A method and system for mining rare earth ores using a converted DC electric field

Abstract

The present invention provides a method and system for mining rare earth ores using a converted direct current electric field. The system comprises: at least three rows and at least one column of injection holes arranged in the mining area, with electrodes positioned within the injection holes. Each row of electrodes is connected in parallel to an intelligent power supply control system. The intelligent power supply control system automatically determines the original power supply parameters of the weathering crust-type rare earth ore mining area through inspection. It then uses the collected pH changes, current magnitude, and current variations to match parameters in a standard parameter database to adjust the electrode positions and power supply voltage. The present invention aims to improve the difficulty in determining the power supply scheme in existing methods of electric mining of rare earth ores.

Description

Technical Field

[0001] The present invention relates to the technical field of weathering crust type rare earth mining, and in particular to a method and system for mining rare earth ores by using a converted direct current electric field. Background Art

[0002] Weathering crust-type rare earth ores have a complete distribution of rare earth elements and are rich in medium and heavy rare earth elements. They are the primary source of heavy rare earth elements, providing over 90% of the world's medium and heavy rare earth elements. However, existing ammonium salt in-situ leaching processes severely pollute surface water, groundwater, and farmland, and are also prone to sudden events such as landslides. The leaching process also suffers from slow leaching, leakage, and numerous blind spots. This in-situ ammonium salt leaching process severely restricts the mining and utilization of weathering crust-type rare earth resources in my country.

[0003] CN109402417A proposes the use of electrical mining, which mainly includes inserting an anode injection pipe and a cathode collection pipe into the rare earth mine body, with the insertion position of the cathode collection pipe being lower than the insertion position of the anode injection pipe; passing direct current between the anode injection pipe and the cathode collection pipe; in order to improve the rare earth extraction rate and shorten the mining time.

[0004] However, actual mines are large in scale, requiring multiple sets of electrodes to be energized simultaneously. This presents significant challenges with electrode placement and energization schemes, making it difficult to control the position of the positive and negative electrodes, the potential gradient, and the duration of energization, severely limiting mining efficiency. During the energized mining of weathering crust-type rare earths, the crust's physical parameters, such as conductivity, porosity, and permeability, change, necessitating the timely repositioning of the positive and negative electrodes. This is not only difficult to manually reposition, but also difficult to re-determine, as well as the duration of energization. Not only is the distribution of rare earth elements uneven within the weathering crust-type rare earth ore itself, but the mining process also contributes to this, necessitating the application of varying voltages. During energized mining, the magnitude of the applied potential gradient and the timing of these changes are difficult to determine.

[0005] Application number 202311194756.X, titled "A Method and System for Mining Rare Earth Minerals Using Direct Current," proposes a rotating power supply scheme. The scheme involves arranging at least three rows and at least one column of injection holes in the mining area; placing electrodes within the injection holes, with each row of electrodes connected in parallel to a power supply control system; adding a leaching agent to the injection holes; and dividing the mining area into M equal parts (M is a positive integer). The electrodes are energized using a rotating power supply method with a cycle from 1 to M. Compared to energizing all mining areas simultaneously, this rotating power supply scheme reduces the power consumption during the mining process and lowers the construction costs of transformers and other equipment.

[0006] However, during the power-on process, the electrolysis near the electrodes continues to increase, which not only increases the electricity consumption cost, but also causes the ions in the mining area to continuously migrate, resulting in changes in the conductivity of the mining area. After the conductivity changes, the power-on parameters need to be changed to continuously and efficiently mine rare earths. Otherwise, the effective mobility of rare earths will be reduced and the mining cycle will be extended.

[0007] On the other hand, as the power continues to be supplied, the hydrolysis near the electrode will continue to increase, and the pH near the cathode will continue to rise. When the pH value reaches the rare earth precipitation threshold, it will cause rare earth precipitation, hindering the continuous migration of rare earths. Summary of the Invention

[0008] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a method and system for mining rare earth ores using a converted DC electric field, which aims to improve the problem of difficulty in determining the power supply scheme in the existing power supply mining method for rare earth ores.

[0009] The present invention adopts the following technical solutions:

[0010] A system for mining rare earth ores using a converted direct current electric field comprises: at least three rows and at least one column of injection holes arranged in a mining area, electrodes arranged in the injection holes, a pH meter and an intelligent power control system arranged near the electrodes in the mining area, the intelligent power control system being equipped with a current and voltage detector, a conductivity detector, an integrated mother power supply, a module controller, and a parameter standard database; (the integrated mother power supply provides voltage to the module, while the module controller adjusts the positive and negative poles).

[0011] Each row of electrodes is connected in parallel to an intelligent power control system. The intelligent power control system provides the distance between the initial energized anode and cathode electrodes and the potential gradient of the energized electrodes based on the mine's resistivity and parameter standard database data, and then makes corresponding adjustments based on the uploaded pH value or current changes and the current size.

[0012] Specifically, the pH meter uploads the measured information to the intelligent power control system in real time. The intelligent power control system controller calls the information in the parameter standard database to obtain the pH value near the electrode, compares the pH value near the electrode with the precipitation threshold, and controls the positive and negative electrodes to move forward.

[0013] pH value near the electrode ( i = 1 to n refers to the average value of n pH measurement results) once it is greater than the precipitation threshold ( i=La to Lu refers to lanthanide 15 elements) then the power is first stopped and the positive and negative electrodes move forward.

[0014] When the intelligent power control system detects that the current magnitude remains unchanged when the current and voltage detectors upload to the parameter standard database or when the current between the electrodes is not 10-60A, the intelligent power control system will advance the positive and negative electrodes through the module controller or change the potential gradient through the integrated mother power supply.

[0015] Note: The forward movement of positive and negative electrodes refers to the arrangement of multiple rows and columns of electrodes in the mining area, with each row of electrodes connected in parallel to the intelligent power control system. For example, the 13th row of electrodes becomes the anode after being positively charged, and the 15th row becomes the cathode after being negatively charged. The 13th and 15th rows form a power-on circuit. When the pH value near the electrodes is compared with the precipitation threshold and the electrode position needs to be adjusted, the 13th and 15th rows of electrodes are simultaneously de-energized, while the 14th row of electrodes becomes the positive electrode and the 16th row becomes the negative electrode. In this way, the energized electrodes move in the direction of the columns relative to the original 13th and 15th rows.

[0016] Since multiple rows and columns of electrodes are arranged in the mining area, there is a situation where the 1st, 4th, 6th, 7th, 9th and 11th rows are energized at the same time. When it is necessary to move forward, the original 9th row with positive power may become negatively energized, and the original 11th row with negative power may become positively energized. Therefore, in this process, the same electrode will change from being used as the positive pole of the power supply to being used as the negative pole of the power supply, or from being used as the negative pole of the power supply to being used as the positive pole of the power supply.

[0017] The detection point of the current and voltage detector is in the current loop and is installed in the integrated mother power supply.

[0018] The current and voltage detector is used to detect the potential gradient and current of the mine in real time, and upload the data to the parameter standard database. The conductivity detector is used to check whether the current and voltage detector is abnormal.

[0019] In some examples, the original data recorded in the parameter standard database of the intelligent power supply control system in the weathering crust rare earth mining area: the initial current threshold between the electrodes is 10-60A, the precipitation threshold The data that need to be converted or calculated in the parameter standard database include: pH value near the electrode (1cm-100cm) and current between electrodes.

[0020] In some instances, the spacing between the positive and negative electrodes and the potential gradient of the originally arranged electrodes are determined by the integrated circuit mother power supply and parameter standard database: before formal mining, the intelligent power control system will automatically check the mine's resistivity RΩ·m, the positive and negative electrode spacing ≥1 / R m (and greater than one unit electrode spacing, one unit electrode spacing is the distance between electrodes in each column. Depending on the on-site conditions, the spacing between electrodes in each column is different. Therefore, based on the on-site conditions, the unit electrode spacing is optional), and the potential gradient is 10R V / m.

[0021] On the other hand, a method for mining rare earth ores using a converted direct current electric field is also provided, comprising: arranging at least three rows and at least one column of injection holes in a mining area, and arranging electrodes in the injection holes, wherein each row of electrodes is connected in parallel to an intelligent power supply control system. The intelligent power supply control system automatically checks and determines the original power supply parameters (positive and negative electrode positions and potential gradient) of the weathering crust-type rare earth ore mining area, and then calls a parameter standard database for parameter matching based on the collected pH changes and / or current magnitude and current changes to adjust the electrode positions and power supply voltage.

[0022] When the pH value near the electrode is greater than the precipitation threshold, the power is stopped first, and the positive and negative electrodes move forward;

[0023] When the current tends to be stable or the current size is not between 10-60A, the positive and negative electrodes move forward or change the potential gradient.

[0024] Furthermore, the intelligent power supply control system will automatically check and determine the power supply parameters of the weathering crust rare earth mining area:

[0025] Determine the resistivity of the weathering crust rare earth mining area, then call the parameter standard database to match the appropriate power supply method (positive and negative electrode positions and potential gradient).

[0026] Before formal mining, the intelligent power supply control system will automatically check the resistivity of the mine.

[0027] Specifically: if the resistivity of the weathering crust type rare earth mineral is RΩ·m, the distance between the positive and negative electrodes is ≥1 / Rm (and greater than one unit electrode distance), and the potential gradient is ≥10R V / m.

[0028] At the same time, the spacing between the positive and negative electrodes and the potential gradient are affected by the current between the electrodes, and the current between the electrodes should be between 10-60A.

[0029] The duration of power supply to the positive and negative electrodes is affected by the pH value near the electrodes. The pH value near the electrodes affects the occurrence state of rare earth ions. The pH value at which hydrated rare earth ions begin to precipitate is obtained by the mass average precipitation value of 15 kinds of rare earth ions. pH value near the electrode Once the precipitation threshold is exceeded Then stop the power supply first, move the positive and negative electrodes forward and then power on again.

[0030] At the same time, the intelligent power supply control system will monitor the conductivity changes in the mining area in real time and adjust the power supply parameters of the electrode as the pH and conductivity change.

[0031] In one embodiment, the data recorded in the parameter standard database includes: pH, current and voltage.

[0032] In one embodiment, the number of rows of electrodes is determined according to the area of the mining region, and the spacing between each row of electrodes is 0.5-5 meters.

[0033] Optionally, the spacing between each row of electrodes is 1 meter.

[0034] In one embodiment, the number of rows of electrodes is determined according to the area of the mining region, and the spacing between the electrodes in each row is 0.5-5 meters.

[0035] Optionally, the spacing between each column of electrodes is 1 meter.

[0036] In one embodiment, the depth of the injection hole is determined according to the thickness of the weathering crust.

[0037] Optionally, the depth of the injection hole is 5-30 meters.

[0038] In one embodiment, a voltage is applied between the positive and negative electrodes so that the potential gradient in the ore body is 10-100 V / m.

[0039] Beneficial effects of the present invention:

[0040] Compared to continuous power supply using fixed positive and negative electrodes, the proposed method of switching DC electric fields shortens the mining cycle, reduces power consumption, and improves the effective mobility of rare earth elements. During the intelligent switching DC electric field power supply process, the power supply method (positive and negative electrode positions and potential gradient) can be changed in real time based on the conductivity changes of the weathering crust-type rare earth ore, resulting in a phenomenon of intelligent switching of positive and negative electrodes.

[0041] The intelligent switching of positive and negative electrodes in this invention not only allows for the real-time development of appropriate energization methods (positive and negative electrode positions and potential gradients) based on changes in pH and conductivity, enabling rapid migration of rare earth ions, but also reduces electrolysis near the electrodes, preventing soil contamination. Furthermore, during the alternating energization process, the leaching agent and the soil in the unenergized areas can fully exchange rare earth ions, thereby improving the rare earth leaching rate. Through online monitoring and automatic control of the control system, key parameters such as the energization voltage are automatically adjusted, enabling automated mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the intelligent conversion DC electric field power-on adopted in Example 1;

[0043] Figure 2 This is a comparison chart of rare earth extraction rates between Example 1 and Comparative Example 1;

[0044] Figure 3 This is a comparison chart of power consumption between Example 1 and Comparative Example 1;

[0045] Figure 4 This is a schematic diagram of the intelligent conversion DC electric field power-on adopted in Example 2;

[0046] Figure 5 This is a comparison chart of rare earth extraction rates between Example 2 and Comparative Example 2;

[0047] Figure 6 This is a comparison chart of power consumption between Example 2 and Comparative Example 2;

[0048] Figure 7 This is a working diagram of the intelligent power supply control system of the present invention.

[0049] Note: Because each electrode is fixed in the soil, the distance between electrodes is fixed. A unit electrode spacing is the minimum distance between two electrodes. The distance between electrodes can only be an integer multiple of the unit electrode spacing. DETAILED DESCRIPTION

[0050] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0051] like Figure 7 As shown, the present invention provides a method for mining rare earth ores using a converted DC electric field, comprising: arranging at least three rows and at least one column of injection holes in a mining area, and arranging electrodes within the injection holes, wherein each row of electrodes is connected in parallel to an intelligent power supply control system. The intelligent power supply control system automatically checks and determines the power supply parameters (positive and negative electrode positions and potential gradient) of the weathering crust-type rare earth ore mining area, and then calls a parameter standard database for parameter matching based on the collected pH changes and / or current magnitude and current changes to adjust the electrode positions and power supply voltage.

[0052] When the pH value near the electrode is greater than the precipitation threshold, the power is stopped first, and the positive and negative electrodes move forward;

[0053] When the current tends to be stable or the current size is not between 10-60A, the positive and negative electrodes move forward or change the potential gradient.

[0054] For example, when the resistivity of weathering crust-type rare earth ore is 1.5Ω·m, the intelligent power supply control system gives the power-on method based on the parameter standard database, with a positive and negative electrode spacing of 1.8m and a potential gradient of 50V / m; when the resistivity changes to 0.5Ω·m during the power-on process, the potential gradient in the mining area will promptly change to 20V / m.

[0055] For example, when the pH near the electrodes during the power-on process is greater than the rare earth precipitation threshold, the positive and negative electrodes move forward, and the positive and negative poles in the mining area move forward; when the current during the power-on process stabilizes to 20A, the positive and negative poles in the mining area will move forward.

[0056] At least three rows of electrodes are arranged in the mining area. For example, the electrodes can be arranged in 3 rows, 4 rows, 5 rows, 10 rows, 20 rows, 100 rows, etc. The number of rows of electrodes is determined according to the area of the mining area. The spacing between each row of electrodes is 0.5-3 meters, for example, it can be 0.5 meters, 1 meter, 2 meters or 3 meters.

[0057] At least one row of electrodes is arranged in the mining area. For example, the number of electrodes can be 1 row, 2 rows, 3 rows, 20 rows, 50 rows, 100 rows, etc. The number of rows of electrodes is determined according to the area of the mining area. The spacing between each row of electrodes is 1.8-5 meters (i.e., 1 unit pole pitch), for example, it can be 1.8 meters, 2.5 meters or 5 meters.

[0058] The method of the present invention does not restrict the positive and negative polarity of each electrode. When the intelligent power control system implements intelligent switching of the positive and negative polarities, the same electrode can switch from being the positive power supply to being the negative power supply, or vice versa. This reduces the number of separate power supplies required by the intelligent power control system. For example, the original power-on process required nine independent power supplies to control the power supply of 12, 23, 34, ... 910 rows of electrodes. However, in this intelligent power control system, due to the switchable positive and negative polarity, only five module controllers are needed to provide 10 rows of wiring.

[0059] At the same time, the intelligent power supply control system can timely change the position of the positive and negative electrodes according to actual mining needs. For example, the distance between the positive and negative electrodes can be 1.8 meters, 2 meters, 3 meters, 3.2 meters, 4 meters, or 10 meters.

[0060] In actual mining operations, due to the large scale of mines, multiple sets of electrodes need to be energized simultaneously. During traditional electrified mining, the electrodes remain energized for extended periods, which intensifies electrolysis on the electrode surface, increasing power consumption and hindering electrified rare earth mining. Furthermore, the conductivity of weathering crust-type rare earth ore mining areas changes with continued electrification. This makes it difficult to determine appropriate electrification parameters based on pH and conductivity fluctuations, reducing the effective rare earth mining rate and increasing the mining cycle. Furthermore, weathering crust rare earth ore is a complex system with uneven conductivity across its components. Conventional power supplies struggle to adjust the electrification parameters to reflect changes in pH and conductivity, and using fixed electrification parameters for rare earth mining increases electricity costs.

[0061] The position of the positive and negative electrodes directly affects the effective mobility of rare earth ions. The rare earth content of weathering crust-type rare earth ores is uneven, and the mineral composition and structure are specifically stratified, resulting in significant differences in the conductivity of different parts of the weathering crust-type rare earth ores. The potential gradient applied between the electrodes affects the electrolytic strength and rare earth migration rate of the electrode surface. As the rare earths migrate out of the weathering crust-type rare earth mining area, the rare earth migration rate decreases, requiring a higher voltage to drive rare earth migration. The duration of power applied to the positive and negative electrodes affects the precipitation of rare earth ions on the electrode surface. Continuous power application causes the pH near the electrodes to increase, causing the precipitation of rare earth ions, requiring the position of the positive and negative electrodes to be changed. The intelligent conversion DC electric field can change the position of the positive and negative electrodes, the applied potential gradient, and the duration of power applied to the positive and negative electrodes according to the pH and current of the weathering crust-type rare earth ores.

[0062] Compared to the continuous power supply of fixed positive and negative electrodes, the intelligent power control system's DC electric field conversion power supply method can change the power supply parameters (positive and negative electrode positions and potential gradient) in real time, simplifying the complex requirements of electrode layout (the anode and cathode electrode positions need to be determined based on actual surveys, but this design is no longer necessary) and the length of wires and cables (the original electrodes were fixed with the anode distributed at the top of the mountain and the cathode distributed on the mountainside. Now all can be distributed at the top of the mountain, and the length of wires and cables can be reduced). This improves the mining efficiency during the power supply process, shortens the mining cycle, reduces the power consumption required for mining, and increases the effective mobility of rare earth ions in weathering crust-type rare earth ores. At the same time, during the process of switching the positive and negative electrodes, the rare earth ions in the leaching agent and soil in the non-powered area can be fully exchanged, thereby improving the rare earth leaching rate.

[0063] Furthermore, the parameter standard database of the intelligent power supply control system in the weathering crust rare earth mining area records the following data: the current between the electrodes is a threshold of 10-60A, the precipitation threshold

[0064] The distance between the positive and negative electrodes and the potential gradient of the original electrode are determined by the intelligent power controller and the parameter adjustment database; the pH value near the electrode Once the precipitation threshold is exceeded Then stop the power first and move the positive and negative electrodes forward.

[0065] In this energization method, the energization method (positive and negative electrode positions and potential gradient) can be timely adjusted based on changes in the conductivity of weathering crust-type rare earth ore, resulting in a phenomenon of intelligent positive and negative electrode conversion. On the one hand, an appropriate energization method can be formulated in real time based on changes in pH and conductivity, allowing rare earth ions to migrate rapidly. On the other hand, electrolysis near the electrodes is weakened to prevent soil contamination. It is worth noting that the intelligent positive and negative electrode conversion in the energization method of the present invention is not the traditional electrode swap between two sets of fixed electrodes, but rather an intelligent positive and negative electrode conversion based on changes in pH and conductivity during the mining process.

[0066] The intelligent conversion of positive and negative electrodes in the energizing method of the present invention can improve the effective migration rate of rare earth ions. The migration direction of rare earth ions is always consistent between any electrodes, and there will be no reversal of current direction and reverse migration of rare earth ions.

[0067] At the same time, compared with continuous power supply of fixed positive and negative poles, not only the mining cycle is shortened, but also the rare earth mining efficiency is improved. In the embodiment of the intelligent conversion DC electric field power supply method, 3 / 4 of the power consumption is saved.

[0068] The depth of the injection hole is determined by the range of the rich ore layer, and its depth range is from the surface to above the semi-weathered layer, which can be 5 meters, 10 meters, 20 meters or 30 meters.

[0069] When a voltage is applied between the two electrodes, rare earth ions in the soil undergo directional migration under the action of the electric field. Based on experimental results, a potential gradient of 10-800 V / m in the ore body favors the flow of rare earth ions toward the cathode. The potential gradient in the ore body can be 10 V / m, 20 V / m, 30 V / m, 40 V / m, 50 V / m, 60 V / m, or 80 V / m, etc.

[0070] The present invention also provides a system for mining rare earth ores using a converted DC electric field, comprising: arranging at least three rows and at least one column of injection holes in a mining area, arranging electrodes in the injection holes, arranging a pH meter and an intelligent power control system near the electrodes in the mining area, wherein the intelligent power control system is equipped with a current and voltage detector, a conductivity detector, an integrated mother power supply, a module controller, and a parameter standard database;

[0071] Each row of electrodes is connected in parallel to an intelligent power control system. The intelligent power control system provides the distance between the initial energized anode and cathode electrodes and the potential gradient of the energized electrodes based on the mine's resistivity and parameter standard database data, and then makes corresponding adjustments based on the uploaded pH value or current changes and the current size.

[0072] Specifically, the pH meter uploads the measured information to the intelligent power control system in real time. The intelligent power control system controller calls the information in the parameter standard database to obtain the pH value near the electrode, compares the pH value near the electrode with the precipitation threshold, and controls the positive and negative electrodes to move forward.

[0073] pH value near the electrode Once the precipitation threshold is exceeded Then stop the power first and move the positive and negative electrodes forward.

[0074] When the intelligent power control system detects that the current magnitude remains unchanged or the current between the electrodes is not within the range of 10-60A as detected by the current and voltage detector uploaded to the parameter standard database, the intelligent power control system will advance the positive and negative electrodes or change the potential gradient through the integrated mother power supply.

[0075] Compared to continuously energizing fixed positive and negative electrodes, this alternating DC electric field can change their positions in real time, increasing the effective mobility of rare earths, shortening the mining cycle of weathering crust-type rare earth ores, and reducing electricity costs. Furthermore, during the alternating energization process, the rare earth ions in the leaching agent and soil in the unenergized areas can fully exchange, thereby increasing the rare earth leaching rate.

[0076] For example, when the pH near the electrode is greater than the rare earth precipitation threshold, the power control system will power off the electrode being powered on and automatically switch to the next alternating rotation state to prevent the pH from further increasing and causing rare earth precipitation.

[0077] For example, when the current in the power-on process stabilizes to 20A, the positive and negative poles in the mining area will move forward.

[0078] In the energization method of the present invention, each row of electrodes can be connected to the positive or negative pole of the power supply in a timely manner, resulting in an intelligent conversion of positive and negative poles. On the one hand, an appropriate energization plan can be formulated in real time according to changes in pH and conductivity, and rare earth ions can migrate rapidly. On the other hand, the electrolysis near the electrode is weakened to prevent soil pollution.

[0079] However, the intelligent conversion of positive and negative poles in the energization method of the present invention is not the electrode swap between two groups of fixed electrodes in the traditional sense, but the intelligent conversion of positive and negative poles is performed according to the changes in pH value and conductivity during the mining process.

[0080] The intelligent conversion of positive and negative electrodes in the power supply scheme of the present invention can improve the effective migration rate of rare earth ions. The migration direction of rare earth ions is always consistent between any electrodes, and there will be no reversal of current direction and reverse migration of rare earth ions.

[0081] At the same time, compared with continuous power supply of fixed positive and negative poles, not only the efficiency of rare earth mining is improved, but the mining cycle is shortened by 70-80% and power consumption is reduced by 50%-80%.

[0082] Example 1

[0083] This embodiment provides a method for mining rare earth ore using a DC electric field. Experiments were conducted in the Renju mining area of Meizhou City, Guangdong Province. The method for mining rare earth ore using a DC electric field includes:

[0084] (1) Arrangement of injection holes and electrodes: 176 injection holes were evenly arranged in 16 rows and 11 columns in a test area of 15 meters in length and 10 meters in width. The spacing between the injection holes was 1 meter. The depth of the injection holes was 24 meters. A 12-meter-long electrode was arranged in each injection hole. The electrode depth ranged from the bottom of the injection hole to 12 meters above the rich ore layer. A 13-meter wire was used to connect the electrodes. The electrodes in each row and 11 columns were connected in parallel to the intelligent power control system.

[0085] (2) Arrangement of intelligent power control system: 64 pH meters are evenly distributed in 176 injection holes and connected to the intelligent power control system.

[0086] (3) Injecting the leaching agent: injecting a 2.5% ammonium sulfate solution into the injection hole, and the total amount of ammonium sulfate used is 3 times the total amount of rare earth ions.

[0087] (4) Power on: Power on by intelligently transforming the DC electric field, such as Figure 1 Table 1 shows the power-on status after automatic inspection by the intelligent power control system, as well as the power-on status after changes in pH or current in the mining area. Each change in the positive and negative electrode positions is controlled by the intelligent power supply, and the potential gradient is 50 V / m.

[0088] Table 1

[0089]

[0090] (5) Liquid collection: A kilometer-long borehole is arranged at the bottom of the mining area to collect the rare earth mother liquor mined by electricity.

[0091] The power requirement for the electrified mining process was about 4kW. 1.16 tons of rare earths were collected in one month, with a rare earth recovery rate of 95% and a total power consumption of 2129kW·h.

[0092] Comparative Example 1

[0093] This comparative example provides a method for mining rare earth ores by power supply, and the experiment was conducted in the Renju mining area of Meizhou City, Guangdong Province. The difference between this method and Example 1 lies in steps (3) and (4). In this comparative example: (3) there is no intelligent monitoring system; (4) all motors are continuously powered on in a positive-negative...positive-negative manner for 1 month.

[0094] The power requirement of the comparative electrified mining process was about 8 kW. 0.42 tons of rare earths were collected in two months, with a rare earth recovery rate of 35% and a total power consumption of 10,238 kW·h.

[0095] like Figure 2 、 Figure 3 As shown in Comparative Example 1 and Example 1, the method provided by Example 1 improves rare earth recovery by 60%, reduces power consumption by 79%, reduces power requirements by 50%, and shortens the mining cycle by 82%. In Comparative Example 1, due to the continuous power supply to all areas, the long-term power supply process produces strong polarization and electrolysis. Furthermore, the positive-negative-positive electrode arrangement and power supply scheme force at least half of the rare earths to migrate back to the negative electrode against gravity, reducing the rare earth extraction rate. Furthermore, power consumption and power requirements increase.

[0096] Example 2

[0097] This embodiment provides a method for mining rare earth ores using a converted DC electric field, and experiments were conducted in the Renju mining area of Meizhou City, Guangdong Province. This method differs from Example 1 in steps (1), (2), (3) and (4). In this embodiment:

[0098] (1) Arrangement of injection holes and electrodes: 357 injection holes were evenly arranged in 21 rows and 17 columns in the test area with a length of 30 meters and a width of 24 meters. The spacing between the injection holes was 1.5 meters. The depth of the injection holes was 15 meters. An 8-meter-long electrode was arranged in each injection hole. The electrode depth ranged from the bottom of the injection hole to 8 meters above the rich ore layer. A 7-meter wire was used to connect the electrodes. The electrodes in each row and 17 columns were connected in parallel to the control system.

[0099] (2) Arrangement of intelligent monitoring system: 84 pH meters are evenly distributed in 357 injection holes, current and voltage detectors and module controllers are installed at the terminals of the power supply, and a parameter standard database is imported.

[0100] (3) Injection of leaching agent: Inject ammonium sulfate solution with a molar concentration of 0.2M into the injection hole. The total amount of ammonium sulfate used is 4 times the total amount of rare earth ions.

[0101] (4) Power on: Power on by intelligently transforming the DC electric field, such as Figure 4 Table 2 shows the power-on status after automatic inspection by the intelligent power control system, as well as the power-on status after changes in pH or current in the mining area. Each change in the positive and negative electrode positions is controlled by the intelligent power supply, and the potential gradient is 55 V / m.

[0102] Table 2

[0103]

[0104] The power requirement for the electrified mining process was about 7kW. 3.13 tons of rare earths were collected in two months, with a rare earth recovery rate of 93% and a total power consumption of 9827kW·h.

[0105] Comparative Example 2

[0106] This comparative example provides a method for mining rare earth ores by electricity, and experiments were conducted in the Renju mining area of Meizhou City, Guangdong Province. The difference between this method and Example 2 lies in step (3). In this comparative example, (3) electricity was supplied to all electrodes in a positive-negative...positive-negative manner for three months.

[0107] The power requirement of the comparative electrified mining process was about 16 kW. 1.02 tons of rare earths were collected in three months, with a rare earth recovery rate of 30% and a total power consumption of 30,489 kW·h.

[0108] like Figure 5 、 Figure 6 As shown, it can be seen from Comparative Example 2 and Example 2 that the method provided by Example 2 increases the rare earth recovery rate by 63%, reduces the power consumption by 68%, reduces the power demand by 56%, and shortens the mining cycle by 78% compared with Comparative Example 2.

[0109] From the above, it can be seen that in the method provided by the embodiment of the present invention, the use of the intelligent conversion DC electric field power supply scheme can significantly improve the rare earth recovery rate, reduce power consumption and power requirements, and shorten the mining cycle.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for mining rare earth ores using a converted direct current electric field, comprising: Arrange at least three rows and one column of injection holes in the mining area, and arrange electrodes in the injection holes. Each row of electrodes is connected in parallel to an intelligent power supply control system. The intelligent power supply control system will determine the original power supply parameters of the weathering crust type rare earth ore mining area through automatic inspection, and then call the parameter standard database for parameter matching based on the collected pH change value, current size, and current change to adjust the electrode position and power supply voltage; When the pH value near the electrode is greater than the precipitation threshold, the power is stopped first, and the positive and negative electrodes move forward; When the current tends to be stable or the current magnitude is not between 10-60A, the positive and negative electrodes move forward or change the potential gradient; Push the positive and negative electrodes forward: When the positive and negative electrodes are pushed forward by one unit electrode spacing, if the initial current between the electrodes is not between 10-60A, continue to increase the electrode spacing forward or change the potential gradient; give priority to increasing the forward spacing.

2. The method according to claim 1, characterized in that The original power-on parameters specifically include the positions of the positive and negative electrodes and the potential gradient.

3. The method according to claim 1, characterized in that The pH value changes collected are measured by a pH meter installed near the electrode. Calculated, i = 1 to n refers to the average value of n pH measurement results, and the precipitation threshold is given by Calculation shows that i=La to Lu refer to lanthanide 15 elements.

4. The method according to claim 2, characterized in that The original power-on parameters are determined as follows: if the initial resistivity of the weathering crust-type rare earth ore is RΩ·m, the distance between the positive and negative electrodes is ≥1 / R m and is greater than one unit electrode distance, and the potential gradient is ≥10R V / m.

5. The method according to claim 4, characterized in that The potential gradient must also meet 10-100 V / m.

6. The method according to claim 1, characterized in that The number of rows of electrodes is determined by the area of the mining area, and the spacing between each row of electrodes is 0.5-5 meters.

7. The method according to claim 1, characterized in that The number of rows of electrodes is determined by the area of the mining area, and the spacing between each row of electrodes is 0.5-5 meters.

8. The method according to claim 1, characterized in that The depth of the injection hole is determined by the thickness of the weathering crust type rare earth ore; at the same time, the depth of the injection hole is 5-30 meters.

9. A system for mining rare earth ores using a converted DC electric field, characterized in that: include: Arrange at least three rows and one column of injection holes in the mining area, and place electrodes in the injection holes. Place a pH meter and an intelligent power control system near the electrodes in the mining area. The intelligent power control system is equipped with a current and voltage detector, a conductivity detector, an integrated mother power supply, a module controller, and a parameter standard database. Each row of electrodes is connected in parallel to an intelligent power control system. The intelligent power control system provides the distance between the initial energized anode and cathode electrodes and the potential gradient of the energized electrodes based on the mine's resistivity and parameter standard database data. It then makes corresponding adjustments based on the uploaded pH value or current changes and the current size. The pH meter uploads the measured information to the intelligent power control system in real time. The intelligent power control system controller calls the information in the parameter standard database to obtain the pH value near the electrode, and compares the pH value near the electrode with the precipitation threshold. Once the pH value near the electrode is greater than the precipitation threshold, the power is first stopped and the positive and negative electrodes move forward. When the intelligent power control system detects that the current magnitude remains unchanged when the current and voltage detectors upload to the parameter standard database or when the current between the electrodes is not between 10-60A, the intelligent power control system will move the positive and negative poles of the electrodes forward or change the potential gradient through the integrated mother power supply.

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