An oil removal device for the rare earth smelting industry

Abstract

This utility model discloses an oil removal device for the rare earth smelting industry, belonging to the field of rare earth smelting oil removal technology. It includes a demulsifier, a bubble generator, and an oil-water separation tank. The inlet of the demulsifier is connected to an oily wastewater conveying pipe, and the outlet of the demulsifier is connected to the inlet of the bubble generator via a pipe and a booster pump. The outlet of the bubble generator is connected to the oil-water separation tank via a pipe. A hydrophilic and oleophobic film plate is installed inside the oil-water separation tank. This utility model has advantages such as high-efficiency removal, continuous operation, low operating cost, strong environmental adaptability, high degree of automation, resource recovery, and reduced wastewater treatment load, making it easy to promote and use.

Description

Technical Field

[0001] This utility model relates to the field of oil removal technology in rare earth smelting, and specifically to an oil removal device for the rare earth smelting industry. Background Technology

[0002] Solvent extraction is currently the mainstream and core technology for the separation and purification of rare earth elements. This process utilizes the difference in partition coefficients between different rare earth ions in the organic phase (extractant + diluent) and the aqueous phase (acid or salt solution) to achieve the production of high-purity single rare earth products through multi-stage countercurrent extraction. In the solvent extraction process, the organic extractant (e.g., P204, Cyanex series) and diluent (e.g., sulfonated kerosene, 260# solvent oil) constitute the main body of the organic phase. Under harsh conditions of long-term operation, high temperature, strong acids and alkalis, and high shear forces, some organic phases may undergo degradation, emulsification, entrainment, and the formation of a third phase. Simultaneously, equipment lubricating greases and hydraulic oils may also be accidentally mixed in. These phenomena lead to the appearance of oil droplets or oil films in aqueous systems such as raffinate (aqueous phase), back-extraction solution, and washing solution, forming organic phase contamination, typically manifesting as floating oil, emulsified oil, or dissolved oil. This is a common problem in the hydrometallurgical process of rare earths.

[0003] The existing degreasing technologies in the rare earth smelting industry and their limitations are as follows:

[0004] 1. Natural sedimentation / gravity separation: This method uses the density difference between oil and water to separate large floating oil particles. However, it has the following disadvantages: extremely low efficiency, excessively long processing time (requiring several hours to several days), basically ineffective for emulsified oil, dissolved oil, and small oil droplets, and occupies a large amount of storage tank space, making it unable to meet the oil removal requirements of continuous production.

[0005] 2. Chemical demulsification / flocculation: Adding demulsifiers or flocculants disrupts the stability of oil droplets, causing them to aggregate, grow larger, and then settle. However, it has the following disadvantages: high cost of chemicals, potential introduction of new impurities that may affect subsequent processes or product quality, generation of sludge containing chemical agents that requires treatment, and high requirements for the selection and dosage control of chemicals.

[0006] 3. Air flotation method: generates microbubbles that adhere to oil droplets and separate them by floating. It has the following disadvantages: the equipment is relatively complex, the operating energy consumption is high (air compressor, dissolved air system), the effect on dissolving oil and fine emulsified oil is limited, and the scum generated needs to be properly treated.

[0007] 4. Adsorption method: This method uses adsorption materials such as activated carbon and resin. However, it has the following disadvantages: limited adsorption capacity, frequent replacement or regeneration is required after adsorption saturation, high operating costs, and it is only suitable for the fine treatment of low-concentration oil pollution.

[0008] 5. Membrane separation method (ultrafiltration / microfiltration): It uses the membrane pore size to trap oil droplets; however, it has the following disadvantages: high investment and operating costs, the membrane is easily contaminated and clogged by oil, the flux decays rapidly, cleaning is frequent and difficult, the membrane life is short, and its application in the complex environment of rare earth smelting with high salt content, strong acid / alkali and high solid content is extremely challenging.

[0009] 6. Centrifugal separation: This method uses centrifugal force to accelerate oil-water separation. However, it has the following disadvantages: expensive equipment, complex maintenance, high energy consumption, limited processing capacity, poor effect on emulsified oil, and unsuitable for large-scale continuous processing.

[0010] In summary, oil pollution generated during solvent extraction processes in rare earth smelting is one of the key bottlenecks restricting production efficiency, product quality, environmental compliance, and economic benefits. Existing oil removal technologies, due to their low efficiency, high cost, complex operation, and poor adaptability, are unable to meet the actual needs of modern, green rare earth smelting enterprises. Therefore, developing a new type of device specifically designed for the rare earth smelting industry, capable of overcoming the aforementioned shortcomings and achieving efficient, economical, stable, and continuous oil removal, has significant practical importance and application value. Utility Model Content

[0011] The purpose of this invention is to provide an oil removal device for the rare earth smelting industry that is efficient, stable, economical, adaptable, easy to maintain, and suitable for continuous production, in view of the prevalence and severity of oil pollution in solvent extraction processes in the rare earth smelting industry and the various limitations of existing oil removal technologies, so as to solve the problems existing in the prior art.

[0012] The technical solution adopted in this utility model is as follows:

[0013] An oil removal device for the rare earth smelting industry includes a demulsifier, a bubble generator, and an oil-water separation tank. The inlet of the demulsifier is connected to an oily wastewater conveying pipe, and the outlet of the demulsifier is connected to the inlet of the bubble generator through a pipe and a booster pump. The outlet of the bubble generator is connected to the oil-water separation tank through a pipe. A hydrophilic and oleophobic film plate is installed inside the oil-water separation tank.

[0014] The oil-water separation tank is divided into a first cavity, a second cavity, and a third cavity from left to right by vertically parallel baffles and a hydrophilic and oleophobic film plate. The baffles are located between the first cavity and the second cavity, and there is a gap between the baffles and the top plate of the oil-water separation tank. The hydrophilic and oleophobic film plate is located between the second cavity and the third cavity.

[0015] An oil phase outlet is provided on the side wall of the oil-water separation tank at the upper part of the second cavity.

[0016] The lower part of the third chamber has an oil-water separation tank with a water phase outlet on its side wall.

[0017] The outlet of the bubble generator's outlet pipe is located in the first chamber of the oil-water separator.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0019] 1. Core Efficiency and Applicability: This invention can efficiently and stably remove floating oil, emulsified oil, and some dissolved oil from the aqueous phase (such as raffinate, back-extraction liquid, washing liquid, etc.) in solvent extraction processes, significantly reducing the oil content of the aqueous phase (<10mg / L), thus solving the problems of low efficiency and inability to adapt to the complex working conditions of existing oil removal technologies. This invention overcomes the shortcomings of existing oil removal technologies in the harsh environments of rare earth smelting, such as strong acids, strong alkalis, high temperatures, high salts, and solid particle content, which are prone to failure. It provides a dedicated oil removal device that is corrosion-resistant, pollution-resistant, and can operate stably for a long time under harsh working conditions.

[0020] 2. Continuous Production and Automation: This invention enables continuous feeding, continuous oil removal, and continuous water discharge, meeting the practical needs of large-scale, continuous rare earth smelting production and solving problems such as excessively long natural settling time and the impact of intermittent operation on the production process. This invention integrates online monitoring (such as oil content and liquid level), automatic sewage / oil discharge, and automatic cleaning (if applicable), reducing manual labor intensity and improving the stability and reliability of the system.

[0021] 3. Operating Costs and Economic Efficiency: This invention reduces the overall operating costs of the oil removal process. Through optimized design, it reduces energy consumption, avoids or minimizes the use of chemical agents (reducing agent costs and the burden of subsequent sludge treatment), and provides an easy-to-maintain structure, reducing maintenance frequency and costs. While efficiently removing oil, this invention also maximizes the recovery and reuse of the separated organic phase (oil phase) (e.g., returning it to the extraction system), reducing the loss of valuable extractants and diluents, and lowering raw material consumption costs.

[0022] 4. Source pollution reduction and environmental benefits: This utility model significantly reduces the load of oil pollutants entering the wastewater treatment system from the source of rare earth smelting process, effectively reducing the difficulty, complexity and cost of subsequent wastewater treatment (such as reducing COD / BOD, reducing the amount of treatment agents, and avoiding impact on the biochemical system), helping enterprises achieve green production and environmental compliance.

[0023] 5. Improve overall process level: This utility model reduces the entrainment loss of rare earth metals in the oil phase through efficient oil removal, and improves the recovery rate of rare earth elements; ensures the purity and quality of products in subsequent processes (precipitation, crystallization, calcination, etc.) (such as avoiding product blackening and performance degradation); maintains the good operating condition of the extraction system (such as preventing pipeline valve blockage and instrument malfunction), thereby improving the efficiency, stability and economic benefits of the rare earth smelting process as a whole.

[0024] In summary, this utility model has the advantages of high efficiency removal, continuous operation, low operating cost, strong environmental adaptability, high degree of automation, recyclable resources, and reduced wastewater treatment load, making it easy to promote and use. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of this utility model;

[0026] In the diagram: 1. Demulsifier; 2. Booster pump; 3. Bubble generator; 4. Oil-water separator; 5. Baffle plate; 6. Hydrophilic and oleophobic film plate; 7. Oil phase outlet; 8. Water phase outlet. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] Example

[0031] like Figure 1 This embodiment provides an oil removal device for the rare earth smelting industry, including a demulsifier 1, a bubble generator 3, and an oil-water separation tank 4. The inlet of the demulsifier 1 is connected to an oily wastewater conveying pipe, and the outlet of the demulsifier 1 is connected to the inlet of the bubble generator 3 via a pipe and a booster pump 2. The outlet of the bubble generator 3 is connected to the oil-water separation tank 4 via a pipe. A hydrophilic and oleophobic membrane plate 6 is installed inside the oil-water separation tank 4. The hydrophilic and oleophobic membrane plate 6 is a nanofiber membrane.

[0032] The oil-water separation tank 4 is divided into a first cavity, a second cavity, and a third cavity from left to right by vertically parallel baffles 5 and hydrophilic and oleophobic film plates 6. The baffles 5 are located between the first cavity and the second cavity, and there is a gap between the baffles 5 and the top plate of the oil-water separation tank 4, that is, the first cavity and the second cavity are connected at the top. The hydrophilic and oleophobic film plates 6 are located between the second cavity and the third cavity.

[0033] An oil phase outlet 7 is provided on the side wall of the oil-water separation tank at the upper part of the second cavity. The oil phase outlet 7 is located below the upper edge of the baffle plate 5.

[0034] The lower part of the third cavity has an oil-water separation tank with a water phase outlet 8 on its side wall.

[0035] The outlet of the outlet pipe of the bubble generator 3 is located in the first cavity of the oil-water separator 4.

[0036] The working principle of this invention is as follows: fine oil droplets disperse in water to form an emulsion. Because the oil droplets in the emulsion are extremely fine, the interfacial film formed on their surface makes it very difficult for the droplets to approach each other. Therefore, to achieve oil-water separation, demulsification must first be performed in a demulsifier. This involves disrupting or weakening the interfacial film encapsulating the dispersed phase droplets, changing the shape of the emulsion or the aggregation shape of the phase droplets, causing the droplets to combine and grow larger, thereby separating the organic phase from the aqueous phase, thus achieving demulsification. The separated liquid enters the oil-water separation tank through a bubble generator. The bubbles encapsulate the outer surface of the organic phase and rise under buoyancy. Further separation occurs through a hydrophilic and oleophobic film plate inside the oil-water separation tank. The aqueous phase is discharged from the bottom of the oil-water separation tank, while the organic phase is collected by overflow from the upper layer, completing the oil-water phase separation.

[0037] like Figure 1 As shown, oily wastewater enters the demulsifier through the inlet and is filtered. The filtered clear liquid exits from the top outlet of the demulsifier and is pressurized by the booster pump into the bubble generator. The bubble generator generates air flotation, and then the liquid flows by gravity from the outlet of the bubble generator into the oil-water separation tank. As the wastewater level in the first chamber rises, it flows by gravity over the baffle plate into the second chamber of the oil-water separation tank. Due to the hydrophilic and oleophobic membrane, the wastewater entering the second chamber passes through the membrane and enters the third chamber of the oil-water separation tank. The aqueous phase flows out from the bottom outlet pipe, and the oil from the second chamber flows out from the oil phase outlet.

[0038] In this invention, wastewater first undergoes demulsification filtration through a demulsification filter. Solid impurities such as calcium sulfate in the wastewater are intercepted on the surface of the filter membrane, thus demulsifying the wastewater. As filtration time increases, oily substances in the wastewater gradually form an oil film on the filter membrane surface, also contributing to demulsification. The filter residue on the membrane surface is ultimately discharged as a slurry, thereby removing solid particles from the wastewater. The demulsification filter membrane is made of high-flow-rate PP material, which is thin and strong, preventing clogging of oily wastewater and facilitating backwashing. This stage of the demulsification filter effectively separates solid particles and performs initial oil-water separation through demulsification.

[0039] The filtered liquid enters a bubble generator and is supplied with compressed air. Utilizing the principle of air flotation for further oil-water separation, the liquid from the bubble generator flows into the first chamber of the oil-water separation tank. As the liquid level rises, it gradually overflows into the second chamber. The hydrophilic-oleophobic membrane is a nanofiber membrane. By altering the properties of the membrane material, water can pass through while oil cannot, causing the oil in the wastewater to gradually accumulate in the second part of the oil-water separation tank and flow out from the oil outlet on the side of the tank. Water passes through the hydrophilic-oleophobic membrane and gradually enters the third part of the oil-water separation tank, flowing out from the water phase oil outlet, thus achieving oil and water separation.

[0040] This invention aims to efficiently remove floating oil, emulsified oil, and dissolved organic contaminants from the aqueous phase of solvent extraction processes, significantly reducing the oil content of the aqueous phase. The device is specially designed to withstand harsh conditions such as strong acids, strong alkalis, high temperatures, high salt content, and solids content, and to achieve continuous and automated operation. It solves the problems of low efficiency, poor adaptability, and inability to meet the needs of continuous production in existing technologies, while simultaneously reducing operating costs and minimizing the loss of valuable organic phases.

[0041] Experimental Example 1

[0042] A cerium chloride solution with an oil content of 72 mg / L after impurity removal was selected. The influent flow rate of the oil removal device was 100 L / min, the wastewater retention time in the oil-water separator was 30 minutes, the effluent flow rate of the aqueous phase was 90 L / min, the oil content in the aqueous phase was measured to be 6 mg / L, and the oil removal rate was 92%, meeting the requirements of subsequent processes. It is evident that the raw water contained impurities and oil and was quite turbid; after treatment by the oil removal device, the water quality was clear and free of impurities.

[0043] Experiment Example 2

[0044] Magnesium sulfate wastewater converted from P507 with an oil content of 182 mg / L was selected. The influent flow rate of the oil removal device was 100 L / min, the wastewater retention time in the oil-water separator was 30 minutes, the effluent flow rate of the aqueous phase was 85 L / min, the oil content of the aqueous phase was detected as 11 mg / L, and the oil removal rate was 94%, meeting the requirements of subsequent processes. It is evident that the raw water contained impurities and oil and was quite turbid. After treatment by the oil removal device, the water quality was clear and free of impurities. Based on the recoverable oil content of 100 mg / L, the magnesium sulfate wastewater treatment capacity was calculated at 300 m³ / h, the annual operating time of the equipment was calculated at 8000 h, and the price of organic phase was calculated at 10,000 yuan / ton, resulting in an annual saving of 2.4 million yuan in organic phase costs.

[0045] Experimental Example 3

[0046] The saponified sodium chloride wastewater with an oil content of 92 mg / L was selected. The influent flow rate of the oil removal device was 100 L / min, the wastewater retention time in the oil-water separator was 30 minutes, the effluent flow rate of the aqueous phase was 90 L / min, the oil content of the aqueous phase was measured to be 10 mg / L, and the oil removal rate was 89%, meeting the requirements of subsequent processes. It is evident that the raw water contained impurities and oil and was quite turbid; after treatment by the oil removal device, the water quality was clear and free of impurities.

Claims

1. An oil removing device for rare earth smelting industry, characterized in that, The device includes a demulsifier, a bubble generator, and an oil-water separation tank. The inlet of the demulsifier is connected to an oily wastewater conveying pipe, and the outlet of the demulsifier is connected to the inlet of the bubble generator via a pipe and a booster pump. The outlet of the bubble generator is connected to the oil-water separation tank via a pipe. A hydrophilic and oleophobic film plate is installed inside the oil-water separation tank.

2. The oil removal device for rare earth smelting industry according to claim 1, characterized in that, The oil-water separation tank is divided into a first cavity, a second cavity, and a third cavity from left to right by vertically parallel baffles and a hydrophilic and oleophobic film plate. The baffles are located between the first cavity and the second cavity, and there is a gap between the baffles and the top plate of the oil-water separation tank. The hydrophilic and oleophobic film plate is located between the second cavity and the third cavity.

3. The oil removal device for rare earth smelting industry according to claim 2, characterized in that, An oil phase outlet is provided on the side wall of the oil-water separation tank at the upper part of the second cavity.

4. The oil removal device for rare earth smelting industry according to claim 3, characterized in that, The lower part of the third chamber has an oil-water separation tank with a water phase outlet on its side wall.

5. The oil removal device for rare earth smelting industry according to claim 4, characterized in that, The outlet of the bubble generator's outlet pipe is located in the first chamber of the oil-water separator.

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