Dual-heating fluorination sample preparation device for refractory mineral oxygen isotope microcell in-situ analysis

Abstract

The utility model relates to a dual-heating fluorination sample preparation device for refractory mineral oxygen isotope microcell in-situ analysis. The dual-heating fluorination sample preparation device comprises a BrF5 gas storage bottle, a first-stage heating fluorination assembly and a second-stage heating fluorination assembly, the first-stage heating fluorination assembly adopts an infrared laser internal heating mode to rapidly heat aerosol particles generated by femtosecond ultraviolet laser denudation; the secondary heating fluorination assembly is used for carrying out secondary heating fluorination on aerosol particles which are not completely reacted in the primary heating fluorination assembly, and the secondary heating fluorination assembly adopts a spiral nickel fluorination pipe, so that a high-temperature fluorination path is increased, the fluorination reaction time is prolonged, and the reaction is more thorough. According to the invention, through continuous two-stage heating fluorination reaction, refractory mineral aerosol particles are completely reacted, fractionation is not generated, and the accuracy of a test result is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of oxygen isotope analysis of silicate oxides, and in particular relates to a double-heating fluorination sample preparation device for in-situ analysis of oxygen isotopes in micro-areas of refractory minerals. Background Art

[0002] BrF5 can react with most silicates and oxides to release O2. The BrF5 fluorination method is a classic method for analyzing the oxygen isotope composition of silicate and oxide minerals. Due to the violent reaction of BrF5 reagent and nickel reaction tube under high temperature conditions, the heating temperature of the nickel reaction tube cannot exceed 700℃. However, refractory minerals such as olivine, garnet, zircon, and magnetite have slow fluorination rates below 700℃. The conventional BrF5 method is used to analyze the oxygen isotope composition of refractory minerals. Due to incomplete reaction, the analysis precision and accuracy are relatively poor, which is difficult to meet the needs of modern precision research.

[0003] In the prior art, there is a new laser probe silicate silicon oxygen isotope micro-area in-situ analysis method (ZL202310332515.0), which uses the classic external heating method. The heating temperature of the nickel reaction tube is 680°C. Due to the small aerosol particles, for quartz, feldspar and other easily fluoridated minerals, fluoridation can be completed quickly within 40 seconds, and the analysis results are stable and reliable. However, for olivine, garnet, zircon, magnetite and other insoluble minerals, fluoridation is difficult to be completed within tens of seconds, which makes the heating fluoridation reaction of the aerosol incomplete, and the reaction time is too long, which will lead to an increase in the background, making it difficult to achieve automatic online analysis, affecting the accuracy of the analysis results. Utility Model Content

[0004] In view of the above analysis, an embodiment of the utility model aims to provide a dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals, so as to solve one or more of the above problems existing in the prior art.

[0005] The purpose of the utility model is achieved in this way:

[0006] A double-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals comprises a BrF5 gas storage bottle, a primary heating fluorination assembly and a secondary heating fluorination assembly; wherein the BrF5 gas storage bottle is used to provide BrF5 gas required for reaction; the primary heating fluorination assembly comprises a cylindrical linear nickel fluorination tube and a CO2 infrared laser, the cylindrical linear nickel fluorination tube has a reaction chamber, laser emitted by the CO2 infrared laser enters the reaction chamber to instantaneously heat aerosol particles, so that the aerosol particles react rapidly with BrF5 gas under high temperature conditions to generate a mixed gas containing target O2 gas; the secondary heating fluorination assembly comprises a spiral nickel fluorination tube, the air inlet port of the spiral nickel fluorination tube is connected to the bottom port of the reaction chamber, the mixed gas enters the spiral nickel fluorination tube, so that the aerosol particles that have not completely reacted in the mixed gas undergo a secondary heating reaction; the air outlet port of the spiral nickel fluorination tube is connected to an O2 enrichment and purification device.

[0007] Furthermore, it also includes a dilution helium source, which is connected to the BrF5 gas storage bottle and is configured to provide helium to dilute the BrF5 gas supplied to the cylindrical linear nickel fluoride tube.

[0008] Furthermore, the spiral nickel fluoride tube has an outer diameter of 6.4 mm, an inner diameter of 3.0 mm, and a length of 2 m.

[0009] Furthermore, the secondary heating fluorination component also includes a resistance furnace, which is used to heat the spiral nickel fluorination tube, and the spiral nickel fluorination tube is installed in the internal heating space of the resistance furnace.

[0010] Furthermore, the resistance furnace includes an outer shell, a heat-resistant inner shell, a resistance wire, and an electronic control module. The heat-resistant inner shell is connected to the outer shell. The resistance wire is arranged in a spiral groove on the inner wall of the heat-resistant inner shell. The groove extends from one end of the heat-resistant inner shell to the corresponding other end. The electronic control module is connected to the resistance wire. The electronic control module is used to control the power of the resistance wire, wherein the spiral nickel-fluoride tube is inserted into the middle of the heat-resistant inner shell.

[0011] Furthermore, the cylindrical linear nickel fluorination tube has an extension tube extending downward; the two ends of the spiral nickel fluorination tube have a front connecting tube and a rear connecting tube, the front connecting tube is connected to the extension tube, and the rear connecting tube is connected to the O2 enrichment and purification device, and the front connecting tube and the rear connecting tube are located outside the resistance furnace.

[0012] Furthermore, the front connecting pipe is detachably connected to the extension pipe via a stainless steel ferrule.

[0013] Furthermore, the cylindrical linear nickel fluoride tube has three ports, the first port is a gas inlet, which is arranged on the upper part of the tube wall of the cylindrical linear nickel fluoride tube and is connected to the reaction chamber, and the gas inlet is connected to the laser ablation sample pool through a pipeline. The second port is the top opening of the reaction chamber; the third port is a gas outlet, and the gas outlet is connected to the secondary heating fluoride component.

[0014] Furthermore, a MgF2 window is sealed at the top opening of the reaction chamber.

[0015] Furthermore, the reaction chamber includes a first space and a second space, which are arranged vertically and coaxially connected. The first space is conical, the top cone diameter of the cone is 3 mm, the cone height is 6 mm, the bottom cone of the cone is connected to the second space, and the second space is a regular cylindrical space, the diameter of the cylindrical space is 1 mm, and the height is 60 mm.

[0016] Compared with the prior art, the dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotopes in refractory minerals provided by the utility model ensures that the refractory mineral aerosol particles react completely without fractionation through a two-stage continuous heating fluorination method of internal heating of the primary heating fluorination component and external heating of the secondary heating fluorination component, thereby making the test results more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0018] Figure 1 A schematic diagram of the structure of a double-heating fluorination sample preparation device for in-situ analysis of oxygen isotopes in micro-areas of refractory minerals provided by the utility model;

[0019] Figure 2 A schematic diagram of the cross-sectional structure of the secondary heating fluorination component provided by the utility model Figure 1 ;

[0020] Figure 3 A schematic diagram of the structure of the secondary heating fluorination assembly provided by the utility model from a top view;

[0021] Figure 4 Schematic diagram of the internal structure of the secondary heating fluorination component provided by the utility model Figure 1 ;

[0022] Figure 5 Schematic diagram of the internal structure of the secondary heating fluorination component provided by the utility model Figure 2 ;

[0023] Figure 6 A schematic structural diagram of a testing system for in-situ analysis of oxygen isotopes in micro-regions of refractory minerals provided by the utility model.

[0024] Reference numerals:

[0025] 10. Primary heating fluorination assembly; 101. Cylindrical linear nickel fluorination tube; 101a. Reaction chamber; 101b. Tube wall; 102. CO2 infrared laser; 103. MgF2 window; 104. Screw cap; 105. First sealing ring; 106. Second sealing ring; 107. Extension tube;

[0026] 20. Secondary heating fluorination component; 201. Outer shell; 202. Heat-resistant inner shell; 203. Resistance wire;

[0027] 30. spiral nickel-fluoride tube; 301. front connecting tube; 302. rear connecting tube;

[0028] 40, air guide assembly; 401, bottom box; 402, middle tube; 403, drive motor; 404, air inlet; 405, air outlet slot; 406, blades; 407, external threaded tube

[0029] 50. Thermal conductive sheet;

[0030] 60. Adapter 2;

[0031] 70. BrF5 gas cylinder;

[0032] 80. Helium source for dilution;

[0033] 90. Adapter 1;

[0034] 100. Femtosecond ultraviolet laser ablation device; 100a. Helium carrier gas purification device;

[0035] 200. Double heating fluorination sample preparation device;

[0036] 300, O2 enrichment and purification device; 300a, first back-flushing helium; 300b, second back-flushing helium;

[0037] 400, diverter valve assembly;

[0038] 500. Gas isotope ratio mass spectrometer; DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined, separated, interchanged and / or rearranged with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0040] In the accompanying drawings, the size and relative size of components may be exaggerated for clarity and / or descriptive purposes. When the exemplary embodiments may be implemented differently, a specific process sequence may be performed in a different order than described. For example, two successively described processes may be performed substantially simultaneously or in an order opposite to the order described. In addition, the same reference numerals represent the same components.

[0041] The terms used here are for the purpose of describing specific embodiments, and are not intended to be restrictive. As used here, unless the context clearly indicates otherwise, the singular forms "one (kind, person)" and "said (the)" are also intended to include plural forms. In addition, when the terms "comprise" and / or "include" and their variations are used in this specification, it is explained that there are stated features, integral bodies, steps, operations, parts, assemblies and / or their groups, but it is not excluded that there are or add one or more other features, integral bodies, steps, operations, parts, assemblies and / or their groups. It should also be noted that, as used here, the terms "substantially", "approximately" and other similar terms are used as approximate terms and not as degree terms, so that they are used to explain the inherent deviations of the measured values, calculated values ​​and / or the values ​​provided that will be recognized by those of ordinary skill in the art.

[0042] Example 1

[0043] A specific embodiment of the utility model is as follows Figures 1 to 5As shown, a double-heating fluorination sample preparation device for in-situ analysis of oxygen isotopes in refractory minerals is disclosed, which may be referred to as the "double-heating fluorination sample preparation device" hereinafter. The double-heating fluorination sample preparation device comprises a BrF5 gas storage bottle 70, a primary heating fluorination assembly 10 and a secondary heating fluorination assembly 20; the BrF5 gas storage bottle 70 is connected to a cylindrical linear nickel fluorination tube 101 of the primary heating fluorination assembly 10 to provide BrF5 gas required for the reaction; the primary heating fluorination assembly 10 has a cylindrical linear nickel fluorination tube 101 and a CO2 infrared laser 102, the cylindrical linear nickel fluorination tube 101 is made of pure nickel tube, and has There are a reaction chamber 101a and a tube wall 101b. The top and bottom ends of the reaction chamber 101a are open. A MgF2 window 103 is sealed at the top opening. The MgF2 window 103 allows the laser emitted by the CO2 infrared laser 102 to enter the reaction chamber 101a. The secondary heating fluorination component 20 has a resistance furnace and a spiral nickel fluorination tube 30 arranged in the resistance furnace. The resistance furnace is used to heat the spiral nickel fluorination tube 30. The air inlet port of the spiral nickel fluorination tube 30 is connected to the bottom port of the reaction chamber 101a of the primary heating fluorination component 10, and the air outlet port of the spiral nickel fluorination tube 30 is connected to the O2 enrichment and purification device.

[0044] In this embodiment, the fluorination sample preparation device also includes a dilution helium source 80, which is connected to the BrF5 gas storage bottle 70 and is configured to provide helium to dilute the BrF5 gas supplied to the cylindrical linear nickel fluorination tube 101; the gas outlet of the BrF5 gas storage bottle 70 is connected to a stainless steel capillary, the inner diameter of the stainless steel capillary is 0.13 mm and the length is 10 m, and the stainless steel capillary is connected to the gas inlet of the cylindrical linear nickel fluorination tube 101 through a three-way valve.

[0045] In this embodiment, the primary heating fluorination component 10 is a CO2 infrared laser device. The CO2 infrared laser 102 can be a MIR10 laser produced by NewVave, USA, with an output power of 30W and an adjustable spot diameter of 100μm to 3000μm. The laser emitted by the CO2 infrared laser 102 transmits through the MgF2 window 103 to quickly heat the aerosol particles passing through the micro cylindrical linear nickel fluorination tube 101 in an internal heating manner, and reacts with BrF5 gas at high temperature to generate a mixed gas containing the target O2 gas. The cylindrical linear nickel fluorination tube 101 has three ports, the first port is a gas inlet, the gas inlet is arranged at the upper part of the tube wall 101b, the gas inlet is connected to the reaction chamber 101a, and the gas inlet is connected to the laser ablation sample pool through a pipeline. The second port is the top opening of the reaction chamber 101a, and the MgF2 window 103 is sealed and arranged on the second port; the third port is a gas outlet, and the gas outlet is connected to the secondary heating fluorination component 20.

[0046] In the present embodiment, the cylindrical linear nickel fluoride tube 101 is a microstructure, which is specifically reflected in that the volume of the reaction chamber 101a is micro, that is, the micro cylindrical linear nickel fluoride tube 101 with the MgF2 window 103 includes a pure nickel tube and a MgF2 window 103, the MgF2 window 103 is connected to the top opening of the pure nickel tube through a screw cap 104, and the screw cap 104 is connected to the top of the pure nickel tube by screwing; the MgF2 window 103 is made of MgF2 glass, and a first sealing ring 105 is provided between the screw cap 104 and the MgF2 window 103, and a second sealing ring 106 is provided between the MgF2 window 103 and the top surface of the pure nickel tube; the first sealing ring 105 and the second sealing ring 106 are both O-type Teflon gaskets. The reaction chamber 101a includes a first space and a second space arranged inside a pure nickel tube. The first space and the second space are arranged vertically and coaxially connected. The first space is conical, the top cone diameter of the cone is 3 mm, the cone height of the cone is 6 mm, the top cone of the cone and the MgF2 glass are sealed by an O-type Teflon gasket, the bottom cone of the cone is connected to the second space, and the second space is a regular cylindrical space with a diameter of 1 mm and a height of 60 mm. The diameter of the cylindrical space is equal to or approximately equal to the beam spot diameter of the CO2 infrared laser, which is beneficial to the concentration of aerosols and laser heating of aerosol particles.

[0047] In this embodiment, the secondary heating fluorination assembly 20 adopts the external heating form of the resistance furnace, and the spiral nickel fluorination tube 30 is installed in the internal heating space of the resistance furnace. The resistance furnace includes several parts such as the furnace body, the heater, and the control system. The furnace body is made of refractory materials. The trace unreacted aerosol particles in the cylindrical linear nickel fluorination tube continue to react with the BrF5 gas through the spiral nickel fluorination tube 30 to generate a mixed gas containing the target O2 gas. The CO2 infrared laser and the resistance furnace are double heated, and the secondary reactor is continuously fluorinated to ensure complete reaction. The spiral nickel fluorination tube 30 also uses a pure nickel tube. The spiral nickel fluorination tube 30 extends in a predetermined direction in a spiral shape. The overall spiral structure can increase the high-temperature fluorination path by more than 4 times, significantly prolonging the fluorination reaction time, making the fluorination reaction more thorough. The spiral nickel fluorination tube 30 has two ports, the air inlet port of the spiral nickel fluorination tube 30 is connected to the gas outlet of the cylindrical linear nickel fluorination tube 101, and the air outlet port of the spiral nickel fluorination tube 30 is connected to the O2 enrichment and purification device; the laser emitted by the CO2 infrared laser passes through the MgF2 window to quickly heat the aerosol particles passing through the reaction chamber 101a of the cylindrical linear nickel fluorination tube 101 in an internal heating manner, and reacts with BrF5 gas at high temperature to generate a mixed gas containing the target O2 gas; the mixed gas carries the incompletely reacted aerosol particles into the spiral nickel fluorination tube 30 for secondary heating at a heating temperature of 680°C, and trace unreacted aerosol particles continue to react with BrF5 gas through the 2-meter-long spiral nickel fluorination tube 30 to generate a mixed gas containing the target O2 gas, and double heating is adopted by the first-stage heating fluorination component 10 and the second-stage heating fluorination component 20, and the two-stage heating reaction realizes continuous fluorination to ensure complete reaction.

[0048] In one preferred embodiment, the internal space of the spiral nickel-fluoride tube 30 is filled with nickel wire, the nickel wire is filled in the space near the air outlet port of the spiral nickel-fluoride tube 30, and the space near the air inlet port of the spiral nickel-fluoride tube 30 is not filled with nickel wire.

[0049] In one preferred embodiment, the spiral nickel-fluoride tube 30 has an outer diameter of 6.4 mm, an inner diameter of 3.0 mm, and a length of 2 m.

[0050] In this embodiment, the secondary heating fluorination assembly 20 can be arranged vertically or horizontally. That is, in the vertical arrangement scheme, the longitudinal height of the resistance furnace is greater than the horizontal length; in the horizontal arrangement scheme, the longitudinal height of the resistance furnace is less than the horizontal length. Among them, the arrangement of the resistance furnace is preferably a horizontal arrangement scheme, which can avoid baking the primary heating fluorination assembly 10 arranged vertically above due to the excessive height of the resistance furnace.

[0051] Exemplarily, the cylindrical linear nickel fluorination tube 101 has an extension tube 107 extending downward, and the extension tube 107 is integrally formed with the cylindrical linear nickel fluorination tube 101. The extension tube 107 is connected to the bottom opening of the cylindrical linear nickel fluorination tube 101 and extends downward from the bottom opening. The fluorination reaction in the cylindrical linear nickel fluorination tube 101 is mainly completed in the reaction chamber 101a, and does not react in the extension tube 107. The extension tube 107 only serves to connect the reaction chamber 101a with the cylindrical linear nickel fluorination tube 101. The air inlet port and the air outlet port of the spiral nickel fluorination tube 30 are both located outside the resistance furnace. The two ends of the spiral nickel fluorination tube 30 have a front connecting tube 301 and a rear connecting tube 302. The part between the front connecting tube 301 and the rear connecting tube 302 is a spiral structure, and the middle spiral structure part is integrally formed with the front connecting tube 301 and the rear connecting tube 302; the front connecting tube 301 is located on the air inlet port side, and the rear connecting tube 302 is located on the air outlet port side. The front connecting tube 301 is connected to the extension tube 107 through an adapter 90, and the rear connecting tube 302 is connected to the O2 enrichment and purification device. The front connecting tube 301 and the rear connecting tube 302 are straight pipe sections, and the front connecting tube 301 and the rear connecting tube 302 are located outside the resistance furnace. Only the spiral structure part is located in the resistance furnace for heating, and the front connecting tube 301 and the rear connecting tube 302 are not heated.

[0052] In this embodiment, the resistance furnace can adopt an existing resistance furnace, such as a resistance furnace commonly used in laboratories, without the need for additional purchase, and the cost is low.

[0053] In order to improve the heating effect of the resistance furnace on the spiral nickel-fluoride tube 30, this embodiment makes corresponding improvements on the structure of the existing resistance furnace according to the spiral nickel-fluoride tube 30. Specifically, the resistance furnace of this embodiment includes an outer shell 201, a heat-resistant inner shell 202, a resistance wire 203, and an electric control module. The heat-resistant inner shell 202 is connected to the outer shell 201, and the outer shell 201 and the heat-resistant inner shell 202 constitute a furnace body; heat insulation cotton can be arranged between the heat-resistant inner shell and the outer shell; the resistance wire 203 is arranged in a spiral groove opened on the inner wall of the heat-resistant inner shell 202, and the groove extends from one end of the heat-resistant inner shell 202 to the corresponding other end. The electric control module is connected to the resistance wire 203, and the electric control module is used to control the power of the resistance wire 203, wherein the spiral nickel-fluoride tube 30 is inserted into the middle of the heat-resistant inner shell 202.

[0054] In this embodiment, the electric control module controls the current to flow through the resistance wire 203, so that the resistance wire 203 heats up. After the resistance wire 203 heats up, it heats the spiral nickel-fluoride tube 30. By controlling the power of the current through the electric control module, the temperature generated by the resistance wire 203 can be controlled to achieve the purpose of temperature control.

[0055] Since the resistance wire 203 is arranged on the outside of the spiral nickel fluoridation tube 30, there is a difference between the temperature at the center of the resistance furnace and the heating temperature of the resistance wire 203 at the furnace wall. The temperature is high near the furnace wall, and the temperature at the center is slightly lower. The temperature at different positions in the furnace is not uniform. The inner heating temperature of the spiral nickel fluoridation tube 30 is slightly lower than the outer temperature, which will affect the accuracy of temperature monitoring. Slight fluctuations in the heating temperature will also affect the fluorination reaction effect in the spiral nickel fluoridation tube 30. Based on this, in one of the optional embodiments, the resistance furnace also includes an air guide component 40, which is arranged in the heat-resistant inner shell 202, and is used to circulate the heat generated by the resistance wire 203 in the heat-resistant inner shell 202. By setting the air guide component 40, the heat generated by the resistance wire 203 can be circulated in the heat-resistant inner shell 202, and the heat of the spiral nickel fluoridation tube 30 can be guided to the inner side of the spiral nickel fluoridation tube 30, so that the temperature at different positions in the resistance furnace is uniform, thereby achieving balanced heating of the spiral nickel fluoridation tube 30 and ensuring the fluorination reaction effect.

[0056] Specifically, the air guide assembly 40 includes a bottom box 401, a middle cylinder 402, and a driving motor 403. The side wall of the middle cylinder 402 is regularly provided with multiple air inlets 404. An air outlet groove 405 is provided on the side of the bottom box 401 opposite to the heat-resistant inner shell 202. The air outlet groove 405 is located between the heat-resistant inner shell 202 and the spiral nickel-fluoride tube 30. The middle cylinder 402 is connected and communicated with the bottom box 401. The driving motor 403 is connected to the bottom of the bottom box 401, and the driving shaft of the driving motor 403 is inserted into the bottom box 401 and extends into the middle cylinder 402. The driving shaft of the driving motor 403 located in the middle cylinder 402 is provided with blades 406.

[0057] After the driving motor 403 is started, the driving shaft of the driving motor 403 can drive the blades 406 to rotate rapidly, generating an airflow blowing from the bottom direction of the middle cylinder 402. The airflow enters the middle cylinder 402 from the air inlet 404. Since the air inlet 404 is close to the resistance wire 203, the hot airflow near the resistance wire 203 moves toward the inside of the spiral nickel-fluoride tube 30. After the airflow enters the bottom box 401, it is blown out from the air outlet slot 405. Since the air outlet slot 405 is located between the heat-resistant inner shell 202 and the spiral nickel-fluoride tube 30, the airflow flows back from between the heat-resistant inner shell 202 and the spiral nickel-fluoride tube 30 into the heat-resistant inner shell 202, forming an airflow circulation. In this way, the heat of the heat-resistant inner shell 202 is evenly distributed.

[0058] In one optional implementation, the middle cylinder 402 may be made of copper or other materials with good thermal conductivity.

[0059] In order to further improve the heating uniformity in the resistance furnace, a plurality of heat-conducting sheets 50 are arranged at intervals in the resistance furnace. The heat-conducting sheets 50 are arranged in the heat-resistant inner shell 202. One end of the heat-conducting sheet 50 is connected to the outer wall of the middle cylinder 402, and the other end is overlapped to the outer wall of the spiral nickel-fluoride tube 30. By providing the heat-conducting sheet 50, the heat near the resistance wire 203 can be directly introduced into the inner area of ​​the side wall of the spiral nickel-fluoride tube 30, further improving the temperature balance of the heat-resistant inner shell 202. The material of the heat-conducting sheet 50 can also be made of copper, a material with good thermal conductivity.

[0060] The heat conductive sheet 50 is at the overlapping end of the spiral nickel fluoride tube 30, and its end is within the cross-sectional area of ​​the spiral nickel fluoride tube 30, so that the heat conductive sheet 50 does not extend into the gap between the spiral nickel fluoride tube 30 and the resistance wire 203, preventing it from obstructing the blowing of the reflux airflow.

[0061] The heat conducting sheet 50 is also connected to the middle cylinder 402 in a spiral shape and is evenly connected to the spiral nickel-fluoride tube 30 .

[0062] The resistance wire 203 and the spiral nickel-fluoride tube 30 are staggered, so that when the resistance wire 203 and the spiral nickel-fluoride tube 30 are in the same cross section, each part of the resistance wire 203 is exactly located between two adjacent spiral sections of the spiral nickel-fluoride tube 30; the air inlet 404 corresponds to the position of the resistance wire 203. By staggering the resistance wire 203 and the spiral nickel-fluoride tube 30, the heat radiation of the resistance wire 203 is exactly in two adjacent spiral sections of the spiral nickel-fluoride tube 30, and the heat radiation is more balanced.

[0063] In one optional embodiment, Figure 5 As shown, the rear connecting tube 302 is detachably connected to the pipeline of the O2 enrichment and purification device through the adapter 60. The rear connecting tube 302 has an inner portion extending outward from the outside of the resistance furnace and extending to the outside of the bottom box 401. The connection between the rear connecting tube 302 and the adapter 60 is arranged on the outside of the resistance furnace for easy replacement operation. A hollow externally threaded tube 407 is connected to the top center of the bottom box 401, and an internal thread is provided on the inner wall of the bottom end portion of the middle tube 402. The middle tube 402 is threadedly connected to the externally threaded tube 407, and the externally threaded tube 407 is connected to the bottom box 401 and the middle tube 402. The front connecting tube 301 is detachably connected to the extension tube 107 through the adapter 90. The rear connecting tube 302 is detachably connected to the pipeline of the O2 enrichment and purification device through the adapter 60, so that the spiral nickel fluoride tube 30 can be replaced.

[0064] In one of the optional embodiments, both adapter 1 90 and adapter 2 60 can use Swagelok stainless steel ferrules, and stainless steel gaskets or Teflon gaskets are used for sealing during connection. Exemplarily, adapter 1 90 is a Swagelok stainless steel ferrule with a right-angle structure, and adapter 2 60 is a Swagelok stainless steel ferrule with a straight-line structure. The front connecting tube 301 is connected to the extension tube 107 using a right-angle Swagelok stainless steel ferrule, so that the extension tube 107 can be arranged vertically as a whole, and the front connecting tube 301 can be arranged horizontally, which can avoid baking the primary heating fluorination component 10 arranged vertically above due to the excessive height of the resistance furnace.

[0065] This embodiment also discloses a micro-area in-situ analysis and testing system for oxygen isotopes of refractory minerals. Figure 6 As shown, it includes a helium carrier gas purification device 100a, a femtosecond ultraviolet laser ablation device 100, the aforementioned double heating fluorination sample preparation device 200, an O2 enrichment and purification device 300 and a gas isotope ratio mass spectrometer 500 which are sequentially arranged on the analysis gas path;

[0066] The helium carrier gas purification device 100a has a liquid nitrogen cold trap filled with silica gel and a heating activation device; the helium carrier gas and the back-blowing helium gas both use 5N high-purity helium, but it still contains trace impurities O2. When collecting the sample O2, the impurity O2 will also be enriched, resulting in an increase in the background. In this embodiment, a large-capacity liquid nitrogen cold trap filled with silica gel is used to remove the trace impurity O2 in the high-purity helium gas, thereby reducing the system background;

[0067] The femtosecond ultraviolet laser ablation device 100 comprises a femtosecond laser, a laser ablation platform and a high-purity helium source; a sample pool for containing a sample to be tested is provided in the laser ablation platform, and the femtosecond laser is configured to emit a femtosecond ultraviolet laser to the surface of the sample to be tested in the sample pool, so as to ablate refractory mineral aerosol particles from the sample to be tested; the high-purity helium source is configured to provide helium carrier gas, so as to blow the ablated refractory mineral aerosol particles out of the sample pool;

[0068] The double-heating fluorination sample preparation device 200 includes a primary heating fluorination component 10 and a secondary heating fluorination component 20; the laser emitted by the CO2 infrared laser 102 passes through the MgF2 window 103 to quickly heat the aerosol particles passing through the micro cylindrical linear nickel fluorination tube 101 in an internal heating manner, and reacts with BrF5 gas at high temperature to generate a mixed gas containing target O2 gas; the mixed gas carries the incompletely reacted aerosol particles into the spiral nickel fluorination tube 30 for secondary heating, and continues to react with BrF5 gas to generate a mixed gas containing target O2 gas, and adopts dual heating of the primary heating fluorination component 10 and the secondary heating fluorination component 20, and the two-stage heating reaction realizes continuous fluorination to ensure complete reaction.

[0069] The O 2 enrichment and purification device 300 is connected to the gas outlet port of the secondary heating fluorination component 20 , and is used to collect and purify the target O 2 gas in the reacted mixed gas in the secondary heating fluorination component 20 .

[0070] The gas isotope ratio mass spectrometer 500 has a mass spectrometer host, which is connected to the O2 enrichment and purification device through a diverter valve assembly 400 and is used to measure the three oxygen isotope compositions of the target O2 gas.

[0071] The test steps are as follows: Use a silica gel liquid nitrogen cold trap purification device to remove trace impurities O2 in helium and reduce the system background; before using the liquid nitrogen cold trap filled with silica gel, heat it to 300℃ in the system to purge and degas for 3 days to reduce the system background to below 200mV. The purified helium is divided into three paths through a three-way valve, one for helium carrier gas, and the other two for the first back-blowing helium 300a and the second back-blowing helium 300b. Furthermore, after the end of each day's experiment, heat the silica gel cold trap to 300℃ for activation, and use helium to back-blow and degas for more than 12 hours. A femtosecond laser is used to etch out silicate oxide aerosol particles from the refractory mineral sample to be tested in the sample pool. The etched silicate oxide aerosol particles are first carried by a helium carrier gas into a cylindrical linear nickel fluorination tube 101 of a primary heating fluorination component 10. A CO2 infrared laser 102 emits an infrared laser into a reaction chamber 101a to heat the aerosol particles carried by the helium carrier gas and rapidly react with BrF5 gas under high temperature conditions to generate a mixed gas containing target O2 gas. The remaining trace aerosol particles that have not reacted completely enter a spiral nickel fluorination tube 30 of a secondary heating fluorination component 20. The heating temperature of the resistance furnace is 680°C. The trace aerosol particles continue to react with BrF5 gas under 680°C to ensure that the fluorination reaction is complete without fractionation. The mixed gas generated in the spiral nickel fluorination tube 30 is passed through an O2 enrichment, purification and separation device to collect the purified target O2 gas, which is then fed into a mass spectrometer for testing to obtain a trioxygen isotope composition.

[0072] Compared with the prior art, the dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotopes in refractory minerals provided in this embodiment uses a two-stage continuous heating fluorination method of internal heating of the primary heating fluorination component and external heating of the secondary heating fluorination component to ensure that the refractory mineral aerosol particles react completely without fractionation, making the test results more accurate and significantly improving the accuracy of the results of in-situ analysis of oxygen isotopes in refractory minerals. Among them, the first-stage heating fluorination component adopts internal heating to quickly heat the aerosol particles generated by femtosecond ultraviolet laser ablation. The first-stage heating fluorination component adopts a cylindrical linear nickel fluorination tube. The reaction chamber of the cylindrical linear nickel fluorination tube is a regular cylinder. The diameter of the cylindrical reaction chamber is only 1mm, which is consistent with the beam spot diameter of the infrared laser, ensuring that all aerosol particles are concentrated in the focus of the infrared laser and are quickly heated and fluorinated. At the same time, it avoids the temperature in the reaction chamber from being too high and the nickel tube wall reacting with the fluorinating agent; the gas outlet end of the first-stage heating fluorination component is directly connected to the second-stage heating fluorination component. The second-stage heating fluorination component adopts a spiral nickel fluorination tube, which increases the high-temperature fluorination path by more than 4 times, prolongs the fluorination reaction time, and can make the aerosol particles that have not reacted completely in the first-stage heating fluorination component further react, making the fluorination reaction more complete without fractionation, realizing the high-precision in-situ oxygen isotope analysis of refractory silicate and oxide mineral micro-areas by femtosecond ultraviolet laser probe.

[0073] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above are only specific implementation methods of the present application and are not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A double-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals, characterized in that: It comprises a BrF5 gas cylinder, a primary heating fluorination component and a secondary heating fluorination component; wherein the BrF5 gas cylinder is used to provide the BrF5 gas required for the reaction; the primary heating fluorination component comprises a cylindrical linear nickel fluorination tube and a CO2 infrared laser, the cylindrical linear nickel fluorination tube has a reaction chamber, the laser emitted by the CO2 infrared laser enters the reaction chamber to instantaneously heat the aerosol particles, and the aerosol particles react rapidly with the BrF5 gas under high temperature conditions to generate a mixed gas containing the target O2 gas; the secondary heating fluorination component comprises a spiral nickel fluorination tube, the air inlet port of the spiral nickel fluorination tube is connected to the bottom port of the reaction chamber, the mixed gas enters the spiral nickel fluorination tube, and the aerosol particles that have not reacted completely in the mixed gas undergo a secondary heating reaction; the air outlet port of the spiral nickel fluorination tube is connected to an O2 enrichment and purification device.

2. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 1, characterized in that: It also includes a dilution helium source, which is connected to the BrF5 gas storage bottle and is configured to provide helium to dilute the BrF5 gas supplied into the cylindrical linear nickel fluoride tube.

3. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 1 or 2, characterized in that: The spiral nickel-fluoride tube has an outer diameter of 6.4 mm, an inner diameter of 3.0 mm, and a length of 2 m.

4. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 1, characterized in that: The secondary heating fluorination assembly also includes a resistance furnace, and the spiral nickel fluorination tube is installed in the internal heating space of the resistance furnace.

5. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 4, characterized in that: The resistance furnace includes an outer shell, a heat-resistant inner shell, a resistance wire, and an electric control module. The heat-resistant inner shell is connected to the outer shell. The resistance wire is arranged in a spiral groove opened in the heat-resistant inner shell. The groove extends from one end of the heat-resistant inner shell to the corresponding other end. The electric control module is connected to the resistance wire. The electric control module is used to control the power of the resistance wire, wherein the spiral nickel-fluoride tube is inserted into the middle of the heat-resistant inner shell.

6. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 4 or 5, characterized in that: The cylindrical linear nickel fluorination tube has an extension tube extending downward; the two ends of the spiral nickel fluorination tube have a front connecting tube and a rear connecting tube, the front connecting tube is connected to the extension tube, and the rear connecting tube is connected to the O2 enrichment and purification device, and the front connecting tube and the rear connecting tube are located outside the resistance furnace.

7. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 6, characterized in that: The front connecting pipe is detachably connected to the extension pipe via a stainless steel ferrule.

8. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 1, characterized in that: The cylindrical linear nickel fluoride tube has three ports, the first port is a gas inlet, the gas inlet is arranged on the upper part of the tube wall of the cylindrical linear nickel fluoride tube and is connected to the reaction chamber, the gas inlet is connected to the laser ablation sample pool through a pipeline, the second port is the top opening of the reaction chamber; the third port is a gas outlet, and the gas outlet is connected to the secondary heating fluoride component.

9. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 8, characterized in that: A MgF2 window is sealed at the top opening of the reaction chamber.

10. The dual-heating fluorination sample preparation device for in-situ analysis of oxygen isotope micro-areas of refractory minerals according to claim 9, characterized in that: The reaction chamber includes a first space and a second space, which are arranged vertically and coaxially connected. The first space is conical, the top cone diameter of the cone is 3 mm, the cone height is 6 mm, the bottom cone of the cone is connected to the second space, and the second space is a regular cylindrical space, the diameter of the cylindrical space is 1 mm, and the height is 60 mm.

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