Method for in-situ determination of mineral volume and solubility in DAC

Abstract

The invention provides a method for in-situ determination of mineral volume and solubility in DAC, which comprises the following steps: loading a to-be-measured sample and a solvent into a DAC sample cavity, generating an initial three-dimensional image of the to-be-measured sample at normal temperature and normal pressure through a Raman spectrum three-dimensional imaging technology, and calculating the initial volume # imgabs0 # of the to-be-measured sample; after the temperature and pressure are increased to a target condition and stabilized, generating a real-time three-dimensional image of the to-be-detected sample through a Raman spectrum three-dimensional imaging technology, and calculating the volume # imgabs1 # of the to-be-detected sample under the target condition; and calculating the mass difference value of the sample under the normal temperature, normal pressure and target conditions by combining the volume compression coefficient and thermodynamic parameters of the to-be-detected sample, and calculating the solubility # imgabs2 # according to the mass difference value and the mass of the solvent. The method is simple to operate, high in accuracy and wide in universality, can solve the problems of dependence on a standard curve, complex experimental operation, sensitivity to instrument performance and environmental factors and the like in a traditional method, and is suitable for in-situ solubility determination of minerals and organic matters.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond anvil cell (DAC), and particularly to a method for in-situ determination of the volume and solubility of minerals in a DAC. Background Art

[0002] The diamond anvil cell combined with a temperature control system can generate high-temperature and high-pressure conditions, and is the most commonly used preferred portable device for simulating the static high-pressure environment of the deep sea and abyss as well as the high-temperature and high-pressure conditions inside planets. However, achieving in-situ accurate measurement of the sample volume in a DAC faces significant technical challenges, which not only stem from the tiny size of the sample, but also because it is in an extreme high-pressure or high-temperature and high-pressure environment. Currently, the commonly used volume measurement techniques include optical microscope observation, in-situ resistivity measurement, and in-situ sound velocity measurement, etc. Among them, the optical microscope observation method is only applicable to samples with regular shapes, high transparency, and small deformations under high temperature and high pressure; the in-situ resistivity measurement method requires the sample to have certain conductivity, stable structure, and uniform internal structure, but the samples in a DAC often show non-uniformity due to pressure gradients and temperature gradients; the in-situ sound velocity measurement method not only requires the sample to maintain a stable structure under high temperature and high pressure without plastic deformation, but also has complex operations, and multiple factors need to be considered in data analysis.

[0003] Raman spectroscopy is a powerful tool for rapidly, non-destructively, and intelligently characterizing the micro-region structure of substances. Its three-dimensional imaging ability can not only obtain the three-dimensional stereoscopic image and volume information of the sample, but also provide the Raman spectrum and structural details of each pixel point. Combining the DAC with Raman spectroscopy three-dimensional imaging technology can in-situ determine the volume change and solubility of carbonates under high temperature and high pressure.

[0004] However, the current mainstream technical method based on the positive correlation principle between the molecular Raman vibration intensity and concentration has obvious limitations. First of all, this method requires calibration of the standard curve, but the intensity of the Raman signal is extremely sensitive to the instrument state and laboratory conditions, resulting in limited universality of the standard curve, which is only applicable to specific Raman spectrometers and DAC devices under specific environments, and at the same time increases the workload of pre-calibration. At the same time, under high temperature and high pressure, the characteristic Raman peak shapes of the solute [CO 3 2- and the solvent H 2 O change, seriously affecting the accuracy of the fitting results. As the temperature and pressure gradually increase, the symmetric stretching vibration peak of [CO 3 2- quickly becomes weaker and broader, and when the temperature exceeds 400 °C, due to the increased hydrolysis degree of [CO 3 2- , the Raman vibration peak of [HCO 3 - appears. Due to [CO​​​​3 2- and [HCO 3 - have different Raman scattering cross-sections, and the difference in their coefficients needs to be considered, which undoubtedly further increases the complexity of experimental data processing and interpretation. Moreover, under high temperature and high pressure, the characteristic Raman peaks of H 2 O show phenomena such as weakening, broadening, splitting, and peak shape asymmetry, seriously interfering with peak shape fitting and peak intensity calculation, resulting in large deviations in the measurement results of carbonate solubility. Summary of the Invention The object of the present invention is to combine DAC with high-resolution Raman spectroscopy three-dimensional imaging technology to propose a more universal, simple to operate method that can accurately and in-situ measure the volume and solubility of carbonate minerals in DAC, so as to solve the problems of complex experimental operations, low universality, and affecting accuracy faced by the prior art.

[0005] To achieve the above invention object, the technical solution provided by the present invention includes the following steps: S11. Load the sample to be measured and the solvent into the DAC sample chamber, generate the initial three-dimensional stereoscopic image of the sample to be measured at normal temperature and pressure through Raman spectroscopy three-dimensional imaging technology, and calculate the initial volume of the sample to be measured according to the initial three-dimensional stereoscopic image ; S12. After heating and pressurizing to the target conditions and stabilizing, generate the real-time three-dimensional stereoscopic image of the sample to be measured through Raman spectroscopy three-dimensional imaging technology, and calculate the volume of the sample to be measured under the target conditions ; S13. Combine the bulk compressibility coefficient and thermodynamic parameters of the sample to be measured to calculate the mass difference of the sample under normal temperature and pressure and the target conditions, and calculate the solubility according to the mass difference and the solvent mass .

[0006] Further, the solvent is deionized aqueous solution.

[0007] Further, generating the three-dimensional stereoscopic Raman image of the sample to be measured through Raman spectroscopy three-dimensional imaging technology specifically includes: under the Raman microscope, setting the Raman spectroscopy three-dimensional imaging parameters, collecting the Raman spectroscopy data of the sample to be measured, and reconstructing the three-dimensional stereoscopic Raman image of the sample to be measured according to the collected Raman spectroscopy data.

[0008] Further, the Raman spectroscopy three-dimensional imaging parameters include: imaging area size, scanning step size, single-spectrum integration time, laser power, and scanning times.

[0009] Further, the initial volume of the sample to be measured is calculated by combining the initial three-dimensional stereoscopic image and the volume calibration parameter , and the calculation of the volume calibration parameter specifically includes: ,​​ A three-dimensional stereoscopic image of a sample to be measured is obtained by computed tomography to calculate the scanned volume of the sample to be measured. ; A three-dimensional Raman spectrum of the sample to be measured is obtained by Raman spectroscopy three-dimensional imaging technology to calculate the measured volume of the sample to be measured. ; Calculate the volume calibration parameter according to the scanned volume and the measured volume, and the calculation formula is: .

[0010] Furthermore, calculate the volume of the sample to be measured under target conditions according to the initial volume and the real-time three-dimensional stereoscopic image , specifically including: Calculate the Raman measurement volume of the sample to be measured according to the real-time three-dimensional stereoscopic image , According to the Raman measurement volume of the sample to be measured and the volume calibration parameter calculate the volume of the sample to be measured under target conditions, and the calculation formula is as follows: .

[0011] Furthermore, calculate the solubility of the sample to be measured under target conditions according to the initial volume and the real-time three-dimensional stereoscopic image , specifically including: Based on the initial volume of the sample to be measured and its density at normal temperature and pressure calculate the initial mass of the sample to be measured , and the calculation formula is: ; Based on the volume of the DAC sample chamber and the density of water at normal temperature and pressure, combined with the initial volume of the sample to be measured, calculate the mass of the solvent ; Based on the real-time three-dimensional stereoscopic image, the bulk compressibility coefficient and the thermodynamic parameters of the sample to be measured, calculate the mass of the sample to be measured under target conditions ; Calculate the dissolved amount of the sample to be measured , and after unit conversion, obtain the amount of substance of the dissolved sample to be measured n , and combine with the solvent mass to calculate the solubility of the sample to be measured under target conditions , and the calculation formula is as follows: .

[0012] Furthermore, the method is applicable to all Raman-active minerals and organic matters.

[0013] Further, the method is applicable to carbonates, silicates, sulfates, phosphates, etc.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Simple operation. The present invention does not require calibration of the standard curve, thus avoiding the error caused by the "non-standard" standard curve; at the same time, it greatly reduces the complexity and tediousness of the experimental operation. The present invention has no special or additional requirements for the DAC model and the sample loading method, and after setting the Raman spectrum parameters, the three-dimensional imaging data acquisition will run automatically. Compared with in-situ resistivity and sound velocity measurements, the experimental operation of the method is very simple.

[0015] 2. High accuracy. The traditional method for in-situ determination of carbonate solubility is to directly measure the content of [CO 3 2- in the solution. The present invention takes a different approach and obtains the amount of dissolved substance by quantitatively studying the change in carbonate volume, and then obtains the solubility of the carbonate to be measured under the given temperature and pressure conditions. The present invention does not require direct measurement of the Raman spectrum of the solution, thus avoiding the fitting error caused by factors such as the peak shape changes of the solute [CO 3 2- and the solvent H 2 O, and the appearance of the Raman vibration peak of [HCO 3 - at high temperatures. At the same time, in the measurement of the mineral volume, the appearance of the Raman vibration peak reflects the intrinsic molecular structure and composition of the sample, and is not affected by factors such as the sample size and geometry, temperature and pressure gradients. Therefore, the present invention can avoid the interference of these external factors on the measurement accuracy.

[0016] 3. Wide universality. First, the present invention does not rely on the relative peak intensity of the Raman peak to obtain the solubility of carbonates, so it is not affected by the state of the Raman spectrometer and laboratory conditions. This method is applicable to any Raman instrument in any laboratory. Second, the present invention is applicable to all substances with Raman vibrational activity, and the vast majority of geological minerals and organic substances have characteristic Raman vibration peaks, so the applicable range of this method is very wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only the preferred embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 is a schematic diagram of the overall process of a method for in-situ determination of mineral volume and solubility in a DAC provided by an embodiment of the present invention. ​​​Specific Embodiments

[0019] The principles and features of the present invention will be described below in conjunction with the accompanying drawings. The listed embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0020] Refer to Figure 1 , an embodiment of the present invention provides a method for in-situ determination of the volume and solubility of minerals in DAC, including the following steps: S11. Load the sample to be tested and the solvent into the DAC sample chamber, generate an initial three-dimensional stereoscopic image of the sample to be tested at normal temperature and pressure through Raman spectroscopy three-dimensional imaging technology, and calculate the initial volume of the sample to be tested according to the initial three-dimensional stereoscopic image .

[0021] In this embodiment, a three-dimensional stereoscopic Raman image of the sample to be tested is generated through Raman spectroscopy three-dimensional imaging technology. Specifically, under a Raman microscope, set the Raman spectroscopy three-dimensional imaging parameters, collect the Raman spectroscopy data of the sample to be tested, and reconstruct the three-dimensional stereoscopic Raman image of the sample to be tested according to the collected Raman spectroscopy data.

[0022] Among them, the Raman spectroscopy three-dimensional imaging parameters include: imaging area size, scanning step size, single-spectrum integration time, laser power, and number of scans.

[0023] As a preferred embodiment, in this embodiment, the initial volume of the sample to be tested is calculated by combining the initial three-dimensional stereoscopic image and the volume calibration parameter , and the calculation of the volume calibration parameter specifically includes: Obtain a three-dimensional stereoscopic image of the sample to be tested through computed tomography (CT spatial resolution less than 500 nm) to calculate the scanned volume of the sample to be tested ; Load the sample to be tested and the solvent into the DAC sample chamber, and obtain a three-dimensional stereoscopic Raman spectrum of the sample to be tested through Raman spectroscopy three-dimensional imaging technology to calculate the tested volume of the sample to be tested ; Calculate the volume calibration parameter according to the scanned volume and the tested volume. The calculation formula is: .

[0024] S12. After heating and pressurizing to the target conditions and stabilizing, generate a real-time three-dimensional stereoscopic image of the sample to be tested through Raman spectroscopy three-dimensional imaging technology; calculate the volume of the sample to be tested under the target conditions .

[0025] ​The solvent is a deionized water solution, which is widely applicable to the coexistence system of minerals and various fluids in subduction zones and orogenic belts in the field of geological science.

[0026] S13. Combine the sample's volume compressibility and thermodynamic parameters to obtain the mass difference of the sample under initial and target conditions. The ratio of this to the initial solvent mass is the solubility. .

[0027] The volume of the sample under target conditions is calculated based on the initial volume of the sample and the real-time three-dimensional image. , including the following operations: S21. Calculate the Raman test volume of the sample to be tested based on the real-time three-dimensional image .

[0028] S22, according to the Raman test volume of the sample to be tested and volume calibration parameters Calculate the volume of the sample under target conditions as follows: .

[0029] Calculate the solubility of the sample under target conditions based on the initial volume and real-time 3D images , including the following operations: S31, based on the initial volume of the sample to be tested Its density at room temperature and pressure Calculate the initial mass of the sample to be tested , the calculation formula is: .

[0030] S32. Based on the volume of the DAC sample chamber and the density of water at room temperature and pressure, combined with the initial volume of the sample to be tested, calculate the mass of the solvent .

[0031] S33, calculate the mass of the sample under target conditions based on the real-time three-dimensional image, volume compression coefficient and thermodynamic parameters of the sample .

[0032] S34. Calculate the dissolved amount of the sample to be tested After unit conversion, the amount of substance dissolved in the sample to be tested is obtained n , combined with the solvent mass, calculate the solubility of the sample under target conditions , the calculation formula is as follows: .

[0033] The method provided in this embodiment is applicable to all minerals and organic matters with Raman activity, including (but not limited to) carbonates, silicates, sulfates, phosphates, etc.

[0034] The following will respectively illustrate how to use the above method to in-situ measure the volume and solubility of carbonate minerals in DAC through two specific embodiments.

[0035] (I) Method for in-situ measuring the volume of carbonate minerals in DAC: First, determine the volume calibration parameter. Raman spectroscopy is very sensitive to the molecular structure of the sample, and Raman signals will be generated in any area covered by the laser spot. Therefore, an important influencing factor for the spatial resolution of confocal Raman imaging is the spot size. The main factors affecting the spot size are the numerical aperture of the objective lens and the diamond anvil in the DAC. Ultra-long focal length objective lenses are often used for DAC imaging, and their numerical apertures are between 0.25 and 0.45. At the same time, due to the difference in refractive index between diamond in the DAC and air and the influence of interface effects, etc., when the laser beam emitted from the laser passes through the diamond anvil and is focused on the sample, the spot becomes larger, resulting in a deviation between the sample volume obtained by three-dimensional Raman imaging and the actual volume. However, the influence of the objective lens numerical aperture and the diamond anvil on the spot size is basically fixed. Therefore, as long as the volume calibration parameter (i.e., the calibration coefficient for the deviation between the actual volume of the sample and the Raman test volume) is determined, the accurate volume of the sample in the DAC can be obtained through three-dimensional Raman imaging.

[0036] Computed tomography (CT) technology is an advanced imaging technology that can provide three-dimensional stereoscopic images and volume information of samples at the sub-micron scale (note: CT cannot be used in combination with DAC and can only scan the volume of exposed samples at room temperature and normal pressure). In this embodiment, CT is used to accurately measure the volume of the standard sample and establish the conversion coefficient between it and the three-dimensional Raman test volume, that is, the volume calibration parameter. The specific method is as follows: Calcium carbonate calcite CaCO 3 is one of the most common minerals on the earth's surface. Here, calcite is selected as an example to describe the specific implementation process of this embodiment.

[0037] (1) Select randomly crushed natural calcite samples as the standard sample, scan the samples with the help of CT (Xradia 620 Versa) technology, and parse the data through VGStudio Max 3.0 software to obtain the initial three-dimensional stereoscopic image and CT volume of the standard sample =4,244,757.629 (Spatial resolution 312.5 nm).

[0038] (2) Load the standard sample and solvent (deionized water is used here) into the DAC sample chamber, focus (Olympus 20×) under a Raman microscope (WITec Alpha300), and set the Raman spectrum 3D imaging parameters. Imaging area X range: 320 ; Y range: 210 ; Z range: 200 ; Scan step: 2 ; Laser power: 50mW; Single spectrum integration time: 0.05s; Number of scans: 1. After setting, the instrument automatically collects Raman spectra and scans layer by layer.

[0039] (3) Use the Raman instrument’s built-in data processing software (WITec FIVE 5.3) and ImageJ software to reconstruct the 3D image and volume of the calcite standard sample. , and then get the volume calibration parameters .

[0040] (4) After obtaining the volume calibration parameters, the formal experiment can be carried out. Select another experimental sample (this experiment takes another randomly damaged calcite as an example) and load it into the DAC sample chamber with deionized water, set the target temperature and pressure conditions, and conduct the experiment at room temperature and pressure. Use the same method as above to obtain the Raman test volume of the sample , the actual volume of the sample is obtained by parameter calibration This result is consistent with the result of CT test (763,142.7205 , spatial resolution 328.8nm) is basically consistent, with an error of no more than 0.02%. This once again verifies the reliability of the scheme.

[0041] It should be noted that the calibration work of this embodiment selects carbonate calcite as the standard sample, mainly based on the following considerations: (1) Calcite is one of the most common minerals on the surface and is also a widely used research object in DAC experiments. Calcite is generally recognized as a standard sample; (2) The solubility of calcite in deionized water at room temperature and pressure is almost zero, which will not interfere with the determination of volume calibration parameters. The calibration parameters obtained are more accurate and can be widely used for volume determination of various minerals such as carbonates, silicates, sulfates, and phosphates in DAC. In addition, this formal experiment was completed at room temperature and pressure in DAC, with the purpose of comparing it with the measurement results of CT again (CT cannot scan samples under high temperature and high pressure) to verify the accuracy of volume measurement. The experimental operation of high temperature and high pressure is similar to it. It only needs to keep the temperature and pressure conditions constant and start collecting Raman spectra after the sample reaches dissolution-crystallization equilibrium.

[0042] The advantages of the method provided in this embodiment are very obvious, mainly reflected in the following three aspects: First, it has high universality. This method is applicable to all substances with Raman vibration activity, and the vast majority of geological minerals and organic substances have characteristic Raman vibration peaks. Therefore, the applicable range of this method is very wide.

[0043] At the same time, it has high measurement accuracy. The appearance of Raman vibration peaks reflects the intrinsic molecular structure and composition of the sample, and is not affected by factors such as the sample size and geometry, temperature and pressure gradients. Therefore, interference from these external factors on the measurement accuracy can be avoided.

[0044] Furthermore, the experimental operation is simple. This method has no special or additional requirements for the DAC model and sample loading, and after setting the Raman spectroscopy parameters, the three-dimensional imaging data acquisition will run automatically. Compared with in-situ resistivity and sound velocity measurements, the experimental operation of this method is very simple.

[0045] (2) Method for in-situ determination of carbonate solubility in DAC: The limitations of the existing technology are mainly manifested in aspects such as complex experimental operations, low universality, and complex factors affecting accuracy. This embodiment provides a new method for in-situ determination of carbonate solubility in DAC, that is, using high-resolution Raman spectroscopy three-dimensional imaging technology to reconstruct the three-dimensional image of carbonate in high-temperature and high-pressure fluids and accurately calculate its volume. Combining the known bulk modulus, thermodynamic parameters or density of carbonate, the mass of carbonate under this temperature and pressure condition can be obtained. The difference between the mass of the dissolved carbonate and the initial mass of carbonate is the dissolved amount. This method does not require calibration of the standard curve, and the experimental operation is very simple; it is also not limited by factors such as changes in laboratory conditions, the performance of the Raman spectrometer, and the DAC device, and has high universality and test accuracy.

[0046] Calcite CaCO 3 is one of the most widely distributed and common carbonates on the earth's surface. Taking calcite as an example, the specific implementation process of this embodiment is described.

[0047] The first step is to characterize the initial calcite.

[0048] (1) Load calcite and deionized water into the DAC sample chamber, observe and focus under a Raman (WITec Alpha 300) microscope (objective lens Olympus 20×). Set the Raman spectroscopy three-dimensional imaging parameters: imaging area X range: 210 ; Y range: 140 ; Z range: 100 ; scanning step size: 2 ; laser power: 50 mW; single-spectrum integration time: 0.05 s. After setting, the instrument automatically collects Raman spectra and scans layer by layer. Reconstruct the three-dimensional stereoscopic image of the sample based on the above data to obtain its test volume . After volume calibration parameters ( Calibrate to obtain the volume of the initial calcite (where the calibration coefficient = 0.843965). .

[0049] (2) Density of carbonate under normal temperature and pressure = 2.711 g / cm 3 It is known that according to mass = volume × density (M = V × ), the mass of the initial carbonate sample is calculated = 2.069 . At the same time, the volume of the sample chamber and the density of water under normal temperature and pressure are known. Combining with the volume of the sample , the mass of the solvent water can be obtained .

[0050] Second step, determine the solubility of calcite under high temperature and pressure conditions

[0051] (1) Raise the temperature to °C, calibrate the pressure to at this time through calcite. When the sample reaches the dissolution-crystallization equilibrium, use the same method as above to obtain the Raman test volume and the accurate volume of calcite under this condition

[0052] (2) According to the isothermal compressibility and thermal expansion coefficient °C of calcite, obtain the density of calcite under this condition

[0053] Combine the volume to obtain its mass , and the difference from the initial mass is the dissolved amount . After unit conversion, the amount of substance of the dissolved carbonate is obtained , and the solubility of carbonate is obtained by combining with the mass of water .

[0054] The advantages of the method provided by this embodiment are mainly reflected in the following three aspects First, simple operation. The method provided by this embodiment does not require calibration of the standard curve, thus avoiding the error caused by the "non-standard" standard curve; at the same time, it greatly reduces the complexity and tediousness of the experimental operation

[0055] Second, high accuracy. The previous method for measuring the solubility of carbonate was to directly measure [CO 3 2- ​content. The method provided by this embodiment takes a different approach. By quantitatively studying the change in the volume of carbonate, the amount of dissolved substance is obtained, and then the solubility of the carbonate to be measured under the temperature and pressure conditions is obtained. The method does not require direct measurement of the Raman spectrum of the solution, thus avoiding the fitting errors caused by factors such as the peak shape changes of the solute [[CO 3 2- and the solvent H 2 O and the appearance of the Raman vibration peak of [HCO 3 - at high temperatures.

[0056] Third, wide universality. The present invention does not rely on the relative peak intensity of the Raman peak to obtain the solubility of carbonate, so it is not affected by the state of the Raman spectrometer and laboratory conditions. This method is applicable to any Raman instrument in any laboratory.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.​​

Claims

1. A method for in-situ determination of the volume and solubility of minerals in DAC, characterized in that: The method comprises: S11, loading the sample to be tested and the solvent into the DAC sample chamber, generating an initial three-dimensional stereoscopic image of the sample to be tested at room temperature and pressure by Raman spectroscopy three-dimensional imaging technology, and calculating the initial volume of the sample to be tested based on the initial three-dimensional stereoscopic image ; S12. After the temperature and pressure are raised to the target conditions and stabilized, a real-time three-dimensional image of the sample to be tested is generated through Raman spectroscopy three-dimensional imaging technology to calculate the volume of the sample to be tested under the target conditions. ; S13. Calculate the mass difference between the sample at room temperature and pressure and the target condition based on the volume compression coefficient and thermodynamic parameters of the sample to be tested, and calculate the solubility based on the mass difference and the solvent mass. .

2. The method according to claim 1, characterized in that The solvent is a deionized water solution.

3. The method according to claim 1, characterized in that A three-dimensional Raman image of the sample to be tested is generated by Raman spectroscopy three-dimensional imaging technology, specifically: under a Raman microscope, Raman spectroscopy three-dimensional imaging parameters are set, Raman spectroscopy data of the sample to be tested is collected, and a three-dimensional Raman image of the sample to be tested is reconstructed based on the collected Raman spectroscopy data.

4. The method according to claim 3, characterized in that The Raman spectrum three-dimensional imaging parameters include: imaging area size, scanning step length, single spectrum integration time, laser power and scanning times.

5. The method according to claim 1, characterized in that By combining the initial 3D stereo image and volume calibration parameters Calculate the initial volume of the sample to be tested , the calculation of volume calibration parameters specifically includes: The three-dimensional image of the sample to be tested is obtained by electronic computer tomography to calculate the scanning volume of the sample to be tested. ; The three-dimensional Raman spectrum of the sample to be tested is obtained by Raman spectroscopy three-dimensional imaging technology to calculate the test volume of the sample to be tested. ; The volume calibration parameters are calculated based on the scan volume and the test volume. The calculation formula is: 。 6. The method according to claim 5, characterized in that Calculate the volume of the sample under target conditions based on the initial volume and real-time 3D image , specifically including: Calculate the Raman test volume of the sample to be tested based on real-time 3D stereo images , According to the Raman test volume of the sample to be tested and volume calibration parameters Calculate the volume of the sample under target conditions as follows: 。 7. The method according to claim 1, characterized in that Calculate the solubility of the sample under target conditions based on the initial volume and real-time 3D images , specifically including: Based on the initial volume of the sample to be tested Its density at room temperature and pressure Calculate the initial mass of the sample to be tested , the calculation formula is: ； Based on the volume of the DAC sample chamber and the density of water at room temperature and pressure, combined with the initial volume of the sample to be tested, the mass of the solvent is calculated ; Calculate the mass of the sample under target conditions based on real-time 3D images, volume compression coefficients and thermodynamic parameters of the sample ; Calculate the dissolved amount of the sample to be tested After unit conversion, the amount of substance dissolved in the sample to be tested is obtained n , combined with the solvent mass, calculate the solubility of the sample under target conditions , the calculation formula is as follows: 。 8. The method according to claim 1, characterized in that The method is applicable to all Raman-active minerals and organic substances.

9. The method according to claim 8, characterized in that The method is applicable to carbonates, silicates, sulfates and phosphates.

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