Rock sample platinum group element separation and enrichment and high-precision determination method

Abstract

The embodiment of the invention provides a rock sample platinum group element separation and enrichment and high-precision determination method. The method comprises the following steps: weighing a rock geological sample, and dissolving the sample to obtain a platinum group element dissolving solution; the platinum group element dissolving solution is directly distilled to separate Os, and an Os absorption solution and a distillation residual solution containing Re and other platinum group elements are obtained respectively; redissolving the distillation residual liquid in 0.1 mol / L HCl to obtain a sample solution; adding the sample solution into a cationic resin column, and leaching, eluting and separating a matrix element, Re and other platinum group elements by using 0.1 mol / L HCl; redissolving the leachate in 0.1 mol / L HCl, adding an LN resin column, and leaching, eluting and separating residual interference elements, Re and other platinum group elements by using 0.1 mol / L HCl; and high-precision determination of Os, Re and other platinum group elements is realized. The method is easy to operate, the recovery rate of platinum group elements is high, and the removal rate of matrix elements and interference elements is high.

Description

Technical Field

[0001] The disclosed embodiments belong to the technical field of geological rock analysis, and specifically relate to a method for separation and enrichment of platinum group elements in rock samples and high-precision determination thereof. Background Art

[0002] Platinum group elements include six precious metal elements: osmium (Os), iridium (Ir), ruthenium (Ru), rhodium (Rh), platinum (Pt), and palladium (Pd). PGE is highly iron- and sulfur-loving, so it is mainly concentrated in the core and distributed in the mantle in small quantities. Among the platinum group elements, Os is related to two radioactive isotope systems at the same time, namely 187 Re- 187 Os isotope system and 190 Pt- 186 Os isotope system. Therefore, the differentiation behavior of platinum group elements during crust-mantle evolution has also become an effective tracer for studying magma genesis, mantle composition, and core-mantle interaction. Platinum group elements, as key metals, are closely related to the frontiers and major needs of earth science, but the content of platinum group elements in most geological samples is very low, often only at the pg-ng level, far below the detection line of general analytical methods. Therefore, the preferred dissolution method for obtaining high-precision platinum group element data is the Cairus tube closed dissolution method with ultra-low process blank. Combined with the isotope dilution method under the closed dissolution conditions of Carius, high-precision simultaneous determination of platinum group elements and Re-Os can be achieved, which is not only friendly to precious samples and reduces chemical processes, but also the simultaneous analysis of Re-Os and platinum group elements represents the isotopic composition characteristics of the same sample.

[0003] In the existing research on separation and enrichment methods of platinum group elements, after the rock sample is dissolved in a Carius tube, Os is separated from Re and other platinum group elements by direct distillation or carbon tetrachloride extraction, and then further enriched and purified by micro-distillation, and the Os recovery rate can reach more than 80%. For other platinum group elements, ion exchange separation and enrichment are currently mostly used. For example, in some separation methods, the platinum group elements are enriched by Te-coprecipitation after alkali dissolution or Carius tube dissolution, and then cation exchange and P507 resin are used to separate the platinum group. In another separation method, after Carius tube dissolution, cation exchange resin is used to remove most of the matrix elements, and then the tantalum reagent is adsorbed and loaded on the macroporous resin material Amberchrom CG-71 to make a BPHA resin column to further remove interfering elements such as Zr, Hf, Ta, and W. In another separation method, a method is established in which palladium reacts with chloride ions in a hydrochloric acid medium to form a complex, and the complex can be adsorbed by a macroporous weakly basic styrene anion exchange resin. In another separation method, after dissolution in a Carius tube, CCl4 is used to extract and separate Os, Re and other platinum group elements, and anion resin is used to separate and enrich Re and platinum group elements under leaching conditions of different concentrations and various acidic medium systems.

[0004] However, the existing platinum group elements separation and enrichment methods have the following problems:

[0005] 1) Using only anion exchange resin to separate and enrich platinum group elements in rock samples requires the use of a large amount of concentrated hydrochloric acid or concentrated nitric acid to elute Pt and Pd in ​​the sample, while the recovery rates of Ir, Ru, and Pd are low.

[0006] 2) Using only cationic resin to separate and enrich platinum group elements in rock samples can adsorb a large number of matrix elements such as Fe, Cu, Ni, Zn, etc., but the adsorption effect on interfering elements such as Zr, Hf, Ta, W, etc. is poor, resulting in increased isotopic interference during plasma mass spectrometry measurement and reduced accuracy and precision of platinum group element testing.

[0007] 3) When using cationic resin combined with BPHA resin for separation and enrichment of platinum group elements, BPHA resin needs to be prepared in advance and needs to be replenished after each use. Its preparation process is complicated and its service life is short, which greatly increases the analysis time and process of platinum group elements.

[0008] In view of the above problems, it is necessary to propose a method for separation and enrichment of platinum group elements in rock samples and their high-precision determination that is reasonably designed and effectively solves the above problems. Summary of the invention

[0009] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a method for separation and enrichment of platinum group elements in rock samples and high-precision determination thereof.

[0010] The present disclosure provides a method for separation and enrichment of platinum group elements in rock samples and high-precision determination thereof, the method comprising:

[0011] Step 1: Select and weigh a rock geological sample, add the weighed sample into a mixed diluent for dissolution, and obtain a platinum group element solution;

[0012] Step 2, directly distilling the platinum group element solution to separate Os, and obtaining an Os absorption solution and a distillation residue solution, respectively, wherein the distillation residue solution includes Re and other platinum group elements;

[0013] Step 3, the distillation residual liquid is sequentially subjected to acid removal, medium conversion, and acidity reduction, and then redissolved in 0.1 mol / L HCl to obtain a sample solution;

[0014] Step 4: Load the sample solution into a cationic resin column, and use 0.1 mol / L HCl for elution, so that the matrix elements and some interfering elements are adsorbed on the cationic resin column, and Re and other platinum group elements and remaining interfering elements are eluted into the elution liquid;

[0015] Step 5, the leaching liquid is redissolved in 0.1 mol / L HCl and then loaded into a LN resin column, and leaching and eluting is performed using 0.1 mol / L HCl, so that the remaining interfering elements are adsorbed in the LN resin column to obtain a solution containing Re and other platinum group elements;

[0016] Step 6: High-precision determination of Os is performed using the Os absorption solution, and high-precision determination of Re and other platinum group elements are performed using the solutions containing Re and other platinum group elements, respectively.

[0017] Optionally, in step 4, the sample solution is loaded into a cationic resin column for elution and elution, comprising:

[0018] Filling 10 mL of AG50W-X8 resin into an empty column to obtain the cationic resin column, and sequentially performing column cleaning and column balancing on the cationic resin column;

[0019] Loading the sample solution dissolved in 0.1 mol / L HCl onto the cationic resin column for sample loading;

[0020] Slowly add 20 mL of 0.1 mol / L HCl to the cationic resin column for leaching and elution, so that the matrix elements and some interfering elements are adsorbed on the cationic resin, and Re and other platinum group elements and remaining interfering elements are leached into the filtrate.

[0021] Optionally, in step 5, the filtrate is redissolved in 0.1 mol / L HCl and then loaded into a LN resin column for leaching and elution, comprising:

[0022] The filtrate was concentrated to 100 μL to 120 μL at 190° C. to 200° C. on a hot plate, and 2 ml of 0.1 mol / L HCl was added for redissolution;

[0023] Adding 0.55 g to 0.60 g of LN resin into an empty column to obtain an LN resin column, and sequentially performing column washing and column balancing on the LN resin column;

[0024] The reconstituted filtrate is loaded onto the LN resin column for sample loading;

[0025] 4 mL of 0.1 mol / L HCl was slowly added to the LN resin column for leaching, so that the remaining interfering elements were adsorbed on the LN resin column to obtain a solution containing Re and other platinum group elements.

[0026] Optionally, in step 3, the distillation residual liquid is sequentially subjected to acid removal, medium conversion, and acidity reduction and then redissolved in 0.1 mol / L HCl to obtain a sample solution, comprising:

[0027] The residual solution from the distillation was evaporated to dryness on a hot plate at 190°C to 200°C;

[0028] Add 1ml 6mol / L HCl and heat until almost dry, repeat 2-3 times to drive away HNO3;

[0029] Add 1 ml of 0.1 mol / L HCl and heat until almost dry, repeat 2 to 3 times to reduce the acidity of the distillation residue;

[0030] After adding 1 ml of 1 mol / L HCl for re-dissolution, the mixture was diluted to 10 ml to obtain the sample solution.

[0031] Optionally, in step 1, selecting and weighing a rock geological sample, adding the weighed sample to a mixed diluent for dissolution to obtain a platinum group element solution, comprises:

[0032] Accurately weigh 0.5 g to 1 g of a rock geological sample and add the sample into a Carius tube;

[0033] Accurate weighing 185 Re- 190 Os and 191 Ir- 99 Ru- 105 Pd- 198 Pt mixed diluent, adding the mixed diluent and sample dissolving reagent under the freezing condition of Carius tube;

[0034] The Cairus tube was sealed by melting and covered with a stainless steel sleeve, and placed in an oven, heated at 220° C. for 12 hours, then at 230° C. for 12 hours, and then cooled to room temperature.

[0035] Optionally, in step 2, the platinum group element solution is directly distilled to separate Os to obtain an Os absorption solution and a distillation residual solution, respectively, comprising:

[0036] The Cairus tube is opened with an acetylene flame under freezing conditions, and after returning to room temperature, Os is separated by direct distillation technology, Re and other platinum group elements are retained in the residual distillation solution, and Os is retained in a 1:1 HBr:H2O distillation absorption liquid to obtain an Os absorption liquid.

[0037] Optionally, in step six, high-precision determination of Os using the Os absorption solution comprises:

[0038] Micro-distillation technology was used to enrich and purify Os and concentrate the sample;

[0039] The concentrated sample was spotted on a high-purity Pt tape, and thermal surface ionization mass spectrometry was used to measure Os with high precision.

[0040] Optionally, in step 6, high-precision determination of Re and other platinum group elements is performed respectively by using the solution containing Re and other platinum group elements, including:

[0041] Evaporate the solution containing Re and other platinum group elements to 1 mL to 2 mL, and add 5 mL

[0042] 5% HNO3, to obtain the sample to be measured;

[0043] Using a multi-collector plasma mass spectrometer to perform high-precision determination of Re in the sample to be determined;

[0044] Tandem quadrupole plasma mass spectrometry is used to perform high-precision determination of other platinum group elements in the sample to be determined.

[0045] The rock sample platinum group element separation, enrichment and high-precision determination method of the disclosed embodiment removes matrix elements and most interfering elements through a cationic resin column, and then removes the remaining small part of interfering elements in a targeted manner through an LN resin column, thereby improving the separation and enrichment efficiency of platinum group elements; the upper column samples loaded on the cationic resin column and the LN resin column need to be redissolved in 0.1 mol / L HCl, and 0.1 mol / L HCl is used for leaching, which can better remove elements sensitive to HCl concentration, improve the removal rate of matrix elements and interfering elements and the types of interfering elements, and improve the accuracy and precision of platinum group element testing; the platinum group elements in the rock sample are separated and enriched by combining the cationic resin column and the LN resin column, which has a longer service life, a simple operation process, a higher recovery rate of platinum group elements, and a higher removal rate of matrix elements and interfering elements, and provides a new solution for the high-precision determination of platinum group elements in rock samples; the Re-Os content and isotope data of rock geological samples of the same component and the content of other platinum group elements can be obtained simultaneously by using the same chemical process, saving testing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic flow chart of a method for separation and enrichment of platinum group elements in rock samples and high-precision determination thereof according to one embodiment of the present disclosure;

[0047] Figure 2 This is a schematic diagram of the leaching curve of Re and other platinum group elements through 10 ml of cationic resin under 0.1 mol / L HCl leaching conditions according to another embodiment of the present disclosure;

[0048] Figure 3 This is a schematic diagram of the leaching curve of Re and other platinum group elements through LN resin under 0.1 mol / L HCl leaching conditions according to another embodiment of the present disclosure;

[0049] Figure 4 This is a schematic diagram of the measurement and counting of interfering elements after passing through an LN resin column under 0.1 mol / L HCl leaching conditions according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the embodiments of the present disclosure are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0051] The present disclosure provides a method for separation and enrichment of platinum group elements in rock samples and high-precision determination thereof, the method comprising:

[0052] Step 1: Select and weigh a rock geological sample, add the weighed sample into a mixed diluent for dissolution, and obtain a platinum group element solution.

[0053] Specifically, 0.5 g to 1 g of rock geological sample is accurately weighed and added to a Carius tube. 185 Re- 190 Os and 191 Ir- 99 Ru- 105 Pd- 198 Pt mixed diluent.

[0054] The Cairus tube was frozen in a liquid nitrogen-alcohol mixture, and the mixed diluent was completely transferred to the Carius tube using 2.5 ml of HCl purified by secondary sub-boiling distillation under the freezing condition of the Carius tube. After freezing, 5 ml of HNO3 and H2O2 purified by secondary sub-boiling distillation were added.

[0055] After freezing, the Cairus tube mouth was sealed by sintering, and a stainless steel sleeve was placed on the tube. The tube was placed in an oven and heated at 220° C. for 12 hours and at 230° C. for 12 hours, and then cooled to room temperature.

[0056] Step 2: directly distill the platinum group element solution to separate Os, and obtain Os absorption solution and distillation residue solution respectively, wherein the distillation residue solution includes Re and other platinum group elements.

[0057] Specifically, the Cairus tube is opened with an acetylene flame under the freezing condition of a liquid nitrogen-alcohol mixture, and after returning to room temperature, Os is separated by direct distillation technology, Re and other platinum group elements are retained in the residual solution of the distillation, and Os is retained in 1:1 HBr:

[0058] H2O is distilled from the absorption liquid to obtain Os absorption liquid.

[0059] Step 3: The distillation residual liquid is sequentially subjected to acid removal, medium conversion, and acidity reduction, and then redissolved in 0.1 mol / L HCl to obtain a sample solution.

[0060] Specifically, the residual solution from distillation is evaporated to dryness on a hot plate at 190° C. to 200° C. Preferably, in this embodiment, the solution is evaporated to dryness at 190° C.

[0061] Add 1 ml of 6 mol / L HCl and heat until almost dry, repeat 2 to 3 times to drive away HNO3. Preferably, in this embodiment, repeat 2 times to drive away HNO3.

[0062] 1 ml of 0.1 mol / L HCl is added and heated to nearly dryness, and the process is repeated 2 to 3 times to reduce the acidity of the distillation residue. Preferably, in this embodiment, the process is repeated 2 times to reduce the acidity of the distillation residue.

[0063] After adding 1 ml of 1 mol / L HCl for re-dissolution, the solution was diluted to 10 ml. That is, the distillation residue was re-dissolved in 0.1 mol / L HCl to obtain the sample solution.

[0064] Step 4: Load the sample solution into a cationic resin column and use 0.1 mol / L HCl for elution, so that the matrix elements and some interfering elements are adsorbed on the cationic resin column, and Re and other platinum group elements and remaining interfering elements are eluted into the elution liquid.

[0065] First, 10 mL of AG50W-X8 resin was filled into an empty column to obtain the cationic resin column, and the cationic resin column was sequentially cleaned and balanced.

[0066] Specifically, the empty column used was a Bio-Rad Econo-Pac chromatography empty column (14 cm in height, 1.5×12 cm polypropylene column), and the particle size of the AG50W-X8 resin was 50-100 meshes.

[0067] The AG50W-X8 cationic resin column was washed with deionized water, eluted with 60 ml 6 mol / L HCl, 30 ml deionized water, and balanced with 30 ml 0.1 mol / L HCl.

[0068] Next, the sample solution dissolved in 0.1 mol / L HCl was loaded onto the cationic resin column for sample loading.

[0069] Again, 20 mL of 0.1 mol / L HCl was slowly added to the cationic resin column for elution and leaching, so that the matrix elements and some interfering elements were adsorbed on the cationic resin, and Re and other platinum group elements and a small amount of remaining interfering elements were leached into the filtrate.

[0070] Specifically, Figure 2 As shown, 20mL 0.1mol / L HCl is slowly added to the cationic resin column for leaching and elution, wherein the matrix elements such as Li, Be, Ti, Cr, Mn, Fe, Co, Ni, Cu, and Zn are adsorbed on the AG50W-X8 cationic resin, and most of the interfering elements such as Cd, Mo, Hf, Zr, W, and Ta are adsorbed on the AG50W-X8 cationic resin, Re and other platinum group elements, and the remaining small amount of interfering elements are leached into the filtrate and collected for further treatment. Among them, Cd is very sensitive to the acidity of the cationic resin, and Cd is mainly adsorbed by the cationic resin, and can be basically removed by the cationic resin.

[0071] Among them, in the cationic resin leaching strip, an Econo-Pac chromatography empty column was used to fill 10 ml of cationic resin, and leaching was performed under 0.1 mol / L HCl conditions. The recovery rates of Re and other platinum group elements obtained were greater than 91% (as shown in Table 1). At the same time, under this condition, the removal rate of each matrix element was greater than 96% (as shown in Table 2).

[0072] Table 1 Recovery of PGE and Re under different resins and leaching conditions

[0073]

[0074] Table 2 Comparison of trace element removal rates under different HCl leaching conditions

[0075]

[0076]

[0077] In the present embodiment, matrix elements and most of interfering elements are removed by cationic resin column, the upper column sample loaded on cationic resin column is redissolved in 0.1mol / L HCl, and 20mL 0.1mol / L HCl is added to cationic resin column to carry out leaching and elution, and the element sensitive to HCl concentration can be better removed. For example, Li, Nb, Mo, Cd, Sn, W, Pb, Bi are all more sensitive to HCl acidity, and its removal rate can be reduced when HCl concentration is high, wherein, Cd and Mo are very large to PGE mass spectrometry interference, and it is necessary to ensure the removal of the element more sensitive to HCl acidity. Therefore, in the present embodiment, 20mL 0.1mol / L HCl is adopted to carry out leaching and elution of cationic resin column, improve the removal rate of matrix elements and interfering elements and the type of interfering elements, improve platinum group elements test accuracy and precision.

[0078] Step 5: The filtrate is redissolved in 0.1 mol / L HCl and loaded into a LN resin column, and leached and eluted with 0.1 mol / L HCl to allow the remaining interfering elements to be adsorbed on the LN resin column to obtain a solution containing Re and other platinum group elements.

[0079] First, the filtrate is concentrated to 100 μL to 120 μL at 190° C. to 200° C. on a hot plate, and 2 ml of 0.1 mol / L HCl is added for redissolution. Preferably, in this embodiment, the filtrate is concentrated to 100 μL at 190° C. on a hot plate.

[0080] Secondly, 0.55 g to 0.60 g of LN resin is added into an empty column to obtain an LN resin column, and the LN resin column is sequentially subjected to column washing and column equilibration.

[0081] Specifically, the empty column uses a Triskem PP chromatography empty column (inner diameter 7 mm), and the particle size of the LN resin is 100 μm to 150 μm. 0.55 g (dry weight) of LN resin is added to the Triskem PP chromatography empty column to obtain an LN resin column. The LN resin is eluted with 4 ml 6 mol / L HCl, 4 ml 2 mol / L HF, 10 ml deionized water, and 10 ml 0.1 mol / L HCl for balancing and then used.

[0082] Again, the reconstituted filtrate is loaded onto the LN resin column for sample loading.

[0083] Then, 4 mL of 0.1 mol / L HCl was slowly added to the LN resin column for leaching, so that a small amount of remaining interfering elements were adsorbed in the LN resin column to obtain a solution containing Re and other platinum group elements.

[0084] Specifically, Figure 3 As shown, 4 mL of 0.1 mol / L HCl was slowly added to the LN resin column for leaching. The five interfering elements, Zr, Mo, Hf, Ta, and W, were adsorbed on the LN resin, and the solution containing Re and other platinum group elements flowed out with the leaching liquid and was collected for further treatment. Figure 4 The figure shows the measurement counts of five interfering elements in the leaching liquid after loading 1000 ng of a mixed standard solution containing Zr, Mo, Hf, Ta, and W on the LN resin. The removal rates of the five elements are all greater than 98%.

[0085] In this embodiment, after the matrix elements and most of the interfering elements are removed by the cationic resin column, the remaining small part of the interfering elements are removed in a targeted manner by the LN resin column, thereby improving the separation and enrichment efficiency of the platinum group elements; the upper column sample loaded on the LN resin column is redissolved in 0.1 mol / L HCl, and 4 mL of 0.1 mol / L is added to the LN resin column for leaching and elution, which can better and more targetedly remove the remaining other interfering elements that are sensitive to the HCl concentration, further improve the removal rate of the matrix elements and the interfering elements and the types of the interfering elements, and improve the accuracy and precision of the platinum group element test.

[0086] Step 6: High-precision determination of Os is performed using the Os absorption solution, and high-precision determination of Re and other platinum group elements are performed using the solutions containing Re and other platinum group elements, respectively.

[0087] Wherein, in step 6, high-precision determination of Os is performed by using the Os absorption solution, comprising:

[0088] Firstly, micro-distillation technology was used to enrich and purify Os and concentrate the sample.

[0089] Specifically, the Os distilled absorption liquid was transferred to a 150ml Teflon bowl, heated on a hot plate at 150°C until about 50μL remained and transferred to a Teflon pointed bottom bottle cap, evaporated to dryness on a hot plate at 120°C, covered with 50μL of H2SO4-CrO3 mixed solution purified by distillation, and 4 times of purified HBr was added to the pointed bottom part of the pointed bottom bottle as the Os absorption liquid. The pointed bottom part was turned upside down on the cap and tightened, wrapped with aluminum foil, placed on a hot plate, and kept warm at 80°C for 4 hours. After cooling to room temperature, the H2SO4-CrO3 on the bottle cap was discarded, the pointed bottom bottle was straightened, the cap was tightened, and kept warm at 80°C in an oven for 2 hours.

[0090] Secondly, the concentrated samples were spotted on a high-purity Pt tape, and thermal surface ionization mass spectrometry was used to measure Os with high precision.

[0091] In step 6, the high-precision determination of Re and other platinum group elements is performed respectively by using the solution containing Re and other platinum group elements, including:

[0092] The solution containing Re and other platinum group elements is evaporated to 1 mL to 2 mL, and 5 ml of 5% HNO3 is added to obtain a sample to be determined. The Re in the sample to be determined is measured with high precision using a multi-collector plasma mass spectrometer. The other platinum group elements in the sample to be determined are measured with high precision using a tandem quadrupole plasma mass spectrometer.

[0093] It should be noted that in the mass spectrometry process, the 90 Zr + , 95 Mo + , 111 Cd + , 178 Hf + , 202 Hg + To monitor 90 ZrO + and 106 Cd + right 106 Pd + interference, 108 Cd + right 108 Pd + interference, 92 MoO + right 108 Pd + interference, 177,178,180 HkDJ + right 193 Ir + , 194 Pt + , 196 Pt+ interference, 198 Hg + right 198 Pt + Interference. Determination 99 Such as 101 Such as 102 Such as 105 Pd, 106 Pd, 108 Pd, 191 Ir, 193 Ir, 195 Pt, 198 When deducting interference, in addition to the interference of the interfering element oxide on PGE, 105 Pd 102 Before the measurement, the mixed PGE standard solution, the interfering element mixed standard solution, and the matrix element standard solution were measured to detect the instrument mass deviation effect, isotope ratio fractionation correction, and interfering element oxide yield correction, and the background signal was monitored by measuring 2% v / v HNO3 solution.

[0094] The following is a description of the method for separation and enrichment of platinum group elements in rock samples and their high-precision determination according to the embodiments of the present disclosure in conjunction with corresponding embodiments.

[0095] The rock sample platinum group element separation and enrichment and high-precision determination method of the disclosed embodiment were used to analyze the Re-Os isotope and PGE content of three international standard samples of rock samples of different lithologies, namely BHVO-2 (basalt), TDB-1 (diabase), and UMT-1 (ultramafic rock). The Re-Os isotope data of the three international standard samples are shown in Table 3, and the Re, Os content and isotope ratio results are consistent with the recommended values ​​within the error range. The PGE isotope data of the three international standard samples are shown in Table 4, and the Pt, Pd, Ru, and Ir content results are consistent with the recommended values ​​within the error range.

[0096] Table 3 Re and Os content and isotope ratio data of international standard samples of three lithology rock samples

[0097]

[0098]

[0099] Table 4 PGE content data of international standard samples of three lithology rock samples

[0100]

[0101] The rock sample platinum group element separation, enrichment and high-precision determination method of the disclosed embodiment removes matrix elements and most interfering elements through a cationic resin column, and then removes the remaining small part of interfering elements in a targeted manner through an LN resin column, thereby improving the separation and enrichment efficiency of platinum group elements; the upper column samples loaded on the cationic resin column and the LN resin column need to be redissolved in 0.1 mol / L HCl, and 0.1 mol / L HCl is used for leaching, which can better remove elements sensitive to HCl concentration, improve the removal rate of matrix elements and interfering elements and the types of interfering elements, and improve the accuracy and precision of platinum group element testing; the platinum group elements in the rock sample are separated and enriched by combining the cationic resin column and the LN resin column, which has a longer service life, a simple operation process, a higher recovery rate of platinum group elements, and a higher removal rate of matrix elements and interfering elements, and provides a new solution for the high-precision determination of platinum group elements in rock samples; the Re-Os content and isotope data of rock geological samples of the same component and the content of other platinum group elements can be obtained simultaneously by using the same chemical process, saving testing time.

[0102] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the embodiments of the present disclosure, but the embodiments of the present disclosure are not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the embodiments of the present disclosure.

Claims

1. A method for separation and enrichment of platinum group elements in rock samples and high-precision determination thereof, characterized in that: The method comprises: Step 1: Select and weigh a rock geological sample, add the weighed sample into a mixed diluent for dissolution, and obtain a platinum group element solution; Step 2, directly distilling the platinum group element solution to separate Os, and obtaining an Os absorption solution and a distillation residue solution, respectively, wherein the distillation residue solution includes Re and other platinum group elements; Step 3, the distillation residual liquid is sequentially subjected to acid removal, medium conversion, and acidity reduction, and then redissolved in 0.1 mol / L HCl to obtain a sample solution; Step 4: Load the sample solution into a cationic resin column, and use 0.1 mol / L HCl for elution, so that the matrix elements and some interfering elements are adsorbed on the cationic resin column, and Re and other platinum group elements and remaining interfering elements are eluted into the elution liquid; Step 5, the filtrate is redissolved in 0.1 mol / L HCl and then loaded into a LN resin column, and leached and eluted with 0.1 mol / L HCl so that the remaining interfering elements are adsorbed in the LN resin column to obtain a solution containing Re and other platinum group elements; Step 6: High-precision determination of Os is performed using the Os absorption solution, and high-precision determination of Re and other platinum group elements are performed using the solutions containing Re and other platinum group elements, respectively.

2. The method according to claim 1, characterized in that In step 4, the sample solution is loaded into a cationic resin column for elution, comprising: Filling 10 mL of AG50W-X8 resin into an empty column to obtain the cationic resin column, and sequentially performing column cleaning and column balancing on the cationic resin column; Loading the sample solution dissolved in 0.1 mol / L HCl onto the cationic resin column for sample loading; Slowly add 20 mL of 0.1 mol / L HCl to the cationic resin column for leaching and elution, so that the matrix elements and some interfering elements are adsorbed on the cationic resin, and Re and other platinum group elements and remaining interfering elements are leached into the filtrate.

3. The method according to claim 1, characterized in that In step 5, the filtrate is redissolved in 0.1 mol / L HCl and then loaded into a LN resin column for leaching and elution, comprising: The filtrate was concentrated to 100 μL to 120 μL at 190° C. to 200° C. on a hot plate, and 2 ml of 0.1 mol / L HCl was added for redissolution; Adding 0.55 g to 0.60 g of LN resin into an empty column to obtain an LN resin column, and sequentially performing column washing and column balancing on the LN resin column; The reconstituted filtrate is loaded onto the LN resin column for sample loading; 4 mL of 0.1 mol / L HCl was slowly added to the LN resin column for leaching, so that the remaining interfering elements were adsorbed on the LN resin column to obtain a solution containing Re and other platinum group elements.

4. The method according to claim 1, characterized in that: In step 3, the distillation residual liquid is sequentially subjected to acid removal, medium conversion, and acidity reduction, and then redissolved in 0.1 mol / L HCl to obtain a sample solution, including: The residual solution from the distillation was evaporated to dryness on a hot plate at 190°C to 200°C; Add 1ml 6mol / L HCl and heat until almost dry, repeat 2-3 times to drive away HNO3; Add 1 ml of 0.1 mol / L HCl and heat until almost dry, repeat 2 to 3 times to reduce the acidity of the distillation residue; After adding 1 ml of 1 mol / L HCl for re-dissolution, the mixture was diluted to 10 ml to obtain the sample solution.

5. The method according to any one of claims 1 to 3, characterized in that: In step 1, a rock geological sample is selected and weighed, and the weighed sample is added into a mixed diluent for dissolution to obtain a platinum group element solution, including: Accurately weigh 0.5 g to 1 g of a rock geological sample and add the sample into a Carius tube; Accurate weighing 185 Re- 190 Os and 191 Ir- 99 Ru- 105 Pd- 198 Pt mixed diluent, adding the mixed diluent and sample dissolving reagent under the freezing condition of Carius tube; The Cairus tube was sealed by melting and covered with a stainless steel sleeve, and placed in an oven, heated at 220° C. for 12 hours, then at 230° C. for 12 hours, and then cooled to room temperature.

6. The method according to claim 5, characterized in that In step 2, the platinum group element solution is directly distilled to separate Os, and Os absorption solution and distillation residual solution are obtained respectively, including: The Cairus tube is opened with an acetylene flame under freezing conditions, and after returning to room temperature, Os is separated by direct distillation technology, Re and other platinum group elements are retained in the residual distillation solution, and Os is retained in a 1:1 HBr:H2O distillation absorption liquid to obtain an Os absorption liquid.

7. The method according to claim 1, characterized in that In step 6, the Os absorption solution is used to perform high-precision determination of Os, including: Micro-distillation technology was used to enrich and purify Os and concentrate the sample; The concentrated sample was spotted on a high-purity Pt tape, and thermal surface ionization mass spectrometry was used to measure Os with high precision.

8. The method according to claim 1, characterized in that In step 6, the high-precision determination of Re and other platinum group elements is performed respectively by using the solution containing Re and other platinum group elements, including: The above solution containing Re and other platinum group elements is evaporated to 1 mL to 2 mL, and 5 ml of 5% HNO3 is added to obtain a sample to be measured; Using a multi-collector plasma mass spectrometer to perform high-precision determination of Re in the sample to be determined; Tandem quadrupole plasma mass spectrometry is used to perform high-precision determination of other platinum group elements in the sample to be determined.

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