Galvanizing pickling waste liquid treatment device

Abstract

The galvanizing pickling waste liquid treatment device comprises a first storage tank, a reaction tank and a filter pressing device which are connected in sequence, the first storage tank is used for storing the galvanizing pickling waste liquid; the reaction tank is also connected with a first adjusting tank for storing lime slurry and a second adjusting tank for storing hydrogen peroxide; a liquid outlet of the filter pressing device is connected with a second storage tank, and the second storage tank is used for storing zinc-rich filtrate; a slag outlet of the filter pressing device is connected with a storage hopper; and the storage hopper is used for storing an iron-containing filter cake. According to the galvanizing pickling waste liquid treatment device, zinc and iron in the galvanizing pickling waste liquid can be recycled while low-cost and harmless treatment of the galvanizing pickling waste liquid is achieved, large-scale processing production is achieved, and the galvanizing pickling waste liquid treatment device has good application and popularization value.

Description

Technical Field

[0001] The utility model relates to the field of hazardous waste treatment, in particular to a galvanizing pickling waste liquid treatment device. Background Art

[0002] Pickling and rust removal primarily involves immersion in hydrochloric acid. Galvanized components (including re-plated components) are immersed in a certain concentration of hydrochloric acid for 5–10 minutes. Iron oxides on the component surface dissolve in the hydrochloric acid, and the elemental iron reacts with the acid to produce hydrogen, further promoting the flaking of the oxide layer. As the hydrochloric acid is consumed, when the hydrogen ion concentration no longer meets production requirements, it must be replaced and discharged, becoming HW34 waste acid hazardous waste (900-300-34). This waste acid is dark green in color and has a small amount of oil on the surface. In addition to residual hydrochloric acid, it contains significant amounts of iron and zinc, as well as small amounts of heavy metal ions such as lead, nickel, and chromium. Typical concentrations of iron, for example, range from 100,000 to 220,000 mg / L, and zinc, from 80,000 to 150,000 mg / L.

[0003] In the prior art, the common disposal method for zinc pickling waste liquid is the neutralization precipitation method, which uses slaked lime to neutralize the waste acid and precipitate the metal ions therein. This method is simple to operate, but the amount of lime used is large, the secondary pollutant waste residue output is large, the disposal efficiency is low, and a large amount of zinc and iron metals are not recycled, resulting in a waste of resources. In order to further recycle zinc and iron resources, researchers have carried out a large amount of research. For example, Chinese patent publication number CN109574349A discloses a method for recovering ferric chloride from zinc plating waste acid using concentrated crystallization. After pretreatment, the waste acid is oxidized using hydrogen peroxide to convert the ferrous iron in the solution into ferric iron, and then vacuum distillation is performed to recover dilute acid and ferric chloride crystals. However, this method is not suitable for waste acid solutions with a high zinc content, and acid distillation has high requirements for equipment corrosion protection, making it unsuitable for small-scale production. Chinese patent publication number CN110841331A discloses a method for separating iron and zinc from zinc plating waste acid using resin selective adsorption. After removing suspended matter and impurities, the waste acid is passed through a two-stage series of resin columns, which selectively adsorb zinc ions, achieving an effluent zinc ion concentration of less than 5 mg / L, thus achieving iron-zinc separation. Zinc is eluted and concentrated to recover zinc chloride, and the iron-containing effluent is oxidized to produce ferric chloride. This method is simple and eliminates secondary pollutants, but resin activation and elution consume significant water, leading to high resin costs. Alternatively, extraction methods offer excellent separation results and allow for continuous production. However, the extraction reagents are expensive, making them typically used for the separation and purification of high-value (rare) metals, making them less costly.

[0004] Therefore, the utility model aims to develop a galvanizing pickling waste liquid treatment device to achieve low-cost and harmless disposal of galvanizing pickling waste liquid, while recovering zinc and iron in the galvanizing pickling waste liquid and realizing large-scale processing and production. Summary of the Invention

[0005] The technical problem solved by the utility model is to provide a galvanizing pickling waste liquid treatment device to solve the shortcomings of the above-mentioned background technology.

[0006] The technical problem solved by the present invention is achieved by the following technical solutions:

[0007] A galvanizing pickling waste liquid treatment device comprises a first storage tank, a reaction tank, and a filter press device connected in sequence; the first storage tank is used to store the galvanizing pickling waste liquid; the reaction tank is further connected to a first regulating tank for storing lime slurry and a second regulating tank for storing hydrogen peroxide; the liquid outlet of the filter press device is connected to the second storage tank, which is used to store zinc-rich filtrate; the slag outlet of the filter press device is connected to a storage hopper, which is used to store iron-containing filter cake.

[0008] In the utility model, a seed chamber is provided between the reaction tank and the filter press device.

[0009] In the utility model, the pipeline connecting the seed chamber and the filter press device is connected to the compressed air branch pipe.

[0010] In the present invention, the reaction tank is a jacketed reaction tank, a discharge port is provided at the bottom of the reaction tank, the discharge port is connected to the heat exchange device through the first discharge pipe, the heat exchange device is provided in the first storage tank, and the outlet of the heat exchange device is connected to the filtering device.

[0011] In the present invention, the heat exchange device is a heat exchange coil.

[0012] In the utility model, the discharge pipe of the reaction tank is connected to the filter press device through the second discharge pipe.

[0013] In the present invention, the feed port of the first storage tank is connected to the first filtering device, and the first filtering device is a Y-type filter with 18 to 30 meshes.

[0014] In the present invention, the discharge port of the first storage tank is arranged at the bottom or lower part, and a second filtering device is arranged between the first storage tank and the reaction tank. The second filtering device is a 100-200 mesh basket filter.

[0015] In the utility model, a transparent observation window is provided in the first storage tank.

[0016] Beneficial effects: The galvanizing pickling waste liquid treatment device described in the utility model can realize intermittent feeding and continuous processing of galvanizing pickling, realize the harmless disposal of galvanizing waste acid liquid, and realize the separate recovery of iron and zinc elements. Compared with methods such as resin treatment and extraction, it significantly reduces reagent costs and production costs.

[0017] The galvanizing pickling waste liquid treatment device described in the utility model has an easy-to-control production process, high production efficiency, and strong equipment compatibility. It only requires small-scale modifications to conventional equipment to meet production needs, and is suitable for large-scale promotion and application.

[0018] The galvanizing pickling waste liquid treatment device described in the utility model fully utilizes thermal energy and has a high energy efficiency ratio. Through the heat exchange between the first storage tank and the reaction tank, the waste heat of the material is utilized, and the seed addition is achieved through the setting of the seed chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention.

[0020] Among them: 1. First storage tank; 2. Reaction tank; 3. Filter press; 4. Second storage tank; 5. Storage hopper; 6. First filter device; 7. Second filter device; 8. First regulating tank; 10. Second regulating tank; 11. First discharge pipe; 12. Second discharge pipe; 13. Seed chamber; 14. Heat exchange device; 15. Compressed air branch pipe. DETAILED DESCRIPTION

[0021] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations.

[0022] See also Figure 1 A galvanizing pickling waste liquid treatment device comprises a first storage tank 1, a reaction tank 2, and a filter press device 3 connected in sequence.

[0023] The first storage tank 1 is used to store galvanized pickling waste liquid. The feed port of the first storage tank 1 is connected to a first filter device 6. In a preferred embodiment, the first filter device 6 is a Y-type filter with an 18-30 mesh size. The first filter device 6 prevents larger impurities in the galvanized pickling waste liquid from entering the first storage tank 1, thereby reducing the formation of bottom sludge in the first storage tank 1. In a preferred embodiment, the first storage tank 1 is a transparent storage tank or is equipped with a transparent observation window. The galvanized pickling waste liquid is allowed to stand and stratify in the first storage tank 1, achieving separation of the oil layer and the water layer.

[0024] The discharge port of the first storage tank 1 is located at the bottom or lower portion, allowing the water layer in the first storage tank 1 to enter the reaction tank 2. A second filter device 7, a 100-200 mesh basket filter, is installed between the first storage tank 1 and the reaction tank 2. This filter device 7 allows the zinc plating pickling wastewater, which has undergone oil-water separation, to undergo a second filtration process before entering the reaction tank 2.

[0025] In a preferred embodiment, the reaction tank 2 is a jacketed reaction tank 2, a stirring mechanism is provided in the reaction tank 2, and the reaction tank 2 is further connected to a first regulating tank 8 for storing lime slurry and a second regulating tank 10 for storing hydrogen peroxide. In actual operation, a heating interlayer is provided on the outside of the jacketed reaction tank 2, and the heating interlayer is connected to an external steam heating device, so that the reaction temperature in the jacketed reaction tank 2 is maintained at 80-95°C. First, the lime slurry in the first regulating tank 8 is added to the reaction tank 2 to adjust the pH of the feed liquid, and then the hydrogen peroxide in the second regulating tank 10 is added to the reaction tank 2, and the addition rate of the hydrogen peroxide is controlled by a flow meter; preferably, the second regulating tank 10 is connected to a spray head provided on the top of the reaction tank 2, so that the hydrogen peroxide is added in a spraying manner; during the reaction process, the lime slurry in the first regulating tank 8 is added simultaneously to maintain the pH stability of the system.

[0026] As an improvement to this embodiment, a pH sensor and an oxidation-reduction potential sensor are provided in the reaction tank.

[0027] The reaction tank 2 is connected to the filter press 3, the liquid outlet of the filter press 3 is connected to the second storage tank 4, the second storage tank 4 is used to store the zinc-rich filtrate, and the zinc-rich filtrate is precipitated with liquid alkali to obtain a zinc hydroxide product; the slag outlet of the filter press 3 is connected to the storage hopper 5, and the storage hopper 5 is used to store the iron-containing filter cake. The iron-containing filter cake is mainly composed of ferric oxyhydroxide and contains only a small amount of ferric hydroxide, which can be used as an iron-making raw material or roasted to prepare iron red. Therefore, the system described in the present invention can achieve efficient separation of zinc and iron elements, more than 99.5% of the iron element enters the iron-containing filter cake, achieving sufficient separation of iron and zinc, and less Zn is entrained and adsorbed in the iron-containing filter cake, and the Zn recovery rate is as high as more than 95%.

[0028] As an improvement to the present invention, a seed chamber 13 is provided between the reaction tank 2 and the filter press 3, and the pipeline connecting the seed chamber 13 and the filter press 3 is connected to a compressed air branch pipe 15. Thus, compressed air can be used to add slurry remaining in the pipeline from the previous batch of material as seed crystals to the jacketed reaction tank 2, with the seed crystal addition ratio being 5% to 15%. The compressed air branch pipe 15 can also serve as an aeration mechanism according to actual needs.

[0029] As a further improvement to the present invention, the discharge port at the bottom of the reactor 2 is connected to a heat exchanger 14 via a first discharge pipe 11. Heat exchanger 14 is disposed within the first storage tank 1. The outlet of heat exchanger 14 is connected to the seed chamber 13, which is in turn connected to the filtration device. Heat exchanger 14 is preferably a heat exchange coil, thereby enabling heat recycling within the reactor 2. The discharge port of the reactor 2 is connected to the filter press 3 via a second discharge pipe 12. This allows for the selection of a heat exchange or non-heat exchange process based on actual production needs.

[0030] Compared with the traditional simple neutralization and precipitation system, the disposal device described in the utility model has a higher utilization rate of lime, can save 10% to 20% of lime, and does not produce secondary pollutants, does not need to be landfilled, and the product has value, and the overall benefit is better.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two components.

[0034] The above content is a further detailed description of the present invention in combination with specific implementation methods, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention.

Claims

1. A galvanizing pickling waste liquid treatment device, characterized in that: It includes a first storage tank, a reaction tank, and a filter press device that are connected in sequence; the first storage tank is used to store galvanized pickling waste liquid; the reaction tank is also connected to a first regulating tank for storing lime slurry and a second regulating tank for storing hydrogen peroxide; the liquid outlet of the filter press device is connected to the second storage tank, which is used to store zinc-rich filtrate; the slag outlet of the filter press device is connected to a storage hopper, which is used to store iron-containing filter cake.

2. The galvanizing pickling waste liquid treatment device according to claim 1, characterized in that: A seed chamber is provided between the reaction tank and the filter press device.

3. The galvanizing pickling waste liquid treatment device according to claim 2, characterized in that: The pipeline connecting the seed chamber and the filter press device is connected to the compressed air branch pipe.

4. The galvanizing pickling waste liquid treatment device according to claim 1, characterized in that: The reaction tank is a jacketed reaction tank, a discharge port is provided at the bottom of the reaction tank, the discharge port is connected to a heat exchange device through a first discharge pipe, the heat exchange device is provided in the first storage tank, and the outlet of the heat exchange device is connected to the filter press device.

5. The galvanizing pickling waste liquid treatment device according to claim 4, characterized in that: The heat exchange device is a heat exchange coil.

6. The galvanizing pickling waste liquid treatment device according to claim 4, characterized in that: The discharge pipe of the reaction tank is connected to the filter press device through a second discharge pipe.

7. The galvanizing pickling waste liquid treatment device according to claim 1, characterized in that: The feed port of the first storage tank is connected to a first filtering device, which is a Y-type filter with an 18-30 mesh.

8. The galvanizing pickling waste liquid treatment device according to claim 1, characterized in that: The discharge port of the first storage tank is arranged at the bottom or lower part, and a second filtering device is arranged between the first storage tank and the reaction tank. The second filtering device is a 100-200 mesh basket filter.

9. The galvanizing pickling waste liquid treatment device according to claim 1, characterized in that: A transparent observation window is provided in the first storage tank.

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