Method for determining content of apatite in deep-sea sediment
By combining X-ray diffraction and infrared spectroscopy analysis, the ratio of apatite to quartz in deep-sea sediments can be identified and calculated, solving the problem of the difficulty in accurately determining the apatite content in existing technologies. This achieves highly accurate apatite content determination and has wide applicability.
Patent Information
- Application Number
- CN202510980597.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-16
- Publication Date
- 2025-10-17
AI Technical Summary
Existing technologies make it difficult to accurately identify and measure the relative content of apatite in deep-sea sediments, especially because X-ray diffraction analysis methods cannot effectively identify the spectral signals of apatite and are interfered with by other mineral signals.
The method of combining X-ray diffraction and infrared spectroscopy was used to identify the relative content of minerals in sediments, calculate the ratio of characteristic peak areas of apatite to quartz, and combine the relative content of quartz obtained from X-ray diffraction spectra with normalization to determine the relative content of apatite.
The method enables accurate determination of apatite content in deep-sea sediments, and shows a significant positive correlation with P2O5 and CaO content in the sediments. The method is adaptable to samples from different sea areas, improving the accuracy of the measurement.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of component analysis, and particularly relates to a method for determining the content of apatite in deep-sea sediments. BACKGROUND
[0002] Rare earth resources are key mineral resources widely used in emerging industries such as new materials, new energy and information technology, and their importance is self-evident.
[0003] Deep-sea rare earth, also known as deep-sea rare earth-rich sediment, is a new type of rare earth resource discovered in recent years, mainly distributed in deep-sea basins of 4000-6000m, rich in medium-heavy rare earth, and the resource potential far exceeds that of land. The discovery of deep-sea rare earth will have a profound impact on the pattern of world rare earth resources. Although deep-sea rare earth-rich sediment, as a new type of seabed resource, was discovered and paid attention to relatively late (first reported in 2011), given that deep-sea rare earth and polymetallic nodule have similar production environments and often coexist, the main mining technology of polymetallic nodule is also applicable to deep-sea rare earth. Generally speaking, deep-sea rare earth may become one of the first batch of developed deep-sea mineral resources together with polymetallic nodule.
[0004] The discovery of deep-sea rare earth-rich sediment has attracted widespread attention at home and abroad, and a large number of studies have been carried out on its rare earth enrichment mechanism and controlling factors. The occurrence of rare earth elements in rare earth-rich sediment is a key problem in the study of rare earth-rich sediment mineralization, and is also the basis for the development and utilization of rare earth resources in deep-sea sediments. The latest research shows that biogenic apatite is the main occurrence of rare earth elements in rare earth-rich sediment, and is also the final host mineral. However, due to the low crystallinity of apatite in the sediment, the X-ray diffraction analysis method cannot effectively identify the spectrum signal of apatite, and the spectrum signal of apatite is also disturbed by other mineral signals, so it is difficult to directly determine the relative content of apatite.
[0005] Therefore, it is of great significance to establish a method for accurately calculating the relative content of apatite in deep-sea sediments for analyzing the occurrence characteristics and content of rare earth elements in deep-sea sediments, identifying the mineralization characteristics and formation mechanism of deep-sea sediments, and selecting and smelting and utilizing deep-sea sediments. SUMMARY
[0006] The present application provides a method for determining the content of apatite in deep-sea sediments, comprising the following steps: (1) X-ray analysis of the relative content of minerals The relative content of minerals in the sediment is obtained by identifying and analyzing the sediment by X-ray diffraction spectrum; (2) Determining the content ratio of apatite and quartz minerals The infrared spectrum of the sediment is measured, and on the basis of identifying the quartz and apatite spectrum peaks, the spectrum peak area of the characteristic peaks of quartz and apatite is integrated to determine the peak area ratio of apatite and quartz, so as to obtain the content ratio of apatite and quartz minerals; (3) Normalization processing of mineral content The content ratio of apatite and quartz obtained by the infrared spectrum is combined with the relative content of quartz obtained by the X-ray diffraction spectrum to obtain the relative content of apatite; then the obtained relative contents of each mineral are normalized to calculate the relative contents of each mineral in the normalized sediment, so as to finally accurately obtain the relative content of apatite in the sediment.
[0007] In the above calculation method, in the step (1), the calculation formula of the relative content of minerals in the sediment is as follows: ; In the formula, x i is the percentage content of mineral i in n quantifiable minerals; K i is the intensity factor of mineral i; and I i is the integral intensity of mineral i.
[0008] In the above method, in the step (1), the mineral is one or more of quartz, feldspar, illite, montmorillonite, calcium cross-boiling, halite, kaolinite and clinoptilolite, etc.; the selection of minerals can be adjusted according to the actual situation of minerals contained in the sediment, and the X-ray identification and analysis are used as the criterion.
[0009] In the above method, in the step (2), in the infrared spectrum, the characteristic peak of quartz is selected as 798 cm -1 , and the characteristic peak of apatite is selected as 565 cm -1 .
[0010] In the above method, in the step (3), in the normalization processing, the calculation formula of the relative content of each mineral is as follows: the relative content of each mineral = the content of each mineral / the total content of all minerals.
[0011] In the above calculation formula, the content of each mineral is the relative content of each mineral measured by X-ray or the relative content of apatite obtained by calculation; and the total content of all minerals is the sum of the relative content of all minerals measured by X-ray and the relative content of apatite obtained by calculation.
[0012] In one specific embodiment, in the formula, each mineral content is the relative content of quartz, feldspar, illite, montmorillonite, calcium cross-boiling, halite, kaolinite or clinoptilolite determined by X-ray measurement, or the relative content of apatite obtained by calculation; the total content of all minerals is the sum of the relative content of quartz, feldspar, illite, montmorillonite, calcium cross-boiling, halite, kaolinite and clinoptilolite determined by X-ray measurement and the relative content of apatite obtained by calculation.
[0013] In order to calibrate the accuracy of the above method in determining the content of apatite, the content of major elements in the sediment can be measured, and the correlation between the major elements and the content of apatite is analyzed.
[0014] In the above calibration procedure, ICP-OES is used to measure the content of major elements in the sediment; the major elements are P2O5 and CaO.
[0015] In the present application, the purpose of determining the content of major elements P2O5 and CaO is to verify the accuracy of the method described in the present application in determining the content of apatite in the sediment. If it is determined that the obtained content of apatite is positively correlated with the content of major elements P2O5 and CaO, it indicates that the determination method of the present application is more accurate.
[0016] The present application provides the application of the above method in the analysis of the occurrence of rare earth elements in deep-sea sediments and the beneficiation and utilization of deep-sea sediments.
[0017] The beneficial effects of the present application are: The present application establishes a method for determining the relative content of apatite in deep-sea sediments. The content of apatite obtained by the method is positively correlated with the content of P2O5 and CaO in the sediment, which indicates that the method for determining the relative content of apatite described in the present application has high accuracy, and the method is adaptable to sediment samples in different sea areas. The determination method of the present application has important significance for analyzing the occurrence of rare earth elements in deep-sea sediments, identifying the ore-forming characteristics and formation mechanism of deep-sea sediments, and the beneficiation and utilization of deep-sea sediments. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 The characteristic peak area of quartz (left: 798 cm -1 ) and apatite (right: 565 cm -1 ) in the infrared spectrum of the sediment sample 67-PGC23 (600-602 cm) of the Pacific Ocean; Figure 2 The relationship between the content of apatite in the sediment and the content of P2O5 and CaO. DETAILED DESCRIPTION
[0019] Other materials employed in the present application, unless otherwise stated, are available from commercial sources. Other terms used in the present application, unless otherwise defined, have the meanings ordinarily understood by one of ordinary skill in the art. The present application is further described in the following detailed description with reference to the accompanying drawings, and data. The following examples are merely illustrative of the present application and do not in any way limit the scope of the present application.
[0020] Example 1 The test analysis was carried out on sediments collected from deep-sea basins in the Indian Ocean and the Pacific Ocean (generally with a water depth of more than 4000 m), and the steps were as follows: 1. Sample processing The wet sample of the sediment was pre-frozen and then placed in a freeze dryer or an oven for drying at 60°C, and was ground to about 200 mesh (74 μm) with a maroon mortar and then mixed.
[0021] 2. Analysis process The ground deep-sea sediment was subjected to infrared spectrum analysis and X-ray diffraction analysis by using a Fourier infrared spectrometer and an X-ray diffraction analyzer, respectively, to obtain the infrared spectrum spectrum and the X-ray diffraction spectrum of the deep-sea sediment.
[0022] The test procedure of the X-ray diffraction analysis refers to the operation requirements in the sediment whole rock mineral identification in the Oceanographic Survey Specification Part 12: Marine Geological Survey (GB / T 12763.12). Specifically, the scanning range of the X-ray diffraction analyzer is 3°~65° (2θ), the step is 0.02°, and the scanning speed is 2° / min; and the goniometer angle accuracy is better than 0.05° (2θ).
[0023] 3. Analysis result processing (1) Relative content of minerals in X-ray analysis The relative content (W -1 ) of quartz, feldspar, illite, montmorillonite, calcic zeolite, halite, kaolinite and clinoptilolite, etc. in the deep-sea sediment was identified and analyzed by using the X-ray diffraction spectrum of the deep-sea sediment.
[0024] The spectrum identification and analysis procedure refers to the operation requirements in the quantitative analysis of the sediment whole rock mineral identification in the Oceanographic Survey Specification Part 12: Marine Geological Survey (GB / T 12763.12). The specific operation includes: smoothing the diffraction data graph, deducting the background, completing the diffraction peak separation and retrieval by using computer software. The diffraction data are compared with the JCPDS (Joint Committee on Powder Diffraction Standards) card to finally determine the phase composition. The method used by Cook et al. (1975) in the Deep Sea Drilling Project (DSDP) is generally used to calculate the relative content of minerals in the whole rock mineral quantitative analysis. When calculating the relative content of minerals, the following formula is used: wherein: x i is the percentage content of mineral i in n quantifiable minerals; K i is the intensity factor of mineral i; I i is the integral intensity of mineral i.
[0025] The calculation results are shown in Table 1: Table 1. Data table of main trace element content and mineral relative content of sediments (2) Calculation of apatite and quartz mineral content ratio by infrared spectrum The content ratio of apatite and quartz in sediments is obtained by infrared spectrum of deep-sea sediments. The specific operation includes: baseline correction, peak identification and integration of the diffraction data spectrum by computer software processing. On the basis of identifying the characteristic peaks of quartz and apatite (the apatite content of some deep-sea sediment samples is too low to identify the characteristic peak), the characteristic peak area of quartz and apatite is integrated, as shown in Figure 1 , wherein the characteristic peak of quartz is generally selected as 798 cm -1 , and the characteristic peak of apatite is generally selected as 565 cm -1 . The peak area ratio of apatite and quartz (A 磷灰石 / A 石英 ) is calculated to obtain the content ratio of apatite and quartz minerals.
[0026] The calculation results are shown in Table 2.
[0027] (3) Normalization processing of mineral content The relative content of apatite (W 磷灰石-2 ) is calculated by combining the content ratio of apatite and quartz obtained by infrared spectrum with the relative content of quartz obtained by X-ray diffraction spectrum. The obtained relative contents of each mineral are re-normalized to comprehensively calculate the relative contents (W -3 ) of apatite, quartz, feldspar, illite, montmorillonite, calcium cross-boiling, halite, kaolinite and clinoptilolite in deep-sea sediments.
[0028] The calculation formula of the relative content of each mineral after normalization processing: The relative content of each mineral = the content of each mineral / the total content of all minerals; In the above formula, the content of each mineral is the relative content of quartz, feldspar, illite, montmorillonite, phillipsite, rock salt, kaolinite or clinoptilolite determined by X-ray, or the relative content of apatite obtained by calculation; the total content of all minerals is the sum of the relative contents of quartz, feldspar, illite, montmorillonite, phillipsite, rock salt, kaolinite and clinoptilolite determined by X-ray and the relative content of apatite obtained by calculation.
[0029] The normalization results are shown in Table 2: Table 2 Apatite to quartz content ratio calculated by infrared spectroscopy and relative mineral content after normalization in sediments (4) Calibration In order to calibrate the accuracy of the method described in the present invention in determining the apatite content, ICP-OES and ICP-MS can be used to measure the contents of major elements (P2O5 and CaO) and rare earth elements (REEs) in the sediments, respectively, and the correlation between the major elements (P2O5 and CaO) and the apatite content can be analyzed.
[0030] The test results are as follows Figure 2 As shown: According to the above test results, after normalization and calculation, the apatite content in the sediments showed a clear positive correlation with the P2O5 and CaO contents. This demonstrates that the method for calculating the relative apatite content described in this invention has high accuracy and is adaptable to sediment samples from different marine areas. Apatite is a calcium phosphate with the chemical formula Ca5(PO4)3(F,Cl,OH). The P2O5 and CaO contents in sediments are primarily derived from apatite. Therefore, the clear positive correlation between the calculated apatite content and the measured P2O5 and CaO contents demonstrates the accuracy of the method described in this invention.
[0031] In practice, X-ray diffraction analysis cannot effectively identify apatite's spectral signal due to its low degree of crystallization in sediments. Furthermore, the apatite spectral signal is also affected by interference from other minerals, making it difficult to directly determine the relative content of apatite using X-ray analysis. In other words, X-ray diffraction analysis can effectively identify minerals such as quartz in deep-sea sediments, but it cannot directly identify apatite.
[0032] While infrared spectroscopy is advantageous in identifying the relative contents of quartz and apatite, identifying other minerals is more difficult. Therefore, infrared spectroscopy can be used to determine the ratio of quartz to apatite. Combined with the relative contents of quartz and other minerals obtained by X-ray analysis, the relative content of apatite can be calculated.
[0033] The X-ray identifiable mineral phase relative content in the obtained deposit is added to 100% by X-ray diffraction analysis. The ratio of apatite to quartz can be obtained by infrared spectrum, and the relative content of apatite can be calculated by using the ratio and combining the relative content of quartz obtained by X-ray analysis. At this time, the sum of the relative content of the minerals identified by X-ray and the relative content of apatite calculated will exceed 100%. By normalization processing, the relative content of each mineral added to 100% can be obtained.
[0034] In addition, in the deposit, quartz is a common and stable mineral phase, and the signal peak in the X-ray diffraction and infrared spectrum of quartz is clear and easy to identify, so quartz is the best intermediate mineral as the two spectrum analysis methods.
[0035] In summary, the present application obtains the X-ray identifiable mineral phase relative content (i.e. quartz, feldspar, illite, montmorillonite, calcium cross-boiling, rock salt, kaolinite and clinoptilolite, not including apatite) in the deposit by X-ray diffraction analysis, and the above mineral phase relative content is added to 100%. Then the ratio of apatite to quartz in the deposit is obtained by infrared spectrum. The relative content of apatite can be calculated by using the ratio of apatite to quartz and combining the relative content of quartz obtained by X-ray analysis. At this time, the sum of the relative content of the minerals identified by X-ray and the relative content of apatite calculated will exceed 100%, and then the relative content of each mineral (including apatite) can be recalculated by each mineral relative content / (X-ray identifiable mineral relative content + calculated relative content of apatite), which is the normalization processing. At this time, the relative content of each mineral is added to 100%, so that the content of apatite in the deposit is determined.
[0036] The above is only a preferred embodiment of the present application, and does not limit other forms of the present application. Any skilled person in the art can modify or change the above disclosed technical content to equivalent embodiments. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application, which does not deviate from the technical solution content of the present application, still belongs to the protection scope of the present application.
Claims
1. A method for determining the apatite content of deep-sea sediments, characterized in that: The steps include: (1) X-ray analysis of relative content of minerals Use X-ray diffraction spectra to identify and analyze sediments and obtain the relative content of minerals in the sediments; (2) Determine the ratio of apatite and quartz mineral content Determine the infrared spectrum of the sediment, identify the quartz and apatite peaks, integrate the peak areas of the characteristic peaks of quartz and apatite, determine the peak area ratio of apatite to quartz, and obtain the apatite to quartz mineral content ratio; (3) Normalization of mineral content The relative content of apatite is obtained by combining the apatite to quartz content ratio obtained from infrared spectroscopy with the relative quartz content obtained from X-ray diffraction spectroscopy. The relative contents of each mineral obtained are then normalized to calculate the relative content of each mineral in the sediment after normalization, thereby ultimately accurately obtaining the relative content of apatite in the sediment.
2. The method for determining the apatite content in deep-sea sediments according to claim 1, wherein: In step (1), the calculation formula for the relative content of minerals in the sediment is as follows: ； Where: x i is the percentage of mineral i in n quantifiable minerals; K i is the intensity factor of mineral i; I i is the integrated intensity of mineral i.
3. The method for determining the apatite content in deep-sea sediments according to claim 1, wherein: In the step (1), the mineral is one or more of quartz, feldspar, illite, montmorillonite, phillipsite, rock salt, kaolinite, and clinoptilolite.
4. The method for determining the apatite content in deep-sea sediments according to claim 1, wherein: In the step (2), the characteristic peak of quartz in the infrared spectrum is selected at 798 cm -1 The characteristic peak of apatite is 565 cm -1 .
5. The method for determining the apatite content in deep-sea sediments according to claim 1, characterized in that: In the step (3), in the normalization process, the relative content of each mineral is calculated as follows: relative content of each mineral = content of each mineral / total content of all minerals.
6. The method for determining the apatite content in deep-sea sediments according to claim 5, characterized in that: The content of each mineral is the relative content of each mineral determined by X-ray or the relative content of apatite obtained by calculation; the total content of all minerals is the sum of the relative content of all minerals determined by X-ray and the relative content of apatite obtained by calculation.
7. The method for determining the apatite content in deep-sea sediments according to claim 1, characterized in that: The method further comprises a calibration step.
8. The method for determining the apatite content in deep-sea sediments according to claim 7, characterized in that: The calibration step is: using ICP-OES to measure the content of major elements in the sediment, and analyzing the correlation between the major elements and the apatite content. If the apatite content is positively correlated with the major element content, it indicates that the method has good accuracy.
9. The method for determining the apatite content in deep-sea sediments according to claim 8, characterized in that: The main elements are P2O5 and CaO.
10. Application of the method according to claim 1 in the analysis of the characteristics and content of rare earth element minerals in deep-sea sediments and in the beneficiation and smelting of deep-sea sediments.