Ore crystal form change monitoring method based on Raman spectrum technology

Abstract

The invention discloses an ore crystal form change monitoring method based on a Raman spectrum technology. The ore crystal form change monitoring method can be widely applied to crystal form change monitoring of ore in related processing processes. The method mainly comprises the steps of sample preparation, heating condition setting, Raman spectrum data acquisition after treatment at different temperatures, data recording, preliminary analysis and the like. The method has the advantages of simplicity and convenience in operation, high accuracy, nondestructive testing and the like, a basis can be provided for optimization of ore processing technological parameters, the extraction purity and efficiency of target elements can be improved, and the production cost can be reduced. Accurate mastering of the crystal transformation temperature of the ore is beneficial for accelerating development of a mineral extraction process, increasing the extraction rate of substances, reducing exploration cost and providing guarantee for research, development and production of ore-related products, and has great significance in traditional metal smelting, emerging material preparation and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of ore extraction and relates to a method for monitoring ore crystal form changes based on Raman spectroscopy technology. Background Art

[0002] In the field of mineral research, ore crystal transformation is an extremely critical phenomenon. Many minerals will undergo crystal transformation under specific physical and chemical conditions, such as changes in temperature, pressure, and chemical shock. This transformation involves the reconstruction of the atomic arrangement inside the crystal, which leads to significant changes in the physical and chemical properties of the crystal. Crystal transformation has a profound impact on the industrial application of minerals. Ores with different crystal forms may have huge differences in hardness, solubility, conductivity, etc. Take quartz ore as an example. The main component of quartz is SiO 2 . When producing materials such as glass and ceramics, the crystal form change of quartz ore has a great influence on the product performance. In the glass manufacturing process, the crystal form transformation of quartz ore at high temperature will affect the transparency, hardness and thermal stability of the glass. Appropriate crystal form transformation can make the produced glass have better optical and physical properties, meeting the needs of different application scenarios, such as architectural glass, optical instrument lenses, etc. 3 O 4 ), in the process of steel smelting, crystal transformation is very important. Under certain temperature and reduction conditions, the crystal form of magnetite will change, and gradually transform into a form that is more conducive to the extraction of iron. By controlling the crystal transformation, the recovery rate of iron can be improved, and the content of impurities can be reduced, thereby improving the quality of steel. Taking lithium ore as an example, among lithium ore resources, spodumene is the most important and has large reserves. It is the main source of commercial lithium extraction from ore. Its high-temperature transformation from α-type to β-type is conducive to lithium extraction, and crystal transformation roasting is the key to traditional lithium extraction technology. α-spodumene is dense and has low activity. After high temperature transformation to tetragonal β-spodumene, the chemical activity increases. Petroleum feldspar also thermally decomposes into β-spodumene and SiO at 1100°C. 2 Therefore, the lithium extraction process of β-spodumene is also applicable to petalite. The quality of spodumene crystal transformation is closely related to the amount of lithium extraction. The ideal transformation of crystal form can increase the amount of lithium extraction, while the poor transformation will reduce the efficiency of lithium extraction, reduce the amount of lithium extraction, and may also affect the stability and reliability of the process, increase the cost and difficulty. In short, the crystal transformation of ore is an important factor affecting the efficient utilization of ore resources and the development of related industries. In-depth research on it will help optimize the production process, improve product quality and industrial benefits.

[0003] At present, XRD technology has unique advantages in the process of ore crystal transformation. It can accurately identify the phase by X-ray diffraction of the ore and analyzing the diffraction spectrum to provide qualitative and quantitative information. At the same time, it can also study the process, degree and related crystal structure changes of crystal transformation, determine the appropriate roasting parameters, and provide important basis for checking the roasting effect, optimizing the roasting and lithium extraction process, and controlling the quality of ore salt. However, for amorphous or partially amorphous ore samples, XRD may not provide accurate structural information. In addition, the XRD technology has relatively low detection sensitivity for trace impurities or defects in ore samples, and it may be difficult to detect some trace components or structural defects that have an important impact on crystal transformation and material extraction process. At the same time, XRD testing requires sample crushing, which takes a long time to test.

[0004] Raman spectroscopy can obtain information on molecular vibration and crystal structure, distinguish crystal forms based on the changes in chemical bond vibrations of different crystal forms of ores, and is sensitive to small changes in crystal structure, making it suitable for studying crystal transformations. Its non-destructive, multi-component detection and high sensitivity can be used in ore processing. It can accurately and non-destructively detect changes in crystal forms at high temperatures, and real-time monitoring can help adjust process parameters, improve extraction efficiency and purity, and reduce costs. Raman analysis can ensure the stability of ore raw material quality and provide strong support for product research and development and production. It is of great significance in both traditional and emerging ore processing fields. The non-destructive detection characteristics are also in line with the concept of sustainable development, reducing resource loss and environmental pollution, and promoting the healthy development of the industry. Summary of the invention

[0005] The present invention aims to provide a method for detecting the crystal transformation of ores under high temperature heating based on Raman spectroscopy technology. The method has the advantages of simple operation, high accuracy, and non-destructive detection, and can be widely used in ore extraction process optimization, mineralogy research, and the development of new energy fields.

[0006] To achieve the above purpose, the present invention discloses the following technical contents A method for monitoring ore crystal changes based on Raman spectroscopy technology is characterized by the following steps: (1) Sample preparation: Grind the ore in a mortar, sieve out 1-2 mm particles through a sieve, and divide the samples into equal parts; (2) Heating conditions: Place the ore sample in a high-temperature heating container and place it in a muffle furnace to increase the temperature. After the muffle furnace cools down to room temperature, take out the sample; (3) Raman spectroscopy data acquisition: Open the Raman spectroscopy analysis software and laser control software, and use the Raman probe to collect spectra; the Raman spectroscopy data acquisition refers to the process of emitting laser light through a laser, which is transmitted to the probe via an optical fiber. The probe irradiates the laser light onto the ore sample, and the generated Raman scattered light is collected by the probe and then transmitted to the CCD detector via the incident light optical fiber. The CCD detector converts the optical signal into an electrical signal and transmits it to the data processing system for analysis and processing. The Raman spectrometer is used to irradiate the sample with laser light, collect, measure and record the generated Raman scattered light to obtain data that can reflect the molecular structure characteristics of the sample; (4) Data recording and preliminary analysis: Record the Raman spectra of ores with different temperature gradients, conduct preliminary analysis on the collected Raman spectrum data, and observe the changes in Raman peak position and intensity.

[0007] The ore described in the present invention refers to lithium ore, quartz, titanium dioxide, calcium carbonate, zirconium oxide, spodumene, aluminum oxide, mica, and magnetite. The lithium ore refers to spodumene and petalite.

[0008] The present invention provides that the change of Raman peak position and intensity is observed when the ore conversion temperature is 500-2500°C, the conversion time is 15min-60min, and the Raman peak intensity is observed and measured. The ore is placed in a muffle furnace and heated to a temperature of 500-2500°C. After the heating is completed, the ore is cooled to room temperature and taken out. The optimal crystal transformation temperature and time of spodumene β-spodumene are 1050°C and 30min.

[0009] It is particularly emphasized that when using the wavelength of the Raman analyzer and the Raman probe, different wavelengths should be selected according to the background fluorescence of the ore. The stronger the fluorescence, the darker the color, and the longer the excitation wavelength. The basis for the crystal transformation is that the characteristic peak of the Raman spectrum of the previous crystal disappears, and a new Raman characteristic peak appears, and with the change of temperature, a certain regularity changes.

[0010] The present invention further discloses the application of a method for monitoring ore crystal form changes based on Raman spectroscopy technology in accurately monitoring the ore crystal form transformation process; the accurate monitoring refers to the rapid detection and process monitoring of ore crystal form transformation. Experimental results show that the method can dynamically and accurately observe the changes in Raman peaks before and after the ore crystal form transformation.

[0011] The present invention is described in more detail as follows Ø (1) Sample preparation: First, grind the ore concentrate with a mortar, sieve out 1-2 mm particles, and divide the samples into equal parts, 5 g each; Ø (2) Heating condition setting: Place the ore sample in a high-temperature heating container Ark and place it in a muffle furnace. Set the heating rate to 7°C / min and heat at a constant temperature for 30 minutes. After the muffle furnace cools down to room temperature, take out the sample; Ø (3) Raman spectroscopy data acquisition: Open the Raman spectroscopy analysis software and laser control software, and use the Raman probe to collect spectra; set the power to 200mw, 10s integration time, and 5 averages; the Raman spectroscopy data acquisition refers to the process of using a Raman spectrometer to apply laser irradiation to the sample, collect, measure and record the Raman scattered light generated by it to obtain data that can reflect the molecular structure characteristics of the sample; Ø (4) Data recording and preliminary analysis: record the Raman spectra of ores with different temperature gradients, conduct preliminary analysis on the collected Raman spectrum data, and observe the changes in Raman peak position and intensity; Determine the optimal crystal conversion time and temperature and verify: at a temperature of 500-2500°C, when the crystal has been converted, the optimal crystal conversion temperature is determined by observing the intensity of the Raman peak of the ore after the conversion; at the determined optimal conversion temperature, set different time gradients of 15min, 30min, 45min, and 60min to observe the measured Raman peak intensity to determine the optimal conversion temperature and heating time. The present invention further discloses the application of a method for monitoring ore crystal changes based on Raman spectroscopy technology in the precise monitoring of the ore crystal transformation process, and the precise monitoring refers to the rapid detection and process monitoring of the ore crystal transformation, that is, determining the optimal crystal transformation temperature and time. Taking spodumene as an example, finding the node of the optimal crystal transformation can make spodumene change from α to β to the greatest extent, which is convenient for subsequent lithium extraction, because the α type is not easy to participate in the subsequent lithium extraction process. The lithium ore crystal forms mainly refer to: spodumene and petalite. The experimental results show that the method of the present invention can accurately grasp the crystal transformation status of the ore, which is beneficial to ensure the stable quality of the ore raw materials and provide a solid guarantee for the research and development and production of products based on various ore raw materials. Taking some special products as an example, their working principles are often closely related to the characteristics and reaction processes of specific elements or substances in the ore. In these processes, the purity of the ore raw materials plays a decisive role. By optimizing the processing technology with the method of the present invention and ensuring the stable quality of the ore raw materials, its purity can be effectively improved to meet the strict requirements of related products for the purity of ore raw materials. It is of great significance both in the field of traditional metal smelting products and in emerging special material products.

[0012] Compared with the prior art, the method for monitoring ore crystal form changes based on Raman spectroscopy technology disclosed in the present invention has the following positive effects: (1) The method of the present invention is easy to operate and can monitor the crystal transformation process of the ore.

[0013] (2) Non-destructive testing technology is used, which causes minimal damage to the sample; amorphous substances can be detected.

[0014] (3) Fast and convenient, with quick detection and easy operation, it is conducive to rapid on-site analysis and real-time monitoring.

[0015] (4) The present invention can be applied to the monitoring of crystal form change during high-temperature heating of ores, the fields of mineralogy and geology, and provide technical support for improving the development and utilization of ore resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is the XRD diagram of spodumene with different temperature gradients in the present invention; Figure 2 The Raman spectra of spodumene with different temperature gradients in the present invention; Figure 3 The Raman spectra of spodumene at different time gradients in the present invention; Figure 4 The figure is a comparison diagram of the Raman spectrum intensity of β-spodumene at different temperature gradients and time gradients in the present invention. DETAILED DESCRIPTION

[0017] The present invention is described below by specific embodiments. Unless otherwise specified, the technical means used in the present invention are methods known to those skilled in the art. In addition, the embodiments should be understood as illustrative rather than limiting the scope of the present invention, and the essence and scope of the present invention are limited only by the claims. For those skilled in the art, various changes or modifications to the material composition and dosage in these embodiments, without departing from the essence and scope of the present invention, also belong to the protection scope of the present invention. The raw materials and reagents used in the present invention are all commercially available. Example

[0018] Ø (1) Sample preparation: First, grind the spodumene concentrate with a mortar, filter out particles of about 1 mm through a sieve, and divide the samples into equal parts, 5 g each.

[0019] (2) Setting the heating conditions: Place the spodumene sample in a high-temperature heating container (Ark) and place it in a muffle furnace. Set the heating rate to 7°C / min and heat at a constant temperature for 30 minutes until it reaches 1000°C. After the muffle furnace is cooled to room temperature, take out the sample.

[0020] (3) Raman spectroscopy data acquisition: Open the Raman spectroscopy analysis software and laser control software, and use the Raman probe to collect spectra. Set the power to 200mw, 10s integration time, and 5 averages.

[0021] (4) Data recording and preliminary analysis: Record the Raman spectra of spodumene at different temperature gradients, conduct preliminary analysis on the collected Raman spectrum data, and observe the changes in Raman peak position and intensity.

[0022] (5) Determine the optimal crystal conversion time and temperature and verify: At a temperature of 1000°C, when it has been transformed into β-spodumene, the optimal crystal conversion temperature is determined by observing the intensity of the Raman peak of the transformed spodumene. At the determined optimal conversion temperature, set different time gradients of 15min, 30min, 45min, and 60min to observe the measured Raman peak intensity to determine the optimal conversion temperature and heating time. XRD and Raman spectrum comparison Figure 1-Figure 2 The results show that 1. XRD diffraction peaks overlap, while Raman spectra have relatively clear peaks. 2. XRD: mainly provides information related to crystal structure, such as lattice constant, interplanar spacing, phase composition, etc., mostly at the macroscopic crystal level. Raman spectroscopy: can reflect molecular vibration and lattice vibration information, understand chemical bonds, crystal microstructure changes, etc., and provide more details from a microscopic perspective.

[0023] Conclusion: Raman spectroscopy has obvious advantages over XRD in ore crystal form detection: sample processing is simpler and the quantity requirement is low; the detection ability is stronger and can distinguish similar structures; data analysis is easy; the instrument is portable and safe; and more comprehensive detection information can be obtained. In general, Raman spectroscopy can complete the task of ore crystal form detection more efficiently, accurately, conveniently and safely, providing strong support for related research and applications.

[0024] Advantages of Raman online analysis: It can monitor the crystal form and other characteristics of the ore in real time and provide quick feedback, which is convenient for timely adjustment of process parameters such as ore dressing. Portable instruments can be tested in situ on site to reduce the risk of sample transportation. It can adapt to a variety of working conditions and various types of ore samples, and can operate stably in harsh environments. The data analysis is accurate and can provide reliable support for on-site decision-making. It can obtain comprehensive information to help optimize the process of ore mining, processing, etc. Example

[0025] A method for monitoring crystal form changes of lithium ore based on Raman spectroscopy technology, this implementation case is a Raman spectroscopy process analysis of crystal form changes of spodumene ore under high temperature heating, and the Raman process analysis method is used to replace the traditional XRD to find the high temperature heating temperature and time for the best crystal form transformation, including the following method steps: S1: Taking spodumene concentrate as an example, it is placed in a crusher for pulverization, and then further ground using a mortar, and then screened through a sieve to select particles with a diameter of 1-2mm.

[0026] S2: Place the screened spodumene sample into a high-temperature heating ark, and then place it in a muffle furnace for high-temperature heating to 850°C, 900°C, 950°C, 1000°C, 1025°C, 1050°C, 1075°C, and 1100°C. After heating is completed, cool to room temperature and take it out.

[0027] S3: In the Raman spectrum acquisition software module, set the laser output power to 200mw, the average number to 5, and the integration time to 10s. The laser is emitted by the laser, which is transmitted to the probe via the optical fiber. The probe irradiates the laser onto the spodumene sample. The generated Raman scattered light is collected by the probe and transmitted to the CCD detector via the incident light optical fiber. The CCD detector converts the optical signal into an electrical signal and transmits it to the data processing system for analysis and processing.

[0028] S4: Preprocess the spodumene Raman spectrum collected in S3, including removing cosmic ray interference and background fluorescence baseline (method reference "Application of Raman spectroscopy analysis technology in resource microbial fermentation performance evaluation [J]. Journal of Microbiology, 2022, 62(11): 4262-4272. DOI: 10.13343 / j.cnki.wsxb.20220762.") to eliminate the influence of noise. Collect the Raman spectra of spodumene at different heating temperatures. After analyzing and comparing the Raman spectra of spodumene at different temperatures, such as Figure 2 As shown, the color of spodumene gradually becomes lighter. After being heated to more than 1000 degrees, the main peak of α-spodumene disappears at about 703 cm-1, and the main peak of β-spodumene appears at about 489 cm-1. At the same time, the texture of the ore gradually becomes powdery. The intensity of the characteristic peak of β-spodumene is the strongest at 1050°C. It is determined that the temperature corresponding to the best state of spodumene crystal is 1050°C.

[0029] S5: Based on the determined optimal temperature of 1050°C, different time gradients are set, such as Figure 3 As shown in the figure, the Raman spectra of spodumene at different heating times were collected to find the heating time with the best conversion intensity. By comparing and analyzing the Raman spectra at different times, it was found that the Raman characteristic peak intensity was the highest when spodumene was heated for 30 minutes. Figure 4 As shown, when β-spodumene is heated at 1050°C and 30 min, the Raman intensity is the highest, and the optimal crystal transformation temperature and time are determined to be 1050°C and 30 min, thereby realizing rapid detection and process monitoring of spodumene crystal changes.

Claims

1. A method for monitoring ore crystal changes based on Raman spectroscopy, characterized in that Proceed as follows: Ø (1) Sample preparation: Grind the ore in a mortar, sieve out 1-2 mm particles through a sieve, and divide the samples into equal parts; Ø (2) Heating conditions: Place the ore sample in a high-temperature heating container and place it in a muffle furnace to increase the temperature. After the muffle furnace cools down to room temperature, take out the sample; Ø (3) Raman spectroscopy data acquisition: Open the Raman spectroscopy analysis software and laser control software, and use the Raman probe to collect spectra; the Raman spectroscopy data acquisition refers to the laser being emitted by the laser, which is transmitted to the probe via the optical fiber. The probe irradiates the laser onto the ore sample, and the generated Raman scattered light is collected by the probe and then transmitted to the CCD detector of the spectrometer via the incident light optical fiber. The CCD detector converts the optical signal into an electrical signal and transmits it to the data processing system for analysis and processing. Using a Raman spectrometer, by applying laser irradiation to the sample, the Raman scattered light generated is collected, measured and recorded to obtain data that can reflect the molecular structure characteristics of the sample; Ø (4) Data recording and preliminary analysis: Record the Raman spectra of ores with different temperature gradients, conduct preliminary analysis on the collected Raman spectrum data, observe the changes in Raman peak position and intensity, and clarify the relationship between these changes and heating temperature.

2. The method for monitoring ore crystal changes based on Raman spectroscopy technology according to claim 1, wherein the ore refers to lithium ore, quartz, titanium dioxide, calcium carbonate, zirconium oxide, spodumene, aluminum oxide, mica, magnetite, etc.

3. The method for monitoring ore crystal changes based on Raman spectroscopy technology according to claim 2, wherein the lithium ore refers to spodumene and petalite.

4. The method for monitoring ore crystal changes based on Raman spectroscopy technology according to claim 1, wherein observing the changes in Raman peak position and intensity refers to the ore crystal transformation temperature of 500-2500°C, maintaining a constant temperature for a period of time, that is, the transformation time is 15min-60min, and observing the Raman spectrum changes of the ore sample after heating.

5. The method for monitoring ore crystal changes based on Raman spectroscopy technology as described in claim 1, wherein the high-temperature heating temperature in the muffle furnace is 500-2500°C, and after the heating is completed, it is cooled to room temperature and taken out.

6. The method for monitoring ore crystal changes based on Raman spectroscopy technology as described in claim 3, by setting a temperature gradient to heat the lithium ore and measuring its spectrum with the help of a Raman spectrometer, determining the crystal structure changes at different temperatures based on the changes in the peak intensity of the characteristic peak, determining the optimal temperature in combination with the degree, rate and stability of the crystal conversion, and then setting a time gradient at this temperature to measure the spectrum again to determine the crystal change, and determining the optimal time by comprehensively considering the integrity of the crystal conversion, product purity and energy consumption, thereby determining the temperature and time combination parameters of the lithium ore crystal conversion.

7. The method for monitoring ore crystal changes based on Raman spectroscopy technology as described in claim 3, wherein the optimal crystal transformation temperature and time of spodumene β-spodumene are 1050°C and 30 minutes respectively.

8. The method for monitoring ore crystal changes based on Raman spectroscopy technology according to claim 1, wherein the wavelength of the Raman analyzer and the Raman probe used is one of 532nm, 785nm, 830nm or 1064nm, and different wavelengths are selected according to the background fluorescence of the ore. The stronger the fluorescence and the darker the color, the longer the excitation wavelength used.

9. The method for monitoring ore crystal form changes based on Raman spectroscopy technology as described in claim 1, wherein the basis for the crystal form transition is that the Raman spectral characteristic peak of the previous crystal form disappears, a new Raman characteristic peak appears, and a certain regular change occurs with temperature changes.

10. The application of the method for monitoring ore crystal form changes based on Raman spectroscopy technology as described in claim 1 to accurately monitor the ore crystal form transformation process, wherein the accurate monitoring refers to the rapid detection and process monitoring of the ore crystal form transformation.

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