Reaction device for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid
By using sludge lime and waste acid solution in waste acid treatment to generate insoluble matter or precipitate in the closed stirred reactor, the complex and cost problems in the existing technology are solved, and efficient and safe waste acid treatment is achieved.
Patent Information
- Application Number
- CN202422509166.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-08-26
- Estimated Expiration
- 2034-10-17
AI Technical Summary
In the prior art, waste acid treatment equipment has a complex structure, a large area, low treatment efficiency and high cost, especially when using liquid alkali treatment, it consumes a large amount of alkali and is prone to produce secondary hazardous waste.
Use slurry lime as an alkaline substance to neutralize and react with waste acid in a closed inverted conical stirred reactor to produce insoluble substances or precipitates. The waste gas and heat during the reaction are treated in combination with the waste gas treatment unit to simplify the process flow and reduce costs.
It has achieved simplification of process flow, reduced production costs, avoided the generation of secondary hazardous waste, and improved processing efficiency and safety.
Smart Images
Figure CN223263825U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a waste acid treatment reaction device, in particular to a reaction device used for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid. Background Art
[0002] With the continuous development of industries such as chemical and metallurgy, the amount of industrial waste acid generated is also increasing. For acids with high concentrations, whose main components are sulfuric acid, phosphoric acid, hydrofluoric acid, or their mixtures, direct resource utilization is difficult or requires pre-treatment at a cost significantly higher than the market value before they can be used. Obviously, harmless disposal is more suitable for the treatment of such acids.
[0003] Existing technologies generally use acid-base neutralization to dispose of waste acid liquid. The commonly used alkali raw materials are mostly liquid alkali (sodium hydroxide), that is, the physical and chemical method of liquid alkali neutralization + flocculation + filter pressing. However, this disposal method consumes a large amount of alkali and the disposal cost is extremely high. It is not suitable for the disposal of such waste acid liquid in large quantities. At the same time, when the waste acid liquid contains a large amount of metal ion components such as copper, zinc, and iron, it is easy to cause secondary hazardous waste. Therefore, the waste acid solution is often treated with low-cost quicklime or slaked lime as an alkaline substance instead of liquid caustic soda. The calcium salt produced by the reaction is used as a poorly soluble substance or precipitate, achieving the purpose of acid-base neutralization and solid slagging. The existing complete set of reaction equipment includes: a lime milk mixing device, a waste acid solution pretreatment device, a crystallization reaction device, a neutralization reaction device, a sedimentation centrifuge device, a solid-liquid separator, etc., and the waste acid solution pretreatment device, crystallization reaction device, and neutralization reaction device must be equipped with a cooling device. The cooling device adopts a multi-stage cooling water circulation mechanism. In order to treat the exhaust gas during the reaction process, multiple gas collection and treatment devices are also installed on the crystallization reaction device and the neutralization reaction device. The main problems of the existing technology are: the large number of equipment and complex structure, resulting in a large floor space, low treatment efficiency, and excessively high operating costs. Utility Model Content
[0004] In order to solve the above deficiencies in the prior art, the present invention aims to provide a reaction device for the disposal of waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid, so as to shorten the process flow and reduce production costs.
[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a reaction device for the disposal of waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid, comprising an alkali liquor premixing unit, a waste acid pretreatment unit, a stirred reactor and a waste gas treatment unit, wherein the alkali liquor premixing unit and the waste acid pretreatment unit are respectively connected to the stirred reactor through pipelines, and the stirred reactor is connected to the waste gas treatment unit.
[0006] As a limitation of the present utility model: the alkali solution premixing unit includes a premixing mixer, a lime milk temporary storage box, and a screw pump connected in sequence, and the screw pump is connected to the stirred reactor; the waste acid pretreatment unit includes a waste acid barrel and a diaphragm pump, and the waste acid barrel is connected to the stirred reactor through a pipeline, and a diaphragm pump is provided between the waste acid barrel and the stirred reactor.
[0007] As a limitation of the present invention: the stirred reactor is in the shape of a closed inverted cone, a discharge port is provided at the bottom, and the upper part is connected to the exhaust gas treatment unit through a pipeline.
[0008] As a limitation of the present invention: a spiral stirring propeller is provided in the stirring reactor, and the spiral stirring propeller is a single-helix or double-helix structure.
[0009] As a limitation of the present invention: the waste gas treatment unit includes alkali solution spraying, activated carbon adsorption, and UV photolysis device.
[0010] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:
[0011] (1) The utility model completes the neutralization and solid slagging reaction in a stirred reactor, replacing the crystallization reaction device, neutralization reaction device, sedimentation centrifuge device, and solid-liquid separator; the waste gas treatment unit is connected to the stirred reactor to guide and treat the large amount of waste gas and high-temperature gas generated during the reaction process, replacing the cooling device required to be equipped on the waste acid liquid pretreatment device, crystallization reaction device, and neutralization reaction device, and the multiple gas collection and treatment devices provided on the crystallization reaction device, neutralization reaction device, etc. Compared with the existing treatment device, the process flow is short, the equipment used in the reaction device is simple in structure, and most of them are conventional equipment in the field, which significantly reduces the operating cost;
[0012] (2) The utility model is a device suitable for using slaked lime (Ca(OH)2) to dispose of waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid. It uses the "slaked lime neutralization and slagging method" and uses slaked lime as an alkali to neutralize sulfuric acid, phosphoric acid and hydrofluoric acid, generating CaSO4, Ca3(PO4)2 and CaF2 insoluble substances or precipitates respectively, which are in a solid state. It achieves the purpose of acid-base neutralization and solid slagging at the same time. It is different from the situation that sodium hydroxide is used to treat waste acid liquid, which is easy to produce secondary hazardous waste. In addition, slaked lime is cheaper than sodium hydroxide, and is suitable for disposing of such waste acid liquid in large quantities, with low production cost.
[0013] (3) The utility model is safe to operate. No one is required to be near the stirred reactor when adding acid or alkali. The sealed inverted conical stirred reactor is connected to an exhaust gas treatment unit to timely discharge and treat the large amount of high-heat and harmful steam generated.
[0014] In summary, the utility model has a short process flow, simple equipment, low cost, and safe operation, and is suitable for the disposal of waste concentrated sulfuric acid, phosphoric acid, and hydrofluoric acid. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.
[0016] Figure 1 It is a structural schematic diagram of an embodiment of the present utility model.
[0017] In the figure: 1- premixer, 2- lime milk temporary storage box, 3- screw pump, 4- waste acid barrel, 5- diaphragm pump, 6- stirred reactor, 7- waste gas treatment unit, 8- material box. DETAILED DESCRIPTION
[0018] The preferred embodiment of the present invention is described below with reference to the accompanying drawings. It should be understood that the reaction device described herein for treating waste concentrated sulfuric acid, phosphoric acid, and hydrofluoric acid is a preferred embodiment and is only used to illustrate and explain the present invention and does not constitute a limitation of the present invention.
[0019] The directional terms or positional relationships such as "up", "down", "left" and "right" described in the present invention are based on the directional relationships in the drawings of the present invention specification and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the content protected by the present invention. Example
[0020] This embodiment Figure 1 The figure shows a reaction device for treating waste concentrated sulfuric acid, phosphoric acid, and hydrofluoric acid, comprising an alkali premixing unit, a waste acid pretreatment unit, a stirred reactor 6, and an exhaust gas treatment unit 7. The alkali premixing unit comprises, from left to right, a premixing mixer 1, a lime milk storage tank 2, and a screw pump 3, which are connected to the stirred reactor 6. The waste acid pretreatment unit comprises a waste acid barrel 4 and a diaphragm pump 5, which are connected to the stirred reactor 6 via a pipeline. A diaphragm pump is provided between the waste acid barrel 4 and the stirred reactor 6. The exhaust gas treatment unit 7 is connected to the stirred reactor 6.
[0021] In premixer 1, slaked lime and water are mixed in a specific proportion to form lime milk, which is then discharged into lime milk storage tank 2 for temporary storage. Screw pump 3 is used to transfer the lime milk from lime milk storage tank 2 to stirred tank reactor 6. In this embodiment, premixer 1 and screw pump 3 can be implemented using conventional technology.
[0022] The waste acid barrel 4 contains waste acid liquid to be treated, and the waste acid barrel 4 is connected to the stirred reactor 6 through a pipeline. A diaphragm pump 5 is provided between the waste acid barrel 4 and the stirred reactor 6. The diaphragm pump 5 can transport the waste acid liquid to the stirred reactor 6. In this embodiment, the diaphragm pump 5 can be an air-operated diaphragm pump of model QBY-50. The air-operated diaphragm pump is remotely operated by a remote control, and personnel are kept away from the waste acid, further ensuring the safety of the operator.
[0023] The acid-base neutralization reaction is more intense, and its reaction process will generate a large amount of heat and smoke. Especially when the waste acid contains some low-boiling organic impurities, these impurities will escape due to the high temperature. The disposal site of the waste acid liquid is prone to produce a large amount of unorganized emission gas, so using an open reactor as a reaction vessel is dangerous. The stirred reactor 6 in the utility model is a closed reactor. Setting it to an inverted cone shape is conducive to the sufficient acid-base neutralization reaction and is conducive to the discharge of reaction waste residue. A spiral stirring paddle with a single or double helix structure is provided in the stirred reactor 6. A variable frequency motor provides power for the stirring paddle, which can increase the rate of the neutralization reaction. A discharge port is provided at the bottom of the stirred reactor 6, and a material box 8 is placed below the discharge port. The upper part of the stirred reactor 6 is connected to the exhaust gas treatment unit 7 through a pipeline, making the stirred reactor 6 a closed and evacuable reactor.
[0024] The exhaust gas treatment unit 7 rapidly extracts the large amounts of heat, smoke, and hazardous gases generated within the stirred reactor 6 for further treatment, ensuring that the treated exhaust meets emission standards. This unit includes, but is not limited to, alkali spraying, activated carbon adsorption, and UV photolysis. This prevents excessive pressure within the reactor, which could lead to accidents such as splashing of waste acid or hazardous gases, causing injuries, or reactor explosions. This ensures production safety, eliminates potential safety hazards for on-site workers, and improves the safety and controllability of the reaction process.
[0025] The design principle and usage method of the utility model are as follows: slaked lime and water are added into a premixer 1 in a certain proportion, the stirring is turned on to mix evenly, lime milk is prepared, and the mixture is discharged into the lime milk temporary storage box 2 for temporary storage; the screw pump 3 is turned on to pump the lime milk into the stirred reactor 6; the pneumatic diaphragm pump 5 is turned on (which can be remotely operated by a remote control, and personnel are away from waste acid to further ensure the safety of the operator), and a determined amount of waste acid is pumped into the reactor, while stirring and reacting for about 20 minutes; after the reaction is completed, the plug-in unloading valve at the bottom of the reactor is opened to discharge the waste residue after the reaction into the material box 8, and the waste residue is finally solid (the water content is required to be less than 60%, which can be controlled by adjusting the proportion of wastewater added when preparing the lime milk) and the pH is neutral; sampling is taken after solidification and curing for 1-2 days, and the test is carried out in accordance with the relevant standards of the "Hazardous Waste Landfill Pollution Control Standard" GB18598-2019. The test indicators meet the flexible landfill entry standards and enter the flexible landfill for safe landfilling. If heavy metals or other indicators are detected that do not meet the direct landfill standards, a certain amount of chelating agents or cement and other curing agents can be added to further solidify the waste before landfilling.
Claims
1. A reaction device for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid, characterized by: The invention comprises an alkali solution premixing unit, a waste acid pretreatment unit, a stirring reactor and a waste gas treatment unit. The alkali solution premixing unit and the waste acid pretreatment unit are respectively connected to the stirring reactor through pipelines, and the stirring reactor is connected to the waste gas treatment unit.
2. A reaction device for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid according to claim 1, characterized in that: The alkali liquor premixing unit includes a premixing mixer, a lime milk temporary storage box, and a screw pump connected in sequence, and the screw pump is connected to the stirred reactor; the waste acid pretreatment unit includes a waste acid barrel and a diaphragm pump, and the waste acid barrel is connected to the stirred reactor through a pipeline, and a diaphragm pump is provided between the waste acid barrel and the stirred reactor.
3. A reaction device for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid according to claim 2, characterized in that: The stirred reactor is in the shape of a closed inverted cone, with a discharge port at the bottom and an upper part connected to the exhaust gas treatment unit through a pipeline.
4. A reaction device for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid according to any one of claims 1 to 3, characterized in that: The stirring reactor is provided with a spiral stirring paddle, which is a single-helix or double-helix structure.
5. A reaction device for treating waste concentrated sulfuric acid, phosphoric acid and hydrofluoric acid according to claim 4, characterized in that: The waste gas treatment unit includes alkali solution spraying, activated carbon adsorption, and UV photolysis devices.