A method for flotation separation of bastnaesite and monazite in mixed rare earth concentrate

Abstract

The application discloses a flotation separation method of fluorcarbonate cerium and monazite in mixed rare earth concentrate. The fluorcarbonate cerium in the mixed rare earth concentrate is quickly phase-transformed into cerium oxyfluoride with better flotation performance through fluidized roasting of the mixed rare earth concentrate under inert gas. The phase-transformed product containing the cerium oxyfluoride is sequentially subjected to rough separation and fine separation in a rough separation flotation tank and a fine separation flotation tank to obtain rough separation monazite concentrate, fine separation monazite concentrate and separated cerium oxyfluoride concentrate. Finally, the rough separation monazite concentrate and the fine separation monazite concentrate are added into a scavenging tank for scavenging to obtain separated monazite concentrate, and the separation of the cerium oxyfluoride concentrate and the monazite concentrate in the phase-transformed product is completed. The separation method provided by the application can reduce the consumption of reagents used in the flotation process of the phase-transformed product and improve the separation efficiency of the phase-transformed product.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of rare earth beneficiation, and particularly relates to a flotation separation method of bastnaesite and monazite in mixed rare earth concentrate. BACKGROUND

[0002] The Bayan Obo rare earth reserves account for more than 80% of the total reserves in China, and belong to a large polymetallic deposit of iron-rare earth-niobium symbiosis (association), the main rare earth components of which are bastnaesite and monazite. The Bayan Obo rare earth minerals are relatively complex, the ore is finely disseminated, and the ore contains a large amount of fine-grained minerals. The traditional beneficiation process cannot realize the separation of the two. Therefore, the extraction of Bayan Obo rare earth elements must be based on mixed rare earth concentrate to develop a metallurgical process, and the concentrated sulfuric acid roasting method and the caustic soda heating decomposition process are commonly used. Because of the large difference in smelting performance between bastnaesite and monazite, the concentrated sulfuric acid roasting process produces a large amount of "three wastes" in the production process, increasing the difficulty and cost of treatment and recycling, and causing serious damage to the environment. The caustic soda heating decomposition method requires a high rare earth grade, and needs to be acid washed to remove calcium before alkali decomposition, increasing energy consumption. In comparison, the single bastnaesite or monazite concentrate metallurgical process has low energy consumption, simple process and strong adaptability. If the two kinds of rare earth minerals can be effectively separated from the source, the metallurgical process can be simplified, the energy consumption can be reduced, and the damage to the environment can be minimized.

[0003] Patent 201910060631.1 uses separation roughing, once roughing bastnaesite rough concentrate and once roughing monazite rough concentrate, and two times of flotation operation for each rough concentrate, to produce high-grade single bastnaesite concentrate and single monazite concentrate. However, the process flow is complex, and water washing is needed separately. For fine particles, it is difficult to use fine screening classification, and the process does not require the purity of the produced bastnaesite concentrate and monazite concentrate. Patent 202210388995.4 uses a roasting-flotation method to separate bastnaesite and monazite. The roasting temperature is 480-650℃, the roasting time is 0.5-2 hours, the flotation uses a one-roughing-three-concentrating-three-scavenging process, the added collector is phthalic acid or N-hydroxy phthalic imide, the added modifier is alum or aluminum sulfate, and the added frother is 2 # oil, to obtain single bastnaesite and monazite. However, the overall process is complex, the roasting time is long, the decomposition efficiency is low, and the consumption of flotation reagents is large.

[0004] In summary, how to provide a bastnaesite and monazite separation process with low energy consumption and high recovery rate, and to carry out intensive separation research on mixed rare earth concentrate, is a technical problem that needs to be solved by the technical personnel in the field. SUMMARY

[0005] In view of the above problems existing in the prior art, the application provides a flotation separation method of fluorcarbonate cerite and monazite in mixed rare earth concentrate.

[0006] To solve the above technical problems, the application adopts the following technical scheme:

[0007] The application provides a flotation separation method of fluorcarbonate cerite and monazite in mixed rare earth concentrate, comprising the following steps:

[0008] Step 1: fluidized roasting the mixed rare earth concentrate under inert gas, so that the fluorcarbonate cerite phase in the mixed rare earth concentrate is converted into cerium oxyfluoride, and a phase conversion product is obtained;

[0009] Step 2: adding the phase conversion product into a roughing flotation tank, adding water to prepare a roughing slurry, and then adding an adjusting agent, a collecting agent and a foaming agent into the roughing slurry in sequence to perform roughing, so that a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate are obtained;

[0010] Step 3: adding the roughing cerium oxyfluoride concentrate into a cleaning flotation tank, adding water to prepare a cleaning slurry, and then adding an adjusting agent, a collecting agent and a foaming agent into the cleaning slurry in sequence to perform cleaning, so that a cleaning cerium oxyfluoride concentrate and a cleaning monazite concentrate are obtained, and the cleaning cerium oxyfluoride concentrate is used as the separated cerium oxyfluoride concentrate;

[0011] Step 4: adding the roughing monazite concentrate and the cleaning monazite concentrate into a scavenging tank, adding water to prepare a scavenging slurry, and then adding an adjusting agent, a collecting agent and a foaming agent into the scavenging slurry in sequence to perform scavenging, so that a separated monazite concentrate is obtained.

[0012] Optionally, the fluidized roasting of the mixed rare earth concentrate under inert gas in step 1 makes the mixed rare earth concentrate undergo phase conversion, and a phase conversion product is obtained, comprising the following steps:

[0013] Step 101: continuously introducing inert gas into the bottom of a quartz tube containing the mixed rare earth concentrate, and using the inert gas as 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;

[0014] Step 102: placing the quartz tube into a roasting furnace, and fluidized roasting the mixed rare earth concentrate at a temperature of 550-750 DEG C for 15-45 min to complete the phase conversion of the fluorcarbonate cerite in the mixed rare earth concentrate;

[0015] Step 103: cooling the mixed rare earth concentrate after phase conversion under inert gas to 20-50 DEG C to obtain a phase conversion product.

[0016] Optionally, the mixed rare earth concentrate is fluidized roasting at a temperature of 700-750℃ for 15-20 min to complete the phase transformation of bastnaesite in the mixed rare earth concentrate.

[0017] Optionally, the pH value of the ore slurry in step 2 is 3-5, the addition amount of the adjusting agent is 2-3 kg / t, the addition amount of the collecting agent is 0.5-2 kg / t, and the addition amount of the frother is 0.1-0.3 kg / t.

[0018] Optionally, in step 3, the roughing cerium oxyfluoride concentrate is added into the cleaning flotation tank, water is added to prepare the cleaning ore slurry, and then the adjusting agent, the collecting agent and the frother are sequentially added into the cleaning ore slurry for cleaning to obtain the cleaning cerium oxyfluoride concentrate and the cleaning monazite concentrate, comprising the following steps:

[0019] Step 301: adding the roughing cerium oxyfluoride concentrate into the first-stage cleaning flotation tank, and adding water to prepare the first cleaning ore slurry with a concentration of 25%-32%;

[0020] Step 302: sequentially adding the adjusting agent, the collecting agent and the frother into the first cleaning ore slurry for primary cleaning to obtain the primary cleaning froth product and the primary cleaning tank bottom product, and returning the primary cleaning tank bottom product as the cleaning monazite concentrate to the roughing tank;

[0021] Step 303: adding the primary cleaning froth product into the second-stage cleaning flotation tank, and adding water to prepare the second cleaning ore slurry with a concentration of 25%-32%;

[0022] Step 304: sequentially adding the adjusting agent, the collecting agent and the frother into the second cleaning ore slurry for secondary cleaning to obtain the secondary cleaning froth product and the secondary cleaning tank bottom product, and returning the secondary cleaning froth product as the separated cerium oxyfluoride concentrate;

[0023] Step 305: returning the secondary cleaning tank bottom product as the cleaning monazite concentrate to the first-stage cleaning flotation tank.

[0024] Optionally, in steps 302 and 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; and the ore slurry temperature of the first cleaning ore slurry in step 301 and the second cleaning ore slurry in step 303 is 20-35℃, and the pH value is 3-5.

[0025] Optionally, in step 4, the roughing monazite concentrate and the cleaning monazite concentrate are added into the scavenging tank, water is added to prepare the scavenging ore slurry, and then the adjusting agent, the collecting agent and the frother are sequentially added into the scavenging ore slurry for scavenging, comprising the following steps:

[0026] Step 401: the rough monazite concentrate and the refined monazite concentrate are added into the first stage cleaning tank, and water is added to prepare a first cleaning slurry with a concentration of 25%-30%;

[0027] Step 402: the first cleaning slurry is sequentially added with an adjusting agent, a collecting agent and a foaming agent for primary cleaning, to obtain a primary cleaning foam product and a primary cleaning tank bottom product, and the primary cleaning foam product is returned to the roughing tank;

[0028] Step 403: the primary cleaning tank bottom product is added into the second stage cleaning tank, and water is added to prepare a second cleaning slurry with a concentration of 25%-30%;

[0029] Step 404: the second cleaning slurry is sequentially added with an adjusting agent, a collecting agent and a foaming agent for secondary cleaning, to obtain a secondary cleaning foam product and a secondary cleaning tank bottom product, and the secondary cleaning foam product is returned to the first stage cleaning tank, and the secondary cleaning tank bottom product is used as the separated monazite concentrate.

[0030] Optionally, the adding amount of the adjusting agent in steps 402 and 404 is 0.3-1 kg / t, the adding amount of the collecting agent is 0.25-1 kg / t, and the adding amount of the foaming agent is 0.05-0.2 kg / t; the slurry temperature of the first cleaning slurry in step 401 and the second cleaning slurry in step 403 is 20-35℃, and the pH value is 3-5.

[0031] Optionally, the rare earth oxide REO grade of the mixed rare earth concentrate is 52%-67%.

[0032] Optionally, the adjusting agent in steps 2-4 is alum or aluminum sulfate, the collecting agent is phthalic acid, and the foaming agent is No. 2 oil.

[0033] The application provides a flotation separation method of bastnaesite and monazite in mixed rare earth concentrate, which can quickly convert the bastnaesite in the mixed rare earth concentrate into cerium oxyfluoride with better flotation performance through fluidized roasting of the mixed rare earth concentrate under inert gas; the mineral phase conversion product containing the cerium oxyfluoride is sequentially subjected to roughing and cleaning in a roughing flotation tank and a cleaning flotation tank to obtain roughing monazite concentrate, cleaning monazite concentrate and separated cerium oxyfluoride concentrate; finally, the roughing monazite concentrate and the cleaning monazite concentrate are added into a scavenging tank for scavenging to obtain the separated monazite concentrate, and the separation of the cerium oxyfluoride concentrate and the monazite concentrate in the mineral phase conversion product is completed. The separation method provided by the application has a shorter roasting time of the mixed rare earth concentrate, and can improve the separation efficiency of the mineral phase conversion product while reducing the consumption of reagents used in the flotation process of the mineral phase conversion product, and finally obtain cerium oxyfluoride concentrate with a recovery rate greater than 92% and a purity greater than 97%, and monazite concentrate with a recovery rate and purity both greater than 90%, in addition, the cerium oxyfluoride concentrate separated by the method can be directly leached without re-roasting, and Baiyunebo rare earth elements extraction can use single cerium oxyfluoride or monazite as the raw material of the smelting process, thereby reducing environmental pollution and production cost.

[0034] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and the appended drawings.

[0035] The technical solutions of the present application will be further described in detail below with the help of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A flow chart of a flotation separation method of bastnaesite and monazite in mixed rare earth concentrate according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with the help of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0038] The flotation separation method of bastnaesite and monazite in mixed rare earth concentrate provided by the present application comprises the following steps:

[0039] Step 1: fluidized roasting of the mixed rare earth concentrate under inert gas to convert the bastnaesite phase in the mixed rare earth concentrate into cerium oxyfluoride, to obtain a phase conversion product;

[0040] Step 2: adding the phase conversion product into a roughing flotation tank, adding water to prepare a roughing slurry, and then sequentially adding a regulator, a collector and a frother into the roughing slurry to perform roughing, to obtain a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate;

[0041] Step 3: adding the roughing cerium oxyfluoride concentrate into a cleaning flotation tank, adding water to prepare a cleaning slurry, and then sequentially adding a regulator, a collector and a frother into the cleaning slurry to perform cleaning, to obtain a cleaning cerium oxyfluoride concentrate and a cleaning monazite concentrate, and the cleaning cerium oxyfluoride concentrate is taken as the separated cerium oxyfluoride concentrate;

[0042] Step 4: adding the roughing monazite concentrate and the cleaning monazite concentrate into a scavenging tank, adding water to prepare a scavenging slurry, and then sequentially adding a regulator, a collector and a frother into the scavenging slurry to perform scavenging, to obtain the separated monazite concentrate.

[0043] Here, the inert gas can 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.

[0044] In Step 1, by using the fluidized roasting method with obvious mass and heat transfer effect, the conversion rate of bastnaesite can be accelerated, and the obtained cerium oxyfluoride can be directly used for rare earth leaching without further roasting, so that Step 1 provided in the embodiment can open up a new way for further extraction of rare earth elements from single bastnaesite or mixed rare earth concentrate; at the same time, by fluidized roasting of the mixed rare earth concentrate under inert gas, the bastnaesite (REFCO3) in the mixed rare earth concentrate can be directionally converted into cerium oxyfluoride (REOF) which is easier to float, and since the monazite in the mixed rare earth concentrate is stable and does not change in phase in this step, the bastnaesite phase in the mixed rare earth concentrate can be converted into cerium oxyfluoride through Step 1, which can facilitate the subsequent flotation separation of cerium oxyfluoride and monazite in the phase conversion product, and further avoid the "three wastes" problem caused by concentrated sulfuric acid roasting and reduce environmental pollution.

[0045] In the formula, the fluidized roasting reaction of bastnaesite in the rare earth concentrate under inert gas is: REFCO3→REOF+CO2↑.

[0046] In step 2, after roughing the roughing slurry by the adjusting agent, the collector and the frother, a roughing froth product and a roughing tank bottom product can be obtained, wherein the roughing froth product is a first roughing cerium oxyfluoride concentrate, and the roughing tank bottom product is a first roughing monazite concentrate. Therefore, the flotation of the cerium oxyfluoride concentrate can be realized by roughing the roughing slurry by the adjusting agent, the collector and the frother, and then the first roughing separation of the cerium oxyfluoride concentrate and the monazite concentrate can be realized. Similarly, in step 3, after cleaning the cleaning slurry by the adjusting agent, the collector and the frother, a cleaning froth product and a cleaning tank bottom product can be obtained, wherein the cleaning froth product is a cleaning cerium oxyfluoride concentrate, and the cleaning tank bottom product is a cleaning monazite concentrate. Therefore, the flotation of the cerium oxyfluoride concentrate can be realized by cleaning the cleaning slurry by the adjusting agent, the collector and the frother, and then the cleaning separation of the cerium oxyfluoride concentrate and the monazite concentrate can be realized. Finally, after scavenging the scavenging slurry by the adjusting agent, the collector and the frother, a scavenging froth product and a scavenging tank bottom product can be obtained, wherein the scavenging froth product is a scavenging cerium oxyfluoride concentrate, and the scavenging tank bottom product is a scavenging monazite concentrate. Therefore, the flotation of the cerium oxyfluoride concentrate can be realized by scavenging the scavenging slurry by the adjusting agent, the collector and the frother, and then the scavenging separation of the cerium oxyfluoride concentrate and the monazite concentrate can be realized.

[0047] In the embodiment, by fluidizing roasting the mixed rare earth concentrate under the inert gas, the bastnaesite in the mixed rare earth concentrate can be quickly phase-transformed into cerium oxyfluoride with better flotation performance. Then, the phase-transformed product containing the cerium oxyfluoride is sequentially subjected to roughing and cleaning in the roughing flotation tank and the cleaning flotation tank to obtain the roughing monazite concentrate, the cleaning monazite concentrate and the separated cerium oxyfluoride concentrate. Finally, the roughing monazite concentrate and the cleaning monazite concentrate are added into the scavenging tank for scavenging to obtain the separated monazite concentrate, and the separation of the cerium oxyfluoride concentrate and the monazite concentrate in the phase-transformed product is completed. The separation method provided in the application not only has a shorter roasting time of the mixed rare earth concentrate, but also can improve the separation efficiency of the phase-transformed product while reducing the consumption of the reagents used in the flotation process of the phase-transformed product. In addition, the cerium oxyfluoride concentrate separated by the method can be directly leached without re-roasting, and the Baiyunebo rare earth elements extraction can use single cerium oxyfluoride or monazite as the raw material of the smelting process, thereby reducing environmental pollution and production cost.

[0048] In some possible embodiments, the fluidizing roasting of the mixed rare earth concentrate under the inert gas in step 1 to make the mixed rare earth concentrate phase-transformed to obtain the phase-transformed product includes the following steps:

[0049] Step 101: continuously introduce inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and use the inert gas as fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein the flow rate of the inert gas introduced into the quartz tube is 500 mL / min;

[0050] Step 102: place the quartz tube into a roasting furnace, and fluidize roast the mixed rare earth concentrate at a temperature of 550-750℃ for 15-45 min to complete the phase transformation of bastnaesite in the mixed rare earth concentrate;

[0051] Step 103: cool the phase-transformed mixed rare earth concentrate under inert gas to 20-50℃ to obtain a phase-transformed product.

[0052] 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, and then the quartz tube is placed into the roasting furnace.

[0053] In step 101, by continuously introducing inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and using the inert gas as fluidizing gas, the mixed rare earth concentrate can be kept in a fluidized state, and the air in the quartz tube can be discharged to prevent oxidation of bastnaesite and cerium oxyfluoride obtained by 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 bastnaesite and its phase-transformed product. In addition, in step 103, by cooling the phase-transformed mixed rare earth concentrate under inert gas, the problem of poor floatability of Ce(IV) caused by oxidation of bastnaesite and its phase-transformed product can be avoided.

[0054] In this embodiment, by selecting fluidized roasting with better mass and heat transfer effect, compared with the traditional roasting process, bastnaesite can be quickly decomposed without adding additives, and the phase transformation of bastnaesite is realized; at the same time, by using inert gas as fluidizing gas, and performing roasting and cooling of the mixed rare earth concentrate under inert gas, not only can bastnaesite be quickly and directionally converted into cerium oxyfluoride, but also the problem of poor floatability of Ce(IV) caused by oxidation of bastnaesite and its phase-transformed product can be avoided.

[0055] In some possible embodiments, the mixed rare earth concentrate is fluidized roasted at a temperature of 700-750℃ for 15-20 min to complete the phase transformation of bastnaesite in the mixed rare earth concentrate.

[0056] Here, when the mixed rare earth concentrate is fluidized roasting at a temperature of 700~750℃ for 15~20 min, the conversion rate of bastnaesite phase 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℃ and the roasting time is selected as 15~20 min. Of course, the respective range of the fluidized roasting temperature and the roasting time is determined by the inventors through a large number of experiments, and the performance is optimized while the cost is sufficiently reduced by controlling in the appropriate range.

[0057] In the present embodiment, the conversion of bastnaesite phase in the mixed rare earth concentrate is completed and the conversion rate of bastnaesite phase is improved by fluidizing roasting the mixed rare earth concentrate at a temperature of 700~750℃ for 15~20 min.

[0058] In some possible implementation examples, the pH value of the ore slurry in step 2 is 3~5, the adding amount of the adjusting agent is 2~3 kg / t, the adding amount of the collecting agent is 0.5~2 kg / t, and the adding amount of the frother is 0.1~0.3 kg / t.

[0059] Here, the pH value of the ore slurry in step 2 can be but is not limited to 3, 3.5, 4, 4.5 and 5; the adding amount of the adjusting agent 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 adding amount of the collecting agent 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; and the adding amount of the frother 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.

[0060] In some possible implementation examples, the rough selected cerium oxyfluoride concentrate is added into the cleaning flotation tank in step 3, water is added to prepare the cleaning ore slurry, and then the adjusting agent, the collecting agent and the frother are sequentially added into the cleaning ore slurry for cleaning to obtain the cleaning cerium oxyfluoride concentrate and the cleaning monazite concentrate, including the following steps.

[0061] Step 301: the rough selected cerium oxyfluoride concentrate is added into the first-stage cleaning flotation tank, and water is added to prepare the first-stage cleaning ore slurry with a concentration of 25%~32%;

[0062] Step 302: the adjusting agent, the collecting agent and the frother are sequentially added into the first-stage cleaning ore slurry for one-stage cleaning to obtain the one-stage cleaning froth product and the one-stage cleaning tank bottom product, and the one-stage cleaning tank bottom product is returned to the rough flotation tank as the cleaning monazite concentrate;

[0063] Step 303: adding the primary concentration froth product into the second-stage concentration flotation tank, and adding water to adjust the second-stage concentration slurry to a concentration of 25% to 32%;

[0064] Step 304: sequentially adding the conditioning agent, the collector and the frother into the second-stage concentration slurry to perform secondary concentration, to obtain a secondary concentration froth product and a secondary concentration tank bottom product, and to take the secondary concentration froth product as the separated cerium oxyfluoride concentrate;

[0065] Step 305: taking the secondary concentration tank bottom product as the concentration monazite concentrate and returning it to the first-stage concentration flotation tank.

[0066] It should be noted that in step 302: the primary concentration froth product is the primary concentration cerium oxyfluoride concentrate, and the primary concentration tank bottom product is the concentration monazite concentrate; in step 304: the secondary concentration froth product is the secondary concentration cerium oxyfluoride concentrate, and the secondary concentration tank bottom product is the concentration monazite concentrate; therefore, returning the primary concentration tank bottom product as the concentration monazite concentrate to the roughing tank can make the concentration monazite concentrate separated in the roughing flotation tank in the next time of flotation separation of the fluorine oxide cerium and monazite in the mixed rare earth concentrate phase transformation product; in step 305: because the secondary concentration tank bottom product is the concentration monazite concentrate, in order to separate the monazite concentrate from the cerium oxyfluoride concentrate, the secondary concentration tank bottom product is returned to the first-stage concentration flotation tank, so that the secondary concentration tank bottom product can be returned to the roughing tank with the primary concentration tank bottom product in the first-stage concentration flotation tank, and the secondary concentration tank bottom product can be added from the roughing tank to the scavenging tank to complete the scavenging of the secondary concentration tank bottom product in the scavenging tank.

[0067] In the embodiment, the roughing cerium oxyfluoride concentrate is added to the first-stage concentration flotation tank to complete the primary concentration of the roughing cerium oxyfluoride concentrate, and the obtained primary concentration tank bottom product is returned to the roughing tank as the concentration monazite concentrate; then, the obtained primary concentration froth product is added to the second-stage concentration flotation tank to complete the secondary concentration of the cerium oxyfluoride concentrate, and the secondary concentration froth product is taken as the concentration cerium oxyfluoride concentrate, and the obtained secondary concentration tank bottom product is returned to the first-stage concentration flotation tank, to realize the twice concentration of the roughing cerium oxyfluoride concentrate, to obtain the cerium oxyfluoride concentrate with high purity, and to make the primary concentration tank bottom product and the secondary concentration tank bottom product separated in the concentration process of the roughing cerium oxyfluoride concentrate returned to the roughing tank and the first-stage concentration flotation tank respectively, so that the primary concentration tank bottom product and the secondary concentration tank bottom product can be added to the scavenging tank to be scavenged and separated, to improve the recovery rate of monazite.

[0068] In some possible implementation embodiments, the amount of the adjusting agent added in steps 302 and 304 is 0.5-1.7 kg / t, the amount of the collector added is 0.15-1.2 kg / t, and the amount of the frother added is 0.05-0.2 kg / t; the pulp temperature of the first cleaning pulp in step 301 and the second cleaning pulp in step 303 is 20-35℃, and the pH value is 3-5.

[0069] Here, the amount of the adjusting agent added in steps 302 and 304 can be, but is not limited to, 0.5 kg / t, 0.8 kg / t, 1.1 kg / t, 1.4 kg / t, and 1.7 kg / t; the amount of the collector added in steps 302 and 304 can be, but is 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 steps 302 and 304 can be, but is not limited to, 0.05 kg / t, 0.1 kg / t, 0.15 kg / t, and 0.2 kg / t. The pulp temperature of the first cleaning pulp in step 301 and the second cleaning pulp in step 303 can be, but is not limited to, 20℃, 25℃, 30℃, and 35℃, and the pH value of the first cleaning pulp in step 301 and the second cleaning pulp in step 303 can be, but is not limited to, 3, 3.5, 4, 4.5, and 5.

[0070] In some possible implementation embodiments, in step 4, the rough monazite concentrate and the cleaning monazite concentrate are added to the cleaning tank, water is added to prepare the cleaning pulp, and then the adjusting agent, the collector, and the frother are sequentially added to the cleaning pulp for cleaning, including the following steps.

[0071] Step 401: The rough monazite concentrate and the cleaning monazite concentrate are added to the first-stage cleaning tank, and water is added to prepare the first cleaning pulp with a concentration of 25%-30%;

[0072] Step 402: The adjusting agent, the collector, and the frother are sequentially added to the first cleaning pulp for primary cleaning, to obtain the primary cleaning froth product and the primary cleaning tank bottom product, and the primary cleaning froth product is returned to the roughing tank;

[0073] Step 403: The primary cleaning tank bottom product is added to the second-stage cleaning tank, and water is added to prepare the second cleaning pulp with a concentration of 25%-30%;

[0074] Step 404: The adjusting agent, the collector, and the frother are sequentially added to the second cleaning pulp for secondary cleaning, to obtain the secondary cleaning froth product and the secondary cleaning tank bottom product, and the secondary cleaning froth product is returned to the first-stage cleaning tank, and the secondary cleaning tank bottom product is taken as the separated monazite concentrate.

[0075] It should be noted that in step 402: the once-scavenged foam product is a once-scavenged cerium oxyfluoride concentrate, and the once-scavenged tank bottom product is a once-scavenged monazite concentrate; in step 404: the twice-scavenged foam product is a twice-scavenged cerium oxyfluoride concentrate, and the twice-scavenged tank bottom product is a twice-scavenged monazite concentrate; therefore, returning the once-scavenged foam product to the roughing tank can make the once-scavenged foam product be separated out in the roughing flotation tank when the fluorine oxide cerium and monazite in the phase transformation product of the mixed rare earth concentrate are separated in the next time; in step 404: because the twice-scavenged foam product is a twice-scavenged cerium oxyfluoride concentrate, in order to separate the monazite concentrate from the cerium oxyfluoride concentrate, the twice-scavenged cerium oxyfluoride concentrate is returned to the first stage scavenging tank, so that the twice-scavenged cerium oxyfluoride concentrate can be returned to the roughing tank with the once-scavenged foam product in the first stage scavenging tank, and the twice-scavenged cerium oxyfluoride concentrate can be put into the cleaning flotation tank from the roughing tank to complete the cleaning of the twice-scavenged cerium oxyfluoride concentrate in the cleaning flotation tank.

[0076] In the embodiment, by adding the roughing monazite concentrate and the cleaning monazite concentrate into the first stage scavenging tank, the roughing monazite concentrate and the cleaning monazite concentrate are once-scavenged, and the once-scavenged foam product is returned to the roughing tank; then, the once-scavenged tank bottom product is added into the second stage scavenging tank to complete the twice-scavenging of the monazite, and the twice-scavenging tank bottom product is taken as the separated monazite concentrate, and the twice-scavenged foam product is returned to the first stage scavenging tank, so that the twice-scavenging of the roughing monazite concentrate and the cleaning monazite concentrate is realized, and the monazite concentrate with high purity is obtained, and the once-scavenged foam product and the twice-scavenged foam product separated in the scavenging process of the monazite concentrate are returned to the roughing tank and the first stage scavenging tank respectively, so that the once-scavenged foam product and the twice-scavenged foam product can be added into the cleaning flotation tank for cleaning separation, and the recovery rate of the cerium oxyfluoride is improved.

[0077] In some possible implementation examples, the addition amount of the adjusting agent in steps 402 and 404 is 0.3-1 kg / t, the addition amount of the collector is 0.25-1 kg / t, and the addition amount of the frother is 0.05-0.2 kg / t; the pulp temperature of the first scavenging pulp in step 401 and the pulp temperature of the second scavenging pulp in step 403 are both 20-35 ℃, and the pH value is both 3-5.

[0078] Herein, the adding amount of the regulator in step 402 and step 404 can be, but is not limited to, 0.3 kg / t, 0.5 kg / t, 0.8 kg / t, 1 kg / t; the adding amount of the collector in step 402 and step 404 can be, but is not limited to, 0.25 kg / t, 0.4 kg / t, 0.8 kg / t, 0.10 kg / t; the adding amount of the frother in step 402 and step 404 can be, but is not limited to, 0.05 kg / t, 0.1 kg / t, 0.15 kg / t, 0.2 kg / t. The pulp temperature of the first scavenging pulp in step 401 and the second scavenging pulp in step 403 can be, but is not limited to, 20℃, 25℃, 30℃ and 35℃, and the pH value of the first scavenging pulp in step 401 and the second scavenging pulp in step 403 can be, but is not limited to, 3, 3.5, 4, 4.5 and 5.

[0079] In some possible implementation examples, the rare earth oxide REO grade of the mixed rare earth concentrate is 52% to 67%.

[0080] Herein, the mixed rare earth concentrate can be a Baiyunebo mixed rare earth ore, the REO grade of the Baiyunebo mixed rare earth ore is 50% to 67%, and the rare earth ore mainly contains bastnaesite and monazite, wherein the F grade is 4% to 10%, and the fluorine-containing minerals are bastnaesite, fluorcarbonatocalcite and fluorite; the P grade is 4% to 10%, and the phosphorus-containing minerals are monazite and apatite.

[0081] In some possible implementation examples, the regulator in steps 2 to 4 is all alum or aluminum sulfate, the collector is all phthalic acid, and the frother is all No. 2 oil.

[0082] In the present embodiment, since the regulator, the collector and the frother used are all reagents with less environmental impact, the separation method used by the present application can avoid using reagents with large environmental impact, thereby reducing environmental pollution.

[0083] The following will describe a mixed rare earth concentrate flotation separation method provided by the present application through examples. It should be noted that, in the following examples, the methods, reagents and materials, unless otherwise specified, can be obtained from commercial channels; and the test methods, unless otherwise specified, are all conventional methods.

[0084] Example 1

[0085] The mixed rare earth concentrate flotation separation method provided by the present embodiment comprises the following steps:

[0086] Step 1: Nitrogen gas is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate with a rare earth oxide (REO) grade of 64.8%, and the nitrogen gas is used as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein, the flow rate of nitrogen gas introduced into the quartz tube is 500 mL / min.

[0087] Step 2: Place the quartz tube into the roasting furnace and fluidize and roast the mixed rare earth concentrate at 700℃ for 20 minutes to complete the phase transformation of fluorocarbon cerium ore in the mixed rare earth concentrate.

[0088] Step 3: Cool the mixed rare earth concentrate that has undergone mineral phase transformation to 35°C under nitrogen to obtain the mineral phase transformation product;

[0089] Step 4: Add the mineral phase transformation product to the roughing flotation cell, add water to prepare a roughing slurry with a concentration of 33% and a pH of 4.6, and then add 2.2 kg / t of alum, 1.2 kg / t of phthalic acid, and 2 kg / t of sodium phthalate to the roughing slurry at a temperature of 35℃. # The oil was roughed at 0.2 kg / t to obtain roughed cerium oxyfluoride concentrate and roughed monazite concentrate;

[0090] Step 5: Add the roughing cerium oxyfluoride concentrate to the first-stage cleaning flotation cell, and add water to prepare a first-stage cleaning slurry with a concentration of 29% and a pH of 4.5;

[0091] Step 6: Add 1.2 kg / t of alum, 0.3 kg / t of phthalic acid, and 2 kg / t of sodium hydroxide to the first refined ore pulp at a temperature of 35℃. # The oil is treated at a rate of 0.15 kg / t to obtain a primary fine-refined foam product and a primary fine-refined bottom product. The primary fine-refined bottom product is then returned to the roughing cell as fine monazite concentrate.

[0092] Step 7: Add the primary selected froth product to the secondary selected flotation cell, and add water to prepare a secondary selected slurry with a concentration of 27% and a pH value of 4.5;

[0093] Step 8: Add 0.6 kg / t of alum, 0.2 kg / t of phthalic acid, and 2 kg / t of sodium hydroxide to the second concentrate at a temperature of 35℃. # 0.1 kg / t of oil is subjected to secondary beneficiation to obtain secondary beneficiation foam product and secondary beneficiation tank bottom product. The secondary beneficiation foam product is used as the separated beneficiation cerium oxyfluoride concentrate.

[0094] Step 9: Return the product from the bottom of the secondary cleaning cell to the primary cleaning flotation cell as refined monazite concentrate;

[0095] Step 10: the rough monazite concentrate and the refined monazite concentrate are added into the first stage scavenging tank, and water is added to prepare a first scavenging slurry with a concentration of 27% and a pH value of 4;

[0096] Step 11: the first scavenging slurry at a temperature of 35℃ is sequentially added with alum 0.7 kg / t, phthalic acid 0.8 kg / t and 2 # oil 0.15 kg / t for primary scavenging to obtain a primary scavenging froth product and a primary scavenging tank bottom product, and the primary scavenging froth product is returned to the roughing tank;

[0097] Step 12: the primary scavenging tank bottom product is added into the second stage scavenging tank, and water is added to prepare a second scavenging slurry with a concentration of 27% and a pH value of 4;

[0098] Step 13: the second scavenging slurry at a temperature of 35℃ is sequentially added with alum 0.4 kg / t, phthalic acid 0.6 kg / t and 2 # oil 0.15 kg / t for secondary scavenging to obtain a secondary scavenging froth product and a secondary scavenging tank bottom product, and the secondary scavenging froth product is returned to the first stage scavenging tank, and the secondary scavenging tank bottom product is used as the separated monazite concentrate.

[0099] The purity of the refined cerium oxyfluoride concentrate separated in this embodiment 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%.

[0100] Example 2

[0101] The flotation separation method for fluorcarbonate and monazite in the mixed rare earth concentrate provided in this embodiment includes the following steps:

[0102] Step 1: nitrogen gas is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate with a rare earth oxide REO grade of 53.55%, and the nitrogen gas is used as 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 gas introduced into the quartz tube is 500 mL / min;

[0103] Step 2: the quartz tube is placed in a calcination furnace, and the mixed rare earth concentrate is fluidized calcined at a temperature of 550℃ for 45 min to complete the phase transformation of the fluorcarbonate in the mixed rare earth concentrate;

[0104] Step 3: the phase-transformed mixed rare earth concentrate is cooled to 25℃ under nitrogen gas to obtain a phase-transformed product;

[0105] Step 4: The mineralogical transformation product is added into the roughing flotation cell, and water is added to prepare a roughing slurry with a concentration of 35% and a pH value of 4; then, 3 kg / t of aluminum sulfate, 2 kg / t of phthalic acid, and 0.3 kg / t of 2 # oil are sequentially added into the roughing slurry with a temperature of 30°C to perform roughing, so as to obtain a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate;

[0106] Step 5: The roughing cerium oxyfluoride concentrate is added into the first-stage cleaning flotation cell, and water is added to prepare a first-stage cleaning slurry with a concentration of 32% and a pH value of 3.5;

[0107] Step 6: 1 kg / t of aluminum sulfate, 0.8 kg / t of phthalic acid, and 0.2 kg / t of 2 # oil are sequentially added into the first-stage cleaning slurry with a temperature of 30°C to perform first-stage cleaning, so as to obtain a first-stage cleaning froth product and a first-stage cleaning cell bottom product, and the first-stage cleaning cell bottom product is returned to the roughing cell as the cleaning monazite concentrate;

[0108] Step 7: The first-stage cleaning froth product is added into the second-stage cleaning flotation cell, and water is added to prepare a second-stage cleaning slurry with a concentration of 28% and a pH value of 3.5;

[0109] Step 8: 0.7 kg / t of aluminum sulfate, 0.3 kg / t of phthalic acid, and 0.1 kg / t of 2 # oil are sequentially added into the second-stage cleaning slurry with a temperature of 30°C to perform second-stage cleaning, so as to obtain a second-stage cleaning froth product and a second-stage cleaning cell bottom product, and the second-stage cleaning froth product is returned to the cleaning cerium oxyfluoride concentrate after separation;

[0110] Step 9: The second-stage cleaning cell bottom product is returned to the first-stage cleaning flotation cell as the cleaning monazite concentrate;

[0111] Step 10: The roughing monazite concentrate and the cleaning monazite concentrate are added into the first-stage scavenging cell, and water is added to prepare a first-stage scavenging slurry with a concentration of 29% and a pH value of 3.2;

[0112] Step 11: 1 kg / t of aluminum sulfate, 1 kg / t of phthalic acid, and 0.15 kg / t of 2 # oil are sequentially added into the first-stage scavenging slurry with a temperature of 30°C to perform first-stage scavenging, so as to obtain a first-stage scavenging froth product and a first-stage scavenging cell bottom product, and the first-stage scavenging froth product is returned to the roughing cell;

[0113] Step 12: The first-stage scavenging cell bottom product is added into the second-stage scavenging cell, and water is added to prepare a second-stage scavenging slurry with a concentration of 29% and a pH value of 3.2;

[0114] Step 13: Add 0.5 kg / t aluminum sulfate, 0.8 kg / t phthalic acid, and 2 kg / t aluminum sulfate sequentially to the second scavenging slurry at a temperature of 30℃. # The oil is subjected to secondary scavenging at a rate of 0.15 kg / t to obtain secondary scavenging foam product and secondary scavenging tank bottom product. 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.

[0115] The purity of the selected cerium oxyfluoride concentrate separated in this embodiment 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%.

[0116] Example 3

[0117] This embodiment provides a flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, comprising the following steps:

[0118] Step 1: Nitrogen gas is continuously introduced into the bottom of a quartz tube containing a mixed rare earth concentrate with a rare earth oxide (REO) grade of 60.42%, and the nitrogen gas is used as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein, the flow rate of nitrogen gas introduced into the quartz tube is 500 mL / min.

[0119] Step 2: Place the quartz tube into the roasting furnace and fluidize and roast the mixed rare earth concentrate at 650℃ for 30 minutes to complete the phase transformation of fluorocarbon cerium ore in the mixed rare earth concentrate.

[0120] Step 3: Cool the mixed rare earth concentrate that has undergone mineral phase transformation to 30°C under nitrogen to obtain the mineral phase transformation product;

[0121] Step 4: Add the mineral phase transformation product to the roughing flotation cell, add water to adjust it into a roughing slurry with a concentration of 28% and a pH of 4.6, and then add 2.5 kg / t aluminum sulfate, 1.4 kg / t phthalic acid, and 2% aluminum sulfate to the roughing slurry at a temperature of 20℃ in sequence. # The oil was roughed at a rate of 0.25 kg / t to obtain roughed cerium oxyfluoride concentrate and roughed monazite concentrate.

[0122] Step 5: Add the roughing cerium oxyfluoride concentrate to the first-stage cleaning flotation cell, and add water to prepare a first-stage cleaning slurry with a concentration of 28% and a pH of 4;

[0123] Step 6: Add 1.3 kg / t aluminum sulfate, 0.5 kg / t phthalic acid, and 2 kg / t aluminum sulfate sequentially to the first refined ore pulp at a temperature of 20℃. # 0.2 kg / t of oil is subjected to a first-stage fine cleaning process to obtain a first-stage fine cleaning foam product and a first-stage fine cleaning bottom product. The first-stage fine cleaning bottom product is then returned to the roughing cell as fine monazite concentrate.

[0124] Step 7: add the primary cleaning froth product into the second-stage cleaning flotation tank, and add water to prepare a second cleaning slurry with a concentration of 25% and a pH value of 4;

[0125] Step 8: add aluminum sulfate 0.9 kg / t, phthalic acid 0.25 kg / t and 2# oil 0.13 kg / t into the second cleaning slurry with a temperature of 20℃ in sequence to perform secondary cleaning, to obtain a secondary cleaning froth product and a secondary cleaning tank bottom product, and the secondary cleaning froth product is taken as the separated cleaning cerium oxyfluoride concentrate; #

[0126] Step 9: take the secondary cleaning tank bottom product as the cleaning monazite concentrate, and return it to the first-stage cleaning flotation tank;

[0127] Step 10: add the rough monazite concentrate and the cleaning monazite concentrate into the first-stage scavenging tank, and add water to prepare a first scavenging slurry with a concentration of 29% and a pH value of 3.8;

[0128] Step 11: add alum 0.9 kg / t, phthalic acid 0.8 kg / t and 2# oil 0.2 kg / t into the first scavenging slurry with a temperature of 30℃ in sequence to perform primary scavenging, to obtain a primary scavenging froth product and a primary scavenging tank bottom product, and the primary scavenging froth product is returned to the rough flotation tank; #

[0129] Step 12: add the primary scavenging tank bottom product into the second-stage scavenging tank, and add water to prepare a second scavenging slurry with a concentration of 29% and a pH value of 2.8;

[0130] Step 13: add alum 0.6 kg / t, phthalic acid 0.4 kg / t and 2# oil 0.15 kg / t into the second scavenging slurry with a temperature of 20℃ in sequence to perform secondary scavenging, to obtain a secondary scavenging froth product and a secondary scavenging tank bottom product, and the secondary scavenging froth product is returned to the first-stage scavenging tank, and the secondary scavenging tank bottom product is taken as the separated monazite concentrate. #

[0131] The purity of the cleaning cerium oxyfluoride concentrate separated in the embodiment 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%.

[0132] Embodiment 4

[0133] The embodiment provides a flotation separation method for fluorocarbon cerite and monazite in a mixed rare earth concentrate, and the method comprises the following steps:

[0134] ​​​Step 1: continuously introduce nitrogen into the bottom of a quartz tube containing a mixed rare earth concentrate with a rare earth oxide REO grade of 66.73%, and use the nitrogen as 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;

[0135] Step 2: place the quartz tube into a calcination furnace, and fluidize calcine the mixed rare earth concentrate at a temperature of 750℃ for 15 min to complete the phase conversion of bastnaesite in the mixed rare earth concentrate;

[0136] Step 3: cool the phase-converted mixed rare earth concentrate to 40℃ under nitrogen to obtain a phase-converted product;

[0137] Step 4: add the phase-converted product into a roughing flotation tank, and add water to prepare a roughing slurry with a concentration of 30% and a pH value of 5; then sequentially add 2 kg / t of alum, 0.8 kg / t of phthalic acid, and 2 # oil 0.1 kg / t into the roughing slurry at a temperature of 25℃ to perform roughing, to obtain a roughing cerium oxyfluoride concentrate and a roughing monazite concentrate;

[0138] Step 5: add the roughing cerium oxyfluoride concentrate into a first-stage cleaning flotation tank, and add water to prepare a first cleaning slurry with a concentration of 29% and a pH value of 4.6;

[0139] Step 6: sequentially add 1 kg / t of alum, 0.2 kg / t of phthalic acid, and 2 # oil 0.15 kg / t into the first cleaning slurry at a temperature of 25℃ to perform primary cleaning, to obtain a primary cleaning froth product and a primary cleaning tank bottom product, and return the primary cleaning tank bottom product as a cleaning monazite concentrate to the roughing tank;

[0140] Step 7: add the primary cleaning froth product into a second-stage cleaning flotation tank, and add water to prepare a second cleaning slurry with a concentration of 28% and a pH value of 4.6;

[0141] Step 8: sequentially add 0.5 kg / t of alum, 0.15 kg / t of phthalic acid, and 2 # oil 0.05 kg / t into the second cleaning slurry at a temperature of 25℃ to perform secondary cleaning, to obtain a secondary cleaning froth product and a secondary cleaning tank bottom product, and return the secondary cleaning froth product as a separated cleaning cerium oxyfluoride concentrate;

[0142] Step 9: return the secondary cleaning tank bottom product as a cleaning monazite concentrate to the first-stage cleaning flotation tank;

[0143] Step 10: The rough monazite concentrate and the refined monazite concentrate are added to the first stage scavenging tank, and water is added to prepare a first scavenging slurry with a concentration of 29% and a pH value of 4.5;

[0144] Step 11: The first scavenging slurry at a temperature of 30℃ is sequentially added with alum 0.5 kg / t, phthalic acid 0.4 kg / t and 2 # oil 0.1 kg / t for primary scavenging to obtain a primary scavenging froth product and a primary scavenging tank bottom product, and the primary scavenging froth product is returned to the roughing tank;

[0145] Step 12: The primary scavenging tank bottom product is added to the second stage scavenging tank, and water is added to prepare a second scavenging slurry with a concentration of 27% and a pH value of 4.5;

[0146] Step 13: The second scavenging slurry at a temperature of 25℃ is sequentially added with alum 0.3 kg / t, phthalic acid 0.25 kg / t and 2 # oil 0.05 kg / t for secondary scavenging to obtain a secondary scavenging froth product and a secondary scavenging tank bottom product, and the secondary scavenging froth product is returned to the first stage scavenging tank, and the secondary scavenging tank bottom product is used as the separated monazite concentrate.

[0147] The purity of the refined cerium oxyfluoride concentrate separated in this embodiment 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%.

[0148] Comparative Example 1

[0149] Compared with Example 1, the flotation separation method of fluorcarbonate and monazite in the mixed rare earth concentrate provided in this embodiment is basically the same as the preparation method provided in Example 1, and the difference lies in that the mixed rare earth concentrate is not subjected to steps 2 and 3, that is, the fluorcarbonate is not subjected to the mineral phase conversion process, and the mixed rare earth concentrate is not subjected to the inert cooling process, but the mixed rare earth concentrate in step 1 is directly added to the roughing flotation tank for roughing separation, and other steps and process parameters involved remain unchanged.

[0150] The purity of the refined cerium oxyfluoride 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%.

[0151] Comparative Example 2

[0152] Compared with the embodiment 1, the flotation separation method of the bastnaesite and monazite in the mixed rare earth concentrate provided by the embodiment 2 is basically the same as the preparation method provided by the embodiment 1, and the difference lies in that the nitrogen involved in the step 1 and the step 2 is replaced by air, that is, the fluidized roasting of the mixed rare earth concentrate is carried out by using air as the fluidizing gas, and other steps and the process parameters involved are kept unchanged.

[0153] The purity of the separated bastnaesite concentrate 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%.

[0154] Comparative example 3

[0155] Compared with the embodiment 1, the flotation separation method of the bastnaesite and monazite in the mixed rare earth concentrate provided by the embodiment 2 is basically the same as the preparation method provided by the embodiment 1, and the difference lies in that the nitrogen involved in the step 1 and the step 2 is replaced by air, that is, the fluidized roasting of the mixed rare earth concentrate is carried out by using air as the fluidizing gas, and other steps and the process parameters involved are kept unchanged.

[0156] The purity of the separated bastnaesite concentrate 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%.

[0157] From the results of the above embodiment and the comparative examples, it can be seen that the flotation separation method adopted by the present application can well separate the bastnaesite and the monazite in the mixed rare earth concentrate, and the separated bastnaesite does not need to be roasted again, and can be directly leached, which opens up a new way for the extraction of rare earth elements in the mixed rare earth concentrate.

[0158] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate, characterized in that, Includes the following steps: Step 1: The mixed rare earth concentrate is subjected to fluidized roasting under inert gas to convert the bastnaesite mineral phase in the mixed rare earth concentrate into cerium oxyfluoride, thereby obtaining the mineral phase conversion product. Step 2: Add the mineral phase transformation product to the roughing flotation cell, add water to prepare a roughing slurry, and then add a modifier, collector and frother to the roughing slurry in sequence for roughing to obtain roughing cerium oxyfluoride concentrate and roughing monazite concentrate. Step 3: Add the rough cerium oxyfluoride concentrate to the fine flotation cell, add water to prepare fine slurry, and then add modifier, collector and frother to the fine slurry in sequence for fine treatment to obtain fine cerium oxyfluoride concentrate and fine monazite concentrate. The fine cerium oxyfluoride concentrate is used as the separated cerium oxyfluoride concentrate. Step 4: Add the rough monazite concentrate and the refined monazite concentrate to the scavenging tank, add water to prepare a scavenging slurry, and then add a modifier, a collector and a frother to the scavenging slurry in sequence for scavenging to obtain the separated monazite concentrate. Step 1, which involves fluidized bed roasting of the mixed rare earth concentrate under an inert gas atmosphere to induce a mineral phase transformation and obtain a mineral phase transformation product, includes the following steps: Step 101: Continuously introduce inert gas into the bottom of the quartz tube containing the mixed rare earth concentrate, and use the inert gas as a fluidizing gas to keep the mixed rare earth concentrate in the quartz tube in a fluidized state; wherein, the flow rate of the inert gas introduced into the quartz tube is 500 mL / min. Step 102: Place the quartz tube into a roasting furnace and fluidize and roast the mixed rare earth concentrate at a temperature of 550~750℃ for 15~45 min to complete the phase transformation of fluorocarbon cerium ore in the mixed rare earth concentrate. Step 103: Cool the mixed rare earth concentrate that has undergone mineral phase transformation to 20~50℃ under inert gas to obtain the mineral phase transformation product; The mixed rare earth concentrate is fluidized and roasted at 700~750℃ for 15~20 min to complete the phase transformation of bastnaesite in the mixed rare earth concentrate. In step 2, the pH value of the slurry is 3-5, the amount of the adjuster added is 2-3 kg / t, the amount of the collector added is 0.5-2 kg / t, and the amount of the frother added is 0.1-0.3 kg / t.

2. The flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate according to claim 1, characterized in that, Step 3, which involves adding the roughed cerium oxyfluoride concentrate to the refining flotation cell, adding water to prepare a refining slurry, and then sequentially adding a modifier, a collector, and a frother to the refining slurry for further refining to obtain refined cerium oxyfluoride concentrate and refined monazite concentrate, includes the following steps: Step 301: Add the roughed cerium oxyfluoride concentrate to the first-stage cleaning flotation cell, and add water to prepare a first-stage cleaning slurry with a concentration of 25%~32%; Step 302: Add modifier, collector and frother to the first refined slurry in sequence to perform a first-stage refining process to obtain a first-stage refined foam product and a first-stage refined bottom product. The first-stage refined bottom product is then returned to the roughing cell as the refined monazite concentrate. Step 303: Add the primary selected froth product to the second-stage selected flotation cell, and add water to prepare a second selected slurry with a concentration of 25%~32%; Step 304: Add modifier, collector and frother to the second refined slurry in sequence for secondary refining to obtain secondary refined foam product and secondary refined bottom product, and use the secondary refined foam product as the separated cerium oxyfluoride concentrate; Step 305: The product from the bottom of the secondary cleaning cell is returned to the first-stage cleaning flotation cell as the selected monazite concentrate.

3. The flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate according to claim 2, characterized in that, In steps 302 and 304, the amount of modifier added is 0.5~1.7 kg / t, the amount of collector added is 0.15~1.2 kg / t, and the amount of frother added is 0.05~0.2 kg / t; in step 301, the temperature of the first refined ore slurry and the pH value of the second refined ore slurry are 20~35℃ and 3~5 respectively.

4. The flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate according to claim 2, characterized in that, Step 4, which involves adding the rougher monazite concentrate and the refined monazite concentrate to a scavenging tank, adding water to prepare a scavenging slurry, and then sequentially adding a modifier, a collector, and a frother to the scavenging slurry for scavenging, includes the following steps: Step 401: Add the rough monazite concentrate and the refined monazite concentrate to the first-stage scavenging tank, and add water to prepare a first scavenging slurry with a concentration of 25%~30%; Step 402: Add modifier, collector and frother to the first scavenging slurry in sequence to perform a first scavenging to obtain a first scavenging foam product and a first scavenging tank bottom product, and return the first scavenging foam product to the roughing tank; Step 403: Add the product from the bottom of the primary scavenging tank to the secondary scavenging tank, and add water to prepare a secondary scavenging slurry with a concentration of 25%~30%; Step 404: Add modifier, collector and frother to the second scavenging slurry in sequence for secondary scavenging to obtain secondary scavenging foam product and secondary scavenging tank bottom product. Return the secondary scavenging foam product to the first-stage scavenging tank and use the secondary scavenging tank bottom product as the separated monazite concentrate.

5. The flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate according to claim 4, characterized in that, In steps 402 and 404, the amount of modifier added is 0.3~1 kg / t, the amount of collector added is 0.25~1 kg / t, and the amount of frother added is 0.05~0.2 kg / t; in step 401, the temperature of the first scavenging slurry and in step 403, the temperature of the second scavenging slurry is 20~35℃, and the pH value is 3~5.

6. The flotation separation method for 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%.

7. The flotation separation method for bastnaesite and monazite in a mixed rare earth concentrate according to any one of claims 1 to 6, characterized in that, The modifiers in steps 2 to 4 are all alum or aluminum sulfate, the collectors are all phthalic acid, and the foaming agents are all No. 2 oil.

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