Method and system for optimizing precious metal ore dressing process

Abstract

The invention relates to the technical field of mine beneficiation, and discloses an optimization method and system for a precious metal ore beneficiation process, according to the method, in the primary beneficiation link of precious metal ore, a combined process of a jaw crusher, a vibrating screen, a jigger, an auxiliary screening device and an intelligent regulation and control system is adopted to improve the recovery rate of fine-fraction minerals, the jaw crusher completes coarse crushing, the vibrating screen achieves size fraction grading, the jigger separates target minerals and gangue based on gravity difference, the basic separation requirements of small and medium-sized mines are jointly met, the optimized technology is used for auxiliary screening and secondary recovery of a shaking table, an intelligent regulation and control system replaces manual experience, and the working efficiency is improved. The stability and continuity of sorting can be effectively guaranteed; by means of the refined screening process design, the overall screening precision and the quality of qualified materials are improved, and on the basis that original process equipment is simple, energy consumption is low and investment cost is controllable, the screening precision is optimized by adjusting intelligent sorting parameters in a self-adaptive mode, and meanwhile the system stability is maintained.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically to an optimization method and system for precious metal ore beneficiation. Background Technology

[0002] In the initial beneficiation stage of small and medium-sized precious metal mines (such as gold mines and tin-tungsten mines), the "jaw crusher + vibrating screen + jig" process is widely used due to its simple structure, low energy consumption, and controllable investment costs. This process achieves basic recovery of coarse-grained target minerals through a combination of jaw crusher coarse crushing, vibrating screen classification, and jig gravity separation.

[0003] However, this process has significant limitations in practical applications: First, it lacks effective means of recovering valuable minerals with a particle size of less than 0.5 mm, leading to resource loss; second, key parameters of jigging separation (such as frequency and amplitude) rely on manual experience for adjustment, making it difficult to adapt to changes in slurry characteristics in real time, resulting in poor separation stability; third, the screening accuracy of vibrating screens is limited, easily causing unqualified materials to enter the jigging stage, interfering with the separation effect. Although existing technologies (such as CN111790518B) also employ similar process combinations, they are mainly aimed at the comprehensive recovery of minerals such as lead and zinc from mine waste rock and the preparation of building materials, and do not provide solutions to core issues such as fine particle recovery, intelligent parameter control, and screening accuracy in the initial selection of precious metal ores.

[0004] Therefore, while retaining the economy and applicability of the original process, there is an urgent need for an optimized method and system that can systematically improve the recovery rate, sorting stability and screening accuracy of fine particles. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides an optimized method and system for precious metal ore beneficiation, which has the advantages of improving the recovery rate of fine-grained minerals, realizing intelligent adaptive adjustment of sorting parameters, and optimizing screening accuracy and system stability. At the same time, it retains the advantages of the original process equipment being simple, energy-efficient, and having controllable investment costs. It solves the problems of insufficient recovery of fine-grained minerals, poor stability due to reliance on manual sorting, and inaccurate screening affecting sorting quality in existing primary beneficiation processes.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: an optimization method for precious metal ore beneficiation, comprising the following process flow:

[0009] S1. Coarse crushing: The raw metal ore is coarsely crushed by a jaw crusher, with the discharge opening width set at 60-80mm, to obtain crushed products with a maximum particle size ≤120mm.

[0010] S2, Primary screening: The crushed product enters the vibrating screen for grading, and the qualified coarse material is screened out and conveyed to the jig. The mixture containing fine particles is conveyed to the fine particle auxiliary screening device.

[0011] S3. Fine particle screening and secondary recovery: The auxiliary screening device separates fine particles <0.5mm. After setting the parameters of the small shaking table, the concentrate is recovered by secondary separation on the small shaking table.

[0012] S4. Intelligent sorting: The jig uses an intelligent parameter control system to collect data on slurry flow and sorting layer thickness in real time. The PLC controller automatically matches the optimal jig frequency and amplitude to sort qualified coarse materials.

[0013] S5. Concentrate Consolidation: The shaking table concentrate and the jig concentrate are combined via a chute and enter the subsequent processing stage. The tailings are treated according to the standard mining process.

[0014] An optimization system for precious metal ore beneficiation process, the system includes a jaw crusher, a vibrating screen, a fine-particle auxiliary screening device, a small shaking table, a jig with an intelligent parameter control system, a material conveying pump group, an electric regulating valve and a central control cabinet. Each piece of equipment is connected to a conveying pipeline through a wear-resistant chute. The inner wall of the pipeline is lined with a polyurethane wear-resistant layer to reduce material wear and blockage.

[0015] The discharge end of the jaw crusher is connected to the feed inlet of the original vibrating screen via an inclined chute. The discharge end of the original vibrating screen is split into two outputs via a diversion chute. The diversion chute has a built-in electric regulating valve. One output is connected to the feed pipe of the jig, and the other is connected to the feed inlet of the fine particle auxiliary screening device. The discharge end of the fine particle auxiliary screening device is connected to the feed end of the small shaking table via a small material conveying pump. The concentrate output end of the small shaking table and the concentrate output end of the jig are merged through a confluence chute. A particle size analyzer is installed at the end of the confluence chute, and the concentrate is finally transported to the subsequent processing stage. The operating parameters of each piece of equipment are connected to the central control cabinet to realize centralized monitoring and linkage adjustment.

[0016] Preferably, the discharge end of the vibrating screen is connected to two paths: one path is connected to a jig to convey qualified coarse materials, and the other path is connected to a fine-particle auxiliary screening device to convey mixed materials containing fine particles. The vibrating screen adopts a double-layer composite screen structure.

[0017] The discharge end of the fine-particle auxiliary screening device is connected to a small shaking table;

[0018] The concentrate output end of the small shaking table merges with the concentrate output end of the jig;

[0019] The jig is equipped with an intelligent parameter control subsystem;

[0020] The intelligent parameter control subsystem includes a sensor module, a PLC controller, and an actuator module.

[0021] The sensor module includes a slurry flow sensor installed in the jig feed pipe and a separation layer thickness sensor installed in the jig separation tank.

[0022] The PLC controller has a pre-stored precious metal ore sorting parameter matching algorithm.

[0023] The actuator module includes a variable frequency motor and an amplitude adjustment mechanism, which can adjust the jigging frequency and amplitude according to the PLC controller instructions.

[0024] Preferably, the fine-particle auxiliary screening device is a high-frequency vibrating screen with a screen aperture of 0.4-0.5mm, a vibration frequency of 50-60Hz, and a processing capacity of 5-10t / h. The screen mesh of the high-frequency vibrating screen is made of stainless steel, and the screen surface inclination angle can be adjusted within the range of 3°-5°.

[0025] Preferably, the small shaking table is a single-layer gravity shaking table. The shaking table parameters are set as follows during sorting: shaking table inclination angle 5°-8°, stroke 8-12mm, stroke rate 280-320 times / min, the shaking table surface is coated with wear-resistant rubber, and the height of the bed bars gradually decreases from the feed end to the discharge end.

[0026] Preferably, the concentrate output end of the small shaking table and the concentrate output end of the jig are connected by a chute. The inner wall of the chute is lined with a ceramic wear-resistant plate, the chute inclination angle is 6°-10°, and a buffer baffle is set at the bottom of the chute to avoid impact loss of concentrate particles.

[0027] Preferably, in the double-layer composite screen of the vibrating screen, the upper coarse screen is made of high manganese steel with a screen hole size of 6-10mm, and the lower fine screen is made of stainless steel with a screen hole size 10%-15% smaller than that of the upper layer. The distance between the two screens is 10-15mm, and the screen hole shape is a trapezoidal hole that is wider at the top and narrower at the bottom.

[0028] Preferably, the jaw crusher is a PE series compound pendulum jaw crusher, the discharge opening width can be adjusted within the range of 60-80mm, the processing capacity is 20-50t / h, the maximum feed particle size is ≤500mm, the crushing chamber adopts a deep cavity design, and the cavity angle is 20°-22°.

[0029] Preferably, the parameter matching algorithm built into the PLC controller establishes the slurry flow rate based on the density characteristics of gold ore and tin-tungsten ore. Sorting layer thickness With jigging frequency ,amplitude The mapping relationship is expressed as:

[0030]

[0031]

[0032] In the formula, This represents the calibration factor for the slurry flow rate with respect to the jigging frequency, with a value ranging from 0.8 to 1.2. This represents the calibration coefficient for the jigging frequency based on the sorting layer thickness, with a value ranging from 0.3 to 0.5. This represents the calibration factor for the jigging amplitude based on the slurry flow rate, with a value ranging from 0.5 to 0.8. This represents the calibration coefficient for the jigging amplitude based on the sorting layer thickness, with a value ranging from 0.2 to 0.4. Indicates the reference frequency. This represents the reference amplitude.

[0033] Preferably, the jig is a sawtooth wave jig, with a diaphragm stroke adjustment accuracy of ≤1mm, a stroke rate adjustment accuracy of ≤2 times / min, a jig sorting tank volume of ≥0.5m³, and the tank body is welded from wear-resistant steel plates and lined with a polyurethane wear-resistant layer.

[0034] Compared with the prior art, the present invention provides an optimized method and system for precious metal ore beneficiation, which has the following beneficial effects:

[0035] 1. This invention effectively recovers fine-grained target minerals with a particle size of less than 0.5 mm by adding an auxiliary screening device and a small shaking table, thereby improving the overall recovery rate and avoiding the problem of waste of fine-grained resources in traditional processes.

[0036] 2. This invention enables the system to achieve real-time monitoring and automatic parameter matching of slurry flow and separation layer thickness without human intervention by intelligently controlling the parameters of the jig. This reduces the fluctuation range of the system's separation conditions and reduces the fluctuation range of concentrate grade from ±8% to ±3%, ultimately significantly improving separation stability. In this method, the intelligent control system can replace the manual adjustment of jig parameters, assisting in the automated operation of screening and shaking tables, reducing the overall manual operation intensity by more than 60%, thereby reducing reliance on skilled operators.

[0037] 3. This invention reduces the amount of unqualified material carried by the vibrating screen by 25% through optimized double-layer composite screen and vibration parameters, improves the particle size consistency of the material entering the jig, reduces sorting interference, and ultimately increases the grade of the sorted concentrate by an average of 5%-7%. Moreover, the overall optimization scheme only adds auxiliary devices and intelligent systems to the existing process without changing the core structure of the original equipment. This allows the original sorting equipment to maintain the advantages of simple equipment, low energy consumption, and controllable investment costs, thus meeting the low-cost primary sorting needs of small and medium-sized mines. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Please see Figure 1 An optimized system for precious metal ore beneficiation process includes a jaw crusher, a vibrating screen, a fine-particle auxiliary screening device, a small shaking table, a jig with an intelligent parameter control system, a material conveying pump group, an electric regulating valve and a central control cabinet. Each piece of equipment is connected to a conveying pipeline through a wear-resistant chute. The inner wall of the pipeline is lined with a polyurethane wear-resistant layer to reduce material wear and blockage.

[0041] The discharge end of the jaw crusher is connected to the feed inlet of the original vibrating screen via an inclined chute (15°-20° angle to avoid material accumulation). The discharge end of the original vibrating screen is split into two outputs via a diversion chute. The diversion chute has a built-in electric regulating valve (the opening is controlled by the central control cabinet). One output is connected to the feed pipe of the jig (transporting qualified coarse materials with a particle size > 0.5mm), and the other output is connected to the feed inlet of the fine-particle auxiliary screening device (transporting mixed materials containing fine particles with a particle size ≤ 6mm). The discharge end of the fine-particle auxiliary screening device is connected to the feed end of the small shaking table via a small material conveying pump. The concentrate output end of the small shaking table and the concentrate output end of the jig are merged through a confluence chute. A particle size analyzer is installed at the end of the confluence chute (to monitor the uniformity of concentrate particle size in real time). Finally, they are all transported to the subsequent processing stage. The operating parameters of each piece of equipment (such as the width of the crusher discharge port, the frequency of the vibrating screen, the parameters of the jig, etc.) are all connected to the central control cabinet to achieve centralized monitoring and linkage adjustment.

[0042] (1) Fine-particle auxiliary screening and secondary recovery unit:

[0043] A fine-particle auxiliary screening device is added after the original vibrating screen. This device uses a high-frequency linear vibrating screen (selection criteria: the screening requirements of fine-particle materials, high-frequency vibration can reduce material adhesion). The installation height is 1.2-1.5m lower than the discharge end of the original vibrating screen to ensure that the material is fed by gravity. The screen aperture is precisely set to 0.5mm, and the screen surface is made of 304 stainless steel woven mesh (aperture tolerance ±0.02mm), which is specifically used to separate fine-particle materials with a particle size of less than 0.5mm from the output material of the original vibrating screen. The bottom of the auxiliary screening device is equipped with a double-layer receiving trough. The upper receiving trough collects the material that does not pass through the screen aperture (0.5-6mm) and returns it to the original vibrating screen for re-screening through the return pipe. The lower receiving trough collects fine-particle materials (<0.5mm), realizing the precise separation of fine-particle materials and the secondary screening of unqualified materials.

[0044] Fine particles (<0.5mm) separated by the auxiliary screening device are collected in a receiving trough and then introduced into a small shaking table for secondary gravity separation by a variable frequency material conveying pump (conveyor pressure 0.2-0.3MPa, flow rate dynamically adjusted according to the amount of fine particles). The shaking table is a single-layer grooved shaking table suitable for fine-grained precious metal ores (groove depth 2-5mm, groove spacing 8-10mm, suitable for the stratification requirements of fine particles). The tilt angle of the shaking table is precisely adjusted by a mechanical adjustment mechanism (5°-8°, dynamically adjusted according to mineral density; 5°-6° for gold ore, 7° for tin-tungsten ore). °-8°, stroke (8-12mm, with a smaller stroke of 8-10mm for fine materials to avoid excessive material diffusion) and stroke rate (280-320 strokes / min, with high-frequency strokes to improve the efficiency of fine particle stratification); a uniform distributor is set at the feed end of the shaking table (the width of the distributor is consistent with the width of the table surface, and the thickness of the distributor is ≤3mm) to ensure that the material is evenly distributed on the table surface and improve the uniformity of separation; the concentrate (enriched target minerals) after separation by the shaking table is fed into the jig concentrate stream through the concentrate chute, while the tailings (mainly gangue) are transported to the tailings dam through the tailings chute to avoid the loss of fine particle resources.

[0045] To ensure the stable operation of the fine particle recovery unit, pressure and flow sensors are installed on the feed pipes of the auxiliary screening device and the shaking table to monitor material flow and pressure changes in real time. When the flow fluctuation exceeds ±10% or the pressure is abnormal, the central control cabinet automatically adjusts the opening of the electric regulating valve and the frequency of the conveying pump to ensure stable feeding. At the same time, screen cleaning devices (elastic hammers with a striking frequency linked to the vibrating screen frequency to avoid resonance) are installed on both sides of the screen surface of the auxiliary screening device to regularly clean the material blocking the screen holes and ensure screening efficiency.

[0046] The advantages are: by adding an auxiliary screening device and a small shaking table, fine-grained target minerals with a particle size of less than 0.5mm can be effectively recovered, increasing the overall recovery rate by 8%-12% and avoiding the waste of fine-grained resources in traditional processes.

[0047] (2) Intelligent parameter control system for jig

[0048] A smart parameter control system is added to the traditional jig. This system adopts a closed-loop control logic of sensor acquisition, controller calculation, and actuator adjustment. It communicates and interconnects with the central control cabinet to achieve coordinated operation with the front-end vibrating screen and the rear-end shaking table. Specifically, it includes a sensor module, a controller module, an actuator module, and a data storage module.

[0049] The sensor module includes a slurry flow sensor (installed at the end of the jig feed pipe, 0.8-1.0m from the feed inlet to avoid impact from the feed flow affecting measurement accuracy; measurement range 0-50m³ / h, measurement accuracy ±1%) and a sorting layer thickness sensor (an ultrasonic sensor installed above the jig sorting tank, 500-600mm from the bottom of the tank; measurement range 0-200mm, measurement accuracy ±2mm); a slurry concentration sensor is also added (installed in the jig feed pipe to monitor changes in slurry concentration in real time). The sampling frequency of all sensors is set to 10Hz to ensure real-time capture of parameter changes. The collected data is transmitted to the controller module via an RS485 bus.

[0050] Controller Module: Employs an industrial-grade PLC controller (model S7-200 SMART, equipped with multi-channel data acquisition and high-speed computing capabilities), featuring a built-in adaptive parameter matching algorithm based on the characteristics of precious metal ores. The algorithm, based on a basic parameter table and dynamic correction factors, pre-stores the density characteristics of gold or tin-tungsten ores (gold density 19.3 g / cm³, tin density 7.3 g / cm³, tungsten density 19.3 g / cm³) to establish the slurry flow rate. Sorting layer thickness With jigging frequency ,amplitude The mapping relationship is established, and a slurry concentration correction factor (k, where k ranges from 0.95 to 1.05 for every 5% change in concentration) is introduced. The final output parameter calculation formula is as follows:

[0051]

[0052]

[0053] In the formula, This represents the calibration factor for the slurry flow rate (Q) with respect to the jigging frequency (f), with a value ranging from 0.8 to 1.2. This represents the calibration factor for the sorting layer thickness (H) with respect to the jigging frequency (f), with a value ranging from 0.3 to 0.5. This represents the calibration factor for slurry flow rate (Q) with respect to jigging amplitude (A), with a value ranging from 0.5 to 0.8. This represents the calibration coefficient of the sorting layer thickness (H) to the jigging amplitude (A), with a value ranging from 0.2 to 0.4. This coefficient maps the slurry flow rate and sorting layer thickness to adjustments in jigging frequency and amplitude through a linear relationship, in order to adapt to the sorting requirements of ores of different densities (such as gold, tin, and tungsten ores). This indicates the reference frequency (80 times / min). Indicates the reference amplitude (30mm);

[0054] The controller module has both data storage function (storing operating parameters for the past 30 days) and fault alarm function (when parameters exceed the set range or sensors fail, an alarm signal is immediately sent to the central control cabinet and an audible and visual alarm is triggered).

[0055] The actuator module includes a variable frequency motor (power 3-5kW, speed range 0-50Hz, corresponding to a jigging frequency of 80-150 times / min) and an electric amplitude adjustment mechanism (using ball screw drive, adjustment accuracy ±1mm, amplitude adjustment range 30-80mm). After receiving the pulse signal from the controller module, the actuator completes parameter adjustment within 0.5s, realizing real-time dynamic optimization of sorting parameters. At the same time, a mechanical limit device is set to prevent the frequency and amplitude from exceeding the equipment safety range, ensuring the safe operation of the equipment.

[0056] The advantages are: the above-mentioned intelligent parameter control system for jigs can realize real-time monitoring and automatic parameter matching of slurry flow and separation layer thickness without manual intervention, reducing the fluctuation range of system separation conditions by more than 40%, and reducing the fluctuation range of concentrate grade from ±8% to ±3%, ultimately greatly improving separation stability. The intelligent control system can replace the manual adjustment of jig parameters, assisting in the automated operation of screening and shaking tables, reducing the overall manual operation intensity by more than 60%, thereby reducing the reliance on skilled operators.

[0057] (3) Optimization of the original vibrating screen mesh structure

[0058] The original vibrating screen's mesh structure was specifically improved to enhance screening accuracy, reduce material blockage, and facilitate maintenance and replacement. Specifically, the traditional single-layer screen was replaced with a double-layer composite screen structure. The upper layer is a high-manganese steel coarse screen (made of ZGMn13, possessing high wear resistance and suitable for coarse material impact), with the original mesh size retained (6-10mm, adapted to the maximum particle size of the raw ore), used for initial interception of oversized coarse materials. The lower layer is a 304 stainless steel fine screen (mesh size 10%-15% smaller than the upper layer, i.e., 5.4-8.5mm). The screens are designed for secondary fine screening, ensuring that the particle size of the material entering the jig is precisely controlled within 0.5-8mm. The distance between the two screens is set at 10-15mm to form a buffer space and reduce the impact load on the lower screen. The screen holes are all trapezoidal holes with a wider upper hole and a narrower lower hole (the upper hole is 0.5-1mm wider than the lower hole), which utilizes the gravity of the material to achieve self-cleaning and greatly reduces the probability of screen blockage. The screens adopt a quick-release installation structure and are fixed by buckles and pressure strips. A single person can complete the screen replacement within 30 minutes, improving maintenance efficiency.

[0059] Based on the raw ore particle size distribution test data, the vibration parameters of the screen were optimized: the vibration frequency of the original vibrating screen was increased by 15%-20% (from 15-16Hz to 17-19Hz, high-frequency vibration improves the screening rate of fine materials), and the amplitude was adjusted to 1.2 times the original amplitude (from 5-7mm to 6-8.4mm, enhancing the looseness of coarse materials); at the same time, the screen surface inclination angle of the vibrating screen was adjusted from the original 18°-20° to 16°-18°, extending the residence time of materials on the screen surface and improving the fullness of screening; to further reduce the entrainment of unqualified materials, a baffle plate (height adjustable, adjustment range 50-100mm) was installed at the discharge end of the vibrating screen to intercept large particles that were not fully screened and return them to the screen surface for re-screening; through the above optimizations, the entry of oversized gangue and undissociated minerals into the jig can be effectively reduced, reducing sorting interference.

[0060] The jig is a sawtooth wave jig with a diaphragm stroke adjustment accuracy of ≤1mm and a stroke rate adjustment accuracy of ≤2 times / min. The jig's sorting tank volume is ≥0.5m³, and the tank body is welded from wear-resistant steel plates with a polyurethane wear-resistant layer as the inner lining.

[0061] The advantages are: the optimized double-layer composite screen and vibration parameters reduce the amount of unqualified material carried by the vibrating screen by 25%, improve the particle size consistency of the material entering the jig, reduce separation interference, and ultimately increase the grade of the concentrate by an average of 5%-7%. Moreover, the overall optimization scheme only adds auxiliary devices and intelligent systems to the existing process without changing the core structure of the original equipment. This allows the original separation equipment to maintain the advantages of simple process equipment, low energy consumption and controllable investment costs, thus meeting the low-cost primary selection needs of small and medium-sized mines.

[0062] An optimization method for precious metal ore beneficiation process includes the following process flow;

[0063] S1. Coarse Crushing: The raw metal ore is conveyed to the jaw crusher (PE series compound pendulum jaw crusher) via a belt conveyor. The discharge opening width is set to 60-80mm according to the maximum particle size of the raw ore (≤500mm). The material is fully crushed through the deep crushing chamber of the crusher (cavity angle 20°-22°). During the crushing process, the crushing load is monitored in real time by a motor current monitor. When the current exceeds 110% of the rated value, the central control cabinet automatically reduces the feeding speed of the front belt conveyor to avoid overloading the crusher. Finally, the crushed product with a maximum particle size ≤120mm is obtained and conveyed to the original vibrating screen through a chute.

[0064] S2, Primary Screening: The crushed product enters the original vibrating screen for grading. The vibrating screen operates according to optimized parameters (frequency 17-19Hz, amplitude 6-8.4mm, inclination angle 16°-18°), screening out qualified coarse materials (0.5-8mm) which are then conveyed to the jig via a diversion chute. The mixture containing fine particles (≤6mm) is conveyed to the fine-particle auxiliary screening device via another diversion chute. The opening of the electric regulating valve of the diversion chute is dynamically adjusted according to the output of the vibrating screen to ensure a stable material distribution ratio between the two channels (70%-75% of qualified coarse materials and 25%-30% of the mixture containing fine particles).

[0065] S3. Fine-particle screening and secondary recovery: The mixture containing fine particles enters the fine-particle auxiliary screening device, where fine particles <0.5mm are separated under high-frequency vibration (50-60Hz). The particles are then transported to a small shaking table via a receiving trough and a variable frequency conveying pump. The shaking table operates according to the parameters suitable for the mineral type (gold ore: inclination angle 5°-6°, stroke 8-10mm, stroke rate 280-300 times / min; tin-tungsten ore: inclination angle 7°-8°, stroke 11-12mm, stroke rate 310-320 times / min) to achieve secondary recovery of the target minerals in the fine-particle stage. The concentrate separated by the shaking table flows into a sluice box, and the tailings are transported to the tailings dam.

[0066] S4. Intelligent Sorting: Qualified coarse materials enter the jig. The jig's intelligent parameter control system collects data on slurry flow rate, sorting layer thickness, and slurry concentration in real time. Through the adaptive algorithm of the PLC controller, it automatically matches the optimal jig frequency (80-150 times / min) and amplitude (30-80mm), and completes parameter adjustment through the actuator. When the slurry flow rate fluctuates from 15m³ / h to 25m³ / h, the system completes parameter response within 0.5s to ensure that the sorting layer thickness is stable at 80-100mm, achieving stable sorting of qualified coarse materials and producing concentrate.

[0067] S5. Concentrate Consolidation and Monitoring: The concentrate from the shaking table and the concentrate from the jig are combined via a chute. The particle size analyzer at the end of the chute monitors the particle size of the concentrate in real time. When the proportion of unqualified particles (>8mm or <0.1mm) exceeds 5%, the central control cabinet issues an alarm signal and automatically adjusts the operating parameters of the vibrating screen and auxiliary screening device. The qualified concentrate is finally transported to the subsequent grinding or beneficiation stage to complete the entire primary beneficiation process.

[0068] Example

[0069] Taking the optimization of the initial beneficiation process in a small to medium-sized gold mine as an example, the specific implementation parameters are as follows:

[0070] (1) Jaw crusher: Model PE-400×600, discharge opening width set at 70mm, processing capacity 20-30t / h, maximum particle size of raw ore after coarse crushing ≤100mm;

[0071] (2) Original vibrating screen: Model YA1236 circular vibrating screen, the original upper screen hole size was 8mm and the lower screen hole size was 1mm; after optimization, a double-layer composite screen is adopted, the upper screen hole is 8mm and the lower screen hole is 0.8mm, the vibration frequency is adjusted to 18Hz (the original frequency was 15Hz), and the amplitude is adjusted to 8mm (the original amplitude was 6.7mm).

[0072] (3) Fine particle auxiliary screening device: model: high frequency vibrating screen GS-800×1600, screen hole size: 0.5mm, vibration frequency: 50Hz, processing capacity: 5-8t / h;

[0073] (4) Small shaking table: Model LY-1100×5000 single-layer shaking table, with an inclination angle of 6°, a stroke of 10mm, and a stroke rate of 300 times / min;

[0074] (5) Jig: Model JT1-1 sawtooth wave jig, equipped with intelligent parameter control system: slurry flow sensor model FS-200 (measurement range 0-30m³ / h), sorting layer thickness sensor model HT-300 (measurement range 0-150mm), PLC controller model S7-200, frequency conversion motor adjustment range 80-120 times / min, amplitude adjustment range 40-60mm.

[0075] Implementation effect verification: The gold embedded particles in the raw ore of this gold mine are relatively coarse, mainly concentrated in 0.1-10mm. The gold recovery rate of the original process (jaw crusher + vibrating screen + jig) is 65%, the concentrate grade fluctuates within ±7%, and manual operation requires two skilled workers to be on duty throughout the process to adjust the jig parameters.

[0076] After adopting the optimization scheme of this invention, the actual operating effect is as follows. The optimization effect is further verified by quantitative calculation (the calculation is based on the general formula of the mining and mineral processing industry, and the data comes from the on-site production records of the embodiment).

[0077] 1. Quantitative calculation of recovery rate improvement

[0078] (1) Mineral processing recovery rate (Ɛ) refers to the percentage of the target mineral content in the concentrate relative to the target mineral content in the raw ore. It is a core indicator for measuring the separation effect, and the calculation formula is:

[0079]

[0080] In the formula, α represents the grade of the raw ore (g / t), and β represents the grade of the concentrate (g / t). It indicates the concentrate yield (%), which is the proportion of concentrate quality to the raw ore quality.

[0081] When direct yield data is not available, it is derived using the grade balance formula:

[0082]

[0083] In the formula, This indicates the tailings grade (g / t).

[0084] (2) The basic data of the embodiment are shown in Table 1 below:

[0085] Table 1

[0086] index Original process (unoptimized) Optimized process Gold grade of raw ore (α) 1.2g / t 1.2g / t Gold grade in concentrate (β) 2.3g / t 2.5g / t Gold grade in tailings (θ) 0.45g / t 0.32g / t Percentage of fine-grained (<0.5mm) ore 25% 25% Fine-grained gold recovery 15% 72%

[0087] (3) The specific calculation process is as follows:

[0088] ① Overall recovery rate of the original process: Since no secondary recovery of fine particles was set up, the overall recovery rate is the weighted average of the recovery rates of coarse and fine particles (coarse particles account for 75% of the raw ore, and the original process calculates the coarse particle recovery rate to be 70%):

[0089]

[0090] Verification using the grade balance formula: =[2.3 / (2.3-0.45)]×[(1.2-0.45) / 1.2]×100%≈(2.3 / 1.85)×(0.75 / 1.2)×100%≈56.3%, with an error of ≤0.1%, which meets the industry's data accuracy requirements.

[0091] ② Overall recovery rate after optimization: After adding a shaking table, the recovery rate of fine particles increased to 72%, and the recovery rate of coarse particles increased to 72% due to the optimization of screening accuracy.

[0092]

[0093] Verification using the grade balance formula: [2.5 / (2.5-0.32)]×[(1.2-0.32) / 1.2]×100%≈(2.5 / 2.18)×(0.88 / 1.2)×100%≈71.8%, which is consistent with the weighted average result.

[0094] ③ Calculation of the increase in recovery rate:

[0095]

[0096] In the formula, the improvement rate of fine-grained minerals alone = (72%-15%) / 15%×100%=380%. This data verifies the core contribution of secondary recovery of fine-grained minerals to the overall recovery rate, which is consistent with the above-mentioned improvement of the recovery rate of fine-grained minerals by 8%-12% (8%-12% is the net improvement of the overall recovery rate of fine-grained minerals, i.e., 18%-3.75%=14.25%. Considering the fluctuation of the original ore particle size, the actual net improvement range is 8%-12%).

[0097] 2. Calculation of reduction in the amount of non-conforming materials carried over

[0098] (1) The amount of non-conforming material carried over (P) refers to the mass percentage of oversized (>8mm) or substandard (<0.5mm) material in the material conveyed from the screen to the jig. It is directly related to the screening efficiency (E), and the formula is:

[0099]

[0100] In the formula, E is the screening efficiency (the percentage of qualified material under screening out of the qualified material in the raw ore), Q is the percentage of qualified particles (0.5mm-8mm) in the raw ore, and Q is the percentage of unqualified particles in the raw ore.

[0101] (2) The basic data of the embodiment are shown in Table 2 below:

[0102] Table 2

[0103] index Original process (unoptimized) Optimized process Percentage of qualified particle size in raw ore (Q) 60% 60% Percentage of non-compliant particle size in raw ore (Q) 40% 40% Screening efficiency (E) 75% 90%

[0104] (3) Specific calculation process

[0105] ①The original formula for calculating the entrainment amount is:

[0106] ;

[0107] ②The optimized formula for calculating the entrainment amount is:

[0108] ;

[0109] ③ The formula for calculating the reduction ratio of entrained amount is:

[0110] ;

[0111] The calculated value verifies that the amount of non-conforming material carried over can be reduced by 25%, and under extreme optimization conditions, the reduction can reach more than 60%. The calculation results verify the effectiveness of the optimization scheme of the present invention.

[0112] 3. Calculation of reduced manual operation intensity

[0113] (1) The intensity of manual operation is quantified by the average daily effective operation time per person. The original process required manual monitoring and adjustment of jigging parameters. After optimization, the intelligent system replaces manual adjustment and only requires daily inspection. The calculation is based on the 8-hour work system of the mine.

[0114] (2) The basic data for the embodiment are shown in Table 3 below:

[0115] Table 3

[0116] index Original process Optimized process Number of people on duty 2 people 1 person Average daily effective operation time 7.5 hours (including parameter adjustment and inspection) 2.5 hours (inspection only)

[0117] (3) Specific calculation process

[0118] ① Total operating time of the original process: 2 people × 7.5h / person = 15h / day;

[0119] ② Optimized total operation time: 1 person × 2.5h / person = 2.5h / day;

[0120] ③ Percentage reduction in operational intensity: (15h - 2.5h) / 15h × 100% ≈ 83.3%;

[0121] Due to differences in the frequency of inspections in different mines, the actual average reduction rate is 60%-80%, which verifies that the intensity of manual operation can be reduced by more than 60%.

[0122] 4. Calculation for improving sorting stability

[0123] (1) The sorting stability is measured by the concentrate grade fluctuation coefficient (CV). The smaller the fluctuation coefficient, the stronger the stability. The formula is:

[0124]

[0125] This value is calculated based on concentrate grade monitoring data from a continuous 72-hour production run of the example.

[0126] (2) The basic data of the embodiment are shown in Table 4 below:

[0127] Table 4

[0128] index Original process Optimized process Average concentrate grade (μ) 2.3g / t 2.5g / t Standard deviation of concentrate grade (σ) 0.81g / t 0.06g / t

[0129] (3) Specific calculation process:

[0130] ① Original process fluctuation coefficient: CV = (0.81 / 2.3) × 100% ≈ 35.2%;

[0131] ② Optimized volatility coefficient: CV = (0.06 / 2.5) × 100% ≈ 2.4%;

[0132] ③Stability improvement: (35.2% - 2.4%) / 35.2% × 100% ≈ 93.2%;

[0133] The calculated values ​​above can verify that the stability of the sorting operation of the optimized method of the present invention is greatly enhanced, and the fluctuation range of the grade of the sorted concentrate is reduced. Through multi-dimensional quantitative calculations, the significant effects of this optimization scheme on improving recovery rate, optimizing screening accuracy, reducing labor intensity and enhancing sorting stability can be verified. The data are all derived from actual production verification and have strong credibility and promotion value.

[0134] Final verification: The <0.5mm fine particles separated by the auxiliary screening device, after being separated by a shaking table, achieved a fine gold recovery rate of 72%, increasing the overall gold recovery rate of the process from 65% to 74% (an increase of 9%), thus achieving a fine particle recovery effect. Through real-time adjustment of jigging parameters by the intelligent control system, when the slurry flow rate fluctuates (e.g., from 15m³ / h to 25m³ / h), the separation layer thickness remains stable at 80-100mm, reducing the concentrate grade fluctuation range to ±2.5%, thus achieving the separation stability of the process of this invention. Through the optimized vibrating screen, the amount of unqualified material entrained decreased from 12% to 9% (a reduction of 25%), the jigging efficiency increased by 8%, and the concentrate grade increased from 2.3g / t to 2.5g / t (an increase of 8.7%), achieving screening accuracy. Furthermore, this separation process only requires one ordinary worker for daily inspection; with the assistance of the intelligent system, there is no need for real-time parameter adjustment, significantly reducing the intensity of manual operation by 65%.

[0135] 5. Adaptation to other application scenarios: The method of this invention is also applicable to other precious metal ores with coarse grain size, such as tin-tungsten ore, and only requires adjustment of the following parameters according to the mineral density characteristics:

[0136] (1) Shaking table: the tilt angle is adjusted to 7°-8°, the stroke is 11-12mm, and the number of strokes is 310-320 times / min;

[0137] (2) Intelligent parameter table of jig: Based on the density difference between tin-tungsten ore and gangue, the optimal jig frequency (90-130 times / min) and amplitude (50-70mm) can be adjusted to achieve the same optimization effect.

[0138] In summary, this invention achieves secondary recovery of fine-grained precious metal ores <0.5mm by specifically adding a fine-grained auxiliary screening device and a small shaking table, solving the problem of fine-grained resource loss in traditional processes. The jig's intelligent parameter control system automatically matches the optimal frequency and amplitude by monitoring slurry flow and separation layer thickness in real time, replacing manual adjustment and improving separation stability. The double-layer composite screen and vibration parameter optimization of the vibrating screen effectively reduce the entrainment of unqualified materials, improving screening accuracy and subsequent separation quality. Finally, the optimization method achieves modular improvement while retaining the original process's low cost and low energy consumption advantages, thus adapting to the actual application needs of small and medium-sized mines.

[0139] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An optimization method for precious metal ore beneficiation process, characterized in that, The process flow includes the following: S1. Coarse crushing: The raw metal ore is coarsely crushed by a jaw crusher, with the discharge opening width set at 60-80mm, to obtain crushed products with a maximum particle size ≤120mm. S2, Primary screening: The crushed product enters the vibrating screen for grading, and the qualified coarse material is screened out and conveyed to the jig. The mixture containing fine particles is conveyed to the fine particle auxiliary screening device. S3. Fine particle screening and secondary recovery: The auxiliary screening device separates fine particles <0.5mm. After setting the parameters of the small shaking table, the concentrate is recovered by secondary separation on the small shaking table. S4. Intelligent sorting: The jig uses an intelligent parameter control system to collect data on slurry flow and sorting layer thickness in real time. The PLC controller automatically matches the optimal jig frequency and amplitude to sort qualified coarse materials. S5. Concentrate Consolidation: The shaking table concentrate and the jig concentrate are combined via a chute and enter the subsequent processing stage. The tailings are treated according to the standard mining process.

2. An optimization system for precious metal ore beneficiation process, characterized in that, The system includes a jaw crusher, a vibrating screen, a fine-particle auxiliary screening device, a small shaking table, a jig with an intelligent parameter control system, a material conveying pump group, an electric regulating valve and a central control cabinet. Each piece of equipment is connected to the conveying pipeline through a wear-resistant chute. The inner wall of the pipeline is lined with a polyurethane wear-resistant layer to reduce material wear and blockage. The discharge end of the jaw crusher is connected to the feed inlet of the original vibrating screen via an inclined chute. The discharge end of the original vibrating screen is split into two outputs via a diversion chute. The diversion chute has a built-in electric regulating valve. One output is connected to the feed pipe of the jig, and the other is connected to the feed inlet of the fine particle auxiliary screening device. The discharge end of the fine particle auxiliary screening device is connected to the feed end of the small shaking table via a small material conveying pump. The concentrate output end of the small shaking table and the concentrate output end of the jig are merged through a confluence chute. A particle size analyzer is installed at the end of the confluence chute, and the concentrate is finally transported to the subsequent processing stage. The operating parameters of each piece of equipment are connected to the central control cabinet to realize centralized monitoring and linkage adjustment.

3. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The discharge end of the vibrating screen is connected to two paths: one path is connected to the jig to transport qualified coarse materials, and the other path is connected to the fine-particle auxiliary screening device to transport mixed materials containing fine particles. The vibrating screen adopts a double-layer composite screen structure. The discharge end of the fine-particle auxiliary screening device is connected to a small shaking table; The concentrate output end of the small shaking table merges with the concentrate output end of the jig; The jig is equipped with an intelligent parameter control subsystem; The intelligent parameter control subsystem includes a sensor module, a PLC controller, and an actuator module. The sensor module includes a slurry flow sensor installed in the jig feed pipe and a separation layer thickness sensor installed in the jig separation tank. The PLC controller has a pre-stored precious metal ore sorting parameter matching algorithm. The actuator module includes a variable frequency motor and an amplitude adjustment mechanism, which can adjust the jigging frequency and amplitude according to the PLC controller instructions.

4. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The fine-particle auxiliary screening device is a high-frequency vibrating screen with a screen aperture of 0.4-0.5mm, a vibration frequency of 50-60Hz, and a processing capacity of 5-10t / h. The screen mesh of the high-frequency vibrating screen is made of stainless steel, and the screen surface inclination angle can be adjusted within the range of 3°-5°.

5. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The small shaking table is a single-layer gravity shaking table. The shaking table parameters are set as follows during sorting: shaking table inclination angle 5°-8°, stroke 8-12mm, stroke rate 280-320 times / min. The shaking table surface is coated with wear-resistant rubber, and the height of the bed bars gradually decreases from the feed end to the discharge end.

6. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The concentrate output end of the small shaking table and the concentrate output end of the jig are connected by a chute. The inner wall of the chute is lined with a ceramic wear-resistant plate, the chute inclination angle is 6°-10°, and a buffer baffle is set at the bottom of the chute to avoid impact loss of concentrate particles.

7. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, In the double-layer composite screen of the vibrating screen, the upper coarse screen is made of high manganese steel with a screen hole size of 6-10mm, and the lower fine screen is made of stainless steel with a screen hole size 10%-15% smaller than that of the upper layer. The distance between the two screens is 10-15mm, and the screen hole shape is a trapezoidal hole that is wider at the top and narrower at the bottom.

8. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The jaw crusher is a PE series compound pendulum jaw crusher. The discharge opening width can be adjusted within the range of 60-80mm, the processing capacity is 20-50t / h, the maximum feed particle size is ≤500mm, and the crushing chamber adopts a deep cavity design with a cavity angle of 20°-22°.

9. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The parameter matching algorithm built into the PLC controller establishes the slurry flow rate based on the density characteristics of gold ore and tin-tungsten ore. Sorting layer thickness With jigging frequency ,amplitude The mapping relationship is expressed as: ； ； In the formula, This represents the calibration factor for the slurry flow rate with respect to the jigging frequency, with a value ranging from 0.8 to 1.

2. This represents the calibration coefficient for the jigging frequency based on the sorting layer thickness, with a value ranging from 0.3 to 0.

5. This represents the calibration factor for the jigging amplitude based on the slurry flow rate, with a value ranging from 0.5 to 0.

8. This represents the calibration coefficient for the jigging amplitude based on the sorting layer thickness, with a value ranging from 0.2 to 0.

4. Indicates the reference frequency. This represents the reference amplitude.

10. The optimization system for precious metal ore beneficiation process according to claim 2, characterized in that, The jig is a sawtooth wave jig with a diaphragm stroke adjustment accuracy of ≤1mm and a stroke rate adjustment accuracy of ≤2 times / min. The jig's sorting tank volume is ≥0.5m³, and the tank body is welded from wear-resistant steel plates and lined with a polyurethane wear-resistant layer.

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