Method for separating and enriching platinum group elements in rock sample and high-precision determination method thereof

Abstract

The embodiment of the present disclosure provides a rock sample platinum group element separation and enrichment and high-precision determination method, which comprises the following steps: weighing a rock geological sample and dissolving the sample to obtain a platinum group element dissolution solution; directly distilling the platinum group element dissolution solution to separate Os, and respectively obtaining an Os absorption solution and a distillation residual solution containing Re and other platinum group elements; resolubilizing the distillation residual solution in 0.1 mol / L HCl to obtain a sample solution; adding the sample solution into a cation resin column, and eluting and stripping the matrix elements, Re and other platinum group elements by using 0.1 mol / L HCl; resolubilizing the elution liquid in 0.1 mol / L HCl and adding the elution liquid into an LN resin column, eluting and stripping the 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. The method is simple in operation, high in platinum group element recovery rate, and high in removal rate of matrix elements and interference elements.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure belongs to the technical field of geological rock analysis, and particularly relates to a method for separating and enriching platinum group elements of a rock sample and high-precision determination thereof. BACKGROUND

[0002] The platinum group elements include six noble metal elements of osmium (Os), iridium (Ir), ruthenium (Ru), rhodium (Rh), platinum (Pt), and palladium (Pd). The highly ironophilic and sulfurophilic properties of PGEs make them mainly enriched in the core and a small amount distributed in the mantle, and among the platinum group elements, Os is related to two radioisotope systems, namely 187 Re- 187 Os isotope system and 190 Pt- 186 Os isotope system. Therefore, the differentiation behavior of platinum group elements in the process of crust-mantle evolution also becomes 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 of earth sciences and major needs, but the content of platinum group elements in most geological samples is very low, often only pg-ng level, far lower than the detection line of general analysis methods. Therefore, the preferred sample dissolution method for obtaining high-precision platinum group element data is the Cairus tube closed dissolution method with ultra-low process blank. Under the closed dissolution conditions of Carius, combined with the isotope dilution method, high-precision platinum group elements and Re-Os can be simultaneously determined, which is not only friendly to precious samples and reduces the chemical process, but also represents the isotopic composition characteristics of the same sample for the simultaneous analysis of Re-Os and platinum group elements.

[0003] In the existing research on the separation and enrichment method of platinum group elements, after the rock sample is dissolved by 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 recovery rate of Os can reach more than 80%. For other platinum group elements, ion exchange separation and enrichment is currently used. For example, in some separation methods, after alkaline dissolution or Carius tube dissolution, Te-coprecipitation method is used to enrich platinum group elements, and then cation exchange and P507 resin are used to separate platinum group. In another separation method, after Carius tube dissolution, most of the matrix elements are removed by using cation exchange resin, and then the tantalum reagent is adsorbed and loaded on the macroporous resin material Amberchrom CG-71 to form a BPHA resin column, and Zr, Hf, Ta, W and other interference elements are further removed. In another separation method, a method is established in which palladium reacts with chloride ions to form a complex in hydrochloric acid medium, and the complex can be adsorbed by macroporous weak basic styrene anion exchange resin. In another separation method, after Carius tube dissolution, CCl4 extraction is used to separate Os, Re and the rest of the platinum group elements, and anion resin is used to separate and enrich Re and platinum group elements under different concentration and multiple acid medium system leaching conditions.

[0004] However, the existing separation and enrichment method of platinum group elements has the following problems:

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

[0006] 2) Only using cation resin to separate and enrich platinum group elements in rock samples can adsorb a large amount of matrix elements such as Fe, Cu, Ni, Zn, etc., but the adsorption effect of Zr, Hf, Ta, W and other interference elements is poor, which increases the isotope interference in plasma mass spectrometry and reduces the accuracy and precision of platinum group element testing.

[0007] 3) When cation resin is combined with BPHA resin to separate and enrich platinum group elements, BPHA resin needs to be prepared in advance, and needs to be supplemented after each use, and the preparation process is complex, the service life is short, and the platinum group element analysis time and process are greatly increased.

[0008] In view of the above problems, it is necessary to propose a rock sample platinum group element separation and enrichment and high-precision determination method which is reasonable in design and effectively solves the above problems. SUMMARY

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

[0010] The method comprises the following steps:

[0011] Step one, selecting and weighing a rock geological sample, adding the weighed sample into a mixed diluent for sample dissolution to obtain a platinum group element dissolution solution;

[0012] Step two, directly distilling the platinum group element dissolution solution to separate Os to obtain an Os absorption solution and a distillation residual solution, wherein the distillation residual solution comprises Re and other platinum group elements;

[0013] Step three, sequentially performing acid removal, medium conversion and acidity reduction on the distillation residual solution, and then redissolving the distillation residual solution in 0.1 mol / L HCl to obtain a sample solution;

[0014] Step four, loading the sample solution into a cation resin column, and performing elution and washing by using 0.1 mol / L HCl, so that matrix elements and part of interference elements are adsorbed on the cation resin column, and Re and other platinum group elements and residual interference elements are eluted into an elution solution;

[0015] Step five, redissolving the elution solution in 0.1 mol / L HCl, and loading the elution solution into an LN resin column, and performing elution and washing by using 0.1 mol / L HCl, so that residual interference elements are adsorbed on the LN resin column to obtain a solution containing Re and other platinum group elements;

[0016] Step six, performing high-precision determination on Os by using the Os absorption solution, and performing high-precision determination on Re and other platinum group elements by using the solution containing Re and other platinum group elements.

[0017] Optionally, the loading of the sample solution into the cation resin column for elution and washing in step four comprises the following steps:

[0018] 10 mL of AG50W-X8 resin is filled in an empty column to obtain the cation resin column, and the cation resin column is sequentially subjected to column cleaning and column balancing;

[0019] The sample solution dissolved in 0.1 mol / L HCl is loaded on the cation resin column;

[0020] 20 mL of 0.1 mol / L HCl is slowly added to the cation resin column for elution and washing, so that matrix elements and part of interference elements are adsorbed on the cation resin, and Re and other platinum group elements and residual interference elements are eluted into an elution solution.

[0021] Optionally, the leaching solution in step five is redissolved in 0.1 mol / L HCl and then loaded into the LN resin column for leaching and elution, including:

[0022] The leaching solution is concentrated to 100 μL-120 μL on an electric hot plate at 190-200°C, and 2 ml of 0.1 mol / L HCl is added for redissolution;

[0023] 0.55-0.60 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 cleaning and column balancing;

[0024] The redissolved leaching solution is loaded into the LN resin column for sample loading;

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

[0026] Optionally, the distillation residue in step three is sequentially subjected to acid removal, medium transfer, and acidity reduction, and then redissolved in 0.1 mol / L HCl to obtain a sample solution, including:

[0027] The distillation residue is acid removed and evaporated to dryness on an electric hot plate at 190-200°C;

[0028] 1 ml of 6 mol / L HCl is added and heated to near dryness, and the process is repeated 2-3 times to remove HNO3;

[0029] 1 ml of 0.1 mol / L HCl is added and heated to near dryness, and the process is repeated 2-3 times to reduce the acidity of the distillation residue;

[0030] After redissolving with 1 ml of 1 mol / L HCl, dilution to 10 ml is performed to obtain the sample solution.

[0031] Optionally, in step one, a rock-type geological sample is selected and weighed, and the weighed sample is added to a mixed diluent for sample dissolution to obtain a platinum group element solution, including:

[0032] 0.5-1 g of a rock-type geological sample is accurately weighed and added to a Carius tube;

[0033] 0.5-1 g of a rock-type 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, and the mixed diluent and sample dissolution reagent are added under Carius tube refrigeration conditions;

[0034] The Cairus tube orifice is closed by burning and sealing, a stainless steel sleeve is wrapped around the tube and placed in an oven at 220°C for 12 hours and then at 230°C for 12 hours before cooling to room temperature.

[0035] Optionally, the platinum group element solution in step two is directly distilled to separate Os, obtaining an Os absorption solution and a distillation residual solution, including:

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

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

[0038] Micro-distillation technology is used to enrich and purify Os, and the sample is concentrated;

[0039] The concentrated sample is spotted on a high-purity Pt strip, and high-precision determination of Os is performed using thermal surface ionization mass spectrometry.

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

[0041] The Re and other platinum group element-containing solution is evaporated to 1mL-2mL, and 5ml

[0042] 5% HNO3 is added to obtain a sample to be determined;

[0043] High-precision determination of Re in the sample to be determined is performed using multi-receiving plasma mass spectrometry;

[0044] High-precision determination of other platinum group elements in the sample to be determined is performed using tandem quadrupole plasma mass spectrometry.

[0045] The rock sample platinum group element separation and enrichment and high-precision determination method of the embodiment of the present disclosure removes matrix elements and most of interfering elements through a cation resin column, and improves the separation and enrichment efficiency of platinum group elements by removing the remaining small part of interfering elements through an LN resin column; the sample loaded on the cation resin column and the LN resin column both need to be redissolved in 0.1 mol / L HCl, and both are eluted with 0.1 mol / L HCl, 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 combination of the cation resin column and the LN resin column is used to separate and enrich platinum group elements in rock samples, which has a longer service life, a simple operation process, a higher platinum group element recovery rate, a higher matrix element and interfering element removal rate, and provides a new solution for high-precision determination of platinum group elements in rock samples; the same chemical process can be used to obtain Re-Os content and isotope data and other platinum group element contents of the same component rock sample at the same time, saving testing time. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a flowchart of a rock sample platinum group element separation and enrichment and high-precision determination method in an embodiment of the present disclosure;

[0047] Figure 2 is a Re and other platinum group element elution curve diagram of 10 ml cation resin under 0.1 mol / L HCl elution conditions in another embodiment of the present disclosure;

[0048] Figure 3 is a Re and other platinum group element elution curve diagram of LN resin under 0.1 mol / L HCl elution conditions in another embodiment of the present disclosure;

[0049] Figure 4 is a measurement count diagram of interfering elements after passing through the LN resin column under 0.1 mol / L HCl elution conditions in another embodiment of the present disclosure. DETAILED DESCRIPTION

[0050] In order for 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 with reference to the drawings and specific embodiments.

[0051] The present disclosure provides a rock sample platinum group element separation and enrichment and high-precision determination method, which comprises the following steps:

[0052] Step one, select and weigh a rock geological sample, add the weighed sample to a mixed diluent for sample dissolution to obtain a platinum group element solution.

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

[0054] The Carius tube is frozen in liquid nitrogen-alcohol mixture, and the mixed diluent is transferred into the Carius tube by using 2.5ml of sub-boiling purified HCl under the condition of Carius tube freezing, and 5ml of sub-boiling purified HNO3 and H2O2 is added after freezing.

[0055] After freezing, the tube opening of the Carius tube is sealed by burning, and is sleeved with a stainless steel sleeve and placed in an oven, heated at 220°C for 12 hours, and then heated at 230°C for 12 hours, and then cooled to room temperature.

[0056] Step two, the platinum group element solution is directly distilled to separate Os, and Os absorption solution and distillation residual solution are obtained, wherein the distillation residual solution contains Re and other platinum group elements.

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

[0058] H2O distillation absorption solution, and Os absorption solution is obtained.

[0059] Step three, the distillation residual solution is sequentially subjected to acid chasing, medium transfer, and acidity reduction, and then is redissolved in 0.1mol / L HCl to obtain a sample solution.

[0060] Specifically, the distillation residual solution is evaporated to dryness by acid chasing at 190°C-200°C on an electric hot plate. Preferably, in the present embodiment, the distillation residual solution is evaporated to dryness by acid chasing at 190°C.

[0061] 1ml of 6mol / L HCl is added and heated to near dryness, and the operation is repeated 2-3 times to remove HNO3. Preferably, in the present embodiment, the operation is repeated 2 times to remove HNO3.

[0062] 1ml of 0.1mol / L HCl is added and heated to near dryness, and the operation is repeated 2-3 times to reduce the acidity of the distillation residual solution. Preferably, in the present embodiment, the operation is repeated 2 times to reduce the acidity of the distillation residual solution.

[0063] After adding 1 ml of 1 mol / L HCl for reconstitution, dilute to 10 ml, that is, reconstitute the distillation residue in 0.1 mol / L HCl to obtain the sample solution.

[0064] Step four, load the sample solution into the cation resin column, and elute with 0.1 mol / L HCl to adsorb the matrix elements and part of the interference elements on the cation resin column, and elute Re and other platinum group elements and the remaining interference elements into the eluate.

[0065] First, fill 10 mL of AG50W-X8 resin into an empty column to obtain the cation resin column, and sequentially perform column cleaning and column balancing on the cation resin column.

[0066] Specifically, the empty column is a Bio-Rad Econo-Pac chromatography empty column (14 cm high, 1.5*12 cm polypropylene column), and the particle size of the AG50W-X8 resin is 50-100 mesh.

[0067] After the AG50W-X8 cation resin column is cleaned with deionized water, wash with 60 ml of 6 mol / L HCl, 30 ml of deionized water, and 30 ml of 0.1 mol / L HCl.

[0068] Second, load the sample solution dissolved in 0.1 mol / L HCl into the cation resin column for sample loading.

[0069] Third, slowly add 20 mL of 0.1 mol / L HCl to the cation resin column for elution to adsorb the matrix elements and part of the interference elements on the cation resin, and elute Re and other platinum group elements and the remaining small amount of interference elements into the eluate.

[0070] Specifically, as shown in Figure 2 Slowly add 20 mL of 0.1 mol / L HCl to the cation resin column for elution, wherein the matrix elements Li, Be, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, etc. are adsorbed on the AG50W-X8 cation resin, and most of the interference elements Cd, Mo, Hf, Zr, W, Ta, etc. are adsorbed on the AG50W-X8 cation resin, and Re and other platinum group elements and the remaining small amount of interference elements are eluted into the eluate for further processing. Among them, Cd is very sensitive to the acidity of the cation resin, and Cd is mainly adsorbed by the cation resin, which can be basically removed by the cation resin.

[0071] In the cation resin leaching strip, 10 ml of cation resin is filled in the Econo-Pac chromatography empty column, and leaching is performed under the condition of 0.1 mol / L HCl, and the recovery rates of Re and other platinum group elements obtained are all greater than 91% (as shown in Table 1), and meanwhile, the removal rates of each matrix element are greater than 96% (as shown in Table 2) under this condition.

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

[0073]

[0074] Table 2 Removal rates of trace elements under different HCl leaching conditions

[0075]

[0076]

[0077] In the present embodiment, the matrix elements and most of the interference elements are removed by the cation resin column, the sample loaded on the cation resin column is redissolved in 0.1 mol / L HCl, and 20 mL of 0.1 mol / L HCl is added to the cation resin column for leaching and elution, which can better remove the elements sensitive to HCl concentration. For example, Li, Nb, Mo, Cd, Sn, W, Pb and Bi are all relatively sensitive to HCl acidity, and their removal rates will decrease when the HCl concentration is high, among which, Cd and Mo have a great interference on the PGE mass spectrum measurement, and it is necessary to ensure the removal of elements sensitive to HCl acidity. Therefore, in the present embodiment, 20 mL of 0.1 mol / L HCl is used for leaching and elution of the cation resin column, so as to improve the removal rates of matrix elements and interference elements and the types of interference elements, and improve the testing accuracy and precision of platinum group elements.

[0078] Step five, the leaching solution is redissolved in 0.1 mol / L HCl and loaded in the LN resin column, and leaching and elution are performed by using 0.1 mol / L HCl, so that the remaining interference elements are adsorbed on the LN resin column, and a solution containing Re and other platinum group elements is obtained.

[0079] Firstly, the leaching solution is concentrated to 100 μL-120 μL on the electric hot plate at 190-200 ℃, and 2 mL of 0.1 mol / L HCl is added for redissolution. Preferably, in the present embodiment, the leaching solution is concentrated to 100 μL on the electric hot plate at 190 ℃.

[0080] Secondly, 0.55-0.60 g of LN resin is added to the empty column to obtain the LN resin column, and the LN resin column is sequentially subjected to column cleaning and column balancing.

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

[0082] Again, the eluate after re-dissolution is loaded into the LN resin column for sample column loading.

[0083] Then, 4 mL of 0.1 mol / L HCl is slowly added into the LN resin column for elution, so that the remaining small amount of interference elements are adsorbed in the LN resin column, and a solution containing Re and other platinum group elements is obtained.

[0084] Specifically, as shown in Figure 3 4 mL of 0.1 mol / L HCl is slowly added into the LN resin column for elution, and the five interference elements Zr, Mo, Hf, Ta and W are adsorbed on the LN resin, and the solution containing Re and other platinum group elements flows out with the eluate and is collected for further processing. As shown in Figure 4 The measurement counts of the five interference elements in the eluate after loading 1000 ng of mixed standard solution containing Zr, Mo, Hf, Ta and W on the LN resin are shown in the table. The removal rates of the five elements are all greater than 98%.

[0085] In this embodiment, after the matrix elements and most of the interference elements are removed by the cation resin column, the remaining small amount of interference elements are removed by the LN resin column, which improves the separation and enrichment efficiency of the platinum group elements; the sample loaded on the LN resin column is re-dissolved in 0.1 mol / L HCl, and 4 mL of 0.1 mol / L HCl is added into the LN resin column for elution, which can better remove the remaining other interference elements sensitive to the concentration of HCl, further improve the removal rates of the matrix elements and the interference elements and the types of the interference elements, and improve the testing accuracy and precision of the platinum group elements.

[0086] Step six, high-precision determination of Os by the Os absorption liquid, and high-precision determination of Re and other platinum group elements by the solution containing Re and other platinum group elements.

[0087] In step six, the high-precision determination of Os by the Os absorption liquid includes:

[0088] First, the micro-distillation technology is used to enrich and purify Os, and the sample is concentrated.

[0089] Specifically, the Os distillation absorption liquid is transferred into a 150 ml Teflon bowl, heated on an electric hot plate at 150°C until about 50 μL remains and is transferred onto a Teflon sharp bottom bottle cap, evaporated dry on an electric hot plate at 120°C, covered with 50 μL of the distillation purified H2SO4-CrO3 mixed solution, 4 times of purified HBr is added as the Os absorption liquid in the sharp bottom part of the bottle, the sharp bottom part is inverted on the cap and tightened, wrapped with aluminum foil, and placed on the electric hot plate for 4 hours at 80°C. After cooling to room temperature, the H2SO4-CrO3 on the cap is discarded, the sharp bottom bottle is righted, the cap is tightened, and the bottle is placed in an oven for 2 hours at 80°C,

[0090] Secondly, the concentrated sample is spotted on a high purity Pt strip, and high precision determination of Os is performed using thermal surface ionization mass spectrometry.

[0091] In step six, high precision determination of Re and other platinum group elements is performed on the Re and other platinum group element-containing solution, including:

[0092] The Re and other platinum group element-containing solution is evaporated to 1 mL-2 mL, and 5 ml of 5% HNO3 is added to obtain a sample to be determined. High precision determination of Re in the sample to be determined is performed using multi-receiving plasma mass spectrometry. High precision determination of other platinum group elements in the sample to be determined is performed using tandem quadrupole plasma mass spectrometry.

[0093] It should be noted that during the mass spectrometry measurement, the determination 90 Zr + , 95 Mo + , 111 Cd + , 178 Hf + , 202 Hg + is performed to monitor the interference of 90 ZrO + and 106 Cd + on 106 Pd + , 108 Cd + on 108 Pd + , 92 MoO + on 108 Pd + , 177,178,180 HfO + on 193 Ir + , 194 Pt + , 196 Pt+ Interference, 198 Hg + right 198 Pt + Interference. Measurement 99 Ru、 101 Ru、 102 Ru、 105 Pd, 106 Pd, 108 Pd, 191 Ir、 193 Ir、 195 Pt, 198 The count and isotope ratios of Pt. When subtracting interferences, in addition to the interference from oxides of interfering elements on PGE, the following must be subtracted: 105 Pd pairs 102 Interference from Ru was investigated. Before measurement, mixed PGE standard solution, mixed standard solution of interfering elements, and matrix element standard solution were measured to detect instrument mass bias effect, isotope ratio fractionation correction, and oxide yield correction of interfering elements. Background signal was monitored by measuring 2% v / v HNO3 solution.

[0094] The following examples illustrate the method for separating and enriching platinum group elements in rock samples and their high-precision determination in accordance with the embodiments of this disclosure.

[0095] Using the platinum group element (PGE) separation and enrichment method and its high-precision determination method for rock samples according to embodiments of this disclosure, Re-Os isotope and PGE contents were analyzed for three international standards of rock types: BHVO-2 (basalt), TDB-1 (diabase), and UMT-1 (ultramafic rock). The Re-Os isotope data for the three international standards are shown in Table 3. The Re and Os contents and isotope ratios are consistent with the recommended values ​​within the error range. The PGE isotope data for the three international standards are shown in Table 4. The Pt, Pd, Ru, and Ir contents are consistent with the recommended values ​​within the error range.

[0096] Table 3. Re and Os contents and isotopic ratios of international standard samples from three types of rock.

[0097]

[0098]

[0099] Table 4. PGE content data of international standard samples from three types of rock.

[0100]

[0101] The rock sample platinum group element separation and enrichment and high-precision determination method of the embodiments of the present disclosure removes matrix elements and most of interfering elements through a cation resin column, and removes the remaining small part of interfering elements through an LN resin column, thereby improving the separation and enrichment efficiency of platinum group elements; the sample loaded on the cation resin column and the LN resin column both need to be redissolved in 0.1 mol / L HCl, and both are eluted with 0.1 mol / L HCl, 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 use of a combination of a cation resin column and an LN resin column to separate and enrich platinum group elements in rock samples has a longer service life, a simple operation process, a higher platinum group element recovery rate, a higher matrix element and interfering element removal rate, and provides a new solution for high-precision determination of platinum group elements in rock samples; the same chemical process can be used to simultaneously obtain Re-Os content and isotope data and other platinum group element content of the same component rock geological sample, thereby saving testing time.

[0102] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the embodiments of the present disclosure, and the embodiments of the present disclosure are not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also considered within the protection scope of the embodiments of the present disclosure.

Claims

1. A method for the separation and enrichment of platinum group elements from a rock sample and their high-precision determination, characterized in that, The method comprises: Step one, selecting and weighing a rock geological sample, adding the weighed sample into a mixed diluent for sample dissolution to obtain a platinum group element solution; Step two, directly distilling the platinum group element solution to separate Os to obtain an Os absorption solution and a distillation residual solution, wherein the distillation residual solution comprises Re and other platinum group elements; Step three, sequentially performing acid removal, medium conversion and acidity reduction on the distillation residual solution, and then resolubilizing in 0.1 mol / L HCl to obtain a sample solution, specifically comprising: performing acid removal and dry evaporation on the distillation residual solution on an electric hot plate at 190-200 DEG C; adding 1 mL of 6 mol / L HCl and heating to near dryness, repeating 2-3 times to remove HNO3; adding 1 mL of 0.1 mol / L HCl and heating to near dryness, repeating 2-3 times to reduce the acidity of the distillation residual solution; after adding 1 mL of 1 mol / L HCl for resolubilization, diluting to 10 mL to obtain the sample solution; Step four, loading the sample solution into a 10 mL cation resin column, and performing elution and washing with 20 mL of 0.1 mol / L HCl, so that the matrix elements and part of the interference elements are adsorbed on the cation resin column, and Re and other platinum group elements and the remaining interference elements are eluted into an eluate, wherein the recovery rate of Re and other platinum group elements is greater than 91%, and the removal rate of each matrix element is greater than 96%; Step five, resolubilizing the eluate in 0.1 mol / L HCl and loading it into an LN resin column, and performing elution and washing with 4 mL of 0.1 mol / L HCl, so that the remaining interference elements are adsorbed on the LN resin column to obtain a Re and other platinum group element-containing solution, wherein the removal rate of Zr, Mo, Hf, Ta and W is greater than 98%; wherein the sample loaded on the cation resin column and the LN resin column needs to be resolubilized in 0.1 mol / L HCl, and 0.1 mol / L HCl is used for elution, so as to better remove elements sensitive to HCl concentration; Step six, high-precision determination of Os through the Os absorption solution, and high-precision determination of Re and other platinum group elements through the Re and other platinum group element-containing solution.

2. The method of claim 1, wherein, In step four, the sample solution is loaded into a cation resin column for elution and washing, comprising: 10 mL of AG50W-X8 resin is filled into an empty column to obtain the cation resin column, and the cation resin column is sequentially subjected to column cleaning and column balancing; The sample solution dissolved in 0.1 mol / L HCl is loaded into the cation resin column for sample column loading; 20 mL of 0.1 mol / L HCl is slowly added to the cation resin column for elution and washing, so that the matrix elements and part of the interference elements are adsorbed on the cation resin, and Re and other platinum group elements and the remaining interference elements are eluted into an eluate.

3. The method of claim 1, wherein, In step five, the eluate is resolubilized in 0.1 mol / L HCl and loaded into an LN resin column for elution and washing, comprising: The leaching solution is concentrated to 100-120 μL on an electric hot plate at 190-200 ℃, and 2 ml of 0.1 mol / L HCl is added for reconstitution; 0.55-0.60 g of LN resin is added to an empty column to obtain an LN resin column, and the LN resin column is sequentially subjected to column cleaning and column balancing; The reconstituted leaching solution is loaded on the LN resin column for sample column loading; 4 mL of 0.1 mol / L HCl is slowly added to the LN resin column for leaching, so that the remaining interfering elements are adsorbed on the LN resin column, and a solution containing Re and other platinum group elements is obtained.

4. The method according to any one of claims 1 to 3, characterized in that, In step one, a rock-type geological sample is selected and weighed, and the weighed sample is added to a mixed diluent for sample dissolution, to obtain a platinum group element solution, which includes: 0.5-1 g of a rock-type geological sample is accurately weighed and added to a Carius tube; accurately weighed 185 Re- 190 Os and 191 Ir- 99 Ru- 105 Pd- 198 Pt mixed diluent, said mixed diluent and sample dissolution reagent being added under Carius tube refrigeration conditions; The Carius tube is sealed by burning the mouth, wrapped with a stainless steel sleeve, and placed in an oven for heating at 220 ℃ for 12 hours and at 230 ℃ for 12 hours, and then cooled to room temperature.

5. The method of claim 4, wherein, In step two, the platinum group element solution is directly distilled to separate Os, to obtain an Os absorption solution and a distillation residual solution, which includes: The Carius tube is opened by using an acetylene flame under cold conditions, and after recovering to room temperature, Os is separated by using a direct distillation technique, Re and other platinum group elements are retained in the distillation residual solution, and Os is retained in a 1:1 HBr:H2O distillation absorption solution, to obtain an Os absorption solution.

6. The method of claim 1, wherein, In step six, high-precision determination of Os is performed by using the Os absorption solution, which includes: A micro-distillation technique is used to enrich and purify Os, and the sample is concentrated; The concentrated sample is spotted on a high-purity Pt strip, and high-precision determination of Os is performed by using thermal surface ionization mass spectrometry.

7. The method of claim 1, wherein, In step six, high-precision determination of Re and other platinum group elements is performed by using the solution containing Re and other platinum group elements, which includes: The above solution containing Re and other platinum group elements is evaporated to 1-2 mL, and 5 mL of 5% HNO3 is added, to obtain a sample to be determined; A multi-receiving inductively coupled plasma mass spectrometer is used to perform high-precision determination of Re in the sample to be determined; A tandem quadrupole inductively coupled plasma mass spectrometer is used to perform high-precision determination of other platinum group elements in the sample to be determined.

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