Device and method for measuring concentration and granularity of deep-sea mining ore pulp

Abstract

The deep-sea mining pulp concentration and granularity measuring device comprises a main pipeline and an optical detection unit, a branch pipeline is arranged on the main pipeline, the optical detection unit comprises a light source and an image acquisition module arranged corresponding to the light source, and the light source and the image acquisition module are located on the two sides of the branch pipeline respectively; an array type ultrasonic sensor is further arranged on the main pipeline; and the image acquisition module and the array type ultrasonic sensor are connected with the control system. According to the invention, the concentration and granularity information of particles coexisting in three-phase media of tuberculosis particles, sediment particles and seawater is measured in a combined manner by adopting a plurality of measurement modes combining ultrasonic wave, light scattering and image methods, the detection accuracy is high, and the concentration (particle volume fraction) and granularity information of particles in ore pulp can be detected at the same time; the detection result is high in accuracy and the detection speed is high.

Description

Technical Field

[0001] The present invention relates to the technical field of slurry flow and concentration detection, and in particular to a device and method for measuring slurry flow and concentration in deep-sea mining. Background Art

[0002] Deep-sea mining is the collection of mineral resources from the seafloor, including polymetallic nodules, sulfide deposits and cobalt-rich crusts. In the process of deep-sea mining, a large amount of seafloor sediments and other materials are processed, and the mixture produced in this process is usually called "slurry". Slurry is a fluid substance formed by mixing the mined nodule particles, sediment particles, etc. with seawater, which is convenient for transportation to surface ships or processing facilities on land through pipelines.

[0003] When the slurry is collected and transported to the processing station through a pipeline, the particle concentration (i.e., particle volume fraction) and particle size in the slurry need to be tested.

[0004] Existing detection methods mostly use acoustic measurement methods for detection, which mostly focus on the concentration of single-phase fluid media or monodisperse particle flow, but cannot distinguish between seawater, nodule particles, and sediment particles. Ultrasonic methods can measure particle sizes from nanometers to millimeters, which is suitable for measuring sediments. However, when the nodule particle size reaches the centimeter level, the particles have a greater attenuation effect on ultrasound, and the ultrasonic signal is greatly attenuated, resulting in inaccurate measurement results.

[0005] In deep-sea mining environments, the volume fraction of particles in the slurry is high, the average spacing between nodules is close to the order of magnitude of the particle size, and the multiple scattering and inter-particle coupling effects are very significant; the collected nodule particles can reach several centimeters in diameter, while the associated sediment particles may be only tens of microns or even smaller; this wide particle size range and multi-peak distribution poses a great challenge to ultrasonic measurement. Traditional ultrasonic measurement methods are often unable to effectively meet the measurement requirements of slurries with such a wide particle size range and multi-peak distribution.

[0006] Therefore, there is an urgent need to provide a deep-sea mining slurry concentration and particle size measurement device and method, which can quickly and accurately detect the concentration and particle size of particulate matter in the slurry to meet the operational needs of deep-sea mining. Summary of the invention

[0007] The purpose of the present invention is to solve the deficiencies in the prior art and to provide a device and method for measuring slurry concentration and particle size in deep-sea mining.

[0008] The objective of the present invention is achieved through the following technical scheme: a deep-sea mining slurry concentration and particle size measuring device, comprising a main pipeline and an optical detection unit, a branch pipeline is arranged on the main pipeline, the optical detection unit comprises a light source and an image acquisition module arranged corresponding to the light source, the light source and the image acquisition module are respectively located on both sides of the branch pipeline; an array ultrasonic sensor is also arranged on the main pipeline; the image acquisition module and the array ultrasonic sensor are both connected to the control system.

[0009] Preferably, a temperature sensor and a pressure sensor are also provided on the main pipeline.

[0010] Preferably, the image acquisition module comprises an image sensor and a multispectral camera.

[0011] Preferably, a dilution pipeline is provided on the branch pipeline, and the dilution pipeline is used to introduce water into the branch pipeline and dilute the slurry in proportion.

[0012] A method for measuring the concentration and particle size of a deep-sea mining slurry. When detecting the concentration of particles in the slurry, the specific method is as follows: S1: The array ultrasonic sensor emits ultrasonic pulses, which pass through the slurry in the branch pipe. The sound velocity of the ultrasonic pulse signal is obtained through the receiving end of the array ultrasonic sensor. Sound attenuation coefficient , and calculate the experimental complex wave number; S2: setting the particle concentration to Φ, setting the initial value of Φ, and calculating the theoretical complex wave number related to the particle concentration Φ; S3: Compare the theoretical complex wave number with the experimental complex wave number and calculate the target error related to the particle concentration Φ ; Set the target error threshold and adjust the value of Φ; when the target error When it is less than or equal to the target error threshold, the value of Φ is the measured value of the particle concentration; The particles in the slurry include nodule particles and sediment particles. When detecting the particle size of nodule particles in the slurry, the multispectral camera in the optical detection unit is used to perform backlight imaging on the nodule particles in the branch pipe, and the projection profile of the nodule particles is obtained to analyze the particle size of the nodule particles; and the probability of random distribution of particles at the detection position is described by Poisson distribution; When detecting the particle size of sediment particles in the slurry, the multi-band extinction imaging method is used for measurement. The Levenberg–Marquardt data inversion algorithm is used to represent the overall detection data as a weighted superposition of the contributions of nodule particles and sediment particles. The least squares method is then used to fit the model to obtain the particle size distribution of nodule particles and sediment particles.

[0013] Preferably, in step S3, a harmony search algorithm is used to carry out nonlinear optimization inversion of particle concentration, and the specific method is as follows: N1, generate candidate solution vector Φ=(Φ 1, Φ 2,…, Φ D) for particle concentration; N2, for each component Φ of the solution vector Φ j , with probability P AR Make adjustments to obtain a new candidate solution Φ'; N3, recalculate the target error using the new candidate solution Φ'; N4. If the current target error is less than the target error of the last selected candidate solution, the last candidate solution is replaced with the current candidate solution; Through continuous iteration, the particle concentration Φ that minimizes the target error is found.

[0014] Preferably, when the particle size of sediment particles is measured by multi-band extinction imaging, the following formula is used for calculation: ; Where D is the particle diameter, f k (λ) is the spectral response function, I λ is the spectral intensity, and E(λ, D, m) is the extinction coefficient of the particle group.

[0015] As a preferred method, the specific method of the Levenberg–Marquardt data inversion algorithm is as follows: P1: given initial particle size D0; P2: Calculate the objective function value ; P3: Calculate the Jacobian matrix. For each frequency, calculate ; P4: Solve the normal equation: and calculate the updated amount of particle size ; P5: Update parameters: ; P6: When G ( D k ) is less than the set threshold, the iteration is stopped and the parameter vector D obtained in the final inversion is output.

[0016] Preferably, in the process of detecting the particle size of particles in the ore slurry, when the particles are adhered and the image segmentation is difficult, the RGB color space is converted to the Lab color space, and the K-means clustering algorithm is used to segment the particle image to obtain the particle size information of the particles after adhesion.

[0017] The objective of the present invention is achieved through the following technical scheme: the present invention adopts a plurality of measurement methods combining ultrasonic wave, light scattering and imaging method to jointly measure the particle concentration and particle size information of the coexisting three-phase medium of nodule particles, sediment particles and seawater, has high detection accuracy, can simultaneously detect the particle concentration (particle volume fraction) and particle size information in the ore slurry, has high detection result accuracy and fast detection speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the deep-sea mining slurry concentration and particle size measurement device.

[0019] In the figure: 1. Main pipeline, 2. Array ultrasonic sensor, 3. Branch pipeline, 4. Temperature sensor, 5. Optical detection unit, 6. Dilution pipeline, 7. Water supply pump. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0021] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0022] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0023] like Figure 1 As shown, a deep-sea mining slurry concentration and particle size measuring device includes a main pipeline 1 and an optical detection unit 5. A branch pipeline 3 is arranged on the main pipeline 1. The optical detection unit 5 includes a light source and an image acquisition module arranged corresponding to the light source. The light source and the image acquisition module are respectively located on both sides of the branch pipeline 3; an array ultrasonic sensor 2 is also arranged on the main pipeline 1; the image acquisition module and the array ultrasonic sensor 2 are both connected to the control system.

[0024] Both ends of the branch pipe 3 are connected to the main pipe 1. When the slurry flows in the main pipe 1, part of the slurry will enter from one end of the branch pipe 3, and after passing through the branch pipe 3, flow back to the main pipe from the other end of the branch pipe 3. The branch pipe 3 is arranged downstream of the array ultrasonic sensor 2.

[0025] The array ultrasonic sensor 2 includes a number of multi-band ultrasonic transducers, which are arranged along the circumferential direction of the main pipeline. To overcome the influence of flow noise, the array ultrasonic sensor 2 uses pulse coding (such as linear frequency modulation LFM signal) to increase the gain, and obtains the attenuation and propagation time through decoding technology. Narrowband filtering and phase-locked amplification are performed at the receiving end of the array ultrasonic sensor 2 to extract the pure amplitude and phase of each frequency component.

[0026] A temperature sensor 4 and a pressure sensor are also provided on the main pipeline 1. The temperature sensor 4 and the pressure sensor are installed near the optical detection unit 5. The temperature sensor 4 and the pressure sensor are used to detect the temperature and pressure of the seawater, to compensate the temperature and pressure of the detection results, and to correct the sound velocity and density parameters of the seawater to ensure the accuracy of the model input.

[0027] The image acquisition module includes an image sensor and a multispectral camera.

[0028] In addition, a dilution pipeline 6 is provided on the branch pipeline 3, and the dilution pipeline 6 is used to introduce water into the branch pipeline 3 and dilute the slurry in proportion. A water supply pump 7 is provided on the dilution pipeline 6, and the water supply pump 7 is used to control the flow rate of the dilution water.

[0029] The present invention adopts a variety of measurement methods combining ultrasonic wave, light scattering and imaging method to jointly measure the concentration and particle size information of particles coexisting in three-phase medium of nodule particles, sediment particles and seawater.

[0030] The present invention also provides a method for measuring the concentration and particle size of deep-sea mining slurry. When measuring the slurry concentration, the slurry in the branch pipe is first diluted through the dilution pipe, and the concentration of sediment particles in the branch pipe is proportionally diluted to meet the single scattering condition.

[0031] A small cavity is fixedly connected to the inner wall of the branch pipe. The small cavity is filled with a reference particle liquid with a fixed concentration. Through a regular calibration procedure, its ultrasonic attenuation is continuously monitored as a reference to correct the system drift and realize calibration and self-test in long-term deep-sea operation.

[0032] When detecting the concentration of particles in the slurry, the specific method is as follows: S1: The array ultrasonic sensor emits ultrasonic pulses, which pass through the slurry in the branch pipe. The sound velocity of the ultrasonic pulse signal is obtained through the receiving end of the array ultrasonic sensor. Sound attenuation coefficient , and the experimental complex wave number is calculated k meas ( oh ) ; Experimental complex wave number k meas ( oh ) is calculated as follows: ; S2: Set the particle concentration to Φ, set the initial value of Φ, and calculate the theoretical complex wave number related to the particle concentration Φ ; The calculation formula of the theoretical complex wave number is as follows: ; in, k 0 represents the base wave number in pure seawater, is the correction term caused by the scattering and absorption effects of particles, which depends on the sound frequency ω and the particle concentration Φ.

[0033] S3: The theoretical complex wave number The experimental complex wave number k meas ( oh ) and calculate the target error related to the particle concentration Φ , the target error is calculated as follows: ; Set the target error threshold and adjust the value of Φ; when the target error When it is less than or equal to the target error threshold, the value of Φ is the measured value of the particle concentration.

[0034] In step S3, the harmony search algorithm is used to carry out nonlinear optimization inversion of particle concentration. The specific method is as follows: N1, generate candidate solution vector Φ=(Φ 1, Φ 2,…, Φ D) for particle concentration; N2, for each component Φ of the solution vector Φ j , with probability P AR Make adjustments, the adjustment formula is: ; Where r is a random number uniformly distributed in [0,1], and a new candidate solution Φ' is obtained; b w represents bandwidth, which is the adjustment amplitude when adjusting each component of the solution vector.w Controls the step size of the adjustment.

[0035] Among them, P AR Represents a probability calculation method, which generates a random number r and puts it into the adjustment formula so that Comply with P AR Probability.

[0036] N3. Use the new candidate solution Φ' to recalculate the target error. The calculation formula is as follows: ; N4. If the current target error is smaller than the target error of the last selected candidate solution, the last candidate solution is replaced by the current candidate solution; through continuous iteration, the particle concentration Φ that minimizes the target error is found.

[0037] When measuring particle size, the particles in the slurry include nodule particles and sediment particles. The particle size of nodule particles is relatively large, usually at the millimeter or centimeter level, or even larger, and the nodule particles can be identified by the image sensor and multispectral camera in the optical detection unit. The particle size of sediment particles is relatively small, usually at the micrometer level, or even smaller, and its size is equal to or smaller than the imaging resolution of the optical detection unit.

[0038] When detecting the particle size of nodule particles in the ore slurry, the multispectral camera in the optical detection unit is used to perform backlight imaging on the nodule particles in the branch pipe. The multispectral camera performs backlight imaging on the particle group in the branch pipe in the 0° direction, and obtains the projection profile of the nodule particles to analyze the particle size of the nodule particles; and the probability of random distribution of particles at the detection position is described by Poisson distribution; the calculation formula is as follows: ; In the formula, C 2 is the corrected actual particle concentration, C 1 is the particle concentration before correction, is the mean particle diameter, s is the variance.

[0039] When detecting the particle size of sediment particles in the ore slurry, the particle size of the sediment particles is smaller than the imaging resolution of the optical detection unit and cannot be distinguished by a traditional optical camera; the present invention measures the sediment particles by a multi-band extinction imaging method; wherein, when measuring the particle size of the sediment particles by the multi-band extinction imaging method, the following formula is used for calculation: ; Where D is the particle diameter, f k (λ) is the spectral response function, I λ is the spectral intensity, and E(λ, D, m) is the extinction coefficient of the particle group.

[0040] The Levenberg–Marquardt data inversion algorithm is used to represent the overall detection data as a weighted superposition of the contributions of nodule particles and sediment particles. The least squares method is then used to fit the model to obtain the particle size distribution of nodule particles and sediment particles.

[0041] Among them, the specific method of the Levenberg–Marquardt data inversion algorithm is as follows: P1: given initial particle size D0; P2: Calculate the objective function value. The calculation formula is as follows: ; P3: Calculate the Jacobian matrix. For each frequency, calculate ; P4: Solve the normal equations: ; And calculate the updated amount of particle size ; P5: Update parameters: ; P6: When G ( D k ) is less than the set threshold, the iteration is stopped and the parameter vector D obtained in the final inversion is output.

[0042] In the present invention, for nodule particles (larger in diameter), backlight imaging can highlight the outline of the particles, making them more obvious in the background. This helps to more accurately obtain the projection area and shape information of the nodule particles, thereby accurately analyzing their particle size. For sediment particles, the multi-band extinction imaging method can effectively distinguish particles of different sizes by measuring the light absorption or scattering at different wavelengths. Since sediment particles are very small, traditional imaging methods are difficult to distinguish directly, while the extinction imaging method can indirectly determine the particle size distribution by analyzing the interaction between light and particles. The present invention combines two different technical means (backlight imaging and multi-band extinction imaging), which are respectively suitable for larger nodule particles and micron-level or even smaller sediment particles. This combination broadens the detection range of particle size, enabling the system to handle a wide range of particle size distributions from millimeters to microns, meeting the complex detection in actual operations.

[0043] In the process of detecting the particle size of particles in the ore pulp, when the particles are adhered and make image segmentation difficult, the RGB color space is converted to the Lab color space, and the K-means clustering algorithm is used to segment the particle image to obtain the particle size information after adhesion. The color information in the RGB color space is easily affected by changes in lighting conditions, while the Lab color space performs better in this regard; by converting to the Lab color space, the interference caused by uneven or changing lighting can be reduced to a certain extent, and the accuracy of image segmentation can be improved. The K-means clustering algorithm performs well when processing data with a relatively concentrated color distribution. Since the Lab color space can better capture color differences, the application of K-means clustering in this color space can more effectively identify and separate particles that adhere to each other, thereby improving the accuracy of particle size analysis. For samples with complex components such as ore pulp, the color, shape and size of the particles may vary greatly; using the Lab color space combined with the K-means clustering algorithm can more flexibly respond to these changes, improve the ability to identify particles with different characteristics, and then accurately obtain the particle size information of adhered particles.

[0044] The present invention adopts a combination of ultrasonic, light scattering and imaging methods to jointly measure the particle concentration and particle size information of the coexisting three-phase medium of nodule particles, sediment particles and seawater. The detection accuracy is high, and the particle concentration (particle volume fraction) and particle size information in the ore slurry can be detected simultaneously. The detection result is highly accurate and the detection speed is fast.

[0045] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A deep-sea mining slurry concentration and particle size measuring device, characterized in that: It includes a main pipeline and an optical detection unit. The main pipeline is provided with a branch pipeline. The optical detection unit includes a light source and an image acquisition module corresponding to the light source. The light source and the image acquisition module are respectively located on both sides of the branch pipeline. An array ultrasonic sensor is also provided on the main pipeline. The image acquisition module and the array ultrasonic sensor are both connected to the control system.

2. A deep sea mining slurry concentration and particle size measuring device according to claim 1, characterized in that: The main pipeline is also provided with a temperature sensor and a pressure sensor.

3. A deep sea mining slurry concentration and particle size measuring device according to claim 1, characterized in that: The image acquisition module includes an image sensor and a multispectral camera.

4. A deep sea mining slurry concentration and particle size measuring device according to claim 1, characterized in that: A dilution pipeline is provided on the branch pipeline, and the dilution pipeline is used to introduce water into the branch pipeline and dilute the slurry in proportion.

5. A method for measuring slurry concentration and particle size in deep sea mining, characterized in that: When detecting the concentration of particles in the slurry, the specific method is as follows: S1: The array ultrasonic sensor emits ultrasonic pulses, which pass through the slurry in the branch pipe. The sound velocity of the ultrasonic pulse signal is obtained through the receiving end of the array ultrasonic sensor. Sound attenuation coefficient , and calculate the experimental complex wave number; S2: setting the particle concentration to Φ, setting the initial value of Φ, and calculating the theoretical complex wave number related to the particle concentration Φ; S3: Compare the theoretical complex wave number with the experimental complex wave number and calculate the target error related to the particle concentration Φ ; Set the target error threshold and adjust the value of Φ; when the target error When it is less than or equal to the target error threshold, the value of Φ is the measured value of the particle concentration; The particles in the slurry include nodule particles and sediment particles. When detecting the particle size of nodule particles in the slurry, the multispectral camera in the optical detection unit is used to perform backlight imaging on the nodule particles in the branch pipe, and the projection profile of the nodule particles is obtained to analyze the particle size of the nodule particles; and the probability of random distribution of particles at the detection position is described by Poisson distribution; When detecting the particle size of sediment particles in the slurry, the multi-band extinction imaging method is used for measurement. The Levenberg–Marquardt data inversion algorithm is used to represent the overall detection data as a weighted superposition of the contributions of nodule particles and sediment particles. The least squares method is then used to fit the model to obtain the particle size distribution of nodule particles and sediment particles.

6. A method for measuring slurry concentration and particle size in deep sea mining according to claim 5, characterized in that: In step S3, the harmony search algorithm is used to carry out nonlinear optimization inversion of particle concentration. The specific method is as follows: N1, generate candidate solution vector Φ=(Φ 1, Φ 2,…, Φ D) for particle concentration; N2, for each component Φ of the solution vector Φ j , with probability P AR Make adjustments to obtain a new candidate solution Φ'; N3, recalculate the target error using the new candidate solution Φ'; N4. If the current target error is less than the target error of the last selected candidate solution, the last candidate solution is replaced with the current candidate solution; Through continuous iteration, the particle concentration Φ that minimizes the target error is found.

7. A method for measuring slurry concentration and particle size in deep sea mining according to claim 5, characterized in that: When the particle size of sediment particles is measured by multi-band extinction imaging, it is calculated using the following formula: ； Where D is the particle diameter, f k (λ) is the spectral response function, I λ is the spectral intensity, and E(λ, D, m) is the extinction coefficient of the particle group.

8. A method for measuring slurry concentration and particle size in deep sea mining according to claim 5, characterized in that: The specific method of the Levenberg–Marquardt data inversion algorithm is as follows: P1: given initial particle size D0; P2: Calculate the objective function value ; P3: Calculate the Jacobian matrix. For each frequency, calculate ； P4: Solve the normal equation: and calculate the updated amount of particle size ; P5: Update parameters: ； P6: When G ( D k ) is less than the set threshold, the iteration is stopped and the parameter vector D obtained in the final inversion is output.

9. A method for measuring concentration and particle size of deep-sea mining slurry according to claim 5, characterized in that: In the process of detecting the particle size of particles in the ore slurry, when the particles are adhered and the image segmentation is difficult, the RGB color space is converted to the Lab color space, and the K-means clustering algorithm is used to segment the particle image to obtain the particle size information after adhesion.

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