Mercury-containing acid mud efficient recovery method and device based on difference frequency resonance coupling

Abstract

The invention relates to a mercury-containing acid mud efficient recovery method and device based on difference frequency resonance coupling. The high-efficiency mercury-containing acid mud recovery method based on difference frequency resonance coupling comprises the following steps: step 1, acid mud pretreatment: crushing, screening and drying mercury-containing acid mud; 2, coupled field leaching is conducted, specifically, a product in the step 1 is conveyed into a reaction kettle, stirring is conducted after an oxidizing agent is added, an acid mud turbid liquid is obtained, an oxidation-reduction reaction is conducted through catalysis of a difference frequency resonance coupled field formed by two frequency-adjustable ultrasonic waves, and the difference frequency adjusting range delta f is 6-10 kHz; step 3, carrying out solid-liquid separation; leaching liquid containing mercury and selenium is obtained. According to the scheme provided by the invention, the standing wave effect can be formed through the difference frequency, and the crushing efficiency of the cavitation bubbles is improved, so that the oxidation reaction speed of the mercury-containing acid mud turbid liquid is improved; secondly, through the adjustable frequency, the situation that the ultrasonic frequency is not matched with the mercury ion concentration and the turbid liquid temperature, and consequently ultrasonic energy waste is caused is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hazardous waste resource processing, in particular to a high-efficiency mercury-containing acid sludge recovery method and device based on difference frequency resonance coupling. BACKGROUND

[0002] In related technologies, in the process of smelting flue gas for acid production of non-ferrous metals such as copper, lead and zinc, the smelting flue gas usually passes through a high-temperature electric dust collector and a purification process. In the purification process, a dilute acid circulation washing process is generally used to wash the impurities carried by the flue gas into the solution, and at the same time the temperature of the flue gas is reduced to normal temperature. Most of the impurities washed down are insoluble in the liquid and precipitate, and the liquid is filtered to obtain acid sludge. The acid sludge usually contains various valuable metals such as selenium and mercury, as well as toxic and harmful substances. Mercury is toxic, but it is also indispensable in chemical industry, instrument manufacturing and other aspects, and proper treatment of mercury is crucial for environmental protection; selenium is an important raw material for semiconductor materials and functional materials, and has a wide range of applications in electronics, chemical industry, medicine and other fields.

[0003] At present, the main methods for treating acid sludge include fire roasting, oxygen pressure leaching and conventional acid leaching method. The method for treating mercury-containing acid sludge usually adopts single-frequency ultrasonic wave to realize leaching, but it has problems such as uneven distribution of cavitation effect, slow breaking speed of cavitation bubbles, low oxidation reaction speed, etc. It also has problems such as constant output of ultrasonic wave energy, low energy utilization rate, waste of ultrasonic wave energy, etc. SUMMARY

[0004] To solve or partially solve the problems in the related art, the present application provides a high-efficiency mercury-containing acid sludge recovery method and device based on difference frequency resonance coupling. The high-efficiency mercury-containing acid sludge recovery method and device based on difference frequency resonance coupling can form a standing wave effect through difference frequency, improve the breaking efficiency of cavitation bubbles, and thus improve the oxidation reaction speed of mercury-containing acid sludge suspension. Secondly, by adjusting the frequency, the ultrasonic generator can catalyze the oxidation reaction according to the optimal frequency at different mercury ion concentrations and suspension temperatures, avoiding the mismatch between the ultrasonic frequency and the mercury ion concentration and the suspension temperature, and causing waste of ultrasonic energy.

[0005] The present application provides a high-efficiency mercury-containing acid sludge recovery method and device based on difference frequency resonance coupling, which comprises the following steps: step 1: acid sludge pretreatment: crushing, screening and drying the mercury-containing acid sludge; Step 2: Coupling field leaching: the product in step 1 is transported into a reaction kettle, an oxidizing agent is added and stirred to obtain an acid sludge suspension, and then a difference frequency resonance coupling field formed by two adjustable frequency ultrasonic waves is used to catalyze the oxidation-reduction reaction, and the difference frequency adjustment range is Δf=6-10 kHz. Step 3: solid-liquid separation; the material produced by the redox reaction is subjected to solid-liquid separation by a vacuum filtration device, and the obtained filtrate is the leaching solution containing mercury selenium; the leaching solution containing mercury selenium is subjected to further purification and purification treatment, and the mercury selenium is separated by reduction, thereby obtaining a selenium leaching solution and a mercury leaching solution.

[0006] Optionally, in some embodiments, the mercury-containing acid sludge in step 1 is crushed by an air flow crusher. In step 2, the upper end of the reaction kettle is provided with a frequency-adjustable ultrasonic generator I and an ultrasonic generator II; both the ultrasonic generator I and the ultrasonic generator II are controlled and adjusted in frequency by a PLC controller, and the frequency difference between the two is in the range of 6-10 kHz; the reaction kettle detects the mercury ion concentration data by an integrated mercury ion sensor and feeds back to the PLC controller; the PLC controller controls the frequency adjustment of the ultrasonic generator I; the mercury ion concentration is directly proportional to the frequency of the ultrasonic generator I; the reaction kettle detects the temperature of the acid slurry suspension by a temperature sensor array and feeds back to the PLC controller; the PLC controller controls the frequency adjustment of the ultrasonic generator II; the temperature of the acid slurry suspension is inversely proportional to the frequency of the ultrasonic generator II. The reaction kettle is provided with a stirrer and a flow guide cylinder inside. Optionally, in some embodiments, the solid-liquid separation in step 3 is performed by a vacuum filtration device.

[0007] The inclination angle of the spiral blade of the stirrer is set to 15°; the flow guide cylinder is installed in the reaction kettle through a support rod, and the upper end of the flow guide cylinder is outwardly inclined, forming a conical cylinder with a large upper end and a small lower end.

[0008] Optionally, in some embodiments, the ultrasonic generator I and the ultrasonic generator II are installed on the reaction kettle through an ultrasonic energy coupler; the matching coefficient of the impedance matcher of the ultrasonic energy coupler is greater than or equal to 0.9; the compensation amount of the attenuation compensator is ±5 dB; and the energy transmission pipeline is Φ150 mm.

[0009] The technical scheme provided in the present application can include the following beneficial effects: The mercury-containing acid slurry efficient recovery method and device based on difference frequency resonance coupling can form a standing wave effect through difference frequency, improve the collapse efficiency of cavitation bubbles, and further improve the oxidation reaction speed of the mercury-containing acid slurry suspension; secondly, through adjustable frequency, the ultrasonic generator can catalyze the oxidation reaction according to the optimal frequency at different mercury ion concentrations and suspension temperatures, avoiding the mismatch between the ultrasonic frequency and the mercury ion concentration and the suspension temperature, thereby avoiding the waste of ultrasonic energy.

[0010] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0011] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures, and in which:

[0012] Figure 1 is a structural schematic diagram of a mercury-containing acid sludge efficient recovery method and device based on difference frequency resonant coupling shown in an embodiment of the present application; Figure 2 is a structural schematic diagram of a reaction kettle 1 shown in an embodiment of the present application; Figure 3 is a sectional view of the reaction kettle 1 shown in an embodiment of the present application.

[0013] The drawing mark is: reaction kettle 1, ultrasonic generator I 2, ultrasonic generator II 3, plc controller 4, integrated mercury ion sensor 5, temperature sensor array 6, stirrer 7, flow guide cylinder 8, support rod 9, ultrasonic wave energy coupler 11. DETAILED DESCRIPTION

[0014] Embodiments of the present application will be described in more detail by making reference to the drawings. Although embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application is more thorough and complete, and the scope of the present application is fully conveyed to those skilled in the art.

[0015] It should be understood that although the present application can employ the terms "first", "second" and the like to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the present application. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0016] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0017] Unless otherwise defined, the terms "mounting", "connected", "connecting", "fixed", and "fixedly connected" are to be construed as broad terms, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be internal connection of two elements, or interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0018] To solve the above problems, the embodiment of the present application provides a kind of based on difference frequency resonant coupling's mercury-containing acid mud high-efficiency recovery method and device, can form standing wave effect by difference frequency, improve the collapse efficiency of cavitation bubble, and then improve the oxidation reaction speed of mercury-containing acid mud suspension liquid;Secondly, through adjustable frequency, so that ultrasonic generator catalyzes oxidation reaction according to the best frequency at different mercury ion concentration and suspension liquid temperature, avoid ultrasonic frequency and mercury ion concentration and suspension liquid temperature mismatch, cause ultrasonic energy waste.

[0019] The technical solutions of the embodiments of the present application are described in detail below with reference to the drawings.

[0020] Figure 1 It is a kind of based on difference frequency resonant coupling's mercury-containing acid mud high-efficiency recovery method and device structure schematic diagram shown in the embodiment of the present application.

[0021] Referring to Figure 1 The embodiment 1 shows a kind of based on difference frequency resonant coupling's mercury-containing acid mud high-efficiency recovery method, which includes the following steps: step 1: acid mud pretreatment: acid mud containing mercury is crushed, screened, dried;Crushing and screening to D90≤45 μm, while drying under inert atmosphere, temperature is 80℃±2℃.

[0022] Step 2: coupling field leaching: the product in step 1 is transported to the reaction kettle 1, and an acid mud suspension is obtained after stirring after adding an oxidizing agent, the mercury-containing acid mud and the oxidizing agent liquid ratio is 1:2 (g / mL), the oxidizing agent uses a combination of hydrochloric acid concentration 2.0 mol / L, H2O2 concentration 0.2 mol / L, FeCl3 concentration 0.1 mol / L); and a redox reaction is carried out by catalysis through the difference frequency resonance coupling field formed by two adjustable frequency ultrasonic waves, and the difference frequency adjustment range is Δf=6-10 kHz; the difference frequency resonance coupling field formed by two ultrasonic waves forms a standing wave superposition effect, so that the cavitation bubbles in the mercury-containing acid mud suspension are quickly broken, the duty cycle reaches 80%, the reaction temperature is 45℃±3℃, the oxygen partial pressure is 0.15 MPa, the reaction time is 1h, and pH=2.5-3.5; the standing wave superposition effect can effectively improve the breaking efficiency of the cavitation bubbles, and further improve the oxidation reaction efficiency; secondly, the two ultrasonic waves are symmetrically installed, so that the energy generated by the ultrasonic waves is uniformly diffused in the reaction kettle, further improving the breaking efficiency of the cavitation bubbles.

[0023] Step 3: solid-liquid separation; the material produced by the redox reaction is subjected to solid-liquid separation by a vacuum filtration device, and the filtrate obtained is the leaching solution containing mercury and selenium. The leaching solution containing mercury and selenium is further purified and treated, and the mercury and selenium are separated by reduction, to obtain a selenium leaching solution and a mercury leaching solution.

[0024] The mercury-containing acid mud in step 1 is crushed by an air flow crusher; the pressure is 0.6 MPa; in step 2, the upper end of the reaction kettle 1 is provided with a frequency-adjustable ultrasonic generator I2 and an ultrasonic generator II3, both of which are controlled and adjusted in frequency by a plc controller 4, and the frequency difference between the two is in the range of 6-10 kHz; the reaction kettle 1 detects the mercury ion concentration data through an integrated mercury ion sensor 5 and feeds back to the plc controller 5, which controls the frequency adjustment of the ultrasonic generator I2, and the mercury ion concentration is proportional to the frequency of the ultrasonic generator I2; the reaction kettle 1 detects the temperature of the acid mud suspension through a temperature sensor array 6 and feeds back to the plc controller 5, which controls the frequency adjustment of the ultrasonic generator II3, and the temperature of the acid mud suspension is inversely proportional to the frequency of the ultrasonic generator II3; the reaction kettle 1 is provided with a stirrer 7 and an internal flow guide cylinder 8; step 3 is subjected to solid-liquid separation by a vacuum filtration device 10.

[0025] When the mercury-containing acid sludge and oxidant are added into the reaction kettle 1 at a ratio of 1:2 (g / mL), a mercury-containing acid sludge suspension is formed by the stirrer 7, and then the ultrasonic generator I 2 and the ultrasonic generator II 3 are preheated, and the acid sludge suspension is heated to 40°C. The initial frequency of the ultrasonic generator I 2 is 28 kHz, and the initial frequency of the ultrasonic generator II 3 is 37 kHz, and the frequency difference is 9 kHz. Under the differential frequency resonance coupling field formed by the ultrasonic generator I 2 and the ultrasonic generator II 3, the mercury-containing acid sludge suspension in the reaction kettle 1 undergoes an oxidation reaction.

[0026] After the oxidation reaction starts, the integrated mercury ion sensor 5 detects the mercury ion concentration data. After the mercury ion concentration increases, the frequency of the ultrasonic generator I 2 is increased by the plc controller 5, and the frequency of the ultrasonic generator II 3 is increased synchronously according to the corresponding frequency difference. When the frequency of the ultrasonic generator II 3 is increased to 58 kHz, the frequency of the ultrasonic generator II 3 is stopped increasing. If the mercury ion concentration continues to increase, the frequency of the ultrasonic generator I 2 is increased, and the frequency difference between the ultrasonic generator I 2 and the ultrasonic generator II 3 is reduced to 6 kHz. Then the ultrasonic generator I 2 is kept at 52 kHz and the ultrasonic generator II 3 is kept at 58 kHz for the oxidation reaction.

[0027] In the above frequency adjustment process, according to the initial temperature detected by the temperature sensing array 6, which is 40°C, before the temperature of the suspension rises to 45°C after the ultrasonic generator I 2 and the ultrasonic generator II 3 are turned on, the frequency difference between the ultrasonic generator I 2 and the ultrasonic generator II 3 can be increased. When the maximum frequency difference reaches 12 kHz, it will not be increased any more. When the temperature of the suspension is higher than 45°C, the speed of the ultrasonic generator II 3 needs to be slowed down to reduce the frequency difference, and when the minimum frequency difference reaches 6 kHz, it will not be reduced any more. In the process of adjusting the frequency of the ultrasonic generator I 2 and the ultrasonic generator II 3, different ultrasonic frequencies corresponding to different mercury ion concentrations can effectively improve the cavitation bubble collapse efficiency, thereby improving the oxidation reaction speed and avoiding waste of ultrasonic energy due to excessively high ultrasonic frequency. By changing the temperature, the frequency difference is reduced, further avoiding the ultrasonic generator II 3 from increasing the frequency too fast and wasting ultrasonic energy.

[0028] The helical blade of the stirrer 7 is inclined at an angle of 15°, so that during rotation of the stirrer 7, the helical blade generates an upward lifting force on the suspension. The flow guide cylinder 8 is installed in the reaction kettle 1 by the support rod 9, and the upper end of the flow guide cylinder 8 is inclined outward, forming a conical cylinder with a large upper end and a small lower end. After the suspension is lifted upward, the liquid flows upward along the flow guide cylinder 8, and then flows down from the wall of the reaction kettle 1, so that the suspension can rotate horizontally and also circulate vertically, improving the oxidation reaction efficiency of the suspension.

[0029] The ultrasonic generator I 2 and the ultrasonic generator II 3 are installed on the reaction kettle 1 through the ultrasonic energy coupler 11, the matching coefficient of the impedance matcher of the ultrasonic energy coupler 11 is greater than or equal to 0.9, the compensation amount of the attenuation compensator is ±5dB, and the energy transmission pipeline is Φ150mm; so that the ultrasonic energy generated by the ultrasonic generator I 2 and the ultrasonic generator II 3 is more stable and accurate, and the frequency modulation accuracy of the ultrasonic generator I 2 and the ultrasonic generator II 3 is effectively improved.

[0030] The above has described the embodiments of the present application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications or improvements to the technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A method and apparatus for efficient recovery of mercury-containing acid sludge based on differential frequency resonance coupling, characterized in that: The efficient recovery method for mercury-containing acid sludge based on difference frequency resonance coupling includes: Step 1: Pretreatment of acid sludge: Crush, sieve, and dry the mercury-containing acid sludge; Step 2: Coupled field leaching: The product from step 1 is transported to the reactor (1), an oxidant is added and stirred to obtain an acid mud suspension, and then the oxidation-reduction reaction is catalyzed by the difference frequency resonance coupled field formed by two tunable ultrasonic waves, and the difference frequency adjustment range Δf = 6-10kHz. Step 3: Solid-liquid separation; The material produced by the oxidation-reduction reaction is subjected to solid-liquid separation by a vacuum filtration device. The obtained filtrate is a leachate containing mercury and selenium. The leachate containing mercury and selenium is further purified and refined by selenium-mercury reduction separation to obtain selenium leachate and mercury leachate.

2. The device for efficient recovery of mercury-containing acid sludge based on dual-frequency resonant coupling according to claim 1, characterized in that: In step 1, the mercury-containing acid sludge is pulverized by an air jet mill; In step 2, an adjustable ultrasonic generator I (2) and an ultrasonic generator II (3) are installed at the upper end of the reactor (1). The ultrasonic generator I (2) and the ultrasonic generator II (3) are both controlled by a PLC controller (4) to adjust their frequencies, and the frequency difference between them is 6-10kHz. The reactor (1) detects mercury ion concentration data through an integrated mercury ion sensor (5) and feeds it back to the PLC controller (5). The PLC controller (5) controls the ultrasonic generator I (2) to adjust its frequency. The mercury ion concentration is directly proportional to the frequency of the ultrasonic generator I (2). The reactor (1) detects the temperature of the acid sludge suspension through a temperature sensor array (6) and feeds it back to the PLC controller (5). The PLC controller (5) controls the ultrasonic generator II (3) to adjust its frequency. The temperature of the acid sludge suspension is inversely proportional to the frequency of the ultrasonic generator II (3). The reactor (1) is equipped with a stirrer (7) and has a flow guide tube (8) inside. Step 3 involves solid-liquid separation using a vacuum filtration device.

3. The high-efficiency recovery device for mercury-containing acid sludge based on dual-frequency resonant coupling according to claim 2, characterized in that: The stirrer (7) has a spiral blade tilt angle of 15°. The guide tube (8) is installed in the reactor (1) through the support rod (9). The upper end of the guide tube (8) is tilted outward and is a conical cylinder with a larger upper end and a smaller lower end.

4. The high-efficiency recovery device for mercury-containing acid sludge based on dual-frequency resonant coupling according to claim 2, characterized in that: The ultrasonic generator I (2) and ultrasonic generator II (3) are installed on the reactor (1) through an ultrasonic energy coupler (11). The matching coefficient of the impedance matching device is ≥0.9, the compensation amount of the attenuation compensator is ±5dB, and the energy transmission pipe is Φ150mm.

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