A method for zinc beneficiation from high-sulfur copper-zinc separation tailings

Abstract

This invention belongs to the field of mineral processing technology, specifically relating to a method for zinc beneficiation from high-sulfur copper-zinc separation tailings. Utilizing a self-developed flotation machine, the method includes multiple steps such as vertical mill decanting, copper sulfate agitation and activation, lime addition for slurry conditioning, slurry heating, zinc-sulfur separation roughing, zinc cleaning, and zinc scavenging. Increasing the slurry temperature rapidly oxidizes the pyrite surface, increasing its hydrophilicity. Simultaneously, raising the slurry temperature improves the activation efficiency of copper sulfate on sphalerite, shortening the flotation process and ensuring zinc recovery. Increasing the slurry temperature saves on copper sulfate usage, reducing environmental impact and embodying green development. Compared to other decanting methods, using a vertical mill for mechanical decanting not only saves on activated carbon usage, reducing carbon emissions and being more environmentally friendly, but also offers lower investment costs and is more economical than thickeners due to their higher infrastructure costs.

Description

Technical Field

[0001] This solution belongs to the field of mineral processing technology, specifically involving a method for zinc beneficiation from high-sulfur copper-zinc separation tailings. Background Technology

[0002] Pyrite-type high-sulfur copper-zinc sulfide ore, with copper minerals mainly in the form of chalcopyrite and zinc minerals mainly in the form of sphalerite.

[0003] In the mineral processing technology, copper-zinc mixed flotation is used to remove a large amount of non-target minerals. Then, combined depressants are added to carry out copper flotation and zinc suppression operations. Finally, copper tailings are activated with copper sulfate to suppress sulfur and flotate zinc to obtain qualified zinc concentrate.

[0004] For example, patent number 202110520194.8 discloses a flotation separation method for high-sulfur copper-zinc ore. The method includes the following steps: (1) grinding the crushed high-sulfur copper-zinc ore to obtain a slurry; (2) adding sodium sulfite and zinc sulfate inhibitors, butyl xanthate collector, and ester collector frother to the slurry at a pH of 7-8 for copper roughing to obtain copper rough concentrate slurry and roughing tailings slurry; (3) subjecting the copper rough concentrate slurry to three cleaning operations to obtain copper concentrate; (4) subjecting the roughing tailings slurry to two copper scavenging operations to obtain copper scavenged tailings; (5) adding lime, copper sulfate, butyl xanthate collector, and No. 2 oil to the copper scavenged tailings for zinc roughing to obtain zinc rough concentrate slurry and zinc roughing tailings slurry; (6) subjecting the zinc rough concentrate slurry to three cleaning operations to obtain zinc concentrate; (7) subjecting the zinc roughing tailings slurry to two zinc scavenging operations to obtain zinc scavenged tailings. This invention achieves efficient flotation separation of copper and zinc, and recycles the copper and zinc flotation effluent.

[0005] The aforementioned mineral processing technology has the following problems: First, the flotation process is relatively long, with zinc processing at the very end. Excessive use of reagents in the upstream separation process negatively impacts zinc-sulfur separation, leading to severe sulfur entrainment and insufficient zinc enrichment. Second, in low winter temperatures, the suppressed sphalerite is difficult to activate. Increasing the amount of copper sulfate can reduce activation time, but the effect is limited, resulting in high tailings runoff and low zinc recovery. Furthermore, as the most crucial piece of equipment in the mineral processing technology, improvements to the flotation machine, in conjunction with the process itself, can further enhance the beneficiation efficiency. Summary of the Invention

[0006] This solution provides a method for zinc beneficiation from high-sulfur copper-zinc separation tailings to address the problem of low zinc recovery rates during winter when temperatures are low.

[0007] To achieve the above objectives, this solution provides a method for zinc beneficiation from high-sulfur copper-zinc separation tailings, comprising the following steps:

[0008] Step S10, vertical mill de-refining: The copper-zinc separation tailings are prepared into dry ore and fed into the vertical mill with water at a ratio of 2:1 for grinding.

[0009] Step S20, Copper sulfate stirring and activation: The grinding product obtained from grinding in step S10 is fed into the No. 1 mixing tank. Copper sulfate is added at the slurry inlet of the No. 1 mixing tank at a rate of 400-600 g / t, and the stirring time is controlled at 6-8 minutes.

[0010] Step S30, Lime Addition and Slurry Adjustment: The slurry obtained in step S20 is fed into mixing tank No. 2, and lime milk is added at a rate of 1500-1800g / t. After stirring evenly, the pH value of the slurry is adjusted to 11.5-11.8.

[0011] Step S40, slurry heating: The high-alkali slurry obtained in step S30 is heated, and the heating temperature is controlled at 45-50℃;

[0012] Step S50, zinc-sulfur separation roughing: The heated slurry obtained in step S40 is fed into a flotation machine, and a collector and a frother are added. The amount of the collector is 2-4 g / t, and the amount of the frother is 1-4 g / t. After stirring for 3 minutes and 1 minute respectively, zinc-sulfur separation is carried out to obtain zinc rough concentrate and zinc rough tailings.

[0013] Step S60, Zinc Refinement: The zinc rough concentrate obtained in step S50 is fed into a flotation machine for four refinements. During the second and third refinements, lime slurry is added to the flotation machine in sequence to adjust the pH of the pulp to 11.5-11.7, thereby obtaining zinc concentrate and zinc middlings. The zinc middlings are then returned to the previous step.

[0014] Step S70, Zinc Scavenging: The zinc roughing tailings obtained in step S60 are subjected to 2-3 stages of zinc scavenging. In each stage of scavenging, the amount of collector is 1-2 g / t and the amount of frother is 1-3 g / t. The zinc scavenging process yields zinc ore and zinc tailings. The zinc ore is then returned to the previous stage of the process. The zinc tailings are the sulfur concentrate.

[0015] Compared to traditional methods, this invention employs a pre-selection slurry heating technology. By increasing the slurry temperature, the surface of pyrite is rapidly oxidized, increasing its hydrophilicity. Simultaneously, raising the slurry temperature improves the activation efficiency of copper sulfate on sphalerite, shortening the flotation process and ensuring zinc recovery. Increasing the slurry temperature saves on copper sulfate usage, reducing environmental impact and embodying green development principles. Using a vertical roller mill for mechanical decanting, compared to other decanting methods, not only saves on activated carbon usage, thus reducing carbon emissions and being more environmentally friendly, but also offers lower investment costs and is more economical than the high infrastructure costs of thickeners.

[0016] Meanwhile, in the zinc beneficiation process, lime is added in stages during the second and third beneficiation stages to maintain high alkalinity and continuously suppress pyrite. Because the slurry volume is relatively small during the beneficiation stages, adding a small amount of lime ensures effective pyrite suppression throughout the entire process, thus improving the quality of the zinc concentrate.

[0017] Furthermore, the collector is xanthate, and the frother is BK201 frother. These are commonly used collectors and frothers, readily available, and cost-effective.

[0018] Furthermore, in step S10, a vertical spiral stirred mill is used to grind, scrub, and de-drug the surface of the mineral particles in the high-sulfur copper-zinc separation tailings. The grinding media consists of composite ceramic balls with a diameter of 10-15 mm. The composite ceramic balls have a good de-drug removal effect.

[0019] Furthermore, in step S10, the pH value of the slurry during grinding is controlled at 7.0-8.0. Grinding and de-drug removal are more effective at this pH value.

[0020] Furthermore, the pH of the slurry was determined using the acid-base neutralization method. This method is simple and yields accurate results.

[0021] Furthermore, the flotation machine includes a housing, a drive motor, an impeller, a stirring mechanism, and a sleeve. The drive motor is fixed to the housing, and its output shaft passes through the sleeve. The impeller is coaxially connected to the output shaft of the drive motor and forms a pump within the sleeve. The stirring mechanism is fixed to the free end of the drive motor's output shaft. It also includes an inner chamber located within the housing, forming an insulation cavity between the inner chamber and the housing. A hot air duct is installed within the insulation cavity. The sleeve and the insulation cavity are connected by a flexible air inlet pipe. The inner chamber includes a fixed plate and at least one movable plate, which are sealed together by a flexible component. An elastic component is installed between the movable plate and the housing. An air outlet pipe is also provided at the top of the housing, with a strip-shaped air outlet on its side wall, and the air outlet pipe is connected to the insulation cavity.

[0022] The principle behind this solution is:

[0023] First, a hot air blower is connected to the insulation chamber via a hot air duct. Then, the slurry and reagents are poured into the chamber, and the drive motor is started. The motor drives the stirring mechanism to mix the materials, and simultaneously, the impeller rotates, generating a pressure difference that pumps hot air from the insulation chamber into the chamber. The hot air comes into full contact with the minerals, forming mineralized bubbles that rise and enter the separation zone, where they accumulate to form a foam layer. Finally, the top vent pipe blows the foam layer into a collection tank for further processing.

[0024] Compared to traditional flotation machines, the main difference in this design lies in the addition of an inner chamber, forming an insulated cavity to heat the slurry and achieve better screening results (especially in winter). The inner chamber features a movable plate and flexible components, working in conjunction with springs. As the slurry level decreases, the movable plate moves, reducing the effective volume of the chamber and ensuring the froth layer is always separated. The air inlet pipe connects to the casing, allowing hot air to enter the chamber. Combined with the stirring mechanism, this ensures thorough contact and heating of the minerals, resulting in excellent heating. Finally, replacing the traditional flotation plates with an air outlet pipe allows the froth layer to be blown out by airflow, rather than being physically scraped off. This offers two main advantages: 1. It avoids the slurry sticking to the flotation plate during physical scraping, which increases the plate size and causes slurry that is not part of the froth layer to be scraped away; 2. The hot air from the outlet pipe forms an air curtain, significantly slowing down the temperature drop within the chamber and ensuring optimal mineral processing.

[0025] Furthermore, it also includes an adjusting motor, which is fixed to the housing, and the air outlet pipe is rotatably mounted on the housing, with the air outlet pipe coaxially connected to the output shaft of the adjusting motor. The angle of the air outlet pipe can be adjusted by adjusting the motor, making operation convenient. Attached Figure Description

[0026] Figure 1 This is a top view of the flotation machine in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the flotation machine in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the flotation machine in an embodiment of the present invention. Detailed Implementation

[0029] The following detailed explanation illustrates the specific implementation methods:

[0030] The reference numerals in the accompanying drawings include: box body 10, inner box 20, elastic element 21, hot air pipe 22, flexible element 23, air inlet pipe 24, drive motor 30, slurry inlet pipe 31, stirring mechanism 32, regulating motor 40, air outlet pipe 41, air outlet 42, and collection tank 50.

[0031] Example 1

[0032] This invention discloses a method for zinc beneficiation from high-sulfur copper-zinc separation tailings, which particularly relies on a novel flotation machine. For example... Figure 1 , Figure 2 and Figure 3As shown, it is basically the same as the existing flotation machine, including a housing 10, a drive motor 30, an impeller, a stirring mechanism 32, and a sleeve. The drive motor 30 is fixed to the housing 10, and the output shaft of the drive motor 30 passes through the sleeve. The impeller is coaxially connected to the output shaft of the drive motor 30, and the impeller is located inside the sleeve to form a pump. The stirring mechanism 32 is fixed at the lowest end of the output shaft of the drive motor 30. Other existing structures such as the inlet pipe 31 are also present, and will not be described in detail; please refer to existing flotation machines.

[0033] The main difference lies in the inclusion of an inner casing 20, which is slightly smaller than the outer casing 10 and is welded inside the outer casing 10. This creates an insulated cavity between the inner casing 20 and the outer casing 10, and a hot air duct 22 is installed inside the insulated cavity. In use, it can be connected to a hot air blower through the hot air duct 22.

[0034] The sleeve and the insulation chamber are connected by a flexible air inlet pipe 24. This increases the pulp temperature, causing rapid oxidation of the pyrite surface and increasing its hydrophilicity. Simultaneously, raising the pulp temperature improves the activation efficiency of copper sulfate on sphalerite, shortening the flotation process and ensuring zinc recovery. If necessary, a thermometer can be installed inside the chamber 10 to easily monitor the pulp temperature. The flexible air inlet pipe 24 can be easily bent; a foldable pipe is also possible.

[0035] The inner box 20 includes a fixed plate and three movable plates, which are sealed to the fixed plate by flexible components 23. The flexible components 23 can be appropriately long, with a ring at both the top and bottom, and are made of rubber, allowing for high deformation. Additionally, an elastic component 21 is provided between the movable plates and the box body 10; a common stainless steel spring is sufficient for this purpose, ensuring a long service life.

[0036] An air outlet pipe 41 is also provided at the top of the housing 10. A strip-shaped air outlet 42 is provided on the side wall of the air outlet pipe 41, and the air outlet pipe 41 is connected to the insulation cavity. It is worth noting that the air outlet 42 of the air outlet pipe 41 should be as horizontal as possible to the surface of the slurry. The size of the air outlet 42 should not be too large, otherwise the airflow may be insufficient. Those skilled in the art can adjust this according to the actual situation. In addition, a separate adjusting motor 40, using a servo motor, can be provided for convenient adjustment in two directions. The adjusting motor 40 is fixed to the housing 10, and then the air outlet pipe 41 is rotatably mounted on the housing 10, with the air outlet pipe 41 coaxially connected to the output shaft of the adjusting motor 40. In this way, the angle of the air outlet pipe 41 can be adjusted by adjusting the motor 40, making operation convenient.

[0037] In practical use, firstly, the hot air blower is connected to the insulation cavity via a hot air duct. Then, the slurry and reagents are poured into the chamber 10, and the drive motor is started. The motor drives the stirring mechanism 32 to mix the materials. Simultaneously, the impeller rotates along with the slurry, generating a pressure difference that pumps hot air from the insulation cavity into the chamber. The hot air comes into full contact with the minerals, forming mineralized bubbles that rise and enter the separation zone, where they accumulate to form a foam layer. Finally, the top air outlet blows the foam layer into the collection tank 50 for further processing.

[0038] In winter conditions with a temperature of around 3°C inside the factory, a specific method for zinc beneficiation from high-sulfur copper-zinc separation tailings includes the following steps:

[0039] Step S10, Vertical Mill De-refining: The copper-zinc separation tailings are prepared into dry ore and fed into a vertical mill with water at a ratio of 2:1 for grinding; a vertical spiral stirred mill is used to grind, scrub, and de-refine the surface of the mineral particles in the high-sulfur copper-zinc separation tailings, and the grinding media consists of φ10-15mm composite ceramic balls.

[0040] Step S20, Copper sulfate stirring and activation: The grinding product obtained from grinding in step S10 is fed into mixing tank No. 1. Copper sulfate is added at the slurry inlet of mixing tank No. 1 at a rate of 500g / t, and the stirring time is controlled at 7 minutes.

[0041] Step S30, Lime Addition and Slurry Adjustment: The slurry obtained in step S20 is fed into mixing tank No. 2, and lime milk is added at a rate of 1600g / t. After stirring evenly, the pH value of the slurry is adjusted to 11.7.

[0042] Step S40, slurry heating: The high-alkali slurry obtained in step S30 is heated, and the heating temperature is controlled at 48℃;

[0043] Step S50, zinc-sulfur separation roughing: The heated slurry obtained in step S40 is fed into a flotation machine, and a collector and a frother are added. The amount of the collector is 3g / t and the amount of the frother is 3g / t. After stirring for 3 minutes and 1 minute respectively, zinc-sulfur separation is carried out to obtain zinc rough concentrate and zinc rough tailings.

[0044] Step S60, Zinc Refinement: The zinc rough concentrate obtained in step S50 is fed into a flotation machine for four refinements. During the second and third refinements, lime slurry is added to the flotation machine in sequence to adjust the pH of the pulp to 11.6, thereby obtaining zinc concentrate and zinc middlings. The zinc middlings are then returned to the previous step.

[0045] Step S70, Zinc Scavenging: The zinc roughing tailings obtained in step S60 are subjected to a 3-stage zinc scavenging operation. In each scavenging operation, the amount of collector is 2g / t and the amount of frother is 3g / t. The zinc scavenging operation is carried out to obtain zinc ore and zinc tailings. The zinc ore is returned to the previous operation in sequence. The zinc tailings are the sulfur concentrate.

[0046] Example 2

[0047] The difference between this embodiment and Embodiment 1 is that:

[0048] 1. In step S20, the amount added is 400g / t, and the stirring time is controlled at 6 minutes;

[0049] 2. In step S30, add lime slurry at a rate of 1500g / t, stir evenly, and adjust the pH of the slurry to 11.5.

[0050] 3. In step S40, the heating temperature is controlled at 45℃;

[0051] 4. In step S50, the amount of collector is 2g / t, and the amount of foaming agent is 1g / t;

[0052] 5. In step S60, adjust the pH of the slurry to 11.5;

[0053] 6. In step S70, the amount of collector is 1 g / t and the amount of foaming agent is 1 g / t.

[0054] The comparative test used a traditional method, without heating, and employed a conventional flotation machine.

[0055] The specific results are shown in the table below:

[0056]

[0057] Therefore, the process of this invention can eliminate the influence of upstream processes and obtain stable zinc indicators. Compared with traditional methods, this invention uses a pre-selection slurry heating technology. By increasing the slurry temperature, the surface of pyrite is rapidly oxidized, increasing the hydrophilicity of pyrite. At the same time, raising the slurry temperature can improve the activation efficiency of copper sulfate on sphalerite, shorten the flotation process, and ensure zinc recovery. Increasing the slurry temperature can save the amount of copper sulfate used, reducing the impact on the surrounding environment and reflecting green development. Compared with other deagent methods, using a vertical mill for mechanical deagenting not only saves the amount of activated carbon used, which is conducive to reducing carbon emissions and is more environmentally friendly, but also has a lower investment cost and is more economical than the high infrastructure cost of a thickener.

[0058] Meanwhile, in the zinc beneficiation process, lime is added in stages during the second and third beneficiation stages to maintain high alkalinity and continuously suppress pyrite. Because the slurry volume is relatively small during the beneficiation stages, adding a small amount of lime ensures effective pyrite suppression throughout the entire process, thus improving the quality of the zinc concentrate.

[0059] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for zinc beneficiation from high-sulfur copper-zinc separation tailings, characterized in that, Includes the following steps: Step S10, vertical mill de-refining: The copper-zinc separation tailings are prepared into dry ore and fed into the vertical mill with water at a ratio of 2:1 for grinding. Step S20, Copper sulfate stirring and activation: The grinding product obtained from grinding in step S10 is fed into the No. 1 mixing tank. Copper sulfate is added at the slurry inlet of the No. 1 mixing tank at a rate of 400-600 g / t, and the stirring time is controlled at 6-8 minutes. Step S30, Lime Addition and Slurry Adjustment: The slurry obtained in step S20 is fed into mixing tank No. 2, and lime milk is added at a rate of 1500-1800g / t. After stirring evenly, the pH value of the slurry is adjusted to 11.5-11.

8. Step S40, slurry heating: The high-alkali slurry obtained in step S30 is heated, and the heating temperature is controlled at 45-50℃; Step S50, zinc-sulfur separation roughing: The heated slurry obtained in step S40 is fed into a flotation machine, and a collector and a frother are added. The amount of the collector is 2-4 g / t, and the amount of the frother is 1-4 g / t. After stirring for 3 minutes and 1 minute respectively, zinc-sulfur separation is carried out to obtain zinc rough concentrate and zinc rough tailings. Step S60, Zinc Refinement: The zinc rough concentrate obtained in step S50 is fed into a flotation machine for four refinements. During the second and third refinements, lime slurry is added to the flotation machine in sequence to adjust the pH of the pulp to 11.5-11.7, thereby obtaining zinc concentrate and zinc middlings. The zinc middlings are then returned to the previous step. Step S70, Zinc Scavenging: The zinc roughing tailings obtained in step S60 are subjected to 2-3 stages of zinc scavenging. In each stage of scavenging, the amount of collector is 1-2 g / t and the amount of frother is 1-3 g / t. The zinc scavenging process is carried out to obtain zinc ore and zinc tailings. The zinc ore is returned to the previous stage in sequence. The zinc tailings are the sulfur concentrate. The flotation machine includes a housing, a drive motor, an impeller, a stirring mechanism, and a sleeve. The drive motor is fixed to the housing, and its output shaft passes through the sleeve. The impeller is coaxially connected to the output shaft of the drive motor and forms a pump within the sleeve. The stirring mechanism is fixed to the free end of the drive motor's output shaft. The machine also includes an inner chamber located within the housing, forming an insulation cavity between the inner chamber and the housing. A hot air duct is installed within the insulation cavity. The sleeve and the insulation cavity are connected by a flexible air inlet pipe. The inner chamber includes a fixed plate and at least one movable plate, which are sealed together by a flexible component. An elastic component is installed between the movable plate and the housing. An air outlet pipe is also provided at the top of the housing. A strip-shaped air outlet is located on the side wall of the air outlet pipe, which is connected to the insulation cavity. The hot air blown out by the air outlet pipe forms an air curtain.

2. The method for zinc beneficiation from high-sulfur copper-zinc separation tailings according to claim 1, characterized in that: The collector is xanthate, and the foaming agent is BK201 foaming agent.

3. The method for zinc beneficiation from high-sulfur copper-zinc separation tailings according to claim 1, characterized in that: In step S10, a vertical spiral stirred mill is used to grind, scrub, and remove reagents from the surface of mineral particles in the high-sulfur copper-zinc separation tailings. The grinding media consists of composite ceramic balls with a diameter of φ10-15mm.

4. The method for zinc beneficiation from high-sulfur copper-zinc separation tailings according to claim 3, characterized in that: In step S10, the pH value of the slurry during grinding is controlled at 7.0-8.

0.

5. A method for zinc beneficiation from high-sulfur copper-zinc separation tailings according to claim 4, characterized in that: The pH of the slurry was determined using the acid-base neutralization method.

6. The method for zinc beneficiation from high-sulfur copper-zinc separation tailings according to claim 1, characterized in that: It also includes an adjusting motor, which is fixed on the housing, and the air outlet pipe is rotatably mounted on the housing, and the air outlet pipe is coaxially connected to the output shaft of the adjusting motor.

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