A pegmatite high-purity quartz purification method and purity evaluation method

Abstract

The application discloses a pegmatite high-purity quartz purification method and a purity extraction evaluation method, wherein the purification method comprises the following steps: S1, selecting a quartz sample C from a pegmatite high-purity quartz sample collected from the field by means of naked eye observation, microscopic slice observation and whole rock analysis; S2, performing laser confocal Raman spectrum determination on the quartz sample C to obtain typical characteristic peak value data and lattice Al data of fluid inclusions in the quartz sample C, removing the quartz sample that does not meet the requirements based on the lattice Al data to obtain a quartz sample D; S3, performing fluid inclusion temperature measurement on the screened quartz sample D, and selecting a quartz sample E with a homogenization temperature less than 600 DEG C from the quartz sample D; and performing explosion on the quartz sample E to obtain a final purified product. The application also provides a purity extraction evaluation method for the pegmatite high-purity quartz. The application realizes purification of the pegmatite high-purity quartz and grading evaluation of the purified quartz.

Description

Technical Field

[0001] This invention belongs to the field of high-purity quartz purification technology, specifically relating to a method for purifying high-purity quartz from pegmatite and a method for evaluating the purity of the extracted material. Background Technology

[0002] With the rapid development of science and technology, high-purity quartz (SiO2 purity ≥ 99.998%) has become an irreplaceable key material in high-tech fields such as semiconductors, photovoltaics, and new energy. For example, high-purity quartz is mainly used as a core material for preparing high-end electronic components such as semiconductor chips, optical fiber communication devices, and solar cells. The purity of high-purity quartz will directly affect the performance of these high-end electronic components.

[0003] Impurities in high-purity quartz mainly originate from mineral lattice defects and fluid inclusions (gas-liquid and solid inclusions). Na in these inclusions... + K+, Li+, Ca 2+ Components such as CO2 can significantly reduce the electrical properties (such as dielectric loss) and optical transmittance of quartz.

[0004] Currently, there are five existing methods for quartz sand purification: microwave-ultrasonic purification, vacuum semi-melting-sand making purification, multi-stage separation-high-temperature atmosphere purification, flotation-magnetic separation combined purification, and high-temperature chlorination-alkali-acid purification. Microwave-ultrasonic purification and vacuum semi-melting-sand making purification can thoroughly remove inclusions, offering high efficiency in impurity removal, environmental optimization, and energy saving. However, they are characterized by complex equipment, extremely high energy consumption, high equipment investment and maintenance costs, and difficulty in process control. Multi-stage separation-high-temperature atmosphere purification suffers from a lengthy composite process, huge equipment investment, and risks associated with halogen treatment. Flotation-magnetic separation combined purification offers high efficiency in mineral separation, innovative equipment, and low energy consumption; however, it has drawbacks such as a low purity ceiling and high wastewater treatment pressure. High-temperature chlorination-alkali-acid combined purification offers extremely high purity, thorough removal of metallic impurities, and a mature and stable process. However, extreme conditions, such as 1600℃, require special kilns with high refractory material consumption, strong chlorine corrosiveness, and difficult exhaust gas treatment, posing safety and environmental risks. It is particularly important to note that these methods primarily focus on the purification and determination of quartz from chemical, mineral processing, and smelting perspectives, but they have high practical barriers to entry. This is because the quality of raw quartz samples is unstable; high-purity quartz sources are scarce, impurities are unevenly distributed across different locations within the same vein, and not all quartz from the same location meets the requirements for high purity. This is especially true for pegmatite-type quartz, which often develops throughout the entire pegmatite region (greater than 50 km²). 2 Within each structural zone (area). Therefore, adopting complex mineral processing techniques without first conducting basic geological specimen assessment and microscopic screening will significantly increase mineral processing costs.

[0005] In summary, the selection of a low-cost, rapid, simple, and effective determination method is urgently needed, providing important indicators and directions for geological prospecting. However, there is currently no high-precision purification method for high-purity quartz in pegmatite; moreover, existing technologies for evaluating and grading the purity of extracted quartz consider only one factor, resulting in unscientific and unreasonable evaluations. Summary of the Invention

[0006] In view of the above analysis, the embodiments of the present invention aim to provide a method for purifying high-purity quartz from pegmatite and a method for evaluating the extraction purity, so as to solve one or more of the above-mentioned problems existing in the prior art.

[0007] The objective of this invention is achieved as follows:

[0008] On the one hand, a method for purifying high-purity quartz from pegmatite is provided, comprising the following steps:

[0009] S1. Quartz sample C was selected from the high-purity quartz pegmatite samples collected in the field by means of visual observation, microscopic thin section observation and whole rock analysis.

[0010] S2. Perform laser confocal Raman spectroscopy on quartz sample C to obtain typical characteristic peak data and lattice Al data of fluid inclusions in quartz sample C. Based on the lattice Al data, quartz samples that do not meet the requirements are eliminated to obtain quartz sample D.

[0011] S3. Perform fluid inclusion temperature measurement on the selected quartz sample D to obtain the homogenization temperature of the fluid inclusions in quartz sample D; use quartz sample E with a homogenization temperature of less than 600℃ as the preliminary purification product of pegmatite high-purity quartz.

[0012] Furthermore, it also includes:

[0013] S4. The pre-purified product is subjected to bursting at a temperature greater than 600°C to obtain quartz sample F, which is the final purified product of pegmatite high-purity quartz.

[0014] Furthermore, step S1 also includes:

[0015] S11. Quartz sample A, which is milky white, grayish white, or white and has a greasy luster, is initially selected by visual inspection. Quartz sample A is then cut using a diamond wire saw or a precision cutting machine to prepare a double-sided polished thin slice with a thickness of <100μm. The thin slice is observed under a microscope to select quartz sample B. Quartz sample B meets the following condition: within the 50x magnification field of view of the microscope, the total area of ​​fluid inclusions within the visible area is not higher than 1 square millimeter.

[0016] S12. Whole-rock testing was performed on quartz sample B. Combined with XRD and LA-ICP-MS pre-screening of quartz samples with low impurities, quartz sample C was obtained.

[0017] Furthermore, in step S1, the selected quartz sample C satisfies the following condition:

[0018] The SiO2 content of quartz is Al < 50 ppm, Fe < 5 ppm.

[0019] Furthermore, in S12, when conducting whole-rock testing, quartz sample B is crushed into powder of 60-80 mesh, and the powder is then subjected to whole-rock testing.

[0020] Further, in step S3, the fluid inclusions to be measured in quartz sample D are first identified by cathodic emission and ordinary microscopy, and the fluid inclusions in quartz sample D are subjected to microscopic thermometry using a hot and cold stage to obtain the temperature measurement data of the fluid inclusions in quartz sample D.

[0021] On the other hand, a method for evaluating the purity of high-purity quartz extracted from pegmatite is also provided, for evaluating the purity of the obtained quartz sample F; the evaluation method includes the following steps:

[0022] S5. Perform gas phase analysis on the fluid inclusions in quartz sample F to obtain gas phase analysis data;

[0023] S6. Perform liquid phase analysis on the fluid inclusions in quartz sample F to obtain liquid phase analysis data;

[0024] S7. Based on experimentally determined gas-phase and liquid-phase measurement data, obtain the impurity content R and Ca in the fluid inclusions. 2+ Li + Na + +K + Content, based on the impurity content R and Ca in the fluid inclusions. 2+ Li + Na + +K + The content was determined to obtain the purification grade of high-purity quartz from pegmatite.

[0025] Further, in step S7, the impurity content R in the fluid inclusion is calculated according to the following formula:

[0026]

[0027] In the above formula, m 流体 m is the mass of a unit volume of fluid inclusion; 杂质 This represents the mass of impurities per unit volume of fluid inclusion.

[0028] Furthermore, the purification grade results of the pegmatite high-purity quartz include:

[0029] Category I: 8 ≤ R < 26 ppm, and 2 ≤ Ca 2+ <5ppm, 1≤Li + <5ppm, 5≤Na + +K + <16ppm;

[0030] Category II: 1 ≤ R < 8 ppm, and 0.3 ≤ Ca 2+ <2ppm, 0.2≤Li + <1ppm, 0.5≤Na + +K + <

[0031] 5ppm;

[0032] Category III: 0 < R < 1 ppm, and 0 < Ca 2+ <0.3ppm, 0<Li + <0.2ppm, 0<Na + +K +

[0033] <0.5ppm.

[0034] Furthermore, in step S7, based on the volume, number, and density of fluid inclusions in the quartz sample F, the mass m of the fluid inclusions per unit volume is obtained. 流体 The mass m of impurities per unit volume of fluid inclusions in quartz sample F was obtained by gas-liquid phase composition determination. 杂质 .

[0035] Further, step S5 includes:

[0036] S51. The granular powder of quartz sample F has been subjected to ultra-clean cleaning, and the preliminary pretreatment has been completed.

[0037] S52. The granular powder of the ultra-cleaned quartz sample F is purged at 200℃ for 15 min to complete the secondary pretreatment.

[0038] S53. Perform gas chromatography on the granular powder of quartz sample F after secondary pretreatment to obtain the gas phase content data of fluid inclusions.

[0039] Further, step S6 includes:

[0040] S61. Use one of the following methods to pretreat the quartz sample F: high-temperature annealing, chemical dissolution, or physical separation.

[0041] S62. The pretreated quartz sample F particles are subjected to ultrasonic extraction to obtain an extract containing fluid inclusions; the extract is then subjected to ion chromatography to obtain liquid phase measurement data, including: Li + Na + K + Ca 2+ Mg 2+ .

[0042] Compared with existing technologies, the present invention provides a method for purifying high-purity quartz from pegmatite and a method for evaluating the extraction purity. This method combines petrography, microthermometry, laser confocal Raman spectroscopy, gas chromatography, liquid chromatography and mass spectrometry (ICP-AES) tandem techniques to analyze the gas and liquid phase components (H2O, CO2, Na) of inclusions. + K+, Li+, Ca 2+ Multi-scale analysis was performed on the pegmatite, and three methods were employed to effectively remove secondary fluid inclusions: high-temperature annealing (near-melting-point isothermal treatment under an inert atmosphere), selective acid etching (HF vapor or aqua regia), and physical separation. Based on this, further purification of the pegmatite high-purity quartz was achieved by subjecting the pre-purified product to 600℃-800℃ bursting. This invention comprehensively utilizes basic geological observation and mature gas-liquid chromatography techniques. The method is rapid, simple, efficient, low-cost, and environmentally friendly, providing important indicators for geological prospecting.

[0043] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the description of the embodiments or 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 those skilled in the art, other drawings can be obtained based on these drawings.

[0045] Figure 1 These are some pegmatite quartz samples selected in the embodiments of the present invention;

[0046] Figure 2 The pegmatite quartz thin sections prepared in the embodiments of the present invention and the typical fluid inclusion characteristics under a microscope;

[0047] Figure 3The embodiments of the present invention include microscopic images of quartz sample D under cathodic illumination and ordinary microscopes; wherein, image a is a microscopic image of quartz sample D under cathodic illumination conditions; images b and c are fluid inclusion feature images of quartz sample D under ordinary microscopes.

[0048] Figure 4 A schematic diagram of the operation flow of the method for purifying high-purity quartz from pegmatite provided by the present invention;

[0049] Figure 5 This is a schematic diagram of the operation process for evaluating the purity of high-purity quartz extraction from pegmatite provided by the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] To facilitate understanding of the embodiments of this application, further explanation and description will be provided below with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of this application. In the drawings, the dimensions and relative dimensions of components may be exaggerated for clarity and / or descriptive purposes. When exemplary embodiments can be implemented differently, a specific process sequence may be performed in a different order than that described. For example, two consecutively described processes may be performed substantially simultaneously or in the reverse order of their description. Furthermore, the same reference numerals denote the same components.

[0052] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms “a” and “the” are intended to include the plural forms as well. Furthermore, when the terms “comprising” and / or “including” and variations thereof are used in this specification, it indicates the presence of the stated features, integrals, steps, operations, parts, components, and / or groups thereof, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, parts, components, and / or groups thereof. It should also be noted that, as used herein, the terms “substantially,” “about,” and other similar terms are used as approximate terms rather than as terms of degree, thus explaining the inherent biases in measurements, calculated values, and / or provided values ​​that would be recognized by one of ordinary skill in the art.

[0053] Example 1

[0054] A specific embodiment of the present invention, such as Figures 1 to 4 As shown, a method for purifying high-purity quartz from pegmatite is disclosed, including the following steps S1-S3:

[0055] S1. Quartz sample C was selected from the high-purity quartz samples of pegmatite collected in the field through visual observation, microscopic thin section observation, and whole-rock analysis.

[0056] S11. From the collected high-purity quartz pegmatite samples, quartz sample A that meets the requirements is initially selected by visual inspection. Quartz thin sections are prepared and observed under a microscope. The quartz sample selected is quartz sample B. Quartz sample B meets the following conditions: within the 50x magnification field of view of the microscope, the total area of ​​fluid inclusions in the visible area is not higher than 1 square millimeter.

[0057] The steps for preparing thin sections from bulk samples are as follows: Quartz minerals from different zones within the pegmatite are visually selected. Quartz samples that are milky white, grayish white, or white in color and have a greasy luster are chosen as representative raw quartz samples. Figure 1 As shown; using a diamond wire saw or precision cutting machine, the blocky quartz sample A selected by the naked eye is cut to prepare a double-sided polished sheet with a thickness of <100μm, as shown. Figure 2 As shown, this is to prevent the inclusion from breaking.

[0058] Specific steps for observing thin sections under a microscope: The microscope magnification should be between 30 and 300; the microscope light source should be a general light source or a polarized light source; the image acquisition method includes: in the field of view, move the slide in sequence from left to right and then from top to bottom, moving it 3-6 mm each time to ensure that there are no duplicate particles in the photos, and take 15-20 photos in which the distribution of quartz fluid inclusions can be clearly observed.

[0059] S12. Further, whole-rock testing was performed on quartz sample B. Based on the whole-rock test results, quartz sample C was obtained through further screening. That is, quartz sample C was obtained by simultaneously pre-screening low-impurity quartz samples using both XRD (XRD diffractometer) and LA-ICP-MS (laser-inductively coupled plasma mass spectrometry). The remaining quartz sample C met the following condition: the SiO2 content of the quartz was [missing information]. Al < 50 ppm, Fe < 5 ppm.

[0060] In step S12, during the whole-rock test, quartz sample B needs to be crushed into powder, and the powder is then subjected to the whole-rock test. Specifically, the selected quartz sample B is crushed, wet-milled, filtered, concentrated, and dried, and the powder sample is ground to a mesh size of 60 to 80.

[0061] After removing the quartz samples that do not meet the requirements from quartz sample B, the powder samples that meet the requirements, namely the powder from quartz sample C, are retained for use in subsequent steps S2-S3.

[0062] S2. Perform laser confocal Raman spectroscopy on quartz sample C to obtain typical characteristic peak data and lattice Al data of fluid inclusions in quartz sample C. Based on the lattice Al data, quartz samples that do not meet the requirements are eliminated to obtain quartz sample D.

[0063] In-situ analysis of a single fluid inclusion in quartz sample C was performed using laser confocal Raman spectroscopy, yielding typical characteristic peak data and the Al-OH defect peak (3580 cm⁻¹). -1 Directly remove Al with lattice 3 + The contaminated quartz sample was used to obtain quartz sample D.

[0064] S3. Perform fluid inclusion temperature measurement on the selected quartz sample D to obtain the homogenization temperature of the fluid inclusions in quartz sample D; select quartz sample E with a homogenization temperature of less than 600℃ from quartz sample D, and use quartz sample E with a homogenization temperature of less than 600℃ as the preliminary purification product of pegmatite high-purity quartz.

[0065] Specifically, the fluid inclusions to be measured in quartz sample D are first identified using cathodoluminescence and ordinary microscopy. Then, a hot-cold stage is used to perform microthermometry on the fluid inclusions in quartz sample D, obtaining the temperature data of the fluid inclusions in quartz sample D; for example, according to... Figure 3 Figure a shows a microscopic image of quartz sample D under cathodic luminescence conditions, used to determine the region containing the fluid inclusions to be measured in quartz sample D. Figure 3 The inclusions in figures b and c; then, for Figure 3 Microthermography was performed on the fluid inclusions of quartz sample D in Figures b and c. Based on the thermometric data of the fluid inclusions in quartz sample D, quartz samples with a homogenization temperature greater than 600℃ were removed, resulting in quartz sample E.

[0066] During step S3, the type of fluid inclusions in quartz sample E can be determined simultaneously. Based on the different types of fluid inclusions in quartz sample E, the salinity and density data of the fluid inclusions in quartz sample E are obtained, preparing for subsequent purity evaluation. Typical characteristic peak data for determining the type of fluid inclusions in quartz sample E include H2O (3400 cm⁻¹). -1 ), CO2 (1285 / 1388cm) -1 Peak data, based on H2O (3400 cm⁻¹) in fluid inclusions in quartz sample E. -1 ), CO2 (1285 / 1388cm) -1The peak value is used to determine the type of fluid inclusions in quartz sample E, which includes two types: low-salinity CO2-containing fluid inclusions and high-salinity CO2-free fluid inclusions.

[0067] In step S3, when performing microthermometry on the fluid inclusions in quartz sample D using a hot and cold stage, the freezing point (-100 to 0°C) is determined by freezing, and the salinity (0 to 23 wt% NaCl eq) is calculated. All the test data obtained for quartz sample D during this process include the freezing point data required for calculating the salinity of quartz sample E. Furthermore, the density ρ (g / cm³) of different types of fluid inclusions in quartz sample E is obtained based on the type of fluid inclusion. 3 ).

[0068] Based on the fluid inclusion temperature data in step S3, in quartz sample E with a homogenization temperature less than 600℃, the homogenization temperature of high-salinity fluid inclusions without CO2 is between 500 and 600℃, and the homogenization temperature of low-salinity fluid inclusions containing CO2 is between 200 and 300℃, providing a reference for burst temperature in the subsequent step S4.

[0069] S4. The obtained preliminary purified product is subjected to explosion to remove impurities in the inclusions of quartz sample E, resulting in quartz sample F. Quartz sample F is the final purified product of pegmatite high-purity quartz.

[0070] Based on the fluid inclusion temperature data in step S3, the homogenization temperature of high-salinity CO2-free fluid inclusions in quartz sample E is between 500 and 600°C, while the homogenization temperature of low-salinity CO2-containing fluid inclusions is between 200 and 300°C. Therefore, the bursting temperature T used in step S4 is greater than 600°C, and the bursting time t is greater than 10 minutes; for example, the bursting temperature T is 600°C-800°C, and the bursting time t is 15-30 minutes.

[0071] This embodiment also provides a method for evaluating the purity of high-purity quartz extracted from pegmatite, which is used to evaluate the purity of quartz sample F obtained in step S4.

[0072] Reference Figure 5 The method for evaluating the purity of high-purity quartz extraction from pegmatite in this embodiment includes steps S5-S7:

[0073] S5. Perform gas phase analysis on the fluid inclusions in quartz sample F to obtain gas phase analysis data.

[0074] S51. The granular powder of quartz sample F has been subjected to ultra-clean cleaning, and the preliminary pretreatment has been completed.

[0075] Before conducting gas phase testing, the quartz sample F needs to be ultra-cleaned by ultrasonic cleaning with acetone, ethanol, and ultrapure water for 10 minutes in sequence to remove contaminants from the surface of the quartz sample F.

[0076] S52. Perform a secondary pretreatment on the granular powder of the quartz sample F after ultra-clean cleaning by purging at 200℃ for 15 min.

[0077] Because the quartz sample F, after ultra-clean cleaning, still adsorbed small amounts of water and air, affecting the determination of H2, O2, N2, CO, CO2, and H2O, a purging process was performed at 200℃ for 15 minutes, based on the temperature measurement data in step S3, to further eliminate the interference of fluid inclusions and powder surface impurities with homogenization temperatures of 0–200℃ on the experimental results. Once the air and H2O peaks were observed to have completely eluted in the TCD channel of the chromatography workstation, it could be considered that the adsorbed water and air had been completely removed.

[0078] S53. The granular powder of quartz sample F after secondary pretreatment is tested. The gas phase content of fluid inclusions is determined by gas chromatography, and the content data of H2, CO2, H2O, CH4, C2H2, C2H6 and C3H8 in the fluid inclusions are obtained.

[0079] S6. Perform liquid phase analysis on the fluid inclusions in quartz sample F to obtain liquid phase analysis data.

[0080] S61. Pretreatment of quartz sample F shall be performed using one of the following methods: high-temperature annealing, chemical dissolution, or physical separation. Details are as follows:

[0081] ① High-temperature annealing method.

[0082] In an inert atmosphere (such as Ar), the granular powder of quartz sample F is heated to 50–200°C below the mineral melting point and held at that temperature for 24–48 hours. This causes the internal pressure of the fluid inclusions to exceed the mineral strength, resulting in bursting and release of the contents. The remaining cavity is sealed by the mineral's self-healing mechanism, thus completing the sample pretreatment.

[0083] ② Chemical dissolution method. Selective acid treatment can be used, such as HF vapor etching or aqua regia treatment. Details are as follows:

[0084] HF vapor etching procedure: Place the granular powder of quartz sample F in a sealed container, introduce 40% HF vapor into the sealed container, maintain the temperature at 60℃ for 2 hours, dissolve the matrix around the inclusions, retain the cavity, and complete the sample pretreatment.

[0085] Aqua regia treatment steps: Immerse the granular powder of quartz sample F in a mixed acid of HCl:HNO3 with a volume ratio of 3:1 and a temperature of 60°C. After immersing in the mixed acid for 6 hours, place it on a heating plate at 200°C for 3 hours to dissolve the metal inclusions. Then wash with ultrapure water until the conductivity of the ultrapure water is reached.

[0086] ③ Physical separation method

[0087] High-pressure hydraulic crushing was used: the granular powder of quartz sample F was mixed with ultrapure water and crushed in a cyclic manner under a pressure of 200 MPa to release the contents of the fluid inclusions and complete the sample pretreatment.

[0088] S62. Perform liquid phase fluid inclusion determination on the pretreated quartz sample F to obtain liquid phase measurement data.

[0089] S621. The quartz sample F particles that have completed bursting are subjected to ultrasonic extraction to obtain an extract sample containing fluid inclusions. Specifically, ultrasonic extraction is performed N times, 10 mL each time. From the N-1th extraction, almost no ions are detected, and from the Nth extraction, no ions are detected at all, indicating that all fluid inclusions have entered the extract, thus obtaining an extract sample containing fluid inclusions.

[0090] S622. Perform ion chromatography on the extract sample to obtain liquid phase measurement data, including: Li + Na + K + Mg 2+ Ca 2+ F - Cl - ,Br - NO 2- NO 3- SO4 2- Anions and cations.

[0091] S7. Based on experimentally determined gas-phase and liquid-phase measurement data, obtain the impurity content R and Ca in the fluid inclusions. 2+ Li + Na + +K + Content, based on the impurity content R and Ca in the fluid inclusions. 2+ Li + Na + +K + The content was used to obtain the purification grade of high-purity quartz in pegmatite, and the purification grades of high-purity quartz in pegmatite were specifically divided into Grade I, Grade II and Grade III.

[0092] S71. The mass percentage of impurities contained in a unit area of ​​fluid inclusion is defined as the impurity content R in the fluid inclusion. The impurity content R in the fluid inclusion is calculated according to the following formula:

[0093]

[0094] In the above formula, m 流体 m is the mass of a unit volume of fluid inclusion; 杂质 The mass of impurities per unit volume of fluid inclusion;

[0095] S711. Based on the volume, number, and density of fluid inclusions in quartz sample F, obtain the mass m of fluid inclusions per unit volume. 流体 .

[0096] The volume and number of fluid inclusions in quartz sample F can be calculated using the following method:

[0097] Method 1: Microscopic observation. The shape, size and distribution of fluid inclusions are observed using a petrographic microscope, and the volume of a single inclusion and the number per unit area are recorded.

[0098] Method 2: 3D reconstruction. The 3D volume of the inclusion is estimated using Raman imaging or gravity method, and the total volume of the inclusion is calculated by combining the distribution density.

[0099] The mass m of a fluid inclusion per unit volume is calculated using the following steps. 流体 :

[0100] The volume of the fluid inclusion is V = h × S, where h is the cross-sectional height. The value of h can be 1. Then the mass of a unit volume of fluid inclusion is m_. 流体 for:

[0101] m 流体 =ρV=ρhS=ρS.

[0102] In the formula, m_ 流体 ρ is the mass of a fluid inclusion per unit volume; ρ is the density of the fluid inclusion; S is the total area of ​​a linear aggregate of multiple fluid inclusions within a single field of view.

[0103] The ρ of a single fluid inclusion can be obtained from fluid inclusion microthermography, see step S4 for details; the steps to solve for the total area of ​​a linear aggregate of multiple fluid inclusions within a single field of view are as follows:

[0104] Assuming that the fluid inclusions are approximately circular, then a linear collection of fluid inclusions can be understood as a combination of several densely arranged circular fluid inclusions.

[0105] Suppose there exist m linear wrapper combinations, numbered 1, 2, i, ..., m respectively.

[0106] Analyze the linear inclusion combination numbered i, with the linear direction as the x-axis, and denote the number of rows of the linear inclusion combination as n. (i) (x), the diameter of a single fluid inclusion is f (i) (x), the length of a single linear wrapper assembly is l (i) .

[0107] therefore:

[0108] The area of ​​a single linear inclusion body assembly is:

[0109] The total area S of the linear aggregate of multiple fluid inclusions is:

[0110]

[0111] S712. Obtain the mass m of impurities per unit volume of fluid inclusions in quartz sample F by gas-liquid phase composition determination. 杂质 Wherein, the mass m of a unit volume of fluid inclusion... 流体 The weight includes water, impurities in fluid inclusions, and gaseous components.

[0112] S713, m 杂质 and m_ 流体 Substitute into the formula In this process, the formula for calculating the impurity content R in fluid inclusions is:

[0113]

[0114] S72. Based on the impurity content R in the fluid inclusions and the Ca in the liquid phase measurement data... 2+ Li + Na + +K + Based on content, the purification grades of high-purity quartz from pegmatite are divided into Grade I, Grade II, and Grade III, corresponding to high-purity quartz, ultra-high-purity quartz, and super-pure quartz proposed by Harben, respectively. Details are as follows:

[0115] Category I: 8 ≤ R < 26 ppm, and 2 ≤ Ca 2+ <5ppm, 1≤Li + <5ppm, 5≤Na + +K + <16ppm.

[0116] Category II: 1 ≤ R < 8 ppm, and 0.3 ≤ Ca 2+ <2ppm, 0.2≤Li + <1ppm, 0.5≤Na + +K+ <

[0117] 5ppm.

[0118] Category III: 0 < R < 1 ppm, and 0 < Ca 2+ <0.3ppm, 0<Li + <0.2ppm, 0<Na + +K +

[0119] <0.5ppm.

[0120] After testing and purification, the SiO2 content of the pegmatite-type high-purity quartz product reached 99.9983%, and the product purity grade reached 4N8.

[0121] According to Table 1 of the experimental results, the quartz sample with sample number 3 has a purification level of III, the quartz samples with sample numbers 2-10 have a purification level of II, and the quartz sample with sample number 11 has a purification level of III.

[0122] Table 1 Liquid and gaseous components of fluid inclusions

[0123]

[0124] Compared with existing technologies, the method for purifying high-purity quartz from pegmatite and the method for evaluating the purity of high-purity quartz extraction from pegmatite provided in this embodiment have the following beneficial effects:

[0125] (1) This application combines petrography, microthermography, laser confocal Raman spectroscopy, gas chromatography, liquid chromatography and mass spectrometry (ICP-AES) tandem techniques to analyze the gas and liquid phase components (H2O, CO2, Na) of the inclusions. + K+, Li+, Ca 2+ Multi-scale analysis was performed on the pegmatite, and three methods were employed to effectively remove secondary fluid inclusions: high-temperature annealing (near-melting-point isothermal treatment under an inert atmosphere), selective acid etching (HF vapor or aqua regia), and physical separation. Based on this, further purification of the pegmatite high-purity quartz was achieved by subjecting the pre-purified product to explosive cracking at 600-800℃. This invention relates to basic geological observation and mature gas-liquid chromatography methods. The methods are rapid, simple, efficient, low-cost, and environmentally friendly, providing important indicators for geological prospecting.

[0126] (2) By observing geological specimens and in situ under a microscope, fluid inclusions can be accurately located and the types of fluid inclusions and the distribution patterns of impurities can be identified. Furthermore, by controlling the specific bursting temperature of fluid inclusions, impurities in inclusions can be removed in a targeted manner. Impurities can be reduced to the ppb level through a physical-chemical synergistic method, which helps to improve the purification accuracy of high-purity quartz.

[0127] (3) The quartz extraction purity of this application is ≥99.999%, with virtually no inclusion residue. The technical solution of this application can minimize the influence of fluid inclusions in high-purity quartz, meeting the standards for semiconductor-grade (5N) and photovoltaic-grade (4N8) quartz sand.

[0128] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for the purification of high purity quartz from pegmatite, characterized by, It comprises the following steps: S1, selecting a quartz sample C from a pegmatite high-purity quartz sample collected in the field by naked eye observation, microscopic thin section observation and whole rock analysis in turn; S2, performing laser confocal Raman spectrum measurement on the quartz sample C to obtain typical characteristic peak data and lattice Al data of fluid inclusions in the quartz sample C, removing the quartz sample that does not meet the requirements based on the lattice Al data to obtain a quartz sample D; S3, performing fluid inclusion temperature measurement on the screened quartz sample D to obtain the homogenization temperature of the fluid inclusions in the quartz sample D; taking a quartz sample E with a homogenization temperature less than 600 DEG C as a preliminary purification product of the pegmatite high-purity quartz; S4, performing explosion on the preliminary purification product at an explosion temperature greater than 600 DEG C to obtain a quartz sample F, which is the final purification product of the pegmatite high-purity quartz; In the step S1, the selected quartz sample C satisfies the following conditions: the SiO2 content of the quartz is 99.5% to 99.9%, the Al content is less than 50 ppm, the Fe content is less than 5 ppm, and the Ti content is less than 5 ppm. Al < 50 ppm, Fe < 5 ppm; In step S3, the fluid inclusions to be measured in the quartz sample D are determined by cathodoluminescence and ordinary microscopy, and micro-temperature measurement is performed on the fluid inclusions in the quartz sample D using a cooling and heating table to obtain the temperature measurement data of the fluid inclusions in the quartz sample D.

2. The pegmatite high purity quartz purification method according to claim 1, characterized by, Step S1 further comprises: S11, preliminarily selecting a quartz sample A with a color of ivory, off-white or white and having a greasy luster by naked eye, cutting the quartz sample A using a diamond wire saw or a precision cutting machine to prepare a <100 μm thick double-side polished thin section, and observing the thin section under a microscope to select a quartz sample B, which satisfies the following conditions: the total area of pre-inclusion fluid inclusions in the 50 times magnification field of view of the microscope is not higher than 1 square millimeter; S12, performing whole rock test on the quartz sample B to obtain the quartz sample C by combining XRD and LA-ICP-MS to pre-screen the quartz sample with low impurities.

3. The pegmatite high purity quartz purification method according to claim 2, characterized by, In S12, the quartz sample B is crushed into a 60 mesh-80 mesh powder during the whole rock test, and the powder is subjected to the whole rock test.

4. A method for evaluating the purity of pegmatitic high-purity quartz extraction, characterized by, The evaluation method comprises the following steps: S5, performing gas phase measurement on the fluid inclusions in the quartz sample F to obtain gas phase measurement data; S6, performing liquid phase measurement on the fluid inclusions in the quartz sample F to obtain liquid phase measurement data; In step S7, the impurity content R in the fluid inclusions is calculated according to the following formula: S7, based on the experimental determination of gas phase determination data and liquid phase determination data, obtain the impurity content R and Ca 2+ , Li + , Na + +K + content in the fluid inclusion, according to the impurity content R and Ca 2+ , Li + , Na + +K + content in the fluid inclusion, obtain the pegmatite high-purity quartz purification grade result.

5. The pegmatite high purity quartz extraction purity evaluation method according to claim 4, characterized by, The pegmatite high-purity quartz purification grade result comprises: In the above formula, m 流体 is the mass of the fluid inclusion per unit volume; m 杂质 is the mass of the impurities in the fluid inclusion per unit volume.

6. The pegmatite high purity quartz extraction purity evaluation method according to claim 5, characterized by, Step S6 comprises: Class I: 8 < R < 26 ppm, and 2 < Ca 2+ < 5 ppm, 1 < Li + < 5 ppm, 5 < Na + + K + < 16 ppm; Class II: 1 < R < 8 ppm, and 0.3 < Ca 2+ < 2 ppm, 0.2 < Li + < 1 ppm, 0.5 < Na + + K + < 5 ppm; Class III: 0 < R < 1 ppm, and 0 < Ca 2+ <0.3 ppm, 0 < Li + <0.2 ppm, 0 < Na + + K + <0.5 ppm.

7. The pegmatite high purity quartz extraction purity evaluation method according to claim 5, characterized by, In step S7, the mass m of the fluid inclusions per unit volume is obtained based on the volume, number, and density of the fluid inclusions in the quartz sample F 流体 ; the mass m of the impurities in the fluid inclusions per unit volume in the quartz sample F is obtained by a method of gas-liquid phase component determination 杂质 .

8. The pegmatite high purity quartz extraction purity evaluation method according to claim 7, characterized by, S61, performing pretreatment on the quartz sample F by using one of a high-temperature annealing method, a chemical dissolution method or a physical separation method; ​ S62, ultrasonic extraction is performed on the quartz sample F particle powder after the pretreatment, to obtain an extracted liquid sample containing fluid inclusions; ion chromatography is performed on the extracted liquid sample, to obtain liquid phase measurement data, including: Li + , Na + , K + , Ca 2+ , Mg 2+ .

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