A process for extracting gold by dynamic circulation cascade adsorption with noble liquid and its system

Abstract

This invention relates to a dynamic circulating gradient adsorption process and system for gold extraction from precious metal solutions, comprising: separating the precious metal solution into high, medium, and low grades; targeted calcium ion inhibition and synergistic scale inhibition treatment, which involves adding a composite agent of polyaspartic acid, sodium citrate, and carboxymethyl chitosan to the different grades of precious metal solutions to form soluble and stable complexes of free calcium ions in each solution, preventing scaling; and cross-group dynamic carbon circulating gradient adsorption, in which different grades of precious metal solutions are transferred to corresponding adsorption tower groups at different flow rates for activated carbon adsorption, and gold-loaded carbon is circulated across groups during adsorption to improve adsorption efficiency and shorten the adsorption cycle. The system includes multiple heap leaching fields, each connected to a No. 1, No. 2, and No. 3 precious metal solution pipe. This invention significantly improves the gold recovery rate from precious metal solutions, optimizes adsorption efficiency, and provides an efficient, economical, and environmentally friendly solution for heap leaching gold extraction.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a dynamic circulating stepped adsorption gold extraction process and system for precious liquid fractionation. Background Technology

[0002] In heap leaching, after gold-bearing ore is leached, the precious metal solution is typically adsorbed with activated carbon to recover gold. However, existing processes have several problems, especially the significant differences in the grade of the precious metal solution in different leaching cycles. Generally, the grade is high in the early stages, gradually decreases in the middle stages, and is even lower in the later stages due to washing. Current processes concentrate the precious metal solutions from various heaps into a single pool and then use activated carbon for adsorption. This mixed and centralized adsorption method has the following drawbacks:

[0003] (1) High-grade solution is diluted: Due to the large differences in the grade of precious solution in different leaching cycles at different stockpiles, the high-grade solution will be diluted by the low-grade solution after mixing, resulting in a decrease in grade. Since the adsorption rate of activated carbon is positively correlated with the initial concentration gradient of the solution, this leads to a decrease in the adsorption efficiency of activated carbon and a longer adsorption cycle. Currently, the grade of gold-loaded carbon is about 2000-3000 g / t, and the adsorption cycle is 20-30 days.

[0004] (2) The gold recovery rate is reduced: due to the low grade of gold-loaded carbon, the gold recovery rate is reduced and the analysis cost is increased.

[0005] (3) Severe calcification problem: A certain amount of lime must be added to the stockpile, resulting in a high calcium content in the precious liquor. Direct adsorption of the precious liquor often leads to severe calcification of the activated carbon in the tower, carbon caking, and reduced carbon adsorption efficiency. In addition, the lean liquor after adsorption is continued to be used for spraying in the stockpile, which often leads to calcium buildup in the spray pipes and nozzles, reducing spraying efficiency and requiring frequent nozzle replacement.

[0006] To address the aforementioned issues, this invention proposes a dynamic circulating stepped adsorption process and system for gold extraction using a fractional flow of precious liquid. The main objective is to improve the adsorption method of the precious liquid, resolve the impact of calcium ions in the precious liquid, optimize the adsorption method of the adsorption tower on gold-loaded carbon, thereby improving adsorption efficiency and the grade of gold-loaded carbon, shortening the adsorption cycle, increasing spray efficiency, and reducing the frequency of nozzle and pipeline replacement. Summary of the Invention

[0007] This invention provides a gold extraction process and system based on dynamic circulating stepwise adsorption of precious liquids.

[0008] The specific technical solution is as follows:

[0009] A gold extraction process using a fractional flow dynamic circulation stepwise adsorption method with a noble liquid includes the following steps:

[0010] S1. Precious liquor separation and diversion: During the heap leaching process, the grade of the precious liquor in the heap is detected, and high, medium and low grade precious liquors are separated according to the grade and diverted to different mixing tanks respectively.

[0011] This step involves separating the heap leaching precious liquor into high-grade (>1.5 g / m³) liquors based on the gold ion concentration (grade) of the precious liquor. 3 Medium grade (0.5~1.5g / m³) 3 Low grade (<0.5g / m) 3 The use of three types of solutions facilitates targeted adsorption and recovery, improves overall adsorption efficiency, and shortens the adsorption cycle. Furthermore, since the calcium ion content in the precious solution varies at different spraying times, separate diversion allows solutions with similar calcium ion content to be pooled together, making subsequent targeted calcium ion inhibition and synergistic scale inhibition treatment more effective. This also avoids the presence of high levels of impurity ions (such as Fe) in low-grade precious solutions. 3+ Cu 2+ Interference with the adsorption process of high-grade precious liquids.

[0012] S2. Calcium ion targeted inhibition and synergistic scale inhibition treatment: Detect the calcium ion concentration in high, medium and low grade precious liquids, and add corresponding amounts of polyaspartic acid, sodium citrate and carboxymethyl chitosan composite scale inhibitor according to the calcium ion concentration, so that the free calcium ions in each precious liquid form soluble and stable complexes to prevent scale formation.

[0013] In heap leaching, the addition of lime to the precious liquor to adjust the pH (usually maintaining a pH of 10-11 to stabilize the gold-cyanide complex) results in a Ca²⁺ concentration as high as 1000-1200 mg / L. Calcium ions combine with CO₃²⁻ in the solution to form CaCO₃ precipitate. This CaCO₃ easily deposits on the surface of activated carbon and the inner walls of pipes in the adsorption tower, leading to activated carbon calcification and scaling of pipes. Therefore, it is necessary to preferentially form other soluble and stable complexes with the free calcium ions before the precious liquor enters the adsorption stage to prevent the formation of CaCO₃ and other deposits that cause scaling. Specifically, a ternary synergistic scale inhibition technology of "chelation-dispersion-lattice distortion" is adopted.

[0014] (1) Chelation effect (polyaspartic acid): The carboxylic acid group (-COOH) on the polyaspartic acid molecular chain forms a stable complex with Ca²⁺ (complexation constant logK=8.2), reducing the concentration of free Ca²⁺ to <50 mg / L and inhibiting the nucleation of CaCO3.

[0015] (2) Dispersion effect (sodium citrate): Sodium citrate disperses microcrystalline particles through electrostatic repulsion (Zeta potential drops from +5mV to -25mV), preventing them from agglomerating and growing (particle size <50nm) and avoiding deposition.

[0016] (3) Lattice distortion (carboxymethyl chitosan): Carboxymethyl chitosan (substitution degree ≥80%) adsorbs on the surface of CaCO3 crystal nuclei, interfering with the directional growth of crystals and causing the crystal structure to change from dense calcite (density 2.71-2.83 g / cm³) to loose aragonite (density 2.93-2.95 g / cm³), which is easily dispersed by liquid flow and prevents deposition.

[0017] This ternary synergistic scale inhibition technology combines polyaspartic acid, sodium citrate, and carboxymethyl chitosan, breaking through the efficiency bottleneck of traditional single agents. It has a high scale inhibition rate, and with the graded quality of the precious liquid, the amount of scale inhibitor can be adjusted in a targeted manner to ensure effective inhibition of calcium ion scaling with low agent consumption, thus solving the impact of calcium ions on adsorption and spraying systems.

[0018] S3, Cross-group dynamic carbon circulation gradient adsorption: High, medium and low grade precious liquids treated with composite scale inhibitors are transferred to the corresponding adsorption tower groups (i.e. high grade adsorption tower group, medium grade adsorption tower group and low grade adsorption tower group) at different adsorption flow rates for activated carbon adsorption, and each adsorption tower group consists of multiple adsorption towers connected in series.

[0019] As the adsorption process proceeds, the activated carbon grade in each adsorption tower group exhibits a gradient distribution from high to low along the liquid flow direction. During this process, cross-group scheduling and circulation of gold-loaded carbon is necessary. Specifically, when the gold loading of the carbon in the high-grade adsorption tower group reaches the saturation threshold (≥8 kg / t), the saturated carbon is discharged. Then, carbon with a relatively high gold loading grade from the medium-grade adsorption tower group is transferred to the high-grade adsorption tower group, and then carbon with a relatively high gold loading grade from the low-grade adsorption tower group is transferred to the medium-grade adsorption tower group. Finally, new or regenerated carbon is then used... The activated carbon is added to the low-grade adsorption tower group, and the entire scheduling cycle operation always follows the principle that "the grade of gold-loaded carbon in each adsorption tower group is distributed in a gradient from high to low according to the direction of liquid flow". This is repeated, and the high-grade precious liquid is always in contact with the high-grade gold-loaded carbon. The gold-loaded carbon is quickly saturated, and the remaining gold ions are forced to migrate to the low-grade gold-loaded carbon, forming a directional concentration difference driving force. This achieves the effect of precise matching between grade and adsorption efficiency, shortens the adsorption equilibrium time, and improves the overall adsorption rate. Finally, the lean liquid remaining after activated carbon adsorption can be reused for spraying in the stockpile.

[0020] This step optimizes the adsorption flow rate of high-, medium-, and low-grade precious liquors based on their different adsorption behaviors to ensure adsorption effect and efficiency, as detailed below:

[0021] The high-grade precious liquid is rapidly passed through the adsorption tower at a high flow rate (25 m³ / h). Utilizing the remaining adsorption sites on the highly gold-loaded carbon, the adsorption of the main gold content is completed within a short contact time (adsorption rate constant k = 0.48 min⁻¹). This avoids the high concentration of gold ions from remaining in the tower for too long, which could lead to local saturation of the carbon surface (the mass transfer boundary layer thickness is reduced by 50% at high flow rates, thus improving the diffusion rate).

[0022] The medium-grade precious liquid was applied at a moderate flow rate (17 m³ / h) to extend the liquid-carbon contact time (25% higher at higher rates), ensuring that medium-concentration gold ions fully migrated into the carbon pores. This flow rate matched the adsorption capacity of the medium-grade carbon with its gold loading, balancing efficiency and adsorption depth.

[0023] The low-grade precious solution is operated at a low flow rate (10 m³ / h). By extending the residence time (60% higher than the rate), the low-concentration gold ions are fully adsorbed on the gold-supported carbon, overcoming the problem of insufficient diffusion driving force at low concentrations.

[0024] Adsorption operations were carried out in stages using different adsorption flow rates and gold-loaded carbon grades from high to low.

[0025] This step employs a coupling mechanism of "gradient adsorption-gold-loaded carbon cross-group scheduling and circulation" to achieve cross-group circulation of carbon resources and reconstruction of adsorption gradients, forming a multi-dimensional synergistic effect mechanism. This overcomes the limitations of traditional adsorption towers operating independently, ensuring that the high-grade precious liquid is always in contact with the high-gold-loaded carbon (tower 1). The high concentration of gold is rapidly adsorbed by the high-gold-loaded carbon to reach saturation, while the remaining gold ions continue to migrate to the low-gold-loaded carbon, forming a directional concentration difference driving force. This achieves a precise match between grade and adsorption efficiency, shortens the adsorption equilibrium time, improves the overall adsorption rate, and shortens the adsorption cycle.

[0026] Furthermore, in step S1, the grades of the high, medium, and low-grade precious liquors (i.e., the gold content in the precious liquors) are greater than 1.5 g / m³. 3 0.5~1.5g / m 3 Less than 0.5g / m 3 .

[0027] Furthermore, in step S2, the amount of composite scale inhibitor added is calculated based on the calcium ion consumption. If the calcium ion concentration in the liquid is less than 300 mg / L, polyaspartic acid, sodium citrate, and carboxymethyl chitosan are added at a consumption of 1.5 mg / mg, 0.4 mg / mg, and 0.1 mg / mg, respectively. If the calcium ion concentration in the liquid is greater than 300 mg / L, polyaspartic acid, sodium citrate, and carboxymethyl chitosan are added at a consumption of 1.8 mg / mg, 0.5 mg / mg, and 0.2 mg / mg, respectively.

[0028] Furthermore, in step S3, the adsorption flow rates of the high, medium, and low grade precious liquids are 25 m³ / h, 17 m³ / h, and 10 m³ / h, respectively.

[0029] The present invention also provides a system for the above-mentioned dynamic circulating cascade adsorption gold extraction process using a fractional flow of precious liquor, comprising multiple heap leaching fields, each heap leaching field being connected to a No. 1 precious liquor pipe, a No. 2 precious liquor pipe, and a No. 3 precious liquor pipe. Valves are installed on all No. 1 precious liquor pipes, all No. 2 precious liquor pipes are connected to a No. 1 stirring tank, all No. 2 precious liquor pipes are connected to a No. 2 stirring tank, and all No. 3 precious liquor pipes are connected to a No. 3 stirring tank. The No. 1, No. 2, and No. 3 stirring tanks are respectively connected to the No. 1, No. 2, and No. 3 precious liquor pools via gravity flow pipes. The No. 1, No. 2, and No. 3 precious liquor pools are respectively connected to the No. 1, No. 2, and No. 3 adsorption tower groups via delivery pipes and delivery pumps, and flow meters are installed on the delivery pipes.

[0030] Furthermore, each of the adsorption tower group #1, adsorption tower group #2, and / or adsorption tower group #3 consists of five adsorption towers connected in series.

[0031] The beneficial effects of this invention are as follows: This invention overcomes the long-standing problems of grade dilution, calcium deposition, and low carbon adsorption efficiency in the field of heap leaching precious liquor adsorption through a multi-dimensional synergistic enhancement technology of "precious liquor fractionation and diversion - calcium ion targeted inhibition and synergistic scale inhibition - cross-group dynamic carbon circulation gradient adsorption," achieving a synergistic improvement in gold recovery rate, economic benefits, and environmental benefits. Specifically, this is reflected in the following aspects:

[0032] (1) Optimize adsorption efficiency: By implementing fractional adsorption of precious liquor, a precise match between concentration and adsorption efficiency is achieved, avoiding the problems of dilution of high-grade precious liquor and insufficient adsorption of low-grade precious liquor. At the same time, the optimization of adsorption kinetics is achieved through gradient utilization of carbon resources and precise process control, thereby improving the overall adsorption efficiency.

[0033] (2) Reduce the impact of calcium ions: By combining polyaspartic acid, sodium citrate and carboxymethyl chitosan through the multi-mechanism ternary synergistic scale inhibition technology of "chelation-dispersion-lattice distortion", the efficiency bottleneck of traditional single agent is broken through, the scale inhibition rate is improved, the impact of calcium ions on adsorption and spraying systems is effectively solved, and the problems of activated carbon calcification and pipe scaling are reduced.

[0034] (3) Improve the grade of gold-loaded carbon: Through the coupling mechanism of "gradient adsorption-cross-group circulation", cross-group circulation of carbon resources and adsorption gradient reconstruction are realized, breaking through the limitations of independent operation of traditional adsorption towers. High-grade precious liquid is always in contact with high-grade gold-loaded carbon, and high-concentration gold is quickly adsorbed to saturation. The remaining gold ions migrate to low-grade gold-loaded carbon, forming a directional concentration difference driving force, which shortens the adsorption equilibrium time, improves the overall adsorption rate, and shortens the adsorption cycle.

[0035] (4) Resource recycling: Through cross-group dynamic carbon recycling, the resource recycling of gold-loaded carbon has been upgraded, the overall gold loading of the carbon has been increased, and energy consumption, reagents and maintenance costs have been reduced. At the same time, the lean liquor after adsorption can be reused for field spraying, realizing the recycling of resources and reducing production costs. Attached Figure Description

[0036] Figure 1 This is a flowchart of a dynamic circulating ladder adsorption process for gold extraction using a fractional flow of precious liquids according to the present invention.

[0037] Figure 2 This is an equipment association diagram of a dynamic circulating cascade adsorption gold extraction process system for precious liquid fractionation and diversion according to the present invention;

[0038] In the diagram: 1-Heap leaching field; 21-Precious liquor pipe #1, 22-Precious liquor pipe #2, 23-Precious liquor pipe #3; 31-Agitator #1, 32-Agitator #2, 33-Agitator #3; 41-Precious liquor pool #1, 42-Agitator #2, 43-Agitator #3; 51-Adsorption tower group #1, 52-Agitator group #2, 53-Agitator group #3; 6-Gravity flow pipe; 7-Transfer pipe; 8-Transfer pump; 9-Flow meter. Detailed Implementation

[0039] To make the technical problems and solutions solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Example 1

[0040] For heap leaching fields 1-3 of a certain mine, field 1 is the initial spraying stage with a precious liquor grade of 2.0 g / m³ and a calcium ion concentration of 1100 mg / L; field 2 is the intermediate spraying stage with a precious liquor grade of 1.2 g / m³ and a calcium ion concentration of 700 mg / L; and field 3 is the late spraying stage with a precious liquor grade of 0.3 g / m³ and a calcium ion concentration of 200 mg / L. Using traditional processes, the average grade of the precious liquor after mixing is only 0.96 g / m³, and the grade of the gold-loaded carbon after adsorption is 2100 g / t. Problems such as precious liquor grade dilution, activated carbon calcification and caking, and long adsorption cycle (about 25 days) are faced.

[0041] like Figure 1 As shown, the process described in this invention for treating the above-mentioned precious liquid includes the following steps:

[0042] S1. Precious liquor separation and diversion: During heap leaching, the grade of the precious liquor in the heap is monitored. Based on the grade, high, medium, and low grades of precious liquor are separated and diverted to different mixing tanks. The grade of the collected high-grade precious liquor is 2 g / m³. 3 The grade of the medium-grade precious liquor is 1.2 g / m³. 3 The grade of the low-grade precious liquor is 0.3 g / m³. 3 .

[0043] S2, Calcium ion targeted inhibition and synergistic scale inhibition: The calcium ion concentrations in high, medium and low grade precious liquids were 1100 mg / L, 700 mg / L and 200 mg / L, respectively. Based on the calcium ion concentration, polyaspartic acid, sodium citrate, and carboxymethyl chitosan were added to the high-grade and medium-grade precious solutions at unit consumption rates of 1.8 mg / mg, 0.5 mg / mg, and 0.2 mg / mg, respectively; while in the low-grade precious solution, they were added at unit consumption rates of 1.5 mg / mg, 0.4 mg / mg, and 0.1 mg / mg, respectively. After addition, the solution was stirred for 30 minutes to allow the free calcium ions to fully react and form soluble and stable complexes. At this point, the concentrations of free calcium ions in the high, medium, and low-grade precious solutions were 45 mg / L, 36 mg / L, and 12 mg / L, respectively. Compared with the traditional process, the amount of CaCO3 and other precipitates was reduced by more than 94%, effectively inhibiting scale formation and significantly reducing the risk of activated carbon and pipeline calcification.

[0044] S3. Cross-group dynamic carbon circulation gradient adsorption: High-grade, medium-grade, and low-grade precious liquids treated with composite scale inhibitors are transferred to corresponding adsorption tower groups (i.e., high-grade adsorption tower group A1-A5, medium-grade adsorption tower group B1-B5, and low-grade adsorption tower group C1-C5) at different adsorption flow rates for activated carbon adsorption. Each group consists of 5 adsorption towers connected in series. Specifically, the high-grade precious liquid passes through the adsorption tower at a flow rate of 25 m³ / h, the medium-grade precious liquid at a flow rate of 17 m³ / h, and the low-grade precious liquid at a flow rate of 10 m³ / h.

[0045] As the adsorption operation proceeds, the activated carbon grade in each adsorption tower group exhibits a gradient distribution from high to low according to the liquid flow direction. During this process, by detecting the grade of gold-loaded carbon, after 10 days of adsorption, the gold loading of the carbon in tower A1 of the high-grade adsorption tower group reaches the saturation threshold (≥8kg / t). The saturated carbon in tower A1 is then unloaded. Then, according to the grade of gold-loaded carbon in each remaining group, the schedule is adjusted. Specifically, A2→A1, A3→A2, and B1→A3 form high-grade adsorption tower groups, B2→B1, B3→B2, and C1→B3 form medium-grade adsorption tower groups, and C2→C1, C3→C2, C4→C3, C5→C4, and C5 are loaded with new carbon or lean carbon to form low-grade adsorption groups. This process of dynamic scheduling of gold-loaded carbon across groups is repeated, and the entire scheduling cycle always follows the principle that "the grade of gold-loaded carbon in each adsorption tower is distributed in a gradient from high to low according to the direction of liquid flow" until all the precious liquid to be treated has been adsorbed.

[0046] The "separate flow-calcium ion targeted inhibition synergistic scale inhibition-cross-group dynamic carbon circulation gradient adsorption" process technology employed in the method of this invention can effectively inhibit scale formation, greatly reduce the impact of calcium ions on adsorption and spraying operations, and significantly improve the adsorption efficiency of activated carbon by controlling the adsorption flow rate of precious solutions of different grades and the grade of gold-loaded carbon. The actual improvement in process indicators is as follows:

[0047] (1) Increased gold loading and reduced carbon consumption: The grade of gold-loaded carbon increased from 2000-3000 g / t to over 8000 g / t, representing an increase of 266%-400%. Through dynamic carbon circulation scheduling, the overall adsorption rate constant increased by 37% (from 0.35 to 0.48 min). -1 The carbon reuse rate reaches 92% (compared to ≤75% with traditional processes), the number of carbon cycles increases from 3-5 times to 8-10 times, and the carbon replacement cost is reduced by 50%.

[0048] (2) Shortened adsorption cycle: The adsorption cycle of activated carbon has been reduced from 20-30 days to 10 days, which is about 50%-70% shorter, greatly improving production efficiency.

[0049] (3) Improved scale inhibition efficiency: Free Ca in the solution ²+ When the concentration decreases from 1000-1200 mg / L to less than 50 mg / L, free Ca ²+ The concentration was reduced by more than 94%. The scaling rate of activated carbon, pipes, and nozzles was greatly reduced, significantly improving the efficiency of spraying and reducing the frequency of nozzle replacement and maintenance.

[0050] (4) The cost of gold-loaded carbon analysis is reduced and the overall gold recovery rate is improved. After the grade of gold-loaded carbon is improved, the overall cost of gold analysis per gram is reduced by about 65%, and the overall gold recovery rate is increased by about 1.2%. Example 2

[0051] like Figure 2 As shown, this embodiment provides a system for the above-mentioned dynamic circulating cascade adsorption gold extraction process using a fractional flow of precious liquor, including multiple heap leaching fields 1. Each heap leaching field 1 is connected to a 1# precious liquor pipe 21, a 2# precious liquor pipe 22, and a 3# precious liquor pipe 23. Valves are installed on all 1# precious liquor pipes 21, 2# precious liquor pipes 22, and 3# precious liquor pipes 23. All 1# precious liquor pipes 21 are connected to a 1# stirring tank 31, and all 2# precious liquor pipes 22 are connected to a 2# stirring tank 32. All three precious liquid pipes 23 are connected to the third stirring tank 33. The first stirring tank 31, the second stirring tank 32, and the third stirring tank 33 are connected to the first precious liquid tank 41, the second precious liquid tank 42, and the third precious liquid tank 43 respectively via gravity flow pipes 6. The first precious liquid tank 41, the second precious liquid tank 42, and the third precious liquid tank 43 are connected to the first adsorption tower group 51, the second adsorption tower group 52, and the third adsorption tower group 53 respectively via delivery pipes 7 and delivery pumps 8. Flow meters 9 are installed on each delivery pipe 7. Each of the first adsorption tower group 51, the second adsorption tower group 52, and / or the third adsorption tower group 53 consists of five adsorption towers connected in series.

[0052] Among them, the volume of No. 1 precious liquid tank 41, No. 2 precious liquid tank 42 and No. 3 precious liquid tank 43 is 300m³. 3 The dimensions of mixing tanks 1# (31), 2# (32), and 3# (33) are Ø4×4m; the height of the adsorption tower is Ø1×3m. Of course, the dimensions of the above equipment are not limited to Yuci and can be adjusted according to actual needs.

[0053] It should also be noted that all the equipment involved in this implementation is existing equipment. This implementation only involves the application of these devices and does not involve structural modifications to the equipment.

[0054] When using this system to treat precious liquor in heap leaching, the grade of the precious liquor should be checked regularly during the heap leaching process. The grade of the precious liquor should be >1.5 g / m³. 3 At this time, close the valves on the No. 2 precious liquid pipe 22 and the No. 3 precious liquid pipe 23, and allow the high-grade precious liquid to flow from the No. 1 precious liquid pipe 21 to the No. 1 stirring tank 31; if the precious liquid grade is 0.5~1.5g / m 3 In between, close the valves on the No. 1 precious liquid pipe 21 and the No. 3 precious liquid pipe 23, allowing the medium-grade precious liquid to flow from the No. 2 precious liquid pipe 22 to the No. 2 stirring tank 32; if the precious liquid grade is <0.5g / m 3Close the valves on the No. 1 precious liquid pipe 21 and the No. 2 precious liquid pipe, and allow the low-grade precious liquid to flow from the No. 3 precious liquid pipe 23 to the No. 3 mixing tank 33. Repeat this cycle so that the high-grade, medium-grade, and low-grade precious liquids are collected in the No. 1 mixing tank 31, the No. 2 mixing tank 32, and the No. 3 mixing tank 33, respectively.

[0055] Based on the calcium ion concentrations in the high-grade, medium-grade, and low-grade precious liquids, appropriate scale inhibitors (polyaspartic acid, sodium citrate, and carboxymethyl chitosan) are added to stirring tanks 1#31, 2#32, and 3#33, and the mixture is stirred thoroughly to allow the free calcium ions in each precious liquid to form soluble and stable complexes, thereby preventing the deposition and scaling of substances such as CaCO3.

[0056] After treatment with a composite scale inhibitor, the high-grade, medium-grade, and low-grade precious solutions, having had calcium ions removed, are transferred via conveying pipes 7 and pumps 8 connected to the outlets of each mixing tank to adsorb calcium ions onto adsorption tower groups 1 (51), 2 (52), and 3 (53), respectively, for activated carbon adsorption. During the transport process, the flow rate of each precious solution is monitored by corresponding flow meters 9 to ensure that the high-grade solution passes through the adsorption tower at a flow rate of 25 m³ / h, the medium-grade solution at 17 m³ / h, and the low-grade solution at 10 m³ / h.

[0057] During the adsorption process, the gold-loaded carbon that is saturated with adsorption is unloaded in a timely manner, and the remaining gold-loaded carbon is dynamically scheduled across groups according to the principle of "the grade of gold-loaded carbon in each adsorption tower is distributed in a gradient from high to low according to the direction of liquid flow" to ensure precise matching between grade and adsorption efficiency, improve the overall adsorption rate, and shorten the adsorption cycle.

[0058] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic circulating stepped adsorption process for gold extraction using a fractional-flow noble liquid, characterized in that, Includes the following steps: S1. Precious liquor separation and diversion: During the heap leaching process, the grade of the precious liquor in the heap is detected, and high, medium and low grade precious liquors are separated according to the grade and diverted to different mixing tanks respectively. S2. Calcium ion targeted inhibition and synergistic scale inhibition treatment: Detect the calcium ion concentration in high, medium and low grade precious liquids, and add corresponding amounts of polyaspartic acid, sodium citrate and carboxymethyl chitosan composite scale inhibitor according to the calcium ion concentration, so that the free calcium ions in each precious liquid form soluble and stable complexes to prevent scale formation. S3. Cross-group dynamic carbon circulation gradient adsorption: High, medium, and low grade precious liquids treated with composite scale inhibitors are transferred to corresponding adsorption tower groups at different adsorption flow rates for activated carbon adsorption. Each adsorption tower group consists of multiple adsorption towers connected in series. As the adsorption operation proceeds, the activated carbon grade in each adsorption tower group exhibits a gradient distribution from high to low according to the liquid flow direction. During this process, cross-group scheduling and circulation of gold-loaded carbon is required. Specifically, when the gold loading of carbon in the high-grade adsorption tower group reaches the saturation threshold, the saturated carbon is unloaded. Then, carbon with a relatively high gold loading grade from the medium-grade adsorption tower group is transferred to the high-grade adsorption tower group, and then the low-grade carbon is transferred to the medium-grade adsorption tower group. The gold-loaded carbon with relatively high grade in the high-grade adsorption tower group is transferred to the medium-grade adsorption tower group, and finally, new or regenerated carbon is added to the low-grade adsorption tower group. The entire scheduling cycle operation always follows the principle that "the gold-loaded carbon grade in each adsorption tower group is distributed in a gradient from high to low according to the liquid flow direction". This process is repeated, and the high-grade precious liquid is always in contact with the high-grade gold-loaded carbon, which quickly becomes saturated. The remaining gold ions are forced to migrate to the low-grade gold-loaded carbon, forming a directional concentration difference driving force, achieving a precise match between grade and adsorption efficiency, shortening the adsorption equilibrium time, and improving the overall adsorption rate. Finally, the lean liquid remaining after activated carbon adsorption can be reused for spraying in the stockpile.

2. The gold extraction process for precious liquid fractionation and dynamic circulation stepwise adsorption according to claim 1, characterized in that, The grade of high, medium and low grade noble liquid in step S1 is respectively greater than 1.5 g / m 3 , 0.5-1.5 g / m 3 , and less than 0.5 g / m 3 .

3. The gold extraction process for precious liquid fractionation and dynamic circulation stepped adsorption according to claim 1, characterized in that, In step S2, the amount of composite scale inhibitor added is calculated based on the calcium ion consumption. If the calcium ion concentration in the liquid is less than 300 mg / L, polyaspartic acid, sodium citrate, and carboxymethyl chitosan are added at a consumption of 1.5 mg / mg, 0.4 mg / mg, and 0.1 mg / mg, respectively. If the calcium ion concentration in the liquid is greater than 300 mg / L, polyaspartic acid, sodium citrate, and carboxymethyl chitosan are added at a consumption of 1.8 mg / mg, 0.5 mg / mg, and 0.2 mg / mg, respectively.

4. The gold extraction process for a precious liquid with fractional flow dynamic circulation staged adsorption according to claim 2, characterized in that, In step S3, the adsorption flow rates of the high, medium, and low grade precious liquids are 25 m³ / h, 17 m³ / h, and 10 m³ / h, respectively.

5. The system for a dynamic circulating stepped adsorption gold extraction process using a fractional flow of precious liquid as described in any one of claims 1-4, characterized in that, It includes multiple heap leaching fields (1), each of which is connected to a No. 1 precious liquid pipe (21), a No. 2 precious liquid pipe (22), and a No. 3 precious liquid pipe (23). All No. 1 precious liquid pipes (21), No. 2 precious liquid pipes (22), and No. 3 precious liquid pipes (23) are equipped with valves. All No. 1 precious liquid pipes (21) are connected to a No. 1 stirring tank (31), all No. 2 precious liquid pipes (22) are connected to a No. 2 stirring tank (32), and all No. 3 precious liquid pipes (23) are connected to a No. 3 stirring tank (33). 3) The mixing tanks 1# (31), 2# (32) and 3# (33) are connected to the precious liquid tanks 1# (41), 2# (42) and 3# (43) respectively via gravity flow pipes. The precious liquid tanks 1# (41), 2# (42) and 3# (43) are connected to the adsorption tower group 1# (51), 2# (52) and 3# (53) respectively via conveying pipes and conveying pumps. Flow meters (6) are installed on the conveying pipes.

6. The system for a dynamic circulating stepped adsorption gold extraction process using a fractional flow of precious liquid according to claim 5, characterized in that, Adsorption tower group 1 (51), adsorption tower group 2 (52) and adsorption tower group 3 (53) are all composed of 5 adsorption towers connected in series.

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