Olivine product for capturing supercritical fluid and preparation and application method thereof

Abstract

The invention discloses an olivine product for capturing supercritical fluid and a preparation and application method of the olivine product. The preparation method of the olivine product comprises the following steps: cutting natural olivine which does not contain fluid and melt inclusions into olivine particles along a C axis, then soaking the olivine particles in 30-40wt% of hydrofluoric acid until cracks represented by the particles form a network shape, and then cleaning and drying the olivine particles to obtain the olivine product. The olivine product provided by the invention can effectively capture and store supercritical fluid in a high-temperature and high-pressure experiment, and samples for analysis, which are suitable for various analysis methods such as Raman spectroscopy, LA-ICPMS and the like, are obtained.

Description

Technical Field

[0001] The invention relates to the technical field of fluid inclusions, and in particular to an olivine product for capturing supercritical fluids and a preparation method thereof. Background Art

[0002] The fluid produced in the high temperature and high pressure experiment is difficult to form glass when quenched, so it is necessary to use minerals with internal cracks to capture it and form fluid inclusions for further processing such as component analysis. The main method for preparing such minerals in the prior art is to heat and then quench the quartz particles or to manually cut and etch them to produce cracks, and then use the quartz particles with cracks to capture the fluid produced in the experiment. However, quartz will transform into coesite under the high temperature and high pressure conditions that produce supercritical fluids, which is not suitable for use in the capture of supercritical fluids. In addition, the fluid inclusions formed by the mineral particles obtained by the method of heating first and then quenching are usually small (<20μm), which is not conducive to the analysis of the inclusion composition by micro-area analysis equipment such as LA-ICPMS with a large beam spot. Summary of the invention

[0003] In view of the defects of the prior art, the purpose of the present invention is to provide a new olivine product for capturing supercritical fluids and a preparation and application method thereof. The olivine product can capture supercritical fluids in high temperature and high pressure experiments, and the obtained fluid inclusions are suitable for accurate analysis of supercritical fluids by micro-area analysis equipment such as Raman spectroscopy analysis and LA-ICPMS.

[0004] The present invention first provides the following technical solution:

[0005] A method for preparing an olivine product for capturing a supercritical fluid, comprising:

[0006] (1) natural olivine without fluid and melt inclusions is cut along its C-axis direction, using a rough-surfaced cutter to form natural cracks on the surface of the olivine particles obtained after cutting;

[0007] (2) immersing the olivine particles in hydrofluoric acid having a mass concentration of 30-40 wt.% until the cracks on the particles are connected to form a network, thereby obtaining etched particles;

[0008] (3) Cleaning and drying the etched particles to obtain the olivine product for capturing supercritical fluid.

[0009] The above preparation method of the present invention selects olivine crystals without melt and / or fluid inclusions as the preparation raw material, which can effectively avoid the interference of inclusions already existing in the olivine on the analysis results. At the same time, the olivine will not undergo phase change under the high temperature and high pressure conditions generated by the supercritical fluid, which is conducive to the retention of the supercritical fluid. In addition, the inventor unexpectedly found that olivine will produce separated cracks during cutting. After these cracks are etched with a certain concentration of hydrofluoric acid, they will be interconnected into a network. After being applied to supercritical fluid capture, fluid inclusions with a diameter of more than tens of microns can be formed, which is convenient for LA-ICPMS and other equipment with a large beam spot (diameter>20μm) to perform analysis and testing.

[0010] Preferably, the size of the olivine particles is determined by a sample chamber required for obtaining a high temperature and high pressure experiment of a supercritical fluid.

[0011] Preferably, the size of the olivine particles is 1.5 mm×2.5 mm×1.5 mm.

[0012] Preferably, ultrapure water is used for the cleaning, and the temperature of the drying is 110°C.

[0013] The present invention further provides an olivine product prepared according to the preparation method and used for capturing supercritical fluid.

[0014] The surface of the olivine product obtained by the present invention is evenly distributed with cracks interconnected into a network and having a width of less than 100 μm, which can successfully capture supercritical fluid in high temperature and high pressure experiments and preserve it by forming fluid inclusions. The fluid inclusions have a stable structure, clear boundaries, no obvious impurities, and are large in size (>20 μm), making them suitable for a variety of analytical methods.

[0015] The present invention further provides an application method of the above olivine product, which comprises:

[0016] (1) placing the olivine product into the bottom of a tubular metal sample chamber with one end closed, adding experimental raw materials for obtaining a supercritical fluid into the tubular metal sample chamber, and then closing the other end of the tubular metal sample chamber to obtain a closed sample chamber;

[0017] (2) placing the closed sample chamber into an experimental device for obtaining a supercritical fluid, and performing a reaction under high temperature and high pressure;

[0018] (3) After the reaction is completed, the mixture is quenched and the closed sample chamber is taken out to obtain an analysis sample containing supercritical fluid inclusions.

[0019] In the above application method of the present invention, when the temperature and pressure required for the formation of supercritical fluid are generated in the high-temperature and high-pressure reaction, the supercritical fluid appears in the sample chamber and enters the olivine particles through the cracks to form fluid inclusions. When the reaction is completed and quenched, the sample chamber is taken out and made into a resin target for analysis. After polishing to expose the particles, the composition, properties, etc. of the fluid in the fluid inclusions can be analyzed.

[0020] Preferably, step (1) specifically comprises:

[0021] The olivine product is placed at the bottom of a first tubular metal sample bin with one end closed, and then experimental raw materials for obtaining supercritical fluid are added to the first tubular metal sample bin, and then the other end of the first tubular metal sample bin is closed to obtain a closed inner bin; the closed inner bin is placed at the bottom of a second tubular metal sample bin with one end closed, and then oxygen fugacity buffer raw materials are added to the second tubular metal sample bin, and then the other end of the second tubular metal sample bin is closed to obtain the closed sample bin.

[0022] Preferably, the material of the first tubular metal sample chamber and / or the second tubular metal sample chamber is Pt 95 Rh5.

[0023] Preferably, the raw materials of the oxygen fugacity buffer pair are Re, ReO2 and water.

[0024] Preferably, the experimental raw materials for obtaining the supercritical fluid are oxalic acid, ammonia water and NaCl.

[0025] Preferably, step (3) further comprises: soaking the closed sample chamber taken out in resin, making targets, grinding and polishing, so as to obtain the analysis sample containing supercritical fluid inclusions.

[0026] The present invention further provides an analytical sample containing supercritical fluid inclusions obtained according to the above application method.

[0027] The supercritical fluid inclusions in the analytical sample are large in size and can be stably preserved, making them suitable for various analyses such as Raman spectroscopy and LA-ICPMS. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the assembly method of the closed sample chamber obtained by using the olivine product in the embodiment.

[0029] Figure 2 This is a microscopic image of the fluid inclusions obtained in the examples. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is described clearly and completely below in conjunction with the embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] The olivine article for capturing supercritical fluids was prepared according to the following steps:

[0033] (1) Natural olivine without fluid and / or melt inclusions was selected and cut into particles of 1.5 mm × 2.5 mm × 1.5 mm along its c-axis using a rough-surfaced cutter. The surface of the obtained olivine particles after cutting produced relatively dense cracks;

[0034] (2) soaking the cut olivine particles in concentrated hydrofluoric acid with a concentration of 40 wt.% for 2 hours, and then repeatedly washing with ultrapure water to remove the hydrofluoric acid to obtain etched olivine particles;

[0035] (3) The etched olivine particles are placed in an oven at 110° C. and baked for 24 hours to obtain the olivine product for capturing supercritical fluid.

[0036] The surface of the obtained olivine product is uniformly distributed with cracks interconnected into a network and having a width of less than 100 μm.

[0037] Example 2

[0038] Refer to the attached Figure 1 , the fluid inclusions of the supercritical fluid are obtained according to the following steps:

[0039] (1) The olivine product obtained in Example 1 was placed in a Pt 95 Rh5 tube, add oxalic acid, ammonia and NaCl into the tube, then weld the other end of the tube to obtain a closed inner chamber;

[0040] (2) Place a Pt with a length of 10 mm and a diameter of 5 mm, which is sealed at one end, into the closed inner chamber. 95 Rh5 tube, add Re, ReO2 and water into the tube, and then seal the other end with welding to obtain a closed sample outer chamber. Figure 1 As shown;

[0041] (3) placing the sealed sample outer chamber in a special assembly for high temperature and high pressure experiments, and then placing it in a piston cylinder press, setting the experimental conditions to 1.5 GPa and 600°C, and the experimental duration to 3 days;

[0042] (4) After the experiment, take out the experimental device, soak it in resin to make a target, grind and polish the target, and observe it under a microscope.

[0043] The observation results are as follows Figure 2 As shown, it can be seen that the olivine product successfully captured the supercritical fluid, forming clear and complete fluid inclusions with a size of 20-60μm.

[0044] The above embodiments are preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing an olivine product for capturing a supercritical fluid, characterized in that: It includes: (1) natural olivine without fluid and melt inclusions is cut along its C-axis direction, using a rough-surfaced cutter to form natural cracks on the surface of the olivine particles obtained after cutting; (2) soaking the olivine particles in hydrofluoric acid with a mass concentration of 30-40 wt.% until the cracks on the surface of the particles are connected to form a network, thereby obtaining etched particles; (3) Cleaning and drying the etched particles to obtain the olivine product for capturing supercritical fluid.

2. The preparation method according to claim 1, characterized in that: The size of the olivine particles is determined by the sample chamber required for obtaining a high temperature and high pressure experiment of a supercritical fluid, and the volume of the particles is not greater than half the volume of the sample chamber.

3. The preparation method according to claim 1, characterized in that: The size of the olivine particles is 1.5 mm×2.5 mm×1.5 mm.

4. The preparation method according to claim 1, characterized in that: in, Ultrapure water is used for the cleaning, and the temperature for the drying is 110°C.

5. An olivine product for capturing supercritical fluid prepared by the preparation method according to any one of claims 1 to 4.

6. The method for using the olivine product for capturing supercritical fluid according to claim 5, comprising: (1) placing the olivine product into the bottom of a tubular metal sample chamber with one end closed, adding experimental raw materials for obtaining a supercritical fluid into the tubular metal sample chamber, and then closing the other end of the tubular metal sample chamber to obtain a closed sample chamber; (2) placing the closed sample chamber into an experimental device for obtaining a supercritical fluid, and performing a reaction under high temperature and high pressure; (3) After the reaction is completed, the mixture is quenched and the closed sample chamber is taken out to obtain an analysis sample containing supercritical fluid inclusions.

7. The application method according to claim 6, characterized in that: Step (1) specifically includes: (1) placing the olivine product into the bottom of a first tubular metal sample chamber with one end closed, adding experimental raw materials for obtaining supercritical fluid into the first tubular metal sample chamber, and then sealing the other end of the first tubular metal sample chamber to obtain a closed inner chamber; placing the closed inner chamber into the bottom of a second tubular metal sample chamber with one end closed, adding an oxygen fugacity buffer reagent into the second tubular metal sample chamber, and then sealing the other end of the second tubular metal sample chamber to obtain the closed sample chamber.

8. The application method according to claim 7, characterized in that: in, The material of the first tubular metal sample chamber and the second tubular metal sample chamber is Pt 95 Rh5; the oxygen fugacity buffer reagent is Re, ReO2 and water ; The acquisition The experimental raw materials of supercritical fluid are oxalic acid, ammonia and NaCl .

9. The application method according to claim 7, characterized in that: Step (3) also includes: soaking the closed sample chamber taken out in resin, making targets, grinding and polishing, so as to obtain the analysis sample containing supercritical fluid inclusions.

10. An analytical sample containing supercritical fluid inclusions obtained according to the application method of any one of claims 6 to 9.

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