Rapid and accurate analysis method for low content of re in geological samples

Abstract

The application provides a kind of geological sample low content Re fast and accurate analysis method, comprising: collecting sample to be determined and carrying out sample crushing;Weighing sample to be determined in plastic centrifuge tube;HCl, HNO3 and Re diluent are sequentially added to the plastic centrifuge tube;The plastic centrifuge tube is covered with a bottle cap and ultrasonic oscillation is carried out, the plastic centrifuge tube is placed in an oven at 105 DEG C to 110 DEG C and heated, and low-temperature sample dissolution is carried out;After heating is completed, the plastic centrifuge tube is placed in a centrifuge for centrifugation;The supernatant is diluted and then MC-ICP-MS is used for rapid determination of Re content.The method only uses low-cost plastic centrifuge tubes for sample dissolution, reduces the detection cost by 70% under the premise of ensuring the analysis accuracy;The Re content determination method only needs one day to complete the whole Re content process, significantly improving the single sample analysis efficiency;The Re content determination method is simple, short in determination period and cost-saving.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of Re content determination, and particularly relates to a method for rapidly and accurately analyzing low content Re in a geological sample. BACKGROUND

[0002] Currently, the existing ppb-level Re content accurate determination mainly adopts ID-NTIMS

[0003] and ID-MC-ICP-MS testing technologies, and is mainly based on a Carius tube sealed sample dissolution Re-Os isotope analysis method process. Generally, it takes two days from sample weighing to Carius tube sample dissolution to room temperature opening of the tube; from distillation separation of interference element Os to Re enrichment and purification through anion exchange method or acetone extraction, it also takes two days to prepare for machine testing; finally, it takes one day for machine testing. It takes five days for one experimental process. However, to obtain the accurate result of Re content, two processes are generally required: the first experimental process is mainly used for initial determination of the content of Re, so as to determine the optimal Re diluent ratio; the second experimental process is used for accurate determination, so as to obtain the accurate content of Re. Thus, it takes 10 days from initial determination with diluent to accurate result. Moreover, a large amount of chemical reagents and experimental equipment are consumed in the entire experimental process, and the experimental testing cost is relatively high.

[0004] The existing ppb-level Re content accurate determination method has problems of complex analysis method process, long testing period and high testing cost, and cannot meet the determination requirement of Re content of a large number of samples.

[0005] In view of the above problems, it is necessary to provide a method for rapidly and accurately analyzing low content Re in a geological sample, which is reasonable in design and effective in solving the above problems. SUMMARY

[0006] The application aims to at least solve one of the technical problems in the prior art, and provides a method for rapidly and accurately analyzing low content Re in a geological sample.

[0007] The application provides a method for rapidly and accurately analyzing low content Re in a geological sample, which comprises the following steps:

[0008] Step 1: collecting a sample to be determined and crushing the sample;

[0009] Step 2: weighing the sample to be determined in a plastic centrifuge tube;

[0010] Step 3: sequentially adding HCl, HNO3 and Re diluent into the plastic centrifuge tube;

[0011] Step four, the bottle cap is ultrasonically vibrated on the plastic centrifuge tube, the plastic centrifuge tube is heated in an oven at 105 DEG C to 110 DEG C, and semi-closed low-temperature sample dissolution is carried out;

[0012] Step five, after heating, the plastic centrifuge tube is placed in a centrifuge for centrifugation;

[0013] Step six, after the supernatant is taken and diluted, Re content is rapidly determined by MC-ICP-MS.

[0014] Optionally, 1mL to 2mL of 12mol / L HCl is added to the plastic centrifuge tube in step three.

[0015] Optionally, 1.5mL to 2mL of 16mol / L HNO3 is added to the plastic centrifuge tube in step three.

[0016] Optionally, the bottle cap is ultrasonically vibrated on the plastic centrifuge tube for 0.5h to 0.6h in step four.

[0017] Optionally, the plastic centrifuge tube is heated in an oven for 12h to 15h in step four.

[0018] Optionally, the plastic centrifuge tube is centrifuged at 2500r to 3000r for 10min to 15min in step five.

[0019] Optionally, 0.1mL to 0.2mL of the supernatant is taken and diluted 10 times to 15 times in step six.

[0020] Optionally, 0.1g to 0.2g of the sample to be determined is weighed in the plastic centrifuge tube in step two.

[0021] Optionally, the sample to be determined is crushed to less than 200 mesh in step one.

[0022] Optionally, the volume of the plastic centrifuge tube is 15mL to 20mL.

[0023] The method for rapidly and accurately analyzing low content Re in geological samples comprises the following steps: weighing a sample to be determined in a plastic centrifuge tube, sequentially adding HCl, HNO3 and Re diluent into the plastic centrifuge tube, ultrasonically vibrating a bottle cap on the plastic centrifuge tube, heating the plastic centrifuge tube in an oven at 105 DEG C to 110 DEG C, and carrying out low-temperature semi-closed sample dissolution 187 Os will affect 187Re produces interference, the chemical property of Re element is stable relative to Os element, and Re is not easy to volatilize. In the method, sample dissolution is carried out in a low-temperature semi-closed manner, which can ensure that Re is not easy to volatilize and lost, and can ensure that the interference element Os is volatilized completely and does not interfere with the determination result, thereby improving the determination precision of Re content. In addition, Os does not need to be distilled separately, time is saved, and cost is saved. Only a low-cost plastic centrifuge tube is used for sample dissolution, the detection cost is reduced by 70% under the premise of ensuring the analysis precision of ppt-ppb level. The Re content determination method can complete the whole Re content process in one day, significantly improves the single sample analysis efficiency, and the efficiency is improved by more than 5 times. The Re content determination method has the advantages of simple process, short determination period and cost saving. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a flowchart of a method for rapid and accurate analysis of low content Re in a geological sample according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0026] As Figure 1 described, the present application provides a method for rapid and accurate analysis of low content Re in a geological sample, which comprises:

[0027] Step 1, collecting the sample to be determined and crushing the sample.

[0028] Specifically, the sample to be measured is collected, washed clean with deionized water, and superfine crushed to 200 mesh or less.

[0029] In the present embodiment, two different Re content gradients of black rock series are used as samples to be measured for analysis. The black shale Re content candidate standard material B54 (standard value is 26.71 ppb; uncertainty is 0.07), and the Sichuan black shale sample DRe-1 (Re content is 91.89 ppb).

[0030] Step 2, weighing the sample to be determined in a plastic centrifuge tube.

[0031] Specifically, 0.1g-0.2g of the sample to be determined is weighed in a 15mL-20mL plastic centrifuge tube. Preferably, in the present embodiment, 0.1g of the black rock series sample is weighed in a 15mL plastic centrifuge tube.

[0032] Step 3, sequentially adding HCl, HNO3 and Re diluent to the plastic centrifuge tube.

[0033] Specifically, 1 mL to 2 mL of 12 mol / L HCl and 1.5 mL to 2 mL of 16 mol / L HNO3 are sequentially added into a plastic centrifuge tube. 185 Re diluent. Preferably, 1 mL of 12 mol / L HCl and 1.5 mL of 16 mol / L HNO3 are sequentially added into a plastic centrifuge tube.

[0034] In this embodiment, the HCl is MOS-grade HCl, which is treated by a Savillex sub-boiling distillation purification process. The purified HCl has a Re and Os content of not more than 0.03 pg. The high-purity HNO3 is heated and continuously boiled for 6 hours in a laboratory, and then repeatedly purified by a Savillex sub-boiling distillation technology to ensure that the purified HNO3 has a Re content of less than 1 pg / mL.

[0035] Step four, cover the plastic centrifuge tube with a bottle cap and perform ultrasonic oscillation, and then place the plastic centrifuge tube in an oven at 105°C to 110°C for heating to perform low-temperature semi-closed sample dissolution.

[0036] Specifically, first, cover the plastic centrifuge tube with a bottle cap and perform ultrasonic oscillation for 0.5 h to 0.6 h to perform semi-closed sample dissolution. Preferably, in this embodiment, the plastic centrifuge tube is placed in an ultrasonic oscillator for oscillation for 0.5 h.

[0037] In this embodiment, the plastic centrifuge tube is ultrasonically oscillated to make the sample fully contact with the chemical reagent and rapidly react, thereby saving time. At the same time, the Re diluent is more uniformly mixed, and the result is more accurate.

[0038] Secondly, place the oscillated plastic centrifuge tube in an oven at 105°C to 110°C for heating for 12 h to 15 h to perform low-temperature sample dissolution. Preferably, the heating temperature can be 105°C, and the heating is performed in an oven at 105°C for 12 h.

[0039] In this embodiment, low-temperature semi-closed sample dissolution is adopted, which can ensure that Re is not easily volatilized and lost, and can ensure that the interfering element Os is volatilized completely and does not interfere with the measurement, thereby improving the measurement accuracy of Re content. In addition, Os does not need to be distilled separately, thereby saving time and cost.

[0040] Step five, after heating, place the plastic centrifuge tube in a centrifuge for centrifugation.

[0041] Specifically, after heating, place the plastic centrifuge tube in a centrifuge for centrifugation at 2500 rpm to 3000 rpm for 10 minutes to 15 minutes. Preferably, place the heated plastic centrifuge tube in a high-speed centrifuge at 2500 rpm for 10 minutes.

[0042] In this embodiment, the Re-containing solution is completely separated from the reaction residue by centrifugation of the plastic centrifuge tube, so as to avoid test interference.

[0043] Step six, the supernatant is diluted and then Re content is rapidly determined by MC-ICP-MS.

[0044] Specifically, 0.1 mL to 0.2 mL of the supernatant is diluted by 10 times to 15 times. Preferably, in this embodiment, 0.1 mL of the supernatant is diluted by 10 times and then Re content is rapidly determined by MC-ICP-MS.

[0045] Re content is directly analyzed and determined by Neptune Plus type MC-ICP-MS produced by Thermo Fisher Company. The multi-reception inductively coupled plasma mass spectrometer in the Re-Os Key Laboratory of National Geological Experimental Test Center adopts energy and mass focusing modes, and is equipped with dynamic zoom technology which can improve ion mass dispersion by 17%, and is equipped with 7 Faraday cups receivers, with a fixed center channel ion counter receiver in the middle. In addition to the center cup, 4 electric motors are used to drive accurate position changes on both sides of high and low mass numbers. A electron multiplier is configured behind the center cup, and 4 ion counters are configured outside the lowest mass number cup. Faraday cup static simultaneous reception measurement and ion counter once peak quasi-static measurement can be realized. High-sensitivity JET type sampling cone and X type intercepting cone are selected, which significantly improves the sensitivity by about 2 times, the instrument measurement internal precision is less than 0.05% (Re content is greater than 1 ng / g), and the sensitivity of 1 pg Re sample can reach 60000 cps (1 mV). For Re element, static Faraday mode is used for simultaneous determination of 185 Re and 187 Re.

[0046] As shown in Table 1, the Re content data determined by the rapid and accurate analysis method of low content Re in geological samples in this embodiment and the traditional high-temperature Teflon sealed digestion tank dissolution method are compared.

[0047] Table 1 Re content results of low-temperature semi-closed and high-temperature Teflon sealed digestion tank two analysis methods

[0048]

[0049]

[0050] From table 1, the same B54 and DRe-1 samples are tested and analyzed by low-temperature semi-closed rapid digestion method and high-temperature Teflon closed digestion tank method respectively, and the results are shown in table 3.5. From the table, the Re content of B54 sample measured by low-temperature semi-closed method is 26.1ppb and 26.2ppb respectively, and the Re content of DRe-1 sample is 95.5ppb and 98.4ppb respectively; the Re content of B54 sample measured by high-temperature Teflon closed digestion tank method is 26.9ppb and 26.2ppb respectively, and the Re content of DRe-1 sample is 96.2ppb and 97.7ppb respectively. The two test results are basically consistent, which shows that under the condition of 105℃, 12h, most of Re in the sample has been basically dissolved. In addition, the low-temperature semi-closed method requires shorter time, the material is easier to obtain, and the experimental operation is simpler.

[0051] As shown in table 2, the low-temperature semi-closed rapid Re test results are compared with the standard recommended values. From table 2, the test value (26.15±0.07ppb) of B54 sample is completely consistent with the standard recommended value (26.71±0.07ppb), and the relative error is only 0.2%. The test value (96.95±2.05ppb) of DRe-1 sample is about 5% higher than the value measured by the traditional Carius tube method. The reason is that the uniformity of DRe-1 sample is not as good as that of black rock series candidate standard material B54, and there is a "chunk gold effect", but the result is still acceptable within the error range. In summary, the above results are basically consistent with the recommended values within the error range, which proves the accuracy and reliability of the low-temperature semi-closed rapid Re test method established in the embodiment.

[0052] Table 2 comparison of low-temperature semi-closed rapid Re test results and standard recommended values

[0053]

[0054] The low-content Re rapid and accurate analysis method of geological samples of the application takes the sample to be measured in a plastic centrifuge tube, adds HCl, HNO3 and Re diluent into the plastic centrifuge tube in turn, covers the plastic centrifuge tube with a bottle cap and performs ultrasonic oscillation, and puts the plastic centrifuge tube into an oven at 105℃-110℃ for heating to perform low-temperature semi-closed sample dissolution. During the mass spectrometry process 187 Os will affect 187Re produces interference, the chemical property of Re element is stable relative to Os element, and Re element is not easy to volatilize. In the method, sample dissolution is carried out in a low-temperature semi-closed manner, which can ensure that Re is not easy to volatilize and lost, and can ensure that the interference element Os is volatilized completely and does not interfere with the measurement result, and improves the determination precision of Re content. In addition, Os does not need to be distilled separately, which saves time and cost. Only a low-cost plastic centrifuge tube is used for sample dissolution, the detection cost is reduced by 70% under the premise of ensuring the analysis precision of ppt-ppb level. The Re content determination method can complete the whole Re content process in one day, significantly improves the single sample analysis efficiency, and the efficiency is improved by more than 5 times. The Re content determination method has the advantages of simple process, short determination period and cost saving.

[0055] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A rapid and accurate method for analyzing low Re content in geological samples, characterized in that, The method includes: Step 1: Collect the sample to be tested and crush it. Step 2: Weigh the sample to be tested into a 15 mL to 20 mL plastic centrifuge tube; Step 3: Add 1 mL to 2 mL of 12 mol / L HCl, 1.5 mL to 2 mL of 16 mol / L HNO3, and Re diluent to the plastic centrifuge tube in sequence; Step 4: Cap the plastic centrifuge tubes and ultrasonically vibrate them. Then, place the plastic centrifuge tubes in an oven at 105℃~110℃ and heat them for 12 h~15 h for semi-closed low-temperature sample melting. Step 5: After heating is complete, place the plastic centrifuge tubes into a centrifuge for centrifugation; Step 6: After diluting the supernatant, the Re content was rapidly determined using MC-ICP-MS; among which, Accurate measurement of all Re content can be completed in just one day, significantly improving the efficiency of single-sample analysis.

2. The method according to claim 1, characterized in that, In step four, the plastic centrifuge tube is capped and subjected to ultrasonic vibration for 0.5 h to 0.6 h.

3. The method according to claim 1, characterized in that, In step five, the plastic centrifuge tubes are placed in a centrifuge and centrifuged at 2500-3000 rpm for 10-15 minutes.

4. The method according to any one of claims 1 to 3, characterized in that, In step six, take 0.1 mL to 0.2 mL of the supernatant and dilute it 10 to 15 times.

5. The method according to any one of claims 1 to 3, characterized in that, In step two, weigh 0.1 g to 0.2 g of the sample to be tested into the plastic centrifuge tube.

6. The method according to any one of claims 1 to 3, characterized in that, In step one, the sample to be tested is pulverized to a size of less than 200 mesh.

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