Beneficiation method for micro-fine particle cyanidation tailings

Abstract

The invention provides a beneficiation method for micro-fine particle cyanidation tailings. The beneficiation method comprises the following steps that S1, the cyanidation tailings are graded through a hydrocyclone, ore particles with the particle size smaller than 20 microns enter overflow tailings, and ore particles with the particle size larger than 20 microns enter bottom flow of the hydrocyclone; s2, the cyclone underflow ore pulp is ground, the ore pulp ground to the target particle size is fed into a flotation tank, a flotation reagent is added, first-stage flotation is conducted, and flotation concentrate 1 and flotation tailings 1 are obtained; s3, after a collecting agent is added into the flotation tailings 1, the flotation tailings 1 are fed for first-stage scavenging; the method has the beneficial effects that based on the close symbiotic characteristic and the partial oxidation characteristic of gold minerals and sulfide minerals such as pyrite, gangue minerals are efficiently removed through the multi-section size mixing-flotation system, and the precious metal enrichment efficiency is greatly improved. A low-intensity magnetic separation purification process is introduced after flotation of concentrate, magnetite and mechanical scrap iron mingled in the concentrate are effectively separated, and the concentrate quality is further improved.

Description

Technical Field

[0001] The present application belongs to the technical field of mineral processing, and in particular relates to a method for processing minerals of fine-grained cyanide tailings. Background Art

[0002] Au in cyanide tailings is mainly found in pyrite-based sulfide minerals. Due to insufficient exposure of gold wrapped in sulfides or insufficient oxygen during the gold leaching process, the gold grade of cyanide tailings is high and gold is lost in the tailings. Related studies have shown that the gold remaining in cyanide tailings can be recovered and fully utilized through mineral processing enrichment after activation.

[0003] At present, the recovery of Au from cyanide tailings mainly includes acid / alkali leaching, roasting-leaching, chlorination, flotation, etc. Among them, acid / alkali leaching-leaching, roasting-leaching, and chlorination have not been widely used due to the disadvantages of secondary tailings, high production costs, and easy corrosion of equipment. Flotation has the advantages of low production cost and no secondary leaching residue, and has broad application prospects. However, the concentrate selected by flotation contains iron filings, iron oxides, etc., which affect the grade of the concentrate. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] In order to solve the above problems, the present application provides a method for beneficiating fine-grained cyanide tailings, comprising the following steps:

[0006] S1. The cyanide tailings are classified by a hydrocyclone, and the ore particles with a particle size less than 20 μm enter the overflow tailings, and the ore particles larger than 20 μm enter the cyclone underflow;

[0007] S2, grinding the slurry under the hydrocyclone, feeding the slurry after grinding to the target particle size into the flotation tank, adding the flotation agent and performing a flotation step to obtain the flotation concentrate 1 and the flotation tailings 1;

[0008] S3, adding a collector to the flotation tailing 1 and feeding it to the first scavenging to obtain scavenging concentrate 1 and scavenging tailing 1; feeding the flotation concentrate 1 to the first concentration to obtain flotation concentrate 2 and flotation tailing 2, the flotation concentrate 2 is then fed to the second concentration to obtain flotation concentrate 3 and flotation tailing 3, the flotation concentrate 3 is fed to the third concentration to obtain flotation concentrate 4 and flotation tailing 4, the flotation tailing 2 and the scavenging concentrate 1 are fed to the first flotation together, the flotation tailing 3 is fed to the first concentration, and the flotation tailing 4 is fed to the second concentration for another flotation treatment;

[0009] S4, feed the flotation concentrate 4 to weak magnetic roughing to obtain magnetic concentrate 1 and magnetic tailings 1, feed the magnetic concentrate 1 to weak magnetic concentration to obtain magnetic concentrate 2 and magnetic tailings 2, and the magnetic tailings 1 and the magnetic tailings 2 are the final non-magnetic gold ore products.

[0010] Optionally, before the step S1, the cyanide tailings need to be stirred and dispersed, and concentrated sulfuric acid is added until the pH of the slurry is adjusted to 6.5.

[0011] Optionally, in step S2, the target particle size is -325 mesh and the particle size distribution rate reaches more than 90%.

[0012] Optionally, in step S2, when the ore pulp ground to the target is fed into the flotation tank, 100-500 g / t of a regulator, 50-150 g / t of a collector and 40-70 g / t of a frother are fed in sequence.

[0013] Optionally, the adjusting agent includes one or more of sodium hexametaphosphate, water glass, and copper sulfate.

[0014] Optionally, the collector includes one or more of 50-60% diethylamine ethyl xanthate, 20-30% mixed fatty acid soap, and 10-20% sulfonated kerosene.

[0015] Optionally, the bubbling agent includes terpineol.

[0016] Optionally, the magnetic field strength of the weak magnetic roughing and weak magnetic cleaning is 90-120 kA / m, and the feed ore concentration is 8-15 wt%.

[0017] Beneficial Effects

[0018] The beneficiation method of fine-grained cyanide tailings provided in the embodiments of the present invention has the following beneficial effects:

[0019] 1. In view of the close symbiosis and partial oxidation characteristics of gold minerals and sulfide minerals such as pyrite, a multi-stage slurry adjustment-flotation system is used to achieve efficient removal of gangue minerals and greatly improve the enrichment efficiency of precious metals.

[0020] 2. Introduce weak magnetic separation purification process after flotation concentrate to effectively separate magnetite and mechanical iron filings contained in the concentrate, and further improve the quality of the concentrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of the beneficiation method of fine-grained cyanide tailings.

[0022] Figure 2 This is the particle size analysis curve of cyanide tailings. DETAILED DESCRIPTION

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0027] See also Figure 1 As shown, according to an embodiment of the present application, a method for beneficiating fine-grained cyanide tailings is provided, comprising the following steps:

[0028] S1. The cyanide tailings are classified by a hydrocyclone, and the ore particles with a particle size less than 20 μm enter the overflow tailings, and the ore particles larger than 20 μm enter the cyclone underflow;

[0029] Specifically, when the cyanide tailings are added to the mixing barrel for strong stirring and dispersion, and the pH value of the slurry is accurately adjusted to 6.5 by adding concentrated sulfuric acid, it enters the hydrocyclone classification stage. The hydrocyclone uses a centrifugal field to separate particles in the slurry. Its working principle is based on the different combined effects of centrifugal force, centripetal force and fluid resistance on particles of different particle sizes and densities in the rotating flow field. In this process, ore particles with a particle size of less than 20μm are relatively weak in the centrifugal field due to their small mass and cannot overcome the resistance of the fluid. Therefore, they will be discharged from the central overflow pipe of the hydrocyclone along with the water flow to become overflow tailings. This part of the overflow tailings is mainly composed of fine-grained gangue minerals. By separating them in advance, the processing volume of the subsequent grinding process can be effectively reduced, energy consumption and equipment wear can be reduced, and at the same time, these fine-grained gangue minerals can be avoided. Interference with subsequent flotation processes and other processes improves the efficiency and pertinence of the entire mineral processing process. Ore particles with a particle size greater than 20μm are subjected to strong centrifugal force in the centrifugal field due to their large mass. They will be thrown to the wall of the hydrocyclone and spiral downward along the wall, and finally discharged from the underflow outlet to become underflow concentrate. This part of the underflow concentrate is relatively enriched with more useful minerals, especially sulfide minerals that coexist with gold minerals. They then enter the grit grinding process, providing more valuable raw materials for subsequent mineral processing operations.

[0030] Among them, by strictly controlling the feed concentration of the hydrocyclone classification at 30-35%, it can ensure that the slurry forms a stable and efficient flow field in the cyclone, thereby achieving accurate classification of the ore particles.

[0031] The rod mill is used for grinding, and the grinding conditions include a rotation speed of 90-100 rpm, a grinding concentration of 60-70 wt%, and a mill filling rate of 25-35%.

[0032] S2, grinding the slurry under the hydrocyclone, feeding the slurry after grinding to the target particle size into the flotation tank, adding the flotation agent and performing a flotation step to obtain the flotation concentrate 1 and the flotation tailings 1;

[0033] Specifically, after grinding in a rod mill, the cyclone underflow pulp is ground to a target particle size, the target particle size is -325 mesh, and the particle size distribution rate reaches 90%. The ground pulp is fed into a flotation tank, and then 100-500g / t of adjusting agents, such as sodium hexametaphosphate, water glass, copper sulfate, etc., are added in sequence. Sodium hexametaphosphate can effectively disperse the fine particles in the pulp, prevent them from agglomerating, improve the fluidity of the pulp, and create good conditions for the subsequent flotation reagents and mineral particles to work together; water glass can inhibit the flotation of gangue minerals and improve the selectivity of the flotation process; copper sulfate, as an activator, can enhance the activity of the surface of sulfide minerals, making it easier to react with collectors. Then, 50-150g / t of collector is added, and the composite collector is composed of 50-60% diethylamine ethyl xanthate, 20-30% mixed fatty acid soap, 10-20% sulfonated kerosene, etc. Diethylamine ethyl xanthate has a strong ability to capture sulfide minerals and can selectively adsorb on the surface of sulfide minerals to make them hydrophobic. Mixed fatty acid soaps further enhance the selective adsorption of surface oxidized sulfide minerals through molecular synergistic effects with diethylamine ethyl xanthate. Sulfonated kerosene plays a role in diluting and improving the dispersibility of the collector, thereby increasing the efficiency of the collector. Finally, 40-70g / t of frother pine alcohol is added. The pine alcohol can form a stable foam layer on the surface of the pulp, carry the bubbles adsorbed with mineral particles to the surface of the pulp, and realize the flotation separation of minerals.

[0034] During the aeration flotation process, the mineral particles in the pulp undergo selective adsorption and hydrophobic transformation under the action of the flotation reagent. The gold-bearing minerals and sulfide minerals with strong hydrophobicity combine with the bubbles and float to the surface of the pulp to form a foam layer. This part of the foam layer is collected and becomes the flotation concentrate 1, which is enriched with a large amount of precious metals and valuable sulfide minerals. The gangue minerals that fail to effectively combine with the bubbles remain at the bottom of the pulp and become the flotation tailings 1.

[0035] S3, adding a collector to the flotation tailing 1 and feeding it to the first scavenging to obtain scavenging concentrate 1 and scavenging tailing 1; feeding the flotation concentrate 1 to the first concentration to obtain flotation concentrate 2 and flotation tailing 2, the flotation concentrate 2 is then fed to the second concentration to obtain flotation concentrate 3 and flotation tailing 3, the flotation concentrate 3 is fed to the third concentration to obtain flotation concentrate 4 and flotation tailing 4, the flotation tailing 2 and the scavenging concentrate 1 are fed to the first flotation together, the flotation tailing 3 is fed to the first concentration, and the flotation tailing 4 is fed to the second concentration for another flotation treatment;

[0036] Specifically, when the flotation tailings 1 enters a scavenging process, in order to more effectively recover the remaining useful minerals therein, an appropriate amount of collector is added, the amount of which is half of the amount of the collector used in the first flotation process, and the type is the same. In the first scavenging process, the tailings 1 are fully mixed with the collector, and with the help of the stirring and aeration of the flotation equipment, the mineral particles that were not effectively captured react with the collector for adsorption, and the hydrophobicity is enhanced. These hydrophobicized mineral particles combine with bubbles and float to the surface of the slurry to form scavenging concentrate 1, while the materials that fail to float become scavenging tailings 1. A certain amount of useful minerals are enriched in the scavenging concentrate 1, which improves the recovery rate of useful minerals.

[0037] At the same time, flotation concentrate 1 enters the first concentration process. The purpose of the first concentration is to remove the gangue minerals and other impurities contained in the flotation concentrate 1 and improve the purity and grade of the concentrate. After the first concentration, flotation concentrate 2 and flotation tailings 2 are obtained. The grade of flotation concentrate 2 is significantly improved compared with flotation concentrate 1, while flotation tailings 2 still contains a small amount of useful minerals that have not been fully recovered.

[0038] The flotation concentrate 2 then enters the second stage of concentration process to further purify the flotation concentrate 2. Through the second stage of concentration, flotation concentrate 3 and flotation tailings 3 are produced. The grade of flotation concentrate 3 is further improved, and its precious metal content is more enriched, while flotation tailings 3 continue to return to the first stage of concentration process to recycle the useful minerals that may remain therein, making full use of resources and reducing mineral losses.

[0039] The flotation concentrate 3 then enters the three-stage concentration process to ensure that the impurity minerals are removed to the maximum extent and the target minerals are highly enriched. After the three-stage concentration, the flotation concentrate 4 and the flotation tailings 4 are finally obtained. The flotation concentrate 4 reaches a higher grade standard and becomes a high-quality concentrate product that can be further processed and utilized, while the flotation tailings 4 returns to the second-stage concentration process and participates in the flotation process again to achieve full resource recovery.

[0040] The flotation tailings 2 and the scavenging concentrate 1 are returned to the first flotation process together, and are treated again using the conditions of the first flotation process, so that the useful minerals remaining in them have a chance to be collected again. This recycling method fully utilizes the characteristics and advantages of each flotation process to form a closed and efficient mineral processing circulation system. Through continuous cyclic flotation, the recovery rate of useful minerals is improved, the content of useful components in the tailings is reduced, and the efficient recovery of precious metals and useful minerals in the cyanide slag is achieved.

[0041] S4, feed the flotation concentrate 4 to weak magnetic roughing to obtain magnetic concentrate 1 and magnetic tailings 1, feed the magnetic concentrate 1 to weak magnetic concentration to obtain magnetic concentrate 2 and magnetic tailings 2, and the magnetic tailings 1 and the magnetic tailings 2 are the final non-magnetic gold ore products.

[0042] Specifically, the flotation concentrate 4 is sent to the weak magnetic roughing process, the goal of which is to preliminarily separate the magnetic substances contained in the concentrate, such as magnetite and mechanical iron filings. Weak magnetic roughing is carried out under a specific magnetic field environment, and the magnetic field strength is accurately controlled within the range of 90-120kA / m. This magnetic field strength range has been verified by a large number of experiments and practices to ensure good capture of fine magnetic impurities without causing excessive interference to target minerals such as non-magnetic gold-bearing minerals. In the weak magnetic roughing process, the feed slurry concentration is strictly controlled at 8-15wt%. The appropriate slurry concentration can not only ensure that the magnetic particles can be fully separated by the magnetic force in the magnetic field, but also make the slurry have good fluidity, which is easy to operate and separate.

[0043] In the weak magnetic roughing equipment, the magnetic particles of the ore pulp are rapidly adsorbed to the magnetic pole surface of the magnetic separation equipment under the action of the magnetic field. As the equipment operates, these adsorbed magnetic particles are collected to form magnetic separation concentrate 1. The non-magnetic gold-bearing minerals and other target minerals continue to flow with the ore pulp and become magnetic separation tailings 1. Through weak magnetic roughing, the flotation concentrate 4 is initially purified, the content of magnetic impurities therein is reduced, and more favorable conditions are provided for subsequent weak magnetic concentration.

[0044] The magnetic concentrate 1 then enters the weak magnetic concentration process. The purpose of weak magnetic concentration is to re-screen the magnetic concentrate 1 to minimize the loss of non-magnetic useful minerals and improve the recovery rate of the final product. During the weak magnetic concentration process, the magnetic field strength and slurry concentration conditions similar to those of the weak magnetic roughing are still maintained. By applying the magnetic field again, the magnetic impurities that were originally mixed with non-magnetic useful minerals during the weak magnetic roughing process are further captured to form a magnetic concentrate 2. The remaining material after the second screening becomes the magnetic tailings 2, and the magnetic tailings 1 and the magnetic tailings 2 are combined to form the final product of the entire beneficiation process.

[0045] As the final products, magnetic separation tailings 1 and magnetic separation tailings 2 have undergone a series of complex processing processes such as classification, grinding, flotation and weak magnetic separation. Useful components such as gold-bearing minerals have been highly enriched, and interfering substances such as magnetic impurities have been effectively removed, effectively improving the grade of the final products.

[0046] Optionally, before the step S1, the cyanide tailings need to be stirred and dispersed, and concentrated sulfuric acid is added until the pH of the slurry is adjusted to 6.5.

[0047] Optionally, in step S2, the target particle size is -325 mesh and the particle size distribution rate reaches more than 90%.

[0048] Optionally, in step S2, when the ore pulp ground to the target is fed into the flotation tank, 100-500 g / t of a regulator, 50-150 g / t of a collector and 40-70 g / t of a frother are fed in sequence.

[0049] Optionally, the adjusting agent includes one or more of sodium hexametaphosphate, water glass, and copper sulfate.

[0050] Optionally, the collector includes one or more of 50-60% diethylamine ethyl xanthate, 20-30% mixed fatty acid soap, and 10-20% sulfonated kerosene.

[0051] Optionally, the bubbling agent includes terpineol.

[0052] Optionally, the magnetic field strength of the weak magnetic roughing and weak magnetic cleaning is 90-120 kA / m, and the feed ore concentration is 8-15 wt%.

[0053] The present application selects a certain stockpiled cyanide tailings, in which the -325 mesh particle size content in the ore accounts for more than 80%, the main useful minerals are native gold and tellurium ore, and other metal minerals include pyrite, chalcopyrite, galena, sphalerite, limonite, hematite, and a small amount of antimonite and stibnite; the main gangue minerals are quartz, and a small amount of albite, illite, calcite, etc., and Au in the ore mainly exists in the form of native gold, tellurium ore, and tellurium-gold-silver ore. About 90% of Au is present in the form of sulfide-encapsulated gold in pyrite, followed by limonite. The Au grade in the cyanide tailings is 1.15 g / t, and the chemical analysis results of the raw ore are shown in Table 1.

[0054] Table 1 Chemical analysis results of raw ore

[0055]

[0056] Note: Data with * are in g / t, and the rest are in wt%.

[0057] Use a laser particle size analyzer to analyze the particle size of the cyanide tailings after cyanide decomposition and dispersion. The analysis results are shown in Figure 2 .

[0058] About 38.19% of the mineral particles are below 10μm. Combined with the statistical results of particle size analysis, the volume average diameter of the cyanide slag sample is 26.23μm, and the median diameter (D50) is 15.05μm. These results all indicate that the particle size of cyanide tailings is relatively fine, while the suitable flotation particle size of sulfide minerals is generally 10-200μm, and about 80% of pyrite is currently concentrated in 20-60μm. Therefore, during flotation, pre-classification grinding can be considered to reduce mineral muddling.

[0059] Embodiment Conditions Test samples were all made of uniformly mixed cyanide tailings, 4 portions were taken, each with a mass of 1 kg, and were numbered A, B, C, and D respectively.

[0060] Example 1

[0061] The cyanide tailings sample was stirred and dispersed, and then concentrated sulfuric acid was added to adjust the pH value of the pulp to 6.5. Then the hydrocyclone was used for classification, and the feed concentration of the hydrocyclone classification was set to 30%. The cyclone underflow pulp obtained after classification was sent to the rod mill for grinding until the ore particles reached more than 90% of -325 mesh, and then it was added to the flotation tank.

[0062] In the flotation tank, flotation reagents are added in sequence. Among them, the amount of copper sulfate is 100, 200, 400, 600g / t, the amount of water glass is 300g / t, the amount of diethylamine ethyl xanthate is 100g / t, the amount of mixed fatty acid soap is 30g / t, and the amount of pine alcohol is 40g / t. The flotation concentrate 1 and the flotation tailing 1 are obtained by first-stage flotation. The flotation tailing 1 is scavenged by adding a collector to obtain a scavenged concentrate 1 and a scavenged tailing 1, wherein the amount of the collector is half of the amount of the first-stage flotation collector; the flotation concentrate 1 is scavenged by adding a collector to the flotation tailing 1. The first stage of concentration is carried out to obtain flotation concentrate 2 and flotation tailing 2, and the flotation concentrate 2 is fed to the second stage of concentration to obtain flotation concentrate 3 and flotation tailing 3, and then the flotation concentrate 3 is fed to the third stage of concentration to obtain flotation concentrate 4 and flotation tailing 4. In this process, the flotation tailing 2 is mixed with the scavenging concentrate 1 and fed to the first stage of flotation, while the flotation tailing 3 is fed to the first stage of concentration, and the flotation tailing 4 is fed to the second stage of concentration. After the flotation is completed, the foam concentrate of the flotation concentrate 4 is dried, and the grade of Au in each concentrate is analyzed and the recovery rate of Au is calculated. The results show that the Au grades in the concentrates of A, B, C, and D are 9.7g / t, 15.9g / t, 18.3g / t, and 21.9g / t, respectively, and the Au recovery rates are 61.39%, 60.35%, 55.53%, and 52.39%, respectively.

[0063] When the flotation concentrate 4 is subjected to weak magnetic roughing and weak magnetic concentration again, the Au grades in the concentrates A, B, C and D can be increased to 12.3 g / t, 17.8 g / t, 22.4 g / t and 25.1 g / t, respectively, but the Au recovery rate decreases slightly to 60.25%, 58.98%, 55.39% and 50.18%, respectively.

[0064] By comparing the above experimental results, it can be seen that by adding the magnetic separation process after flotation, the Au grade in the concentrate can be improved while ensuring that the recovery rate is not much different.

[0065] Example 2

[0066] The cyanide tailings sample was stirred and dispersed, and then concentrated sulfuric acid was added to adjust the pH value of the pulp to 6.5. Then the hydrocyclone was used for classification, and the feed concentration of the hydrocyclone classification was set to 30%. The cyclone underflow pulp obtained after classification was sent to the rod mill for grinding until the ore particles reached more than 90% of -325 mesh, and then it was added to the flotation tank.

[0067] In the flotation tank, flotation reagents are added in sequence. Among them, the amount of copper sulfate is 200g / t, the amount of water glass is 300g / t, the amount of diethylamine ethyl xanthate is 80, 100, 120, 140g / t respectively, the amount of mixed fatty acid soap is 30g / t, and the amount of pine alcohol is 40g / t. The flotation is carried out in a first stage to obtain flotation concentrate 1 and flotation tailing 1. The flotation tailing 1 is scavenged by adding a collector to obtain scavenged concentrate 1 and scavenged tailing 1, wherein the amount of the collector is half of the amount of the collector used in the first stage of flotation; the flotation concentrate 1 is scavenged by adding a collector to the flotation tailing 1. The first stage of concentration obtains flotation concentrate 2 and flotation tailing 2, and the flotation concentrate 2 is fed to the second stage of concentration to obtain flotation concentrate 3 and flotation tailing 3, and then the flotation concentrate 3 is fed to the third stage of concentration to obtain flotation concentrate 4 and flotation tailing 4. In this process, the flotation tailing 2 is mixed with the scavenging concentrate 1 and fed to the first stage of flotation, while the flotation tailing 3 is fed to the first stage of concentration, and the flotation tailing 4 is fed to the second stage of concentration. After the flotation is completed, the foam concentrate of the flotation concentrate 4 is dried, and the grade of Au in each concentrate is analyzed and the recovery rate of Au is calculated. The results show that the Au grades in the concentrates of A, B, C, and D are 16.2g / t, 15.9g / t, 14.3g / t, and 10.5g / t, respectively, and the gold recovery rates are 55.29%, 60.35%, 66.96%, and 72.56%, respectively.

[0068] When the flotation concentrate 4 is subjected to weak magnetic roughing and weak magnetic concentration again, the Au grades in the concentrates A, B, C and D can be increased to 18.6 g / t, 16.1 g / t, 14.8 g / t and 11.1 g / t, respectively, and the Au recovery rates slightly decrease or remain unchanged, which are 55.08%, 59.02%, 63.25% and 70.99%, respectively.

[0069] By comparing the above experimental results, it can be seen that by adding the magnetic separation process after flotation, the Au grade in the concentrate can be improved while ensuring that the recovery rate is not much different.

[0070] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for beneficiating fine cyanide tailings, characterized in that: The following steps are involved: S1. The cyanide tailings are classified through a hydrocyclone, and the ore particles with a particle size of less than 20 μm enter the overflow tailings, and the ore particles larger than 20 μm enter the cyclone underflow; S2, grinding the slurry under the hydrocyclone, feeding the slurry after grinding to the target particle size into the flotation tank, adding the flotation agent and performing a flotation step to obtain the flotation concentrate 1 and the flotation tailings 1; S3, adding a collector to the flotation tailing 1 and feeding it to the first scavenging to obtain scavenging concentrate 1 and scavenging tailing 1; feeding the flotation concentrate 1 to the first concentration to obtain flotation concentrate 2 and flotation tailing 2, the flotation concentrate 2 is then fed to the second concentration to obtain flotation concentrate 3 and flotation tailing 3, the flotation concentrate 3 is fed to the third concentration to obtain flotation concentrate 4 and flotation tailing 4, the flotation tailing 2 and the scavenging concentrate 1 are fed to the first flotation together, the flotation tailing 3 is fed to the first concentration, and the flotation tailing 4 is fed to the second concentration for another flotation treatment; S4, feed the flotation concentrate 4 to weak magnetic roughing to obtain magnetic concentrate 1 and magnetic tailings 1, feed the magnetic concentrate 1 to weak magnetic concentration to obtain magnetic concentrate 2 and magnetic tailings 2, and the magnetic tailings 1 and the magnetic tailings 2 are the final non-magnetic gold ore products.

2. The method for beneficiating fine cyanide tailings according to claim 1, characterized in that: Before the step S1, the cyanide tailings need to be stirred and dispersed, and concentrated sulfuric acid is added until the pH of the slurry is adjusted to 6.

5.

3. The method for beneficiating fine cyanide tailings according to claim 1, characterized in that: In step S2, the target particle size is -325 mesh and the particle size distribution rate reaches more than 90%.

4. The method for beneficiating fine cyanide tailings according to claim 1, characterized in that: In step S2, when the ore pulp ground to the target is fed into the flotation tank, 100-500 g / t of a regulator, 50-150 g / t of a collector and 40-70 g / t of a frother are sequentially fed.

5. The method for beneficiating fine cyanide tailings according to claim 4, characterized in that: The adjusting agent includes one or more of sodium hexametaphosphate, water glass and copper sulfate.

6. The method for beneficiating fine cyanide tailings according to claim 4, characterized in that: The collector comprises one or more of 50-60% diethylamine ethyl xanthate, 20-30% mixed fatty acid soap, and 10-20% sulfonated kerosene.

7. The method for beneficiating fine cyanide tailings according to claim 4, characterized in that: The bubbling agent includes terpineol.

8. The method for beneficiating fine cyanide tailings according to claim 1, characterized in that: The magnetic field strength of the weak magnetic roughing and weak magnetic concentrating is 90-120 kA / m, and the feed concentration is 8-15 wt%.

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