Flotation separation method for bastnaesite and monazite in mixed rare earth concentrate

Abstract

The invention discloses a flotation separation method for bastnaesite and monazite in mixed rare earth concentrate, which is characterized in that the mixed rare earth concentrate is subjected to fluidized roasting under inert gas, so that the bastnaesite in the mixed rare earth concentrate can be quickly converted into cerium fluoride with better flotation performance; the ore phase conversion product containing the cerium fluoride oxide is sequentially subjected to roughing and concentration in a roughing flotation tank and a concentration flotation tank, and roughing monazite concentrate, concentration monazite concentrate and separated cerium fluoride oxide concentrate are obtained; and finally, the roughed monazite concentrate and the concentrated monazite concentrate are added into a scavenging tank for scavenging, separated monazite concentrate is obtained, and separation of the fluocerium oxide concentrate and the monazite concentrate in the ore phase conversion product is completed. According to the separation method provided by the invention, the separation efficiency of the ore phase conversion product can be improved while the consumption of reagents used in the flotation process of the ore phase conversion product is low.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth ore dressing, and in particular relates to a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate. Background Art

[0002] The rare earth reserves in Bayan Obo account for more than 80% of the total reserves in my country. It is a super-large deposit of polymetallic co-existence (associated) such as iron-rare earth-niobium. The main rare earth components are fluorocarbon cerium ore and monazite. The composition of rare earth minerals in Bayan Obo is relatively complex, the ore is finely embedded, and the ore contains a large number of fine-grained minerals. It is difficult to separate the two with traditional mineral processing technology. Therefore, the extraction of rare earth elements in Bayan Obo must be based on mixed rare earth concentrates to formulate metallurgical processes, and concentrated sulfuric acid roasting and caustic soda heating decomposition processes are often used. Due to the large difference in the smelting properties of fluorocarbon cerium ore and monazite, the concentrated sulfuric acid roasting process will produce a large amount of "three wastes" during the production process, which increases the difficulty and cost of treatment and recycling, and causes serious damage to the environment; the caustic soda heating decomposition method has high requirements for rare earth grade, and acid washing and calcium removal are required before alkaline decomposition, which increases energy consumption. In contrast, the concentrate metallurgical process of single fluorocarbon cerium ore or monazite has low energy consumption, simple process and strong adaptability. If these two rare earth minerals can be effectively separated at the source, the metallurgical process can be simplified, energy consumption can be reduced and environmental damage can be minimized.

[0003] Patent 201910060631.1 adopts flotation operations of separation roughing, primary roughing of fluorocarbon cerium ore concentrate and primary roughing of monazite rough concentrate, respectively, to produce high-grade single fluorocarbon cerium ore concentrate and single monazite concentrate. However, the process is complicated and requires separate water washing. For fine particles, it is difficult to use fine screening for classification, and the process does not require the purity of the output fluorocarbon cerium concentrate and monazite concentrate. Patent 202210388995.4 uses a roasting-flotation method to separate fluorocarbon cerium ore and monazite. The roasting temperature of this method is 480~650℃, and the roasting time is 0.5~2 hours. The flotation adopts a process of one roughing, three fines and three sweeps. The added collector is phthalic acid or N-hydroxyphthalimide, the added adjuster is alum or aluminum sulfate, and the added frother is 2 # Oil can be used to obtain single fluorocarbon cerium ore and monazite, but the overall process is complicated, the roasting time is long, the decomposition efficiency is low and the flotation reagent consumption is large.

[0004] In summary, how to provide a separation process of fluorocarbon cerium ore and monazite that can achieve low energy consumption and high recovery rate, and carry out research on enhanced separation of mixed rare earth concentrates, is a technical problem that currently needs to be urgently solved by technical personnel in this field. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps: Step 1: fluidizing and roasting the mixed rare earth concentrate under an inert gas to convert the bastnaesite ore phase in the mixed rare earth concentrate into cerium fluoride oxide to obtain an ore phase conversion product; Step 2: adding the ore phase conversion product to a roughing flotation tank, adding water to prepare a roughing slurry, and then sequentially adding a regulator, a collector and a frother to the roughing slurry for roughing to obtain a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate; Step 3: adding the roughly selected cerium oxyfluoride concentrate to the selected flotation tank, adding water to prepare the selected slurry, and then sequentially adding a regulator, a collector and a frother to the selected slurry for selection, to obtain a selected cerium oxyfluoride concentrate and a selected monazite concentrate, and using the selected cerium oxyfluoride concentrate as the separated cerium oxyfluoride concentrate; Step 4: Add the rougher monazite concentrate and the finer monazite concentrate into the scavenging tank, add water to form a scavenging slurry, and then add a regulator, a collector and a frother to the scavenging slurry in sequence for scavenging to obtain the separated monazite concentrate.

[0007] Optionally, the step 1 of fluidizing and roasting the mixed rare earth concentrate under an inert gas to transform the mixed rare earth concentrate into a mineral phase to obtain a mineral phase transformation product comprises the following steps: Step 101: continuously introducing an inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and using the inert gas as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the inert gas introduced into the quartz tube is 500 mL / min; Step 102: placing the quartz tube into a roasting furnace, and fluidizing and roasting the mixed rare earth concentrate at a temperature of 550-750° C. for 15-45 min to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 103: Cool the mixed rare earth concentrate that has undergone mineral phase transformation to 20-50° C. under an inert gas to obtain a mineral phase transformation product.

[0008] Optionally, the mixed rare earth concentrate is fluidized roasted at a temperature of 700-750° C. for 15-20 min to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate.

[0009] Optionally, in step 2, the pH value of the slurry is 3-5, the amount of the adjusting agent added is 2-3 kg / t, the amount of the collecting agent added is 0.5-2 kg / t, and the amount of the frother added is 0.1-0.3 kg / t.

[0010] Optionally, in step 3, the rough selected cerium oxyfluoride concentrate is added to a selected flotation tank, water is added to form a selected ore pulp, and then a regulator, a collector and a frother are sequentially added to the selected ore pulp for selection to obtain a selected cerium oxyfluoride concentrate and a selected monazite concentrate, comprising the following steps: Step 301: adding the roughly selected cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and adding water to form a first concentrating pulp with a concentration of 25% to 32%; Step 302: adding a conditioning agent, a collecting agent and a frother to the first concentrated slurry in sequence to perform primary concentration, obtaining a primary concentrated foam product and a primary concentrated tank bottom product, and returning the primary concentrated tank bottom product to the roughing tank as a concentrated monazite concentrate; Step 303: adding the primary concentration foam product to the second-stage concentration flotation tank, and adding water to form a second concentration pulp with a concentration of 25% to 32%; Step 304: adding a regulator, a collector and a frother to the second concentrated slurry in sequence for secondary concentration to obtain a secondary concentration foam product and a secondary concentration tank bottom product, and using the secondary concentration foam product as the separated cerium oxyfluoride concentrate; Step 305: The secondary concentration tank bottom product is used as the concentrated monazite concentrate and returned to the first-stage concentration flotation tank.

[0011] Optionally, in step 302 and step 304, the amount of the adjusting agent added is 0.5-1.7 kg / t, the amount of the collecting agent added is 0.15-1.2 kg / t, and the amount of the frother added is 0.05-0.2 kg / t; the slurry temperature of the first concentrated slurry in step 301 and the second concentrated slurry in step 303 are both 20-35°C and the pH value is 3-5.

[0012] Optionally, in step 4, the rougher monazite concentrate and the finer monazite concentrate are added to a scavenging tank, water is added to form a scavenging pulp, and then a regulator, a collector and a frother are sequentially added to the scavenging pulp for scavenging, which comprises the following steps: Step 401: adding the rougher monazite concentrate and the finer monazite concentrate to the first-stage scavenging tank, and adding water to prepare a first scavenging pulp with a concentration of 25% to 30%; Step 402: adding a conditioning agent, a collecting agent and a frother to the first scavenged slurry in sequence to perform a primary scavenging to obtain a primary scavenging foam product and a primary scavenging tank bottom product, and returning the primary scavenging foam product to the roughing tank; Step 403: adding the product from the bottom of the primary scavenging tank to the secondary scavenging tank, and adding water to form a second scavenging pulp with a concentration of 25% to 30%; Step 404: adding a conditioning agent, a collecting agent and a frother to the second scavenging pulp in sequence for secondary scavenging to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and returning the secondary scavenging foam product to the first-stage scavenging tank, and using the secondary scavenging tank bottom product as the separated monazite concentrate.

[0013] Optionally, in step 402 and step 404, the amount of the adjusting agent added is 0.3-1 kg / t, the amount of the collecting agent added is 0.25-1 kg / t, and the amount of the frother added is 0.05-0.2 kg / t; the slurry temperature of the first scavenging slurry in step 401 and the second scavenging slurry in step 403 are both 20-35°C and the pH value is 3-5.

[0014] Optionally, the rare earth oxide REO grade in the mixed rare earth concentrate is 52%~67%.

[0015] Optionally, the adjusting agents in steps 2 to 4 are all alum or aluminum sulfate, the collecting agents are all phthalic acid, and the foaming agents are all No. 2 oil.

[0016] The present invention provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate. The method comprises the following steps: fluidizing and roasting the mixed rare earth concentrate under an inert gas to rapidly convert the bastnaesite in the mixed rare earth concentrate into cerium oxyfluoride with better flotation performance; the ore phase conversion product containing cerium oxyfluoride is sequentially subjected to roughing and concentrating in a roughing flotation cell and a concentrating flotation cell to obtain a roughing monazite concentrate, a concentrating monazite concentrate, and a separated cerium oxyfluoride concentrate; and finally, the roughing monazite concentrate and the concentrating monazite concentrate are added to a scavenging cell for scavenging to obtain a separated monazite concentrate, thereby completing the separation of the cerium oxyfluoride concentrate and the monazite concentrate in the ore phase conversion product. The separation method provided in the present application not only shortens the roasting time of the mixed rare earth concentrate, but also reduces the consumption of reagents used in the flotation process of the mineral phase conversion product, while improving the sorting efficiency of the mineral phase conversion product, and ultimately can obtain a fluorine cerium concentrate with a recovery rate greater than 92% and a purity greater than 97%, and a monazite concentrate with a recovery rate and purity greater than 90%. In addition, the fluorine cerium concentrate separated by the present method can be directly leached without the need for re-roasting, and the extraction of rare earth elements in Bayan Obo can use a single fluorine cerium concentrate or monazite as a raw material for the smelting process, thereby reducing environmental pollution and production costs.

[0017] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flowchart of a method for flotation separation of bastnaesite and monazite in a mixed rare earth concentrate according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] The present invention provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps: Step 1: fluidizing and roasting the mixed rare earth concentrate under an inert gas to convert the bastnaesite ore phase in the mixed rare earth concentrate into cerium fluoride oxide to obtain an ore phase conversion product; Step 2: adding the ore phase conversion product to a roughing flotation tank, adding water to prepare a roughing slurry, and then sequentially adding a regulator, a collector and a frother to the roughing slurry for roughing to obtain a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate; Step 3: adding the roughly selected cerium oxyfluoride concentrate to the selected flotation tank, adding water to prepare the selected slurry, and then sequentially adding a regulator, a collector and a frother to the selected slurry for selection, to obtain a selected cerium oxyfluoride concentrate and a selected monazite concentrate, and using the selected cerium oxyfluoride concentrate as the separated cerium oxyfluoride concentrate; Step 4: Add the rougher monazite concentrate and the finer monazite concentrate into the scavenging tank, add water to form a scavenging slurry, and then add a regulator, a collector and a frother to the scavenging slurry in sequence for scavenging to obtain the separated monazite concentrate.

[0022] Here, the inert gas may be one or a combination of nitrogen, argon, and helium; the particle size of the mixed rare earth concentrate is 0.038 mm, accounting for 96% of the total weight.

[0023] In step 1, by using a fluidized roasting method with obvious mass transfer and heat transfer effects, the conversion rate of fluorocarbon naesite can be accelerated. At the same time, the cerium oxyfluoride obtained by roasting can be directly used for rare earth leaching without further roasting. Therefore, step 1 provided in this embodiment can open up a new way to further extract rare earth elements from single fluorocarbon naesite or rare earth mixed concentrate; at the same time, by fluidizing the roasting of the mixed rare earth concentrate under inert gas, the fluorocarbon naesite (REFCO 3 ) is directionally converted into cerium oxyfluoride (REOF) which is easier to float. Since the monazite in the mixed rare earth concentrate has stability, no phase change occurs in this step. Therefore, the fluorocarbon cerium ore phase in the mixed rare earth concentrate can be converted into cerium oxyfluoride through step 1, which can facilitate the flotation separation of cerium oxyfluoride and monazite in the ore phase conversion product in the subsequent steps, thereby avoiding the "three wastes" problem caused by concentrated sulfuric acid roasting from the source and reducing environmental pollution.

[0024] Among them, the fluidized roasting reaction of bastnaesite in rare earth concentrate under inert gas is: REFCO 3 →REOF+CO 2 ↑.

[0025] In step 2, after roughing the roughing slurry with the adjusting agent, the collecting agent and the frother, a roughing foam product and a roughing tank bottom product can be obtained, wherein the roughing foam product is a primary roughing cerium oxyfluoride concentrate, and the roughing tank bottom product is a primary roughing monazite concentrate. Therefore, by roughing the roughing slurry with the adjusting agent, the collecting agent and the frother, the flotation of the cerium oxyfluoride concentrate can be achieved, and then the primary roughing separation of the cerium oxyfluoride concentrate and the monazite concentrate can be achieved. Similarly, in step 3, after the selected ore pulp is selected by the adjusting agent, the collector and the frother, a selected foam product and a selected bottom product can be obtained, wherein the selected foam product is the selected cerium oxyfluoride concentrate, and the roughing bottom product is the selected monazite concentrate. Therefore, by selecting the roughing ore pulp by the adjusting agent, the collector and the frother, the flotation of the cerium oxyfluoride concentrate can be achieved, and then the selected separation of the cerium oxyfluoride concentrate and the monazite concentrate can be achieved; finally, after the scavenging ore pulp is scavenged by the adjusting agent, the collector and the frother, a scavenging foam product and a scavenging bottom product can be obtained, wherein the scavenging foam product is the scavenged cerium oxyfluoride concentrate, and the scavenging bottom product is the scavenged monazite concentrate. Therefore, by scavenging the scavenging ore pulp by the adjusting agent, the collector and the frother, the flotation of the cerium oxyfluoride concentrate can be achieved, and then the scavenging separation of the cerium oxyfluoride concentrate and the monazite concentrate can be achieved.

[0026] In this embodiment, by fluidizing roasting the mixed rare earth concentrate under inert gas, the fluorocarbon cerium ore in the mixed rare earth concentrate can be quickly converted into cerium oxyfluoride with better flotation performance; the ore phase conversion product containing cerium oxyfluoride is then subjected to roughing and concentrating in a roughing flotation cell and a concentrating flotation cell in sequence to obtain a roughing monazite concentrate, a concentrating monazite concentrate, and a separated cerium oxyfluoride concentrate; finally, the roughing monazite concentrate and the concentrating monazite concentrate are added to a scavenging cell for scavenging to obtain a separated monazite concentrate, thereby completing the separation of the cerium oxyfluoride concentrate and the monazite concentrate in the ore phase conversion product. The separation method provided in the present application not only shortens the roasting time of the mixed rare earth concentrate, but also reduces the consumption of reagents used in the flotation process of the mineral phase conversion products, while improving the sorting efficiency of the mineral phase conversion products, and ultimately can obtain a cerium fluoride concentrate with a recovery rate greater than 92% and a purity greater than 97%, and a monazite concentrate with a recovery rate and purity greater than 90%. In addition, the cerium fluoride concentrate separated by the present method can be directly leached without the need for re-roasting, and the Bayan Obo rare earth element extraction can use a single cerium fluoride concentrate or monazite as a raw material for the smelting process, thereby reducing environmental pollution and production costs.

[0027] In some possible embodiments, the step 1 of fluidizing and roasting the mixed rare earth concentrate under an inert gas to transform the mixed rare earth concentrate into a mineral phase to obtain a mineral phase transformation product comprises the following steps: Step 101: continuously introducing an inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and using the inert gas as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the inert gas introduced into the quartz tube is 500 mL / min; Step 102: placing the quartz tube into a roasting furnace, and fluidizing and roasting the mixed rare earth concentrate at a temperature of 550-750° C. for 15-45 min to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 103: Cool the mixed rare earth concentrate that has undergone mineral phase transformation to 20-50° C. under an inert gas to obtain a mineral phase transformation product.

[0028] It should be noted that, in step 102, before placing the quartz tube into the roasting furnace, the roasting furnace is heated to a preset temperature before placing the quartz tube into the roasting furnace.

[0029] In step 101, by continuously introducing an inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and using the inert gas as a fluidizing gas, the mixed rare earth concentrate can be kept in a fluidized state, and the exhaust of the air in the quartz tube can prevent the oxidation of fluorocarbon cerium ore and the cerium oxyfluoride obtained by its mineral phase transformation. In step 102, during the fluidized roasting process of the mixed rare earth concentrate, the mixed rare earth concentrate is always kept in an inert gas atmosphere for roasting reaction to avoid oxidation of fluorocarbon cerium ore and its mineral phase transformation products. In addition, in step 103, by cooling the mineral phase transformed mixed rare earth concentrate under an inert gas, the problem of generating Ce (IV) with poor floatability caused by oxidation of fluorocarbon cerium ore and its mineral phase transformation products can be avoided.

[0030] In this embodiment, by selecting fluidized roasting with better mass and heat transfer effects, compared with the traditional roasting process, fluorocarbon cerium ore can be quickly decomposed without adding additives, thereby realizing the mineral phase transformation of fluorocarbon cerium ore; at the same time, by using inert gas as fluidizing gas and roasting and cooling the mixed rare earth concentrate under inert gas, not only can fluorocarbon cerium ore be quickly and directionally converted into cerium oxyfluoride, but also the problem of generating Ce(IV) with poor floatability due to oxidation of fluorocarbon cerium ore and its mineral phase transformation products can be avoided.

[0031] In some possible embodiments, the mixed rare earth concentrate is fluidized roasted at a temperature of 700-750° C. for 15-20 min to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate.

[0032] Here, when the mixed rare earth concentrate is fluidized roasted at a temperature of 700-750°C for 15-20 min, the bastnaesite phase conversion rate in the mixed rare earth concentrate is fast and the conversion rate is high. Therefore, the fluidized roasting temperature of the mixed rare earth concentrate is selected as 700-750°C, and the roasting time is selected as 15-20 min. Of course, the corresponding ranges of the fluidized roasting temperature and roasting time are determined by the inventor through a large number of experiments, and the performance is optimized while fully reducing the cost by controlling them within an appropriate range.

[0033] In this embodiment, the mixed rare earth concentrate is fluidized roasted at a temperature of 700-750° C. for 15-20 min to complete the ore phase transformation of bastnaesite in the mixed rare earth concentrate and increase the ore phase transformation rate of bastnaesite.

[0034] In some possible embodiments, the pH value of the slurry in step 2 is 3-5, the amount of the adjusting agent added is 2-3 kg / t, the amount of the collecting agent added is 0.5-2 kg / t, and the amount of the frother added is 0.1-0.3 kg / t.

[0035] Here, the pH value of the slurry in step 2 can be, but is not limited to, 3, 3.5, 4, 4.5, and 5; the amount of the adjusting agent added in step 2 can be, but is not limited to, 2.2 kg / t, 2.4 kg / t, 2.6 kg / t, 2.8 kg / t, and 3 kg / t; the amount of the collector added in step 2 can be, but is not limited to, 0.5 kg / t, 0.8 kg / t, 1.1 kg / t, 1.4 kg / t, 1.7 kg / t, and 2 kg / t; the amount of the frother added in step 2 can be, but is not limited to, 0.1 kg / t, 0.15 kg / t, 0.2 kg / t, 0.25 kg / t, and 0.3 kg / t.

[0036] In some possible embodiments, the step 3 adds the rough cerium oxyfluoride concentrate to a concentrated flotation tank, adds water to form a concentrated slurry, and then sequentially adds a regulator, a collector and a frother to the concentrated slurry for concentration, thereby obtaining a concentrated cerium oxyfluoride concentrate and a concentrated monazite concentrate, comprising the following steps: Step 301: adding the roughly selected cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and adding water to form a first concentrating pulp with a concentration of 25% to 32%; Step 302: adding a conditioning agent, a collecting agent and a frother to the first concentrated slurry in sequence to perform primary concentration, obtaining a primary concentrated foam product and a primary concentrated tank bottom product, and returning the primary concentrated tank bottom product to the roughing tank as a concentrated monazite concentrate; Step 303: adding the primary concentration foam product to the second-stage concentration flotation tank, and adding water to form a second concentration pulp with a concentration of 25% to 32%; Step 304: adding a regulator, a collector and a frother to the second concentrated slurry in sequence for secondary concentration to obtain a secondary concentration foam product and a secondary concentration tank bottom product, and using the secondary concentration foam product as the separated cerium oxyfluoride concentrate; Step 305: The secondary concentration tank bottom product is used as the concentrated monazite concentrate and returned to the first-stage concentration flotation tank.

[0037] It should be noted that in step 302: the primary concentrating foam product is the primary concentrating cerium oxyfluoride concentrate, and the primary concentrating bottom product is the concentrating monazite concentrate; in step 304: the secondary concentrating foam product is the secondary concentrating cerium oxyfluoride concentrate, and the secondary concentrating bottom product is the concentrating monazite concentrate; therefore, the primary concentrating bottom product is returned to the roughing tank as the concentrating monazite concentrate, so that the concentrating monazite concentrate can be used for flotation separation of cerium oxyfluoride and monazite in the mixed rare earth concentrate ore phase conversion product in the next time. In step 305, because the secondary concentrating tank bottom product is the concentrating monazite concentrate, in order to separate the monazite concentrate from the cerium oxyfluoride concentrate, the secondary concentrating tank bottom product is returned to the first-stage concentrating flotation tank, so that the secondary concentrating flotation tank bottom product can be returned to the roughing tank along with the primary concentrating tank bottom product in the first-stage concentrating flotation tank, and the secondary concentrating tank bottom product can be added from the roughing tank to the scavenging tank, thereby completing the scavenging of the secondary concentrating tank bottom product in the scavenging tank.

[0038] In this embodiment, the roughing cerium fluoride oxide concentrate is added to the first-stage concentration flotation tank to complete the primary concentration of the roughing cerium fluoride oxide concentrate, and the obtained primary concentration tank bottom product is returned to the roughing tank as the concentrated monazite concentrate; then, the obtained primary concentration foam product is added to the second-stage concentration flotation tank to complete the secondary concentration of the cerium fluoride oxide concentrate, and the secondary concentration foam product is used as the concentrated cerium fluoride oxide concentrate, and the obtained secondary concentration tank bottom product is returned to the first-stage concentration flotation tank, thereby realizing the secondary concentration of the roughing cerium fluoride oxide concentrate to obtain a cerium fluoride oxide concentrate with higher purity, and the primary concentration tank bottom product and the secondary concentration tank bottom product separated in the process of concentrating the roughing cerium fluoride oxide concentrate can be returned to the roughing tank and the first-stage concentration tank respectively, so that the primary concentration tank bottom product and the secondary concentration tank bottom product can be added to the scavenging tank for scavenging separation, so as to improve the recovery rate of monazite.

[0039] In some possible embodiments, the amount of the adjusting agent added in step 302 and step 304 is 0.5-1.7 kg / t, the amount of the collecting agent added is 0.15-1.2 kg / t, and the amount of the frother added is 0.05-0.2 kg / t; the slurry temperature of the first concentrated slurry in step 301 and the second concentrated slurry in step 303 is 20-35°C, and the pH value is 3-5.

[0040] Here, the amount of the adjusting agent added in step 302 and step 304 can be, but not limited to, 0.5 kg / t, 0.8 kg / t, 1.1 kg / t, 1.4 kg / t, 1.7 kg / t; the amount of the collecting agent added in step 302 and step 304 can be, but not limited to, 0.15 kg / t, 0.4 kg / t, 0.8 kg / t, 0.10 kg / t, and 1.2 kg / t; the amount of the frother added in step 302 and step 304 can be, but not limited to, 0.05 kg / t, 0.1 kg / t, 0.15 kg / t, and 0.2 kg / t. The slurry temperature of the first concentrated slurry in step 301 and the second concentrated slurry in step 303 can be, but not limited to, 20°C, 25°C, 30°C, and 35°C, and the pH value of the first concentrated slurry in step 301 and the second concentrated slurry in step 303 can be, but not limited to, 3, 3.5, 4, 4.5, and 5.

[0041] In some possible embodiments, the step 4 of adding the rougher monazite concentrate and the finer monazite concentrate to the scavenging tank, adding water to form a scavenging pulp, and then sequentially adding a regulator, a collector and a frother to the scavenging pulp for scavenging includes the following steps: Step 401: adding the rougher monazite concentrate and the finer monazite concentrate to the first-stage scavenging tank, and adding water to prepare a first scavenging pulp with a concentration of 25% to 30%; Step 402: adding a conditioning agent, a collecting agent and a frother to the first scavenged slurry in sequence to perform a primary scavenging to obtain a primary scavenging foam product and a primary scavenging tank bottom product, and returning the primary scavenging foam product to the roughing tank; Step 403: adding the product from the bottom of the primary scavenging tank to the secondary scavenging tank, and adding water to form a second scavenging pulp with a concentration of 25% to 30%; Step 404: adding a conditioning agent, a collecting agent and a frother to the second scavenging pulp in sequence for secondary scavenging to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and returning the secondary scavenging foam product to the first-stage scavenging tank, and using the secondary scavenging tank bottom product as the separated monazite concentrate.

[0042] It should be noted that in step 402: the primary scavenging foam product is the primary scavenging cerium oxyfluoride concentrate, and the primary scavenging tank bottom product is the primary scavenging monazite concentrate; in step 404: the secondary scavenging foam product is the secondary scavenging cerium oxyfluoride concentrate, and the secondary scavenging tank bottom product is the secondary scavenging monazite concentrate; therefore, the primary scavenging foam product is returned to the roughing tank here, so that the primary scavenging foam product can be used in the next flotation separation of cerium oxyfluoride and monazite in the mixed rare earth concentrate ore phase conversion product in the roughing flotation. In step 404: because the secondary scavenging froth product is the secondary scavenging cerium oxide concentrate, in order to separate the monazite concentrate from the cerium oxide concentrate, the secondary scavenging cerium oxide concentrate is returned to the first-stage scavenging tank, so that the secondary scavenging cerium oxide concentrate can be returned to the roughing tank along with the primary scavenging froth product in the first-stage scavenging tank, and the secondary scavenging cerium oxide concentrate can be transferred from the roughing tank to the concentrating flotation tank, thereby completing the concentrating of the secondary scavenging cerium oxide concentrate in the concentrating flotation tank.

[0043] In this embodiment, the roughing monazite concentrate and the concentrated monazite concentrate are added to the first-stage scavenging tank to complete the primary scavenging of the roughing monazite concentrate and the concentrated monazite concentrate, and the obtained primary scavenging foam product is returned to the roughing tank; then, the obtained primary scavenging tank bottom product is added to the second-stage scavenging tank to complete the secondary scavenging of monazite, and the secondary scavenging tank bottom product is used as the separated monazite concentrate, and the obtained secondary scavenging foam product is returned to the first-stage scavenging tank, thereby realizing the double scavenging of the roughing monazite concentrate and the concentrated monazite concentrate, and obtaining a monazite concentrate with higher purity. At the same time, the primary scavenging foam product and the secondary scavenging foam product separated in the scavenging process of the monazite concentrate can be returned to the roughing tank and the first-stage scavenging tank respectively, so that the primary scavenging foam product and the secondary scavenging foam product can be added to the concentrated flotation tank for concentrated separation, so as to improve the recovery rate of cerium fluoride oxide.

[0044] In some possible embodiments, the amount of the adjusting agent added in step 402 and step 404 is 0.3~1 kg / t, the amount of the collecting agent added is 0.25~1 kg / t, and the amount of the frother added is 0.05~0.2 kg / t; the slurry temperature of the first scavenging slurry in step 401 and the second scavenging slurry in step 403 is 20~35°C, and the pH value is 3~5.

[0045] Here, the amount of the adjusting agent added in step 402 and step 404 can be, but not limited to, 0.3 kg / t, 0.5 kg / t, 0.8 kg / t, 1 kg / t; the amount of the collecting agent added in step 402 and step 404 can be, but not limited to, 0.25 kg / t, 0.4 kg / t, 0.8 kg / t, 0.10 kg / t; the amount of the frother added in step 402 and step 404 can be, but not limited to, 0.05 kg / t, 0.1 kg / t, 0.15 kg / t, 0.2 kg / t. The slurry temperature of the first scavenging slurry in step 401 and the second scavenging slurry in step 403 can be, but not limited to, 20°C, 25°C, 30°C, and 35°C, and the pH value of the first scavenging slurry in step 401 and the second scavenging slurry in step 403 can be, but not limited to, 3, 3.5, 4, 4.5, and 5.

[0046] In some possible embodiments, the rare earth oxide REO grade in the mixed rare earth concentrate is 52%~67%.

[0047] Here, the mixed rare earth concentrate can be the Bayan Obo mixed rare earth ore. The REO grade of the Bayan Obo mixed rare earth ore is 50% to 67%. The rare earth minerals it mainly contains are fluorocarbon cerium ore and monazite, among which the F grade is 4% to 10%, and the fluorine-containing minerals are fluorocarbon cerium ore, fluorocarbon calcium cerium ore, and fluorite; the P grade is 4% to 10%, and the phosphorus-containing minerals are monazite and apatite.

[0048] In some possible embodiments, the adjusting agents in steps 2 to 4 are all alum or aluminum sulfate, the collecting agents are all phthalic acid, and the foaming agents are all No. 2 oil.

[0049] In this embodiment, since the regulator, collector and frother used are reagents with little impact on the environment, the separation method used in the present invention can avoid using reagents with great impact on the environment, thereby reducing environmental pollution.

[0050] The following is a specific description of the flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate provided by the present invention through examples. It should be noted that the methods, reagents and materials described in the following examples, unless otherwise specified, can all be obtained from commercial channels; the test methods, unless otherwise specified, are all conventional methods.

[0051] Example 1 The present embodiment provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps: Step 1: nitrogen is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate having a rare earth oxide REO grade of 64.8%, and the nitrogen is used as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the nitrogen introduced into the quartz tube is 500 mL / min; Step 2: placing the quartz tube into a roasting furnace, and fluidizing and roasting the mixed rare earth concentrate at 700° C. for 20 minutes to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 3: Cooling the mixed rare earth concentrate after the mineral phase transformation to 35° C. under nitrogen to obtain a mineral phase transformation product; Step 4: Add the mineral phase conversion product to the roughing flotation tank, add water to make a roughing pulp with a concentration of 33% and a pH value of 4.6, and then add 2.2 kg / t of alum, 1.2 kg / t of phthalic acid and 2 # Oil 0.2 kg / t was used for roughing to obtain roughing cerium oxyfluoride concentrate and roughing monazite concentrate; Step 5: Add the roughly selected cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and add water to form a first concentrating pulp with a concentration of 29% and a pH value of 4.5; Step 6: Add 1.2 kg / t of alum, 0.3 kg / t of phthalic acid and 2 # The oil is 0.15 kg / t and the primary concentrator is used to obtain a primary concentrator foam product and a primary concentrator bottom product, and the primary concentrator bottom product is returned to the roughing tank as a concentrator monazite concentrate; Step 7: Add the primary concentration froth product to the second-stage concentration flotation tank, add water to form a second concentration pulp with a concentration of 27% and a pH value of 4.5; Step 8: Add 0.6 kg / t of alum, 0.2 kg / t of phthalic acid and 2 # Oil 0.1 kg / t is used for secondary concentration to obtain secondary concentration foam product and secondary concentration tank bottom product, and the secondary concentration foam product is used as the separated concentrated cerium oxyfluoride concentrate; Step 9: The secondary concentration tank bottom product is returned to the first-stage concentration flotation tank as the concentrated monazite concentrate; Step 10: Add the rougher monazite concentrate and the finer monazite concentrate to the first scavenging tank, add water to form a first scavenging pulp with a concentration of 27% and a pH value of 4; Step 11: Add 0.7 kg / t of alum, 0.8 kg / t of phthalic acid and 2 #The oil is 0.15 kg / t and a scavenging is performed once to obtain a scavenging foam product and a scavenging tank bottom product, and the scavenging foam product is returned to the roughing tank; Step 12: Add the product from the bottom of the primary scavenging tank to the second-stage scavenging tank, and add water to prepare a second scavenging pulp with a concentration of 27% and a pH value of 4; Step 13: Add 0.4 kg / t of alum, 0.6 kg / t of phthalic acid and 2 # The secondary scavenging is carried out at a concentration of 0.15 kg / t of oil to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and the secondary scavenging foam product is returned to the first-stage scavenging tank, and the secondary scavenging tank bottom product is used as the separated monazite concentrate.

[0052] The purity of the selected cerium oxyfluoride concentrate separated in this example is 97.3%, and the recovery rate is 92.81%; the purity of the separated monazite concentrate is 92.4%, and the recovery rate is 91.19%.

[0053] Example 2 The present embodiment provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps: Step 1: nitrogen is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate having a rare earth oxide REO grade of 53.55%, and the nitrogen is used as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the nitrogen introduced into the quartz tube is 500 mL / min; Step 2: placing the quartz tube into a roasting furnace, and fluidizing and roasting the mixed rare earth concentrate at a temperature of 550° C. for 45 minutes to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 3: Cooling the mixed rare earth concentrate after the mineral phase transformation to 25° C. under nitrogen to obtain a mineral phase transformation product; Step 4: Add the mineral phase conversion product to the roughing flotation tank, add water to make a roughing pulp with a concentration of 35% and a pH value of 4, and then add 3 kg / t of aluminum sulfate, 2 kg / t of phthalic acid and 2 kg / t of phthalic acid to the roughing pulp at a temperature of 30°C. # Oil 0.3 kg / t was used for roughing to obtain roughing cerium oxyfluoride concentrate and roughing monazite concentrate; Step 5: Add the roughly selected cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and add water to prepare a first concentrating pulp with a concentration of 32% and a pH value of 3.5; Step 6: Add 1 kg / t of aluminum sulfate, 0.8 kg / t of phthalic acid and 2 kg / t of phthalic acid to the first concentrated slurry at a temperature of 30°C. #The oil is concentrated once at 0.2 kg / t to obtain a primary concentrated froth product and a primary concentrated flotation tank bottom product, and the primary concentrated flotation tank bottom product is returned to the roughing tank as a concentrated monazite concentrate; Step 7: Add the primary concentration froth product to the second-stage concentration flotation tank, add water to form a second concentration pulp with a concentration of 28% and a pH value of 3.5; Step 8: Add 0.7 kg / t of aluminum sulfate, 0.3 kg / t of phthalic acid and 2 # Oil 0.1 kg / t is used for secondary concentration to obtain secondary concentration foam product and secondary concentration tank bottom product, and the secondary concentration foam product is used as the separated concentrated cerium oxyfluoride concentrate; Step 9: The secondary concentration tank bottom product is returned to the first-stage concentration flotation tank as the concentrated monazite concentrate; Step 10: Add the rougher monazite concentrate and the finer monazite concentrate to the first scavenging tank, add water to form a first scavenging pulp with a concentration of 29% and a pH value of 3.2; Step 11: Add 1 kg / t of aluminum sulfate, 1 kg / t of phthalic acid and 2 kg / t of phthalic acid to the first scavenged slurry at a temperature of 30°C. # The oil is 0.15 kg / t and a scavenging is performed once to obtain a scavenging foam product and a scavenging tank bottom product, and the scavenging foam product is returned to the roughing tank; Step 12: Add the product from the bottom of the primary scavenging tank to the secondary scavenging tank, and add water to prepare the secondary scavenging pulp with a concentration of 29% and a pH value of 3.2; Step 13: Add 0.5 kg / t of aluminum sulfate, 0.8 kg / t of phthalic acid and 2 # The secondary scavenging is carried out at a concentration of 0.15 kg / t of oil to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and the secondary scavenging foam product is returned to the first-stage scavenging tank, and the secondary scavenging tank bottom product is used as the separated monazite concentrate.

[0054] The purity of the selected cerium oxyfluoride concentrate separated in this example is 97%, and the recovery rate is 93.3%; the purity of the separated monazite concentrate is 91.8%, and the recovery rate is 92.3%.

[0055] Example 3 The present embodiment provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps: Step 1: nitrogen is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate having a rare earth oxide REO grade of 60.42%, and the nitrogen is used as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the nitrogen introduced into the quartz tube is 500 mL / min; Step 2: placing the quartz tube into a roasting furnace, and fluidizing and roasting the mixed rare earth concentrate at 650° C. for 30 minutes to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 3: Cooling the mixed rare earth concentrate after the mineral phase transformation to 30° C. under nitrogen to obtain a mineral phase transformation product; Step 4: Add the mineral phase conversion product to the roughing flotation tank, add water to make a roughing pulp with a concentration of 28% and a pH value of 4.6, and then add 2.5 kg / t of aluminum sulfate, 1.4 kg / t of phthalic acid and 2 # Oil 0.25 kg / t was used for roughing to obtain roughing cerium oxyfluoride concentrate and roughing monazite concentrate; Step 5: Add the roughly selected cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and add water to form a first concentrating pulp with a concentration of 28% and a pH value of 4; Step 6: Add 1.3 kg / t of aluminum sulfate, 0.5 kg / t of phthalic acid and 2 # The oil is concentrated once at 0.2 kg / t to obtain a primary concentrated foam product and a primary concentrated tank bottom product, and the primary concentrated tank bottom product is returned to the roughing tank as a concentrated monazite concentrate; Step 7: Add the primary concentration froth product to the second-stage concentration flotation tank, add water to form a second concentration pulp with a concentration of 25% and a pH value of 4; Step 8: Add 0.9 kg / t of aluminum sulfate, 0.25 kg / t of phthalic acid and 2 # The oil is 0.13 kg / t for secondary concentration to obtain secondary concentration foam products and secondary concentration tank bottom products, and the secondary concentration foam products are used as the separated concentrated cerium oxyfluoride concentrate; Step 9: The secondary concentration tank bottom product is returned to the first-stage concentration flotation tank as the concentrated monazite concentrate; Step 10: Add the rougher monazite concentrate and the finer monazite concentrate to the first scavenging tank, add water to form a first scavenging pulp with a concentration of 29% and a pH value of 3.8; Step 11: Add 0.9 kg / t of alum, 0.8 kg / t of phthalic acid and 2 #The oil is 0.2 kg / t and a scavenging is performed once to obtain a scavenging foam product and a scavenging tank bottom product, and the scavenging foam product is returned to the roughing tank; Step 12: Add the product from the bottom of the primary scavenging tank to the second-stage scavenging tank, and add water to prepare a second scavenging pulp with a concentration of 29% and a pH value of 2.8; Step 13: Add 0.6 kg / t of alum, 0.4 kg / t of phthalic acid and 2 # The secondary scavenging is carried out at a concentration of 0.15 kg / t of oil to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and the secondary scavenging foam product is returned to the first-stage scavenging tank, and the secondary scavenging tank bottom product is used as the separated monazite concentrate.

[0056] The purity of the selected cerium oxyfluoride concentrate separated in this example is 97.2%, and the recovery rate is 92.73%; the purity of the separated monazite concentrate is 92%, and the recovery rate is 90.88%.

[0057] Example 4 The present embodiment provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps: Step 1: nitrogen is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate having a rare earth oxide REO grade of 66.73%, and the nitrogen is used as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the nitrogen introduced into the quartz tube is 500 mL / min; Step 2: placing the quartz tube into a roasting furnace, and subjecting the mixed rare earth concentrate to fluidized roasting at 750° C. for 15 minutes to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 3: Cooling the mixed rare earth concentrate after the mineral phase transformation to 40° C. under nitrogen to obtain a mineral phase transformation product; Step 4: Add the mineral phase conversion product to the roughing flotation tank, add water to make a roughing pulp with a concentration of 30% and a pH value of 5, and then add 2 kg / t of alum, 0.8 kg / t of phthalic acid and 2 kg / t of phthalic acid to the roughing pulp at a temperature of 25°C. # Oil 0.1 kg / t was used for roughing to obtain roughing cerium oxyfluoride concentrate and roughing monazite concentrate; Step 5: Add the roughly selected cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and add water to form a first concentrating pulp with a concentration of 29% and a pH value of 4.6; Step 6: Add 1 kg / t alum, 0.2 kg / t phthalic acid and 2 kg / t to the first concentrated slurry at a temperature of 25°C. #The oil is 0.15 kg / t and the primary concentrator is used to obtain a primary concentrator foam product and a primary concentrator bottom product, and the primary concentrator bottom product is returned to the roughing tank as a concentrator monazite concentrate; Step 7: Add the primary concentration froth product to the second-stage concentration flotation tank, add water to form a second concentration pulp with a concentration of 28% and a pH value of 4.6; Step 8: Add 0.5 kg / t of alum, 0.15 kg / t of phthalic acid and 2 # Oil 0.05 kg / t for secondary concentration, to obtain secondary concentration foam product and secondary concentration tank bottom product, and the secondary concentration foam product is used as the separated concentrated cerium fluoride concentrate; Step 9: The secondary concentration tank bottom product is returned to the first-stage concentration flotation tank as the concentrated monazite concentrate; Step 10: Add the rougher monazite concentrate and the finer monazite concentrate to the first scavenging tank, add water to form a first scavenging pulp with a concentration of 29% and a pH value of 4.5; Step 11: Add 0.5 kg / t of alum, 0.4 kg / t of phthalic acid and 2 # The oil is 0.1 kg / t and a scavenging process is performed to obtain a scavenging foam product and a scavenging tank bottom product, and the scavenging foam product is returned to the roughing tank; Step 12: Add the product from the bottom of the primary scavenging tank to the secondary scavenging tank, and add water to prepare the secondary scavenging pulp with a concentration of 27% and a pH value of 4.5; Step 13: Add 0.3 kg / t of alum, 0.25 kg / t of phthalic acid and 2 # The secondary scavenging is carried out at a concentration of 0.05 kg / t of oil to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and the secondary scavenging foam product is returned to the first-stage scavenging tank, and the secondary scavenging tank bottom product is used as the separated monazite concentrate.

[0058] The purity of the selected cerium oxyfluoride concentrate separated in this example is 97.8%, and the recovery rate is 94.2%; the purity of the separated monazite concentrate is 90.7%, and the recovery rate is 92.2%.

[0059] Comparative Example 1 Relative to Example 1, the flotation separation method of fluorocarbon cerium ore and monazite in a mixed rare earth concentrate provided in this embodiment is basically the same as the preparation method provided in Example 1, with the difference that: the mixed rare earth concentrate does not undergo step 2 and step 3, that is, the fluorocarbon cerium is not subjected to a mineral phase conversion process, and the mixed rare earth concentrate is not subjected to an inert cooling process, but the mixed rare earth concentrate in step 1 is directly added to a roughing flotation tank for roughing separation, and the other steps and the process parameters involved remain unchanged.

[0060] The purity of the selected cerium fluoride oxide concentrate separated in this comparative example is 88.72%, and the recovery rate is 84.2%; the purity of the separated monazite concentrate is 81.38%, and the recovery rate is 82.7%.

[0061] Comparative Example 2 Relative to Example 1, the flotation separation method of fluorocarbon cerium ore and monazite in a mixed rare earth concentrate provided in this embodiment is basically the same as the preparation method provided in Example 1, with the difference that: the nitrogen involved in step 1 and step 2 is replaced by air, that is, the mixed rare earth concentrate is fluidized roasted with air as the fluidizing gas, and the other steps and the process parameters involved remain unchanged.

[0062] The purity of the selected cerium fluoride oxide concentrate separated in this comparative example is 90.44%, and the recovery rate is 85.56%; the purity of the separated monazite concentrate is 83.77%, and the recovery rate is 80.62%.

[0063] Comparative Example 3 Relative to Example 1, the flotation separation method of fluorocarbon cerium ore and monazite in a mixed rare earth concentrate provided in this embodiment is basically the same as the preparation method provided in Example 1, with the difference that: the nitrogen involved in step 3 is replaced by air, that is, the mixed rare earth concentrate that has undergone ore phase transformation is cooled under air gas, and the other steps and the process parameters involved remain unchanged.

[0064] The purity of the selected cerium fluoride oxide concentrate separated in this comparative example is 91.69%, and the recovery rate is 88.65%; the purity of the separated monazite concentrate is 84.44%, and the recovery rate is 81.79%.

[0065] It can be seen from the above-mentioned examples and comparative examples that the flotation separation method adopted in the present invention can well separate fluorocarbon cerium ore and monazite in the mixed rare earth concentrate, and the separated cerium fluoride oxide does not need to be roasted again and can be directly leached, thus opening up a new way to extract rare earth elements from mixed rare earth concentrates.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, characterized in that: The steps include: Step 1: fluidizing and roasting the mixed rare earth concentrate under an inert gas to convert the bastnaesite ore phase in the mixed rare earth concentrate into cerium oxyfluoride to obtain an ore phase conversion product; Step 2: adding the mineral phase conversion product to a roughing flotation tank, adding water to prepare a roughing pulp, and then sequentially adding a regulator, a collector and a frother to the roughing pulp for roughing to obtain a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate; Step 3: adding the rough selected cerium oxyfluoride concentrate to a selected flotation tank, adding water to prepare a selected ore pulp, and then sequentially adding a regulator, a collector and a frother to the selected ore pulp for selection, to obtain a selected cerium oxyfluoride concentrate and a selected monazite concentrate, and using the selected cerium oxyfluoride concentrate as the separated cerium oxyfluoride concentrate; Step 4: adding the rougher monazite concentrate and the finer monazite concentrate into a scavenging tank, adding water to form a scavenging pulp, and then sequentially adding a regulator, a collector and a frother to the scavenging pulp for scavenging to obtain a separated monazite concentrate.

2. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that: The step 1 of fluidizing and roasting the mixed rare earth concentrate under an inert gas to transform the mixed rare earth concentrate into a mineral phase and obtain a mineral phase transformation product comprises the following steps: Step 101: continuously introducing an inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and using the inert gas as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the gas flow rate of the inert gas introduced into the quartz tube is 500 mL / min; Step 102: placing the quartz tube into a roasting furnace, and fluidizing and roasting the mixed rare earth concentrate at a temperature of 550-750° C. for 15-45 min to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate; Step 103: Cooling the mixed rare earth concentrate that has undergone mineral phase transformation to 20-50° C. under an inert gas to obtain the mineral phase transformation product.

3. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that: The mixed rare earth concentrate is fluidized roasted at a temperature of 700-750° C. for 15-20 min to complete the phase transformation of the bastnaesite in the mixed rare earth concentrate.

4. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that: In step 2, the pH value of the slurry is 3-5, the amount of the adjusting agent added is 2-3 kg / t, the amount of the collecting agent added is 0.5-2 kg / t, and the amount of the frother added is 0.1-0.3 kg / t.

5. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that: In step 3, the rough selected cerium oxyfluoride concentrate is added to a selected flotation tank, water is added to form a selected ore pulp, and then a regulator, a collector and a frother are sequentially added to the selected ore pulp for selection to obtain a selected cerium oxyfluoride concentrate and a selected monazite concentrate, comprising the following steps: Step 301: adding the rough cerium oxyfluoride concentrate to the first-stage concentrating flotation tank, and adding water to form a first concentrating pulp with a concentration of 25% to 32%; Step 302: adding a conditioning agent, a collecting agent and a frother to the first concentrated slurry in sequence for primary concentration to obtain a primary concentrated foam product and a primary concentrated tank bottom product, and returning the primary concentrated tank bottom product to the roughing tank as the concentrated monazite concentrate; Step 303: adding the primary concentration foam product to the second-stage concentration flotation tank, and adding water to form a second concentration pulp with a concentration of 25% to 32%; Step 304: adding a regulator, a collector and a frother to the second concentrated slurry in sequence for secondary concentration to obtain a secondary concentration foam product and a secondary concentration tank bottom product, and using the secondary concentration foam product as the separated cerium oxyfluoride concentrate; Step 305: Return the secondary concentration tank bottom product as the concentrated monazite concentrate to the first-stage concentration flotation tank.

6. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 5, characterized in that: In step 302 and step 304, the addition amount of the adjusting agent is 0.5-1.7 kg / t, the addition amount of the collecting agent is 0.15-1.2 kg / t, and the addition amount of the frother is 0.05-0.2 kg / t; the slurry temperature of the first concentrated slurry in step 301 and the second concentrated slurry in step 303 are both 20-35°C and the pH value is 3-5.

7. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that: In step 4, the roughing monazite concentrate and the concentrating monazite concentrate are added to a scavenging tank, water is added to form a scavenging pulp, and then a regulator, a collector and a frother are sequentially added to the scavenging pulp for scavenging, comprising the following steps: Step 401: adding the rougher monazite concentrate and the finer monazite concentrate to the first-stage scavenging tank, and adding water to prepare a first scavenging pulp with a concentration of 25% to 30%; Step 402: adding a conditioning agent, a collecting agent and a frother to the first scavenging pulp in sequence to perform a primary scavenging to obtain a primary scavenging foam product and a primary scavenging tank bottom product, and returning the primary scavenging foam product to the roughing tank; Step 403: adding the product from the bottom of the primary scavenging tank to the secondary scavenging tank, and adding water to form a second scavenging pulp with a concentration of 25% to 30%; Step 404: adding a conditioning agent, a collecting agent and a frother to the second scavenging pulp in sequence for secondary scavenging to obtain a secondary scavenging foam product and a secondary scavenging tank bottom product, and returning the secondary scavenging foam product to the first-stage scavenging tank, and using the secondary scavenging tank bottom product as the separated monazite concentrate.

8. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 7, characterized in that: In step 402 and step 404, the addition amount of the adjusting agent is 0.3~1 kg / t, the addition amount of the collecting agent is 0.25~1kg / t, and the addition amount of the frother is 0.05~0.2 kg / t; the slurry temperature of the first scavenging slurry in step 401 and the second scavenging slurry in step 403 are both 20~35℃, and the pH value is 3~5.

9. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that: The rare earth oxide REO grade in the mixed rare earth concentrate is 52%-67%.

10. The flotation separation method of bastnaesite and monazite in a mixed rare earth concentrate according to any one of claims 1 to 9, characterized in that: The adjusting agents in step 2 to step 4 are all alum or aluminum sulfate, the collecting agents are all phthalic acid, and the foaming agents are all No. 2 oil.

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