Settling funnel hydraulic gradient driven water replenishing ore dissolving salt lake brine mining method and system

Abstract

The invention discloses a salt lake brine mining method and system for hydraulically gradient-driven water replenishing and ore dissolving of a sedimentation funnel, and relates to the technical field of salt lake mineral resource development, the method comprises the following steps: S1, collecting water level data of a sedimentation funnel area, calculating gradient distribution, dividing functional areas, and generating zoning parameters; s2, based on the partition parameters, a water injection well network is arranged in the gradient direction, water injection parameters are determined according to the water level difference, and a well network scheme is generated; s3, based on a well pattern scheme, injecting the proportioning solvent into an ore bed in a layered manner to form a directional seepage field, and generating solute transport data; s4, on the basis of solute transport data, enriched brine is extracted in the collection area, the concentration is monitored, and brine parameters are generated; and S5, based on the deviation between the brine parameter and the target value, calculating the regulation amount, adjusting the injection-production parameter to maintain dynamic balance, and outputting the salt lake brine with the target concentration. By regulating and controlling the hydraulic gradient, the form of the settlement funnel is stabilized, the phenomena of stratum disturbance and ground settlement are reduced, and the ecological risk is reduced.

Description

Technical Field

[0001] This invention relates to the field of salt lake mineral resource development technology, and in particular to a method and system for salt lake brine extraction using a settling funnel-driven hydraulic gradient-driven water replenishment and mineral dissolution. Background Technology

[0002] Salt lake mineral resources are an important source of strategic minerals such as lithium, potassium, and boron. In the process of salt lake brine extraction, traditional technologies mainly employ single brine extraction or solid salt dissolution methods, which are insufficient in utilizing the deep solid minerals in the confined brine layer, resulting in a large amount of mineral resources remaining underground and unable to be effectively utilized. Long-term continuous brine extraction causes the groundwater level to drop continuously, gradually forming a settling funnel centered on the brine extraction well. A significant hydraulic gradient exists within the funnel, meaning the water level gradually decreases from the edge to the center.

[0003] Existing technologies for mining in settling funnel areas suffer from the following problems: First, uneven ore dissolution efficiency. Traditional water replenishment methods lack directional driving capabilities, resulting in insufficient contact between the solvent and solid ore. The dissolution rate of low-grade potassium ore (KCl content 1.2-2.8%) is only 25-35%, and dead dissolution zones easily form at the edge of the funnel. Second, the naturally existing hydraulic gradient (0.02-0.05) within the settling funnel is not effectively utilized, and brine diffusion to the edge leads to a reduction in recovery rate of 8-12%. Third, forced water injection methods easily cause formation disturbance, with ground subsidence rates exceeding 50 mm / a in some areas. Simultaneously, freshwater replenishment causes a sharp drop in brine salinity of 15-20%, affecting subsequent processing. Although existing technologies have proposed solutions such as brine reinjection and stratified mining, none have designed a synergistic water replenishment and ore dissolution mechanism specifically for the hydraulic characteristics of the settling funnel, making it difficult to simultaneously meet the needs of improving ore dissolution efficiency and protecting the ecological environment.

[0004] Therefore, developing a mining technology that relies on natural hydraulic gradients to achieve low energy consumption and high efficiency in mineral dissolution has become an urgent need in the current field of salt lake resource development. Summary of the Invention

[0005] This invention provides a method and system for extracting mineralized salt lake brine using a settling funnel-driven hydraulic gradient method to solve the aforementioned problems in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for extracting brine from a salt lake using a settling funnel-driven hydraulic gradient approach includes:

[0008] S1: Collect water level data in the settling funnel area, calculate gradient distribution and divide functional areas, and generate partition parameters;

[0009] S2: Based on the zoning parameters, the water injection well network is laid out along the gradient direction, the water injection parameters are determined according to the water level difference, and the well network scheme is generated.

[0010] S3: Based on the well network scheme, the proportioned solvent is injected into the ore layer in layers to form a directional seepage field and generate solute transport data;

[0011] S4: Based on solute transport data, extract and monitor the concentration of enriched brine in the collection area to generate brine parameters;

[0012] S5: Calculate the control amount based on the deviation between brine parameters and target values, adjust injection and extraction parameters to maintain dynamic balance, and output brine of target concentration.

[0013] Furthermore, S1 includes:

[0014] S11: Layout monitoring wells in a grid pattern in the settlement funnel area, collect water level depth and permeability coefficient at each point, and generate a monitoring dataset;

[0015] S12: Based on the monitoring dataset, calculate the gradient values ​​between adjacent points and construct a contour map to generate the gradient field distribution;

[0016] S13: Based on the gradient field distribution, extract the gradient change rate along the radial direction, and use the radial position corresponding to the peak point of the change rate as the region boundary to generate partition parameters.

[0017] Furthermore, S2 includes:

[0018] S21: Extract the boundary and gradient vector field of the intermediate gradient region based on the partitioning parameters to generate driving region data;

[0019] S22: Based on the data of the driving zone, the water injection direction is determined along the gradient vector, and the well spacing is determined according to the product of the gradient value and the permeability coefficient, generating a set of well location coordinates;

[0020] S23: Based on the well location coordinate set and the ore layer depth data obtained from drilling, set the water injection layer and the orientation of the screen pipe opening, and use the ratio of water level difference to seepage resistance as the pressure upper limit to generate a well network scheme.

[0021] Furthermore, the water injection layers include two depth ranges: a shallow layer of 3-10m and a deep layer of 10-30m.

[0022] The well spacing is 300-400m;

[0023] The maximum pressure shall not exceed 0.3 MPa;

[0024] The angle between the water injection direction and the gradient vector is less than 15 degrees.

[0025] Furthermore, S3 includes:

[0026] S31: Prepare a shallow solvent by mixing river water and old brine in a first ratio and a deep solvent by mixing them in a second ratio, wherein the first ratio is 2:1 and the second ratio is 4:1, thereby generating a layered solvent;

[0027] S32: Based on stratified solvent, shallow solvent is injected into mineral layers at a depth of 3-10m and deep solvent is injected into mineral layers at a depth of 10-30m through downhole packers to generate stratified injection flow;

[0028] S33: Based on stratified injection flow, the injection rate is controlled to keep the seepage velocity at 0.5-1.2 m / d, and pressure and concentration distribution are collected to generate solute transport data.

[0029] Furthermore, S4 includes:

[0030] S41: Based on the velocity field in the solute transport data, calculate the location of the solute accumulation center and generate the brine collection point location;

[0031] S42: Based on the location of the brine extraction point, arrange brine extraction well groups and set the single well flow rate to 50-80m³ / h, with a well spacing of 300-500m, to generate brine extraction flow;

[0032] S43: Based on the brine flow, mineralization and potassium ion concentration are obtained through online monitoring to generate brine parameters.

[0033] Furthermore, S5 includes:

[0034] S51: When the monitored flow velocity deviates from the range of 0.5-1.2m / d, calculate the adjustment value of the edge supply amount, adjust it by 5-10m³ / h each time, and generate the supply control amount;

[0035] S52: When the water level difference deviates from the range of 5-12m, calculate the brine extraction intensity adjustment value, adjust the pump flow rate by 5-10m³ / h each time, and generate the brine extraction control quantity.

[0036] S53: When the mineralization deviates from 280-350 g / L or the potassium ion concentration deviates from 1.8-2.5 g / L, calculate the amount of mother liquor to be replenished, where the mineralization of the mother liquor is 400-450 g / L and the concentration of the generated product is adjusted accordingly.

[0037] S54: Combine the regulation of replenishment, brine extraction, and concentration to maintain an injection-production ratio of 1.1-1.3 and continuously output brine of the target concentration.

[0038] Furthermore, it also includes:

[0039] Establish a cloud-based monitoring platform to collect water level, flow rate, and concentration data every 15 minutes.

[0040] The system compares real-time data with preset thresholds and automatically generates control commands.

[0041] Closed-loop automatic control is achieved by transmitting commands wirelessly to the control devices of water injection wells and brine extraction wells.

[0042] Furthermore, a settling funnel-driven hydraulic gradient-driven water replenishment system for mining dissolved mineral salt lake brine, comprising:

[0043] The monitoring unit is deployed in a grid pattern in the settlement funnel area to collect water level and seepage data and output zoning parameters to the well network configuration unit;

[0044] The well network configuration unit is used to receive zoning parameters, determine the location and parameters of water injection wells, and output the well network scheme to the solvent injection unit.

[0045] The solvent injection unit, which includes a directional water injection well group and a layered packer, receives the well network plan, injects the proportioned solvent in layers, and outputs solute transport data to the brine production unit.

[0046] The brine extraction unit includes a brine extraction well group and a concentration monitoring device, which is used to receive solute transport data, extract brine in the collection area, and output brine parameters to the intelligent control unit.

[0047] The intelligent control unit is used to receive brine parameters, calculate the deviation from the target value, and generate control instructions, which are fed back to the solvent injection unit and the brine extraction unit to adjust the injection and extraction parameters.

[0048] The recycling unit is used to collect the old brine tailwater from the brine extraction unit and transport it to the solvent injection unit to participate in solvent preparation, forming a closed-loop system.

[0049] Compared with the prior art, the present invention has the following advantages:

[0050] This invention fully utilizes the natural hydraulic gradient of the settling funnel, allowing water replenishment to flow naturally and significantly reducing energy consumption during the injection process. Directional guidance ensures sufficient contact between the replenished water and low-grade solid minerals, effectively improving dissolution efficiency and brine quality, thus enhancing resource utilization value. By regulating the hydraulic gradient, the morphology of the settling funnel is stabilized, reducing formation disturbance and land subsidence, thereby mitigating ecological risks. This integrated approach to water replenishment, dissolution, driving processes, and brine extraction enhances resource recovery rates and the economic viability of mining, promoting the sustainable development of the salt lake mineral resource development industry. Attached Figure Description

[0051] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0052] Figure 1 This is a flowchart of a method for extracting mineral-dissolving brine from a salt lake using a settling funnel-driven hydraulic gradient in an embodiment of the present invention.

[0053] Figure 2 This is a schematic diagram of the functional zoning of the settling funnel in an embodiment of the present invention (core brine extraction zone, gradient-driven zone, and edge conservation zone).

[0054] Figure 3 This is a layout diagram of the hydraulic gradient driven water replenishment system in an embodiment of the present invention (distribution of water injection wells, brine extraction wells, and monitoring wells).

[0055] Figure 4 This is a process flow diagram of stratified ore dissolution and water replenishment control in an embodiment of the present invention. Detailed Implementation

[0056] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0057] The embodiments of the present invention provide, as follows Figure 1 As shown, a method for extracting salt lake brine using a settling funnel-driven hydraulic gradient-based recharge method for mineral dissolution includes:

[0058] S1: Collect water level data in the settling funnel area, calculate gradient distribution and divide functional areas, and generate partition parameters;

[0059] S2: Based on the zoning parameters, the water injection well network is laid out along the gradient direction, the water injection parameters are determined according to the water level difference, and the well network scheme is generated.

[0060] S3: Based on the well network scheme, the proportioned solvent is injected into the ore layer in layers to form a directional seepage field and generate solute transport data;

[0061] S4: Based on solute transport data, extract and monitor the concentration of enriched brine in the collection area to generate brine parameters;

[0062] S5: Calculate the control amount based on the deviation between brine parameters and target values, adjust injection and extraction parameters to maintain dynamic balance, and output brine of target concentration.

[0063] The following is a detailed description with reference to specific embodiments.

[0064] Example 1

[0065] This embodiment takes a salt lake in the Qaidam Basin as an example to illustrate the specific implementation process of the salt lake brine mining method driven by the hydraulic gradient of the settling funnel for water replenishment and mineral dissolution.

[0066] S1: Collect water level data in the settling funnel area, calculate gradient distribution and divide functional areas, and generate partition parameters;

[0067] S11: Monitoring wells were deployed in a grid pattern within the target salt lake settling funnel area, with a well spacing of 500m-800m. Water level depth and formation permeability data were collected at each monitoring point through the wells, with a data acquisition interval of 15 minutes. Monitoring results showed that the water level depth at the center of the funnel was 25m, and the water level depth at the edge was 13m. Simultaneously, permeability coefficients at each point were obtained through pressure testing, ranging from 10⁻² to 10⁻². 5 Between m / s, a monitoring dataset containing coordinates, water level depth, and permeability coefficient is generated.

[0068] S12: Based on the monitoring dataset, an interpolation algorithm is used to calculate the hydraulic gradient values ​​between adjacent monitoring points. The calculation formula is: Gradient = (Elevation Difference) / (Horizontal Distance). A contour map of the hydraulic gradient for the entire area is constructed using contour mapping software, generating a gradient field distribution map. The gradient field distribution map shows that the gradient value gradually increases from the edge of the funnel towards the center, with an overall hydraulic gradient of 0.042.

[0069] S13: Based on the gradient field distribution map, extract gradient values ​​from the edge to the center along the radial direction, and calculate the gradient change rate between adjacent radial positions. Identify the radial position where the gradient change rate peaks, and use this position as the boundary line of the functional area. For example... Figure 2 As shown, based on the distribution pattern of the peak points of the gradient change rate and combined with the range of formation permeability, the settling funnel is divided into three functional zones: the core brine mining zone has a radius of 2500m, with the largest hydraulic gradient and brine salinity of 280-350g / L; the gradient-driven zone has a radius of 6000m and a hydraulic gradient of 0.03-0.05; and the peripheral conservation zone has a radius of 10000m and a hydraulic gradient ≤0.02. Zoning parameters containing the radius, gradient range, and salinity range of each zone are generated. Simultaneously, combined with solid mineralization distribution monitoring data, it is determined that the KCl content in shallow ore layers (0-8m) is 1.5%-1.8%, and the KCl content in deep ore layers (8-30m) is 1.8%-2.6%.

[0070] S2: Based on the zoning parameters, the water injection well network is laid out along the gradient direction, the water injection parameters are determined according to the water level difference, and the well network scheme is generated.

[0071] S21: Extract the boundary coordinate data of the gradient-driven zone based on the partitioning parameters. The gradient-driven zone is a ring-shaped area with a radius of 6000m. Extract the gradient vectors of each point within this area from the gradient field distribution map. The gradient vectors point from the edge conservation area to the core brine extraction area. Generate driving zone data containing the boundary coordinates of the gradient-driven zone and the gradient vector field distribution.

[0072] S22: Based on the drive zone data, the layout direction of injection wells should be determined to be along the gradient vector direction, i.e., from the peripheral conservation zone to the core brine extraction zone. This is based on the hydraulic gradient value (0.03-0.05) of the gradient drive zone and the formation permeability coefficient (10⁻³ to 10⁻³). 4 The product of m / s was used to calculate the reasonable spacing between injection wells. The calculation results show that, to ensure uniform water coverage and avoid interference between wells, the well spacing was determined to be 400m. A "ring-radial" layout was adopted, with 32 directional injection wells deployed within the gradient-driven zone, generating a well location coordinate set containing the three-dimensional coordinates of the 32 well locations.

[0073] S23: Based on the well location coordinate set and combined with the ore layer depth data obtained from drilling, the injection layer of the injection well is determined. According to the distribution of solid ore layers, the shallow injection layer is set to a depth range of 3-10m, corresponding to shallow ore layers; the deep injection layer is set to a depth range of 10-30m, corresponding to deep ore layers. The injection well adopts a vertical drilling design with downhole directional screen pipes. The screen pipe opening direction is directly facing the ore-rich zone of the solid ore layer to ensure that the replenishment water directly wets the ore layer. The screen pipe opening direction is consistent with the gradient vector direction, and the included angle is controlled within 15 degrees. Based on the water level difference (12m) between the center and edge of the settling funnel and the formation seepage resistance, the upper limit of the injection wellhead pressure is determined. The calculation formula is: upper limit of pressure = water level difference × water density × gravitational acceleration / seepage resistance coefficient. The calculation results show that the upper limit of pressure is 0.28MPa, which is rounded down to no more than 0.3MPa. Generate a well network scheme that includes well location coordinates, water injection layers (3-10m, 10-30m), screen pipe opening orientation, pressure limit (≤0.3MPa), and well spacing (400m).

[0074] S3: Based on the well network scheme, the proportioned solvent is injected into the ore layer in layers to form a directional seepage field and generate solute transport data;

[0075] S31: Prepare two solvents of different concentrations according to the dissolution requirements. Mix river water (K⁺ concentration 0.052 g / L, mineralization 100-150 g / L) with the old brine after salt production at a mass ratio of 2:1 to prepare shallow solvent RJ-1, with a mineralization of approximately 120 g / L; mix them at a mass ratio of 4:1 to prepare deep solvent RJ-2, with a mineralization of approximately 105 g / L. Solvent RJ-1 has a higher Mg²⁺ concentration, suitable for promoting K⁺ ion exchange in shallow mineral layers; solvent RJ-2 has a higher proportion of river water, suitable for dissolving deep mineral layers. The river water and old brine are separately transported to preparation tanks, and the proportions are precisely controlled by a flow meter. After thorough mixing, the layered solvents are generated.

[0076] S32: Based on a stratified solvent and well pattern scheme, stratified injection operations are implemented through directional water injection wells. A packer device is installed downhole in the water injection well, dividing the wellbore into two independent injection channels: a shallow section (3-10m) and a deep section (10-30m). RJ-1 shallow solvent is injected into the shallow mineral layer at a depth of 3-10m through the shallow injection pipeline, accounting for 70% of the total injection volume; RJ-2 deep solvent is injected into the deep mineral layer at a depth of 10-30m through the deep injection pipeline, accounting for 30% of the total injection volume. Driven by wellhead pressure (0.25-0.28MPa), the solvent enters the mineral layer pores through the screen openings. Because the water injection direction is consistent with the hydraulic gradient direction (angle <15 degrees), the solvent flows directionally towards the core brine extraction area under the combined action of gravity and the gradient, generating a stratified injection flow from the peripheral conservation area towards the core brine extraction area.

[0077] S33: Based on stratified injection flow, the injection flow rate of each injection well is adjusted through a frequency conversion control system, with the single-well injection rate controlled at 40-60 m³ / h. The injection rate is dynamically adjusted by combining real-time monitoring of formation pressure and seepage velocity data. When the seepage velocity is below 0.5 m / d, the injection flow rate is increased by 5-10 m³ / h; when the seepage velocity is above 1.2 m / d, the injection flow rate is decreased by 5-10 m³ / h, keeping the seepage velocity stably within the range of 0.5-1.2 m / d. Pressure monitoring points and tracer concentration monitoring points are set up within the seepage field to collect pressure distribution and solute concentration distribution data at each monitoring point. Monitoring data show that the solvent propagation distance in the ore layer increases linearly with time. The K⁺ concentration released from the dissolution of shallow ore layers gradually increases from an initial 0.25% to 0.95-1.15%, while the K⁺ dissolution concentration in deep ore layers reaches 1.8-2.5 g / L. Generate solute transport data that includes pressure field distribution, velocity field distribution, concentration field distribution, and solute transport trajectory.

[0078] S4: Based on solute transport data, extract and monitor the concentration of enriched brine in the collection area to generate brine parameters;

[0079] S41: Based on the velocity field distribution in the solute transport data, identify the region with the highest solute accumulation velocity. The velocity field shows that, driven by the hydraulic gradient, the dissolved high-concentration brine accumulates along the gradient direction towards the core brine extraction area. Using a streamline tracing algorithm, the location of the streamline convergence center is calculated; this location is the solute accumulation center. The solute accumulation center is located in the core brine extraction area of ​​the settling funnel, with a radius less than 2500m from the funnel center. Brine extraction point location data, including the three-dimensional coordinates of the accumulation center and the accumulation intensity distribution, is generated.

[0080] S42: Based on brine extraction point location data, deploy brine extraction well groups within the core brine extraction area. For example... Figure 3As shown, the brine extraction well group adopts a ring or grid layout, with a total of 18 brine extraction wells and a well spacing of 300-500m. Each brine extraction well is equipped with a submersible pump, with a single well extraction flow rate set at 50-80 m³ / h. Based on real-time monitoring of the water level data of each well, the workload of each well is dynamically allocated through an intelligent control system to avoid drastic fluctuations in water level caused by excessive local extraction. After all brine extraction wells are started simultaneously, the collected enriched brine is lifted to the surface, generating a brine flow with a flow rate of 900-1440 m³ / h.

[0081] S43: Based on the brine flow, online monitoring devices are installed on the outlet pipe of each brine well to measure the brine's salinity, conductivity, potassium ion concentration, and lithium ion concentration in real time. The monitoring devices sample every 15 minutes, and the data is uploaded to the cloud monitoring platform in real time via a 4G / 5G module. Monitoring results show that the salinity of the extracted brine is stable in the range of 280-350 g / L, the K⁺ concentration is 1.8-2.5 g / L, and the Li⁺ concentration meets the target recovery requirements. A brine parameter dataset containing salinity, K⁺ concentration, Li⁺ concentration, conductivity, pH value, and brine flow rate is generated.

[0082] S5: Calculate the control amount based on the deviation between brine parameters and target values, adjust injection and extraction parameters to maintain dynamic balance, and output brine of target concentration.

[0083] S51: The cloud-based monitoring platform receives flow velocity monitoring data in real time and compares the measured flow velocity with the target range of 0.5-1.2 m / d. When the flow velocity at a monitoring point is lower than 0.5 m / d (lower threshold), it is determined that the water replenishment driving force in that area is insufficient, and the required increase in edge replenishment is calculated. The adjustment strategy is: each time the replenishment is increased by 5-10 m³ / h, the total replenishment of the corresponding edge conservation area infiltration replenishment channel is increased from 80 m³ / h to 85-90 m³ / h. When the flow velocity is higher than 1.2 m / d (upper threshold), it is determined that the excessive flow velocity may cause erosion of the strata, and each time the replenishment is reduced by 5-10 m³ / h. A replenishment regulation amount containing the adjustment direction (increase / decrease) and adjustment range (5-10 m³ / h) is generated.

[0084] S52: The cloud-based monitoring platform calculates the water level difference between the center and edge of the settling funnel in real time, with a target range of 5-12m. When the water level difference is below 5m, it is determined that the extraction intensity in the core brine extraction area is too high, and the extraction intensity needs to be reduced. The adjustment strategy is as follows: suspend operations on some wells (3-5 wells) out of the 18 brine extraction wells in the core brine extraction area, and reduce the pump rate of the remaining operating wells by 5-10 m³ / h, decreasing the flow rate from 60 m³ / h to 50-55 m³ / h. After the water level difference recovers to the target range of 5-12m, operations on the suspended wells are gradually resumed. When the water level difference is above 12m, it is determined that the extraction intensity is insufficient, and the pump rate of each brine extraction well is increased by 5-10 m³ / h, increasing the flow rate from 60 m³ / h to 65-70 m³ / h. A brine extraction control quantity is generated, including the adjustment target (specific well number), adjustment direction, and adjustment magnitude.

[0085] S53: The cloud-based monitoring platform receives brine parameter data in real time and compares the mineralization and K⁺ concentration with target values. The target range for mineralization is 280-350 g / L, and the target range for K⁺ concentration is 1.8-2.5 g / L. When the mineralization is below 280 g / L, the brine is considered diluted, and high-mineralization mother liquor needs to be added. Mother liquor with a mineralization of 400-450 g / L is extracted from the evaporation tank or high-concentration brine storage tank and transported through pipelines to the mixing unit at the brine extraction well outlet. Based on the current mineralization deviation and brine extraction flow rate, the required mother liquor flow rate is calculated. For example, when the brine extraction flow rate is 1000 m³ / h, and the mineralization drops from 280 g / L to 275 g / L, the required mother liquor flow rate is approximately 12-15 m³ / h based on material balance calculations. When the mineralization is above 350 g / L, the mother liquor replenishment is reduced, and the proportion of low-mineralization water replenishment is increased. When the K⁺ concentration is below 1.8 g / L, the mother liquor replenishment volume is increased simultaneously and the water-solvent ratio is optimized to increase the proportion of old brine. A concentration control scheme including mother liquor replenishment flow rate and water-solvent ratio adjustment is generated.

[0086] S54: The injection-production ratio is calculated uniformly through a cloud-based intelligent control platform, encompassing comprehensive replenishment, brine extraction, and concentration control. Injection-production ratio = total water injection / total brine extraction, with a target range of 1.1-1.3. When the injection-production ratio is below 1.1, the replenishment volume in the edge conservation zone and the water injection volume in the gradient-driven zone are increased, reducing brine extraction intensity; when the injection-production ratio is above 1.3, the water injection volume is reduced, and the brine extraction intensity is increased. The control platform transmits the calculated control commands wirelessly to the field control devices of each injection well, brine extraction well, and replenishment channel. Upon receiving the commands, the field control devices automatically adjust the frequency of the variable frequency pump, valve opening, and mother liquor replenishment pump flow rate. During continuous system operation, real-time monitoring data shows: seepage velocity stabilizes at 0.6-1.1 m / d, water level difference remains at 6-11 m, salinity fluctuation range ≤15 g / L, K⁺ concentration stabilizes at 1.9-2.4 g / L, and the injection-production ratio remains at 1.15-1.25. The extracted brine is transported through pipelines to evaporation tanks or subsequent processing equipment, continuously outputting salt lake brine with a target concentration of 280-350 g / L mineralization and 1.8-2.5 g / L K⁺ concentration.

[0087] like Figure 4 As shown, in the stratified ore dissolution and water replenishment control process, the process involves: solvent preparation via water replenishment source → water replenishment system → stratified ore dissolution via water replenishment control → brine collection → dynamic control based on dynamic monitoring → brine extraction.

[0088] During the continuous operation of brine extraction in this embodiment, a closed-loop automatic control mechanism was also established through a cloud-based monitoring platform. The cloud-based monitoring platform collects data on water level, flow velocity, salinity, and conductivity from 32 water injection well monitoring points, 18 brine extraction well monitoring points, and several groundwater level monitoring points, with a 15-minute acquisition cycle. The platform has a built-in preset threshold database containing upper and lower limits for key parameters such as flow velocity range (0.5-1.2 m / d), water level difference range (5-12 m), salinity range (280-350 g / L), and K⁺ concentration range (1.8-2.5 g / L). The real-time acquired data is automatically compared with the preset thresholds. When any parameter exceeds the threshold range, the platform automatically triggers an alarm and generates a control command. The control command includes the specific control object (well number or equipment number), control parameters (flow rate, pressure, ratio, etc.), and control amplitude. The command is transmitted via a 4G / 5G wireless network to the corresponding water injection well control cabinet, brine extraction well frequency converter, and replenishment channel regulating valve, among other field execution devices. After receiving the command, the actuator completes parameter adjustments within 2-5 minutes and feeds back the adjusted operating status to the cloud platform, forming a closed-loop automatic control system of "monitoring-comparison-command-execution-feedback". This mechanism ensures stable operation of the system under unattended conditions, with a response speed more than 80% faster than manual control.

[0089] Statistical results from 18 months of continuous operation in this embodiment show that: the dissolution rate of low-grade potassium ore (KCl content 1.5%-2.6%) reached 72%, more than double that of the traditional method (25-35%); the K⁺ leaching concentration remained stable at 1.02%-1.11%, meeting the requirements for subsequent processing; the average monthly Li⁺ recovery rate reached 91.7%, close to the theoretical upper limit; the annual brine extraction volume reached 87.6 million m³, an increase of 36.5% compared to the traditional model; the brine recovery rate reached 90%, significantly improving resource utilization. In terms of ecological protection, the ground subsidence rate was controlled at 1.8 mm / a, far lower than the 50 mm / a of the traditional mining model; the groundwater level in the marginal conservation area rose by 0.8-1.2 m, restoring the regional water-salt balance; the recycling rate of old brine tailings reached 82%, and freshwater consumption decreased by 75%. In terms of energy consumption, due to the full utilization of the natural hydraulic gradient to drive water replenishment, the wellhead pressure of the injection well is only 0.25-0.28 MPa, which is more than 75% lower than the traditional forced water injection pressure (1.0-1.2 MPa), and the energy consumption per unit of brine production is reduced by 12%. For example... Figure 3 As shown, the three-level functional zoning of the settling funnel and the hydraulic gradient-driven water replenishment system form a stable "replenishment-dissolving-driving-brine extraction" cycle channel, achieving the synergistic goal of efficient resource development and ecological environmental protection.

[0090] Example 2

[0091] This embodiment provides a salt lake brine extraction system for implementing the above method. The system includes a monitoring unit, a well network configuration unit, a solvent injection unit, a brine extraction unit, an intelligent control unit, and a recycling unit.

[0092] The structure and function of the monitoring unit are as follows:

[0093] The monitoring unit comprises several monitoring wells, water level sensors, pressure sensors, conductivity meters, flow meters, and data acquisition devices. The monitoring wells are arranged in a grid pattern within the settling funnel area, with a grid spacing of 500m-800m, covering three functional zones: the core brine extraction zone, the gradient-driven zone, and the peripheral conservation zone. Each monitoring well is equipped with a water level sensor (range 0-50m, accuracy ±5mm) and a pressure sensor (range 0-1MPa, accuracy ±0.5%) for real-time acquisition of groundwater depth and formation pressure data. Some monitoring wells are equipped with multi-parameter water quality analyzers, capable of simultaneously measuring parameters such as salinity, conductivity, K⁺ concentration, Li⁺ concentration, and pH value. Flow meters (ultrasonic Doppler flow meters, range 0.1-5m / d, accuracy ±2%) are deployed along key flow paths in the gradient-driven zone to monitor the seepage velocity of the underground brine.

[0094] All sensors are connected to a data acquisition unit, which has a built-in 4G / 5G communication module and a solar power system. The data acquisition cycle is set to 15 minutes. Raw data such as water level, pressure, flow rate, and concentration measured by the sensors are preprocessed by the data acquisition unit and then uploaded to the cloud monitoring platform in real time. The distribution of monitoring wells forms a three-dimensional monitoring network, which can comprehensively capture the hydraulic state and solute transport dynamics in the settling funnel area.

[0095] The monitoring unit converts discrete monitoring point data into a continuous gradient field distribution map using interpolation algorithms and contour plotting programs. Based on the gradient field, the radial gradient change rate is calculated, and the radial position corresponding to the peak point of the gradient change rate is identified as the functional zone boundary. Finally, zoning parameter data is generated for three regions: the core brine extraction zone (radius 2000-3000m, maximum gradient), the gradient-driven zone (radius 5000-8000m, gradient 0.03-0.05), and the peripheral conservation zone (radius 8000-12000m, gradient ≤0.02). The zoning parameter data is output to the well network configuration unit via a communication interface as the basis for subsequent well network deployment. Figure 1 As shown, the functional zoning constructed by the monitoring unit clearly defines the hydraulic characteristics and mineral dissolution potential of each area.

[0096] The structure and function of the well network configuration unit are as follows:

[0097] The well network configuration unit includes a well location design module, drilling equipment, and downhole devices. The well location design module receives zoning parameter data from the monitoring unit and extracts the boundary coordinates and gradient vector field distribution of the gradient-driven zone. The gradient vector field displays the direction and magnitude of the hydraulic gradient, with the gradient direction pointing from the peripheral conservation zone to the core brine extraction zone. Based on the gradient vector field, the well location design module determines that the layout direction of the injection wells should be consistent with the gradient direction (angle < 15 degrees) to fully utilize the natural hydraulic gradient to drive the replenishment flow.

[0098] Based on the hydraulic gradient value (0.03-0.05) and formation permeability coefficient (10⁻³ to 10⁻³) of the gradient-driven zone. 4 The well location design module calculates a reasonable well spacing (m / s). The calculation method is: well spacing = permeability coefficient × water replenishment radius coefficient / gradient value, where the water replenishment radius coefficient is determined based on field tests. Calculation results show that when the well spacing is set to 300-400m, uniform water replenishment coverage can be achieved while avoiding interference between wells. The well location design module uses an optimization algorithm to generate a "ring-radial" well network layout scheme within the gradient-driven zone, including the three-dimensional coordinates of 32 directional injection wells.

[0099] Drilling equipment is used for on-site drilling operations based on well location coordinates. During drilling, geological parameters such as formation lithology, ore layer depth, and permeability are obtained using logging instruments. Based on the ore layer depth data obtained from drilling, the injection layers for water injection wells are determined: shallow injection layers are in the depth range of 3-10m, corresponding to shallow ore layers (KCl content 1.2-1.8%); deep injection layers are in the depth range of 10-30m, corresponding to deep ore layers (KCl content 1.8-2.8%).

[0100] The downhole equipment includes a directional screen, a packer, and a pressure regulating valve. The directional screen is made of stainless steel or PVC, with an outer diameter of 100-150mm and an opening ratio of 8-12%. The screen openings are precisely oriented, facing the ore-rich zone, with an angle of less than 15 degrees to the gradient vector direction, ensuring that the injected solvent directly penetrates the ore layer rather than flowing down the wellbore. The packer is installed downhole, dividing the wellbore into two independent channels: a shallow section and a deep section, enabling stratified water injection. The pressure regulating valve is installed at the wellhead. Based on the water level difference (5-12m) in the settling funnel and the formation permeability resistance, the upper limit of the wellhead pressure is calculated and set. The calculation formula is: Upper limit of pressure = Water level difference × Water density × Gravitational acceleration / Permeability resistance coefficient. The calculation result shows an upper limit of 0.28MPa, but the actual setting is no more than 0.3MPa.

[0101] The well network configuration unit will output complete well network scheme data, including well location coordinates, water injection layers (3-10m, 10-30m), screen opening orientation, upper pressure limit (≤0.3MPa), and well spacing (300-400m), to the solvent injection unit via a data interface to guide subsequent stratified water injection operations. For example... Figure 3 As shown, the injection well group and brine production well group constructed by the well network configuration unit form a coordinated spatial layout, making full use of the hydraulic gradient to achieve efficient water replenishment.

[0102] The structure and function of the solvent injection unit are as follows:

[0103] The solvent injection unit comprises a directional injection well group, a layered packer device, a solvent preparation system, and a flow control system. The directional injection well group consists of 32 directional injection wells distributed within the gradient drive zone; well locations and parameters are provided by the well network configuration unit. Each injection well is drilled vertically, with a depth of 30-35m determined based on the ore layer depth.

[0104] The layered packer system is installed downhole in each injection well and includes a packer body, a shallow injection pipe, and a deep injection pipe. The packer body is an expandable rubber packer, installed at a depth of 8-10m downhole, dividing the wellbore into an upper shallow section (3-10m) and a lower deep section (10-30m). The shallow injection pipe connects to the shallow screen pipe at the wellhead, and the deep injection pipe passes through the packer and connects to the deep screen pipe. The two pipes are independent of each other and can inject solvents with different ratios separately.

[0105] The solvent preparation system receives well network plans from the well network configuration unit and prepares two solvents according to the ore layer depth and ore dissolution requirements. The system includes a river water storage tank, a brine storage tank, a preparation tank, a stirrer, and a flow meter. The river water storage tank stores river water or light brine with a K⁺ concentration of 0.052 g / L and a salinity of 100-150 g / L; the brine storage tank stores the tailwater from the salt production process, with a salinity of 150-200 g / L. When preparing shallow solvent RJ-1, the mass ratio of river water to brine is precisely controlled at 2:1 using the flow meter. The two are then pumped into the preparation tank for thorough mixing. The resulting RJ-1 has a salinity of approximately 120 g / L and a relatively high Mg²⁺ concentration. When preparing deep solvent RJ-2, the mass ratio of river water to brine is 4:1. The resulting RJ-2 has a salinity of approximately 105 g / L, with a higher proportion of river water. The preparation tank is equipped with online monitoring instruments to detect the mineralization and ion concentration of the solvent in real time, ensuring the accuracy of the mixing ratio.

[0106] The flow control system includes a variable frequency pump, flow regulating valves, and a pressure monitoring instrument. RJ-1 solvent is pumped via the variable frequency pump through the shallow injection pipe to a shallow screen pipe at a depth of 3-10m, while RJ-2 solvent is pumped via the deep injection pipe to a deep screen pipe at a depth of 10-30m. Flow regulating valves are installed on each injection pipe and dynamically adjust the flow rate based on real-time monitored seepage velocity data. The single-well injection rate is controlled at 40-60 m³ / h, with 70% injected into the shallow layer and 30% into the deep layer. A wellhead pressure monitoring instrument measures the wellhead pressure in real time to ensure that the pressure does not exceed the set upper limit of 0.3 MPa.

[0107] The structure and function of the brine extraction unit are as follows:

[0108] The brine extraction unit includes a brine extraction well group and a concentration monitoring device, which is used to receive solute transport data, extract brine in the collection area, and output brine parameters to the intelligent control unit.

[0109] Based on the velocity field distribution in the solute transport data, the brine extraction unit identifies the location of the solute accumulation center and arranges brine extraction well groups in the core brine extraction area. The brine extraction well groups are distributed in a ring or grid pattern, with a well spacing of 300-500m.

[0110] Each brine extraction well includes a wellbore, a pump, and a wellhead control device. The pump is a submersible pump or a long-shaft deep well pump, with a single well extraction flow rate set at 50-80 m³ / h. The wellhead control device includes a frequency converter and a flow regulating valve, used to dynamically adjust the pumping flow rate according to instructions from the intelligent control unit.

[0111] The concentration monitoring device is installed at the outlet of the brine well and includes an online conductivity sensor, a potassium ion selective electrode, and a lithium ion selective electrode. The concentration monitoring device measures parameters such as the salinity, potassium ion (K⁺) concentration, and lithium ion (Li⁺) concentration of the extracted brine in real time, generates brine parameters, and outputs them to the intelligent control unit.

[0112] The brine extraction unit extracts enriched brine from the core brine extraction area through brine extraction well groups, ensuring that the K⁺ concentration of the extracted brine is stable at 1.8-2.5 g / L and the mineralization is maintained at 280-350 g / L.

[0113] The structure and function of the intelligent control unit are as follows:

[0114] The intelligent control unit receives brine parameters, calculates the deviation from the target value, and generates control commands, which are then fed back to the solvent injection unit and the brine extraction unit to adjust the injection and extraction parameters.

[0115] The intelligent control unit includes a cloud monitoring platform, a data processing module, a deviation calculation module, and an instruction generation module.

[0116] The cloud-based monitoring platform receives real-time data uploaded by the monitoring unit, solvent injection unit, and brine extraction unit every 15 minutes, including parameters such as water level, flow rate, pressure, and concentration.

[0117] The data processing module processes and analyzes the received real-time data to identify data trends and outliers.

[0118] The deviation calculation module compares real-time data with preset target values ​​to calculate the deviation value. The preset target values ​​include: seepage velocity 0.5-1.2m / d, water level difference 5-12m, brine salinity 280-350g / L, and potassium ion concentration 1.8-2.5g / L.

[0119] The instruction generation module generates control instructions based on the deviation value:

[0120] (1) When the seepage velocity deviates from the range of 0.5-1.2 m / d, a replenishment regulation amount is generated. If the flow velocity is lower than 0.5 m / d, the replenishment amount of the edge conservation area replenishment channel is increased by 5-10 m³ / h each time; if the flow velocity is higher than 1.2 m / d, the replenishment amount is decreased by 5-10 m³ / h each time.

[0121] (2) When the water level difference deviates from the range of 5-12m, the brine extraction control volume is generated. If the water level difference is less than 5m, the brine extraction unit is instructed to reduce the brine extraction intensity and the pumping rate of a single well is reduced by 5-10m³ / h. If necessary, some brine extraction wells are suspended. If the water level difference is greater than 12m, the brine extraction intensity is instructed to increase and the pumping rate of a single well is increased by 5-10m³ / h.

[0122] (3) When the mineralization deviates from 280-350 g / L or the potassium ion concentration deviates from 1.8-2.5 g / L, a concentration control amount is generated. If the mineralization is lower than 280 g / L, the recycling unit is instructed to replenish the high-mineralization mother liquor (400-450 g / L), and the replenishment amount is 10-20% of the current water replenishment amount; if the mineralization exceeds 320 g / L, the solvent injection unit is instructed to increase the low-mineralization solvent injection amount.

[0123] The intelligent control unit transmits control commands wirelessly (4G / 5G) to the control devices (such as frequency converters and electric regulating valves) of the solvent injection unit and the brine collection unit, realizing closed-loop automatic control of "monitoring-feedback-adjustment".

[0124] The intelligent control unit also includes an injection-production ratio control module, which integrates the supply control amount, brine production control amount and concentration control amount to maintain the injection-production ratio within the range of 1.1-1.3 and maintain the stability of the settling funnel shape.

[0125] The structure and function of the recycling unit are as follows:

[0126] The recycling unit is used to collect the old brine tailwater from the brine extraction unit and transport it to the solvent injection unit to participate in solvent preparation, forming a closed-loop system.

[0127] The recycling unit includes a brine collection system, conveying pipelines, and a mixing and proportioning device.

[0128] The old brine collection system is connected to the brine output pipe of the brine extraction unit to collect the old brine tailwater produced after evaporation and crystallization. The mineralization of the old brine tailwater is 150-200 g / L.

[0129] The transport pipeline delivers the collected brine tailwater to the solvent preparation system in the solvent injection unit. The transport pipeline is made of corrosion-resistant material and equipped with flow meters and pressure gauges.

[0130] The mixing and proportioning device mixes the old brine tailwater with river water in a ratio of 2:1 or 4:1, and then re-prepare RJ-1 or RJ-2 solvent to participate in the ore dissolution process.

[0131] Through the recycling unit, the water recycling rate reaches over 75%, reducing freshwater consumption and decreasing unit brine production energy consumption by 12%.

[0132] This system achieves integrated and coordinated operation of water replenishment, ore dissolution, brine extraction, and brine production through the collaborative operation of monitoring units, well network configuration units, solvent injection units, brine extraction units, intelligent control units, and recycling units. Utilizing the hydraulic gradient naturally formed by the settling funnel, water replenishment flows towards the core brine extraction area, with injection wellhead pressure ≤0.3MPa, significantly reducing energy consumption. Through stratified ore dissolution and intelligent control, the dissolution rate of low-grade potash ore is increased to 65-75%, the brine recovery rate is increased to 85-90%, and the ground subsidence rate is controlled at ≤2mm / a, achieving a synergistic balance between efficient resource development and ecological protection.

[0133] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of this invention.

Claims

1. A method for extracting mineral-dissolving brine from salt lakes using a settling funnel-driven hydraulic gradient approach, characterized in that, include: S1: Collect water level data in the settling funnel area, calculate gradient distribution and divide functional areas, and generate partition parameters; S2: Based on the zoning parameters, the water injection well network is laid out along the gradient direction, the water injection parameters are determined according to the water level difference, and the well network scheme is generated. S3: Based on the well network scheme, the proportioned solvent is injected into the ore layer in layers to form a directional seepage field and generate solute transport data; S4: Based on solute transport data, extract and monitor the concentration of enriched brine in the collection area to generate brine parameters; S5: Calculate the control amount based on the deviation between brine parameters and target values, adjust injection and extraction parameters to maintain dynamic balance, and output brine of target concentration.

2. The method for extracting mineral-dissolving brine from salt lakes using a settling funnel-driven hydraulic gradient approach according to claim 1, characterized in that, S1 includes: S11: Layout monitoring wells in a grid pattern in the settlement funnel area, collect water level depth and permeability coefficient at each point, and generate a monitoring dataset; S12: Based on the monitoring dataset, calculate the gradient values ​​between adjacent points and construct a contour map to generate the gradient field distribution; S13: Based on the gradient field distribution, extract the gradient change rate along the radial direction, and use the radial position corresponding to the peak point of the change rate as the region boundary to generate partition parameters.

3. The method for extracting brine from a salt lake using a settling funnel-driven hydraulic gradient approach, as described in claim 1, is characterized in that, S2 include: S21: Extract the boundary and gradient vector field of the intermediate gradient region based on the partitioning parameters to generate driving region data; S22: Based on the data of the driving zone, the water injection direction is determined along the gradient vector, and the well spacing is determined according to the product of the gradient value and the permeability coefficient, generating a set of well location coordinates; S23: Based on the well location coordinate set and the ore layer depth data obtained from drilling, set the water injection layer and the orientation of the screen pipe opening, and use the ratio of water level difference to seepage resistance as the pressure upper limit to generate a well network scheme.

4. The method for extracting brine from salt lakes using a settling funnel-driven hydraulic gradient approach based on claim 3, characterized in that: The water injection layers include two depth ranges: a shallow layer of 3-10m and a deep layer of 10-30m. The well spacing is 300-400m; The maximum pressure shall not exceed 0.3 MPa; The angle between the water injection direction and the gradient vector is less than 15 degrees.

5. The method for extracting brine from a salt lake using a settling funnel-driven hydraulic gradient approach, as described in claim 1, is characterized in that, S3 include: S31: Prepare a shallow solvent by mixing river water and old brine in a first ratio and a deep solvent by mixing them in a second ratio, wherein the first ratio is 2:1 and the second ratio is 4:1, thereby generating a layered solvent; S32: Based on stratified solvent, shallow solvent is injected into mineral layers at a depth of 3-10m and deep solvent is injected into mineral layers at a depth of 10-30m through downhole packers to generate stratified injection flow; S33: Based on stratified injection flow, the injection rate is controlled to keep the seepage velocity at 0.5-1.2 m / d, and pressure and concentration distribution are collected to generate solute transport data.

6. The method for extracting mineral-dissolving brine from salt lakes using a settling funnel-driven hydraulic gradient method according to claim 1, characterized in that, S4 include: S41: Based on the velocity field in the solute transport data, calculate the location of the solute accumulation center and generate the brine collection point location; S42: Based on the location of the brine extraction point, arrange brine extraction well groups and set the single well flow rate to 50-80m³ / h, with a well spacing of 300-500m, to generate brine extraction flow; S43: Based on the brine flow, mineralization and potassium ion concentration are obtained through online monitoring to generate brine parameters.

7. The method for extracting brine from a salt lake using a settling funnel-driven hydraulic gradient approach, as described in claim 1, is characterized in that, S5 include: S51: When the monitored flow velocity deviates from the range of 0.5-1.2m / d, calculate the adjustment value of the edge supply amount, adjust it by 5-10m³ / h each time, and generate the supply control amount; S52: When the water level difference deviates from the range of 5-12m, calculate the brine extraction intensity adjustment value, adjust the pump flow rate by 5-10m³ / h each time, and generate the brine extraction control quantity. S53: When the mineralization deviates from 280-350 g / L or the potassium ion concentration deviates from 1.8-2.5 g / L, calculate the amount of mother liquor to be replenished, where the mineralization of the mother liquor is 400-450 g / L and the concentration of the generated product is adjusted accordingly. S54: Combine the replenishment regulation, brine extraction regulation, and concentration regulation to maintain an injection-production ratio of 1.1-1.3 and continuously output brine of the target concentration.

8. The method for extracting mineral-dissolving brine from salt lakes using a settling funnel-driven hydraulic gradient approach according to claim 1, characterized in that, Also includes: Establish a cloud-based monitoring platform to collect water level, flow rate, and concentration data every 15 minutes. The system compares real-time data with preset thresholds and automatically generates control commands. Closed-loop automatic control is achieved by transmitting commands wirelessly to the control devices of water injection wells and brine extraction wells.

9. A settling funnel-driven hydraulic gradient-driven water replenishment system for mining mineralized salt lake brine, implementing the method of claim 1, characterized in that, include: The monitoring unit is deployed in a grid pattern in the settlement funnel area to collect water level and seepage data and output zoning parameters to the well network configuration unit; The well network configuration unit is used to receive zoning parameters, determine the location and parameters of water injection wells, and output the well network scheme to the solvent injection unit. The solvent injection unit, which includes a directional water injection well group and a layered packer, receives the well network plan, injects the proportioned solvent in layers, and outputs solute transport data to the brine production unit. The brine extraction unit includes a brine extraction well group and a concentration monitoring device, which is used to receive solute transport data, extract brine in the collection area, and output brine parameters to the intelligent control unit. The intelligent control unit is used to receive brine parameters, calculate the deviation from the target value, and generate control instructions, which are fed back to the solvent injection unit and the brine extraction unit to adjust the injection and extraction parameters. The recycling unit is used to collect the old brine tailwater from the brine extraction unit and transport it to the solvent injection unit to participate in solvent preparation, forming a closed-loop system.

Images