Ionic type rare earth ore leachate purifying and concentrating device
By combining multi-stage sedimentation, sand filtration, and high-packing ceramic membranes with reverse osmosis concentration technology, the problems of easy fouling and short lifespan of hollow fiber membranes in membrane extraction of rare earth minerals have been solved, achieving efficient rare earth concentration and low-cost rare earth recovery.
Patent Information
- Application Number
- CN202423209010.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2034-12-25
AI Technical Summary
Existing membrane extraction methods for rare earth minerals suffer from problems such as easy fouling of hollow fiber membranes, frequent cleaning, short lifespan, and high operating costs, making large-scale industrialization difficult.
The system employs a combination of multi-stage sedimentation, sand filtration, and high-packing ceramic membranes with reverse osmosis concentration technology. First, large suspended solids are removed through a sedimentation tank, then further filtered by a sand filter, followed by purification using a high-packing ceramic membrane, and finally concentration through a reverse osmosis membrane. Regular chemical cleaning is used to maintain the membrane system.
It improves rare earth concentration efficiency, reduces operating costs, extends membrane lifespan, reduces extractant usage, increases rare earth recovery rate and extraction efficiency, and reduces environmental pollution.
Smart Images
Figure CN223837506U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of ion-type rare earth ore extraction technology, and in particular to a purification and concentration device for ion-type rare earth ore leachate. Background Technology
[0002] Due to the unique occurrence of rare earth elements in ion-adsorption rare earth ores, conventional physical beneficiation methods cannot be used to directly extract rare earth elements from the ore. Further extraction requires altering the form of the rare earth elements, which are primarily adsorbed onto the surface of clay minerals in ionic form. Therefore, magnesium sulfate, a leaching agent, can be directly injected into the rare earth mine through wells or tanks, allowing rare earth ions to exchange with the electrolyte solution and enter the solution. However, the rare earth concentration in the magnesium sulfate leaching solution is relatively low, with a low peak value, and a high liquid-to-solid ratio is required for rare earth leaching. Membrane separation methods offer advantages such as high efficiency, stability, and high resource utilization, showing promising prospects in rare earth extraction. However, membrane extraction of rare earths faces technical challenges, including the easy fouling of hollow fiber membranes. The single cleaning cycle of the membrane is short, rarely exceeding 3 days, resulting in low operating efficiency; the membrane's lifetime is also short, rarely exceeding 1 year, requiring frequent replacements and incurring high operating costs. These issues have hindered the large-scale industrial application of membrane extraction for rare earths. Summary of the Invention
[0003] The first objective of this invention is to provide a method for purifying ion-forming rare earth ore leachate. Magnesium sulfate is used as the leaching agent to leach ion-forming rare earths, followed by pretreatment using multi-stage sedimentation and sand filtration, and then purification using a high-packed ceramic membrane. The sedimentation tank removes suspended particles with a density greater than water from the water, sand filtration further removes suspended solids, and the high-packed ceramic membrane reduces the turbidity of the ion-forming rare earth ore leachate to below 0.3 NTU. This solves the problem that hollow fiber ultrafiltration is greatly affected by the sand filtration process during the purification of ion-forming rare earth ore leachate, easily leading to reduced membrane treatment capacity, fiber breakage, frequent cleaning, and short membrane life. The second objective of this invention is to provide a method for concentrating ion-forming rare earth ore leachate. This method uses reverse osmosis to increase the rare earth concentration, further reducing the volume of the ion-forming rare earth leachate, and achieving an ion-forming rare earth rejection rate greater than 99.4%. This reduces the amount of downstream extractant used, improves extraction efficiency, thereby reducing operating costs and mitigating environmental pollution from the extractant. The conductivity of reverse osmosis permeate is less than 100 μS / cm, which can be used as recycled water.
[0004] A purification and concentration device for ion-type rare earth ore leaching solution includes:
[0005] Sedimentation tanks are used for sedimentation and separation of leachate.
[0006] A sand filter, connected to a sedimentation tank, is used to treat the permeate water by sand filtration.
[0007] Ceramic membranes, connected to sand filters, are used to filter the produced water.
[0008] A reverse osmosis membrane, connected to a ceramic membrane, is used for reverse osmosis filtration of product water.
[0009] A chemical cleaning tank, connected to the feed side of the ceramic membrane, is used to pump chemical cleaning solution into the ceramic membrane.
[0010] It also includes heaters installed on chemical cleaning tanks.
[0011] It also includes a permeate tank connected to the permeate side of the reverse osmosis membrane, and a backwash pump connected to the permeate side of the ceramic membrane in the permeate tank for backwashing.
[0012] The ceramic membrane has a pore size of 20-300 nm.
[0013] The quartz sand particles in the sand filter are divided into three layers, with the particle sizes of the quartz sand in each layer from bottom to top being 2-4mm, 1-2mm, and 0.5-1mm, respectively. Beneficial effects
[0014] This invention can purify and concentrate ionic rare earth leachates of various scales and concentrations. Firstly, compared to conventional hollow fiber ultrafiltration technology, the high-packed ceramic membrane offers higher operating flux, longer cleaning cycles, stronger shock resistance, longer replacement cycles, lower requirements for incoming water quality, and lower membrane depreciation costs. Secondly, it provides high reverse osmosis precision, doubling the production capacity after concentration, with a rare earth recovery rate exceeding 99%. The filtration process is phase-change-free and pollution-free, exhibiting strong environmental performance. It improves downstream extraction efficiency, reduces extractant usage, and offers significant economic benefits, making it widely applicable to the purification and concentration of various ionic rare earth leachates. Attached Figure Description
[0015] Figure 1 This is a structural diagram of the apparatus for the method of this utility model.
[0016] 1. Sedimentation tank; 2. Inlet tank; 3. Raw water pump; 4. Sand filter; 5. Self-cleaning filter; 6. High-fill ceramic membrane; 7. Product water tank; 8. Level transmitter; 9. Reverse osmosis feed pump; 10. High-pressure pump; 11. Reverse osmosis membrane; 12. Backwash pump; 13. Chemical cleaning tank; 14. Chemical cleaning pump; 15. Temperature transmitter; 16. Heater. Detailed Implementation
[0017] This utility model relates to a method for extracting rare earth elements from ion-type rare earth ores, comprising the following steps: First, the ion-type rare earth ore leachate is subjected to preliminary precipitation to obtain a raw ion-type rare earth ore leachate solution; second, the raw ion-type rare earth ore leachate solution is filtered through a sand filter to remove large molecular solid particles and suspended matter, and the permeate from the sand filter is further filtered through a high-packed ceramic membrane to remove colloids, proteins, microorganisms, and large molecular organic matter; finally, the permeate from the high-packed ceramic membrane is concentrated by reverse osmosis to obtain a reverse osmosis concentrate and permeate. The high-packed ceramic membrane maintains a recovery rate of over 90%, controls the flux at over 80 LMH, and periodically backwashes to restore the permeate flux. Reverse osmosis is concentrated at a recovery rate of over 50%, and the concentrate is used as the mother liquor for ion-type rare earth extraction, while the permeate is reused. The low rare earth concentration, high impurity content, and large volume of the ion-type rare earth ore leachate lead to high consumption of extraction reagents, high transportation costs, and low rare earth recovery rates, resulting in resource waste. This method can increase the concentration of ion-adsorption rare earth ore leachate, improve rare earth extraction efficiency, reduce the amount of extractant used, lower operating costs, and increase rare earth extraction capacity by more than two times. It is conducive to the industrial promotion of membrane treatment of ion-adsorption rare earth ore leachate.
[0018] In some embodiments, the method for extracting rare earth elements from ion-adsorption rare earth ores provided by this invention includes:
[0019] S1. The ion-type rare earth leachate undergoes preliminary pretreatment, followed by sedimentation in a sedimentation tank to remove large suspended particles. This process utilizes the density difference between suspended particles and water, causing them to settle under gravity, thus achieving solid-liquid separation.
[0020] S2. The effluent from the sedimentation tank is further filtered by a sand filter. Through the dual action of physical filtration and deep filtration, the sand filter can effectively remove suspended solids and particulate matter from the water. The turbidity of the sand-filtered water is below 6 NTU.
[0021] S3. The ion-type rare earth leachate that has passed through the sand filter is purified by a high-packing ceramic membrane. The operating temperature of the high-packing ceramic membrane is between 18-25℃, the equipment pressure is adjusted to 1-2 bar, the rare earth leachate recovery rate is kept above 90%, and the turbidity of the rare earth leachate effluent from the high-packing ceramic membrane is less than 0.3 NTU.
[0022] S4. High-filling ceramic membranes can be backwashed regularly to reduce the accumulation of pollutants, and can also be chemically cleaned to completely restore the permeate flux of high-filling ceramic membranes.
[0023] S5. The permeate produced by the high-filling ceramic membrane is filtered and concentrated by reverse osmosis membrane technology. The surface micropore diameter of the reverse osmosis membrane is 0.5-10nm. The reverse osmosis process temperature is controlled at 18-25℃ and the equipment pressure is adjusted to 10-15bar. The retentate is rare earth leachate concentrate and the filtrate is permeate, with a concentration of more than 2.5 times.
[0024] S6. Forward rinsing of reverse osmosis membranes at regular intervals can reduce concentration polarization on the membrane surface.
[0025] S7. The reverse osmosis membrane concentrate enters the extraction section to extract rare earth elements from the concentrate. The permeate from the reverse osmosis is then used as recycled water.
[0026] Furthermore, the sedimentation time in the sedimentation tank in step S1 is 2-3 hours.
[0027] Furthermore, the quartz sand particle sizes in the sand filter in S2 are 2-4 mm, 1-2 mm, and 0.5-1 mm from bottom to top, respectively.
[0028] Furthermore, the high-filling ceramic membrane accuracy in step S3 is 50 nm.
[0029] Furthermore, in step S3, the high-packed ceramic membrane is backwashed every 40-60 minutes, and the backwash liquid is the permeate from the high-packed ceramic membrane.
[0030] Furthermore, in step S3, the highly packed ceramic membrane is chemically cleaned every 7-10 days.
[0031] Furthermore, the reverse osmosis membrane in step S4 is a fouling-resistant, low-energy brackish water reverse osmosis membrane.
[0032] Furthermore, the reverse osmosis membrane in step S4 operates in a two-stage configuration, arranged in a 2:1 ratio.
[0033] Furthermore, the reverse osmosis membrane in step S4 has a rejection rate of over 99.4% for ion-adsorption rare earth elements.
[0034] Furthermore, in step S6, the reverse osmosis membrane is run for 3-4 hours and then flushed for 30-60 seconds.
[0035] like Figure 1As shown, the apparatus used in the method for extracting rare earth from ion-adsorption rare earth ore according to this utility model includes a sedimentation tank 1, a water inlet tank 2, a raw water pump 3, a sand filter 4, a self-cleaning filter 5, a high-fill ceramic membrane 6, a product water tank 7, a level transmitter 8, a reverse osmosis feed pump 9, a high-pressure pump 10, a reverse osmosis membrane 11, a backwash pump 12, a chemical cleaning tank 13, a chemical cleaning pump 14, a temperature transmitter 15, and a heater 16; wherein, the ion-adsorption rare earth leachate in the sedimentation tank 1 is fed into the sand filter via the raw water pump 2. In filter 3, after filtration by sand filter 3, sand filter permeate is obtained. Sand filter permeate is connected to high-packed ceramic membrane 6 through self-cleaning filter 5. Self-cleaning filter 5 prevents quartz sand from entering high-packed ceramic membrane 6. Permeate enters high-packed ceramic membrane 6 for filtration. High-packed ceramic membrane permeate is transported to permeate tank 7. Permeate tank 7 is equipped with level transmitter 8 to monitor the level of permeate tank 7. Level transmitter 8 is interlocked with reverse osmosis feed pump 9 to control the start and stop of reverse osmosis feed pump 9 and high-pressure pump 10. The filtrate in the product water tank 7 is transported to the reverse osmosis membrane 11 for filtration via the reverse osmosis feed pump 9 and the high-pressure pump 10. The concentrate from the reverse osmosis membrane 11 is used for downstream extraction, and the product water is reused. The filtrate in the product water tank 7 is backwashed periodically by the backwash pump 12 to the high-packed ceramic membrane 6. The backwash water is returned to the upstream sedimentation tank 1. The packed ceramic membrane 6 can be chemically cleaned periodically to restore the product water flux. The chemical reagents are prepared in the chemical cleaning tank 13. The chemical cleaning tank 13 is equipped with a heater 16, which heats the cleaning solution. The chemical cleaning tank 13 is equipped with a temperature transmitter 15, which is used to monitor the cleaning temperature in the chemical cleaning tank 13. Example 1
[0036] The purification and concentration method for ion-type rare earth ore leaching solution provided in this embodiment specifically includes the following steps:
[0037] The leaching solution of ion-adsorption rare earth minerals has a conductivity of 4000 μs / cm and a rare earth content of 200 ppm.
[0038] The ion-adsorption rare earth ore leaching solution undergoes preliminary sedimentation in a sedimentation tank. The hydraulic retention time in the sedimentation tank is 2 hours, and the turbidity of the supernatant of the ion-adsorption rare earth ore leaching solution after sedimentation is 30 NTU.
[0039] The effluent from the sedimentation tank is filtered through a sand filter by a water supply pump. The sand filter tank is filled to a height of 1m, which can further remove the remaining suspended solids and particulate matter. The sand filter pressure is 1 bar, the temperature is controlled at 18℃, the sand filter speed is 10m / h, and the turbidity of the sand filter effluent is 6 NTU.
[0040] The effluent from the sand filter enters the high-packed ceramic membrane filtration system, which removes suspended solids, colloids, bacteria, macromolecular organic matter, and other harmful substances from the water. The high-packed ceramic membrane filtration pressure is 1 bar, the temperature is controlled at 18℃, and the recovery rate is controlled at 90%. The turbidity of the high-packed ceramic membrane permeate is less than 0.3 NTU. The high-packed ceramic membrane is backwashed for 20 seconds every 45 minutes of filtration. Each backwash can increase the membrane flux by 8%. The concentrate from the high-packed ceramic membrane returns to the front-end sedimentation tank, while the permeate enters the permeate tank.
[0041] High-packed ceramic membranes require chemical cleaning every 10 days. The chemical cleaning temperature is controlled at 35-40℃, the cleaning pressure is 1 bar, the cleaning time is 5 hours, and the cleaning agent is 1% sodium hydroxide + 0.5% sodium hypochlorite. After each chemical cleaning, the flux of the high-packed ceramic membrane can be restored to more than 90% of the original flux.
[0042] Permeate from the high-packed ceramic membrane enters the reverse osmosis filtration system via a reverse osmosis feed pump and a high-pressure pump. During reverse osmosis operation, the temperature is controlled at 18℃, the equipment pressure is regulated at 10 bar, the permeate flux is 17 LMH, and the concentration factor is 2.5 times. The retained substance is ionic rare earth concentrate, with a rare earth concentration of 498.5 ppm after concentration, achieving a rare earth rejection rate of 99.5%. The filtrate is permeate with a conductivity of 32 μS / cm. A 40-second forward flush is performed every 3 hours of reverse osmosis filtration. Regular flushing of the reverse osmosis membrane effectively reduces concentration polarization and prevents scaling. The concentrate from the reverse osmosis membrane enters the extraction section. The concentrated rare earth solution improves extraction efficiency, reduces extractant usage, lowers operating costs, and reduces environmental pollution. The filtrate from reverse osmosis is permeate and is reused as recycled water. Example 2
[0043] The purification and concentration method for ion-type rare earth ore leaching solution provided in this embodiment specifically includes the following steps:
[0044] The leaching solution of ion-adsorption rare earth minerals has a conductivity of 6800 μs / cm and a rare earth content of 450 ppm.
[0045] The ion-adsorption rare earth ore leaching solution undergoes preliminary sedimentation in a sedimentation tank with a hydraulic retention time of 3 hours. The turbidity of the supernatant of the ion-adsorption rare earth ore leaching solution after sedimentation is 25 NTU.
[0046] The effluent from the sedimentation tank is filtered through a sand filter by a water supply pump. The sand filter has a filling height of 1m, which can further remove the remaining suspended solids and particulate matter. The sand filter pressure is 2 bar, the temperature is controlled at 22℃, the sand filter filtration speed is 8m / h, and the turbidity of the sand-filtered effluent is 4 NTU.
[0047] The effluent from the sand filter enters the high-packed ceramic membrane filtration system, which removes suspended solids, colloids, bacteria, macromolecular organic matter, and other harmful substances from the water. The high-packed ceramic membrane filtration pressure is 2 bar, the temperature is controlled at 22℃, and the recovery rate is controlled at 95%. The turbidity of the high-packed ceramic membrane permeate is less than 0.2 NTU. The high-packed ceramic membrane is backwashed for 30 seconds every 60 minutes of filtration. Each backwash can increase the membrane flux by 15%. The concentrate from the high-packed ceramic membrane returns to the front-end sedimentation tank, while the permeate enters the permeate tank.
[0048] High-packed ceramic membranes require chemical cleaning every 7 days. The chemical cleaning temperature is controlled at 35-40℃, the cleaning pressure is 1 bar, the cleaning time is 5 hours, and the cleaning agent is 1% sodium hydroxide + 1% sodium hypochlorite. After each chemical cleaning, the flux of the high-packed ceramic membrane can be restored to 97% of the original flux.
[0049] Permeate from the high-packed ceramic membrane enters the reverse osmosis filtration system via a reverse osmosis feed pump and a high-pressure pump. During reverse osmosis operation, the temperature is controlled at 22℃, the equipment pressure is adjusted to 12 bar, the permeate flux is 22 LMH, and the concentration factor is 2.85. The retained substance is ionic rare earth concentrate, and the concentration of rare earth elements in the reverse osmosis concentrate after concentration is 1283 ppm, achieving a rare earth rejection rate of 99.7%. The filtrate is permeate with a conductivity of 20.4 μS / cm.
[0050] After 4 hours of reverse osmosis filtration, a 60-second forward flush is performed. By flushing the reverse osmosis membrane regularly, the concentration polarization phenomenon of the reverse osmosis membrane can be effectively reduced, and scaling on the membrane surface can be prevented.
[0051] The concentrate from the reverse osmosis membrane enters the extraction section. The concentrated rare earth solution improves extraction efficiency, reduces the amount of extractant used, lowers operating costs, and reduces environmental pollution. The filtrate from reverse osmosis is the product water, which is reused as recycled water.
Claims
1. A purification and concentration device for ion-type rare earth ore leaching solution, characterized in that, include: Sedimentation tank (1) is used for sedimentation and separation of leachate; A sand filter (3) is connected to a sedimentation tank (1) and is used for sand filtration of the permeate. A ceramic membrane (5) is connected to a sand filter (3) for filtering the produced water. A reverse osmosis membrane (11) is connected to a ceramic membrane (5) and is used for reverse osmosis filtration of the product water. A chemical cleaning tank (13) is connected to the feed side of the ceramic membrane (5) and is used to pump chemical cleaning solution into the ceramic membrane (5).
2. The purification and concentration device for ion-type rare earth ore leaching solution according to claim 1, characterized in that, It also includes a heater (16) installed on the chemical cleaning tank (13).
3. The purification and concentration device for ion-type rare earth ore leaching solution according to claim 1, characterized in that, It also includes a product water tank (7) connected to the permeate side of the reverse osmosis membrane (11), and a backwash pump (12) for backwashing the product water tank (7) connected to the permeate side of the ceramic membrane (5).
4. The purification and concentration device for ion-type rare earth ore leaching solution according to claim 1, characterized in that, The ceramic membrane has a pore size of 20-300 nm.
5. The purification and concentration device for ion-type rare earth ore leaching solution according to claim 1, characterized in that, The quartz sand particles in the sand filter are divided into three layers, with the particle sizes of the quartz sand in each layer from bottom to top being 2-4mm, 1-2mm, and 0.5-1mm, respectively.