Working method of combined measuring device for acoustoelectric characteristics of multiple metal nodules

Abstract

The invention provides a working method of a combined measurement device for acoustoelectric characteristics of a polymetallic nodule, and provides an integrated measurement device aiming at the limitation of a single physical field measurement technology in traditional deep sea polymetallic nodule research and the problems that an existing method is greatly interfered by the environment and acoustic and electrical characteristics cannot be synchronously obtained. The device synchronously measures the sound velocity, acoustic impedance and acoustic attenuation coefficient of the multi-metal nodule through an ultrasonic transmission method, and measures the surface voltage and resistivity of the multi-metal nodule in combination with a two-pole method and an equivalent conversion model. Synchronous acquisition and analysis of acoustic-electric characteristics are realized, high-precision data support is provided for deep sea mineral resource exploration, mineral component analysis and mining process optimization, and the method can be extensively applied to comprehensive characteristic research of various metal minerals.

Description

Technical Field

[0001] The present invention relates to the technical fields of seabed environment observation and marine engineering geology, and in particular to a working method of a combined measurement device for acoustic and electrical characteristics of polymetallic nodules. Background Art

[0002] Deep-sea polymetallic nodules are mineral resources rich in manganese, iron, nickel, copper, cobalt, and other metals, and are widely distributed in deep-sea basins worldwide. Their composition and structural characteristics are crucial for resource assessment, mining processes, and environmental impact studies. Currently, research on polymetallic nodules relies primarily on deep-sea sampling and laboratory analysis to determine their physical, chemical, and electrical properties.

[0003] Acoustic detection is a key tool in marine resource exploration, leveraging the propagation characteristics of sound waves in different media to identify the distribution of mineral resources and sediments. However, the deep-sea environment is complex, and traditional seabed acoustic detection methods are affected by factors such as water depth, temperature, and pressure, making it difficult to directly analyze the microstructure and material properties of polymetallic nodules. Furthermore, the electrical characteristics of polymetallic nodules, particularly their resistivity, are limited by their irregular shape and current testing equipment, making it impossible to accurately test the resistivity of the nodules.

[0004] In order to more accurately analyze the acoustic and electrical properties of deep-sea polymetallic nodules, the present invention proposes a laboratory measurement device that simultaneously measures the acoustic response, surface voltage, and resistivity characteristics of polymetallic nodules in a controllable environment, providing basic data and experimental support for the exploration, evaluation, and application research of deep-sea resources. Summary of the Invention

[0005] In order to remedy the deficiencies of the prior art, the present invention provides a working method of a combined measurement device for acoustic and electrical characteristics of polymetallic nodules.

[0006] The present invention is achieved through the following technical solutions: a working method of a combined measurement device for the acoustic and electrical characteristics of polymetallic nodules, the device comprising a signal processing and control unit, a threaded adjustment knob, an outer electrical measurement unit, an inner electrical measurement unit, a polymetallic nodule to be measured, an acoustic transmitting unit, an acoustic receiving unit, and a measurement cavity; the signal processing and control unit is internally provided with a voltage / current acquisition module, a battery management module, an acoustic acquisition module, a central processing module, and a data storage module; The polymetallic nodules to be measured are placed inside the measurement cavity. Two inner electrical measurement units are respectively arranged on the left and right sides of the polymetallic nodules to be measured, and two outer electrical measurement units are respectively arranged on the left and right sides of the inner electrical measurement unit. The acoustic transmitting unit and the acoustic receiving unit are respectively installed at the bottom ends of the two outer electrical measurement units. The top ends of the two outer electrical measurement units are provided with threaded adjustment knobs to adjust the depth and angle of the acoustic transmitting unit and the acoustic receiving unit. The outer electrical measurement unit, the inner electrical measurement unit, the acoustic transmitting unit and the acoustic receiving unit are all communicatively connected to the signal processing and control unit. The specific steps include: S1. Sample pretreatment and filling: Clean the surface attachments of the polymetallic nodule sample to be tested, place it in a vacuum drying oven to remove pore moisture, and place the pretreated sample in the center of the titanium alloy measurement cavity; S2. Initialization of the joint measurement system: starting the outer electrical measurement unit, the inner electrical measurement unit, and the signal processing and control unit; S3. Acoustic measurement: Rotate the threaded adjustment knob on the outer electrical measurement unit to fine-tune the depth and angle of the ultrasonic transmitting / receiving probes of the acoustic transmitting unit and the acoustic receiving unit so that they are in close contact with both sides of the polymetallic nodules to be measured. Calculate the sound velocity, acoustic impedance, and acoustic attenuation coefficient based on the ultrasonic transmission method. The sound velocity is the ratio of the path length of the sound wave to the propagation time of the signal from emission to reception. The acoustic impedance is the product of the density of the polymetallic nodule sample and the measured sound velocity. The density of the nodule sample is calculated using the water displacement method. The acoustic attenuation coefficient is calculated using the following formula: in, is the sound attenuation coefficient, is the amplitude of the initial emitted sound wave, is the amplitude of the received sound wave after passing through the polymetallic nodule, and d is the path length; The above formulas are used to obtain the sound velocity, acoustic impedance, and acoustic attenuation coefficient of the sound wave inside the polymetallic nodules, and then to infer the internal structural uniformity, porosity, and mineral composition of the polymetallic nodules. S4. Electrical measurement: First, use the inner electrical measurement unit to test the surface voltage of the polymetallic nodules. Then, remove the polymetallic nodules from the measurement cavity and fill it with homologous polymetallic nodule debris with a particle size of ≤1mm. Fill the cavity evenly using a vibrating compactor. Set electrodes on both sides of the measurement cavity and use the quadrupole method for electrical measurement. The inner electrical measurement unit is used to measure the potential difference, and the spacing between them is 60% of the measurement cavity length. The outer acoustic and electrical combined measurement unit is used to apply current, and the spacing between them is 90% of the measurement cavity length. Based on the measured current and voltage data, calculate the conductivity and resistivity of the polymetallic nodule debris. In addition, to determine the equivalent resistivity of the entire cavity, use the two-pole method, that is, use only two acoustic and electrical combined measurement units for measurement to obtain the equivalent electrical characteristics of the entire cavity. S5. Resistivity equivalent conversion: Based on the equivalent resistivity of the cavity obtained in S4, convert it into the resistivity of the polymetallic nodule using the following formula; The equivalent conductivity of the overall mixture can be expressed as: Taking the logarithm of both ends and expanding them, we get: in, is the equivalent conductivity, The conductivity of the debris can be measured by the quadrupole method when the polymetallic nodules are not placed in the cavity. is the conductivity of the nodule, which is the value to be measured, is the volume fraction of debris, is the cementation index; S6. Combined data analysis and output results: The acoustic velocity, acoustic impedance and acoustic attenuation coefficient are directly calculated by formula, while in the measurement of resistivity, because the equation is nonlinear, It appears in multiple places in the equation, so it needs to be solved by numerical substitution method; Assume that the initial conductivity of the nodule is , assuming that the conductivity of the nodules is the same as that of the debris, substitute into the equation; Calculate new , and then continue the iterative calculation 、 … when Small enough so that the relative error is less than 1%, The iterative calculation results Taking the reciprocal, we can get the resistivity of the nodule; S7: Take multiple measurements to calculate the average value and improve the measurement accuracy.

[0007] As a preferred solution, the measuring cavity is a cubic structure.

[0008] As a preferred solution, the cementation index in step S5 is The value is set to 1.5. After calculating the conductivity, the reciprocal can be directly taken to obtain the resistivity.

[0009] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. This invention integrates an acoustic transmitter / receiver unit with an electrical measurement module to simultaneously collect the acoustic wave propagation characteristics, surface voltage, and resistivity of polymetallic nodules. This approach overcomes the limitations of traditional single-field physical field measurements and provides a new experimental approach for revealing the acoustic-electrical coupling characteristics of polymetallic nodules in complex deep-sea environments, offering significant advantages and innovations.

[0010] 2. This invention incorporates a fixed electrical measurement unit and a mobile combined acoustic and electrical measurement unit that can operate independently or collaboratively. Users can perform resistivity or acoustic property measurements independently, or conduct simultaneous acoustic-electrical coupled testing, enabling comprehensive analysis of the physical properties and internal structure of polymetallic nodules.

[0011] 3. This invention provides a new method for studying the internal structure of polymetallic nodules by simultaneously measuring their acoustic and electrical properties. By coupling acoustic wave propagation with resistivity, it can reveal the microstructural characteristics within the nodules, further advancing our understanding of their formation mechanisms, physical properties, and potential applications.

[0012] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which: Figure 1 It is a structural schematic diagram of the device of the present invention; Figure 2 It is a main structural diagram of the device of the present invention; Figure 3 A top view of the structure of the device of the present invention; Figure 4 This is the internal structure diagram of the signal processing and control unit; Figure 5 A flow chart of the calculation method for the acoustic and electrical characteristics of deep-sea polymetallic nodules; Figure 6 This is the result of continuous testing of the surface voltage of polymetallic nodules. in, Figures 1 to 4 The corresponding relationship between the reference numerals and components is as follows: 1. Signal processing and control unit, 2. Threaded adjustment knob, 3. Outer electrical measurement unit, 5. Inner electrical measurement unit, 4. Polymetallic nodules, 6. Acoustic transmitting unit, 7. Acoustic receiving unit, 8. Voltage / current acquisition module, 9. Battery management module, 10. Acoustic acquisition module, 11. Central processing module, 12. Data storage module, 13. Measurement cavity, 14. Nodule debris. DETAILED DESCRIPTION

[0014] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0015] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0016] The following combination Figures 1 to 4 The working method of the combined measurement device for acoustic and electrical characteristics of polymetallic nodules according to an embodiment of the present invention is described in detail.

[0017] like Figures 1 to 3 As shown, the present invention proposes a working method of a combined measurement device for the acoustic and electrical characteristics of polymetallic nodules. The device for measuring the acoustic and electrical characteristics of polymetallic nodules includes a signal processing and control unit 1, a threaded adjustment knob 2, an outer electrical measurement unit 3, an inner electrical measurement unit 5, a polymetallic nodule to be measured 4, an acoustic transmitting unit 6, an acoustic receiving unit 7, and a measuring cavity 13. The interior of the signal processing and control unit 1 is provided with a voltage / current acquisition module 8, a battery management module 9, an acoustic acquisition module 10, a central processing module 11 and a data storage module 12; the measuring cavity 13 is a cubic structure.

[0018] The polymetallic nodule 4 to be measured is placed within the measurement cavity 13. Two inner electrical measurement units 5 are located on either side of the polymetallic nodule 4, and two outer electrical measurement units 3 are located on either side of the inner electrical measurement unit 5. An acoustic transmitter 6 and an acoustic receiver 7 are mounted at the bottom of each of the two outer electrical measurement units 3. Threaded adjustment knobs 2 are located at the top of each of the two outer electrical measurement units 3 to adjust the depth and angle of the acoustic transmitter 6 and acoustic receiver 7. The outer electrical measurement units 3, the inner electrical measurement unit 5, the acoustic transmitter 6, and the acoustic receiver 7 are all connected to a signal processing and control unit 1, which collects and stores acoustic and electrical data. The screw adjustment knob 2 adjusts the position of the combined acoustic and electrical measurement unit. The acoustic transmitter 6 and acoustic receiver 7 ensure the collection of acoustic and electrical signals.

[0019] like Figure 4 As shown, the signal processing and control unit 1 is the core of the entire device, which can simultaneously receive and store signals from the acoustic unit and the electrical unit. The battery management module 9 is located at the bottom of the signal processing and control unit, which can provide power for all measurement units in the device. The acoustic acquisition module 10, the central processing module 11, and the data storage module 12 jointly collect and process acoustic and electrical data.

[0020] Since the resistivity measurement of this device primarily utilizes the two-pole and four-pole measurement principles, the four-pole method is first used to measure the resistivity of the nodule debris. The two inner electrical measurement units are primarily used to measure the potential difference, avoiding measurement errors caused by contact resistance or cable resistance. The outer acoustic and electrical measurement units, on the other hand, apply current to ensure that it flows evenly throughout the cavity. The two outer acoustic and electrical measurement units are then used to measure the equivalent resistivity of the cavity and convert the equivalent resistivity.

[0021] The specific steps include: S1. Sample pretreatment and filling: Clean the surface attachments of the polymetallic nodule 4 sample to be tested, place it in a vacuum drying oven to remove pore moisture, and place the pretreated sample in the center of the titanium alloy measurement cavity; S2, initialization of the joint measurement system: starting the outer electrical measurement unit 3, the inner electrical measurement unit 5, and the signal processing and control unit 1; S3. Acoustic measurement: Rotate the threaded adjustment knob 2 on the outer electrical measurement unit 3 to fine-tune the depth and angle of the ultrasonic transmitting / receiving probes of the acoustic transmitting unit 6 and the acoustic receiving unit 7 so that they are in close contact with both sides of the polymetallic nodule 4 to be measured; by optimizing the fit of the probes, ensure that the acoustic wave signal can smoothly pass through the central cavity of the nodule, thereby improving signal stability and measurement accuracy. This device is based on the ultrasonic transmission method to calculate the sound velocity, acoustic impedance, and acoustic attenuation coefficient; the sound velocity is the ratio of the path length of the sound wave to the propagation time of the signal from emission to reception; the acoustic impedance is the product of the density of the polymetallic nodule sample and the measured sound velocity. The density of the nodule sample is calculated according to the water displacement method; the acoustic attenuation coefficient is calculated according to the following formula: in, is the sound attenuation coefficient, is the amplitude of the initial emitted sound wave, is the amplitude of the received sound wave after passing through the polymetallic nodule, and d is the path length; The above formulas are used to obtain the sound velocity, acoustic impedance, and acoustic attenuation coefficient of the sound wave inside the polymetallic nodules, and then to infer the internal structural uniformity, porosity, and mineral composition of the polymetallic nodules. S4. Electrical measurement: First, use the inner electrical measurement unit 5 to test the surface voltage of the polymetallic nodules. Then, remove the polymetallic nodules from the measurement cavity and fill them with homologous polymetallic nodule debris with a particle size of ≤1 mm. Use a vibrating compaction device to uniformly fill the cavity to ensure a stable filling density. Electrodes are set on both sides of the measurement cavity, and the quadrupole method is used for electrical measurement. The inner electrical measurement unit is used to measure the potential difference, and the spacing between them is 60% of the measurement cavity length. The outer acoustic and electrical combined measurement unit is used to apply current, and the spacing between them is 90% of the measurement cavity length. Based on the measured current and voltage data, the conductivity and resistivity of the polymetallic nodule debris are calculated. In addition, to determine the equivalent resistivity of the entire cavity, the two-pole method is used, that is, only two acoustic and electrical combined measurement units are used for measurement to obtain the equivalent electrical characteristics of the entire cavity. S5. Resistivity equivalent conversion: Based on the equivalent resistivity of the cavity obtained in S4, convert it into the resistivity of the polymetallic nodule using the following formula; The equivalent conductivity of the overall mixture can be expressed as: Taking the logarithm of both ends and expanding them, we get: in, is the equivalent conductivity, The conductivity of the debris can be measured by the quadrupole method when the polymetallic nodules are not placed in the cavity. is the conductivity of the nodule, which is the value to be measured, is the volume fraction of debris, is the cementation index; considering that the nodule debris is a spherical particle, the contact surface between particles is small due to the geometric shape of the spherical particles, so the cementation index in step S5 is The value is set to 1.5. After calculating the conductivity, the reciprocal can be directly taken to obtain the resistivity.

[0022] S6. Combined data analysis and output results: The acoustic velocity, acoustic impedance and acoustic attenuation coefficient are directly calculated by formula, while in the measurement of resistivity, because the equation is nonlinear, It appears in multiple places in the equation, so it needs to be solved by numerical substitution method; Assume that the initial conductivity of the nodule is , assuming that the conductivity of the nodules is the same as that of the debris, substitute into the equation; Calculate new , and then continue the iterative calculation 、 … when Small enough so that the relative error is less than 1%, The iterative calculation results Taking the reciprocal, we can get the resistivity of the nodule; S7: Take multiple measurements to calculate the average value and improve the measurement accuracy.

[0023] In the description of the present invention, the term "plurality" refers to two or more than two. Unless otherwise expressly defined, the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limitations on the present invention. The terms "connect," "install," and "fix" should all be understood in a broad sense. For example, "connection" can mean a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0025] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for operating a combined measurement device for acoustic and electrical characteristics of polymetallic nodules, characterized in that The device for measuring the acoustic and electrical characteristics of polymetallic nodules comprises a signal processing and control unit (1), a threaded adjustment knob (2), an outer electrical measurement unit (3), an inner electrical measurement unit (5), a polymetallic nodule to be measured (4), an acoustic transmitting unit (6), an acoustic receiving unit (7), and a measuring cavity (13). The signal processing and control unit (1) is internally provided with a voltage / current acquisition module (8), a battery management module (9), an acoustic acquisition module (10), a central processing module (11), and a data storage module (12); The polymetallic nodules (4) to be measured are placed inside the measuring cavity (13), two inner electrical measuring units (5) are respectively arranged on the left and right sides of the polymetallic nodules (4) to be measured, two outer electrical measuring units (3) are respectively arranged on the left and right sides of the inner electrical measuring unit (5), the acoustic transmitting unit (6) and the acoustic receiving unit (7) are respectively installed at the bottom ends of the two outer electrical measuring units (3), the top ends of the two outer electrical measuring units (3) are respectively provided with threaded adjustment knobs (2) for adjusting the depth and angle of the acoustic transmitting unit (6) and the acoustic receiving unit (7), and the outer electrical measuring unit (3), the inner electrical measuring unit (5), the acoustic transmitting unit (6) and the acoustic receiving unit (7) are all communicatively connected to the signal processing and control unit (1); The specific steps include: S1. Sample pretreatment and filling: clean the surface attachments of the polymetallic nodule (4) sample to be tested, place it in a vacuum drying oven to remove pore moisture, and place the pretreated sample in the center of the titanium alloy measurement cavity; S2, initialization of the joint measurement system: starting the outer electrical measurement unit (3), the inner electrical measurement unit (5), and the signal processing and control unit (1); S3. Acoustic measurement: Rotate the threaded adjustment knob (2) on the outer electrical measurement unit (3) to fine-tune the depth and angle of the ultrasonic transmitting / receiving probes of the acoustic transmitting unit (6) and the acoustic receiving unit (7) so that they are in close contact with both sides of the polymetallic nodule (4) to be measured; calculate the sound velocity, acoustic impedance and acoustic attenuation coefficient based on the ultrasonic transmission method; the sound velocity is the ratio of the path length of the sound wave to the propagation time of the signal from emission to reception; the acoustic impedance is the product of the density of the polymetallic nodule sample and the measured sound velocity, and the density of the nodule sample is calculated according to the water displacement method; the acoustic attenuation coefficient is calculated according to the following formula: in, is the sound attenuation coefficient, is the amplitude of the initial emitted sound wave, is the amplitude of the received sound wave after passing through the polymetallic nodule, and d is the path length; The above formulas are used to obtain the sound velocity, acoustic impedance, and acoustic attenuation coefficient of the sound wave inside the polymetallic nodules, and then to infer the internal structural uniformity, porosity, and mineral composition of the polymetallic nodules. S4. Electrical measurement: First, use the inner electrical measurement unit (5) to test the surface voltage of the polymetallic nodules, then remove the polymetallic nodules from the measurement cavity and fill them with polymetallic nodule debris of the same origin with a particle size of ≤1mm, and fill them evenly with a vibration compaction device; set electrodes on both sides of the measurement cavity, and use the quadrupole method to perform electrical measurement, wherein the inner electrical measurement unit is used to measure the potential difference, and the spacing between them is 60% of the measurement cavity length, and the outer acoustic and electrical combined measurement unit is used to apply current, and the spacing between them is 90% of the measurement cavity length; based on the measured current and voltage data, calculate the conductivity and resistivity of the polymetallic nodule debris; in addition, to determine the equivalent resistivity of the entire cavity, a two-pole method is used, that is, only two acoustic and electrical combined measurement units are used for measurement to obtain the equivalent electrical characteristics of the entire cavity; S5. Resistivity equivalent conversion: Based on the equivalent resistivity of the cavity obtained in S4, convert it into the resistivity of the polymetallic nodule using the following formula; The equivalent conductivity of the overall mixture can be expressed as: Taking the logarithm of both ends and expanding them, we get: in, is the equivalent conductivity, The conductivity of the debris can be measured by the quadrupole method when the polymetallic nodules are not placed in the cavity. is the conductivity of the nodule, which is the value to be measured, is the volume fraction of debris, is the cementation index; S6. Combined data analysis and output results: The acoustic velocity, acoustic impedance and acoustic attenuation coefficient are directly calculated by formula, while in the measurement of resistivity, because the equation is nonlinear, It appears in multiple places in the equation, so it needs to be solved by numerical substitution method; Assume that the initial conductivity of the nodule is , assuming that the conductivity of the nodules is the same as that of the debris, substitute into the equation; Calculate new , and then continue the iterative calculation 、 … when Small enough so that the relative error is less than 1%, The iterative calculation results Taking the reciprocal, we can get the resistivity of the nodule; S7: Take multiple measurements to calculate the average value and improve the measurement accuracy.

2. The working method of the combined measurement device for acoustic and electrical characteristics of polymetallic nodules according to claim 1 is characterized in that , the measuring cavity (13) is a cubic structure.

3. The working method of the combined measurement device for acoustic and electrical characteristics of polymetallic nodules according to claim 1 is characterized in that , the cementation index in step S5 The value is set to 1.

5. After calculating the conductivity, the reciprocal can be directly taken to obtain the resistivity.

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