Solid-liquid separation device for waste sulfuric acid

Abstract

The invention provides a waste sulfuric acid solid-liquid separation device which comprises a solid-liquid separation tank, a waste acid receiving barrel, a central rotating shaft and an annular overflow groove, the solid-liquid separation tank is used for containing waste sulfuric acid for settling separation, and the waste acid receiving barrel is arranged in the center of the top of the solid-liquid separation tank and used for guiding the waste sulfuric acid to enter the solid-liquid separation tank; the central rotating shaft is vertically mounted in the solid-liquid separation tank, the top of the central rotating shaft penetrates through the solid-liquid separation tank to be connected with a driving motor, the central rotating shaft and the waste acid receiving barrel are coaxially arranged, the annular overflow tank is arranged around the top edge of the solid-liquid separation tank, and the annular overflow tank is arranged in the solid-liquid separation tank. The annular overflow groove is communicated with the solid-liquid separation groove, and when the liquid level in the solid-liquid separation groove reaches a set height, supernate automatically overflows from the groove along the annular overflow groove. Through a mode of combining gravity settling and mechanical scraping, solid impurities such as chlorine dust in the waste sulfuric acid are efficiently removed, resource utilization of the sulfuric acid is realized, and the waste acid treatment cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of waste liquid treatment and resource utilization, and particularly relates to a solid-liquid separation device for waste sulfuric acid treatment, which is used for the sedimentation separation and reuse of waste sulfuric acid containing impurities. Background Art

[0002] At present, a large amount of waste sulfuric acid containing impurities is generated during the production of chlorine gas in magnesium electrolysis. Such waste sulfuric acid often contains precipitable solid impurities, such as chloride dust, chlorine dust, and solid particles such as magnesium oxide and magnesium hydroxide. As the use time goes by, the sulfuric acid concentration in the waste sulfuric acid continuously decreases and cannot meet the requirements of cyclic use; at the same time, the content of chlorine dust impurities in the waste sulfuric acid gradually increases, resulting in complex waste acid properties and being difficult to directly reuse.

[0003] Traditional waste acid treatment methods mainly include chemical precipitation, neutralization, filtration, evaporation and concentration, etc., but there are problems such as many treatment steps, high cost, complex operation, easy blockage or large wear of equipment. For example, the method of neutralizing waste sulfuric acid into sludge can remove certain solid impurities, but it will produce a large amount of sulfate-containing waste residue, increasing the subsequent hazardous waste treatment cost; conventional centrifugation or filtration methods have limited removal effects on colloids and fine particles, and the filter cloth is easy to block and requires frequent maintenance. Therefore, there is an urgent need in the prior art for a solid-liquid separation device that can not only efficiently remove solid impurities in waste sulfuric acid but also realize the reuse of sulfuric acid resources. Summary of the Invention

[0004] In view of this, the present invention aims to provide a solid-liquid separation device for waste sulfuric acid to solve the problems in the prior art such as low impurity removal efficiency, high treatment cost, low resource recovery rate, and high environmental pollution risk during the treatment of industrial waste sulfuric acid.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A solid-liquid separation device for waste sulfuric acid, comprising a solid-liquid separation tank, a waste acid receiving barrel, a central rotating shaft, and an annular overflow tank. The solid-liquid separation tank is used to accommodate waste sulfuric acid for sedimentation separation. The waste acid receiving barrel is arranged at the central position on the top of the solid-liquid separation tank and is used to guide waste sulfuric acid into the solid-liquid separation tank. The central rotating shaft is vertically installed inside the solid-liquid separation tank. The top of the central rotating shaft passes through the solid-liquid separation tank and is connected to a driving motor. The central rotating shaft is coaxially arranged with the waste acid receiving barrel. The annular overflow tank is arranged around the top edge of the solid-liquid separation tank and is communicated with the solid-liquid separation tank. When the liquid level in the solid-liquid separation tank reaches the set height, the supernatant automatically overflows from the solid-liquid separation tank along the annular overflow tank.

[0007] Furthermore, the waste acid receiving tank is arranged in a cylindrical structure. A waste sulfuric acid inlet is provided at the top of the waste acid receiving tank, and waste sulfuric acid is added into the waste acid receiving tank through the waste sulfuric acid inlet. The bottom of the waste acid receiving tank is communicated with the inside of the solid-liquid separation tank.

[0008] Furthermore, a rotating rake frame is provided at the bottom of the central rotating shaft. The rotating rake frame at least partially covers the bottom of the solid-liquid separation tank, and the rotating rake frame rotates to scrape the solids at the bottom of the solid-liquid separation tank.

[0009] Furthermore, the rotating rake frame includes a plurality of radially arranged rake arms, and a plurality of scraping plates are provided on each rake arm, and the scraping plates extend downward.

[0010] Furthermore, the scraping plates are arranged at multiple angles at the end of the rotating rake frame.

[0011] Furthermore, a discharge hopper is arranged at the center or an eccentric position on one side of the bottom of the solid-liquid separation tank. The discharge hopper is communicated with the inside of the tank body of the solid-liquid separation tank and is used for collecting the solid materials that are scraped up.

[0012] Furthermore, the lower end of the discharge hopper is connected to a screw conveyor, which is used for continuously conveying the scraped solid materials to a storage container or a conveying pipeline outside the tank.

[0013] Furthermore, the screw conveyor is arranged in an upwardly inclined structure, and the conveying end of the screw conveyor is higher than the liquid outlet of the solid-liquid separation tank.

[0014] Furthermore, the top of the annular overflow tank forms the top cover of the solid-liquid separation tank. The middle bottom surface of the annular overflow tank is higher than the edge bottom surface of the annular overflow tank. A liquid outlet is provided on the middle bottom surface of the annular overflow tank, and an overflow port is provided on the outer side surface of the annular overflow tank. The supernatant liquid inside the solid-liquid separation tank enters the inside of the annular overflow tank through the liquid outlet, and then the liquid inside the annular overflow tank is discharged to the outside of the solid-liquid separation device through the overflow port.

[0015] Furthermore, a pressure relief port is also provided at the top of the solid-liquid separation tank, and the pressure relief port is communicated with the inside of the solid-liquid separation tank.

[0016] Compared with the prior art, the industrial waste sulfuric acid solid-liquid separation device of the present invention has the following advantages:

[0017] ① Structurally enclosed to prevent volatilization and leakage: This device adopts a fully enclosed design, avoiding the evaporation and loss of sulfuric acid and the emission of harmful gases during the waste acid treatment process. Through physical separation methods without the need for chemical agents, it reduces environmental pollution and safety risks.

[0018] ②High-efficiency impurity removal and resource utilization: Through the scheme of gravity sedimentation + mechanical scraper separation, this device can effectively remove chlorine dust and other solid impurities in waste sulfuric acid, with minimal loss of the supernatant concentration. The treated waste acid can meet the reuse standard and can be recycled for production, realizing resource recycling.

[0019] ③Reduce treatment costs: Compared with traditional neutralization and waste residue treatment, this invention requires no or significantly reduces the use of chemical agents, reducing the amount of waste residue generated; the stable solid-liquid separation process and continuous slag discharge function reduce labor and maintenance costs; the overall treatment efficiency is high, and the comprehensive economic benefits are significantly improved.

[0020] ④Stable operation and convenient maintenance: The device has a simple and compact structure, high degree of automation, and can operate continuously and stably. The scraper and screw conveyor structures are easy to maintain and clean, without vulnerable parts, greatly reducing the maintenance workload. The overall equipment is suitable for long-term operation in industrial sites.

[0021] ⑤Wide application range: This device can be applied to the treatment of various waste sulfuric acids in industries such as magnesium electrolysis, pickling, and smelting, and has general popularization value. A solid-liquid separation device for combined operation of sealed gravity sedimentation and mechanical scraping realizes the effective separation of solid impurities such as chlorine dust and magnesium salts in waste sulfuric acid, and clarifies and purifies the waste acid solution. Brief Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the waste sulfuric acid solid-liquid separation device described in the embodiment of the present invention;

[0023] Figure 2 is a perspective view of the solid-liquid separation tank described in the embodiment of the present invention;

[0024] Figure 3 is Figure 2 the A-A cross-sectional view shown.

[0025] Description of the reference numerals:

[0026] 1 - driving motor; 2 - pressure relief port; 3 - annular overflow tank; 31 - liquid outlet; 4 - waste acid receiving barrel; 41 - waste sulfuric acid inlet; 5 - solid-liquid separation tank; 51 - solid discharge port; 6 - central rotating shaft; 7 - rotating rake frame; 71 - scraper; 72 - rake arm; 8 - waste acid feed port; 9 - overflow port; 10 - slag outlet; 11 - screw conveyor; 12 - support frame; 13 - discharge hopper; 14 - lower support. Detailed Embodiments

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the accompanying drawings.

[0028] As Figures 1 - 3As shown in the figure, an industrial waste sulfuric acid solid-liquid separation device mainly includes the following parts:

[0029] (1) Closed solid-liquid separation tank 5: It is used to hold waste sulfuric acid for sedimentation separation. Specifically, the solid-liquid separation tank 5 includes a tank body, the top cover of the tank body can be sealed, the space inside the tank body is isolated from light, the bottom of the tank body can be conical or flat-bottomed, and a solid discharge port 51 is provided at the center or eccentric position of the bottom of the tank body. The opening and closing of the solid discharge port 51 can be controlled to ensure that solid particles are easy to concentrate and discharge.

[0030] (2) Waste acid receiving cylinder 4: It is arranged at the central position on the top of the solid-liquid separation tank 5 and is used to guide waste sulfuric acid into the solid-liquid separation tank 5. The waste acid receiving cylinder 4 is arranged in a cylindrical structure. A waste sulfuric acid inlet 41 is provided at the top of the waste acid receiving cylinder 4. Waste sulfuric acid is added into the waste acid receiving cylinder 4 through the waste sulfuric acid inlet 41. The bottom of the waste acid receiving cylinder 4 is communicated with the inside of the solid-liquid separation tank 5. The cylinder wall of the waste acid receiving cylinder 4 plays a guiding role in the addition of waste sulfuric acid, ensuring that waste sulfuric acid enters the inside of the solid-liquid separation tank 5, and at the same time preventing waste sulfuric acid from splashing during the addition process and promoting the uniform distribution of waste acid.

[0031] (3) Central rotating shaft 6: It is vertically installed inside the solid-liquid separation tank 5. The central rotating shaft 6 penetrates from the top to the bottom of the solid-liquid separation tank 5. The top of the central rotating shaft 6 passes through the solid-liquid separation tank 5 and is connected to the driving motor 1. The central rotating shaft 6 is coaxially arranged with the waste acid receiving cylinder 4 to avoid interference between the rotation of the central rotating shaft 6 and the cylinder wall of the waste acid receiving cylinder 4. At the same time, the central rotating shaft 6 can also play a guiding role in the waste acid added into the waste acid receiving cylinder 4.

[0032] A rotating rake frame 7 is arranged at the bottom of the central rotating shaft 6. The rotating rake frame 7 at least partially covers the bottom of the solid-liquid separation tank 5. The rotating rake frame 7 rotates to scrape the solids at the bottom of the tank. Further, the rotating rake frame 7 includes multiple radially arranged rake arms 72. Multiple scraping plates 71 are arranged on each rake arm 72. The scraping plates 71 extend downward. When the central rotating shaft 6 rotates, it drives the rotating rake frame 7 to rotate slowly, and then drives the scraping plates at the lower part of the rake arms 72 to move along the bottom of the tank at a low speed to scrape the solids at the bottom of the solid-liquid separation tank 5.

[0033] Further, the scraping plates 71 are arranged at multiple angles at the end of the rotating rake frame 7 and are used to scrape the solid particles deposited at the bottom of the tank and push them towards the discharge hopper. A small gap is maintained between the scraping plates 71 and the bottom of the tank to tolerate a certain amount of wear.

[0034] (4) Discharge hopper 13: It is located at the central position or an eccentric position on one side of the bottom of the solid-liquid separation tank 5 and is communicated with the inside of the tank body of the solid-liquid separation tank 5. It is used to collect the solid materials that are scraped up. A screw conveyor 11 interface is provided at the lower end of the discharge hopper 13.

[0035] (5) Screw conveyor 11: Connected to the lower end of the discharge hopper 13, it is used to continuously convey the scraped solid materials to a storage container or a conveying pipeline outside the tank, ensuring the timely discharge of sediments.

[0036] Further, the screw conveyor 11 is arranged in an upwardly inclined structure, and the conveying end of the screw conveyor 11 is higher than the liquid outlet of the solid-liquid separation tank 5, preventing the liquid phase inside the solid-liquid separation tank 5 from being discharged through the screw conveyor. A slag discharge port 10 is provided at the end or near the end of the screw conveyor 11, and the slag discharge port 10 is connected to a solid-phase collection container for collecting the solid particles discharged from the solid-liquid separation tank 5.

[0037] Even further, a support frame 12 is provided at the end of the screw conveyor 11, and the support frame 12 is used to fix the end of the screw conveyor 11 at a set height.

[0038] (6) Annular overflow tank 3: Arranged around the top edge of the solid-liquid separation tank 5, the annular overflow tank 3 communicates with the solid-liquid separation tank 5. When the liquid level in the solid-liquid separation tank 5 reaches the set height, the supernatant automatically overflows from the tank along the annular overflow tank and is guided to a recovery tank or the next process. The overflow tank ensures a stable liquid level in the liquid discharge tank without overflowing.

[0039] Specifically, the annular overflow tank 3 is arranged in an inverted basin-like structure. The lower part of the annular overflow tank 3 is connected to the solid-liquid separation tank 5, the four sides of the annular overflow tank 3 abut against the top of the solid-liquid separation tank 5, the top of the annular overflow tank 3 forms the top cover of the solid-liquid separation tank 5, the middle bottom surface of the annular overflow tank 3 is higher than the edge bottom surface of the annular overflow tank 3. A liquid outlet 31 is provided on the middle bottom surface of the annular overflow tank 3, and an overflow port 9 is provided on the outer side surface of the annular overflow tank 3. The supernatant inside the solid-liquid separation tank 5 enters the inside of the annular overflow tank 3 through the liquid outlet 31, and then the liquid inside the annular overflow tank 3 is discharged outside the solid-liquid separation device through the overflow port 9.

[0040] Further, the top surface of the annular overflow tank 3 can be arranged as a flat surface or an arc-shaped structure.

[0041] (7) Other components: Also include a lower support 14, a seal, a liquid level control device, etc. The lower support 14 is arranged at the lower part of the solid-liquid separation tank 5 to stably support the solid-liquid separation tank and the rotating shaft system. The inner wall of the tank body of the solid-liquid separation tank 5 and the surfaces of the components are all treated with an acid-resistant material coating or plating. A liquid level detection and torque monitoring device can be equipped to automatically alarm or raise the rake when the rotation resistance of the scraper increases.

[0042] Further, a pressure relief port 2 is also provided at the top of the solid-liquid separation tank 5, and the pressure relief port 2 communicates with the inside of the solid-liquid separation tank 5 for relieving the pressure inside the solid-liquid separation tank 5.

[0043] In the resulting waste sulfuric acid solid-liquid separation device, the solid-liquid separation tank body is used to hold waste acid and perform solid-liquid separation, and a waste acid receiving cylinder is arranged at the top of the tank. The waste acid receiving cylinder is used to introduce waste sulfuric acid. The central rotating shaft penetrates from the top of the tank to the bottom of the tank and drives the rotating rake frame to rotate through a driving device. The scraper is installed on the periphery of the rake frame and is used to scrape the sediment at the bottom of the tank. The solids at the bottom of the tank are scraped to the bottom and conveyed to an external container through a screw conveyor. An annular overflow tank is arranged at the peripheral edge of the top of the tank and is used to collect the upper clear liquid. The entire separation tank is fixedly supported by a lower bracket.

[0044] The working process of the device is as follows:

[0045] Through the feed pipe, waste sulfuric acid is continuously injected into the waste acid receiving cylinder 4 of the closed separation tank; the particles suspended in the liquid settle by gravity under static or slow agitation in the tank and move towards the bottom of the tank.

[0046] The central rotating shaft 6 drives the rotating rake frame 7 to rotate at a constant low speed, and the solids suspended and settled gradually accumulate into a shallow sediment at the bottom of the tank. Multiple scrapers 71 on the rotating rake frame 7 push along the bottom of the tank and scrape the deposited solid particles towards the discharge hopper at the center of the bottom of the tank.

[0047] After the solid particles are scraped into the discharge hopper, they are continuously conveyed by a screw conveyor to the collection container outside the tank, and the continuous discharge of solids can be realized.

[0048] The treated supernatant automatically overflows to the external collection device through the annular overflow tank, and basically no solids are carried away during the liquid outflow process, improving the separation efficiency. After simple clarification, the supernatant can be recycled or further processed. Among them Figure 3 The direction indicated by the dotted line and arrow in the figure is the flow trajectory of the supernatant discharge.

[0049] The entire separation process is carried out in a closed state, avoiding environmental pollution caused by the volatilization of acid liquid and preventing safety problems caused by acid liquid leakage.

[0050] To prevent the excessive accumulation of solids in the tank from causing blockage, a rake frame lifting device is set. When the accumulation amount of solids at the bottom of the tank exceeds the set value, the rake frame is lifted as a whole through a mechanical system, so that the scraper is separated from the bottom of the tank by a certain distance, and part of the solids fall into the discharge hopper by themselves, thus avoiding system overload. In addition, liquid level and torque monitoring are set in the control system, and an alarm is given when an abnormal signal is detected.

[0051] Embodiment

[0052] A magnesium electrolysis production enterprise generates a large amount of waste sulfuric acid during the treatment of chlorine gas, containing about 5% solid impurities (mainly magnesium hydroxide, magnesium oxide, magnesium salt crystals, chlorine dust, etc.). If this waste acid is directly discharged, it needs to be handed over to a hazardous waste treatment unit for treatment, which is costly. By using the solid-liquid separation device of the present invention for treatment, the waste acid is evenly injected into the solid-liquid separation tank through the waste acid receiving hopper. After static sedimentation, as the rotating rake frame and scraper rotate, the solid particles gradually deposit and are scraped towards the discharge hopper and discharged by the screw conveyor. The supernatant after treatment is led out through the annular overflow tank. After concentration detection, the sulfuric acid concentration remains at about 93%, the chlorine content is significantly reduced, and the removal rate of solid impurities reaches more than 85%. The obtained liquid can be recycled into other production processes, reducing the newly purchased amount of sulfuric acid; the scraped solid impurities are treated as industrial waste residue after being pressed dry, reducing the hazardous waste incineration disposal volume by about 50%. According to the operation data of this enterprise, about 120 tons of waste acid can be treated annually, saving the waste acid procurement and waste residue treatment costs.

[0053] For the waste sulfuric acid generated by magnesium electrolysis, there are many types of impurities. In addition to chlorine dust, it also contains soluble salts such as zinc chloride and iron chloride. In the device of the present invention, the waste acid first undergoes static sedimentation in the solid-liquid separation tank, and most of the high-density insoluble impurities settle. The rotating rake frame cooperates with the scraper to scrape and discharge the lighter particles, and the screw conveyor ensures the smooth discharge of the waste residue. Under continuous operation conditions, the treatment time for each batch of this device is about 40 minutes, and the concentration of the discharged acid can be maintained above 93% of the original concentration, with good impurity removal effect. The equipment operates stably and is easy to maintain. Compared with the use of the traditional coagulation sedimentation process, this device saves about 20% of the floor area and more than 50% of the maintenance cost.

[0054] In summary, the industrial waste sulfuric acid solid-liquid separation device provided by the present invention realizes the efficient and clean separation and recycling of waste sulfuric acid through reasonable structural design and automatic control, highlighting innovation and practicability, and is applicable to industrial production practices in related fields.

[0055] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A waste sulfuric acid solid-liquid separation device, characterized in that, It includes a solid-liquid separation tank (5), a waste acid receiving barrel (4), a central rotating shaft (6) and an annular overflow tank (3). Among them, the solid-liquid separation tank (5) is used to hold waste sulfuric acid for sedimentation separation. The waste acid receiving barrel (4) is arranged at the central position on the top of the solid-liquid separation tank (5) and is used to guide waste sulfuric acid into the solid-liquid separation tank (5). The central rotating shaft (6) is vertically installed inside the solid-liquid separation tank (5). The top of the central rotating shaft (6) passes through the solid-liquid separation tank (5) and is connected to a driving motor (1). The central rotating shaft (6) is coaxially arranged with the waste acid receiving barrel (4). The annular overflow tank (3) is arranged around the top edge of the solid-liquid separation tank (5). The annular overflow tank (3) communicates with the solid-liquid separation tank (5). When the liquid level in the solid-liquid separation tank (5) reaches the set height, the supernatant automatically overflows from the solid-liquid separation tank (5) along the annular overflow tank (3).

2. The waste sulfuric acid solid-liquid separation device according to claim 1, wherein, The waste acid receiving barrel (4) is arranged in a cylindrical structure. The top of the waste acid receiving barrel (4) is provided with a waste sulfuric acid inlet (41). Waste sulfuric acid is added into the waste acid receiving barrel (4) through the waste sulfuric acid inlet (41). The bottom of the waste acid receiving barrel (4) communicates with the inside of the solid-liquid separation tank (5).

3. The waste sulfuric acid solid-liquid separation device according to claim 1, characterized in that, A rotating rake frame (7) is arranged at the bottom of the central rotating shaft (6). The rotating rake frame (7) at least partially covers the bottom of the solid-liquid separation tank (5). The rotating rake frame (7) rotates to scrape the solids at the bottom of the solid-liquid separation tank (5).

4. The waste sulfuric acid solid-liquid separation device according to claim 3, characterized in that, The rotating rake frame (7) includes multiple radially arranged rake arms (72). Multiple scraper plates (71) are arranged on each rake arm (72). The scraper plates (71) extend downward.

5. The waste sulfuric acid solid-liquid separation device according to claim 4, wherein, The scraper plates (71) are arranged at multiple angles at the end of the rotating rake frame (7).

6. The waste sulfuric acid solid-liquid separation device according to claim 1, wherein, A discharge hopper (13) is arranged at the center or an eccentric position on one side of the bottom of the solid-liquid separation tank (5). The discharge hopper (13) communicates with the inside of the tank body of the solid-liquid separation tank (5) and is used to collect the solid materials that are scraped up.

7. The waste sulfuric acid solid-liquid separation device according to claim 6, characterized in that, The lower end of the discharge hopper (13) is connected to a screw conveyor (11), which is used to continuously convey the scraped solid materials to a storage container or a conveying pipeline outside the tank.

8. The waste sulfuric acid solid-liquid separation device according to claim 7, wherein, The screw conveyor (11) is arranged in an upward-sloping structure, and the conveying end of the screw conveyor (11) is higher than the liquid outlet of the solid-liquid separation tank (5).

9. The waste sulfuric acid solid-liquid separation device according to claim 1, wherein, The top of the annular overflow tank (3) forms the top cover of the solid-liquid separation tank (5). The middle bottom surface of the annular overflow tank (3) is higher than the edge bottom surface of the annular overflow tank (3). A liquid outlet (31) is arranged on the middle bottom surface of the annular overflow tank (3). An overflow port (9) is arranged on the outer side surface of the annular overflow tank (3). The supernatant inside the solid-liquid separation tank (5) enters the inside of the annular overflow tank (3) through the liquid outlet (31), and then the liquid inside the annular overflow tank (3) is discharged to the outside of the solid-liquid separation device through the overflow port (9).

10. The waste sulfuric acid solid-liquid separation device according to claim 1, characterized in that, A pressure relief port (2) is further provided at the top of the solid-liquid separation tank (5), and the pressure relief port (2) is communicated with the inside of the solid-liquid separation tank (5).

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