Method for improving oxygen utilization rate of oxygenation stirring in zinc leaching iron precipitation process

Abstract

The invention relates to a method for improving the oxygen utilization rate of oxygenation stirring in a zinc leaching iron precipitation process, and relates to the technical field of oxygenation stirring. The method comprises the following steps: a) in a leaching tank, introducing oxygen into a leaching solution containing ferrous iron through an aeration assembly head arranged at the bottom of the tank; b) stirring the leachate through a stirring assembly positioned above the aeration assembly; c) applying a high-voltage electrostatic field to at least one pair of electrode plates immersed in the leachate, wherein the electrode plates are insulated from the tank wall and are obliquely arranged; d) monitoring the surface zeta potential of the oxygen bubble in real time by using an online zeta potential instrument; and e) based on the zeta potential value monitored in the step d), dynamically adjusting the intensity of the high-voltage electrostatic field in the step c) through a controller, so that the zeta potential on the surface of the oxygen bubble is stabilized in a target range of-40mV to-25mV, and controlling the pH value of the leachate to be maintained at 2.5-3.5 in the whole process of stirring, aerating and applying the electrostatic field. The method can effectively improve the oxygen utilization rate.

Description

Technical Field

[0001] This application relates to the field of oxygenation and stirring technology, and in particular to a method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process. Background Technology

[0002] In fields such as the zinc leaching process and the iron deposition process, oxygenation and agitation are crucial for ensuring smooth reaction and maintaining the normal function of the system. Current mainstream oxygenation and agitation technologies improve oxygen utilization by optimizing the agitator structure, adjusting aeration parameters, and modifying system characteristics. However, they generally suffer from the following problems: oxygen bubbles tend to coalesce in the liquid, leading to increased bubble diameter, faster rising speed, and shorter contact time with reactants; simultaneously, there is a lack of effective adsorption between the bubbles and reactants, making it difficult for oxygen to be quickly and fully absorbed by the reactants. A large amount of oxygen escapes from the liquid surface without participating in the reaction, resulting in wasted oxygen resources and increased production operating costs.

[0003] In addition, existing technologies also include methods to reduce gas-liquid interfacial tension and disperse bubbles by adding surfactants. However, the main function of surfactants is to improve the dispersion of bubbles, but they cannot actively enhance the adsorption capacity of bubbles and reactants. Furthermore, some surfactants may have adverse effects on the zinc leaching process, thus limiting their applicability.

[0004] Therefore, there is an urgent need for an oxygenation and stirring optimization method that can fundamentally enhance the interaction between oxygen bubbles and reactants, effectively improve oxygen utilization, and has no side effects. Summary of the Invention

[0005] To address or partially address the problems existing in the related technologies, this application provides a method for improving the oxygen utilization rate during oxygenation and stirring in the zinc leaching and iron deposition process, which can effectively improve the oxygen utilization rate.

[0006] This application discloses a method for improving the oxygen utilization rate during oxygenation and stirring in a zinc leaching and iron deposition process, the method comprising the following steps: a) In the leaching tank, oxygen is introduced into the leaching solution containing ferrous iron through an aeration assembly head located at the bottom of the tank to generate initial oxygen bubbles; b) The leachate is stirred by a stirring component located above the aeration component to disperse oxygen bubbles; c) By applying a high-voltage electrostatic field to at least one pair of electrode plates immersed in the leachate, the electrode plates being insulated from the tank wall and inclined; d) Monitor the surface zeta potential of the oxygen bubble in real time using an online zeta potential meter; e) Based on the zeta potential value monitored in step d), the intensity of the high voltage electrostatic field mentioned in step c) is dynamically adjusted by the controller to stabilize the surface zeta potential of the oxygen bubble within the target range of -40mV to -25mV. Throughout the process of stirring, aeration, and applying an electrostatic field, the pH value of the leachate is controlled to be maintained between 2.5 and 3.5 to promote the oxidation reaction of ferrous ions.

[0007] The target range for the Zeta potential (-40mV ~ -25mV) is based on the fact that the interaction forces between particles (including bubbles) are mainly determined by van der Waals attraction (leading to aggregation) and double-layer repulsion (preventing aggregation). The larger the absolute value of the Zeta potential, the stronger the double-layer repulsion.

[0008] If the absolute value is too low (e.g., >-25mV): the repulsive force is insufficient, and the bubbles are prone to coalescing due to Brownian motion and turbulent collisions, turning back into large bubbles and losing their specific surface area advantage.

[0009] Excessively high absolute values ​​(e.g., <-40mV): Although the bubbles are very stable, excessively strong negative charges may cause electrostatic repulsion against the positively charged Fe²⁺, potentially slightly hindering the adsorption of reactants at the gas-liquid interface. Furthermore, maintaining excessively high zeta potentials may require higher electric field strengths, leading to uneconomical energy consumption.

[0010] Therefore, the range of -40mV to -25mV can ensure sufficient electrostatic stability of the bubbles to prevent aggregation, maintain efficient reaction kinetics, and take into account energy consumption.

[0011] Furthermore, in step a), the aeration assembly includes several sets of acid-resistant microbubble aerators, which are evenly arranged along the bottom of the leaching tank. This design promotes uniform oxygen distribution within the reaction area, avoids airflow short-circuiting or dead zones, and maximizes the space utilization of the entire reactor.

[0012] Furthermore, in step c), the spacing of the electrode plates is set according to the diameter of the leaching tank to ensure that the high-voltage electrostatic field can uniformly cover the leaching solution area. By employing "tilt setting" and "spacing setting," the aim is to optimize the distribution of electric field lines in the complex fluid environment and ensure that the electric field strength is relatively uniform throughout the entire reaction area.

[0013] Furthermore, the high-voltage electrostatic field is generated by a high-voltage electrostatic generator through a titanium-coated acid-resistant electrode plate.

[0014] Furthermore, the stirring assembly includes a corrosion-resistant stirring motor, a duplex stainless steel stirring shaft, and an anchor-turbine composite stirring paddle, which is located above the aeration head. The turbine paddle provides strong radial flow and shear force, responsible for breaking up and dispersing bubbles; the anchor paddle, located close to the tank wall, generates strong axial circulating flow, eliminates dead zones, and ensures that bubbles and Fe²⁺ are fully mixed globally.

[0015] Furthermore, the aeration flow rate of the acid-resistant microbubble aerator is adjusted according to the initial Fe²⁺ concentration in the leachate: when the Fe²⁺ concentration is >10 g / L, the aeration flow rate is 1.2~2.0 m³ / h; when the Fe²⁺ concentration is <10 g / L, the aeration flow rate is 0.5~1.2 m³ / h. A high Fe²⁺ concentration requires more oxygen to participate in the reaction, therefore it is necessary to increase the oxygen supply rate (increase the aeration flow rate) to ensure that the reaction rate is not limited by oxygen supply.

[0016] Further, in step c), when activating the high-voltage electrostatic field, the initial voltage is adjusted according to the initial pH value of the leachate: when the initial pH value is less than 2.5, the initial voltage is 15~20kV; when the initial pH value is greater than 3.0, the initial voltage is 10~15kV; wherein, the initial pH value is the pH value measured before or at the beginning of step a). The lower the pH, the higher the H⁺ concentration, the stronger the conductivity of the solution, and the greater the current leakage. In order to establish an electric field strength sufficient to regulate the zeta potential in a more conductive solution, a higher initial voltage needs to be applied.

[0017] Furthermore, the initial Fe²⁺ concentration in the leachate is 3~8 g / L, and the initial pH is 1.5~3.5.

[0018] The beneficial effects of this application are: 1. This method involves introducing microbubbles of oxygen into the bottom of the leaching tank while simultaneously applying a controllable high-voltage electrostatic field to the leachate, and monitoring the surface potential of the oxygen bubbles in real time using an online zeta potential meter. Through a closed-loop control system, the electrostatic field strength is dynamically adjusted to stabilize the zeta potential of the oxygen bubbles within the optimal range of -40mV to -25mV. During this process, the pH value of the leachate is controlled between 2.5 and 3.5.

[0019] This method actively increases the electrostatic charge on the surface of oxygen bubbles using a high-voltage electrostatic field, creating a strong electrostatic adsorption between the bubbles and reactants with opposite charges, effectively preventing bubble separation. Simultaneously, the repulsion between charged bubbles due to like charges prevents bubble aggregation, maintains a small bubble morphology, reduces rising speed, and prolongs bubble residence time in the liquid, fundamentally solving the oxygen escape problem. Experimental verification shows that using this method, electrostatic adsorption allows oxygen to directly participate in the Fe²⁺ oxidation reaction on the bubble surface, reducing oxygen migration loss in the liquid phase. Oxygen utilization rate increases from the traditional 15%~25% to 50%~70%, and oxygen consumption decreases by 45%~60%. Furthermore, optimized stirring and aeration parameters reduce energy consumption by 30%~40%, significantly lowering process costs. The increased Fe²⁺ oxidation rate shortens the iron deposition cycle from the traditional 6~10 hours to 2~4 hours, improving production efficiency by over 50%.

[0020] 2. This method controls the charge through an electrostatic field, does not rely on specific chemical reagents, and will not adversely affect the zinc leaching and iron precipitation process. It can be modified based on existing oxygenation and stirring equipment, with low modification costs and easy promotion. Detailed Implementation

[0021] The embodiments of this application will now be described in more detail with reference to the examples. While embodiments of this application are shown in the examples, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0022] Example 1 This embodiment was carried out in a 100m³ corrosion-resistant leaching tank. The leaching solution composition was: an initial Fe²⁺ concentration of approximately 5g / L, a zinc ion concentration of approximately 80g / L, a sulfuric acid system, and an initial pH of 3.0.

[0023] The specific implementation process is as follows: a) Aeration Step: Twelve acid-resistant microbubble aerators, each with a pore size of 100 μm, are evenly distributed at the bottom of the tank. These aerators are connected to an oxygen source outside the leaching tank via an anti-corrosion gas delivery pipeline, allowing oxygen to be introduced into the leachate. Based on the initial Fe²⁺ concentration (5 g / L, less than 10 g / L), the total aeration flow rate is set to 0.8 m³ / h, generating a large number of initial high specific surface area oxygen bubbles.

[0024] b) Agitation Step: Start the agitation unit located above the aeration head. This unit is driven by a corrosion-resistant motor and connected to an anchor-turbine composite agitator via a duplex stainless steel agitator shaft. It gently and thoroughly agitates the leachate at a speed of 500 r / min, ensuring uniform dispersion of oxygen bubbles.

[0025] c) Applying the electrostatic field: Simultaneously activate the high-voltage electrostatic generator to apply a high-voltage electrostatic field through a pair of titanium-coated acid-resistant electrode plates immersed in the liquid. The electrode plates are isolated from the tank wall by a polytetrafluoroethylene insulation layer and are set at a 75° angle, with a spacing of 1.2 meters based on the tank diameter. The initial voltage is set to 12kV based on an initial pH of 3.0.

[0026] d) Monitoring and Control Procedures: The online zeta potential meter begins real-time monitoring of the surface zeta potential of the oxygen bubble, with an initial reading of -18mV. Upon receiving the signal, the data processor automatically fine-tunes the output of the high-voltage electrostatic generator via the controller, stabilizing the electrostatic field strength at a level that results in a zeta potential of -32mV.

[0027] e) pH control: During the entire reaction process, the pH of the leachate is measured every fifteen minutes. The pH is adjusted by using sodium hydroxide or sulfuric acid (the same below) to stabilize the pH value of the leachate within the range of 3.0±0.1.

[0028] Technical effects: After the reaction lasted for 3.5 hours, the Fe²⁺ concentration in the leachate was found to have dropped below 0.1 g / L, meeting the requirements for iron deposition. Compared to the traditional process without an electrostatic field (which typically takes 7 hours), the iron deposition cycle was shortened by 50%. Calculations showed that the oxygen consumption in this embodiment was reduced by approximately 48% compared to the traditional method.

[0029] Example 2 This embodiment was carried out in a 100m³ leaching tank for treating a high-iron content leachate. The leachate composition was: an initial Fe²⁺ concentration as high as 15g / L, and an initial pH value of 2.2.

[0030] The specific implementation process is as follows: a) Aeration steps: Since the Fe²⁺ concentration is greater than 10 g / L, the total flow rate of the aeration components is set to 1.8 m³ / h to provide sufficient oxygen; the pore size of the acid-resistant microbubble aeration head is 80 μm; b) Stirring step: The anchor-turbine composite agitator of the stirring assembly operates at a speed of 550 r / min rpm to ensure full contact between the high concentration of Fe²⁺ and oxygen bubbles.

[0031] c) Applying the electrostatic field: Based on the initial pH value (2.2, less than 2.5), the initial voltage of the high-voltage electrostatic generator is set to 18kV. The electrode plate spacing is set to 1.8 meters.

[0032] d) Monitoring and Control Procedures: The online zeta potential meter detected an initial potential of -15mV. The controller dynamically adjusted the electrostatic field strength, ultimately stabilizing the zeta potential of the oxygen bubble within the target range of -38mV.

[0033] e) pH control: The pH value of the reaction process is slowly increased and stabilized at 2.8±0.1 by automatically adding a neutralizing agent.

[0034] Technical effects: Despite the high initial Fe²⁺ concentration, the reaction is completed within 4 hours using this method. Compared to traditional processes that require more than 10 hours, this represents an efficiency improvement of over 60%. Oxygen utilization is significantly enhanced, and consumption is reduced by approximately 55% compared to traditional methods.

[0035] Example 3 This embodiment aims to demonstrate the effectiveness of the method at low iron concentrations. In an 80 m³ leaching tank, the initial Fe²⁺ concentration of the leachate was 3 g / L, and the initial pH was 3.4.

[0036] The specific implementation process is as follows: a) Aeration steps: Based on the low Fe²⁺ concentration (3g / L<10g / L), a low aeration flow rate of 0.6 m³ / h is set to meet the reaction requirements while saving gas; the pore size of the acid-resistant microbubble aerator head is 50μm; b) Stirring step: The stirring paddle runs at a speed of 480 r / min rpm to avoid excessive stirring that would increase energy consumption.

[0037] c) Applying the electrostatic field: Based on the initial pH value (3.4, greater than 3.0), the initial voltage is set to 11kV.

[0038] d) Monitoring and control steps: The system automatically and precisely controls the zeta potential of the oxygen bubble to around -26mV.

[0039] e) pH control: The pH was kept stable at 3.3±0.1 throughout the process.

[0040] Technical effects: The reaction is completed in 2 hours, much faster than the traditional process which takes about 6 hours. This example demonstrates that even under low load, the present invention can significantly improve production efficiency (by about 66%) and save about 45% of oxygen consumption by optimizing bubble surface properties and reaction kinetics.

[0041] Example 4 This embodiment focuses on demonstrating the synergistic effect of the method with optimized equipment configuration. The same 100 m³ leaching tank and composition (Fe²⁺ 5 g / L, pH 3.0) as in Example 1 were used, but with particular emphasis on precise control of equipment parameters.

[0042] The specific implementation process is as follows: The implementation steps of this embodiment are basically the same as those of Embodiment 1, but it has the following key optimization features: The aeration heads are arranged in a ring pattern, evenly distributed at the center and edges of the tank bottom, to ensure no dead zones in aeration. The pore size of the acid-resistant microbubble aeration heads is 75μm.

[0043] Stirring steps: The stirring paddle runs at a speed of 450 r / min.

[0044] The tilt angle of the electrode plates was set to 80°, and the spacing was calculated to be 1.15 meters to achieve more uniform electric field.

[0045] The controller is more sensitive to zeta potential, strictly controlling potential fluctuations within an extremely narrow range of -30mV ± 2mV.

[0046] pH control: The pH was kept stable at 3.5±0.1 throughout the process.

[0047] Technical effects: Through the aforementioned refined parameter control, this embodiment completed the iron deposition process within 3 hours, while achieving a minimum reduction of 60% in oxygen consumption. This demonstrates that, with highly optimized parameters, the potential of the method of this invention to improve oxygen utilization and shorten the reaction cycle can be maximized, resulting in optimal overall technical and economic indicators.

[0048] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for improving the oxygen utilization rate during oxygenation and stirring in a zinc leaching and iron deposition process, characterized in that, The method includes the following steps: a) In the leaching tank, oxygen is introduced into the leaching solution containing ferrous iron through an aeration assembly head located at the bottom of the tank to generate initial oxygen bubbles; b) The leachate is stirred by a stirring component located above the aeration component to disperse oxygen bubbles; c) By applying a high-voltage electrostatic field to at least one pair of electrode plates immersed in the leachate, the electrode plates being insulated from the tank wall and inclined; d) Monitor the surface zeta potential of the oxygen bubble in real time using an online zeta potential meter; e) Based on the zeta potential value monitored in step d), the intensity of the high voltage electrostatic field mentioned in step c) is dynamically adjusted by the controller to stabilize the surface zeta potential of the oxygen bubble within the target range of -40mV to -25mV. During the entire process of stirring, aeration, and applying an electrostatic field, the pH value of the leachate is controlled to be maintained at 2.5~3.5 to promote the oxidation reaction of ferrous ions.

2. The method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process according to claim 1, characterized in that, In step a), the aeration assembly includes several sets of acid-resistant microbubble aeration heads, which are evenly arranged along the bottom of the leaching tank; the pore size of the acid-resistant microbubble aeration heads is 50~100μm.

3. The method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process according to claim 1, characterized in that, In step c), the spacing of the electrode plates is set according to the diameter of the leaching tank to ensure that the high-voltage electrostatic field can uniformly cover the leaching liquid area.

4. The method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process according to claim 1, characterized in that, The high-voltage electrostatic field is generated by a high-voltage electrostatic generator through a titanium-coated acid-resistant electrode plate.

5. The method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process according to claim 2, characterized in that, The mixing assembly includes a corrosion-resistant mixing motor, a duplex stainless steel mixing shaft, and an anchor-turbine composite mixing blade, with the mixing blade located above the aeration head.

6. The method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process according to claim 1, characterized in that, The aeration flow rate of the acid-resistant microbubble aerator head is adjusted according to the initial Fe²⁺ concentration in the leachate: when the Fe²⁺ concentration is >10g / L, the aeration flow rate is 1.2~2.0m³ / h; when the Fe²⁺ concentration is <10g / L, the aeration flow rate is 0.5~1.2m³ / h.

7. The method for improving the oxygen utilization rate of oxygenation and stirring in the zinc leaching and iron deposition process according to claim 1, characterized in that, In step c), when the high-voltage electrostatic field is started, the initial voltage is adjusted according to the initial pH value of the leachate: when the initial pH value is less than 2.5, the initial voltage is 15~20kV; when the initial pH value is greater than 3.0, the initial voltage is 10~15kV; wherein, the initial pH value is the pH value measured before or at the beginning of step a).

8. A method for improving the oxygen utilization rate of oxygenation and stirring in a zinc leaching and iron deposition process according to any one of claims 1 to 7, characterized in that, The initial Fe²⁺ concentration in the leachate is 3~8 g / L, and the initial pH is 1.5~3.5.