Method for operating a combined measuring device for the acoustic-electric characteristics of a polymetallic nodule

Abstract

The application provides a working method of a combined measurement device for the acoustic and electric characteristics of a polymetallic nodule, and aims at the limitation of a single physical field measurement technology in the traditional deep-sea polymetallic nodule research, and the problems that the existing method is greatly disturbed by the environment and cannot synchronously acquire acoustic and electric characteristics. The application provides an integrated measurement device. The device synchronously measures the sound velocity, acoustic impedance and acoustic attenuation coefficient of the polymetallic nodule through an ultrasonic transmission method, and measures the surface voltage and resistivity of the polymetallic nodule by combining a two-pole method and an equivalent conversion model. The synchronous acquisition and analysis of the acoustic and electric characteristics are realized, high-precision data support is provided for the deep-sea mineral resource exploration, mineral composition analysis and mining process optimization, and the application can be extended to the comprehensive characteristic research of various metal minerals.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seabed environment observation and the technical field of marine engineering geology, in particular, particularly relates to a kind of working method of the joint measurement device of the acoustic and electric characteristics of polymetallic nodule. BACKGROUND

[0002] Deep-sea polymetallic nodule is a kind of mineral resources rich in manganese, iron, nickel, copper, cobalt and other metal elements, widely distributed in global deep-sea basin. Its composition and structural characteristics are of great significance to resource assessment, mining technology and environmental impact study. At present, the research on polymetallic nodule mainly relies on deep-sea sampling and laboratory analysis to obtain its physical, chemical and electrical properties.

[0003] Acoustic detection is one of the important means of marine resource exploration, which can identify the distribution of mineral resources and sediments by using the propagation characteristics of sound waves in different media. However, the deep-sea environment is complex, and the traditional seabed acoustic detection method is affected by water depth, temperature, pressure and other factors, making it difficult to directly analyze the microstructure and material properties of polymetallic nodule. In addition, for the electrical characteristics of polymetallic nodule, especially its resistivity, due to its irregular shape and current testing device, the resistivity of the nodule cannot be accurately tested.

[0004] In order to more accurately analyze the acoustic and electrical properties of deep-sea polymetallic nodule, the present application provides a laboratory measuring device, which synchronously measures the acoustic response, surface voltage and resistivity characteristics of polymetallic nodule in a controllable environment, providing basic data and experimental support for the exploration, evaluation and application research of deep-sea resources. SUMMARY

[0005] In order to make up for the shortcomings of the prior art, the present application provides a working method of a joint measurement device of acoustic and electric characteristics of polymetallic nodule.

[0006] The present application is realized by the following technical scheme: a working method of a joint measurement device of acoustic and electric characteristics of polymetallic nodule, the measurement device of acoustic and electric characteristics of polymetallic nodule includes signal processing and control unit, screw adjusting knob, outer electrical measurement unit, inner electrical measurement unit, to-be-measured polymetallic nodule, acoustic emission unit, acoustic receiving unit, measuring cavity, the inside of signal processing and control unit is provided with voltage / current acquisition module, battery management module, acoustic acquisition module, central processing module and data storage module;

[0007] The measured cavity is internally placed with a multi-metallic nodule to be measured, the internal electrical measurement unit has a total of 2 and is respectively arranged on the left and right sides of the multi-metallic nodule to be measured, the external electrical measurement unit has a total of 2 and is respectively arranged on the left and right sides of the internal electrical measurement unit, the acoustic emission unit and the acoustic receiving unit are respectively installed at the bottom end of the two external electrical measurement units, the top end of the two external electrical measurement units is provided with a threaded adjusting knob for adjusting the depth and angle of the acoustic emission unit and the acoustic receiving unit, and the external electrical measurement unit, the internal electrical measurement unit, the acoustic emission unit and the acoustic receiving unit are all communicatively connected to the signal processing and control unit;

[0008] Specifically, the following steps are included:

[0009] S1, sample pretreatment and filling: the surface attachments of the multi-metallic nodule sample to be measured are cleaned, placed in a vacuum drying box to remove pore moisture, and the pretreated sample is placed in the center of the titanium alloy measurement cavity;

[0010] S2, initialization of the combined measurement system: start the external electrical measurement unit, the internal electrical measurement unit and the signal processing and control unit;

[0011] S3, acoustic measurement: rotate the threaded adjusting knob on the external electrical measurement unit, and finely adjust the depth and angle of the ultrasonic wave emission / receiving probe of the acoustic emission unit and the acoustic receiving unit to tightly adhere to the two sides of the multi-metallic nodule to be measured; based on the ultrasonic transmission method, the sound velocity, acoustic impedance and acoustic attenuation coefficient are calculated; the sound velocity is the ratio of the path length of the sound wave passing through to the propagation time of the signal from emission to reception; the acoustic impedance is the product of the density of the multi-metallic nodule sample and the measured sound velocity, and the density of the nodule sample is calculated according to the drainage method; the acoustic attenuation coefficient is calculated according to the following formula:

[0012]

[0013] wherein, is the acoustic attenuation coefficient, is the amplitude of the initial emitted sound wave, is the amplitude of the received sound wave after passing through the multi-metallic nodule, and d is the path length;

[0014] Through the above formula, the sound velocity, acoustic impedance and acoustic attenuation coefficient of the sound wave in the multi-metallic nodule are obtained, and the internal structure uniformity, porosity and mineral composition of the multi-metallic nodule are further inferred;

[0015] S4, electrical measurement: first, use the inner electrical measurement unit to test the surface voltage of the polymetallic nodule, then take out the polymetallic nodule in the measurement cavity, and fill the same polymetallic nodule debris with a particle size of ≤1 mm, and uniformly fill it through the vibration compaction device; electrodes are arranged on both sides of the measurement cavity, and a four-pole method is used for electrical measurement, wherein the inner electrical measurement unit is used to measure the potential difference, and the distance is 60% of the length of the measurement cavity; the outer acoustic and electrical combined measurement unit is used to apply current, and the distance is 90% of the length of the measurement cavity; based on the measured current and voltage data, the conductivity and resistivity of the polymetallic nodule debris are calculated; in addition, in order to determine the equivalent resistivity of the whole 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 properties of the whole cavity;

[0016] S5, resistivity equivalent transformation: according to the equivalent resistivity of the cavity obtained in S4, it is transformed into the resistivity of the polymetallic nodule by the following formula;

[0017] Where the equivalent conductivity expression of the whole mixture is:

[0018]

[0019] Take the logarithm of both ends at the same time, and expand to get:

[0020]

[0021] Where, is the equivalent conductivity, is the conductivity of the debris, and the conductivity of the nodule debris is measured by the four-pole method when the polymetallic nodule is not put into the cavity, is the conductivity of the nodule, which is the value to be measured, is the volume fraction of the debris, is the cementation index;

[0022] S6, joint data analysis, output results: the acoustic velocity, acoustic impedance and acoustic attenuation coefficient are directly calculated by the formula, and in the measurement of the resistivity, Because the equation is nonlinear,

[0023] Assume that the initial value of the conductivity of the nodule is That is, the conductivity of the nodule is the same as that of the debris, which is substituted into Equation;

[0024] Calculate the new Then continue to iterate , …

[0025] When small enough that the relative error is less than 1%,

[0026] Taking the reciprocal of the obtained resistivity of the nodule can be obtained;

[0027] S7: multiple measurements are averaged to improve measurement accuracy.

[0028] As a preferred solution, the measurement cavity is a cubic structure.

[0029] As a preferred solution, the cementation index in step S5 is 1.5, and the resistivity is obtained by directly taking the reciprocal of the conductivity after calculation.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] 1. The present application realizes the synchronous acquisition of the acoustic wave propagation characteristics, surface voltage and resistivity of the polymetallic nodule by integrating the acoustic emission / receiving unit and the electrical measurement module. This solution breaks through the limitations of traditional single physical field measurement, provides a new experimental method for revealing the acoustic-electric coupling characteristics of the polymetallic nodule in a complex deep-sea environment, and has significant advantages and innovation.

[0032] 2. The present application designs a fixed electrical measurement unit and a movable acoustic and electrical combined measurement unit that can work independently or cooperatively. Users can measure the resistivity or acoustic characteristics independently according to their needs, or perform acoustic-electric coupling tests simultaneously, thereby comprehensively analyzing the physical characteristics and internal structure of the polymetallic nodule.

[0033] 3. The present application provides a new means for studying the internal structure of the polymetallic nodule by synchronously measuring its acoustic and electrical characteristics. Through the coupling analysis of acoustic wave propagation and resistivity, the microstructure characteristics of the nodule can be revealed, further promoting the in-depth understanding of the formation mechanism, physical properties and potential applications of the polymetallic nodule.

[0034] Additional aspects and advantages of the present application will become apparent from the following description section, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0035] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0036] Figure 1 is a structural diagram of the device of the present application;

[0037] Figure 2 is a front view structural diagram of the device of the present application;

[0038] Figure 3 is a top view of the device of the present application;

[0039] Figure 4 is an internal structure diagram of the signal processing and control unit;

[0040] Figure 5 is a flow chart of the calculation method of the acoustoelectric characteristics of the deep-sea polymetallic nodule;

[0041] Figure 6 is a result diagram of the surface voltage of the polymetallic nodule in continuous testing,

[0042] wherein, Figures 1 to 4 the correspondence between the reference signs and the components is as follows:

[0043] 1 signal processing and control unit, 2 threaded adjustment knob, 3 outer electrical measurement unit, 5 inner electrical measurement unit, 4 polymetallic nodule, 6 acoustic emission 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

[0044] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0045] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other different ways from those described herein, therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0046] The working method of the joint measurement device of the acoustoelectric characteristics of the polymetallic nodule of the embodiments of the present application will be described in detail below. Figures 1 to 4 The working method of the joint measurement device of the acoustoelectric characteristics of the polymetallic nodule of the embodiments of the present application will be described in detail below.

[0047] As Figures 1 to 3 shown, the present application proposes a working method of a joint measurement device of the acoustoelectric characteristics of the polymetallic nodule, the measurement device of the acoustoelectric characteristics of the polymetallic nodule 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 to-be-measured polymetallic nodule 4, an acoustic emission unit 6, an acoustic receiving unit 7, a measurement cavity 13, and 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 measurement cavity 13 is a cubic structure.

[0048] The inside of the measuring cavity 13 is placed with the multi-metallic nodule 4 to be measured, the inside electrical measurement unit 5 has two units respectively arranged on the left and right sides of the multi-metallic nodule 4 to be measured, the outside electrical measurement unit 3 has two units respectively arranged on the left and right sides of the inside electrical measurement unit 5, the acoustic emission unit 6 and the acoustic receiving unit 7 are respectively installed at the bottom ends of the two outside electrical measurement units 3, the top ends of the two outside electrical measurement units 3 are respectively provided with the screw adjusting knob 2 for adjusting the depth and angle of the acoustic emission unit 6 and the acoustic receiving unit 7, and the outside electrical measurement unit 3, the inside electrical measurement unit 5, the acoustic emission unit 6 and the acoustic receiving unit 7 are all in communication connection with the signal processing and control unit 1; the signal processing and control unit 1 can collect and store acoustic and electrical data. The screw adjusting knob 2 can adjust the position of the acoustic and electrical combined measurement unit, and the acoustic emission unit 6 and the acoustic receiving unit 7 ensure the collection of acoustic and electrical signals.

[0049] As shown in Figure 4 The signal processing and control unit 1 is the core of the whole device, which can simultaneously receive and store the signals of the acoustic unit and the electrical unit, wherein the battery management module 9 is located at the bottom of the signal processing and control unit, which can provide power supply for all the measurement units in the device, and the acoustic acquisition module 10, the central processing module 11 and the data storage module 12 jointly collect and process acoustic and electrical data.

[0050] Since the resistivity measurement of the device mainly adopts the measurement principles of two-stage method and four-pole method, the four-pole method is first used to measure the resistivity of the nodule debris, and the two inside electrical measurement units are mainly used to measure the potential difference to avoid measurement errors caused by contact resistance or cable resistance. The outside acoustic and electrical measurement units are used to apply current to make the current uniformly pass through the whole cavity. Then, the two outside acoustic and electrical measurement units are used to measure the equivalent resistivity of the cavity and convert the equivalent resistivity.

[0051] Specifically, the following steps are included:

[0052] S1, sample pretreatment and filling: the surface attachments of the multi-metallic nodule 4 sample to be measured are cleaned, placed in a vacuum drying box to remove pore water, and the pretreated sample is placed in the center of the titanium alloy measuring cavity;

[0053] S2, initialization of the combined measurement system: starting the outside electrical measurement unit 3, the inside electrical measurement unit 5 and the signal processing and control unit 1;

[0054] S3, acoustic measurement: rotate the screw knob 2 on the outer side of the electrical measurement unit 3, fine-tune the depth and angle of the ultrasonic transmitting / receiving probe of the acoustic transmitting unit 6 and the acoustic receiving unit 7 to closely fit the two sides of the multi-metal nodule 4 to be measured; by optimizing the fitting degree of the probe, it is ensured that the acoustic signal can smoothly pass through the center cavity of the nodule, thereby improving the stability and measurement accuracy of the signal. The device is based on 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 from transmission to reception; the acoustic impedance is the product of the density of the multi-metal nodule sample and the measured sound velocity, and the density of the nodule sample is calculated according to the drainage method; the acoustic attenuation coefficient is calculated according to the following formula:

[0055]

[0056] wherein, is the acoustic attenuation coefficient, is the amplitude of the initial transmitted acoustic wave, is the amplitude of the received acoustic wave after passing through the multi-metal nodule, and d is the path length;

[0057] Through the above formula, the sound velocity, acoustic impedance and acoustic attenuation coefficient of the acoustic wave inside the multi-metal nodule are obtained, and the internal structure uniformity, porosity and mineral composition of the multi-metal nodule are inferred;

[0058] S4, electrical measurement: first, use the inner electrical measurement unit 5 to test the surface voltage of the multi-metal nodule, then take out the multi-metal nodule in the measurement cavity and fill it with homologous multi-metal nodule debris with a particle size of ≤1mm, uniformly fill it through the vibration compaction device to ensure stable filling density; electrodes are arranged on both sides of the measurement cavity, and four-pole method is used for electrical measurement, wherein the inner electrical measurement unit is used to measure the potential difference, and the distance between them is 60% of the length of the measurement cavity; the outer acoustic and electrical combined measurement unit is used to apply current, and the distance between them is 90% of the length of the measurement cavity; based on the measured current and voltage data, the conductivity and resistivity of the multi-metal nodule debris are calculated; in addition, in order to determine the equivalent resistivity of the whole cavity, two-pole method is used, that is, only two acoustic and electrical combined measurement units are used for measurement to obtain the equivalent electrical properties of the whole cavity;

[0059] S5, resistivity equivalent conversion: according to the equivalent resistivity of the cavity obtained in S4, it is converted into the resistivity of the multi-metal nodule through the following formula;

[0060] wherein the equivalent conductivity expression of the whole mixture is:

[0061]

[0062] Take the logarithm of both ends at the same time and expand to get:

[0063]

[0064] wherein, is the equivalent conductivity, is the conductivity of the detritus, which is measured by the quadrupole method when the polymetallic nodule is not put into the cavity, is the conductivity of the nodule, which is the measured value, is the volume fraction of the detritus, is the cementation index; wherein, considering the spherical particle characteristics of the nodule detritus, since the geometric shape of the spherical particles makes the contact surface between the particles small, the cementation index in step S5 is set to 1.5, and the resistivity is obtained by directly taking the reciprocal of the conductivity after calculation.

[0065] S6, joint data analysis, output results: sound speed, acoustic impedance and acoustic attenuation coefficient are directly calculated by formula, and in the measurement of resistivity, because the equation is nonlinear, appears in multiple positions of the equation, so it needs to be solved by numerical selection method;

[0066] Assume that the initial value of the conductivity of the nodule is , that is, the conductivity of the nodule is the same as that of the detritus, which is substituted into to the equation;

[0067] Calculate the new , and then continue to perform iterative calculation , …

[0068] When is small enough, the relative error is less than 1%,

[0069] Take the reciprocal of the obtained by iterative calculation, that is, the resistivity of the nodule can be obtained;

[0070] S7: multiple measurements to obtain the average value to improve the measurement accuracy.

[0071] ​In the description of the application, the term "a plurality" refers to two or more, unless otherwise specifically defined, the terms "upper", "lower" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application; the terms "connection", "installation", "fixation" and the like should be understood broadly, for example, "connection" can be fixed connection, or detachable connection, or integral connection; can be directly connected, or indirectly connected through intermediate media. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0072] In the description of the present application, the terms "one embodiment", "some embodiments", "a specific embodiment" and the like are intended to mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0073] The above is only the preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of operating a combined measuring device of acoustic electric characteristics of poly-metallic nodule, characterized in that The device for measuring the electroacoustic characteristics of the polymetallic nodule comprises a signal processing and control unit (1), a screw adjusting knob (2), an outer electrical measurement unit (3), an inner electrical measurement unit (5), a polymetallic nodule to be measured (4), an acoustic emission unit (6), an acoustic receiving unit (7), and a measurement 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 nodule to be measured (4) is placed inside the measurement cavity (13), the inner electrical measurement unit (5) is provided with two units respectively arranged on the left and right sides of the polymetallic nodule to be measured (4), the outer electrical measurement unit (3) is provided with two units respectively arranged on the left and right sides of the inner electrical measurement unit (5), the acoustic emission unit (6) and the acoustic receiving unit (7) are respectively installed at the bottom ends of the two outer electrical measurement units (3), the screw adjusting knobs (2) are arranged at the top ends of the two outer electrical measurement units (3) to adjust the depth and angle of the acoustic emission unit (6) and the acoustic receiving unit (7), and the outer electrical measurement unit (3), the inner electrical measurement unit (5), the acoustic emission unit (6), and the acoustic receiving unit (7) are all in communication connection with the signal processing and control unit (1); Specifically comprising the following steps: S1, sample pretreatment and filling: the surface attachments of the polymetallic nodule sample to be measured (4) are cleaned, the sample is placed in a vacuum drying box to remove pore water, and the pretreated sample is placed in the center of the titanium alloy measurement cavity; S2, initialization of the combined measurement system: the outer electrical measurement unit (3), the inner electrical measurement unit (5), and the signal processing and control unit (1) are started; S3, acoustic measurement: the screw adjusting knob (2) on the outer electrical measurement unit (3) is rotated to finely adjust the depth and angle of the ultrasonic emission / receiving probe of the acoustic emission unit (6) and the acoustic receiving unit (7) so that they are tightly attached to the two sides of the polymetallic nodule to be measured (4); based on the ultrasonic transmission method, the sound velocity, acoustic impedance, and acoustic attenuation coefficient are calculated; the sound velocity is the ratio of the path length of the sound wave to the propagation time 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 drainage method; the acoustic attenuation coefficient is calculated according to the following formula: wherein, is the sound attenuation coefficient, is the amplitude of the initial transmitted sound wave, is the amplitude of the received sound wave after passing through the multi-metal nodule, d is the path length; Through the above formula, the sound velocity, acoustic impedance, and acoustic attenuation coefficient of the sound wave inside the polymetallic nodule are obtained, and the internal structure uniformity, porosity, and mineral composition of the polymetallic nodule are inferred. S4, electrical measurement: first, use the inner electrical measurement unit (5) to test the surface voltage of the polymetallic nodule, then take out the polymetallic nodule in the measurement cavity, and fill the same polymetallic nodule debris with a particle size of ≤1mm, and uniformly fill it through the vibration compaction device; electrodes are arranged on both sides of the measurement cavity, and four-pole method is used for electrical measurement, wherein the inner electrical measurement unit is used to measure the potential difference, and the distance is 60% of the length of the measurement cavity; the outer acoustic and electrical combined measurement unit is used to apply current, and the distance is 90% of the length of the measurement cavity; based on the measured current and voltage data, the conductivity and resistivity of the polymetallic nodule debris are calculated; in addition, in order to determine the equivalent resistivity of the whole cavity, two-pole method is used, that is, only two acoustic and electrical combined measurement units are used for measurement, and the equivalent electrical characteristics of the whole cavity are obtained; S5, resistivity equivalent transformation: according to the equivalent resistivity of the cavity obtained in S4, it is transformed into the resistivity of the polymetallic nodule through the following formula; Wherein the equivalent conductivity expression of the whole mixture is: Take the logarithm of both ends at the same time, and expand to get: wherein, Gc is the equivalent conductivity, Gd is the conductivity of the detritus, measured by the quadrupole method when the polymetallic nodule is not placed in the chamber, Gn is the conductivity of the nodule, which is the value to be measured, φd is the volume fraction of the detritus, Gc is the cementation index; S6, combined data analysis, output results: sound velocity, acoustic impedance and acoustic attenuation coefficient are calculated directly by formula, while the measurement of resistivity, because the equation is nonlinear, appears in multiple locations in the equation, so it needs to be solved by numerical methods. Assume that the initial value of the conductivity of the nodule is i.e. assume that the conductivity of the nodule is the same as the conductivity of the debris, substitute into the equation; Compute new Then continue with the iterative computation , … When small enough that the relative error is less than 1%, The resistivity of the tubercle is obtained by taking the reciprocal of the result of the iterative calculation Taking the reciprocal, the resistivity of the tubercle is obtained; S7: multiple measurements to improve measurement accuracy.

2. The method of operation of a device for combined measurement of acoustic and electric characteristics of poly-metallic nodule according to claim 1, characterized in that The measurement cavity (13) is a cubic structure.

3. The method of operating a device for combined measurement of acoustic and electric properties of a multi-metallic nodule according to claim 1, characterized in that , the cementation index in the step S5 is set as 1.5, and the resistivity is obtained by directly taking the inverse of the conductivity after the conductivity is calculated. value of 1.5, and the resistivity is obtained by directly taking the inverse of the conductivity after the conductivity is calculated.

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