System and method for separating fine particles from slurry

Abstract

A system (10) has first and second particle separators (100, 200) including first and second vessels (110, 210). A first inlet (115) receives a slurry and carrier particles in the first vessel (110). A first fluidizing device (120) generates a fluidized bed (140) in the first vessel (110) and a coalescing zone (150) is formed therein such that fine particles adhere to the carrier particles, forming agglomerates and separating from the gangue particles. A first outlet (160) removes a first underflow including the agglomerates from the first vessel (110). The second particle separator (200) has a second inlet (215) for receiving the first underflow. A second fluidizing device (220) generates a second fluidized bed (240) separating the first underflow into a second underflow including the carrier particles and an overflow including the fine particles. A second outlet (260) removes the second underflow and a launder (285) receives the overflow.

Description

Technical Field

[0001] This invention relates to a system and method for separating fine particles from slurries, and more particularly to a system and method for separating fine mineral particles from mineral or ore slurries. The invention has been primarily developed for separating rare earth minerals from ore slurries, and this application will be described below with reference to it. However, it should be understood that the invention is not limited to this application and can also be used for separating fine particles, including bubbles and droplets, from slurries and other suspensions. Background Technology

[0002] The following discussion of the prior art is intended to provide a suitable technical background for the present invention and to allow for a full understanding of its advantages. However, unless otherwise expressly stated, any reference to the prior art in this specification should not be construed as an express or implied admission that the art is widely known or constitutes common general knowledge in the field.

[0003] In the mining and mineral industry, rare earth minerals (REMs) are typically found in clay derived from weathered ore bodies. These REM particles can range in size from less than 1 micrometer to several micrometers, or even tens of micrometers. Despite their relatively low concentration in ores, REMs remain valuable minerals due to their widespread use in many modern technologies such as smartphones, LEDs, and other electronic devices.

[0004] REM is typically refined using a variety of separation processes, such as gravity separation, flotation, or even magnetic separation. During these processes, chemical reagents are added to aid in the aggregation of REM particles. The resulting REM concentrate is then leached with a suitable acid, filtered or decanted, and then extracted using a solvent to separate individual REM particles.

[0005] The main problem with these existing methods for extracting REM from clay-like materials is the excessive consumption of chemicals, as large quantities of chemical reagents are typically required during the separation process, especially for dissolving REM. This leads to serious environmental impacts; for example, land pollution due to the use of leaching ponds containing chemicals. Consequently, the costs of managing and mitigating these environmental impacts are quite high.

[0006] Furthermore, the resulting purification effect (the quality of recovered REM) is often poor, thus reducing the economic efficiency of REM extraction. Novel reagents with high selectivity favorable to specific REMs can be used to improve the efficiency of the separation process. However, the preparation of such reagents can be very expensive. A good example of such reagents is a peptide composed of an amino acid sequence. Therefore, current refining methods that lead to excessive consumption of such novel reagents are considered uneconomical, particularly in the mining industry.

[0007] The object of this invention is to overcome or substantially improve one or more disadvantages in the prior art, or at least to provide a useful alternative. In at least one preferred form, the object of this invention is to provide an improved system and method for extracting REM, or at least to improve process efficiency, save on chemical usage, and minimize harmful environmental impact. Summary of the Invention

[0008] A first aspect of the present invention provides a system for separating fine particles from gangue particles in a slurry, comprising: A first particle separator, the first particle separator comprising: A first container having a first inlet for receiving slurry and carrier particles; A first fluidizing device, located at one end of a container, is used to generate a first fluidized flow of fluidizing fluid and to create a first fluidized bed in the first container, wherein an agglomeration zone is formed within the first fluidized bed, causing fine particles to adhere to carrier particles to form aggregates; and A first outlet is provided for removing a first underflow from the container, wherein the first underflow comprises coalesces; The first particle separator is configured to separate aggregates from gangue particles; and A second particle separator, configured to separate aggregates into fine particles and carrier particles, includes: The second container has a second inlet for receiving the first underflow from the first particle separator; A second fluidizing device, located at one end of a second container, is used to generate a second fluidizing flow of fluidizing fluid to break up agglomerates and create a second fluidized bed in the second container; A second outlet is provided for removing a second underflow from a second container, wherein the second underflow comprises carrier particles; and The second flow channel is used to receive the overflow, which includes fine particles.

[0009] In one or more embodiments, the second particle separator includes multiple inclined channels for separating fine particles from carrier particles.

[0010] In one or more embodiments, the first particle separator includes a plurality of inclined channels for separating aggregates from gangue particles, the inclined channels being located above the agglomeration zone.

[0011] In one or more embodiments, the fluidizing fluid in the second particle separator promotes the separation of fine particles from the carrier particles. That is, the fluidizing fluid breaks up the aggregates. In one or more embodiments, the pH of the fluidizing fluid in the second particle separator is different from the pH of the fluidizing fluid in the first particle separator to promote the separation of fine particles from the carrier particles. In one or more embodiments, the pH of the fluidizing fluid in the second particle separator is lower than the pH of the fluidizing fluid in the first particle separator to promote the separation of fine particles from the carrier particles. Alternatively, in one or more embodiments, the temperature of the fluidizing fluid in the second particle separator is different from the temperature of the fluidizing fluid in the first particle separator to promote the separation of fine particles from the carrier particles. Those skilled in the art will understand that different methods can be used to promote the separation of fine particles from the carrier particles based on chemical functionality.

[0012] In one or more embodiments, a feed conduit is connected to a first inlet for conveying the slurry and carrier particles into a first particle separator. In one or more embodiments, the feed conduit includes an online mixer for premixing the slurry and carrier particles before they are fed into the first particle separator.

[0013] In one or more embodiments, the system includes a recirculation conduit for recirculating a second underflow to a first particle separator. In one or more embodiments, the recirculation conduit is fluidly connected to a feed conduit.

[0014] In one or more embodiments, the first particle separator includes a first flow channel for receiving gangue particles, the first flow channel being fluidly connected to a dewatering device for separating the gangue particles from the fluidizing fluid. In one or more embodiments, the fluidizing fluid is recycled to a feed line.

[0015] In one or more embodiments, the second flow channel is fluidly connected to a dewatering device for separating fine particles from the fluidizing fluid. In one or more embodiments, the fluidizing fluid is recycled to the second fluidizing device.

[0016] In one or more embodiments, each of the carrier particles includes a coarse-sized particle bound to one or more adsorbent particles. In one or more embodiments, the one or more adsorbent particles include a peptide. In one or more embodiments, the peptide exhibits high selectivity for fine particles. In one or more embodiments, the peptide exhibits high selectivity for multiple types of fine particles. In one or more embodiments, the one or more adsorbent particles include more than one type of peptide.

[0017] In one or more embodiments, each of the support particles comprises an ion exchange resin particle. In one or more embodiments, each of the support particles comprises an activated carbon particle. It should be understood that the ion exchange resin particles and the activated carbon particles act as both supports and adsorbents because they both possess functional chemicals for adsorption. For example, ion exchange resin particles form large particles with internal pores, primarily for increasing the capacity to adsorb molecules. Activated carbon particles also have internal pores that function in the same manner.

[0018] In one or more embodiments, the diameter of the fine particles is less than 100 µm or micrometer. In one or more embodiments, the diameter of the fine particles is less than 50 µm. In one or more embodiments, the diameter of the fine particles is less than 10 µm. In one or more embodiments, the diameter of the fine particles is less than 1 µm.

[0019] In one or more embodiments, the fine particles comprise rare earth minerals. In one or more embodiments, the fine particles comprise molecules.

[0020] A second aspect of the present invention provides a method for separating fine particles from gangue particles in a slurry, the method comprising: A first fluidized bed with a first fluidizing fluid is generated; Add carrier particles to the slurry; In the coalescence zone of the first fluidized bed, the carrier particles are mixed with the slurry, so that the fine particles adhere to the carrier particles to form aggregates; Separate the aggregates from the gangue particles; A first underflow, comprising aggregates, is removed from a first fluidized bed; A second fluidized bed with a second fluidizing fluid is generated; The first underflow is transferred to the second fluidized bed; The aggregates were separated into fine particles and carrier particles; Removal of a second underflow comprising carrier particles from a second fluidized bed; and Recycle fine particles.

[0021] In one or more embodiments, the method includes adjusting the pH of the fluidizing fluid in the second fluidized bed to a different pH than that of the fluidizing fluid in the first fluidized bed. In one or more embodiments, the method includes adjusting the pH of the fluidizing fluid in the second particle separator to a higher pH than that of the fluidizing fluid in the first particle separator. Alternatively, in one or more embodiments, the method includes adjusting the pH of the fluidizing fluid in the second particle separator to a lower pH than that of the fluidizing fluid in the first particle separator.

[0022] In one or more embodiments, fine particles are separated from carrier particles using multiple inclined channels located in a second fluidized bed.

[0023] In one or more embodiments, a plurality of inclined channels are used to separate the aggregates from the gangue particles, the inclined channels being located above the agglomeration zone in a first fluidized bed.

[0024] In one or more embodiments, the second fluidizing fluid promotes the separation of fine particles from the carrier particles. In one or more embodiments, the method includes adjusting the pH of the second fluidizing fluid to a different pH than that of the first fluidizing fluid to promote the separation of fine particles from the carrier particles. In one or more embodiments, the method includes adjusting the pH of the second fluidizing fluid to a lower pH than that of the first fluidizing fluid to promote the separation of fine particles from the carrier particles. Alternatively, in one or more embodiments, the method includes adjusting the temperature of the second fluidizing fluid to a different temperature than that of the first fluidizing fluid to promote the separation of fine particles from the carrier particles.

[0025] In one or more embodiments, the method includes premixing the slurry and carrier particles before feeding them into a first fluidized bed.

[0026] In one or more embodiments, the method includes recycling the second underflow to the first fluidized bed. In one or more embodiments, the method includes recycling the second underflow to a premixing step.

[0027] In one or more embodiments, the method includes removing gangue particles as a first overflow and dehydrating the first overflow to separate the gangue particles from the fluidizing fluid. In one or more embodiments, the method includes recirculating the fluidizing fluid to a first fluidized bed.

[0028] In one or more embodiments, the method includes recovering fine particles as a second overflow and dehydrating the second overflow to separate the fine particles from the fluidizing fluid. In one or more embodiments, the method includes recirculating the fluidizing fluid to a second fluidized bed.

[0029] In one or more embodiments, the method includes preparing carrier particles by combining coarse-sized particles with one or more adsorbent particles.

[0030] One or more embodiments of the second aspect may, where applicable, have the features of one or more embodiments of the first aspect of the present invention described above.

[0031] Unless the context explicitly requires otherwise, the words “comprising” and “including” should be interpreted inclusively rather than exclusively or exhaustively throughout the specification and claims; that is, “including but not limited to”.

[0032] Furthermore, as used herein, and unless otherwise stated, the ordinal adjectives “first,” “second,” and “third” used to describe the same object simply indicate that they refer to different instances of similar objects and are not intended to imply that the objects being described must be in a particular order in time, space, hierarchy, or any other respect. Attached Figure Description

[0033] Preferred embodiments of the invention will now be described with reference to the accompanying drawings and by way of example only, wherein: Figure 1 This is a schematic diagram of a system according to an embodiment of the present invention. Detailed Implementation

[0034] The invention will now be described with reference to the following examples, which should be considered illustrative in all respects and not restrictive. Although the invention has been described with reference to specific examples, those skilled in the art will understand that the invention may be embodied in many other forms. In the drawings, corresponding features common in the same or different embodiments have been labeled with the same reference numerals.

[0035] Reference Figure 1 The diagram illustrates a system 10 for separating fine particles from gangue particles in a slurry according to an embodiment of the present invention. The system has a first particle separator 100 and a second particle separator 200.

[0036] The first particle separator 100 includes a first container 110 having a first inlet 115 for receiving slurry and carrier particles. A first fluidizing device 120 at one end 130 of the container 110 generates a first fluidized flow 135 of fluidizing fluid and creates a first fluidized bed 140 in the first container. In this embodiment, the end 130 is the base or bottom plate of the container 110. The fluidizing fluid is introduced into the first fluidizing device 120 from a fluidizing source 125 connected to the first fluidizing device via a conduit 128 (e.g., a pipe). The fluidizing fluid is typically water.

[0037] An agglomeration zone 150 is formed within the first fluidized bed 140, allowing fine particles to adhere to the carrier particles and form aggregates. It should be noted that... Figure 1 The coalescing zone 150 shown is for illustrative purposes only and does not necessarily have the shape shown. Instead, the coalescing zone 150 may extend downward to the junction section 155 between the flared section 110a and the throat section 110b of the container 110, and upward below the inclined channel 170 described below. However, the coalescing zone 150 is preferably stationary within the container 110 to reduce the risk of REM particles detaching from the carrier particles. The system 10 also has a first outlet 160 for discharging a first underflow from the container, wherein the first underflow comprises coalesced particles.

[0038] The first particle separator 100 is configured to separate aggregates from gangue particles. In this embodiment, the first particle separator 100 includes a plurality of inclined channels 170 for separating aggregates from gangue particles. Such particle separators with inclined channels are called reflux classifiers, developed by the inventors and described in WO 2008 / 064406, the disclosure of which is incorporated herein by reference in its entirety. Reflux classifiers are powerful devices for separating particles based on particle size and are particularly used in this invention to achieve the separation of aggregates from gangue particles and subsequent separation of carrier particles from fine particles. The inclined channels 170 are located above the agglomeration zone 150.

[0039] The first particle separator 100 includes a feed pipe 180 connected to a first inlet 115 for feeding slurry and carrier particles into the first particle separator. In this embodiment, the feed pipe 180 includes an online mixer (not shown) for pre-mixing the slurry and carrier particles before they are fed into the first particle separator 100. However, in other embodiments, the carrier particles may be added to the slurry before entering the first container 110, without the need for mixing.

[0040] It also includes a first flow channel 185 for receiving gangue particles as overflow. The first flow channel 185 is fluidly connected to a dewatering unit 190 via a pipe 195 for dewatering the overflow to separate the gangue particles from the fluidizing fluid. The fluidizing fluid from the dewatering unit 190 is recycled to the feed pipe 125.

[0041] The second particle separator 200 includes a second container 210 having a second inlet 215 for receiving a first underflow of aggregates from the first particle separator 100. In this embodiment, a conduit 195 and a pump 197 deliver the first underflow from a first outlet 160 to the second inlet 215. A second fluidizing device 220 at one end 230 of the second container 210 generates a second fluidized stream 235 and creates a second fluidized bed 240 within the second container. Similar to the reflux classifier 100, the end 230 is the base or bottom plate of the container 210. A fluidizing fluid is introduced into the second fluidizing device 220 from a fluidizing source 225, which is fluidly connected to the second fluidizing device via a conduit 228 (e.g., a pipe). The fluidizing fluid is a liquid with a different pH level than the fluidizing water used in the first reflux classifier 100.

[0042] The second particle separator 200 is configured to separate the aggregates into fine particles and carrier particles. In this embodiment, the second particle separator 200 further includes a plurality of inclined channels 270 for separating the fine particles from the carrier particles in the aggregates. Therefore, the second particle separator 200 is also a reflux classifier. The inclined channels 270 are located above the fluidized bed 240.

[0043] The second particle separator 200 also has a second outlet 260 for removing a second underflow from container 210. This second underflow includes carrier particles. The second particle separator 200 further has a second flow channel 285 for receiving an overflow containing fine particles. The second flow channel 285 is fluidly connected to a dewatering device 290 via a pipe 300 for separating fine particles from the fluidizing fluid. A reagent such as a flocculant or coagulant 310 can be added to the overflow via pipe 300 to assist the dewatering process. In this embodiment, the dewatering device 290 employs a sedimentation or settling process, wherein fine particles settle to the bottom of the dewatering device and are recovered as sediment 320. The fluidizing fluid from the dewatering device 290 is removed as an overflow via flow channel 330 and recirculated to the second fluidizing device 220 via pipe 340.

[0044] The system also includes a recirculation conduit 350 for recirculating the second underflow to the first particle separator 100. In this embodiment, the recirculation conduit 350 is fluidly connected to the feed conduit 180, and a pump 360 is used to deliver the second underflow of carrier particles to the feed conduit.

[0045] The carrier particles used in this invention have been selected for their high selectivity in attaching to valuable fine mineral particles (especially rare earth minerals or REMs) for recovery from mineral ores, etc. To achieve this high selectivity and recoverability, the invention employs an expanded bed adsorption method and adsorbent in its preferred embodiment.

[0046] Fluidized beds have been used in expanded bed adsorption to recover high-value antibodies from cells. In expanded bed adsorption, antigens are grafted or bound to particulate beads. These beads are then fluidized and allowed to interact with cellular material. Antibodies then selectively attach to the antigens and thus to the beads. The system is then washed to recover the beads, thereby eluting the antibodies.

[0047] To improve capture efficiency, the beads used in expanded bed adsorption need to be relatively large; otherwise, there is a significant risk that these particles will be transported upwards from the fluidized bed and lost. Larger beads also contribute to the creation of a plunger flow process. Given that the product may be intended for human consumption, expanded bed adsorption is typically carried out under batch conditions to ensure greater safety. As a high-value process, batch methods are more effective.

[0048] In the mining and mineral industries, REM particles are typically found in clay derived from mineral ores. These REM particles can range in size from less than 1 micrometer (1 µm) to several micrometers (< 10 µm), or even tens of micrometers (< 50–100 µm). Therefore, the REM particles involved are physically much larger than the molecular structures of antibodies, or much larger than other types of molecules that may be captured by expanded bed adsorption.

[0049] Therefore, the present invention employs a carrier particle in the form of a large or coarse-sized particle, with one or more adsorbent particles attached or bound to it. This large or coarse-sized particle should be significantly larger than the gangue particles in the slurry to ensure a high separation rate or high separation quality in the first particle separator 100. In a preferred embodiment, the system 10 is used to recover REM from clay or mineral materials with a diameter less than 0.05 mm (i.e., 50 µm or micrometer). Therefore, this embodiment employs coarse-sized carrier particles made of silica with a diameter of at least 0.05 mm, preferably at least 0.075 mm, and more preferably at least 0.1 mm. The silica particles should preferably be finer than 0.5 mm, more preferably finer than 0.3 mm. It should be understood that other types of particles may be selected if they do not degrade in response to pH changes (as described below).

[0050] The selected adsorbent is a peptide composed of an amino acid sequence. In embodiments of the present invention, a peptide with sufficiently high selectivity for the REM of interest is preferably used to reduce the amount of peptide required for the process. It is speculated that if this peptide can achieve superior performance compared to… With a recycling efficiency of 99.9%, the economics of using this process to recover REM become extremely attractive. For example, a selectivity coefficient of approximately 1000 and a recycling coefficient of 1000 result in approximately 1000 × 1000 ~ 10 6 The cost advantage of the first level, where the recycling coefficient is 100 / (100- =100 / (100-99.9)=1000.

[0051] In operation, carrier particles are prepared by binding or grafting adsorbed peptides onto silica particles using a polymer film. Ideally, the silica is much coarser than the clay minerals to improve separation quality. Clay and silica / peptide are mixed online in feed line 180 and then fed into a first particle separator or reflux classifier 100 comprising a fluidized bed 140 generated by a fluidized stream 135 from fluidization unit 120. In feed line 180, clusters or aggregates of peptide-bonded silica particles with attached REMs are initially formed, particularly for very fine-sized REMs. Strong aggregation zones 150 provide additional and ample opportunities for loose or unattached REMs to adhere to the peptide-bonded silica particles. Particle attachment is easier because REMs are very small relative to peptide-bonded silica particles. Otherwise, if fine mineral particles are too large relative to peptide-bonded silica particles, they may easily detach or separate. Therefore, from the feed pipe 180 to the coalescence zone 150, clusters or aggregates of these peptide-bonded silica particles with attached REM are continuously formed.

[0052] The reflux classifier 100 has a high feed flow rate, which allows aggregates including peptide-bonded silica particles and attached REM particles to be conveyed into the inclined channel 170, but not so high that the peptide-bonded silica particles are lost and overflow with clay and gangue particles. For a 10 cm × 10 cm container cross-section, the fluidization flow rate can range between 0.2 L / min and 3 L / min. These fluidization flow rates will vary proportionally with the container cross-sectional area. The optimal fluidization flow rate will depend on the particle size distribution of the feed carrier. Generally, a higher fluidization flow rate is required when the carrier particle size distribution is shifted towards larger sizes.

[0053] The inclined channel 170 provides highly efficient and precise separation. The precision is extremely high due to the closely spaced inclined channels (typically spaced at least 6 mm apart). However, in other embodiments, the closely spaced inclined channels are preferably spaced 9 mm apart, or can be spaced in the range of 2 mm to 50 mm. This means that the degree of mixing in the reflux classifier 100 near the outlet point 370 of the inclined channel 170 is negligible. Mixing in the lower part of the fluidized bed 140 is also minimal. Therefore, the chance of losing aggregates (i.e., peptide-bonded silica particles and the fine REM particles attached to them) is extremely low.

[0054] A fluidization velocity slightly above the so-called minimum fluidization velocity is used to promote the movement of agglomerates downwards toward the base 130 through the fluidized bed 140 within container 110. The agglomerates separate from the inclined channel 170 to enter the lower part of the fluidized bed 140. The agglomerates are then discharged from outlet 160 into the first underflow, enter conduit 195, and are pumped by pump 197 to the second reflux classifier 200 for entry via the second inlet 215. Additional water may need to be added to the first underflow so that the feed rate at the second inlet 215 is substantially similar to or the same as the feed rate at the first inlet 115.

[0055] The aggregation zone 150 also defines the intersection of two separation mechanisms: the tilted settling of particles in the tilted channel 170 (which involves almost no mixing) and the tilted settling of the first fluidized flow 135 in the fluidized bed 140 (which also involves very little mixing). In this context, it is desirable to minimize the detachment of REM particles from the peptides attached to the carrier particles. Therefore, system 10 promotes a static state by confining the aggregation zone 150 to a small area.

[0056] Fluidization device 220 generates a second fluidized stream 235, which forms a second fluidized bed 240 in container 210. As described above, the fluidizing fluid comprises a liquid (preferably water) with a different pH value than the fluidizing water in the first reflux classifier 100. The exact pH value depends on the selected peptide, but typically the pH value of the fluidizing water in the second container 210 is less than 7. This is because peptides have strong binding affinity at neutral pH values ​​(i.e., pH=7), but low binding affinity under acidic conditions (less than 7, e.g., pH 4). This pH change causes REM particles to detach from peptide-bound silica particles, thereby breaking down or decomposing the aggregates in the elution zone 250 within the second fluidized bed 240. It should be noted that... Figure 1 The elution zone 250 shown is merely schematic and does not necessarily have the shape shown. Instead, the elution zone 250 may extend through the container 210 and fluidized bed 240, from the fluidizing apparatus 220 along the throat section 210b of the container, through the flared section 210a and the junction section 255 between the throat and flared sections, upward and including an inclined channel 270. Due to their small size, the stripped or released fine REM particles are conveyed upward by the fluidizing flow 235 and collected as overflow by the channel 285.

[0057] The overflow is conveyed through pipe 300 to dewatering unit 290. Flocculant or coagulant 310 is added to the overflow in pipe 300 to promote agglomeration between REM particles, followed by dewatering. In dewatering unit 290, the REM particles flocculate or coagulate and separate from the fluidized liquid. Subsequently, the REM particles settle to the bottom and form sediment 320, which is then recovered. The fluidized liquid is then collected by trough 330 and recirculated through pipe 340 to second return classifier 200. The fluidized liquid can be directly recirculated to return container 210, to pipe 228, or to second fluidization source 225. Alternatively, the fluidized liquid can be used as an additional fluid flow to second inlet 215 to increase the feed flow rate.

[0058] Other stimuli can be applied to help release REM particles from peptide-bonded silica particles, such as by utilizing temperature changes in the fluidizing water in the second classifier 200. However, it is preferable to change the pH of the fluidizing water because this method is easier to implement and requires no additional equipment (e.g., heating systems), thus avoiding increased capital and maintenance costs as well as increased energy consumption.

[0059] After the aggregates break down, the peptide-bonded silica particles move downwards towards the base 230 of container 210 in a plug flow manner, where they are removed as a second underflow via the second outlet 260. This second underflow is then returned or recirculated to the first reflux classifier 100 via a second reflux added to the feed line 180 via a recirculation line 350 and a pump 360. Since the second underflow may contain acidic liquid, it needs to be neutralized (pH 7) before being added to the feed slurry. Typically, 99.9% of the peptide-bonded silica particles in system 10 are recycled. However, to maintain performance, some silica particles may need to be removed and replaced with fresh silica material. Due to the recyclability of the peptide-bonded silica particles in system 10, this replacement rate is very low.

[0060] The first overflow from the first reflux classifier is conveyed via conduit 195 to a dewatering unit 190 to recover process water (i.e., fluidized bed water). In this embodiment, the dewatering unit is a concentrator. The first overflow should generally be neutral (pH 7), but for certain peptides, the pH of the first overflow may be higher or lower. In these cases, the first overflow may need to be neutralized before reuse as process water or fluidized bed water. In some embodiments, the first overflow may be recycled back to the fluidization unit 120 of the first reflux classifier 100 and / or the fluidization unit 220 of the second reflux classifier 200.

[0061] While preferred embodiments of the invention have been described for the recovery of REM molecules from mineral ores and slurries, it should be understood that system 10 can be used to recover specific valuable molecules from liquids. Therefore, the invention can be applied to the recovery of particles and molecules, and even to bubbles or droplets.

[0062] System 10 is also envisioned to perform ion exchange based on a continuous steady-state principle. In this embodiment, ion exchange resin particles are used as carrier particles, and their size may be similar to that of silica particles. As described above, the ion exchange resin particles are mixed with the incoming liquid and fluidized and recovered within system 10. The ion exchange resin particles naturally bind to the target particles through the internal pores of the resin particles, rather than grafting the adsorbent onto the outer surface of the resin particles. Therefore, ion exchange resin particles are better suited for capturing finer particles, most likely molecules (i.e., at the molecular level). Alternatively, activated carbon particles can be used as carrier particles. Activated carbon particles also include internal pores for adsorption, thus eliminating the need for adsorbent particles to adhere to their outer surfaces. Adsorption processes are generally easy to perform, while elution is more difficult, as this may require increased temperatures and the use of alternative liquids.

[0063] In practical applications, ion exchange resins are typically used in a batch operation mode, with liquid flowing downwards through a fixed bed of ion exchange resin particles. In this application of the invention, the fluidized bed allows particulate contaminants to be eluted, while the fixed bed (as used in conventional ion exchange processes) can become clogged when the feed liquid contains fine particles. Therefore, applying system 10 to ion exchange has significant advantages over conventional batch processing methods for ion exchange, especially in terms of higher production efficiency, self-cleaning capabilities, and greater automation.

[0064] The system 10 in this embodiment of the invention can also be used for downstream processing after leaching rare earth metals or elements into a solution. In this case, multiple REMs or rare earth elements can be recovered, so multiple systems 10 can exist, which are used to selectively recover each individual REM or element each time. Thus, each system 10 will serve as an independent stage to recover a specific REM or element.

[0065] Furthermore, it will be understood that any features in the preferred embodiments of the invention can be combined with each other and need not be applied independently. For example, one or both of the particle separators 100 and 200 may be different from each other, although it is preferred that they are both reflux classifiers. Those skilled in the art can readily make similar combinations of two or more features from the above embodiments or preferred forms of the invention.

[0066] Through the aforementioned system and method, this invention provides an efficient and economical way to recover REM from slurry, with less chemical consumption and minimal environmental impact. The particle separator, employing reflux classifiers 100 and 200, captures REM by using flow rate adsorbent-attached carrier particles, enabling expanded bed adsorption and elution technology to operate in a continuous, steady-state manner. Chemical consumption is reduced because the adsorbent-attached carrier particles are more efficient and effective in recovering REM particles. This efficiency is further enhanced by using fluidizing fluids with different pH values ​​in the particle separator to induce the detachment of fine REM particles from the adsorbent-attached carrier particles. This invention also provides for the recovery and recycling of almost all adsorbent-attached carrier particles, allowing the use of more expensive adsorbents that are economically viable for highly selective REM extraction from ore. This precise control over the recycling of adsorbent-attached carrier particles ensures that these particles are not carried away and lost in the overflow. Furthermore, the static conditions of the first reflux classifier 100 help retain larger REM particles on the carrier particles. In the second reflux classifier 200, pH changes promote the natural release of REM to be discharged into the overflow. Recycling the peptide attachment carrier particles from the particle separator significantly minimizes the net cost of typically expensive peptides. The high selectivity of the selected peptides not only minimizes their net cost but also reduces downstream processing costs due to higher REM concentrations. Fluid recycling also minimizes the release of chemicals into the environment, reducing the cost of mitigating and managing these environmental impacts. In all these respects, the present invention represents a practical and commercially significant improvement over the prior art.

Claims

1. A system for separating fine particles from gangue particles in a slurry, comprising: A first particle separator, comprising: The first container has a first inlet for receiving the slurry and carrier particles; A first fluidizing device, located at one end of the container, is used to generate a first fluidized flow of fluidizing fluid and to create a first fluidized bed in the first container, wherein an agglomeration zone is formed within the first fluidized bed, such that the fine particles adhere to the carrier particles to form aggregates; and A first outlet is provided for removing a first underflow from the container, wherein the first underflow comprises the aggregate; Wherein, the first particle separator is configured to separate the aggregates from the gangue particles; and A second particle separator is configured to separate the aggregates into the fine particles and the carrier particles, the second particle separator comprising: The second container has a second inlet for receiving the first underflow from the first particle separator; A second fluidizing device, located at one end of the second container, is used to generate a second fluidizing flow of fluidizing fluid to break up the aggregates and create a second fluidized bed in the second container; A second outlet is provided for removing a second underflow from the second container, wherein the second underflow comprises the carrier particles; and The second flow channel is used to receive the overflow including the fine particles.

2. The system according to claim 1, wherein, The second particle separator includes a plurality of inclined channels for separating the fine particles from the carrier particles, and / or wherein the first particle separator includes a plurality of inclined channels for separating the aggregates from the gangue particles, the inclined channels being located above the agglomeration zone.

3. The system according to claim 1 or 2, wherein, The pH value of the fluidizing fluid in the second particle separator is different from that of the fluidizing fluid in the first particle separator, so as to promote the separation of the fine particles from the carrier particles.

4. The system according to claim 3, wherein, The pH value of the fluidizing fluid in the second particle separator is lower than the pH value of the fluidizing fluid in the first particle separator.

5. The system according to claim 1 or 2, wherein, The temperature of the fluidizing fluid in the second particle separator is different from the temperature of the fluidizing fluid in the first particle separator, so as to promote the separation of the fine particles from the carrier particles.

6. The system according to any one of the preceding claims, wherein, The feed pipe is connected to the first inlet for feeding the slurry and carrier particles into the first particle separator. The feed pipe includes an online mixer for premixing the slurry and carrier particles before feeding them into the first particle separator.

7. The system according to claim 6, wherein, The recirculation pipe is fluidly connected to the feed pipe for recirculating the second underflow to the first particle separator.

8. The system according to any one of claims 1 to 5, comprising a recirculation conduit for recirculating the second underflow to the first particle separator.

9. The system according to any one of the preceding claims, wherein: The first particle separator includes a first flow channel for receiving the gangue particles, the first flow channel being fluidly connected to a dewatering device for separating the gangue particles from the fluidizing fluid, wherein the fluidizing fluid is recycled to the first container; and / or The second flow channel is fluidly connected to a dewatering device for separating the fine particles from the fluidizing fluid, wherein the fluidizing fluid is recycled to the second fluidizing device.

10. The system according to any one of the preceding claims, wherein, Each of the carrier particles includes at least one of the following: coarse-sized particles combined with one or more adsorbent particles; ion exchange resin particles; and activated carbon particles.

11. The system according to claim 10, wherein, The one or more adsorbent particles include peptides.

12. A method for separating fine particles from gangue particles in a slurry, the method comprising: A first fluidized bed with a first fluidizing fluid is generated; Add carrier particles to the slurry; In the coalescence zone of the first fluidized bed, the carrier particles are mixed with the slurry, so that the fine particles adhere to the carrier particles to form aggregates; Separate the aggregates from the gangue particles; Remove the first underflow from the first fluidized bed, the first underflow comprising the aggregate; A second fluidized bed with a second fluidizing fluid is generated; The first underflow is transferred to the second fluidized bed; The aggregate is separated into the fine particles and the carrier particles; Remove a second underflow from the second fluidized bed, the second underflow comprising carrier particles; and The fine particles are recovered.

13. The method according to claim 12, wherein, The fine particles are separated from the carrier particles using multiple inclined channels located in the second fluidized bed, and / or the aggregates are separated from the gangue particles using multiple inclined channels located above the agglomeration zone in the first fluidized bed.

14. The method of claim 12 or 13, further comprising adjusting the pH of the second fluidizing fluid to a different pH than that of the first fluidizing fluid to facilitate the separation of the fine particles from the carrier particles.

15. The method of claim 13, further comprising adjusting the pH of the second fluidizing fluid to be lower than the pH of the first fluidizing fluid.

16. The method of claim 12 or 13, further comprising adjusting the temperature of the second fluidizing fluid to a different temperature than the first fluidizing fluid to induce the fine particles to separate from the carrier particles.

17. The method according to any one of claims 12 to 16, comprising premixing the slurry and the carrier particles before feeding them into the first fluidized bed.

18. The method of claim 17, further comprising recycling the second underflow to the premixing step.

19. The method of claims 12 to 18, further comprising recirculating the second underflow to the first fluidized bed.

20. The method according to any one of claims 12 to 19, comprising: The gangue particles are removed as a first overflow, the first overflow is dehydrated to separate the gangue particles from the fluidized fluid, and the fluidized fluid is recycled to the first fluidized bed; and / or The fine particles are recovered as a second overflow, the second overflow is dehydrated to separate the fine particles from the fluidizing fluid, and the fluidizing fluid is recycled to the second fluidized bed.

21. The method according to any one of claims 12 to 20, comprising preparing the carrier particles by combining coarse-sized particles with one or more adsorbent particles.

22. The method according to claim 21, wherein, The one or more adsorbent particles include peptides.

23. The method according to any one of claims 12 to 20, wherein, Each of the carrier particles includes either ion exchange resin particles or activated carbon particles.

Images