acid used as a chelating agent for niobium and tantalum in the prior art for decomposing tin ore.

[0006] To solve the above problems, the present invention provides a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores, comprising the following steps: The first step is to prepare a melt of the sample to be tested: weigh a high-tin ore sample and put it into a corundum crucible containing sodium peroxide for pretreatment to obtain a melt; The second step is to prepare the sample liquid to be tested: add concentrated hydrofluoric acid and concentrated hydrochloric acid to the melt for acidification to form a clear sample liquid to be tested without small bubbles; The third step is ICP-AES detection: concentrated nitric acid is added to the sample liquid to precipitate tin with metastannic acid, the filtrate is filtered and fixed to volume, the working parameters of the ICP-AES spectrometer are set, and the niobium and tantalum content in the filtrate is determined by ICP-AES; Step 4: Re-weigh the high-tin ore sample and perform spike recovery and precision tests according to the first, second and third steps.

[0007] The above also includes performing blank tests throughout the entire test process.

[0008] The first step includes weighing 0.2000~0.5000g of high-tin ore sample and placing it in a 30mm corundum crucible pre-paved with 1g of sodium peroxide, then adding 1~3g of sodium peroxide, placing it in a muffle furnace, melting it at a temperature of 650°C for 10 minutes, taking out the corundum crucible and shaking it well, and then continuing to place it in the muffle furnace to heat and melt it, melting it at a temperature of 650°C for 10 minutes, taking it out, and cooling it to room temperature.

[0009] The second step includes placing the corundum crucible together with the melt in a 300ml polytetrafluoroethylene beaker, adding 80ml of deionized water, immersing the melt on a hot plate at a temperature of 50-60°C, washing the corundum crucible alternately with deionized water and dilute hydrochloric acid with a volume ratio of 1:3, and then taking it out, adding 5-10ml of concentrated hydrofluoric acid and 10-20ml of concentrated hydrochloric acid to the beaker for low-temperature boiling and acidification, dissolving the liquid until it is clear and no small bubbles are generated, and then taking it out and cooling it to room temperature.

[0010] The third step includes adding 10 ml of concentrated nitric acid to the sample liquid to be tested in the second step, stirring it fully with a plastic rod to completely precipitate the tin as metastannic acid, adjusting the volume to a 250 ml polytetrafluoroethylene volumetric flask, shaking it well, filtering it, and determining the niobium and tantalum content of the filtrate by ICP-AES.

[0011] In the third step above, the operating parameters of the ICP-AES spectrometer are: plasma observation mode: horizontal; pump speed: 50 rpm; auxiliary gas flow rate: 0.5 L / min; nebulizer flow rate: 0.45 L / min; cooling gas flow rate: 12.0 L / min; measurement spectral lines: Nb319.4 nm, Ta301.2 nm.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The present invention solves the instability of the tartaric acid solution of niobium and tantalum by selecting hydrofluoric acid with strong complexing property instead of tartaric acid, acidifying the alkali melt with hydrochloric acid, and removing a large amount of tin element by niobium and tantalum as an oxidant to generate metastannic acid precipitation according to its reaction with tin ions. On the premise of ensuring that niobium and tantalum are not lost, they are separated from a large amount of tin matrix to ensure the accuracy of the test and avoid the influence of the high-content tin matrix effect. Through experimental comparison, the sodium matrix has little effect on the determination of niobium and tantalum. Through the recovery test and the precision test, the results are good. Therefore, the present invention can quickly and efficiently determine niobium and tantalum in high-content tin ore, and has the advantages of good separation effect, high recovery rate and good precision.

[0013] 2. The present invention adopts sodium peroxide to alkali-melt the high-tin ore sample, hydrochloric acid to acidify it, hydrofluoric acid to carry out complex reaction on niobium and tantalum, and uses nitric acid to make tin ions form metastannic acid precipitation to achieve the separation effect. Through the comparison of the sodium matrix experiment in the solution, it is found that the method of the present invention has little effect on the determination of the niobium and tantalum content. Therefore, the present invention avoids the problem that the instrument measurement error will be relatively large due to the introduction of a large amount of sodium matrix in traditional alkali fusion, the matrix effect of the high tin content of the ore itself, the dilution multiple and the interference of the uncertainty of coexisting ions, etc., and eliminates the matrix effect of the high tin content in the measurement process, thereby ensuring the accuracy and reliability of the test results. DETAILED DESCRIPTION

[0014] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0015] Example 1: The present invention discloses a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores, comprising the following steps: The first step is to prepare a melt of the sample to be tested: weigh a high-tin ore sample and put it into a corundum crucible containing sodium peroxide for pretreatment to obtain a melt; The second step is to prepare the sample liquid to be tested: add concentrated hydrofluoric acid and concentrated hydrochloric acid to the melt for acidification to form a clear sample liquid to be tested without small bubbles; The third step is ICP-AES detection: concentrated nitric acid is added to the sample liquid to precipitate tin with metastannic acid, the filtrate is filtered and fixed to volume, the working parameters of the ICP-AES spectrometer are set, and the niobium and tantalum content in the filtrate is determined by ICP-AES; In the fourth step, re-weigh the high-tin ore sample and perform spike recovery and precision tests according to the first, second and third steps.

[0016] This also includes a blank test during the entire test process. A blank test is a test that is performed without adding a sample, according to the sample analysis conditions and operating steps; the purpose is to eliminate system errors caused by reagent impurity or reagent interference.

[0017] Among them, the first step includes weighing 0.2000~0.5000g of high-tin ore sample and placing it in a 30mm corundum crucible pre-paved with 1g of sodium peroxide, then adding 1~3g of sodium peroxide, putting it into a muffle furnace, melting it at a temperature of 650°C for 10 minutes, taking out the corundum crucible and shaking it well, and then continuing to put it in the muffle furnace to heat and melt it, melting it at a temperature of 650°C for 10 minutes, taking it out, and cooling it to room temperature.

[0018] The second step includes placing the corundum crucible together with the melt in a 300ml polytetrafluoroethylene beaker, adding 80ml deionized water, immersing the melt in water at 50-60°C on a hot plate, washing the corundum crucible alternately with deionized water and dilute hydrochloric acid with a volume ratio of 1:3 (v / v) and taking it out, adding 5-10ml concentrated hydrofluoric acid (AR) and 10-20ml concentrated hydrochloric acid (AR) into the beaker for low-temperature boiling and acidification, dissolving the liquid until it is clear without the generation of small bubbles, and then taking it out and cooling it to room temperature.

[0019] The third step includes adding 10 ml of concentrated nitric acid (AR) to the sample liquid to be tested in the second step, stirring it with a plastic rod to completely precipitate the tin as metastannic acid, and then adding the volume to a 250 ml polytetrafluoroethylene volumetric flask, shaking it well, filtering it, and determining the niobium and tantalum content of the filtrate by ICP-AES. The volume is determined according to the experimental needs.

[0020] Among them, in the third step, the working parameters of the ICP-AES spectrometer are: plasma observation mode: horizontal; pump speed: 50rmp; auxiliary gas flow: 0.5L / min; nebulizer flow: 0.45L / min; cooling gas flow: 12.0L / min; measurement spectral lines: Nb319.4nm, Ta301.2nm.

[0021] Among them, the chemical reagents used in the test method adopted by the present invention are all analytically pure.

[0022] According to the chemical properties of niobium and tantalum, the sodium salt of niobium and tantalum acid after alkali melting produces a precipitate in the aqueous solution, which is collectively called earth acid. Tartaric acid commonly used in laboratories can be used as a chelating agent for niobium and tantalum, but its disadvantage is that it is not very stable when hydrochloric acid is added to acidify the alkali melt, and the niobium and tantalum compounds will still be partially hydrolyzed. The present invention adopts alkali melting samples, which can better melt the insoluble elements quickly and completely, avoiding the unsatisfactory acid dissolution and the influence of low results.

[0023] In summary, the embodiment of the present invention solves the instability of the tartaric acid solution of niobium tantalum by selecting hydrofluoric acid with strong complexing property instead of tartaric acid as the stable complexing agent of niobium tantalum, and acidifying the alkali melt with hydrochloric acid. Nitric acid is used as an oxidant to react with tin ions to generate metastannic acid precipitate, thereby removing a large amount of tin element. Under the premise of ensuring that niobium tantalum is not lost, it is separated from a large amount of tin matrix to ensure the accuracy of the test and avoid the influence of the high-content tin matrix effect. Through experimental comparison, the sodium matrix has little effect on the determination of niobium tantalum, and the results of the recovery test and the precision test are good. Therefore, the present invention can quickly and efficiently determine niobium tantalum in high-content tin ore, and has the advantages of good separation effect, high recovery rate and good precision.

[0024] In addition, the present invention adopts sodium peroxide to alkali-melt the high-tin ore sample, hydrochloric acid to acidify, hydrofluoric acid to carry out complex reaction on niobium and tantalum, and uses nitric acid to make tin ions form metastannic acid precipitation to achieve the separation effect. Through the comparison of sodium matrix experiments in the solution, it is found that the method of the present invention has little effect on the determination of niobium and tantalum content. Therefore, the present invention avoids the problem that the instrument measurement error will be relatively large due to the introduction of a large amount of sodium matrix in traditional alkali melting, the matrix effect of the high tin content of the ore itself, the dilution multiple and the interference of the uncertainty of coexisting ions, etc., and eliminates the matrix effect of the high tin content in the measurement process, thereby ensuring the accuracy and reliability of the test results.

[0025] Example 2: The present invention discloses a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores, comprising the following steps: (1) Accurately weigh 0.2000g of a certain high-tin ore sample 1# and put it into a 30mm corundum crucible pre-paved with 1g of sodium peroxide. Then add 1g of sodium peroxide and put it into a muffle furnace. Start melting at low temperature. Melt for 10 minutes at 650℃. Take out the corundum crucible and shake it evenly. Continue to put it into the muffle furnace to heat and melt. Melt for 10 minutes at 650℃. Take it out and cool it to room temperature.

[0026] (2) Place the corundum crucible (1) together with the melt in a 300 ml polytetrafluoroethylene beaker, add 80 ml of deionized water, immerse the melt in water at low temperature (50-60°C) on a hot plate, wash the wall of the corundum crucible with dilute hydrochloric acid (1:3) and deionized water alternately and discard it, add 5 ml of concentrated hydrofluoric acid (AR) and 10 ml of concentrated hydrochloric acid (AR) to the beaker and boil at low temperature to acidify, dissolve the liquid until it is clear and no small bubbles are generated, remove and cool to room temperature.

[0027] (3) Add 10 ml of concentrated nitric acid (AR) to the liquid in (2), stir thoroughly with a plastic rod to completely precipitate the tin as metastannic acid, dilute to a 250 ml polytetrafluoroethylene volumetric flask, shake well, dry filter, and determine the niobium and tantalum content of the filtrate by ICP-AES.

[0028] (4) Accurately weigh another high-tin ore sample 1# from a certain beneficiation process, and perform spike recovery and precision tests according to steps (1), (2), and (3). The analytical results, spike recovery rate, and precision are shown in Table 1.

[0029] Example 3: The present invention discloses a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores, comprising the following steps: (1) Accurately weigh 0.3000g of a certain high-tin ore sample 2# and put it into a 30mm corundum crucible pre-paved with 1g of sodium peroxide, then add 1.5g of sodium peroxide, put it into a muffle furnace, start melting at low temperature, melt for 10 minutes at 650℃, take out the corundum crucible and shake it well, continue to put it into the muffle furnace to heat and melt, melt for 10 minutes at 650℃, take it out and cool it to room temperature.

[0030] (2) Place the corundum crucible (1) together with the melt in a 300 ml polytetrafluoroethylene beaker, add 80 ml of deionized water, immerse the melt in water at low temperature (50-60°C) on a hot plate, wash the wall of the corundum crucible with dilute hydrochloric acid (1:3) and deionized water alternately and discard it, add 8 ml of concentrated hydrofluoric acid (AR) and 15 ml of concentrated hydrochloric acid (AR) to the beaker and boil at low temperature to acidify, dissolve the liquid until it is clear and no small bubbles are generated, remove and cool to room temperature.

[0031] (3) Add 10 ml of concentrated nitric acid (AR) to the liquid in (2), stir thoroughly with a plastic rod to completely precipitate the tin as metastannic acid, dilute to a 250 ml polytetrafluoroethylene volumetric flask, shake well, dry filter, and determine the niobium and tantalum content of the filtrate by ICP-AES.

[0032] (4) Accurately weigh another high-tin ore sample 2# from a certain beneficiation process, and perform spike recovery and precision tests according to steps (1), (2), and (3). The analysis results, spike recovery rate, and precision are shown in Table 2.

[0033] Example 4: The present invention discloses a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores, comprising the following steps: (1) Accurately weigh 0.4000g of a certain high-tin ore sample 3# and put it into a 30mm corundum crucible pre-paved with 1g of sodium peroxide. Then add 3g of sodium peroxide and put it into a muffle furnace. Start melting at low temperature. Melt for 10 minutes at 650℃. Take out the corundum crucible and shake it evenly. Continue to put it into the muffle furnace to heat and melt. Melt for 10 minutes at 650℃. Take it out and cool it to room temperature.

[0034] (2) Place the corundum crucible (1) together with the melt in a 300 ml polytetrafluoroethylene beaker, add 80 ml of deionized water, immerse the melt in water at low temperature (50-60°C) on a hot plate, wash the wall of the corundum crucible with dilute hydrochloric acid (1:3) and deionized water alternately and discard it, add 10 ml of concentrated hydrofluoric acid (AR) and 20 ml of concentrated hydrochloric acid (AR) to the beaker and boil at low temperature to acidify, dissolve the liquid until it is clear and no small bubbles are generated, remove and cool to room temperature.

[0035] (3) Add 10 ml of concentrated nitric acid (AR) to the liquid in (2), stir thoroughly with a plastic rod to completely precipitate the tin as metastannic acid, dilute to a 250 ml polytetrafluoroethylene volumetric flask, shake well, dry filter, and determine the niobium and tantalum content of the filtrate by ICP-AES.

[0036] (4) Accurately weigh another high-tin ore sample 3# from a certain beneficiation process, and perform spike recovery and precision tests according to steps (1), (2), and (3). The analytical results, spike recovery rate, and precision are shown in Table 3.

[0037] Example 5: The present invention discloses a chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores, comprising the following steps: (1) Accurately weigh 0.5000g of a certain high-tin ore sample 4# and put it into a 30mm corundum crucible pre-paved with 1g of sodium peroxide, then add 3g of sodium peroxide, put it into a muffle furnace, start melting at low temperature, melt for 10 minutes at 650℃, take out the corundum crucible and shake it well, continue to put it into the muffle furnace to heat and melt, melt for 10 minutes at 650℃, take it out and cool it to room temperature.

[0038] (2) Place the corundum crucible (1) together with the melt in a 300 ml polytetrafluoroethylene beaker, add 80 ml of deionized water, immerse the melt in water at low temperature (50-60°C) on a hot plate, wash the wall of the corundum crucible with dilute hydrochloric acid (1:3) and deionized water alternately and discard it, add 10 ml of concentrated hydrofluoric acid (AR) and 20 ml of concentrated hydrochloric acid (AR) to the beaker and boil at low temperature to acidify, dissolve the liquid until it is clear and no small bubbles are generated, remove and cool to room temperature.

[0039] (3) Add 10 ml of concentrated nitric acid (AR) to the liquid in (2), stir thoroughly with a plastic rod to completely precipitate the tin as metastannic acid, dilute to a 250 ml polytetrafluoroethylene volumetric flask, shake well, dry filter, and determine the niobium and tantalum content of the filtrate by ICP-AES.

[0040] (4) Accurately weigh another high-tin ore sample 4# from a certain beneficiation process, and perform spike recovery and precision tests according to steps (1), (2), and (3). The analysis results, spike recovery rate, and precision are shown in Table 4.

Claims

1. A chemical analysis method for rapid determination of niobium and tantalum elements in high-tin ores, characterized in that: The following steps are involved: The first step is to prepare a melt of the sample to be tested: weigh a high-tin ore sample and put it into a corundum crucible containing sodium peroxide for pretreatment to obtain a melt; The second step is to prepare the sample liquid to be tested: add concentrated hydrofluoric acid and concentrated hydrochloric acid to the melt for acidification to form a clear sample liquid to be tested without small bubbles; The third step is ICP-AES detection: concentrated nitric acid is added to the sample liquid to precipitate tin with metastannic acid, the filtrate is filtered and fixed to volume, the working parameters of the ICP-AES spectrometer are set, and the niobium and tantalum content in the filtrate is determined by ICP-AES; Step 4: Re-weigh the high-tin ore sample and perform spike recovery and precision tests according to the first, second and third steps.

2. A chemical analysis method for rapid determination of niobium and tantalum elements in high-tin ores according to claim 1, characterized in that: It also includes performing blank tests throughout the entire test process.

3. The chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores according to claim 1, characterized in that: The first step includes weighing 0.2000-0.5000g of high-tin ore sample and placing it in a 30mm corundum crucible pre-paved with 1g of sodium peroxide, then adding 1-3g of sodium peroxide, placing it in a muffle furnace, melting it to a temperature of 650°C for 10min, taking out the corundum crucible and shaking it well, and then continuing to place it in the muffle furnace to heat and melt it, melting it for 10min when the temperature is raised to 650°C, taking it out, and cooling it to room temperature.

4. A chemical analysis method for rapid determination of niobium and tantalum elements in high-tin ores according to claim 1, characterized in that: The second step includes placing the corundum crucible together with the melt in a 300ml polytetrafluoroethylene beaker, adding 80ml of deionized water, immersing the melt in water at a temperature of 50-60°C on a hot plate, washing the corundum crucible alternately with deionized water and dilute hydrochloric acid with a volume ratio of 1:3, and then taking it out, adding 5-10ml of concentrated hydrofluoric acid and 10-20ml of concentrated hydrochloric acid to the beaker for low-temperature boiling and acidification, dissolving the liquid until it is clear without the generation of small bubbles, and then taking it out and cooling it to room temperature.

5. The chemical analysis method for rapidly determining niobium and tantalum elements in high-tin ores according to claim 1, characterized in that: The third step includes adding 10 ml of concentrated nitric acid to the sample liquid to be tested in the second step, stirring it fully with a plastic rod to completely precipitate the tin as metastannic acid, adjusting the volume to a 250 ml polytetrafluoroethylene volumetric flask, shaking it well, filtering it, and determining the niobium and tantalum content of the filtrate by ICP-AES.

6. A chemical analysis method for rapid determination of niobium and tantalum elements in high-tin ores according to claim 1, characterized in that: In the third step, the operating parameters of the ICP-AES spectrometer are: plasma observation mode: horizontal; pump speed: 50 rpm; auxiliary gas flow: 0.5 L / min; nebulizer flow: 0.45 L / min; cooling gas flow: 12.0 L / min; and measured spectral lines: Nb319.4 nm, Ta301.2 nm.

Images