Device and method for preparing fluoride from fluidized rare earth oxide

Abstract

The device comprises a quantitative feeding device, a preheating device, a fluorination reaction device and a cooling tank, the fluorination reaction device comprises a fluorination reactor and a cinder valve b, the input end of the fluorination reaction device is connected with the output end of the preheating device, and the output end of the preheating device is connected with the cooling tank. The interior of the fluorination reactor is in scattered fluidization / bubbling fluidization, the fluorination reactor is used for reaction of rare earth oxide and hydrogen fluoride gas, and the cinder valve b is located between the fluorination reaction device and the cooling tank; the input end of the cooling tank is connected with the output end of the fluorination reaction device, and the cooling tank is used for cooling high-temperature fluoride.According to the device and method for preparing the fluoride through the fluidized rare earth oxide, on one hand, cyclic utilization of hydrogen fluoride gas is achieved, cost is saved, on the other hand, continuous and stable preparation of the fluoride through the rare earth oxide can be achieved, and production efficiency is improved. And the yield and quality of fluoride are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of dry fluorination of rare earth oxides, and in particular to a device and method for preparing fluoride from fluidized rare earth oxides. Background Art

[0002] In recent years, with the increasing demand and quality requirements for rare earth fluorides in the traditional rare earth metallurgy field and the new materials and new technology fields, it is necessary to innovate on the basis of the original rare earth fluoride preparation process. As a dry fluorination process, the hydrogen fluoride gas method has the advantages of high product quality, short process flow, simple operation, high direct yield, and less impurities introduced in the process. It has potential advantages in the preparation of rare earth fluorides.

[0003] The main equipment for the dry rare earth oxide fluorination reaction in industry is a horizontal fluorination furnace. The rare earth oxide is in a static state, and the HF gas diffuses into the oxide powder layer. However, due to the existence of dead corners in the furnace, the materials in the furnace react unevenly; at the same time, the production is in intermittent operation, and the fluorination reactor needs to be heated up at the beginning of the reaction and cooled down after the reaction. The production efficiency is extremely low, which not only wastes energy but also takes up production time. Therefore, in order to achieve continuous and stable production of fluorides from rare earth oxides and ensure the output and quality of oxides, a research institution has proposed a process for producing fluorides from fluidized rare earth oxides.

[0004] Baotou Ruida Rare Earth Materials Co., Ltd. conducted a fluorination experiment of Nd2O3 in a single-tube fluidized bed, eliminating the influence of gas diffusion mass transfer, increasing the reaction rate between Nd2O3 and HF, and effectively shortening the production time. However, it is still an intermittent operation and cannot achieve industrial continuous production. Therefore, the fluidized rare earth oxide fluoride preparation process that can be continuously produced proposed in the present invention provides a practical solution for the preparation of fluorides from rare earth oxides, which has very important economic value. Summary of the invention

[0005] The invention discloses a device and method for preparing fluoride from fluidized rare earth oxide, aiming to solve the influence of gas diffusion and mass transfer in industrial dry fluorination experiment, improve the reaction rate between rare earth oxide and HF, realize industrial continuous production of fluoride, ensure the output and quality of rare earth oxide and other technical problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for preparing fluoride by fluidizing rare earth oxide, comprising:

[0008] A quantitative feeding device, the quantitative feeding device comprising a hopper, a loss-in-weight scale, and a rotary air lock machine, the loss-in-weight scale being arranged on the outer wall of the bottom end of the hopper, and the rotary air lock machine being arranged on the inner wall of the bottom end of the hopper;

[0009] A preheating device, the preheating device comprises a preheating tank and an ash discharge valve a, the input end of the preheating device is connected to the bottom end of the quantitative feeding device, and the rotary air lock is located between the preheating device and the quantitative feeding device, and the ash discharge valve a is located between the preheating tank and the fluorination reaction device;

[0010] A fluorination reaction device, comprising a fluorination reactor and an ash discharge valve b, wherein the input end of the fluorination reaction device is connected to the output end of the ash discharge valve a provided on the preheating device, and the ash discharge valve b is provided between the fluorination reactor and the cooling tank, the fluorination reactor is in a dispersed fluidization / bubbling fluidization state, and is provided with a hood and an air distribution plate, the fluorination reactor is used for the reaction of rare earth oxides and hydrogen gas, and the ash discharge valve b is located between the fluorination reactor and the cooling tank;

[0011] A cooling tank, the input end of which is connected to the output end of the fluorination reaction device, and is used to cool the high-temperature fluoride;

[0012] An exhaust gas treatment system, wherein the exhaust gas treatment system is connected to the fluorination reaction device, and the exhaust gas treatment system comprises a GGH flue gas heat exchanger, a condenser, a bag dust collector and an induced draft fan, and the GGH flue gas heat exchanger, the condenser, the bag dust collector and the induced draft fan are connected in sequence;

[0013] A gas distribution system, the gas distribution system comprising a buffer tank, a vent valve, a pressure reducing valve and a blower, and the vent valve, the pressure reducing valve and the blower are connected to the buffer tank at the same time, the gas distribution system is used to provide hydrogen fluoride to the fluorination reactor and provide a circulation path for hydrogen fluoride during the fluorination reaction;

[0014] An HF heater, the HF heater is connected to the fluorination reaction device and the buffer tank respectively, and is used to heat hydrogen fluoride;

[0015] A method for preparing fluoride by fluidizing rare earth oxides comprises the following specific steps:

[0016] S1: Rare earth oxides enter the preheating tank and fluorination reactor from the hopper;

[0017] S2: The rare earth oxide is heated in a preheating tank and hydrogen fluoride gas is introduced into a fluorination reactor. The oxide is subjected to dispersed fluidization / bubbling fluidization under the action of hydrogen fluoride gas. The hydrogen fluoride gas fully contacts the oxide and undergoes a fluorination reaction to generate fluoride and water vapor.

[0018] S3: After the fluorination reaction time is met, the ash discharge valve b at the bottom of the fluorination reactor is unloaded into the cooling tank, and the ash discharge valve a at the bottom of the preheating device is opened at the same time, and the preheated high-temperature rare earth oxide enters the fluorination reactor. The frequency of the ash discharge valve a and the ash discharge valve b is adjusted to achieve a stable material amount;

[0019] S4: The high-temperature fluoride produced during the fluorination reaction enters a cooling tank for cooling to obtain a finished fluoride;

[0020] S5: The residual hydrogen fluoride and water vapor in the fluorination reactor enter the tail gas treatment system, and are cooled by the GGH flue gas heat exchanger and condenser in turn, and most of the water vapor condenses and flows out;

[0021] S6: The flue gas generated after being treated by the exhaust gas treatment system enters the bag filter for filtration;

[0022] S7: The filtered flue gas is sent into the buffer tank through the induced draft fan;

[0023] S8: The flue gas in the buffer tank is then sent back into the fluorination reactor through the gas distribution system and the HF heater to participate in the reaction.

[0024] After being preheated by the preheating device, the rare earth oxide enters the fluorination reactor, and produces rare earth fluoride and water vapor with hydrogen fluoride gas under dispersed fluidization / bubbling fluidization. The high-temperature rare earth fluoride is cooled in the cooling tube by a water-cooling jacket to obtain a finished rare earth fluoride, and the residual hydrogen fluoride and water vapor in the fluorination reactor enter the exhaust gas treatment system. Since the concentration of hydrogen fluoride in the flue gas is relatively high, in order to save costs and make full use of resources, the flue gas is sent to the buffer tank through the induced draft fan, and at the same time, it is sent back to the fluorination reactor through the gas distribution system and the HF heater to participate in the reaction, so as to realize the recycling of HF gas. Under this structure, on the one hand, the recycling of hydrogen fluoride gas is realized to save costs, and on the other hand, the rare earth oxide can be used to continuously and stably prepare rare earth fluoride to ensure output and quality.

[0025] As can be seen from the above, a device for preparing fluoride from fluidized rare earth oxides includes: a quantitative feeding device, the quantitative feeding device includes a hopper, a weight loss scale, and a rotary air lock, the weight loss scale is arranged on the outer wall of the bottom end of the hopper, and the rotary air lock is arranged on the inner wall of the bottom end of the hopper; a preheating device, the preheating device includes a preheating tank and an ash discharge valve a, the input end of the preheating device is connected to the bottom end of the quantitative feeding device, and the rotary air lock is located between the preheating device and the quantitative feeding device, and the ash discharge valve a is located between the preheating tank and the fluorination reaction device; a fluorination reaction device, the fluorination reaction device includes a fluorination reactor and an ash discharge valve b, the input end of the fluorination reaction device is connected to the output end of the ash discharge valve a arranged on the preheating device, and the ash discharge valve b is arranged between the fluorination reactor and the cooling tank, the fluorination reactor is in a dispersed fluidization / bubbling fluidization, and is provided with a hood and an air distribution plate, and the fluorination The reactor is used for the reaction of rare earth oxides and hydrogen gas, and the ash discharge valve b is located between the fluorination reactor and the cooling tank; the cooling tank, the input end of the cooling tank is connected to the output end of the fluorination reaction device, and is used to cool the high-temperature fluoride; the tail gas treatment system, the tail gas treatment system is connected to the fluorination reaction device, the tail gas treatment system includes a GGH flue gas heat exchanger, a condenser, a bag dust collector and an induced draft fan, and the GGH flue gas heat exchanger, the condenser, the bag dust collector and the induced draft fan are connected in sequence; the gas distribution system, the gas distribution system includes a buffer tank, a vent valve, a pressure reducing valve and a blower, and the vent valve, the pressure reducing valve and the blower are connected to the buffer tank at the same time, the gas distribution system is used to provide hydrogen fluoride to the fluorination reactor, and at the same time provide a circulation path for hydrogen fluoride during the fluorination reaction process; the HF heater, the HF heater is respectively connected to the fluorination reaction device and the buffer tank, and is used to heat hydrogen fluoride. The device and method for preparing fluoride from fluidized rare earth oxide provided by the present invention have the technical effect of realizing continuous and stable preparation of neodymium fluoride from neodymium oxide and ensuring the output and quality of neodymium oxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of a device for producing fluoride from fluidized rare earth oxides proposed in the present invention.

[0027] Figure 2 The present invention provides a specific flow chart of a method for preparing fluoride from fluidized rare earth oxides.

[0028] In the figure: 1. quantitative feeding device; 11. hopper; 12. loss-in-weight scale; 13. rotary air lock; 2. preheating device; 21. preheating tank; 22. ash discharge valve a; 3. fluorination reaction device; 31. fluorination reactor; 32. ash discharge valve b; 4. cooling tank; 5. tail gas treatment system; 51. GGH flue gas heat exchanger; 52. condenser; 53. bag filter; 54. induced draft fan; 6. gas distribution system; 61. buffer tank; 62. vent valve; 63. pressure reducing valve; 64. blower; 7. HF heater. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] The present invention discloses a device and method for preparing fluoride from fluidized rare earth oxide, which are mainly used in the scenario of fluoride preparation.

[0031] Reference Figure 1 , a fluidized rare earth oxide preparation fluoride device, comprising:

[0032] The quantitative feeding device 1 comprises a hopper 11, a loss-in-weight scale 12, and a rotary air lock 13. The loss-in-weight scale 12 is arranged on the outer wall of the bottom end of the hopper 11, and the rotary air lock 13 is arranged on the inner wall of the bottom end of the hopper 11;

[0033] Preheating device 2, the preheating device 2 includes a preheating tank 21 and an ash discharge valve a22, the input end of the preheating device 2 is connected to the bottom end of the quantitative feeding device 1, and the rotary air lock 13 is located between the preheating device 2 and the quantitative feeding device 1, and the ash discharge valve a22 is located between the preheating tank 21 and the fluorination reaction device 3;

[0034] The fluorination reaction device 3 includes a fluorination reactor 31 and an ash discharge valve b32. The input end of the fluorination reaction device 3 is connected to the output end of the ash discharge valve a22 provided on the preheating device 2, and the ash discharge valve b32 is provided between the fluorination reactor 31 and the cooling tank 4. The fluorination reactor 31 is in a dispersed fluidization / bubbling fluidization state and is provided with a hood and an air distribution plate. The fluorination reactor 31 is used for the reaction of rare earth oxides and hydrogen gas. The ash discharge valve b32 is located between the fluorination reactor 31 and the cooling tank 4.

[0035] A cooling tank 4, the input end of which is connected to the output end of the fluorination reaction device 3, and is used to cool the high-temperature fluoride;

[0036] The tail gas treatment system 5 is connected to the fluorination reaction device 3, and the tail gas treatment system 5 includes a GGH flue gas heat exchanger 51, a condenser 52, a bag dust collector 53 and an induced draft fan 54, and the GGH flue gas heat exchanger 51, the condenser 52, the bag dust collector 53 and the induced draft fan 54 are connected in sequence;

[0037] A gas distribution system 6, which includes a buffer tank 61, a vent valve 62, a pressure reducing valve 63 and a blower 64, and the vent valve 62, the pressure reducing valve 63 and the blower 64 are connected to the buffer tank 61 at the same time. The gas distribution system 6 is used to provide hydrogen fluoride to the fluorination reactor 31 and provide a circulation path for hydrogen fluoride during the fluorination reaction;

[0038] HF heater 7, HF heater 7 is connected to fluorination reaction device 3 and buffer tank 61 respectively, and is used for heating hydrogen fluoride;

[0039] Rare earth oxides are quantitatively fed under the action of the weight loss scale 12 and enter the preheating tank 21 and the fluorination reactor 31 through the hopper 11; the rare earth oxides are heated in the preheating tank 21, and hydrogen fluoride gas is introduced into the fluorination reactor 31 at the same time. The rare earth oxides are dispersed fluidized / bubbled fluidized under the action of hydrogen fluoride gas, and the hydrogen fluoride gas fully contacts the oxides and undergoes a fluorination reaction to generate fluoride and water vapor. After the fluorination reaction time is met, the rare earth oxides are discharged into the cooling tank 4 through the ash discharge valve b32; the high-temperature fluoride is cooled in the cooling tank 4 through the water-cooling jacket to obtain the finished fluoride; and the residual hydrogen fluoride and water vapor in the fluorination reactor 3 enter the tail gas treatment system 5. After being cooled by the GGH flue gas heat exchanger 51 and the condenser 52 in sequence, most of the water vapor condenses and flows out, and the flue gas enters the bag filter 53 for filtration. The filtered dust remains in the bag filter 53. Since the concentration of hydrogen fluoride in the flue gas is relatively high, in order to save costs and make full use of resources, the flue gas is sent to the buffer tank 61 through the induced draft fan 54, and at the same time, it is sent back to the fluorination reactor 3 through the gas distribution system 6 and the HF heater 7 to participate in the reaction, so as to realize the recycling of HF gas. Under this structure, on the one hand, the recycling of hydrogen fluoride gas is realized, saving costs, and on the other hand, the continuous and stable preparation of fluoride from rare earth oxides is realized, ensuring the output and quality of fluoride.

[0040] Reference Figure 2 , a method for preparing fluoride by fluidizing rare earth oxide, comprising the following specific steps:

[0041] S1: Rare earth oxide enters the preheating tank 21 and the fluorination reactor 31 from the hopper 11;

[0042] S2: The rare earth oxide is heated in the preheating tank 21, and hydrogen fluoride gas is introduced into the fluorination reactor 31. The oxide is subjected to dispersed fluidization / bubbling fluidization under the action of hydrogen fluoride gas, and the hydrogen fluoride gas fully contacts the oxide and undergoes a fluorination reaction to generate fluoride and water vapor;

[0043] S3: After the fluorination reaction time is met, the ash discharge valve b32 at the bottom of the fluorination reactor 31 is unloaded into the cooling tank 4, and at the same time, the ash discharge valve a22 at the bottom of the preheating device is opened, and the preheated high-temperature rare earth oxide enters the fluorination reactor 31. By adjusting the frequencies of the ash discharge valve a22 and the ash discharge valve b32, the material amount is kept stable;

[0044] S4: The high-temperature fluoride produced during the fluorination reaction enters the cooling tank 4 for cooling to obtain a finished fluoride;

[0045] S5: The residual hydrogen fluoride and water vapor in the fluorination reactor 31 enter the tail gas treatment system 5, and are cooled in the GGH flue gas heat exchanger 51 and the condenser 52 in sequence, and most of the water vapor condenses and flows out;

[0046] S6: The flue gas generated after being treated by the exhaust gas treatment system 5 enters the bag filter 53 for filtration;

[0047] S7: The filtered flue gas is sent into the buffer tank 61 through the induced draft fan 54;

[0048] S8: The flue gas in the buffer tank 61 is then sent back into the fluorination reactor 31 through the gas distribution system 6 and the HF heater 7 to participate in the reaction.

[0049] Working principle: Rare earth oxides enter the preheating tank 21 and the fluorination reactor 31 from the quantitative feeding device 1. The rare earth oxides are heated in the preheating tank 21. At the same time, hydrogen fluoride gas is introduced into the fluorination reactor 31. The rare earth oxides are dispersed fluidized / bubbled fluidized. The rare earth oxides react with hydrogen fluoride to generate fluoride and water vapor. The high-temperature fluoride then enters the cooling tank 4 below. After being cooled by the water-cooling jacket, the finished product neodymium fluoride is obtained. The residual hydrogen fluoride and water vapor in the fluorination reaction device 3 enter the exhaust gas treatment system 5, and pass through the GGH flue gas heat exchanger 51, the condenser 5 After cooling, most of the water vapor condenses and flows out, and the flue gas enters the bag filter 53 for filtration. The filtered dust remains in the bag filter 53. Since the concentration of hydrogen fluoride in the flue gas is relatively high, in order to save costs and make full use of resources, the flue gas is sent to the buffer tank 61 through the induced draft fan 54, and at the same time, it is sent back to the fluorination reaction device 3 through the gas distribution system 6 and the HF heater 7 to participate in the reaction, so as to realize the recycling of HF gas. Under this structure, on the one hand, the recycling of hydrogen fluoride gas is realized to save costs, and on the other hand, the continuous and stable preparation of neodymium fluoride from neodymium oxide is realized to ensure the output and quality of neodymium fluoride.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for preparing fluoride from fluidized rare earth oxide, characterized in that: include: A quantitative feeding device (1), the quantitative feeding device (1) comprising a hopper (11), a loss-in-weight scale (12), and a rotary air lock (13), the loss-in-weight scale (12) being arranged on the outer wall of the bottom end of the hopper (11), and the rotary air lock (13) being arranged on the inner wall of the bottom end of the hopper (11); A preheating device (2), the preheating device (2) comprising a preheating tank (21) and an ash discharge valve a (22), the input end of the preheating device (2) being connected to the bottom end of the quantitative feeding device (1), the rotary air lock (13) being located between the preheating device (2) and the quantitative feeding device (1), and the ash discharge valve a (22) being located between the preheating tank (21) and the fluorination reaction device (3); A fluorination reaction device (3), the fluorination reaction device (3) comprising a fluorination reactor (31) and an ash discharge valve b (32), the input end of the fluorination reaction device (3) being connected to the output end of an ash discharge valve a (22) provided on a preheating device (2), and the ash discharge valve b (32) being provided between the fluorination reactor (31) and a cooling tank (4), the fluorination reactor (31) being in a dispersed fluidization / bubbling fluidization state, and being provided with a hood and an air distribution plate, the fluorination reactor (31) being used for the reaction of rare earth oxides and hydrogen gas, and the ash discharge valve b (32) being located between the fluorination reactor (31) and the cooling tank (4); A cooling tank (4), the input end of which is connected to the output end of the fluorination reaction device (3) and is used to cool the high-temperature fluoride; An exhaust gas treatment system (5), wherein the exhaust gas treatment system (5) is connected to the fluorination reaction device (3), and the exhaust gas treatment system (5) comprises a GGH flue gas heat exchanger (51), a condenser (52), a bag dust collector (53) and an induced draft fan (54), and the GGH flue gas heat exchanger (51), the condenser (52), the bag dust collector (53) and the induced draft fan (54) are connected in sequence; A gas distribution system (6), the gas distribution system (6) comprising a buffer tank (61), a vent valve (62), a pressure reducing valve (63) and a blower (64), wherein the vent valve (62), the pressure reducing valve (63) and the blower (64) are connected to the buffer tank (61) at the same time, and the gas distribution system (6) is used to provide hydrogen fluoride to the fluorination reactor (31) and provide a circulation path for hydrogen fluoride during the fluorination reaction; An HF heater (7), wherein the HF heater (7) is connected to the fluorination reaction device (3) and the buffer tank (61) respectively, and is used for heating hydrogen fluoride.

2. A method for preparing fluoride by fluidizing rare earth oxide, applied to the device for preparing fluoride by fluidizing rare earth oxide according to claim 1, characterized in that: The specific steps include: S1: Rare earth oxides enter the preheating tank (21) and the fluorination reactor (31) from the hopper (11); S2: The rare earth oxide is heated in the preheating tank (21) and hydrogen fluoride gas is introduced into the fluorination reactor (31). The oxide is subjected to dispersed fluidization / bubbling fluidization under the action of the hydrogen fluoride gas. The hydrogen fluoride gas fully contacts the oxide and undergoes a fluorination reaction to generate fluoride and water vapor. S3: After the fluorination reaction time is met, the ash discharge valve b (32) at the bottom of the fluorination reactor (31) is unloaded into the cooling tank (4), and at the same time, the ash discharge valve a (22) at the bottom of the preheating device is opened, and the preheated high-temperature rare earth oxide enters the fluorination reactor (31). By adjusting the frequency of the ash discharge valve a (22) and the ash discharge valve b (32), the material amount is kept stable; S4: The high-temperature fluoride produced during the fluorination reaction enters a cooling tank (4) for cooling to obtain a finished fluoride; S5: The residual hydrogen fluoride and water vapor in the fluorination reactor (31) enter the tail gas treatment system (5), and are cooled in the GGH flue gas heat exchanger (51) and the condenser (52) in sequence, and most of the water vapor condenses and flows out; S6: The flue gas generated after being treated by the tail gas treatment system (5) enters the bag filter (53) for filtration; S7: The filtered flue gas is sent into the buffer tank (61) through the induced draft fan (54); S8: The flue gas in the buffer tank (61) is then sent back into the fluorination reactor (31) through the gas distribution system (6) and the HF heater (7) to participate in the reaction.

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