A copper-sulfur flotation separation method based on coarse-grained pyrite carrier physical barrier strengthening

Abstract

This invention belongs to the field of mineral processing technology and discloses a copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite as a carrier. Addressing the problems of severe mechanical entrainment of fine-grained pyrite and kinetic lag in lime inhibition during copper-sulfur separation, this invention utilizes coarse-grained, high-density, hydrophilic pyrite particles obtained from copper-sulfur separation tailings or sulfur concentrate as a carrier. These particles are then enhanced with lime slurry to form a hydrophilic passivation film on their surface. This carrier is then added to the roughing stage of copper-sulfur separation, forming a stable physical barrier layer at the bottom of the froth zone. Subsequently, copper concentrate is obtained through roughing, cleaning, and scavenging, while the carrier is recycled along with the tailings into the sulfur flotation system as sulfur concentrate. This invention intercepts the mechanical entrainment of fine-grained pyrite through steric hindrance and gravity settling effects, compensating for the shortcomings of lime chemical inhibition, significantly reducing the sulfur content of copper concentrate, and improving copper recovery. Furthermore, the carrier is sourced internally and does not require external purchase, resulting in low cost and a simple process.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a copper-sulfur flotation separation method based on physical barrier enhancement of coarse-grained pyrite carrier. Background Technology

[0002] In copper-sulfur ores, chalcopyrite and pyrite often occur in dense coexistence. Their surface physicochemical properties are similar, and their flotation behaviors tend to be similar. In particular, pyrite is easily activated by copper ions in the pulp, acquiring floatability similar to chalcopyrite, making separation difficult. Industrially, a "high alkali + lime" process is commonly used. This involves adding a large amount of lime to raise the pulp pH to above 11, forming a hydrophilic calcium film on the pyrite surface to inhibit its flotation. Simultaneously, xanthate collectors are used to float chalcopyrite.

[0003] However, this traditional process has the following inherent defects: (1) The lime inhibition kinetics are lagging and cannot cover the new cleavage surface in time: During the grinding and slurry preparation process, pyrite is constantly exposed to fresh surfaces, while lime needs a long reaction time (usually 10 to 30 minutes) to form an effective inhibition film on the mineral surface. During this period, the newly exposed pyrite surface is easily activated by copper ions dissolved in the slurry, which leads to a decrease in the lime inhibition effect. Although excess lime (pH>12) can be used in industry to make up for this, excess lime will deteriorate the floatability of chalcopyrite, increase the difficulty of tailings treatment, and aggravate pipe scaling; (2) The in-situ activation of pyrite by copper ions is difficult to reverse: Cu released by chalcopyrite during the grinding and slurry preparation process 2+ It is quickly adsorbed on the surface of pyrite and a copper-rich sulfide layer is generated through surface replacement or electrochemical deposition, making the surface of pyrite extremely easy to react with xanthate. Even under high alkaline conditions, the activated pyrite is still difficult to be completely suppressed by lime, resulting in some pyrite floating into the copper concentrate, causing the sulfur content of the copper concentrate to exceed the standard; (3) The mechanical entrainment of fine pyrite is serious: under high alkaline conditions, the viscosity of the slurry increases, the stability of the foam layer is enhanced, and the drainage speed is slowed down. A large amount of fine pyrite (especially -20 μm particles) is carried into the foam concentrate by the mechanical water flow of the rising bubble group. This non-selective entrainment cannot be eliminated by increasing the amount of lime, but is aggravated by the increase of slurry viscosity.

[0004] To address the aforementioned problems, researchers have explored various improvement methods. For example, they have used reducing agents such as sulfites to pre-reduce the Cu in the slurry. 2+ To reduce the activation of pyrite, some researchers have suggested alternative methods: reducing agents can be used to weaken the activation of pyrite; alternatively, organic inhibitors (such as sodium humate or lignin sulfonate) can be used to replace some of the lime, achieving selective inhibition under low-alkali conditions; some studies have also used combined inhibitors (such as sulfite + lime) to enhance the inhibition effect. However, these methods still have limitations: the reducing agent cannot completely remove Cu adsorbed on the surface of pyrite. 2+Organic inhibitors have large molecular weights and slow diffusion, making it difficult to complete adsorption before new cleavage surfaces are activated. Although combined inhibitors have a certain synergistic effect, they involve many types of agents and large amounts, and fail to solve the problem of mechanical entrainment of fine particles.

[0005] In recent years, some studies have begun to focus on physical intervention methods, such as enhancing foam drainage and adding flushing water. However, these methods have limited effectiveness in inhibiting the entrainment of fine-grained pyrite, and are difficult to modify in engineering. Therefore, there is an urgent need to develop a new method for copper-sulfur separation that does not rely on excessive lime, can physically block the mechanical entrainment of fine-grained pyrite, and can overcome the interference of copper ion activation. Summary of the Invention

[0006] To address the technical problems in existing copper-sulfur separation processes, such as the inability to promptly cover new cleavage surfaces of pyrite due to lime suppression kinetic lag, the irreversible in-situ activation of pyrite by copper ions, and severe mechanical entrainment of fine-grained pyrite, this invention aims to provide a copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite as a carrier. This invention obtains coarse-grained pyrite from within the copper-sulfur separation process and subjects it to lime-enhanced suppression, forming a stable physical barrier layer at the bottom of the flotation froth zone. Utilizing the screening and blocking effects of coarse, high-density, hydrophilic particles, the non-selective entrainment of fine-grained pyrite is effectively reduced, thereby achieving efficient copper-sulfur separation with lower lime consumption.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite support includes the following steps: (1) Carrier acquisition: coarse pyrite is separated from the tailings or sulfur concentrate produced by copper-sulfur separation operation and used as a physical barrier carrier; (2) Carrier-enhanced inhibition treatment: The coarse pyrite obtained in step (1) is made into coarse pyrite slurry, lime slurry is added, and the pH value of the slurry is adjusted to 11.0~12.0 under stirring conditions to generate a hydrophilic passivation film on the surface of the carrier, and the coarse pyrite carrier is enhanced and inhibited. (3) Constructing a physical barrier layer: The coarse pyrite carrier obtained in step (2) is added to the copper-sulfur separation roughing section so that the coarse pyrite carrier forms a stable physical barrier layer at the bottom of the flotation froth zone. (4) Copper-sulfur flotation separation: The copper-sulfur mixed concentrate is slurry prepared and sent to the copper-sulfur separation roughing section. Lime is added to adjust the pH value of the slurry to 9.0~11.0, and then copper collector and frother are added for flotation separation to obtain copper concentrate.

[0008] Preferably, in step (1), the separation method is hierarchical or reselection.

[0009] As a further preferred option, in step (1), when the separation method is grading, the grading is hydrocyclone grading or screening, and when the separation method is gravity separation, the equipment used for gravity separation is a shaking table, spiral chute or centrifugal concentrator.

[0010] Preferably, in step (1), the coarse pyrite has a particle size of 0.1~0.3 mm.

[0011] Preferably, in step (2), the concentration of the coarse pyrite slurry is consistent with the concentration of the slurry in the copper-sulfur separation roughing section, and the concentration of the slurry in the copper-sulfur separation roughing section is 25%~45%.

[0012] Preferably, in step (2), the stirring time is 5 to 15 minutes.

[0013] Preferably, in step (3), based on the solid mass of the slurry in the roughing stage of copper-sulfur separation, the amount of coarse pyrite carrier added is 5%~20%, and the addition location is the bottom of the flotation cell in the roughing stage of copper-sulfur separation or at the slurry inlet; the residence time of the coarse pyrite carrier in the roughing flotation cell is the same as the flotation operation time, and no special carrier circulation loop is provided. Preferably, in step (4), the copper collector is at least one of ethyl thiocyanate (Z-200), sodium ethyl xanthate (ethyl xanthate), and sodium butyl xanthate (butyl xanthate); the foaming agent is methyl isobutyl methanol (MIBC) or pine oil.

[0014] Preferably, in step (4), the amount of copper collector added is 20~200 g / t based on the dry weight of copper-sulfur mixed concentrate, and the amount of foaming agent added is 5~30 g / t.

[0015] As a preferred option, in step (4), the flotation separation includes roughing operation, cleaning operation and scavenging operation in sequence; the roughing operation is carried out once, the cleaning operation is carried out 2 to 4 times, and lime is added for each cleaning operation; the scavenging operation is carried out 2 to 4 times, and copper collector and frother are added for each scavenging operation; the middlings produced by scavenging are returned to the copper-sulfur separation roughing operation section, and the tailings are used as sulfur concentrate or sent to the sulfur flotation system.

[0016] As a further optimization, in step (4), the amount of lime added in a single operation of the fine selection operation is 25% to 50% of the amount of lime added in the rough selection operation; the amount of copper collector added in a single operation of the scavenging operation is 25% to 50% of the amount of copper collector added in the rough selection operation; and the amount of frother added in a single operation of the scavenging operation is 25% to 50% of the amount of frother added in the rough selection operation.

[0017] Preferably, in the method of the present invention, after the flotation separation is completed, the coarse pyrite carrier is incorporated into the sulfur concentrate along with the tailings or enters the sulfur flotation system, so as to realize the closed-loop recovery of the coarse pyrite carrier as a sulfur concentrate product; wherein, after the coarse pyrite carrier enters the sulfur flotation system with the tailings, it can obtain sulfur concentrate through one or more flotations, and the coarse pyrite carrier itself becomes part of the sulfur concentrate, without the need to be separated from the tailings separately.

[0018] The method described in this invention is applicable to the copper-sulfur reseparation operation of copper-sulfur mixed concentrate.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention introduces physical barrier technology for coarse-grained pyrite carriers into the copper-sulfur flotation separation process for the first time. By obtaining coarse-grained pyrite from within the process and inhibiting it with lime, a stable physical barrier layer is constructed at the bottom of the flotation froth zone, fundamentally changing the traditional technical path of "high alkali + lime" that relies solely on chemical inhibition. The mechanism is that the bottom of the froth zone is the key area where fine-grained pyrite is mechanically entrained. Traditional methods attempt to inhibit its flotation by increasing the viscosity of the slurry and covering it with a calcium film, but cannot effectively intercept the pyrite that has been mechanically entrained by the bubbles. Fine particles; however, the coarse-grained hydrophilic pyrite barrier layer constructed in this invention utilizes the heterogeneous coagulation effect and steric hindrance effect of particles in the bubble swarm to cause local eddy dissipation when rising bubbles pass through the barrier layer, reducing the velocity of the entrained water flow. The fine-grained pyrite loses its upward momentum and settles back into the slurry phase. This mechanism fundamentally cuts off the transmission path of mechanical entrainment, solving long-standing technical problems in traditional processes such as the inability to cover new cleavage surfaces in time due to the kinetic lag of lime inhibition, the deterioration of chalcopyrite floatability due to excessive lime, and pipe scaling.

[0020] (2) In this invention, the separated coarse-grained pyrite is mixed with lime slurry through a carrier-enhanced inhibition step and reacted under pH 11.0~12.0 conditions to generate a complete hydrophilic passivation film on the carrier surface. From the perspective of interfacial chemistry, this treatment shifts the surface potential of the carrier in the negative direction, enhancing the electrostatic repulsion of the anion collector. At the same time, calcium ions chemically adsorb onto the iron sites on the pyrite surface to form Fe(OH)2-Ca. 2+ The Ca(OH)₂ multilayer composite film brings the wetting contact angle of the carrier surface close to 0. Compared with the incomplete passivation film on the pyrite surface in traditional processes, which is easily activated by copper ions, the carrier surface of this invention achieves a thermodynamically stable, highly hydrophilic state, even at high Cu concentrations. 2+ In its presence, copper displacement adsorption is difficult to occur on the carrier surface, thus overcoming the defect that copper ions cannot reverse the in-situ activation of pyrite.

[0021] (3) The coarse pyrite carrier of the present invention is derived from the process, and is obtained directly from the tailings or sulfur concentrate of the copper-sulfur separation operation through classification or gravity separation. It does not require external purchase or additional preparation, and the cost is extremely low. More importantly, the pyrite derived from the tailings has undergone a complete copper-sulfur separation cycle, and its surface mineralogical characteristics are highly matched with the slurry environment of this operation, avoiding the problem of uncontrollable surface state caused by incompatibility between exogenous carriers and the system.

[0022] (4) In the carrier addition and physical barrier layer construction steps of the present invention, the carrier is added at the bottom of the roughing flotation cell or at the pulp inlet, and the addition amount is 5% to 20% of the solid mass of the pulp. No dedicated carrier circulation loop is provided. This design fully utilizes the high density (approximately 5.0 g / cm³) of coarse-grained pyrite. 3 ) and gangue minerals (approximately 2.6 g / cm³) 3 The density difference between the particles causes the carrier to form a gravity-driven dynamic equilibrium layer in the flotation cell. The settling velocity of the particles in the flotation cell follows Stokes' law. The final settling velocity of coarse pyrite is much greater than the apparent velocity of the rising bubbles, so it can be stably retained at the bottom of the froth zone. When fine pyrite rises to this area with the bubble group, it collides with the coarse carrier, adheres to it, and falls off in a cycle, and is eventually "washed" back into the slurry phase. This achieves selective separation based on the difference in particle dynamics without any modification to the existing flotation equipment.

[0023] (5) The copper-sulfur flotation separation step of the present invention can achieve efficient separation under conventional lime slurry conditioning (pH 9.0~11.0) and collector flotation conditions; since the physical barrier layer has undertaken the main task of intercepting fine pyrite particles, the amount of lime used can be greatly reduced (compared with the traditional process pH>12); from the perspective of solution chemistry, the lower pH range allows the Ca in the slurry to be reduced. 2+ The lower concentration avoids the formation of an excessively thick Ca(OH)2 precipitate film on the surface of chalcopyrite under high calcium conditions, thereby reducing the non-inhibitory loss of copper minerals. At the same time, the lower slurry viscosity is conducive to bubble mineralization and foam drainage, further reducing the mechanical entrainment of gangue.

[0024] (6) The carrier destination treatment step of the present invention: the coarse pyrite carrier enters the subsequent sulfur flotation operation with the tailings and is recovered as sulfur concentrate product; from the perspective of process mineralogy, the carrier has completed its blocking mission in the copper-sulfur separation operation. Although its surface is passivated by lime, after entering the sulfur flotation system, under the action of activators such as sulfuric acid or copper sulfate, the iron sites on the surface are re-exposed and the floatability is restored; since the carrier itself is pyrite, and the copper-sulfur separation tailings are the raw materials for the sulfur flotation operation, the carrier does not need to be separated from the tailings and can naturally enter the sulfur concentrate product, realizing zero-loss recovery of the carrier and closed-loop circulation within the process, avoiding interference of exogenous additives to the subsequent process.

[0025] (7) This invention is applicable to the copper-sulfur reseparation operation of copper-sulfur mixed concentrate. For copper-sulfur mixed concentrate that has undergone mixed flotation and regrinding, the pyrite particles are generally fine and are located in the transition flow zone or even turbulent zone in the Stokes settling formula. The gravity settling efficiency drops sharply and the mechanical entrainment problem is particularly prominent. Traditional chemical inhibition methods have limited effect on the entrainment control of such fine pyrite particles. However, this invention intervenes in the entrainment process at the scale of bubble-particle interaction by using the shearing and turbulence effect of the physical barrier layer on the bubble group. This achieves a synergistic solution to the binary separation problem of "chemical inhibition-physical entrainment" in the fine particle flotation system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process of the copper-sulfur flotation separation method based on physical barrier enhancement of coarse-grained pyrite carrier according to the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In each embodiment of the present invention, the amount of lime, copper collector and frother added to the roughing operation section is calculated based on the mass of the dry copper-sulfur mixed concentrate entering the copper-sulfur separation roughing flotation cell.

[0029] Example 1 This embodiment provides a copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite support, comprising the following steps: (1) Carrier acquisition: A copper-sulfur mixed concentrate (copper grade 5.2%, sulfur grade 42.5%) was used as the feed material for copper-sulfur flotation separation. From the tailings produced by the copper-sulfur mixed concentrate through copper-sulfur flotation separation, coarse pyrite with a particle size of 0.1~0.3 mm was separated by hydrocyclone classification and used as a physical barrier carrier.

[0030] (2) Carrier strengthening and inhibition treatment: The coarse pyrite separated in step (1) is made into coarse pyrite slurry, lime slurry is added, the concentration of coarse pyrite slurry is kept consistent with the concentration of roughing slurry (both are 35%), stirred for 10 min, and the pH of slurry is adjusted to 11.5 so that a hydrophilic passivation film is generated on the surface of the carrier, and the coarse pyrite carrier with strengthening and inhibition is obtained.

[0031] (3) Construction of physical barrier layer: The coarse pyrite carrier obtained in step (2) is added to the roughing flotation cell. The addition position is at the bottom of the roughing flotation cell, and the addition amount is 12% of the solid mass of the pulp in the roughing flotation cell. The coarse pyrite carrier forms a stable physical barrier layer at the bottom of the flotation froth zone. The residence time of the coarse pyrite carrier in the roughing flotation cell is the same as the flotation operation time, and no special carrier circulation loop is set up.

[0032] (4) Copper-sulfur flotation separation: Lime (addition amount of 1000 g / t) is added to the flotation system to adjust the pH of the pulp to 10.0, and then copper collector Z-200 (40 g / t) and frother MIBC (15 g / t) are added. Copper concentrate is obtained through one roughing operation, three cleaning operations, and two scavenging operations. Lime is added for each cleaning operation, and the amount added at one time is 1 / 3 of the amount of lime used in the roughing operation (about 333 g / t). Copper collector (Z-200, one-time addition amount of about 13.33 g / t) and frother (MIBC, one-time addition amount of about 5 g / t) are added for each scavenging operation. The ore from the scavenging operation is returned to the roughing operation section in sequence, and the tailings are used as sulfur concentrate to enter the sulfur flotation system.

[0033] (5) Closed-circuit recovery of carrier: After flotation, the coarse pyrite carrier enters the subsequent sulfur flotation system with the tailings and is recovered as sulfur concentrate product. The carrier itself becomes part of the sulfur concentrate and does not need to be separated from the tailings.

[0034] The flotation effects of Example 1 and Comparative Examples 1-5 are summarized in Tables 1-2. The main flotation indicators are shown in Tables 1-2. As can be seen from the tables, Example 1 obtained coarse-grained pyrite with a particle size of 0.1-0.3 mm from copper-sulfur separation tailings. After lime strengthening and inhibition (pH 11.5, stirring for 10 min), it was added to the roughing operation at a dosage of 12%, and flotation was carried out under roughing conditions at pH 10.0. Table 2 shows that the copper grade of the copper concentrate product obtained in Example 1 was 20.21%, the copper recovery rate was 88.62%, and the sulfur content was 28.30%. This is because the surface of the coarse-grained pyrite carrier is strongly hydrophilic after sufficient lime passivation, relying on its high density (approximately 5.0 g / cm³) in the flotation cell. 3 The pyrite settles and remains at the bottom of the foam zone, forming a stable physical barrier layer. When the rising bubbles carrying fine pyrite particles pass through this barrier layer, the coarse-grained carrier effectively intercepts mechanical entrainment through spatial steric hindrance and local eddy current dissipation. At the same time, the passivation film ensures that the carrier itself does not adsorb the collector or float, thus achieving efficient separation of copper minerals and pyrite.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that the coarse pyrite carrier separated in step (1) has a particle size of 0.045~0.074 mm, while the remaining steps and process conditions are the same as in Example 1.

[0036] As shown in Table 2, the copper grade of the copper concentrate obtained in this comparative example decreased to 17.15%, the copper recovery rate decreased to 84.67%, and the sulfur content increased to 32.14%. This is because the carrier particles were too fine, resulting in a significantly reduced settling velocity and making it difficult to form a continuous and stable barrier layer at the bottom of the frothy zone. Some fine carrier particles were even carried upwards by bubbles into the copper concentrate, leading to a decrease in copper grade and an increase in sulfur content. This comparison indicates that the carrier particle size must be greater than 0.1 mm to produce an effective physical barrier effect.

[0037] Comparative Example 2 The difference between this comparative example and Example 1 is that the carrier strengthening and suppression treatment in step (2) is omitted. That is, the coarse pyrite obtained in step (1) is directly added to the roughing flotation cell without being slurried with lime slurry. The remaining steps and process conditions are the same as in Example 1.

[0038] As shown in Table 2, the copper grade of the copper concentrate obtained in this comparative example is only 16.39%, the copper recovery rate is 82.81%, and the sulfur content is as high as 35.61%, indicating a significantly inferior separation effect compared to Example 1. This is because the surface of coarse-grained pyrite, which has not been reinforced with lime, naturally possesses a certain degree of hydrophobicity. Under the action of the collector, it will float into the copper concentrate, not only failing to play a blocking role but also directly becoming a source of sulfur pollution. This comparison proves that the carrier must be reinforced with lime to make its surface completely hydrophilic; otherwise, the effect of "only blocking and not floating" cannot be achieved.

[0039] Comparative Example 3 The difference between this comparative example and Example 1 is that the amount of coarse pyrite carrier added in step (3) is 2% of the solid mass of the ore pulp (lower than the lower limit of the scope of this invention), and the remaining steps and process conditions are the same as in Example 1.

[0040] Table 2 shows that the copper grade of the copper concentrate obtained in this comparative example is 17.88%, the copper recovery rate is 85.53%, and the sulfur content is 30.67%. Compared with Example 1, both the copper grade and recovery rate decreased, while the sulfur content increased. This is because when the carrier addition is insufficient, a completely covering physical barrier layer cannot be formed at the bottom of the froth zone, resulting in "channels" or "holes." Some fine-grained pyrite can still pass through the barrier layer and be mechanically carried into the copper concentrate. This comparison illustrates that the carrier addition needs to reach more than 5% to construct a dense barrier layer.

[0041] Comparative Example 4 The difference between this comparative example and Example 1 is that the amount of coarse pyrite carrier added in step (3) is 30% of the solid mass of the ore pulp (higher than the upper limit of the scope of this invention), and the remaining steps and process conditions are the same as in Example 1.

[0042] Table 2 shows that the copper grade of the copper concentrate obtained in this comparative example is 18.89%, the copper recovery rate is reduced to 82.04%, and the sulfur content is 29.59%. Although the sulfur content is improved compared to comparative examples 1-3, the copper recovery rate is significantly reduced. This is because excessive carrier leads to an excessively high concentration of coarse particles in the pulp, increasing the apparent viscosity of the pulp and reducing the stability of the froth layer. At the same time, excessive coarse carrier particles exert mechanical collisions and shearing effects on the bubbles, causing the copper minerals already attached to the bubbles to detach, resulting in copper loss. This comparison indicates that the amount of carrier added should not exceed 20%, otherwise it will interfere with normal flotation kinetics.

[0043] Comparative Example 5 The difference between this comparative example and Example 1 is that no coarse pyrite carrier is added in step (3), and the amount of lime added in the roughing operation section in step (4) is increased to make the slurry pH reach 12.0 (traditional high-alkali process). The remaining steps and process conditions are the same as in Example 1.

[0044] As shown in Table 2, the copper grade of the copper concentrate obtained in this comparative example is only 15.64%, the copper recovery rate is 80.07%, and the sulfur content is as high as 36.65%, with all indicators being the worst. This fully demonstrates that relying solely on lime chemical inhibition cannot effectively solve the mechanical entrainment problem of fine-grained pyrite. In high-alkali and high-viscosity slurry, fine-grained pyrite is still mechanically entrained by bubble clusters and enters the foam product. Increasing the amount of lime actually worsens the floatability of chalcopyrite, leading to a decrease in copper recovery. This comparison highlights the irreplaceable nature of the physical barrier layer introduced in this invention.

[0045] Table 1 Comparison of key parameters between Example 1 and Comparative Examples 1-5 Table 2. Flotation test results of Example 1 and Comparative Examples 1-5 Example 2 This embodiment provides a copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite support, comprising the following steps: (1) Carrier acquisition: A copper-sulfur mixed concentrate (copper grade 5.2%, sulfur grade 42.5%) was used as the feed material for copper-sulfur flotation separation. From the tailings produced by the copper-sulfur mixed concentrate through copper-sulfur flotation separation, coarse pyrite with a particle size of 0.15~0.25 mm was separated by hydrocyclone classification and used as a physical barrier carrier.

[0046] (2) Carrier-enhanced inhibition: The coarse pyrite separated in step (1) is made into coarse pyrite slurry, and lime slurry is added to keep the concentration of coarse pyrite slurry consistent with the concentration of roughing slurry (both are 35%). Stir for 15 min, adjust the pH of the slurry to 11.0, so that a hydrophilic passivation film is generated on the surface of the carrier, and the coarse pyrite carrier with enhanced inhibition is obtained.

[0047] (3) Construction of physical barrier layer: The coarse pyrite carrier obtained in step (1) is added to the roughing flotation cell. The addition position is at the bottom of the roughing flotation cell, and the addition amount is 5% of the solid mass of the pulp in the roughing flotation cell. The coarse pyrite carrier forms a stable physical barrier layer at the bottom of the flotation froth zone. The residence time of the coarse pyrite carrier in the roughing flotation cell is the same as the flotation operation time, and no special carrier circulation loop is set up.

[0048] (4) Copper-sulfur flotation separation: Lime (800 g / t) is added to the flotation system to adjust the pH of the pulp to 9.0, and then copper collector butyl xanthate (100 g / t) and frother pine oil (25 g / t) are added. Copper concentrate is obtained through one roughing operation, three cleaning operations, and two scavenging operations. Lime is added for each cleaning operation, and the amount added at one time is 1 / 3 of the amount of lime used in the roughing operation (about 267 g / t). Copper collector (butyl xanthate, about 33.33 g / t) and frother (pine oil, about 8.33 g / t) are added for each scavenging operation. The ore from the scavenging operation is returned to the roughing operation section in sequence, and the tailings are used as sulfur concentrate to enter the sulfur flotation system.

[0049] (5) Closed-circuit recovery of carrier: After flotation, the coarse pyrite carrier enters the subsequent sulfur flotation system with the tailings and is recovered as sulfur concentrate product. The carrier itself becomes part of the sulfur concentrate and does not need to be separated from the tailings.

[0050] The copper concentrate obtained in this embodiment has a copper grade of 19.59%, a copper recovery rate of 87.94%, and a sulfur content of 29.14%.

[0051] Example 3 This embodiment provides a copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite support, comprising the following steps: (1) Carrier acquisition: A copper-sulfur mixed concentrate (copper grade 5.2%, sulfur grade 42.5%) was used as the feed material for copper-sulfur flotation separation. From the tailings produced by the copper-sulfur mixed concentrate through copper-sulfur flotation separation, coarse pyrite with a particle size of 0.1~0.2 mm was separated by hydrocyclone classification and used as a physical barrier carrier.

[0052] (2) Carrier-enhanced inhibition: The coarse pyrite separated in step (1) is made into coarse pyrite slurry, lime slurry is added, and the concentration of coarse pyrite slurry is kept consistent with that of roughing slurry (both are 35%). Stir for 5 min, adjust the pH of the slurry to 12.0, so that a hydrophilic passivation film is generated on the surface of the carrier, and the coarse pyrite carrier is enhanced and inhibited.

[0053] (3) Construction of physical barrier layer: The coarse pyrite carrier obtained in step (1) is added to the roughing flotation cell. The addition position is at the bottom of the roughing flotation cell, and the addition amount is 20% of the solid mass of the pulp in the roughing flotation cell. The coarse pyrite carrier forms a stable physical barrier layer at the bottom of the flotation froth zone. The residence time of the coarse pyrite carrier in the roughing flotation cell is the same as the flotation operation time, and no special carrier circulation loop is set.

[0054] (4) Copper-sulfur flotation separation: Lime (addition amount of 2500 g / t) is added to the flotation system to adjust the pH of the pulp to 11.0, and then copper collector (a mixture of Z-200 and ethyl xanthate at a mass ratio of 1:1, with a total addition amount of 200 g / t) and frother MIBC (5 g / t) are added. Copper concentrate is obtained through one roughing operation, three cleaning operations, and two scavenging operations. Lime is added for each cleaning operation, with a single addition amount of 1 / 3 of the lime used in the roughing operation (about 833 g / t). Copper collector (a mixture of Z-200 and ethyl xanthate at a mass ratio of 1:1, with a single addition amount of about 66.67 g / t) and frother (MIBC, with a single addition amount of about 1.67 g / t) are added for each scavenging operation. The ore from the scavenging operation is returned to the roughing operation section in sequence, and the tailings are used as sulfur concentrate to enter the sulfur flotation system.

[0055] (5) Closed-circuit recovery of carrier: After flotation, the coarse pyrite carrier enters the subsequent sulfur flotation system with the tailings and is recovered as sulfur concentrate product. The carrier itself becomes part of the sulfur concentrate and does not need to be separated from the tailings.

[0056] The copper concentrate obtained in this embodiment has a copper grade of 20.17%, a copper recovery rate of 87.28%, and a sulfur content of 28.61%.

[0057] Table 3. Flotation test results of Examples 2 and 3 Table 3 shows the flotation test results of Examples 2 and 3. Example 2 used the following parameter combination: carrier particle size 0.15~0.25 mm, enhanced inhibition pH 11.0, addition amount 5%, and roughing pH 9.0. As shown in Table 3, the copper concentrate had a copper grade of 19.59%, a copper recovery rate of 87.94%, and a sulfur content of 29.14%. Compared with Example 1, the copper grade and recovery rate decreased slightly but remained within an acceptable range, indicating that the present invention can still maintain good separation performance at the lower parameter limits, demonstrating the robustness of the process. Example 3 used the following parameter combination: carrier particle size 0.1~0.2 mm, enhanced inhibition pH 12.0, addition amount 20%, and roughing pH 11.0. The copper concentrate had a copper grade of 20.17%, a copper recovery rate of 87.28%, and a sulfur content of 28.61%. The copper grade in Examples 2 and 3 was slightly higher than in Example 1, but the recovery rate was slightly lower. This was due to the enhanced barrier effect under high addition levels and high pH conditions, although high pH slightly inhibited the floatability of chalcopyrite. Overall, the performance indicators of Examples 2 and 3 were superior to all comparative examples and were within industrially acceptable ranges, verifying the scientific validity and industrial feasibility of the parameter range defined in the claims of this invention.

[0058] In summary, the core innovation of this invention lies in obtaining coarse-grained pyrite from within the process and subjecting it to lime-enhanced suppression, thereby forming a stable physical barrier layer at the bottom of the froth zone during flotation. This barrier layer effectively intercepts the mechanical entrainment of fine-grained pyrite through the gravitational settling of high-density particles and the steric hindrance effect, compensating for the kinetic lag of traditional lime-based chemical suppression. A step-by-step comparison of the examples and comparative examples fully demonstrates that the constraints on the three key parameters—carrier particle size, enhanced suppression, and dosage—have a clear physicochemical basis; the absence or deviation from any one of these parameters will significantly worsen the separation performance.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A copper-sulfur flotation separation method based on physical barrier enhancement using coarse-grained pyrite carrier, characterized in that, Includes the following steps: (1) Carrier acquisition: coarse pyrite is separated from the tailings or sulfur concentrate produced by copper-sulfur separation operation and used as a physical barrier carrier; (2) Carrier-enhanced inhibition treatment: The coarse pyrite obtained in step (1) is made into coarse pyrite slurry, lime slurry is added, and the pH value of the coarse pyrite slurry is adjusted to 11.0~12.0 under stirring conditions to obtain coarse pyrite carrier with enhanced inhibition. (3) Constructing a physical barrier layer: The coarse pyrite carrier obtained in step (2) is added to the copper-sulfur separation roughing section so that the coarse pyrite carrier forms a physical barrier layer at the bottom of the flotation froth zone. (4) Copper-sulfur flotation separation: The copper-sulfur mixed concentrate is slurry prepared and sent to the copper-sulfur separation roughing section. Lime is added to adjust the pH value of the slurry to 9.0~11.0, and then copper collector and frother are added for flotation separation to obtain copper concentrate.

2. The method according to claim 1, characterized in that: In step (1), the separation method is either hierarchical or reselection.

3. The method according to claim 1, characterized in that: In step (1), the coarse pyrite has a particle size of 0.1~0.3 mm.

4. The method according to claim 1, characterized in that: In step (2), the concentration of the coarse pyrite slurry is consistent with the concentration of the slurry in the copper-sulfur separation roughing section, and the concentration of the slurry in the copper-sulfur separation roughing section is 25%~45%.

5. The method according to claim 1, characterized in that: In step (2), the stirring time is 5 to 15 minutes.

6. The method according to claim 1, characterized in that: In step (3), based on the solid mass of the slurry in the copper-sulfur separation roughing operation section, the amount of coarse pyrite carrier added is 5%~20%, and the addition location is the bottom of the flotation cell in the copper-sulfur separation roughing operation section or the slurry inlet.

7. The method according to claim 1, characterized in that: In step (4), the copper collector is at least one of ethyl thiocyanate, sodium ethyl xanthate, and sodium butyl xanthate; the foaming agent is methyl isobutyl methanol or pine oil; based on the dry mass of copper-sulfur mixed concentrate, the amount of copper collector added is 20~200 g / t, and the amount of foaming agent added is 5~30 g / t.

8. The method according to claim 1, characterized in that: In step (4), the flotation separation includes roughing, cleaning and scavenging operations in sequence; the roughing operation is carried out once, the cleaning operation is carried out 2 to 4 times, and lime is added each time the cleaning operation is carried out; the scavenging operation is carried out 2 to 4 times, and copper collector and frother are added each time the scavenging operation is carried out; the middlings produced by scavenging are returned to the copper-sulfur separation roughing operation section in step (3), and the tailings are used as sulfur concentrate or sent to the sulfur flotation system.

9. The method according to claim 8, characterized in that, The amount of lime added in a single operation during the fine separation process is 25% to 50% of the amount added during the roughing process; the amount of copper collector added in a single operation during the scavenging process is 25% to 50% of the amount added during the roughing process; and the amount of frother added in a single operation during the scavenging process is 25% to 50% of the amount added during the roughing process.

10. The method according to any one of claims 1 to 9, characterized in that, In step (4), after the flotation separation is completed, the coarse pyrite carrier is incorporated into the sulfur concentrate along with the tailings or enters the sulfur flotation system as a closed-loop recovery of the sulfur concentrate product.

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