Process for treating low-grade gold ore by blasting permeation and synergistic leaching

Abstract

This application provides a process for synergistic leaching of low-grade gold ore using blasting and permeation enhancement, belonging to the fields of hydrometallurgy and mining engineering. The process involves drilling and charging explosives on the ore body benches, employing a wide-spacing, low-resistance-line hole layout to create a blasted ore heap. A gold leaching reagent system, adjusted to alkaline pH, is applied as a solution to the surface of the blasted ore heap. The reagent system includes sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate. The spray intensity of the reagent solution is controlled to allow it to permeate through the fracture network created by the blasting, reacting with the gold minerals. The permeated solution is collected and recycled. After leaching, the tailings are sampled and tested to assess the gold leaching rate. This application achieves a highly efficient synergistic effect between the advantageous permeation field created by physical blasting and the chemical permeation, catalysis, and stabilization functions of the reagent system, thereby enhancing the gold leaching rate.

Description

Technical Field

[0001] This invention relates to the fields of hydrometallurgy and mining engineering technology, specifically to a process for blasting-enhanced leaching combined with blasting to treat low-grade gold ore. Background Technology

[0002] The core of in-situ gold leaching technology relies on the dissolution of gold in the ore by the leaching agent. However, low-grade ores usually have poor permeability, complex gold occurrence state, and contain interfering impurities, which leads to inherent defects in conventional leaching processes such as hindered agent diffusion, insufficient effective contact area, long leaching cycle, and low final recovery rate, which seriously restricts its economic feasibility.

[0003] To improve leaching efficiency, existing technologies are mainly optimized in two directions: first, by modifying the formulation of gold leaching agents to enhance selectivity or tolerance, but this has limited effect on improving the macroscopic permeability of the ore body; second, by attempting to pretreat the ore body through physical, chemical, or biological methods to increase permeability. Blasting technology has significant potential in altering the ore-rock structure, but traditional blasting methods struggle to accurately generate a fracture network conducive to fluid penetration, and are prone to causing local over-crushing or fracture closure. Furthermore, they lack a systematic process design that works synergistically with specific gold leaching agent systems, leading to a disconnect between the permeation enhancement and leaching stages, thus failing to achieve a technological breakthrough in the efficient and low-cost treatment of low-grade gold ores.

[0004] In view of this, it is necessary to design a process for blasting-enhanced permeability leaching combined with leaching to treat low-grade gold ore in order to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides a process for blasting-enhanced leaching combined with blasting to treat low-grade gold ore, which aims to solve the technical problems of low leaching rate and poor reagent stability caused by poor permeability and the disconnect between blasting and leaching in existing in-situ leaching processes for low-grade gold ore.

[0006] This application provides a process for blasting-enhanced leaching combined with leaching to treat low-grade gold ore, comprising the following steps: S1. Drilling and charging are carried out on the ore body bench, and blasting is carried out using a wide-spacing, low-resistance-line hole layout. The parameters of the wide-spacing, low-resistance-line hole layout include: hole spacing 3~5m, row spacing 1.5~4m, hole inclination angle 50~70°, hole over-depth 0.3~1.0m, and hole diameter 120~160mm. The hole density coefficient m of the blasting is determined by block size analysis through numerical simulation, where m = hole spacing / row spacing. Based on the statistical distribution of damage variables, the damage value D in the ore rock after blasting is kept in the range of 0.2~0.8, forming a blasted ore pile. S2. After adjusting the pH of the gold leaching agent system to alkaline, apply it to the surface of the blasted ore pile in solution form; the gold leaching agent system includes sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate; S3. Control the spraying intensity of the chemical solution so that the chemical solution seeps into the fracture network formed by the blasting, reacts with the gold minerals, and the seeping precious liquid is collected and sprayed again. S4. After leaching, the tailings are sampled and tested to assess the gold leaching rate.

[0007] As a further improvement to this application, the concentration of sodium thiosulfate is 30~50 g / L.

[0008] As a further improvement to this application, the concentration of N-(γ-glutamyl)ethanolamine is 15~30 g / L.

[0009] As a further improvement to this application, the concentration of sodium tartrate is 50~75 g / L.

[0010] As a further improvement to this application, the pH of the immersion gold reagent system is 8.0~10.0.

[0011] As a further improvement of this application, the borehole density coefficient of the wide-spacing, small-resistance-line borehole arrangement is 1.0~2.0.

[0012] As a further improvement of this application, in step S1, the blasting adopts a micro-delay initiation, with an inter-row delay time of 40~70ms and an inter-hole delay time of 15~30ms.

[0013] As a further improvement of this application, in step S3, the spraying intensity of the pharmaceutical solution is 5~15 L / m. 2 •h, the leaching cycle is 60~120 days.

[0014] As a further improvement to this application, in step S4, the gold leaching rate η is calculated using the following formula: η= [(m1×β1) - (m2×β2)] / (m1×β1) ×100%; Wherein, β1 is the average grade of the original leached mineral sample, β2 is the grade of the tailings sample, m1 is the total mass of the original leached mineral sample, and m2 is the total mass of the tailings after leaching.

[0015] The beneficial effects of this application are as follows: This application provides a process for synergistic leaching and permeation enhancement treatment of low-grade gold ore. The process involves drilling and charging explosives on the ore body benches, employing a wide-spacing, low-resistance-line hole layout to create a blasted ore heap. A gold leaching reagent system, adjusted to alkaline pH, is applied as a solution to the surface of the blasted ore heap. The reagent system includes sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate. The spray intensity of the reagent solution is controlled to allow it to permeate through the fracture network created by the blasting, reacting with the gold minerals. The permeated solution is collected and recycled. After leaching, the tailings are sampled and tested to assess the gold leaching rate. This application combines an optimized gold leaching reagent system with controlled blasting permeation enhancement technology to form a highly efficient synergistic treatment process. This process first constructs a well-developed physical fracture network within the ore body through precise blasting, significantly improving the initial permeability of the ore body. Building upon this foundation, the gold leaching reagent system used in this application not only efficiently dissolves gold, but its unique chemical composition also reacts with minerals or fracture surfaces in the ore, further dissolving or modifying impurities clogging pores, achieving a synergistic enhancement of physical blasting-induced permeability and chemical permeability enhancement. This dual permeability enhancement mechanism significantly optimizes the transport channels and reaction interfaces of the leaching agent, ensuring rapid and uniform penetration and sufficient contact with the target mineral. Compared to traditional single methods, this process significantly improves leaching efficiency, gold recovery rate, and resource utilization, while effectively controlling operating costs, providing a complete solution for the economical and green development of low-grade gold mines.

[0016] The core innovation of this application lies in combining a physical blasting scheme based on simulation and precise optimization with a reagent system that has in-situ catalysis and chemical permeation enhancement functions to construct an integrated solution of physical permeation enhancement, chemical unblocking, and stable leaching. This solution systematically solves the problem of low resource utilization of low-permeability gold-bearing ore bodies from two dimensions: macroscopic mass transfer conditions and microscopic reaction environment.

[0017] The key to this process lies in determining the optimal combination of blasting parameters through detailed numerical simulations. By comparing damage contour maps and block size distribution curves under different borehole spacings (1.6m to 4m), the optimization objective was clearly defined as maximizing the proportion of ore volume within the optimal range of damage value D. When using a wide borehole spacing and small resistance line scheme with a borehole spacing of 4m and a row spacing of 3m (density coefficient of approximately 1.33), the ratio of large blocks to fine ore can be balanced most effectively, forming an ore structure dominated by interconnected fractures and with uniform block size. This provides a superior seepage channel and a large effective reaction surface area for the subsequent leaching reagent system, physically solving the core bottleneck of insufficient reagent contact and slow leaching kinetics in traditional processes.

[0018] Building upon this physical foundation, the reagent system of this application leverages chemical synergistic effects to enhance penetration and stabilize leaching. Sodium tartrate in the reagent preferentially complexes iron minerals in the ore, continuously releasing Fe in situ. 2+ / Fe 3+ Ions form highly efficient and renewable catalytic centers, driving the selective oxidation of gold. Simultaneously, this complexation process slightly dissolves ore components on the surface of the ore fissures, achieving active chemical permeation and further unclogging and expanding micropores. N-(γ-glutamyl)ethanolamine acts as a system stabilizer, effectively inhibiting the deactivation of the active component (sodium thiosulfate) in the reagent system through synergistic effects between the reagent systems, preventing its conversion into insoluble sulfur-containing substances (such as elemental sulfur, disulfide compounds, etc.), ensuring the long-term and stable permeation reaction of gold leaching within the complex fracture network. Ultimately, the advantageous seepage field formed by physical blasting and the chemical permeation, catalysis, and stabilization functions of the reagent system work synergistically to improve the gold leaching rate while significantly reducing reagent consumption and processing costs per unit ore, providing a technological path for the economical and green development of low-grade, difficult-to-permeable gold resources.

[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0021] Figure 1 This is a process flow diagram of blasting-enhanced leaching combined with leaching for treating low-grade gold ore, provided in an embodiment of this application. Figure 2 This is a photograph of the chemically eroded small-sized ore body after leaching in Example 1 of this application; Figure 3 The statistical results in this embodiment are based on the damage volume distribution. Detailed Implementation

[0022] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0026] Low-grade gold deposits suffer from poor permeability and complex gold occurrence, leading to drawbacks in conventional leaching processes such as hindered reagent diffusion, insufficient effective contact area, long leaching cycles, and low recovery rates. Existing technologies primarily optimize these processes in two ways: first, by improving reagents to enhance selectivity, but this has limited effect on improving the macroscopic permeability of the ore body; second, by employing physical methods such as blasting for pretreatment to enhance permeability, but traditional blasting struggles to accurately create a fracture network conducive to fluid penetration and is disconnected from subsequent leaching stages, lacking a systematic and coordinated design, thus failing to achieve efficient and low-cost development of low-grade gold deposits.

[0027] To address the technical problems of low leaching rates and poor reagent stability in existing in-situ leaching processes for low-grade gold ores due to poor permeability and disconnect between blasting and leaching, this application provides a process for synergistic leaching of low-grade gold ores using blasting-enhanced permeability. This process employs precise blasting with wide-spacing and small resistance lines, optimized for damage variables, to construct a uniformly interconnected fracture network within the ore body. Combined with a gold leaching reagent system comprising sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate, sodium tartrate in-situ complexes and dissolves iron ions from the ore to form a catalytic center, while N-(γ-glutamyl)ethanolamine stabilizes the active components of the gold leaching system. Simultaneously, chemical dissolution expands the microfractures. This achieves the technical effects of synergistic enhancement of physical permeability through blasting and chemical permeability through reagents, significantly improving the leaching agent penetration rate and gold leaching rate, and effectively reducing reagent consumption.

[0028] This application provides a process for treating low-grade gold ore by blasting and permeation enhancement combined with leaching, including the following steps: S1. Drilling and charging are carried out on the ore body bench. Blasting is carried out using a wide-spacing, low-resistance-line hole layout. The parameters of the wide-spacing, low-resistance-line hole layout include: hole spacing 3~5m, row spacing 1.5~4m, hole inclination angle 50~70°, hole over-depth 0.3~1.0m, and hole diameter 120~160mm. The blasting hole density coefficient m is determined by block size analysis through numerical simulation, where m = hole spacing / row spacing. Based on the statistical distribution of damage variables, the damage value D in the ore rock after blasting is kept in the range of 0.2~0.8, forming a blasted ore pile. S2. After adjusting the pH of the gold leaching agent system to alkaline, apply it to the surface of the blasted ore pile in solution form; the gold leaching agent system includes sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate; S3. Control the spraying intensity of the chemical solution so that the chemical solution seeps into the fracture network formed by the blasting, reacts with the gold minerals, and the seeping precious liquid is collected and sprayed again. S4. After leaching, the tailings are sampled and tested to assess the gold leaching rate.

[0029] In the technical solution of this application embodiment, the blasting parameters with wide hole spacing and small resistance line are optimized through numerical simulation. After blasting, a superior seepage network is formed in the ore body, mainly composed of large-sized interconnected fractures, with uniform block size and low ore fines ratio, thus overcoming the bottleneck of poor primary permeability of low-grade gold ore from a physical perspective. On this basis, a gold leaching agent system containing sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate is applied. Sodium tartrate preferentially complexes iron minerals in the ore, releasing iron ions in situ to form a catalytic redox couple, driving sodium thiosulfate to activate and dissolve gold. Meanwhile, N-(γ-glutamyl)ethanolamine stabilizes thiosulfate and gold complexes in solution through the synergistic coordination stabilization effect of its amide and amino groups, effectively inhibiting the ineffective decomposition of sodium thiosulfate into byproducts such as tetrathionate and the tendency of gold ions to be reduced and reprecipitated, thus ensuring the high efficiency and stability of the main leaching reaction. The fracture network constructed by physical blasting provides a rapid permeation channel for the reagent solution. During the permeation process, the reagent simultaneously exerts the functions of catalytic gold leaching and chemical permeation enhancement, with the two working synergistically to achieve efficient leaching of low-grade gold ore.

[0030] Furthermore, in some embodiments, the concentration of sodium thiosulfate is 30-50 g / L, the concentration of N-(γ-glutamyl)ethanolamine is 15-30 g / L, and the concentration of sodium tartrate is 50-75 g / L.

[0031] In the technical solution of this application embodiment, sodium thiosulfate is used as the main gold leaching agent. A suitable concentration helps to provide sufficient leaching active species, but an excessively high concentration will cause the leaching rate to increase slowly and the reagent cost to increase significantly. N-(γ-glutamyl)ethanolamine is used as a system stabilizer. A suitable concentration can effectively inhibit the ineffective decomposition of sodium thiosulfate and the redeposition of gold. Sodium tartrate is used as a complexing iron solvent to provide a sufficient and continuous source of iron ions for the catalytic oxidation reaction. The synergistic operation of each component ensures the efficient operation of the catalytic oxidation-stabilized complexation-chemical permeation mechanism, avoids the waste of resources caused by excessive addition, and achieves the optimal synergy between process economy and leaching efficiency.

[0032] Furthermore, in some embodiments, the pH of the environment in which the gold immersion agent system is used is 8.0 to 10.0.

[0033] In the technical solution of this application embodiment, the structural stability of sodium thiosulfate is significantly enhanced in an alkaline environment, enabling it to continuously provide sufficient thiosulfate ions to participate in the coordination dissolution reaction of gold. The amide and amino groups of N-(γ-glutamyl)ethanolamine can fully exert their synergistic coordination effect under weakly alkaline conditions, effectively stabilizing thiosulfate ions and monovalent gold complexes, inhibiting the reduction and redeposition of gold and the ineffective decomposition of thiosulfate. Simultaneously, the optimal pH range for the complexation and dissolution reaction of sodium tartrate with iron minerals in the ore is also concentrated in the weakly alkaline range. By adjusting the pH of the gold leaching agent system to 8.0~10.0 with lime, the gold leaching agent system can achieve long-term stable operation in the fracture network formed by blasting.

[0034] Furthermore, in some embodiments, in step S1, the borehole density coefficient of the wide-spacing, small-resistance-line borehole layout is 1.0~2.0.

[0035] In the technical solution of this application embodiment, the optimized combination of blasting parameters can construct a ore pile structure with moderate fracture density, uniform block size, and large-sized interconnected fractures, providing the optimal physical mass transfer basis for the rapid infiltration and uniform distribution of subsequent gold leaching agents.

[0036] Furthermore, in some embodiments, in step S1, the blasting adopts a micro-delay initiation, with an inter-row delay time of 40~70ms and an inter-hole delay time of 15~30ms.

[0037] In the technical solution of this application embodiment, the reasonable inter-row delay and inter-hole delay work together to release the explosion energy in an orderly manner, effectively suppressing the problem of local energy concentration or dispersion that is prone to occur when detonation is simultaneous or the delay time is inappropriate, and finally forming a ore pile structure with large-sized interconnected fissures, uniform block size and low powder ratio.

[0038] Furthermore, in some embodiments, in step S3, the spraying intensity of the pharmaceutical solution is 5~15 L / m.2 •h, the leaching cycle is 60~120 days.

[0039] In the technical solution of this application embodiment, the coordinated matching of spray intensity and leaching cycle enables the reagent solution to maintain a suitable seepage rate and reaction time in the blasted ore pile, thereby achieving full dissolution of gold minerals and maximizing resource utilization.

[0040] Furthermore, in some embodiments, in step S4, the gold leaching rate η is calculated using the following formula: η= [(m1×β1) - (m2×β2)] / (m1×β1) ×100%; Wherein, β1 is the average grade of the original leached mineral sample, β2 is the grade of the tailings sample, m1 is the total mass of the original leached mineral sample, and m2 is the total mass of the tailings after leaching.

[0041] In the technical solution of this application embodiment, to ensure the representativeness and reliability of the measured data, a stratified random sampling method (layer spacing 2.5m) is adopted to cover the differences in tailings distribution at different depths and locations of the ore pile. The total weight of the samples is not less than one ten-thousandth of the total weight of the batch processed ore to ensure statistical representativeness. After reduction, crushing, and grinding to a particle size of less than 74μm (-200 mesh), the samples are dried at 80℃ to constant weight, so that the precision and accuracy of the subsequent fire assay for determining the tailings grade meet the requirements of the GB / T 7739 standard. At the same time, ICP-OES is used to detect the gold concentration of the circulating gold-containing precious solution. The amount of gold dissolved is calculated by using the gold concentration in the solution and the volume of the circulating liquid as an auxiliary verification method for the leaching rate. The error between the two methods is less than 1% and is considered valid data, ensuring mutual verification and high reliability of the leaching rate evaluation results, and providing reliable data support for the objective evaluation of the process effect and industrial application.

[0042] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0043] Example 1 This embodiment provides a process for the combined treatment of low-grade gold ore by explosive permeation enhancement and leaching, such as... Figure 1 As shown, it includes the following steps: S1. Based on the blasting parameters optimized by numerical simulation, drilling and charging were carried out on the ore body bench. A wide hole spacing and small resistance line layout was adopted for blasting. The hole spacing was 4m, the row spacing was 3m, the slope top width was 12m, the slope length was 16m, the slope angle was 60°, the bench height was 8.5m, and the hole layout was 4-3-4 quincunx, with a total of 11 blast holes. The blast hole inclination angle was 60°, the blast hole over-depth was 0.5m, and the hole diameter was 140mm. After charging, micro-delay blasting was carried out, with a row delay of 65ms and a hole delay of 25ms, forming a blasted ore pile with uniform block size and well-developed fractures. S2. Adjust the pH of the gold leaching agent system to 9 with lime. The concentrations of each agent in the gold leaching agent system are as follows: sodium thiosulfate solution concentration is 40 g / L, N-(γ-glutamyl)ethanolamine solution concentration is 20 g / L, and sodium tartrate solution concentration is 60 g / L. The solution is applied to the surface of the blasted ore body in solution form through the liquid distribution system. S3. Control the spray intensity of the pesticide solution to 10 L / m. 2 •h, the reagent solution seeps into the fracture network formed by the blasting, reacts with the gold mineral, and the seeping precious liquid is collected by the bottom liquid collection system and pumped to the ore body liquid distribution system. The leaching cycle is 90 days. S4. After leaching, the tailings are sampled and tested to assess the gold leaching rate.

[0044] Sampling and Sample Preparation: Monitoring points were pre-fixed, and representative tailings samples were collected using a stratified random sampling method (layer spacing 2.5m). The total weight of the samples was not less than one ten-thousandth of the total weight of the batch processed ore. The collected coarse samples were mixed, reduced in size, crushed, and ground to a particle size of less than 74μm (-200 mesh), and then dried in an 80℃ oven to constant weight to obtain analytical test samples.

[0045] Testing and Calculation: The average grade (β1, g / t) of the original leached ore sample and the grade (β2, g / t) of the prepared tailings analysis sample were determined using the fire assay method (referring to GB / T 7739). The total mass of the original leached ore sample (m1, g) and the total mass of the tailings after leaching (m2, g) were recorded by weighing. The gold leaching rate (η, %) was calculated using the following formula: η= [(m1×β1) - (m2×β2)] / (m1×β1) ×100%; Based on the calculated leaching rate η, the leaching rate of gold in the target low-grade gold ore is determined.

[0046] The gold-containing precious liquor was tested by ICP-OES, and the gold leaching rate was further verified by the gold concentration in the precious liquor. Data with an error of less than 1% between the two methods was considered valid.

[0047] like Figure 2 As shown, representative small-sized mineral samples collected in Example 1 after treatment with the gold leaching agent system exhibit obvious dissolution morphology. Figure 2 As can be seen from 'a', the particle size of the mineral sample is approximately 0.4-0.5 cm. Figure 2 As shown in b, at a scale visible to the naked eye, the ore surface exhibits roughening and localized spalling. The original microfracture openings are significantly widened due to chemical dissolution, forming more circuitous and accessible seepage channels. This phenomenon directly confirms the selective chemical dissolution effect of components such as sodium tartrate in the gold leaching reagent system on minerals in the ore fissures. It achieves secondary chemical diffusion based on the physical diffusion enhancement of blasting, significantly optimizing the microporous seepage network structure inside the ore pile, and creating favorable mass transfer conditions for deep reagent penetration and efficient gold leaching.

[0048] The blasting-based permeability enhancement process for low-grade gold deposits provided in this application uses blasting parameters determined based on numerical simulation optimization results of block size and fracture development. The simulated damage results, statistical results, are presented according to different slope crest widths and borehole spacings. Figure 3 As shown. Other parameters are basically the same as in Example 1 above.

[0049] Table 1 Slope top width and borehole spacing parameters Numerical simulations with different borehole spacings show that increasing the spacing weakens the superimposed effect of explosive blasting between boreholes, reduces inter-bore cracks, and lowers the degree of rock fragmentation. To further quantitatively analyze the distribution of damaged areas caused by increased borehole spacing, volume distribution statistics were used. With damage D=0.1 as the interval, the volume of damaged units between D=0 and D=1 was statistically analyzed. The focus was on analyzing the proportion of unit volumes with damage values ​​D in the range of 0.2 to 0.8, thus serving as a quantitative basis for the analysis of rock mass block size after blasting. Simultaneously, with the increase of borehole spacing, the proportion of small-damage areas gradually increased, while the proportion of medium-to-high-damage areas gradually decreased. When the borehole spacing gradually increased from 1.6m to 2m, 3m, and 4m, the proportion of small-damage areas gradually increased from approximately 25% to approximately 27%, 30%, and 40%, respectively. This increase generally conforms to a linear law and also matches the actual distribution pattern of blasted block size. Based on the damage volume distribution, different damage states were normalized as particle size distributions to analyze the influence of different borehole spacings on the blast fragment size. The results show that the cumulative undersize curves under different borehole spacings exhibit significant differences. Figure 3It can be seen that when the row spacing is 1.6m and 2m, the curve shape is an inverted S-shape; while when the row spacing increases to 3m and 4m, the curve transforms into an exponential shape in which the growth rate increases with the block size. This morphological change indicates that as the row spacing increases, the superposition effect of blasting energy between boreholes weakens, resulting in a reduction in the size of the effective fracture network and an increase in the proportion of large-sized rock blocks. Specifically, this is manifested in the sharp increase in the slope of the curve in the large-particle-size section, and a significant decrease in the overall specific surface area of ​​the rock mass, which is not conducive to the full contact reaction between the leaching agent and the ore.

[0050] Further analysis using a damage threshold D=0.8 as the boundary of the crushing zone reveals that when the borehole spacing is less than 3m, the cumulative undersize rates of each curve within the corresponding particle size range are relatively close; however, when the spacing reaches 4m, the cumulative undersize rate is significantly lower, indicating a sharp increase in the proportion of large lumps. Therefore, under the ore body conditions described in this embodiment, the borehole spacing should not exceed 3m to achieve effective in-situ blasting permeability enhancement. Furthermore, considering the slope distribution of the curves above the damage threshold D=0.2 (i.e., the fine ore boundary), the fine ore yield is higher and the proportion of undersize lumps in the small particle size range is larger when the spacing is 1.6m and 2m. In contrast, when the spacing is 3m, the cumulative undersize rate curve is more gently and uniformly distributed across all particle size ranges, indicating that the particle size distribution of the blasted rocks is most ideal under this parameter. This effectively suppresses excessive fine ore while avoiding the generation of too many large lumps, thus providing optimal seepage and reaction conditions for the subsequent leaching process.

[0051] Examples 2-3 and Comparative Examples 1-2 Examples 2-3 and Comparative Examples 1-2 respectively provide a process for blasting-enhanced leaching combined with leaching to treat low-grade gold ore. Compared with Example 1, the only difference is the concentration of sodium thiosulfate solution in the gold leaching reagent system, as shown in Table 2. Other experimental parameters and conditions are basically the same as those in Example 1, and will not be repeated here.

[0052] Table 2 Effect of sodium thiosulfate concentration on gold leaching rate Table 2 shows that when the sodium thiosulfate concentration is below 40 g / L, the leaching rate increases significantly with increasing concentration. At a concentration of only 20 g / L, the leaching rate is as low as 5%. Once the concentration reaches 40 g / L, the increase in leaching rate slows down, and the leaching rate stabilizes at 57% within the range of 50–60 g / L. Concentrations exceeding 50 g / L not only fail to significantly improve the recovery rate but also increase reagent costs and economic burden.

[0053] Examples 4-5 and Comparative Examples 3-5 Examples 4-5 and Comparative Examples 3-5 respectively provide a process for blasting-enhanced leaching combined with leaching to treat low-grade gold ore. Compared with Example 1, the only difference is the concentration of N-(γ-glutamyl)ethanolamine solution in the gold leaching reagent system, as shown in Table 3. Other experimental parameters and conditions are basically the same as those in Example 1, and will not be repeated here.

[0054] Table 3 Effect of N-(γ-glutamyl)ethanolamine concentration on gold leaching rate Table 3 shows that the addition and concentration of N-(γ-glutamyl)ethanolamine have a crucial impact on the gold leaching rate of this system: when its concentration is zero, the gold leaching rate is only 12%, indicating that the lack of stabilizing effect of N-(γ-glutamyl)ethanolamine means that the byproducts generated by the reagent system cannot carry out the leaching reaction effectively; as the concentration increases to 10 g / L, the leaching rate significantly increases to 46%, and further increasing the concentration to 15-20 g / L, the leaching rate increases to 51-52%, at which point the system has reached a relatively optimal state of stability and synergistic leaching; when the concentration further increases to 30-40 g / L, the leaching rate remains at around 54%, and the growth tends to plateau. This indicates that the concentration of N-(γ-glutamyl)ethanolamine in the range of 15-30 g / L can sufficiently ensure the stable operation of the system and the efficient leaching of gold, and the concentration exceeding 30 g / L does not bring about a further significant increase in the leaching rate.

[0055] Examples 6-7 and Comparative Examples 6-8 Examples 6-7 and Comparative Examples 6-8 respectively provide a process for blasting-enhanced leaching combined with leaching to treat low-grade gold ore. Compared with Example 1, the only difference is the concentration of sodium tartrate solution in the gold leaching reagent system, as shown in Table 4. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here.

[0056] Table 4. Effect of sodium tartrate concentration on gold leaching rate Table 4 shows that sodium tartrate concentration is one of the core factors determining the efficiency of this gold leaching system. When sodium tartrate is completely absent, the gold leaching rate is only 6%, indicating that it is indispensable for in-situ dissolution, supplying catalytic iron ions, and maintaining the redox cycle. As the sodium tartrate concentration increases to 40 g / L, the leaching rate increases to 38%. When the concentration reaches 50-60 g / L, the leaching rate further increases to 50-52%, indicating that it can provide a sufficient and continuous source of iron ions for the catalytic oxidation reaction of gold. When the sodium tartrate concentration continues to increase to 75-80 g / L, the leaching rate reaches a plateau of approximately 57%, and the growth tends to slow down. This indicates that when the sodium tartrate concentration is in the range of 60-75 g / L, the system can fully exert its functions of iron dissolution, catalysis, and auxiliary chemical permeation; excessive increases do not significantly improve the final leaching index.

[0057] Comparative Examples 9-10 Comparative Examples 9-10 provide a process for blasting-enhanced leaching combined with leaching to treat low-grade gold ore. The only difference from Example 1 is that N-(γ-glutamyl)ethanolamine in the gold leaching reagent system is replaced with L-histidine or glycine, as shown in Table 5. Other experimental parameters and conditions are basically the same as in Example 1, and will not be repeated here.

[0058] Table 5. Effects of different reagent types on gold leaching rate Table 5 shows that the type of leaching agent has a decisive influence on the leaching effect of low-grade gold ore. Under the same blasting-enhanced leaching conditions, Example 1 using N-(γ-glutamyl)ethanolamine achieved a gold leaching rate of 52%; however, when it was replaced with L-histidine (Comparative Example 9) or glycine (Comparative Example 10), the leaching rate dropped sharply to only 7% and 5%, respectively. This indicates that conventional amino acids (L-histidine and glycine) have extremely weak complexing ability for gold in this alkaline leaching system, and cannot effectively destroy the passivation film on the gold ore surface or promote gold dissolution. In contrast, N-(γ-glutamyl)ethanolamine, with its unique molecular structure (possessing both amide and hydroxyl groups), can generate a stronger synergistic complexing effect with oxidants and metal ions in the system, thereby significantly improving the gold leaching efficiency.

[0059] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A process for treating low-grade gold ore by blasting and permeation enhancement combined with leaching, characterized in that, Includes the following steps: S1. Drilling and charging are carried out on the ore body bench, and blasting is carried out using a wide-spacing, low-resistance-line hole layout. The parameters of the wide-spacing, low-resistance-line hole layout include: hole spacing 3~5m, row spacing 1.5~4m, hole inclination angle 50~70°, hole over-depth 0.3~1.0m, and hole diameter 120~160mm. The hole density coefficient m of the blasting is determined by block size analysis through numerical simulation, where m = hole spacing / row spacing. Based on the statistical distribution of damage variables, the damage value D in the ore rock after blasting is kept in the range of 0.2~0.8, forming a blasted ore pile. S2. After adjusting the pH of the gold leaching agent system to alkaline, apply it to the surface of the blasted ore pile in solution form; the gold leaching agent system includes sodium thiosulfate, N-(γ-glutamyl)ethanolamine, and sodium tartrate; S3. Control the spraying intensity of the chemical solution so that the chemical solution seeps into the fracture network formed by the blasting, reacts with the gold minerals, and the seeping precious liquid is collected and sprayed again. S4. After leaching, the tailings are sampled and tested to assess the gold leaching rate.

2. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, The concentration of sodium thiosulfate is 30~50 g / L.

3. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, The concentration of the N-(γ-glutamyl)ethanolamine is 15~30 g / L.

4. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, The concentration of sodium tartrate is 50~75 g / L.

5. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, The pH range for the use of the gold immersion agent system is 8.0~10.

0.

6. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, In step S1, the borehole density coefficient of the wide-spacing, small-resistance-line borehole layout is 1.0~2.

0.

7. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, In step S1, the blasting adopts a micro-delay initiation, with an inter-row delay time of 40~70ms and an inter-hole delay time of 15~30ms.

8. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, In step S3, the spraying intensity of the pharmaceutical solution is 5~15 L / m. 2 •h, the leaching cycle is 60~120 days.

9. The process for treating low-grade gold ore by blasting and enhanced permeability leaching according to claim 1, characterized in that, In step S4, the gold leaching rate η is calculated using the following formula: η= [(m1×β1) - (m2×β2)] / (m1×β1) ×100%; Wherein, β1 is the average grade of the original leached mineral sample, β2 is the grade of the tailings sample, m1 is the total mass of the original leached mineral sample, and m2 is the total mass of the tailings after leaching.

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