CN114894879A - For accelerator mass spectrometer measurements 10 Be and 26 preparation method of Al sample - Google Patents

Abstract

The present disclosure provides a preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer, comprising: sequentially pulverizing, sieving, adsorbing magnetic minerals and sorting by a magnetic separator on rocks containing quartz to obtain sample particles, Remove the carbonate in the sample particles, use mixed acid to dissolve the sample particles and then perform ultrasonic treatment to obtain a quartz sample; add Be carrier and Al carrier to the quartz sample, and use high-grade pure HF on a heating plate to completely dissolve the quartz sample to obtain sample solution, and evaporate the sample solution to dryness; remove Fe, Ti, Ca and Mg; activate the ion exchange column, use ion exchange resin to separate and purify Be and Al; prepare Be oxide and Al oxide. The present disclosure can effectively remove magnetic substances, aluminosilicate minerals such as feldspar, and atmospheric origin ¹⁰ Be, can well separate Be and Al, and can also effectively improve the recovery rate of Be.

Description

Preparation method for measuring 10Be and 26Al samples by accelerator mass spectrometer

technical field

The present disclosure relates to a preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer.

Background technique

The cosmogenic nuclide dating method is the most eye-catching technical method in the development of geochronology. With the birth of accelerator mass spectrometry (AMS), ¹⁰ Be/ ⁹ Be and ²⁶ Al/ ¹⁰ Be dating techniques have been widely used in exposure age and The study of sedimentary chronology.

Quartz has become one of the cosmogenic nuclide dating methods because of its characteristics of simultaneous production of Be and Al dinuclide target nucleus and dense crystal structure, which is not easy to be polluted by atmospheric ¹⁰ Be and low ²⁷ Al content. Ideal for dating substances.

Before dissolving and separating the quartz to separate ¹⁰ Be and ²⁶ Al, the sample needs to be separated and purified to obtain pure quartz particles, and then the Be and Al in the quartz particles are extracted. The classic method established by Kohl and Nishiizumi. However, these methods still have problems such as residual impurities such as magnetic minerals, influence of atmospheric origin ¹⁰ Be, and low Be recovery rate, which lead to inaccurate dating results.

SUMMARY OF THE INVENTION

In order to solve at least one of the above technical problems, the present disclosure provides a preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer.

The preparation method of the present disclosure for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer includes:

The rock containing quartz is pulverized, sieved, adsorbed magnetic minerals and sorted by a magnetic separator in sequence to obtain sample particles with a particle size of 0.1 to 0.6 mm;

Use 6mol/L HCl to remove carbonate in the sample particles;

Etch the sample particles with a mixed acid 12.5 times the weight of impurities in the sample particles, and obtain a quartz sample with an Al content of less than 200 ppm after ultrasonic treatment;

Add Be carrier and Al carrier to the quartz sample, use high-grade pure HF on a hot plate to completely dissolve the quartz sample to obtain a sample solution, and evaporate the sample solution to dryness;

Use NaOH solution to remove Fe, Ti, Ca and Mg;

Activate the ion exchange column, and use ion exchange resin to separate and purify Be and Al;

Preparation of Be oxides and Al oxides using solutions obtained by separating and purifying Be and Al;

Wherein, using ion exchange resin to separate and purify Be and Al includes: firstly using 1.1 mol/L HCl to separate and purify Be, and then using 6 mol/L HCl to separate and purify Al.

In some embodiments, using 6 mol/L HCl to remove carbonate in the sample includes: putting the sample particles into a beaker, adding 6 mol/L HCl, and heating in a water bath at 85° C. for 5 to 6 hours In order to effectively remove the carbonate in the sample, after repeated washing with water and drying.

In some embodiments, the use of a mixed acid 12.5 times the weight of impurities in the sample to dissolve the sample includes: placing the sample in a beaker, adding a mixed acid 12.5 times the weight of the impurities in the sample, and dissolving the sample in a water bath at 85°C for 7- During 8 hours, stirring once per hour, the mixed acid was a mixed acid of 10% HF and 10% HNO ₃ .

In some embodiments, the ultrasonic treatment includes: after washing the corroded sample, adding a 12.5% NaOH solution, ultrasonicating for half an hour, cleaning until there is no milky liquid, then adding 3 mol/L HCl, and ultrasonically treating for half an hour. Washed and dried in an incubator to obtain a quartz sample.

In some embodiments, after the ultrasonic treatment, the preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer further comprises: determining the Al content in the quartz sample, and repeating when the Al content in the quartz sample is not less than 200 ppm The etching and sonication were performed until the Al content in the quartz sample was below 200 ppm.

In some embodiments, the determination of the Al content in the sample includes: placing the quartz sample in a Teflon beaker, adding premium pure concentrated acid, heating on a heating plate at 140° C. for 3 to 4 hours, and waiting for the quartz sample to dissolve. After evaporation to dryness, add 1 ml of HNO ₃ to make the volume to 100 ml, and use an inductively coupled plasma emission spectrometer to measure the Al content.

In some embodiments, Be carrier and Al carrier are added to the quartz sample, and the quartz sample is completely dissolved by heating on a heating plate with premium pure HF to obtain a sample solution, including: weighing 20-30 g of the quartz sample Put it into a Teflon beaker, add 0.25g Be carrier and 0.5g Al carrier to the Teflon beaker, add a chemical blank to each group of samples, add 120ml of high-grade pure HF, heat on the heating plate at 140 ° C to completely dissolve the quartz sample, and put it in a Teflon beaker. The solution was evaporated to dryness at 140°C, and 10 ml of 6 mol/L HCl was added to evaporate to dryness.

In some embodiments, the use of NaOH solution to remove Fe, Ti, Ca and Mg includes: washing the bottom and wall of the Teflon beaker with 1.5 ml of 1.1 mol/L HCl to form a solution, and transferring the solution in the Teflon beaker into a centrifuge tube , repeated many times to make the solution in the centrifuge tube reach 10ml; add 12.5% NaOH solution to 20ml to the centrifuge tube, shake it up, put it into a centrifuge and centrifuge at 3500rpm for 10 minutes and pour out the clear liquid; add 5ml6mol/ L of HCl, adjust the pH value to 8-9 with 30% ammonia water to precipitate the solution in the centrifuge tube, put it in a centrifuge and centrifuge at 3500rpm for 10 minutes, then pour out the clear liquid; add 1.1mol/L HCl to the centrifuge tube to 20ml , shake to dissolve the precipitate completely.

In some embodiments, the described use of ion exchange resin to separate and purify Be and Al includes:

The 20ml solution obtained after removing Fe, Ti, Ca and Mg was loaded into the cation exchange column until it was dripping completely;

Add 40ml of 1.1mol/L HCl to the cation exchange column to form a 60ml solution, continue to add 1.1mol/L of HCl to 100ml, intercept the 100ml solution and keep it in other Teflon beakers for precipitating Be ions;

Add 1.1mol/L of HCl to 20ml to the cation exchange column to make the ion exchange resin transition from weak acid to strong acid, then add 80ml of 6mol/L HCl to retain this 80ml solution in other Teflon beakers through the ion exchange column for precipitation Al ions.

In some embodiments, using the solution obtained by separating and purifying Be and Al to prepare Be oxide and Al oxide comprises: evaporating the solution in a Teflon beaker obtained by separating and purifying Be and Al; Rinse the Teflon beaker for several times, pour the solution obtained from the washing into a 15ml centrifuge tube; add 15% ammonia water to the 15ml centrifuge tube, adjust the pH value to 8-9, and make Be(OH) ₂ and Al(OH) ₃ all precipitate , put it into a centrifuge at 3500rpm for 10 minutes, and then pour out the supernatant; dissolve the precipitate in a 15ml centrifuge tube with 6ml of 1.1mol/L HCl, add 15% ammonia water, and precipitate Be(OH) ₂ , Al(OH) again ) ₃ , put into a centrifuge at 3500rpm for 10 minutes and pour out the supernatant; add 6ml of absolute ethanol, shake to disperse the precipitation, put it in a centrifuge and centrifuge at 3500rpm and pour out the ethanol; put the precipitate Be(OH) ) ₂ and Al(OH) ₃ were dried in a vacuum oven, moved into a quartz crucible, and calcined in a muffle furnace at 920 °C for 30 minutes or at 750 °C for 1 hour to make the precipitates Be(OH) ₂ and Al(OH) ₃ Converted to BeO and Al ₂ O ₃ .

Experiments have verified that the present disclosure can effectively remove magnetic substances and atmospheric origin ¹⁰ Be in the sample, well separate Be and Al, and at the same time can effectively improve the recovery rate of Be.

Description of drawings

The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure, are included to provide a further understanding of the disclosure, and are incorporated in and constitute the present specification part of the manual.

1 is a schematic flow diagram of a preparation method for accelerator mass spectrometer measurement ^{of10Be and26Al} samples according to some embodiments of the present disclosure;

2 is a schematic diagram of sample particles of 4 different particle sizes after crushing and sieving according to some embodiments of the present disclosure;

3 is a schematic diagram of precipitation during removal of Fe, Ti, Ca and Mg in accordance with some embodiments of the present disclosure;

4 is a schematic diagram of ion exchange resin separation and purification of Be and Al in accordance with some embodiments of the present disclosure;

Figure 5a is a schematic diagram of the content change of Al and Be when 3 mol/L HCl is used to elute Be ions;

Figure 5b is a schematic diagram of the change in element content when 1.1 mol/L HCl is used to 160 ml and then 3 mol/L HCl is used to separate Be and Al;

Figure 6a is a schematic diagram of the content changes of Al and Be when 1.1 mol/L HCl is used to elute Be ions;

Figure 6b is a schematic diagram of the change in element content when 1.1 mol/L HCl is used to 100 ml and then 6 mol/L HCl is used to separate Be and Al;

Detailed ways

The present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the related content, but not to limit the present disclosure. In addition, it should be noted that, for the convenience of description, only the parts related to the present disclosure are shown in the drawings.

It should be noted that the embodiments of the present disclosure and the features of the embodiments may be combined with each other unless there is conflict. The technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

Unless otherwise stated, the illustrated exemplary embodiments/embodiments are to be understood as exemplary features providing various details of some ways in which the technical concept of the present disclosure may be implemented in practice. Therefore, unless otherwise stated, the features of various embodiments/embodiments may be additionally combined, separated, interchanged and/or rearranged without departing from the technical concept of the present disclosure.

The use of cross-hatching and/or hatching in the drawings is generally used to clarify boundaries between adjacent components. As such, unless stated, the presence or absence of cross-hatching or shading does not convey or represent any particular material, material properties, dimensions, proportions, commonalities between the illustrated components and/or any other characteristics of the components, any preferences or requirements for attributes, properties, etc. Furthermore, in the drawings, the size and relative sizes of components may be exaggerated for clarity and/or descriptive purposes. When example embodiments may be implemented differently, the specific process sequence may be performed in a different order than described. For example, two consecutively described processes may be performed substantially concurrently or in the reverse order of that described. In addition, the same reference numerals denote the same components.

When an element is referred to as being "on" or "over", "connected to" or "coupled to" another element, the element can be directly on, directly connected to, the other element Either directly coupled to the other component, or intermediate components may be present. However, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no intervening elements present. To this end, the term "connected" may refer to a physical connection, electrical connection, etc., with or without intervening components.

For descriptive purposes, the present disclosure may use terms such as "under", "under", "under", "under", "above", "on", "at" Spatially relative terms such as "on", "upper" and "side (eg, in "sidewall")", etc., to describe the relationship between one element and another (other) element as shown in the figures relation. In addition to the orientation depicted in the figures, spatially relative terms are intended to encompass different orientations of the device in use, operation, and/or manufacture. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of "above" and "below." In addition, the device may be otherwise oriented (eg, rotated 90 degrees or at other orientations) and, as such, the spatially relative descriptors used herein should be interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms "a" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. Furthermore, when the terms "comprising" and/or "comprising" and their variants are used in this specification, it is indicated that the stated features, integers, steps, operations, parts, components and/or groups thereof are present, but not excluded One or more other features, integers, steps, operations, parts, components and/or groups thereof are present or additional. Note also that, as used herein, the terms "substantially," "approximately," and other similar terms are used as terms of approximation and not as terms of degree, as they are used to explain what one of ordinary skill in the art would recognize Inherent deviations from measured, calculated and/or provided values.

FIG. ¹ is a schematic flowchart of a preparation method for measuring10Be ^and26Al samples by an accelerator mass spectrometer according to an embodiment of the present disclosure.

In some embodiments, the following solutions can be pre-configured before sample preparation:

The preparation method of the present disclosure may include four parts, namely crushing and magnetic separation, quartz extraction and purification, separation and purification of Be and Al, and preparation of BeO and Al ₂ O ₃ target samples. The specific embodiment of the preparation method of the present disclosure will be described in detail below with reference to FIG. 1 .

Referring to FIG. 1 , the process of the preparation method S10 for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer may include the following steps:

Step S12, obtaining sample particles by crushing and magnetic separation;

In some embodiments, the rock containing quartz can be pulverized, sieved, adsorbed magnetic minerals and sorted by a magnetic separator in sequence to obtain sample particles with a particle size of 0.1-0.6 mm;

In some embodiments, the selected rock with high quartz content is crushed with a hammer, crushed with a pulverizer (for example, Retsch DM200, Germany), sieved with sieves with different apertures, and sample particles with a particle size of 0.1mm-0.6mm are selected as the sample particles. Subsequent processing. Figure 2 shows the sample particles of 4 different particle sizes after crushing and sieving. Preferably, sample particles with a particle size of 0.25-0.5 mm are selected.

In some embodiments, after the sample particles are selected, the following treatment can be performed to better remove the magnetic separation substances: use a permanent magnet to adsorb the magnetic minerals in the sample particles, and then use a magnetic separator (for example, S.G.Frantz Co LB- 1 magnetic separator) for sorting to remove insoluble iron-bearing minerals such as biotite, feldspar and amphibole in the sample particles. Preferably, the forward tilt angle and the side tilt angle of the magnetic separator can be set to 10°, and the current can be set to 1.75A.

Step S14, HCl treatment;

In some embodiments, 6 mol/L HCl can be used to remove carbonates from the sample particles.

Specifically, put the sample particles crushed and magnetically separated in step S12 into a beaker, add an appropriate amount of 6 mol/L HCl, and heat in a water bath at 85°C for 5 to 6 hours, until the solution turns yellow-green or no 6 mol/L hydrochloric acid is added. CO ₂ was generated to effectively remove carbonates from the sample particles, after which they were rinsed with water 3 times, dried, and weighed.

In some embodiments, the reaction time of this step can be set to 5-6 hours. If the solution still does not turn yellow-green after 6 hours, the reaction time can be appropriately extended.

In some embodiments, when 6 mol/L HCl is added, the sample is submerged. Specifically, the required amount of hydrochloric acid can be calculated according to the impurity content of the sample. For example, if the impurity content is large, more hydrochloric acid can be added, and if the impurity content is small, less hydrochloric acid can be added. For example, generally, 300ml-400ml of 6mol/L HCl can be added, and if the amount of hydrochloric acid is found to be insufficient during the reaction, it can be added.

In some embodiments, it can be heated in a constant temperature water bath at 85°C to effectively remove carbonates in the sample. Afterwards, rinse with tap water or pure water for 3-4 times and dry. Here, drying is to weigh the quality of the sample and observe the impurity content in the sample, so that mixed acid can be added as appropriate according to the impurity content in the subsequent processing.

In some embodiments, the beaker can be shaken every 1 hour while heating in a water bath to allow the sample to react more fully. After the sample is in the water bath, its mixed solution turns yellow-green, indicating that the acidification treatment is complete.

Step S16, mixing acid etching and ultrasonic treatment to obtain a pure quartz sample;

In some embodiments, in step S16, a mixed acid of 12.5 times the weight of impurities in the sample particles can be used to dissolve the sample particles, and then ultrasonically process to obtain a quartz sample with an Al content of less than 200 ppm.

In some embodiments, using a mixed acid that is 12.5 times the weight of impurities in the sample particles to etch the sample particles may include: estimating the impurity content of the sample particles by microscopic or visual observation, placing the sample particles in a plastic cup, according to the impurity content of the sample particles. A mixed acid of about 12.5 times the weight of impurities was added, and the mixture was dissolved in a water bath at 85° C. for 8 hours with stirring once per hour. The mixed acid was a mixed acid of 10% HF and 10% HNO ₃ .

In the specific operation, the sample treated with 6mol/L hydrochloric acid can be weighed, transferred from the glass cup to a plastic beaker, and rinsed in with a washing bottle. The higher purity of quartz is 70g, and the lower one is 100g.

In some embodiments, when the weighed sample is heated in a water bath at 85°C, the amount of mixed acid to be added to each sample can be obtained according to the following formula (1), and the corresponding mixed acid is weighed with a balance and added to a plastic beaker, Shake well, cover, and heat in an 85°C water bath for 7-8 hours, shaking every hour.

M1*x*12.5=M2 (1)

Among them, M1 represents the mass of the sample, M2 represents the mass of the mixed acid, x represents the impurity content of the sample, for example, it can be 20%, and "*" represents the multiplication. Here, the impurity content of the sample can be estimated by observation with a microscope, or with the naked eye when a microscope is not available.

Preferably, at the beginning, the sample contains a lot of impurities, and 400 g of mixed acid can be directly added, up to 500 g of mixed acid.

In some embodiments, after the heating of the water bath is completed, the plastic cup can be taken out, an appropriate amount of ultrapure water can be added (the amount of ultrapure water and mixed acid treatment can be equal), and it can be left to cool. Alternatively, use a small watering can filled with ultrapure water to flush the sides and lids of the cup to protect the experimenter and prevent the mixed acid vapors from choking. After sufficient cooling, wash with ultrapure water 3-5 times and transfer to a glass beaker.

The experimental results show that more than 90% of magnetic separation substances, aluminosilicate minerals such as feldspar, and atmospheric origin ¹⁰ Be can be removed at one time through sieving, permanent magnet adsorption, magnetic separator separation, and mixed acid etching.

In some embodiments, the ultrasonic treatment may include: after washing the etched sample, adding a 12.5% NaOH solution, ultrasonicating for half an hour, and cleaning until there is no milky liquid, then adding 3 mol/L HCl, and cleaning after ultrasonic treatment for half an hour. And put it into an incubator to dry to obtain a quartz sample.

Preferably, the sample after mixed acid etching is repeatedly rinsed with high-purity water, and then 12.5% NaOH solution is added. If the sample is not over, it is repeatedly washed with high-purity water after ultrasonic treatment for half an hour until there is no milky liquid. After sonicating for half an hour, wash the samples with high-purity water for 3 to 5 times, put them in a constant temperature oven (for example, an oven at 80°C) to dry, and finally pack them into bags to mark the serial number and quality.

Preferably, the impurities in the sample can be estimated by observation with a microscope or the naked eye. If there are impurities in the sample, repeat step S16, and continue to purify in the order of mixed acid etching and ultrasonic treatment until the amount of impurities in the sample is less than 10%. .

In actual operation, the sample is observed with a microscope, and the quartz is translucent and slightly glossy. When observing, a small amount of sample can be placed on a weighing paper and observed on a microscope. Move back and forth to observe the quartz grains on the edge to roughly estimate the quartz content. During excessive etching, the quartz particles are too small, as long as the quality is sufficient, it will not affect the subsequent tests. When quartz is overetched, the quartz grains appear dull and dull.

In practical applications, pure quartz can be obtained after 3 to 4 times of mixed acid etching and ultrasonic treatment. If the quartz is manually selected, it generally only needs to be done once.

In some embodiments, after step S16, the method may further include: measuring the Al content in the quartz sample, and repeating the dissolution and ultrasonic treatment when the Al content in the quartz sample is not less than 200 ppm, until the Al content in the quartz sample is less than 200 ppm.

In some embodiments, the Al content can be determined by inductively coupled plasma optical emission spectrometer (ICP-OES) to complete the quartz extraction and purification. Preferably, determining the Al content in the sample may include: putting the quartz sample into a Teflon beaker, adding premium pure concentrated acid, heating on a heating plate at 140°C for 3 to 4 hours, and after the quartz sample is dissolved and evaporated to dryness, adding 1 ml of HNO ₃ The volume was adjusted to 100ml, and the Al content was measured using an inductively coupled plasma emission spectrometer.

Preferably, weigh 0.5g of quartz sample and put it into a Teflon beaker (or, a polytetrafluoroethylene beaker can also be used), add premium pure concentrated acid (for example, it can be 6ml HF+1ml HCl+1ml HNO3) acid), use a 140°C heating plate to heat the Teflon beaker for 3 to 4 hours, after the quartz is dissolved and evaporated to dryness, add 1ml of HNO ₃ to dilute to 100ml, when the Al content in the quartz sample determined by ICP-OES is less than 200ppm, it is complete Quartz extraction and purification, while eliminating the influence of atmospheric origin ¹⁰ Be. If the Al content in the quartz sample determined by ICP-OES is not less than 200 ppm, step S16 may be repeated until the Al content in the quartz sample is less than 200 ppm.

Here, a glass rod can be used to drain the volume into a 100ml volumetric flask, and the 100ml volumetric flask can be adjusted to 100ml, and shake well.

Step S18, dissolving the quartz sample;

In some embodiments, step S18 may include: adding Be carrier and Al carrier to the quartz sample, heating the quartz sample with premium pure HF on a heating plate to completely dissolve the quartz sample to obtain a sample solution, and evaporating the sample solution to dryness. Preferably, it may include: weighing 20-30g of quartz samples into a Teflon beaker, adding 0.25g Be carrier and 0.5g Al carrier, adding a chemical blank to each group of samples, adding 120ml of high-grade pure HF, and adding 0.25g of Be carrier and 0.5g of Al carrier to each group of samples. The quartz sample was completely dissolved by heating at 140°C, the solution was evaporated to dryness at 140°C, and 10 ml of 6 mol/L HCl was added to evaporate to dryness. Here, excess HF can be driven off by evaporation to dryness.

For example, weigh 30g of purified quartz sample, add 0.25g ⁹ Be carrier and 0.5g ²⁷ Al carrier, add a chemical blank to each group of samples, add 120ml of premium pure HF, put it on a heating plate and heat at 140℃ to completely dissolve the quartz , lift off the half cover and evaporate the solution to dryness at 140°C, add 10ml of 6mol/L HCl and evaporate to dryness.

For example, when extracting Be, turn on the balance in advance (preheat for about 2 hours), weigh about 20-30g of purified quartz sample, add 0.2-0.25g of carrier 9Be, and place the above sample on a flat-plate electric furnace (open to about 140 ℃), and add 40% HF (each gram of quartz corresponds to 4ml of 40% HF), add it in two times, add 2/3 of the total amount for the first time, cover it (the cover is washed with ultrapure water) and heat for about 6-7 hours, add the remaining 1/3 HF for the second time, wait for the reaction for 6-7 hours, open the 1/5 cup of the lid, until evaporated to dryness. Then, add 10 ml of 6 mol/L hydrochloric acid (about covering the bottom of the cup), and after half an hour, leave the lid open for about 2 hours to evaporate to dryness.

The carrier ²⁷ Al can be added (approximately 0.5 g) if burial age needs to be measured. One blank control should be added to each group of samples. If the exposure age is measured, add 0.2-0.25g carrier ⁹ Be, and if the burial age is measured, add 0.2-0.25g carrier ⁹ Be and about 0.5g carrier ²⁷ Al.

In practice, if the sample is small, eg only 20 g, all HF can be added at one time.

Step S11, removing Fe, Ti, Ca and Mg;

In some embodiments, Fe, Ti, Ca, and Mg can be removed using a NaOH solution.

In some embodiments, step S11 may specifically include: washing the bottom and the wall of the Teflon beaker with 1.5 ml of 1.1 mol/L HCl to form a solution, moving the solution in the Teflon beaker into a centrifuge tube, and repeating many times until the solution in the centrifuge tube reaches 10ml; add 12.5% NaOH solution to the centrifuge tube to 20ml, shake well, put it in a centrifuge and centrifuge at 3500rpm for 10 minutes, pour out the clear liquid; add 5ml of 6mol/L HCl to the centrifuge tube, adjust the pH with 30% ammonia water When the value reaches 8 to 9, the solution in the centrifuge tube is precipitated. Put it into a centrifuge and centrifuge at 3500rpm for 10 minutes, and then pour out the supernatant; add 1.1mol/L HCl to 20ml to the centrifuge tube, and shake to completely dissolve the precipitate.

Exemplarily, taking the extraction of Be as an example, the specific implementation process of step S11 may include the following steps:

Step a1, add 1.5ml of 1.1mol/L hydrochloric acid to clean the wall and bottom of the Teflon beaker (total amount is about 5-10ml), transfer it into a 50ml centrifuge tube with a numbered number, and pour it slowly during the transfer process.

Step a2, add 12.5% NaOH solution according to the ratio of 1:1 to the sample obtained in step S18, shake the centrifuge tube to make a full reaction, and the blank control (Blank) does not need to add NaOH solution, put the same amount of sample symmetrically into the centrifuge Centrifuge at 3500 rpm for 10 min. After centrifugation, transfer the supernatant to a new 50ml centrifuge tube with corresponding number, and discard the old tube containing the precipitate. The precipitate is usually hydroxides of Fe, Ti, Ca, Mg, etc.

Step a3, add the hydrochloric acid of 5ml 6mol/L in the clear liquid of step a2 gained, the blank control does not need to add 6mol/L hydrochloric acid, use pH test paper to test the pH value, make it acidic (the test paper turns red), shake and mix, and then go to. Add 10 drops of 30% ammonia water (or about 1.25-2ml), adjust the pH value to 8-9 (ie, the test paper turns green), and it can be seen that there is precipitation (flocculent) in the solution. Put it in a centrifuge at 3500rpm for 10 minutes, pour out the supernatant (can be poured into the waste tube before), and leave the precipitate (pay attention to check the amount of the precipitate, if it is too small, the pH value may not be adjusted to 8-9 , needs to be reconditioned and centrifuged). Finally, 1.1N hydrochloric acid was added to the precipitate to make up to 20ml, and the solution was completely dissolved by shaking.

Figure 3 shows a schematic diagram of the precipitation during the removal of Fe, Ti, Ca and Mg.

Step S13, activate the particle exchange column, and use ion exchange resin to separate and purify Be and Al;

In some embodiments, using an ion exchange resin to separate and purify Be and Al in step S13 may include: firstly using 1.1 mol/L HCl to separate and purify Be, and then using 6 mol/L HCl to separate and purify Al.

Figure 5a shows a schematic diagram of the content changes of Al and Be when eluting with 3 mol/L HCl, and Figure 5b shows the separation of Be and Al with 1.1 mol/L HCl to 160 ml and then 3 mol/L HCl. Schematic diagram of changes in element content. It can be seen from Figure 5a that although 3 mol/L hydrochloric acid quickly elutes Be and Al ions, the overlap cannot be separated. It can be seen from Figure 5b that Be and Al can be separated by using 1.1 mol/L hydrochloric acid to 160 ml and then 3 mol/L hydrochloric acid, but at the same time some Mg ions are eluted.

Figure 6a shows a schematic diagram of the changes in the content of Al and Be when eluted with 1.1 mol/L HCl. It can be seen from Figure 6a that 1.1 mol/L hydrochloric acid can well separate Be ions.

Figure 6b shows a schematic diagram of the change in element content when using 1.1 mol/L HCl to 160 ml to separate Be and then use 6 mol/L HCl to separate Al. It can be seen from Figure 6b that Be and Al can be well separated by using 1.1mol/L hydrochloric acid to 160ml and then 6mol/L hydrochloric acid, and the content of other elements is very low, and the degree of purification of Be and Al is high.

In some embodiments, the process of activating the ion exchange column may include: sequentially adding 40 ml of ultrapure water to the ion exchange column (φ1.5×10 cm), and washing the ion exchange column once with 40 ml of HCl with a concentration of 6N and 0.1N, respectively. , to restore the adsorption activity, the ion exchange resin is Dowex 50W×8 (H ⁺ ) type, and the particle size is 50-100 mesh (mesh).

In some embodiments, the process of separating and purifying Be and Al using an ion exchange resin may include: loading 20 ml of the solution obtained after removing Fe, Ti, Ca and Mg into a cation exchange column until it is dripped; adding 40 ml of the solution to the cation exchange column .1mol/L HCl forms a 60ml solution, continue to add 1.1mol/L HCl to 100ml, intercept the 100ml solution and keep it in other Teflon beakers for precipitation of Be ions; add 1.1mol/L to the cation exchange column. L of HCl to 20 ml to make the ion exchange resin transition from a weak acid (eg, 1.1 mol/L weak acid) to a strong acid (eg, 6 mol/L weak acid), and then add 80 ml of 6 mol/L HCl to pass the 80 ml solution through an ion exchange column Reserved for other Teflon beakers for precipitation of Al ions.

That is, 20ml of the solution obtained in step S11 can be loaded into the cation exchange column, and 40ml of 1.1mol/L HCl is added until the dripping is finished, and the 60ml solution is stored in the same glass beaker, and the ion exchange column is closed when about 2 marks are left; Then, add 100ml of 1.1mol/L HCl (can use a 50ml centrifuge tube to measure), keep this part of the solution in a Teflon beaker to precipitate Be ions; continue to add 20ml of 1.1mol/L HCl to the cation exchange column and store it in In order to make the ion exchange resin transition from weak acid (for example, 1.1mol/L weak acid) to strong acid (for example, 6mol/L weak acid) in the beaker before, add 80ml 6mol/L HCl to pass through the ion exchange column, and keep the 80ml solution in Another Teflon beaker for precipitation of Al ions. Figure 4 shows a schematic diagram of the separation and purification of Be and Al by ion exchange resins.

In step S15, Be oxide and Al oxide are prepared, that is, Be oxide and Al oxide are prepared using a solution obtained by separating and purifying Be and Al.

In some embodiments, step S15 may specifically include: evaporating to dryness the solution in the Teflon beaker obtained by separating and purifying Be and Al; rinsing the Teflon beaker with 1 ml of 1.1 mol/L HCl, and pouring the solution obtained from the washing into a 15 ml centrifuge tube; Add 15% ammonia water to a 15ml centrifuge tube, adjust the pH to 8 to 9, make Be(OH) ₂ and Al(OH) ₃ all precipitate, put it into a centrifuge at 3500rpm for 10 minutes, and pour out the clear liquid; Dissolve the precipitate in a 15ml centrifuge tube with 6ml 1.1mol/L HCl, add 15% ammonia water, precipitate Be(OH) ₂ and Al(OH) ₃ again, put it in a centrifuge at 3500rpm for 10 minutes, and pour out the clear liquid ; Add 6ml of absolute ethanol, shake to disperse the precipitation, put it into a centrifuge and pour out the ethanol after centrifugation at 3500 rpm; put the precipitate Be(OH) ₂ and Al(OH) ₃ into a vacuum oven (about 60 ° C) to dry Dry (dry for about 4 to 5 hours), transfer to a quartz crucible, and calcine in a muffle furnace at 920°C for 30 minutes or 750°C for 1 hour to convert the precipitates Be(OH) ₂ and Al(OH) ₃ into BeO and Al ₂ O ₃ in order to use BeO, Al ₂ O ₃ to make targets.

In some embodiments, before moving into the quartz crucible, the quartz crucible soaked in 3% dilute nitric acid may be rinsed with ultrapure water, and then placed in an oven for drying.

As a rock-forming mineral, quartz is widely distributed, and it is easy for other rocks to experience complex geological movements and actions together to form minerals and rocks with complex components, often associated with biotite, feldspar, amphibole and other magnetic substances. The present disclosure adopts three steps of sieving, permanent magnet adsorption, and magnetic separator sorting to effectively remove the magnetic substances in the samples. It is found through experiments that the preparation method of the present disclosure can remove more than 90% of the magnetic substances in the samples at one time.

The single-element standard solution of simulated impurity interference elements B, Fe, Mg, and Ti was prepared into a mixed standard solution. The mass of each element was 0.3 mg. In order to be consistent with the actual experimental chemical treatment process, ⁹ Be carrier and ²⁷ Al were added to the mixed standard solution. Carrier, add 12.5% NaOH at a ratio of 1:1 to precipitate Fe, Ti, Ca, Mg and other hydroxides, centrifuge to retain the supernatant to restore the acidity, add ammonia water to adjust the pH value to 8-9 to precipitate, retain the precipitate by centrifugation and add 1.1mol /L HCl to 20ml, shake to dissolve the precipitate completely. 20ml of the mixed standard solution after treatment was loaded into anion exchange resin to further remove Fe and Ti, 30ml of 6mol/L HCl was used to rinse the anion resin and the eluate was intercepted. Add 1.1mol/L HCl to 20ml to load the cation exchange resin, 160ml 1.1mol/L HCl to elute the cation exchange resin to separate Be, and intercept 10ml of sample; then use 80ml 6mol/L HCl to elute the cation exchange resin to separate Al, ICP -OES determination of Be, Al, B, Fe, Mg, Ti in the eluate.

The experiment found that the eluate of the anion resin is a mixed solution of Be and Al, and the Be and Al need to be separated by a cation exchange resin. The leaching solution of the cation exchange resin was tested by segmented ICP-OES, each 10ml mixed standard solution was a test object, and the leaching curves of Be and Al were drawn through the changes of Be and Al content in each segment of the solution, as shown in Figure 6b The schematic diagram of the leaching curves of Be and Al is drawn.

As shown in Figure 6b, the peaks of Be and Al content do not overlap, and the separation is very good. The content of B, Mg, Fe, and Ti in the eluate is very low. Be, the mass of Be in the eluate is 0.518mg, the recovery rate is 83%, the mass of Be in the 30-150ml eluate is 0.514mg, the quality of Be in this part of the eluate is good, and the content of B and other interfering elements Low, can guarantee the later AMS measurement requirements. After washing with 160ml 1.1mol/L HCl, 80ml 6mol/L HCl was used to wash the cation exchange resin to separate Al, the mass of Al in the eluate was 0.168mg, the recovery rate was only 33%, and the peak of Al was concentrated in the 170th In ~230ml of leaching solution, the mass of Al in the leaching solution is 0.147 mg, which meets the requirements of later AMS measurement. In the 170-190ml eluate, although a small amount of Fe is eluted out, the mass of Fe is less than 10 μg, which does not affect the subsequent AMS measurement of ²⁶ Al.

The AMS measurement process of the sample on the accelerator mass spectrometer is as follows: BeO and Al ₂ O ₃ prepared from the rock sample according to the process shown in Fig. 1 are ground into powders, which are respectively proportional to the Nb powder (for example, Al ₂ O ₃ :Nb= 1:2, BeO:Nb=1:4) uniformly mixed, and pressed into a standard copper target cone for AMS measurement. Al- and BeO- negative ions are extracted separately, accelerated by a series of voltages, and stripped by Ar gas at the accelerator end to decompose possible interfering molecules (eg, ¹² C ¹⁴ N and ⁹ BeH). The beam currents of ²⁷ Al ⁺ and ⁹ Be ⁺ after stripping were measured with an adjustable bias Faraday cup. A multi-anode gas ionization chamber at the end of the beam identifies and detects ²⁶ Al ⁺ and ¹⁰ Be ²⁺ (eg, after selective foil degradation). The ratios of ²⁶ Al/ ²⁷ Al and ¹⁰ Be/ ⁹ Be can be calculated from the ²⁶ Al ⁺ and ¹⁰ Be ²⁺ counts measured in the gas ionization chamber and the ²⁷ Al ⁺ and ⁹ Be ⁺ beam currents measured by the biased Faraday cup.

Two rock samples at the northern foot of the Tianshan Mountains were purified by quartz, ^purified Be, and ^Al to make ^BeO and ^Al ₂ O ₃ target samples, and the AMS measurement was carried out. ^10-15 and 2.49× ^10-14 . Compared with the measurement results of the present disclosure and other preparation methods, the blank value of ¹⁰ Be/ ⁹ Be in the measurement results of the present disclosure is comparable, and the blank value of ²⁶ Al/ ²⁷ Al is improved by an order of magnitude, which may be comparable to the recovery of Al Low rate, incomplete precipitation and other factors. Table 1 lists the AMS measurement results. The ratios of ¹⁰ Be/ ⁹ Be and ²⁶ Al/ ²⁷ Al were calibrated with the standards produced by the University of California, Berkeley, respectively. According to the quartz, carrier concentration and mass, and the ratio of ¹⁰ Be/ ⁹ Be, Balco was used. The web program of et al., calculated the exposure age of the samples and obtained an exposure age of 15.45 ± 2.13 ka.

Table 1

In the description of this specification, reference to the terms "one embodiment/mode", "some embodiments/modes", "example", "specific example" or "some examples", etc. are meant to be combined with the embodiment/mode or A particular feature, structure, material, or characteristic of the example description is included in at least one embodiment/mode or example of the present disclosure. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment/mode or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments/means or examples. Furthermore, those skilled in the art may combine and combine the different embodiments/modes or examples described in this specification and the features of the different embodiments/modes or examples without conflicting each other.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Those skilled in the art should understand that the above-mentioned embodiments are only for clearly illustrating the present disclosure, rather than limiting the scope of the present disclosure. For those skilled in the art, other changes or modifications may also be made on the basis of the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims (10)

1. a kind of preparation method that is used for accelerator mass spectrometer to measure ¹⁰ Be and ²⁶ Al sample, is characterized in that, comprises: The rock containing quartz is pulverized, sieved, adsorbed magnetic minerals and sorted by a magnetic separator in sequence to obtain sample particles with a particle size of 0.1mm to 0.6mm; Use 6mol/L HCl to remove carbonate in the sample particles; Etch the sample particles with a mixed acid 12.5 times the weight of impurities in the sample particles, and obtain a quartz sample with an Al content of less than 200 ppm after ultrasonic treatment; Add Be carrier and Al carrier to the quartz sample, use high-grade pure HF on a hot plate to completely dissolve the quartz sample to obtain a sample solution, and evaporate the sample solution to dryness; Use NaOH solution to remove Fe, Ti, Ca and Mg; Activate the ion exchange column, use ion exchange resin to separate and purify Be and Al; Use the solution obtained by separating and purifying Be and Al to prepare Be oxide and Al oxide; Wherein, using ion exchange resin to separate and purify Be and Al includes: firstly using 1.1 mol/L HCl to separate and purify Be, and then using 6 mol/L HCl to separate and purify Al. 2. the preparation method for measuring ¹⁰ Be and ²⁶ Al sample by accelerator mass spectrometer according to claim 1, it is characterized in that, described using the HCl of 6mol/L to remove carbonate in the sample, comprises: described sample The particles were put into a beaker, 6 mol/L HCl was added, and heated in a water bath at 85 °C for 5 to 6 hours to effectively remove carbonates in the samples, and then rinsed repeatedly with water and dried. 3. The preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer according to claim 1, characterized in that, using 12.5 times the mixed acid of the impurity weight in the sample to dissolve the sample, comprising: putting the sample into Add a mixed acid 12.5 times the weight of impurities in the sample into a beaker, and dissolve in a water bath at 85°C for 7-8 hours, stirring once per hour during this period. The mixed acid is a mixed acid of 10% HF and 10% HNO ₃ . 4. The preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer according to claim 1, wherein the ultrasonic treatment comprises: after the etched sample is rinsed clean, adding 12.5% NaOH solution, ultrasonicating After treatment for half an hour, it was cleaned until there was no milky liquid, then 3 mol/L HCl was added, and after ultrasonic treatment for half an hour, it was cleaned and dried in an incubator to obtain a quartz sample. 5. The preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer according to claim 4, characterized in that, after the ultrasonic treatment, also comprising: measuring the Al content in the quartz sample, in the quartz sample When the Al content is not less than 200 ppm, the etching and ultrasonic treatment are repeated until the Al content in the quartz sample is less than 200 ppm. 6. the preparation method that is used for accelerator mass spectrometer to measure ¹⁰ Be and ²⁶ Al sample according to claim 5, it is characterized in that, described measuring Al content in the sample, comprises: described quartz sample is put into Teflon beaker, add excellent Grade pure concentrated acid, heated on a heating plate at 140°C for 3-4 hours, after the quartz sample was dissolved and evaporated to dryness, 1ml HNO ₃ was added to make up the volume to 100ml, and the Al content was measured using an inductively coupled plasma emission spectrometer. 7. The preparation method for measuring ¹⁰ Be and ²⁶ Al sample by accelerator mass spectrometer according to claim 1, characterized in that, adding Be carrier and Al carrier to the quartz sample, and using top-grade pure HF to heat on a hot plate Completely dissolving the quartz sample to obtain a sample solution, including: weighing 20-30 g of the quartz sample into a Teflon beaker, adding 0.25 g Be carrier and 0.5 g Al carrier to the Teflon beaker, and adding a chemical blank to each group of samples , add 120ml of high-grade pure HF, heat the quartz sample at 140°C on a heating plate to completely dissolve the quartz sample, evaporate the solution to dryness at 140°C, and add 10ml of 6mol/L HCl to evaporate to dryness. 8. The preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer according to claim 1, wherein the use of NaOH solution to remove Fe, Ti, Ca and Mg comprises: Wash the bottom and wall of the Teflon beaker with 1.5ml of 1.1mol/L HCl to form a solution, move the solution in the Teflon beaker into a centrifuge tube, repeat several times, and make the solution in the centrifuge tube reach 10ml; Add 12.5% NaOH solution to the centrifuge tube to 20ml, shake well, put it into a centrifuge and centrifuge at 3500rpm for 10 minutes, and then pour out the clear liquid; Add the HCl of 5ml 6mol/L to the centrifuge tube, adjust the pH value to reach 8～9 with 30% ammonia water to make the solution in the centrifuge tube precipitate, put into the centrifuge and pour out the clear liquid after 10 minutes of centrifugation at rotating speed 3500rpm; Add 1.1 mol/L HCl to 20 ml to the centrifuge tube, and shake to dissolve the precipitate completely. 9. The preparation method for measuring ¹⁰ Be and ²⁶ Al sample by accelerator mass spectrometer according to claim 1, characterized in that, described using ion exchange resin to separate and purify the solution obtained by removing Fe, Ti, Ca and Mg and Al, including: The 20ml solution obtained after removing Fe, Ti, Ca and Mg was loaded into the cation exchange column until it was dripping completely; Add 40ml of 1.1mol/L HCl to the cation exchange column to form a 60ml solution, continue to add 1.1mol/L of HCl to 100ml, intercept the 100ml solution and keep it in other Teflon beakers for precipitating Be ions; Add 1.1mol/L of HCl to 20ml to the cation exchange column to make the ion exchange resin transition from weak acid to strong acid, then add 80ml of 6mol/L HCl to retain this 80ml solution in other Teflon beakers through the ion exchange column for precipitation Al ions. 10. The preparation method for measuring ¹⁰ Be and ²⁶ Al samples by an accelerator mass spectrometer according to claim 1, wherein the preparation of Be oxide and Al oxide using the solution obtained by separating and purifying Be and Al, comprising: : The solution in the Teflon beaker obtained by separating and purifying Be and Al was evaporated to dryness; Rinse the Teflon beaker several times with 1ml of 1.1mol/L HCl, and pour the resulting solution into a 15ml centrifuge tube; Add 15% ammonia water to a 15ml centrifuge tube, adjust the pH to 8-9, make Be(OH) ₂ and Al(OH) ₃ all precipitate, put it in a centrifuge at 3500rpm for 10 minutes, and pour out the clear liquid ; Dissolve the precipitate in a 15ml centrifuge tube with 6ml of 1.1mol/L HCl, add 15% ammonia water, precipitate Be(OH) ₂ and Al(OH) ₃ again, put it in a centrifuge at 3500rpm for 10 minutes, and then pour out the clear solution. liquid; Add 6ml of absolute ethanol, shake to disperse the precipitation, put it into a centrifuge at 3500rpm and then pour out the ethanol; Put the precipitates Be(OH) ₂ and Al(OH) ₃ into a vacuum oven to dry, move them into a quartz crucible, and put them in a muffle furnace for calcination at 920 °C for 30 minutes or 750 °C for 1 hour, so that the precipitates Be(OH) ₂ and Al(OH) ₃ is converted to BeO and Al ₂ O ₃ .

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