Method for analyzing mineral components in deep sea polymetallic sediments

Abstract

The invention relates to the technical field of geological analysis and material characterization, and discloses a method for analyzing mineral components in deep sea polymetallic sediments. The invention provides the application of the back-mounted sample preparation in analysis of mineral components in deep sea multi-metal sediments, so that the preferred orientation effect caused by directional arrangement is effectively inhibited, and the authenticity of diffraction intensity information is guaranteed; according to the component analysis method, high-power X-ray excitation and slow scanning are adopted, diffraction signals of weak crystal phases and trace minerals are enhanced, it is ensured that spectrum information is complete, the signal-to-noise ratio is high, and the problems that a conventional method is weak in signal and prone to omission are solved; reliable identification and semi-quantitative calculation of the complex mineral composition are achieved through the matching principle of the peak position, the intensity and the geological background and the relative percentage content calculation formula. The method is not only suitable for ocean polymetallic nodules, but also can be popularized to similar complex samples such as cobalt-rich crusts, polymetallic ooze and the like, and provides a firm and reliable analysis technical support for deep sea mineral resource research and cause judgment.

Description

Technical Field

[0001] This invention relates to the field of geological analysis and materials characterization technology, and in particular to a method for analyzing mineral composition in deep-sea polymetallic sediments. Background Technology

[0002] Polymetallic nodules and other deep-sea polymetallic sediments are mineral aggregates formed in the deep-sea environment, possessing significant resource value and scientific importance. Their study involves the interdisciplinary integration of earth science, resource science, and environmental science, and has a profound impact on revealing the evolutionary laws of the Earth system, assessing the potential of deep-sea mineral resources, and understanding global environmental change. Accurate identification and quantitative analysis of the mineral composition in deep-sea polymetallic sediments are crucial foundations for research on their genetic mechanisms, mineralization environments, resource evaluation, and subsequent utilization. Currently, this field primarily relies on X-ray diffraction (XRD) technology for qualitative and semi-quantitative analysis of mineral composition. This method identifies phases by recognizing diffraction patterns generated by the mineral crystal structure and calculates the relative mineral content based on diffraction peak intensity information.

[0003] However, existing conventional XRD analysis methods still have many technical limitations in practical applications, directly affecting the accuracy and reliability of the analytical results. Firstly, in the sample preparation stage, current techniques generally employ a positive pressure method, where powdered samples are directly filled into the grooves of a standard glass sample holder and flattened. This method easily leads to directional alignment of platy, columnar, or acicular minerals during the pressing process, triggering a "preferred orientation" effect. This causes abnormal enhancement or weakening of diffraction peaks on certain crystal planes, distorting the relative intensity information of diffraction peaks for each mineral phase and severely affecting the accuracy of semi-quantitative calculations. Secondly, regarding instrument detection conditions, existing techniques often use relatively low X-ray power (typically below 5kW). For mineral phases with poor crystallinity or low content, this may be insufficient to excite a sufficiently strong diffraction signal, leading to weakened, broadened, or even submerged characteristic peaks by background noise. This not only affects the identification of mineral species but also increases the error in subsequent peak area fitting and content calculation. In addition, since deep-sea polymetallic sediments often contain a variety of layered minerals (such as barium magnesium manganese ore and hydrous manganese ore) as well as associated silicate and phosphate minerals, their diffraction peaks often overlap or interfere with each other. When the signal is weak, it is even more difficult to accurately resolve and assign them, which can easily lead to omissions or misjudgments in mineral characterization. Summary of the Invention

[0004] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of the present invention is to provide the application of back-mounted sample preparation in mineral composition analysis of deep-sea polymetallic sediments.

[0005] The second objective of this invention is to provide a method for analyzing the composition of minerals in deep-sea polymetallic sediments.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides the application of back-mounted sample preparation in mineral composition analysis of deep-sea polymetallic sediments.

[0008] In some embodiments of the present invention, the deep-sea polymetallic sediment is selected from one of the following: oceanic polymetallic nodules, deep-sea cobalt-rich crusts, and deep-sea polymetallic mud.

[0009] In some embodiments of the present invention, the back-mounted sample preparation method includes the use of a hollow sample holder; the material of the hollow sample holder is selected from metals or non-metals with low atomic numbers, including but not limited to aluminum, magnesium, glass and acrylic.

[0010] Specifically, aluminum, magnesium, glass, and acrylic all have low atomic numbers and low fluorescence scattering. They do not produce detectable interfering fluorescence within the scanning range (5°-75°, 2θ), and hollow sample holders do not produce their own X-ray diffraction peaks. Compared to aluminum (atomic number Z=13), glass hollow sample holders produce better diffraction results, but are not robust enough. Therefore, this invention preferably uses aluminum hollow sample holders to obtain interference-free pure diffraction patterns.

[0011] In some embodiments of the present invention, the bottom surface of the hollow portion is a planar structure.

[0012] A second aspect of the present invention provides a method for mineral composition analysis in deep-sea polymetallic sediments, comprising the following steps: S1. Collect deep-sea polymetallic sediments to be tested and prepare samples using the back-loading method; S2. Perform X-ray diffraction tests on the prepared sample to obtain the X-ray diffraction pattern of the sample. S3. By analyzing the X-ray diffraction pattern obtained in step S2, information on the mineral composition of deep-sea polymetallic sediments is obtained.

[0013] In some embodiments of the present invention, the deep-sea polymetallic sediment is selected from one of the following: oceanic polymetallic nodules, deep-sea cobalt-rich crusts, and deep-sea polymetallic mud.

[0014] In some preferred embodiments of the present invention, the deep-sea polymetallic sediment is an oceanic polymetallic nodule.

[0015] In some embodiments of the present invention, in step S1, the deep-sea polymetallic sediment to be tested undergoes pretreatment before sample preparation using the back-mount method. The pretreatment includes: air-drying the deep-sea polymetallic sediment naturally, grinding it with an agate mortar or ball mill, and then sieving it. The sieved powder is then mixed evenly for later use.

[0016] In some embodiments of the present invention, in step S1, the particle size of the deep-sea polymetallic sediment to be tested is less than 200 mesh.

[0017] In some preferred embodiments of the present invention, in step S1, the particle size of the deep-sea polymetallic sediment to be tested is 200-1500 mesh.

[0018] In some embodiments of the present invention, step S1, specifically includes the following operations: The hollow sample holder is fixed onto the substrate to form a filling chamber; The powder of the deep-sea polymetallic sediment to be tested is evenly and loosely sprinkled into the filling chamber. The sample powder is gently tapped around the filling chamber to allow it to settle and compact naturally. Excess powder is then gently scraped and removed. After sealing, the hollow sample holder and the substrate are rotated 180° together to complete the sample preparation.

[0019] In some embodiments of the present invention, the hollow sample holder is made of aluminum, the bottom surface of the hollow part is a planar structure, and the dimensions of the hollow part are (20-25)mm×(20-25)mm×(2-3)mm.

[0020] In some embodiments of the present invention, the substrate has a non-smooth surface to promote free mineral alignment and prevent preferred orientation, including but not limited to frosted glass plates.

[0021] In some embodiments of the invention, the leveling process includes using a glass slide.

[0022] In some embodiments of the invention, the cap includes sealing the filling chamber with tape.

[0023] Specifically, the back-mounted sample preparation system overcomes the inherent defects of the traditional positive pressure method, providing a reliable guarantee for subsequent high-precision X-ray diffraction testing. Specifically, it is reflected in: (1) Effectively suppressing preferred orientation: By uniformly and loosely spreading the sample on the back, rather than pressing it on the front, the sample powder is arranged in a natural and random direction, which significantly disrupts the orientation of platy, columnar and needle-like minerals, making the measured diffraction intensity more realistically reflect the mineral content, and fundamentally ensuring the accuracy of semi-quantitative calculation; (2) Ensuring sample consistency and comparability: Using a standard-sized aluminum hollow sample holder, combined with the leveling step, ensures that the filling amount, thickness and surface flatness of each sample preparation are highly consistent, laying the foundation for data comparison of different samples or repeated experiments; (3) Avoiding external signal interference: Using an aluminum sample holder (instead of an iron or steel frame) effectively avoids the interference of the sample signal by the fluorescence scattering of the sample preparation instrument itself. The hollow structure avoids the influence of the X-ray diffraction peak of the sample holder itself, thereby obtaining a purer diffraction pattern. (4) Stable operation and strong repeatability: The standardized steps (fixing-filling-smoothing-sealing-turning) constitute a complete and closed process chain, which greatly reduces the uncertainty of human operation and improves the reproducibility and reliability of the method.

[0024] In some embodiments of the present invention, in step S2, the instrument parameters for the X-ray diffraction test include: the X-ray source is a copper target; the tube voltage is 40-45kV; and the tube current is greater than or equal to 200mA.

[0025] In some preferred embodiments of the present invention, in step S2, the tube current is 200-250mA during the X-ray diffraction test.

[0026] In some embodiments of the present invention, in step S2, the instrument parameters for the X-ray diffraction test further include: a scanning range 2θ of 5°-75°; and a scanning speed of 1-1.5° / min.

[0027] In some embodiments of the present invention, in step S3, the mineral composition information includes type information and content information.

[0028] In some embodiments of the present invention, step S3, specifically, involves obtaining mineral type information by matching the X-ray diffraction pattern of the sample with an X-ray diffraction standard card, and determining the types of minerals contained in the sample based on the diffraction peak positions, relative intensities, peak shape characteristics, and geological background of the sample.

[0029] In some embodiments of the present invention, step S3, specifically, includes obtaining the mineral content information by: calculating the relative percentage content of each mineral in the sample using formula (Ⅰ) based on the determined mineral types. X i =[(I i / K i ) / ∑( I i / K i )]×100(Ⅰ); in, X i The relative percentage content of mineral i is expressed as a percentage. I i This represents the integral area of ​​the main peak of the diffraction peak selected for mineral i; K i This represents the reference strength of mineral i.

[0030] In some embodiments of the present invention, the integral area of ​​the main peak of the selected diffraction peak of mineral i I i The peaks were obtained by fitting the X-ray diffraction pattern of the sample.

[0031] In some preferred embodiments of the present invention, the peak fitting is performed using X-ray diffraction analysis software.

[0032] In some preferred embodiments of the present invention, the peak fitting is performed using XRD data analysis software with spectral processing and peak fitting functions.

[0033] In some embodiments of the present invention, the reference strength of mineral i K i Obtained by searching the X-ray diffraction standard card database.

[0034] Compared with the prior art, the beneficial effects of the present invention are: This invention applies the back-packing method to mineral composition analysis in deep-sea polymetallic sediments, effectively suppressing the preferred orientation of platy, columnar, or acicular minerals, fundamentally ensuring the authenticity of diffraction intensity information. The method for mineral composition analysis in deep-sea polymetallic sediments provided by this invention employs high-power X-ray (≥8kW) excitation and slow scanning, enhancing the diffraction signals of weakly crystalline phases and trace minerals, ensuring complete spectral information and a high signal-to-noise ratio, solving the problems of weak signals and easy omissions in conventional methods. Based on this, by integrating the matching principles of peak position, intensity, and geological background with the relative percentage content calculation formula, reliable identification and semi-quantitative calculation of complex mineral compositions are achieved. This method standardizes the analytical process, has good repeatability, and is applicable not only to oceanic polymetallic nodules but also to similar complex samples such as cobalt-rich crusts and polymetallic slimes, providing solid and reliable analytical technical support for deep-sea mineral resource research and genetic determination. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the sample holder used in the back-mounted sample preparation method in Example 1; Figure 2 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Example 1; Figure 3 This is a matching diagram of the X-ray diffraction pattern of the oceanic polymetallic nodule sample in Example 1 and the PDF standard card. Figure 4 This is a fitting diagram of the X-ray diffraction peak area of ​​the ocean polymetallic nodule sample in Example 1; Figure 5 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 1; Figure 6 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 1 is matched with the PDF standard card. Figure 7 The X-ray diffraction peak area fitting diagram of the ocean polymetallic nodule sample in Comparative Example 1 is shown. Figure 8 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 2; Figure 9 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 2 is matched with the PDF standard card. Figure 10 This is a fitting diagram of the X-ray diffraction peak area of ​​the polymetallic nodule sample from the ocean in Comparative Example 2. Figure 11 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 3; Figure 12 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 3 is matched with the PDF standard card. Figure 13 The X-ray diffraction peak area fitting diagram of the ocean polymetallic nodule sample in Comparative Example 3 is shown. Figure 14 Comparison of X-ray diffraction patterns of ocean polymetallic nodule samples in Example 1, Comparative Example 2, and Comparative Example 3. Detailed Implementation

[0036] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0037] Example 1 This embodiment provides a method for mineral composition analysis in deep-sea polymetallic sediments. The sample analyzed is a polymetallic nodule collected from the Pacific Ocean. The analysis steps are as follows: S11. The ocean polymetallic nodules are air-dried under natural conditions. The air-dried sample is crushed using an agate mortar and passed through a 200-mesh sieve (0.075mm). The powder passing through the sieve is mixed evenly to obtain ocean polymetallic nodule powder. S12. Using the back-mounted method for sample preparation, fix the aluminum hollow sample holder (hollow part size 20mm×20mm×2mm) to the frosted glass plate with a long tail clip. Use a spatula to take an appropriate amount of ocean polymetallic nodule powder and evenly and loosely sprinkle it into the groove formed by the sample holder and the frosted glass plate. Gently tap around the groove to allow the powder to settle and fill naturally. Then gently scrape it flat with a glass slide and remove excess powder to ensure that the powder in the groove is flush with the upper edge of the groove. Seal the groove opening with tape. Then rotate the sample holder and the frosted glass plate 180° as a whole, open the long tail clip, and take out the prepared sample. S21. Perform X-ray diffraction testing on the prepared sample. The instrument parameters for X-ray diffraction testing are as follows: X-ray source is a copper target, tube voltage is 40kV, tube current is 250mA (i.e., 10kW X-ray power), scanning speed is 1° / min, and scanning range is 5°-75° (2θ). Obtain the X-ray diffraction pattern of the sample. S31. Match the X-ray diffraction pattern of the sample with the PDF standard card, and determine the types of minerals in the sample based on the position, relative intensity, peak shape characteristics and geological background of the diffraction peaks. S32. Based on the determined mineral types, use MDI JADE 9.8 software for peak fitting and read the integral area of ​​the main peak of the determined mineral's diffraction peak. Obtain the reference intensity of the determined mineral by searching the PDF-4 / Minerals database, and calculate the relative percentage content of each mineral. The calculation formula is as follows: X i =[( I i / K i ) / ∑( I i / K i )]×100 in, X i The relative percentage content of mineral i is expressed as a percentage. I i This represents the integral area of ​​the main peak of the diffraction peak selected for mineral i; K i This represents the reference strength of mineral i.

[0038] Figure 1 This is a schematic diagram of the sample holder used in the back-mounted sample preparation method in Example 1.

[0039] Figure 2 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Example 1 is shown below. Figure 3 This is a matching diagram of the X-ray diffraction pattern of the oceanic polymetallic nodule sample in Example 1 and the PDF standard card. Figure 4 This is the X-ray diffraction peak area fitting diagram of the oceanic polymetallic nodule sample in Example 1, from... Figures 2-4 It can be seen that mineral composition analysis is actually a qualitative and semi-quantitative process, specifically: (1) Import the X-ray diffraction pattern of the obtained sample into MDI JADE 9.8 software, click S / M (Search / Match), the software automatically searches for matching PDF standard cards in the matching PDF-4 / Minerals database, and then carefully compares the matching degree of diffraction peak position, relative intensity, peak shape characteristics, and combined with the common mineral types in Pacific polymetallic nodules, to determine that the mineral phases contained in the sample are barium magnesium manganese ore, calcium cross zeolite, quartz, carbofluapatite and hydrous manganese ore, and complete the mineral characterization; (2) The X-ray diffraction patterns of the samples were smoothed using MDI JADE 9.8 software. After removing the background, the diffraction peaks of minerals between 5° and 45° were selected for peak area fitting. The peak positions d-values ​​of the selected peaks for barium magnesium manganese ore, calcium cross zeolite, quartz, carboapatite, and hydrous manganese ore were 1.023 nm, 0.727 nm, 0.335 nm, 0.279 nm, and 0.244 nm, respectively. After peak fitting, the integral areas of the selected diffraction peaks for barium magnesium manganese ore, calcium cross zeolite, quartz, carboapatite, and hydrous manganese ore were 92.0, 30.7, 8.9, 340.0, and 11, respectively. 70.6; The reference intensities for barium magnesium manganese ore, calcium cross zeolite, quartz, carbofluapatite, and hydrous manganese ore obtained by searching the PDF-4 / Minerals database were 1.61, 0.52, 3.41, 1.02, and 1.50, respectively. The integral area of ​​the main peak of the mineral diffraction peak obtained by peak fitting and the reference intensities obtained by the search were substituted into the relative percentage content calculation formula. The relative percentage contents of barium magnesium manganese ore, calcium cross zeolite, quartz, carbofluapatite, and hydrous manganese ore were obtained by entering the formula into Excel and calculating them to be 4.6%, 4.8%, 0.2%, 27.1%, and 63.3%, respectively.

[0040] Comparative Example 1 This comparative example provides a method for mineral composition analysis in deep-sea polymetallic sediments. The sample analyzed was a polymetallic nodule collected from the Pacific Ocean. The analytical steps are as follows: S11. The ocean polymetallic nodules are air-dried under natural conditions. The air-dried sample is crushed using an agate mortar and passed through a 200-mesh sieve (0.075mm). The powder passing through the sieve is mixed evenly to obtain ocean polymetallic nodule powder. S12. Using the positive pressure method to prepare the sample, take a portion of the ocean polymetallic nodule powder with a spatula and place it in the groove of an ordinary glass sample holder. Use another piece of frosted glass to compact the powder sample in the groove, ensuring that the compacted powder is flush with the upper edge of the groove, thus completing the sample preparation. S21. Perform X-ray diffraction test on the prepared sample. The instrument parameters for X-ray diffraction test are as follows: X-ray source is copper target, tube voltage is 40kV, tube current is 250mA, scanning speed is 1° / min, and scanning range is 5°-75° (2θ). Obtain the X-ray diffraction pattern of the sample. S31. Match the X-ray diffraction pattern of the sample with the PDF standard card, and determine the types of minerals in the sample based on the position, relative intensity, peak shape characteristics and geological background of the diffraction peaks. S32. Based on the determined mineral types, use MDI JADE 9.8 software for peak fitting and read the integral area of ​​the main peak of the determined mineral's diffraction peak. Obtain the reference intensity of the determined mineral by searching the PDF-4 / minerals database, and calculate the relative percentage content of each mineral. The calculation formula is as follows: X i =[( I i / K i ) / ∑( I i / K i )]×100 in, X i The relative percentage content of mineral i is expressed as a percentage. I i This represents the integral area of ​​the main peak of the diffraction peak selected for mineral i; K i This represents the reference strength of mineral i.

[0041] Figure 5 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 1 is shown. Figure 6 This is a comparison diagram of the X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 1 with the PDF standard card. Figure 7The X-ray diffraction peak area fitting diagram of the ocean polymetallic nodule sample in Comparative Example 1 is shown. Based on the matching degree of diffraction peak position, relative intensity, and peak shape characteristics, and combined with the common mineral types in Pacific polymetallic nodules, the mineral phases contained in the sample are determined to be hydrous manganeseite, carbofluapatite, and quartz, with relative percentage contents of 63%, 36.7%, and 0.3%, respectively.

[0042] However, in Comparative Example 1, due to the use of the positive pressure method and a common glass sample holder for sample preparation, the X-ray diffraction pattern of the sample showed a clear preferred orientation. The main peak of barium magnesium manganese ore near 1 nm was very indistinct, and after subtracting the background, the relative percentage content of this mineral could not be determined. Similarly, the main peak of calcium staurolite near 7 nm was also submerged in the background, making it impossible to calculate the relative percentage content of this mineral. Therefore, this sample preparation method led to omissions in the qualitative mineral analysis results. The error for both barium magnesium manganese ore and calcium staurolite reached 100%, making it impossible to calculate the relative percentage content of the minerals. Samples needed to be re-analyzed, resulting in decreased analytical efficiency. The quantitative results calculated based on these qualitative results were also incorrect due to the absence of these two minerals.

[0043] Comparative Example 2 This comparative example provides a method for analyzing the mineral composition of deep-sea polymetallic sediments. The sample analyzed is the same as that in Example 1. The only difference between the analytical method and Example 1 is that the tube current in the X-ray diffraction instrument parameters is changed to 100mA (i.e., 4kW X-ray power).

[0044] Figure 8 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 2 is shown. Figure 9 This is a comparison diagram of the X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 2 and the PDF standard card. Figure 10 This is the X-ray diffraction peak area fitting diagram of the oceanic polymetallic nodule sample in Comparative Example 2, based on... Figures 8-10 : (1) By matching the X-ray diffraction pattern of the sample with the PDF standard card, and by carefully comparing the matching degree of diffraction peak position, relative intensity, peak shape characteristics, and common mineral types in polymetallic nodules in the Pacific Ocean, the mineral phases contained in the sample were determined to be barium magnesium manganese ore, calcium cross zeolite, carbofluapatite and hydrous manganese ore. (2) The X-ray diffraction patterns of the samples were smoothed using MDI JADE 9.8 software. After removing the background, the diffraction peaks of minerals between 5° and 45° were selected for peak area fitting. The peak position d values ​​of the selected peak fitting main peaks of barium magnesium manganese ore, calcium cross zeolite, carbophosphate and hydrous manganese ore were 1.016 nm, 0.717 nm, 0.279 nm and 0.243 nm, respectively. After peak fitting, the integrated areas of the main peaks of the selected diffraction peaks of barium magnesium manganese ore, calcium cross zeolite, carbophosphate and hydrous manganese ore were 25.6, 8.2, 132.1 and 400, respectively. 5. The reference intensities for barium magnesium manganese ore, calcium cross zeolite, carbofluapatite, and hydrous manganese ore obtained by searching the PDF-4 / Minerals database were 1.61, 0.52, 1.02, and 1.50, respectively. The integral area of ​​the main peak of the mineral diffraction peak obtained by peak fitting and the reference intensities obtained by the search were substituted into the relative percentage content calculation formula. The relative percentage contents of barium magnesium manganese ore, calcium cross zeolite, carbofluapatite, and hydrous manganese ore were obtained by entering the formula into Excel and calculating them to be 3.7%, 3.7%, 30.2%, and 62.4%, respectively.

[0045] Comparative Example 3 This comparative example provides a method for analyzing the mineral composition of deep-sea polymetallic sediments. The sample analyzed is the same as in Example 1. The only difference between the analytical method and Example 1 is that the tube current in the X-ray diffraction instrument parameters is changed to 200mA (i.e., 8kW X-ray power).

[0046] Figure 11 The X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 3 is shown. Figure 12 This is a comparison diagram of the X-ray diffraction pattern of the oceanic polymetallic nodule sample in Comparative Example 3 with the PDF standard card. Figure 13 This is the X-ray diffraction peak area fitting diagram of the oceanic polymetallic nodule sample in Comparative Example 3, based on... Figures 11-13 : (1) By matching the X-ray diffraction pattern of the sample with the PDF standard card, and by carefully comparing the matching degree of diffraction peak position, relative intensity, peak shape characteristics, and common mineral types in polymetallic nodules in the Pacific Ocean, the mineral phases contained in the sample were determined to be barium magnesium manganese ore, calcium cross zeolite, quartz, carbofluapatite and hydrous manganese ore. (2) The X-ray diffraction patterns of the samples were smoothed using MDI JADE 9.8 software. After removing the background, the diffraction peaks of minerals between 5° and 45° were selected for peak area fitting. The peak positions d-values ​​of the selected main peaks for barium magnesium manganese ore, calcium cross zeolite, quartz, carboapatite, and hydrous manganese ore were 1.022 nm, 0.719 nm, 0.334 nm, 0.279 nm, and 0.244 nm, respectively. After peak fitting, the integrated areas of the main peaks of the selected diffraction peaks for barium magnesium manganese ore, calcium cross zeolite, quartz, carboapatite, and hydrous manganese ore were 77.7, 23.1, 10.4, 286.9, and 92, respectively. 7.6; The reference intensities for barium magnesium manganese ore, calcium cross zeolite, quartz, carbofluapatite, and hydrous manganese ore obtained by searching the PDF-4 / Minerals database were 1.61, 0.52, 3.41, 1.02, and 1.50, respectively. The integral area of ​​the main peak of the mineral diffraction peak obtained by peak fitting and the reference intensities obtained by the search were substituted into the relative percentage content calculation formula. The relative percentage contents of barium magnesium manganese ore, calcium cross zeolite, quartz, carbofluapatite, and hydrous manganese ore were obtained by entering the formula into Excel and calculating them to be 4.8%, 4.5%, 0.3%, 28.3%, and 62.1%, respectively.

[0047] Figure 14 The X-ray diffraction patterns of the oceanic polymetallic nodule samples in Example 1, Comparative Example 2, and Comparative Example 3 are compared. The only difference between the analytical methods used in Example 1, Comparative Example 2, and Comparative Example 3 is the tube current condition, which is 250mA, 100mA, and 200mA, respectively. Comparing the diffraction patterns under the three conditions, it was found that the main peak of the poorly crystallized hydrous manganeseite near 0.244nm has a similar and relatively sharp peak shape when the tube current is 200mA and 250mA, while the peak shape is relatively smooth when the tube current is 100mA, showing a large difference. Furthermore, when the tube current is 100mA, the main peak of quartz near 0.334nm cannot be identified, so the qualitative results lack one mineral. Table 1 below compares the relative deviations of the relative percentage content of minerals under three tube current conditions. The formula for calculating the relative deviation is: Relative deviation = [A - (A + B) / 2] / [(A + B) / 2] × 100, expressed as a percentage. Where A is the relative percentage content of a certain mineral under current condition A, and B is the relative percentage content of a certain mineral under current condition B. Since it is a semi-quantitative condition, the relative percentage content under conditions A and B cannot be used as the true value. Therefore, it is assumed that the average value of the relative percentage content of minerals under the two conditions is the true value.

[0048] Table 1. Comparison of relative deviations in mineral percentage content under three tube current conditions

[0049] As shown in Table 1, in Comparative Example 2, when the tube current was 100mA, quartz could not be identified, resulting in a 100% relative deviation in the relative percentage content of quartz compared to Example 1 and Comparative Example 3. Furthermore, the relative deviations in the relative percentage contents of barium magnesium manganese ore, calcium cross zeolite, and carbofluapatite were also generally high. In contrast, when the tube current was 200mA and 250mA, the relative deviations in the relative percentage contents of each mineral were relatively smaller. Although the relative deviation of quartz reached 20%, this was mainly due to the lower relative percentage content of quartz. Therefore, the analytical method provided by this invention is more effective when the tube current is 200mA or 250mA.

Claims

1. Application of back-mounted sample preparation in mineral composition analysis of deep-sea polymetallic sediments.

2. The application according to claim 1, characterized in that, The deep-sea polymetallic sediments are selected from one of the following: oceanic polymetallic nodules, deep-sea cobalt-rich crusts, and deep-sea polymetallic mud.

3. A method for mineral composition analysis in deep-sea polymetallic sediments, characterized in that, Includes the following steps: S1. Collect deep-sea polymetallic sediments to be tested and prepare samples using the back-loading method; S2. Perform X-ray diffraction tests on the prepared sample to obtain the X-ray diffraction pattern of the sample. S3. By analyzing the X-ray diffraction pattern obtained in step S2, information on the mineral composition of deep-sea polymetallic sediments is obtained.

4. The component analysis method according to claim 3, characterized in that, In step S1, the particle size of the deep-sea polymetallic sediment to be tested is less than 200 mesh.

5. The component analysis method according to claim 3, characterized in that, In step S2, the instrument parameters for the X-ray diffraction test include: the X-ray source is a copper target; the tube voltage is 40-45kV; and the tube current is greater than or equal to 200mA.

6. The component analysis method according to claim 5, characterized in that, In step S2, the instrument parameters for the X-ray diffraction test also include: a scanning range of 2θ of 5°-75°; and a scanning speed of 1-1.5° / min.

7. The component analysis method according to claim 3, characterized in that, In step S3, the mineral composition information includes type information and content information.

8. The component analysis method according to claim 7, characterized in that, In step S3, obtaining mineral type information specifically includes: matching the X-ray diffraction pattern of the sample with an X-ray diffraction standard card, and determining the types of minerals contained in the sample based on the diffraction peak position, relative intensity, peak shape characteristics, and geological background of the sample.

9. The component analysis method according to claim 8, characterized in that, In step S3, obtaining the mineral content information specifically includes: calculating the relative percentage content of each mineral in the sample using formula (Ⅰ) based on the determined mineral types: X i =[( I i / K i ) / ∑( I i / K i )]×100(Ⅰ)； in, X i The relative percentage content of mineral i is expressed as a percentage. I i This represents the integral area of ​​the main peak of the diffraction peak selected for mineral i; K i This represents the reference strength of mineral i.

10. The component analysis method according to claim 9, characterized in that, The integral area of ​​the main peak of the diffraction peak selected by mineral i I i The peaks of the X-ray diffraction pattern of the sample were obtained by peak fitting. And / or, the reference strength of mineral i K i Obtained by searching the X-ray diffraction standard card database.

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