A method for determining sulfide in flotation tailings based on accurate flocculation of gangue

Abstract

This invention discloses a method for determining sulfides in flotation tailings based on precise gangue flocculation, belonging to the field of process mineralogy analysis technology. First, the tailings sample is slurry-dispersed, and a composite selective flocculant is added. Gradient stirring and turbidity endpoint control are used to selectively flocculate gangue minerals while maintaining sulfide dispersion. Then, a precipitate rich in gangue flocs is obtained through stratified solid-liquid separation. After mixing and sampling, MLA analysis is performed to obtain the relative gangue content in the precipitate. Finally, a dual-error correction model is used to calculate the true sulfide content. This invention achieves precise separation of gangue and sulfides at the source. Combined with error correction, it significantly improves the accuracy of sulfide detection in low-content, fine-particle tailings. The method is simple to operate, highly adaptable, and suitable for batch testing of various sulfide flotation tailings.

Description

Technical Field

[0001] This invention relates to the field of process mineralogy analysis technology, specifically to a method for determining sulfides in flotation tailings based on precise gangue flocculation. Background Technology

[0002] In the flotation process of sulfide ores, fine-grained sulfide ores are difficult to recover effectively due to factors such as electrostatic repulsion between particles, Brownian motion, and differences in surface energy. A considerable amount of sulfide minerals are discharged with the tailings, resulting in the loss of valuable metals. Accurately determining the true content of sulfides in flotation tailings is a crucial prerequisite for evaluating flotation recovery rates, optimizing reagent regimes and process parameters, and achieving comprehensive utilization of tailings resources. It directly relates to the efficient development of mineral resources and the economic benefits of enterprises. Sulfides in flotation tailings are typically present in extremely low concentrations and are extremely fine in particle size, mostly in the submicron to micron range, making effective recovery by flotation almost impossible. Determining the true content of sulfides in such tailings faces not only the dilution effect caused by low concentrations but, more fundamentally, the technical challenges inherent in the fine particle size itself.

[0003] Currently, mineral liberation analysis (MLA) systems have become the mainstream equipment for mineral content determination due to their advantages such as high automation, fast analysis speed, and ability to provide microscopic mineral liberation information, and are widely used in process mineralogy research. However, when applied to flotation tailings samples, the sulfide mineral content is extremely low, typically accounting for only 0.1% to 5% of the total tailings. Diluted by a large amount of gangue minerals (such as quartz, feldspar, and calcite), the electron beam of the MLA is prone to missing or misjudging the already small number of sulfide particles during scanning. More importantly, the sulfide particles in the tailings are mostly in the submicron to micron range, far below the particle size threshold that the MLA electron beam can effectively identify. Even if the scanning window covers the target area, the electron beam struggles to accurately distinguish fine sulfide particles from the background. Furthermore, residual flotation reagents and slime in the tailings further amplify background signal noise, further interfering with the accurate identification and quantification of sulfide particles. When the combined effects of extremely low sulfide content and extremely fine particle size are present, the results of direct MLA measurements often exhibit a systematic bias of tens of percent. This means that the measured values ​​cannot reflect the true amount of sulfide loss, nor can they provide reliable data support for flotation process optimization. Therefore, accurately determining the true content of fine-grained, low-content sulfides in flotation tailings has become a key bottleneck restricting process mineralogical analysis and beneficiation process optimization.

[0004] In view of this, there is an urgent need to develop a determination method that has high selective flocculation capability, accurate error correction mechanism, is easy to operate and highly adaptable, can accurately determine the true content of sulfides in flotation tailings, can effectively avoid the difficulties of direct detection of fine sulfides, and can be compatible with the high throughput and high precision advantages of existing mainstream analytical equipment such as MLA, so as to provide reliable data support for mineral processing optimization and comprehensive utilization of tailings resources. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a method for determining sulfides in flotation tailings based on precise gangue flocculation. The present invention involves dispersing the tailings sample into a slurry, adding a composite selective flocculant, and using gradient stirring and turbidity endpoint control to selectively flocculate gangue minerals while maintaining sulfide dispersion. Then, through stratified solid-liquid separation, a precipitate rich in gangue flocs is obtained. After mixing and sampling, MLA analysis is performed to obtain the relative gangue content in the precipitate. Finally, a dual-error correction model is used to calculate the true sulfide content. This method achieves precise separation of gangue and sulfides at the source, and combined with error correction, significantly improves the accuracy of sulfide detection in low-content, fine-particle tailings. It is simple to operate, highly adaptable, and suitable for batch testing of various sulfide flotation tailings.

[0006] This invention provides a method for determining sulfides in flotation tailings based on precise gangue flocculation, comprising the following steps: S1. Selective flocculation separation: Prepare flotation tailings slurry, add composite selective flocculant to flotation tailings slurry, and selectively flocculate and agglomerate gangue minerals under gradient stirring mode, while keeping sulfide minerals in a dispersed state. S2, Solid-liquid separation and representative sampling: Gravity sedimentation is used to separate the solid and liquid of the flocculated slurry to obtain an upper suspension rich in sulfide particles and a precipitate rich in gangue flocs; then, the precipitate is thoroughly mixed and a portion is taken as a precipitate sample to be tested. S3, Gangue content determination: The sample of the precipitate to be tested is prepared, and the relative content of gangue minerals is determined by a mineral dissociation analysis system; S4, Sulfide content calculation: Based on the total dry weight of the flotation tailings sample, the mass of the precipitate sample to be tested, the relative content of the gangue minerals, and in combination with at least one error correction parameter, the true sulfide content in the flotation tailings sample is calculated.

[0007] As a further improvement of the present invention, in step S4, the error correction parameters include a flocculation efficiency correction coefficient and a system error correction value; wherein, the flocculation efficiency correction coefficient is used to correct the gangue residue deviation caused by incomplete gangue flocculation, and the system error correction value is used to correct the system deviation caused by equipment precision and operational factors.

[0008] As a further improvement of the present invention, in step S4, the formula for calculating the true sulfide content S in the flotation tailings sample is as follows: S = 100% - [(m / G) × P × f] - Δ; In the formula, G is the total dry weight of the flotation tailings sample; m is the mass of the precipitate sample to be tested; P represents the relative content of gangue minerals in the precipitate as determined by a mineral dissociation analysis system; f is the flocculation efficiency correction coefficient, calculated using the formula: f = 1 - (C / G) 脉石总 ), where C is the mass of gangue remaining in the upper suspension, and G 脉石总 C and G represent the theoretical total mass of gangue in the flotation tailings. 脉石总 All values ​​were determined through chemical analysis; the value of f ranged from 0.95 to 0.99. Δ is the systematic error correction value, which is determined by fitting parallel experiments of no less than 5 groups of similar flotation tailings samples. It is the statistical average of the difference between the true value of chemical analysis and the calculated value; the value of Δ ranges from 0.01% to 0.05%.

[0009] As a further improvement of the present invention, in step S1, the composite selective flocculant is a ternary compound system comprising inorganic flocculant components, organic polymeric flocculant components and natural polymeric coagulant components. The inorganic flocculant is polyaluminum chloride, the organic polymer flocculant is anionic polyacrylamide, and the natural polymer coagulant is modified starch; and the mass ratio of polyaluminum chloride, modified starch and anionic polyacrylamide is (1.5~2.5):(2.5~3.5):1.

[0010] As a further improvement of the present invention, in step S1, the gradient stirring mode is specifically set as follows: in the initial stage, stirring is performed at a higher speed to promote full contact between the flocculant and the mineral particles; in the middle stage, stirring is performed at a medium speed to guide the gangue particles to directional flocculation and agglomeration; and in the final stage, stirring is performed at a lower speed to avoid floc breakage; and the stirring intensity of the gradient stirring decreases with time.

[0011] As a further improvement of the present invention, the rotation speed in the initial stage is 600~650 r / min and the stirring time is 4~6 min; the rotation speed in the intermediate stage is 350~450 r / min and the stirring time is 10~15 min; and the rotation speed in the final stage is 200~250 r / min and the stirring time is 4~6 min.

[0012] As a further improvement of the present invention, in step S1, the selective flocculation separation step further includes monitoring the turbidity of the slurry, and when the turbidity is lower than a preset threshold, it is determined to be the flocculation endpoint, wherein the preset threshold is 50 NTU.

[0013] As a further improvement of the present invention, in step S2, the solid-liquid separation step specifically includes: firstly, performing a first stage of rapid gravity sedimentation to separate and remove the upper layer of suspension rich in sulfide particles; then, performing a second stage of static sedimentation and compaction on the bottom sediment to obtain the precipitate.

[0014] As a further improvement of the present invention, the sulfide content in the flotation tailings is 0.1% to 5%, and the particle size of the sulfide minerals is submicron to micron. The gangue minerals in the flotation tailings are a composite of quartz, silicate, and carbonate minerals; and the composition ratio of the composite selective flocculant is adaptively adjusted according to the proportion of components in the gangue minerals.

[0015] As a further improvement of the present invention, before step S1, a sample pretreatment step is also included, specifically: the flotation tailings sample and water are mixed at a solid-liquid mass ratio of 1:2.5 to 1:4, a dispersant is added, and the mixture is stirred at a speed of 300 to 500 r / min for 10 to 15 min to prepare a slurry with uniform particle dispersion; the dispersant is sodium hexametaphosphate or sodium citrate, and the amount added is 0.01% to 0.03% of the dry weight of the flotation tailings sample.

[0016] Beneficial effects: 1. The method provided by this invention significantly improves the accuracy of measurement. Through selective flocculation of gangue, sulfides are transformed from a state of low content and difficulty in direct detection of fine particles into a relatively enriched state after the removal of gangue flocs, thus avoiding the blind spot of MLA in recognizing fine sulfides. Combined with dual error correction, the final measured sulfide content can truly reflect the amount lost during flotation, improving accuracy compared to the traditional direct MLA method.

[0017] 2. The method provided by this invention possesses strong industrial adaptability and ease of operation. It does not rely on ultra-high-speed centrifuges, complex heavy liquids, or advanced online analysis equipment; pretreatment can be completed using only conventional stirring, sedimentation, and filtration equipment. This enables batch and accurate detection of various types of sulfide tailings, improving detection efficiency and industrial adaptability. By using a fixed correction coefficient, batch and rapid detection of the same type of tailings can be performed, greatly improving detection efficiency and making it suitable for daily process monitoring in mineral processing plants. By constructing a highly selective and efficient gangue composite flocculation system, precise separation of gangue and sulfides is achieved from the source, completely avoiding the technical pain points of directly detecting fine-particle, low-content sulfides.

[0018] 3. The method provided by this invention is applicable to a wide range of mineral types. The ratio of the composite flocculant can be adjusted according to the content ratio of gangue types (i.e., the content ratio of quartz, silicate, and carbonate types in the composite mineral), making this method adaptable to the tailings characteristics of different mines and possessing broad application prospects. Through layered flocculation and error correction coefficient design, it solves the technical defects of existing indirect methods, such as incomplete flocculation, unrepresentative sampling, and lack of precise calculation correction. Employing a gradient stirring mode of high speed (dispersive contact) - medium speed (directional flocculation) - low speed (avoiding breakage), and combining it with slurry turbidity (≤50 NTU) as a quantitative indicator for the flocculation endpoint, it solves the problems of uncontrollable and unstable effects in traditional flocculation processes, providing process assurance for repeatable and precise separation.

[0019] 4. The method provided by this invention provides a reliable data foundation for process optimization. The accurate sulfide stream loss data can be directly used to accurately calculate the recovery rate of flotation operations, diagnose the shortcomings in the recovery of fine-grained minerals, and guide the optimization of reagent systems, thereby promoting the efficient utilization of mineral resources.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0021] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0022] Figure 1 This is a schematic flowchart of the method for determining sulfides in flotation tailings based on precise gangue flocculation provided in an embodiment of the present invention. Detailed Implementation

[0023] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0024] 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 invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0025] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0026] 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 the invention. 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.

[0027] In the description of the embodiments of this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0028] In the description of the embodiments of the present invention, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0029] To address the technical challenges of low sulfide content and extremely fine particle size in existing flotation tailings, which lead to blind spots and background noise interference in direct MLA (methyl sulfide) determination, this invention provides a method for determining sulfides in flotation tailings based on precise gangue flocculation. Using a specific ternary composite flocculant (polyaluminum chloride, modified starch, and anionic polyacrylamide), a large amount of gangue minerals in the complex slurry are selectively flocculated into coarse particles, while the target sulfides remain in a fine-particle dispersed state, achieving physical separation of the two at the source. Secondly, a closed-loop stratified separation and representative sampling process is employed. Gradient stirring and turbidity endpoint control ensure the repeatability of the flocculation process. Furthermore, two-step sedimentation and full-volume mixing sampling fundamentally eliminate errors caused by sampling segregation. Finally, a two-parameter error correction model is established, using a flocculation efficiency correction coefficient f (correcting for incomplete physical separation) and a systematic error correction value Δ (correcting for instrument and operational deviations). The true sulfide content is then accurately calculated using a formula.

[0030] Please refer to Figure 1 As shown, this embodiment of the invention provides a method for determining sulfides in flotation tailings based on precise gangue flocculation, comprising the following steps: S0, Sample Pretreatment: Collect flotation tailings samples, mix them thoroughly, send a portion for chemical analysis, and weigh the remaining samples using an electronic balance, recording the total dry weight G of the tailings. Add deionized water at a solid-liquid mass ratio of 1:2.5~1:4, and simultaneously add 0.01%~0.03% dispersant (preferably sodium hexametaphosphate or sodium citrate). Stir at 300~500 r / min for 10~15 min to prepare a slurry with uniform concentration and completely dispersed particles. The addition of dispersant can prevent particle agglomeration and create a uniform reaction environment for subsequent precise flocculation of gangue, reducing flocculation errors from the source.

[0031] S1, Gangue Composite Selective Flocculation: A gangue composite selective flocculant is added to the slurry. This composite flocculant is composed of polyaluminum chloride, modified starch, and anionic PAM in a mass ratio of 2:3:1, and the ratio can be adjusted to accommodate different gangue mineral contents, such as quartz, silicate, and carbonate. This composite flocculant exhibits strong selectivity for major gangue minerals such as quartz, silicates, and carbonates, causing gangue mineral particles to rapidly agglomerate into large flocs with a particle size ≥50μm, while sulfide minerals remain dispersed without significant entrainment. Flocculation is performed using a gradient stirring mode: for the first 5 minutes, high-speed stirring at 600~650r / min breaks up initial particle agglomeration and promotes full contact between the flocculant and gangue minerals; for the middle 10~15 minutes, medium-speed stirring at 350~450r / min guides the gangue particles to directionally flocculate and agglomerate; for the last 5 minutes, low-speed stirring at 200~250r / min prevents floc breakage. The turbidity of the slurry is monitored in real time during the flocculation process, and the flocculation endpoint is determined when the turbidity is ≤50 NTU. The amount of the composite flocculant added is 250~650g per ton of flotation tailings, which can be dynamically adjusted according to the gangue content of the tailings to ensure a balance between flocculation efficiency and selectivity.

[0032] S2, Solid-Liquid Separation and Mixing Sampling: Stop stirring and allow rapid gravity sedimentation for 3-8 minutes to quickly settle the gangue flocs to the bottom of the container. Use a pipette to separate and remove the upper suspension rich in fine sulfide particles. Let the bottom sediment stand for another 15-40 minutes to allow the remaining gangue flocs to settle and compact fully, obtaining a high-purity gangue flocculent precipitate, achieving efficient separation of sulfide minerals and gangue flocculents. After separation, thoroughly mix the sample and use it as the precipitate sample to ensure that the precipitate is fully representative and avoids deviations in gangue content caused by local sampling. Filter and dry the upper suspension for later use.

[0033] S3, Standardized Precipitate Preparation and Precise MLA Determination: The uniformly mixed precipitate is placed in a drying oven and dried at 65-110℃ for 4-9 hours until constant weight is achieved (the difference between two consecutive weighings ≤ 0.002g), and the precipitate mass m is recorded. After drying, the precipitate is ground until it passes through a 75μm standard sieve. A portion is mixed with epoxy resin at a mass ratio of 1:1.2-1:2.5, and then inlaid, sanded stepwise, and polished to prepare a smooth sample slide for MLA analysis. The sample slide is analyzed using an automated mineralogical analysis system using MLA equipment, and the relative content P of gangue minerals is calculated.

[0034] S4, Sulfide content calculation: The calculation formula is: S = 100% - [(m / G) × P × f] - Δ; ① Total proportion of gangue = (m / G) × P × flocculation efficiency correction coefficient f; ② The true sulfide content S = 100% - the percentage of total gangue - the systematic error correction value (Δ); The calculation method for the flocculation efficiency correction coefficient f is: f = 1 - (C / G) 脉石总 C is the mass of gangue remaining in the suspension, and G is the mass of gangue. 脉石总 The theoretical total mass of gangue in the original tailings (all determined by chemical analysis) is given. The value of f ranges from 0.95 to 0.99 and is used to correct for calculation deviations caused by incomplete gangue flocculation and a small amount of residue.

[0035] The systematic error correction value (Δ) is determined based on the difference between the true and calculated chemical analysis values ​​of tailings of the same type. It is obtained through fitting multiple parallel experiments (no fewer than 5 groups), and its value ranges from 0.01% to 0.05%. It is used to correct for the influence of systematic factors such as equipment accuracy and operational errors. The specific process is as follows: Based on the true and calculated chemical analysis values ​​of tailings in the same group, through multiple parallel experiments, Δ1 = true value 1 - calculated value 1, and so on, Δ = (Δ1 + Δ2 + ... + Δ...) n )÷n.

[0036] In this invention, whole-rock chemical multi-element analysis and mineral phase calculation methods are used to send mineral samples to a testing institution and obtain the true value of sulfides based on the test results.

[0037] The systematic error correction value Δ represents the systematic error of the measurement method under specific instrument and test conditions. Its value depends on systematic factors such as instrument status and test conditions, rather than on the gangue type. Δ is determined by taking the arithmetic mean of multiple parallel experiments using the true chemical analysis values ​​and XRF calculated values ​​of the same tailings group.

[0038] S5. When conducting batch testing of the same type of flotation tailings in the future, repeat the above steps S1 to S3. There is no need to establish additional correction coefficients. Just substitute them into the formula in step S4 to calculate and quickly obtain the true sulfide content.

[0039] Example 1 Embodiment 1 of the present invention provides a method for determining sulfides in flotation tailings based on precise gangue flocculation, comprising the following steps: S0, Sample Pretreatment Collect 1000g of gold ore flotation tailings sample, mix thoroughly in a stirring container, and send 100g of the sample to the laboratory for chemical analysis (for subsequent G...). 脉石总 (Calculation); The remaining 900g sample was accurately weighed using an electronic balance and dried in a drying oven at 80℃ until constant weight. The total dry weight of the tailings was recorded as G=886g. The dried 886g sample was placed in a mixing tank, and 2658g of deionized water was added at a solid-liquid mass ratio of 1:3. At the same time, 0.02% of the total mass of the slurry dispersant (sodium hexametaphosphate) was added. The mixture was stirred at 400r / min for 12min to prepare a slurry with uniform concentration and completely dispersed particles, avoiding particle agglomeration that would affect the subsequent flocculation effect.

[0040] S1, gangue composite selective flocculation A gangue composite selective flocculant (composed of polyaluminum chloride, modified starch, and anionic PAM in a mass ratio of 2:3:1) was added to the above slurry at a rate of 320g per ton of flotation tailings. The actual amount added in this case was approximately 886g ÷ 1000 × 320g ≈ 283.5g. Flocculation was carried out using a gradient stirring mode: for the first 5 minutes, high-speed stirring at 620 rpm was used to break up initial particle agglomeration and promote full contact between the flocculant and gangue; for the middle 12 minutes, medium-speed stirring at 400 rpm was used to guide the gangue particles to directional flocculation and agglomeration; and for the last 5 minutes, low-speed stirring at 220 rpm was used to prevent the already formed flocs from breaking down. The turbidity of the slurry was monitored in real time during the flocculation process, and the flocculation endpoint was determined when the turbidity dropped to 45 NTU.

[0041] S2, Layered Closed-Loop Solid-Liquid Separation and Mixed Sampling After the flocculation reaction was completed, stirring was stopped, and the mixture was allowed to settle rapidly by gravity for 5 minutes to reach the bottom of the mixing tank. The upper suspension, rich in fine sulfide particles, was then slowly separated and removed using a pipette. The bottom sediment was allowed to stand for another 25 minutes to allow the remaining gangue flocs to settle and compact fully, resulting in a high-purity gangue flocculent precipitate, achieving efficient separation of sulfide minerals and gangue flocculents. After separation, the bottom gangue flocculent precipitate was thoroughly mixed and used as a sample for testing. The upper suspension was filtered through quantitative filter paper, dried at 80°C to constant weight, and then used for subsequent calculation of the residual gangue mass C.

[0042] S3, Standardized Sample Preparation of Precipitates and Precise MLA Measurement The uniformly mixed precipitate was placed in a drying oven and dried at 80℃ for 6 hours until constant weight was achieved (the difference between two consecutive weighings was 0.0013g), and the precipitate mass was recorded as m=868.5g. After drying, the precipitate was ground until it completely passed through a 75μm standard sieve. A portion of the ground sample was mixed with epoxy resin at a mass ratio of 1:1.5, and then inlaid, sanded stepwise, and polished to prepare a smooth, scratch-free MLA analysis sample slide. The sample slide was analyzed using an MLA instrument with an automated mineralogical analysis system, and the relative content of gangue minerals was determined to be P=99.5%.

[0043] S4, Sulfide Content Calculation ① Basic data for calculation: The theoretical total mass G of gangue in the original tailings was determined through chemical analysis. 脉石总 =G×relative gangue content=886g×99.6%≈882.46g; the total mass of solids in the upper suspension after drying is 10.2g, and its relative gangue content is 96.1%. Therefore, the mass of gangue remaining in the suspension is C=10.2g×96.1%≈9.80g.

[0044] ② Calculate the flocculation efficiency correction factor f: f = 1 - (C / G) 脉石总 =1-(9.80 / 882.46)≈0.989, which is within a reasonable range of 0.95~0.99.

[0045] ③ Calculate the percentage of total gangue: The percentage of total gangue is calculated as follows: (m / G)×P×f = (868.5 / 886)×99.5%×0.989≈97.82%.

[0046] ④ Determine the systematic error correction value Δ: Obtained through fitting of 6 sets of parallel experiments, Δ = 0.03%, which falls within a reasonable range of 0.01% to 0.05%. This value is determined based on the true and calculated chemical analysis values ​​of the tailings from the same group. The specific calculation results are as follows, obtained through multiple parallel experiments: Δ1 = 96.72% - 96.702%; Δ2 = 96.72% - 96.697%; Δ3 = 96.72% - 96.694%; Δ4 = 96.72% - 96.689%; Δ5 = 96.72% - 96.685%; Δ6 = 96.72% - 96.681%; Δ=(0.018%+0.023%+0.026%+0.031%+0.035%+0.039%)÷6=0.03%.

[0047] ⑤ Calculate the actual sulfide content: S = 100% - 97.82% - 0.03% = 2.15%.

[0048] S5. When conducting batch testing of flotation tailings of this type of gold ore in the future, repeat the above steps S1 to S3. There is no need to establish additional correction coefficients. Simply substitute the values ​​into the formula of step S4 to calculate the true sulfide content quickly.

[0049] In summary, this invention discloses a method for determining sulfides in flotation tailings based on precise gangue flocculation, belonging to the field of process mineralogy analysis technology. Addressing the technical problem of blind spots and background noise interference in direct MLA determination due to extremely low sulfide content and fine particle size in flotation tailings, this invention proposes an indirect determination method. Specifically, it includes: first, dispersing the tailings sample into a slurry, adding a composite selective flocculant, and using gradient stirring and turbidity endpoint control to selectively flocculate gangue minerals while maintaining sulfide dispersion; then, obtaining a precipitate rich in gangue flocs through layered solid-liquid separation, mixing and sampling, and performing MLA determination to obtain the relative gangue content in the precipitate; finally, calculating the true sulfide content using a dual-error correction model. This invention achieves precise separation of gangue and sulfides at the source, and combined with error correction, significantly improves the accuracy of sulfide detection in low-content, fine-particle tailings. It is simple to operate, highly adaptable, and suitable for batch detection of various sulfide ore flotation tailings.

[0050] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. 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 the present invention, are also included within the scope of the present invention.

Claims

1. A method for determining sulfides in flotation tailings based on precise gangue flocculation, characterized in that, Includes the following steps: S1. Selective flocculation separation: Prepare flotation tailings slurry, add composite selective flocculant to flotation tailings slurry, and selectively flocculate and agglomerate gangue minerals under gradient stirring mode, while keeping sulfide minerals in a dispersed state. S2, Solid-liquid separation and representative sampling: Gravity sedimentation is used to separate the solid and liquid of the flocculated slurry to obtain an upper suspension rich in sulfide particles and a precipitate rich in gangue flocs; then, the precipitate is thoroughly mixed and a portion is taken as a precipitate sample to be tested. S3, Gangue content determination: The sample of the precipitate to be tested is prepared, and the relative content of gangue minerals is determined by a mineral dissociation analysis system; S4, Sulfide content calculation: Based on the total dry weight of the flotation tailings sample, the mass of the precipitate sample to be tested, the relative content of the gangue minerals, and combined with the flocculation efficiency correction coefficient and the system error correction value, the true sulfide content in the flotation tailings sample is calculated. The formula for calculating the true sulfide content S in the flotation tailings sample is as follows: S = 100% - [(m / G) × P × f] - Δ; In the formula, G is the total dry weight of the flotation tailings sample; m is the mass of the precipitate sample to be tested; P represents the relative content of gangue minerals in the precipitate as determined by a mineral dissociation analysis system; f is the flocculation efficiency correction coefficient; Δ is the system error correction value.

2. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, The flocculation efficiency correction coefficient f is used to correct for the residual gangue deviation caused by incomplete gangue flocculation, and the calculation formula is: f = 1-(C / G 脉石总 ), where C is the mass of gangue remaining in the upper suspension, and G 脉石总 C and G represent the theoretical total mass of gangue in the flotation tailings. 脉石总 All values ​​were determined through chemical analysis; the value of f ranged from 0.95 to 0.

99.

3. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 2, characterized in that, The system error correction value Δ is used to correct system deviations caused by equipment accuracy and operational factors. It is determined by fitting multiple sets of parallel experiments of the same type of flotation tailings samples and is the statistical average of the difference between the true value of chemical analysis and the calculated value. The value of Δ ranges from 0.01% to 0.05%.

4. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, In step S1, the composite selective flocculant is a ternary compound system comprising inorganic flocculant components, organic polymeric flocculant components, and natural polymeric coagulant aid components. The inorganic flocculant is polyaluminum chloride, the organic polymer flocculant is anionic polyacrylamide, and the natural polymer coagulant is modified starch; and the mass ratio of polyaluminum chloride, modified starch and anionic polyacrylamide is (1.5~2.5):(2.5~3.5):

1.

5. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, In step S1, the gradient stirring mode is specifically set as follows: in the initial stage, stirring is performed at a high speed to promote full contact between the flocculant and the mineral particles; in the middle stage, stirring is performed at a medium speed to guide the gangue particles to directional flocculation and agglomeration; and in the final stage, stirring is performed at a low speed to avoid floc breakage. Furthermore, the stirring intensity of the gradient stirring decreases over time.

6. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 5, characterized in that, The initial stage has a rotation speed of 600-650 r / min and a stirring time of 4-6 min; the intermediate stage has a rotation speed of 350-450 r / min and a stirring time of 10-15 min; and the final stage has a rotation speed of 200-250 r / min and a stirring time of 4-6 min.

7. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, In step S1, the selective flocculation separation step further includes monitoring the turbidity of the slurry. When the turbidity is lower than a preset threshold, it is determined to be the flocculation endpoint. The preset threshold is 50 NTU.

8. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, In step S2, the solid-liquid separation step specifically includes: firstly, performing a first stage of rapid gravity sedimentation to separate and remove the upper layer of suspension rich in sulfide particles; then, performing a second stage of static sedimentation and compaction on the bottom sediment to obtain the precipitate.

9. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, Before step S1, a sample pretreatment step is also included, specifically: the flotation tailings sample is mixed with water at a solid-liquid mass ratio of 1:2.5 to 1:4, a dispersant is added, and the mixture is stirred at a speed of 300 to 500 r / min for 10 to 15 min to prepare a slurry with uniform particle dispersion; the dispersant is sodium hexametaphosphate or sodium citrate, and the amount added is 0.01% to 0.03% of the dry weight of the flotation tailings sample.

10. The method for determining sulfides in flotation tailings based on precise gangue flocculation according to claim 1, characterized in that, The sulfide content in the flotation tailings is 0.1% to 5%, and the particle size of the sulfide minerals is submicron to micron. The gangue minerals in the flotation tailings are a composite of quartz, silicate, and carbonate minerals; and the composition ratio of the composite selective flocculant is adaptively adjusted according to the proportion of components in the gangue minerals.

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