Device and method for efficient clean utilization of fluor carbon cerite double chlorination method
By combining a multi-stage continuous packed bed and a spiral propulsion condenser device with "oxygen-rich and oxygen-deficient" combustion and alumina chlorination reaction, the environmental pollution and high rare earth loss rate problems in the extraction of rare earth elements from fluorocarbon cerium ore in the existing technology have been solved, realizing efficient and clean rare earth extraction and simultaneous extraction of associated elements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHEASTERN UNIV CHINA
- Filing Date
- 2023-09-25
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for extracting rare earth elements from bastnaesite are complex, generate significant amounts of waste gas, waste liquid, and waste residue, leading to environmental pollution and high rare earth loss rates.
The system employs a multi-stage continuous packed bed and a spiral propulsion condenser device. High-temperature carbon monoxide flue gas generated by "oxygen-rich and oxygen-deficient" combustion is used as a heat source and carbon source. It combines alumina with rare earth minerals to carry out a chlorination reaction. The chlorination products are separated by a multi-stage condenser, achieving efficient and clean extraction of rare earth elements. High-purity rare earth chlorides are obtained through water leaching separation.
It achieves efficient and clean utilization of rare earth elements, reduces the generation of waste liquid, waste gas and waste residue, improves heat utilization efficiency, extracts associated elements simultaneously, and achieves a rare earth recovery rate of up to 99.9%.
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Figure CN117488062B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of rare earth comprehensive utilization and recycling, specifically relating to an apparatus and method for the efficient and clean utilization of fluorocarbon cerium ore by the double chlorination process. Background Technology
[0002] Baustenite is a cerium group rare earth element (light rare earth) mineral with significant industrial value, belonging to the fluorocarbonate type. Its rare earth element content (calculated as RE₂O₃) is generally 75%. It belongs to the hexagonal crystal system, with crystals occurring in tabular form, usually as fine-grained aggregates. It is yellow, light green, or brown. It has a vitreous or greasy luster. Its hardness is 4–4.5. Its density is 4.72–5.12 g / cm³. 3 It is radioactive and weakly magnetic. It dissolves in dilute hydrochloric acid and sulfuric acid, and decomposes rapidly in phosphoric acid. It is mainly found in alkaline rocks, alkaline pegmatites, and related hydrothermal deposits. It is an important mineral raw material for extracting rare earth elements such as cerium and lanthanum, as well as rare earth compounds. Rare earth chlorides can be extracted from fluorocarbon cerium concentrate using the hydrochloric acid-sodium hydroxide decomposition method; europium oxide and cerium oxide, among other rare earth oxides, can be produced using the oxidative roasting-acid leaching method. Fluorocarbon cerium concentrate can also be directly used to produce polishing powder.
[0003] Existing technologies for extracting rare earth elements from bastnaesite mainly include concentrated sulfuric acid decomposition, alkaline decomposition, and chlorination decomposition. Sulfuric acid decomposition and alkaline decomposition are complex processes that generate large amounts of waste gas, waste liquid, and waste residue, posing significant environmental hazards. Furthermore, the separation of residue and liquid is difficult, resulting in a high rare earth loss rate. Summary of the Invention
[0004] To address the problems existing in the prior art, the primary objective of this invention is to disclose a device for the efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process. The device is characterized by primarily comprising: a primary continuous packed bed, a piping system, a secondary continuous packed bed, a tertiary continuous packed bed, a primary spiral propeller condenser, and a secondary spiral propeller condenser. The outlet of the primary continuous packed bed is connected to the inlet of the secondary continuous packed bed via a pipe; the outlet of the secondary continuous packed bed is connected to the inlet of the tertiary continuous packed bed; the outlet of the tertiary continuous packed bed is connected to the inlet of the primary spiral propeller condenser; the outlet of the primary spiral propeller condenser is connected to the inlet of the secondary spiral propeller condenser; and the outlet of the secondary spiral propeller condenser is connected to a flue gas recovery device via a pipe. The condensed flue gas is then sent to the flue gas recovery device for recycling.
[0005] The continuous packed bed consists of a feeder, a furnace body, an air inlet, an air outlet, and a slag discharge outlet; wherein, the feeder, air inlet, air outlet, and slag discharge outlet are connected to the furnace body via pipelines using quick-release flanges; the feeder and slag discharge outlet are connected by internal airlocks to achieve continuous unidirectional feeding or discharging of solids.
[0006] The spiral propulsion condenser consists of a central shaft, spiral blades, a motor, a discharge port, a gas outlet, and a tank. Spiral blades are welded to the central shaft, with a 5mm distance between the outer edge of the blades and the inner wall of the condenser. The rotation speed of the spiral blades is continuously adjustable within the range of 0-100 rpm, preventing anhydrous chloride from adhering to the wall surface during condensation. The central shaft of the spiral propulsion condenser has a hollow structure, ensuring that flue gas leaves the condenser through an internal channel. An airlock structure is installed in the discharge port at the bottom of the condenser to ensure continuous discharge and encapsulation of anhydrous chloride powder. The condensation recovery efficiency of anhydrous chloride is greater than 99%, and the water absorption rate of anhydrous chloride is less than 0.1%.
[0007] The first-stage spiral propeller condenser is controlled at a temperature of 250–300℃ to obtain crude ferric chloride; the second-stage spiral propeller condenser is controlled at a temperature of 0–50℃ to obtain crude silicon tetrachloride and titanium chloride.
[0008] Another objective of this invention is to disclose a method for the efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process, achieved using the aforementioned apparatus, specifically comprising:
[0009] (1) The first-stage continuous packed bed obtains high-temperature carbon monoxide flue gas through "oxygen-enriched and oxygen-deficient" combustion, which serves as a heat source and carbon source; in the second-stage continuous packed bed, alumina reacts with the high-temperature carbon monoxide flue gas obtained from "oxygen-enriched and oxygen-deficient" combustion and excess chlorine to produce a mixed gas composed of aluminum chloride, carbon monoxide, chlorine and carbon dioxide; in the third-stage continuous packed bed, rare earth ore reacts with aluminum chloride, carbon monoxide and chlorine produced by the second-stage continuous packed bed to produce a chlorination reaction.
[0010] (2) The rare earth chlorides, aluminum fluoride and alkaline earth metal chlorides generated by the chlorination reaction remain in the chlorination slag in solid form and are discharged from the solid outlet of the three-stage continuous packing. The chlorides containing titanium tetrachloride, silicon tetrachloride and ferric chloride leave the continuous packing bed in gas form and enter the spiral propulsion condenser.
[0011] (3) The gaseous products obtained by chlorination are condensed and separated by a multi-stage spiral propulsion condenser after heat exchange. The temperature of the first-stage spiral propulsion condenser is controlled at 250-300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propulsion condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained by condensation is mainly unreacted chlorine gas, which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse.
[0012] (4) The solid products generated by the chlorination reaction, including rare earth chlorides, aluminum fluoride and alkaline earth metal chlorides, are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chlorides and alkaline earth metal chlorides (calcium chloride and magnesium chloride). The mixed solution is extracted and separated to obtain a single rare earth chloride with a mass fraction greater than 99.9%.
[0013] The rare earth ore is bastnaesite, in which the mass fraction of rare earth elements is greater than 60%; the batching scheme is as follows: by mass ratio, carbon monoxide: bastnaesite = (0.1~5):1; alumina: bastnaesite = (0.1~3):1.
[0014] "Oxygen-enriched and oxygen-deficient" combustion refers to the oxygen-deficient combustion of carbon monoxide and oxygen in a gas-fired boiler, producing high-temperature flue gas containing carbon monoxide and carbon dioxide. This flue gas serves as the heat and carbon source for the chlorination reaction. The mass ratio of carbon monoxide in the resulting flue gas is: (alumina + rare earth minerals) = (1-4):1; the stoichiometric formula is:
[0015] mCO + nO2 = (m - 2n)CO + 2nCO2;
[0016] Alumina reacts with carbon monoxide and chlorine in the high-temperature flue gas generated by a primary continuous packed bed to produce a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, and carbon dioxide. This mixed gas serves as the chlorinating agent, carbon source, and fluorine and phosphorus fixation agent in the chlorination reaction. The chlorination reaction temperature is 600–1000℃, and the reaction time is 50–120 min. An appropriate amount of oxygen is added during the rare earth chlorination process to react with carbon monoxide and maintain the thermal equilibrium of the carbothermic chlorination reaction within the system. Taking alumina as an example, the stoichiometric formula is:
[0017] xAl2O3(s)+(3x+n)CO(g)+(3x+m)Cl2(g)=2xAlCl3(g)+3xCO2+n CO(g)+m Cl2(g)
[0018] Rare earth ore undergoes a chlorination reaction with the mixed gas obtained in the first step, producing rare earth chlorides and other chlorides. Fluorine in the rare earth is converted to aluminum fluoride. The chlorination reaction temperature is 600–1200℃, and the reaction time is 30–120 min. The stoichiometric formula is:
[0019] (1) For bastnaesite:
[0020] CeFCO3(s)+CO(g)+Cl2(g)+1 / 3 AlCl3(g)=CeCl3(s,l)+2CO2(g)+1 / 3 AlF3(s)
[0021] (2) For calcium fluoride:
[0022] 3 / 2 CaF2(s)+AlCl3(s)=3 / 2 CaCl2(s,l)+AlF3(s)
[0023] (3) For silicon dioxide:
[0024] 3SiO2(s)+4AlCl3(g)=2Al2O3(s)+3SiCl4(g)
[0025] SiO2(s)+2CO(g)+2Cl2(g)=SiCl4(g)+2CO2(g)
[0026] The apparatus and method for the efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process, as described in this invention, offer the following advantages compared to existing technologies:
[0027] (1) The multi-stage continuous packed bed device used in this invention realizes the efficient and clean utilization of fluorocarbon cerium ore by the double chlorination process. The feed airlock and discharge airlock enable the continuous operation of multi-stage reactions. The spiral propulsion condenser is used to prevent the anhydrous chloride from adhering to the wall surface during condensation, ensuring the continuous discharge and packaging of anhydrous chloride powder. The condensation recovery efficiency of anhydrous chloride is greater than 99%, and the water absorption rate of anhydrous chloride is less than 0.1%.
[0028] (2) The present invention uses carbon monoxide and oxygen to produce high-temperature flue gas containing carbon monoxide and carbon dioxide through anaerobic combustion in a gas-fired boiler, which serves as the heat source and carbon source for the chlorination reaction, resulting in high heat utilization efficiency; the invention employs a two-step process of alumina chlorination and rare earth chlorination, which reduces the cost of obtaining aluminum chloride and improves heat utilization efficiency.
[0029] (3) This invention not only realizes the extraction of rare earth elements, but also simultaneously extracts associated elements such as titanium, silicon, iron, calcium, and magnesium from the ore. At the same time, no waste acid or alkali liquid is generated during the rare earth utilization process, and chlorine and carbon dioxide are recycled, avoiding the generation of waste liquid, waste gas, and waste residue in traditional methods. Attached Figure Description
[0030] Figure 1 This is a process flow for the efficient and clean utilization of fluorocarbon cerium ore via a double chlorination method.
[0031] Figure 2 Schematic diagram of a multi-stage continuous packed bed device and a multi-stage spiral propulsion condenser device;
[0032] 1-1 Feeder, 1-2 Furnace body, 1-3 Air inlet, 1-4 Air outlet, 1-5 Slag discharge port, 5-1 Central shaft, 5-2 Spiral blades, 5-3 Motor, 5-4 Discharge port, 5-5 Air outlet, 5-6 Tank body. Detailed Implementation
[0033] The present invention will be further described in detail below with reference to the embodiments.
[0034] The bastnaesite used in the embodiments of this invention has the following main components: REO-62.58%, CO2-12.35%, F-7.53%, Al2O3-0.15%, MgO-0.13%, CaO-8.25%, Fe2O3-0.25%, and Others-8.76%.
[0035] Example 1
[0036] A device for the efficient and clean utilization of fluorocarbon cerium ore via a dual chlorination process, such as... Figure 2 As shown, it mainly consists of a primary continuous packed bed 1, a piping device 2, a secondary continuous packed bed 3, a tertiary continuous packed bed 4, a primary spiral propulsion condenser 5, and a secondary multi-stage spiral propulsion condenser 6. The outlet of the primary continuous packed bed 1 is connected to the inlet of the secondary continuous packed bed 3 via a pipe; the outlet of the secondary continuous packed bed 3 is connected to the inlet of the tertiary continuous packed bed 4; the outlet of the tertiary continuous packed bed 4 is connected to the inlet of the primary spiral propulsion condenser 5; the outlet of the primary spiral propulsion condenser 5 is connected to the inlet of the secondary spiral propulsion condenser 6; and the outlet of the secondary spiral propulsion condenser 6 is connected to a flue gas recovery device via a pipe. The condensed flue gas is then sent to the flue gas recovery device for recovery.
[0037] The continuous packed bed consists of a feeder, a furnace body, an air inlet, an air outlet, and a slag discharge port; wherein the feeder, air inlet, air outlet, and slag discharge port are connected to the furnace body via pipelines using quick-release flanges; the feeder and slag discharge port are connected by internal airlocks to achieve continuous unidirectional feeding or discharging of solids.
[0038] The spiral propulsion condenser consists of a central shaft, spiral blades, a motor, a discharge port, a gas outlet, and a tank. Spiral blades are welded to the central shaft, with a 5mm distance between the outer edge of the blades and the inner wall of the condenser. The rotation speed of the spiral blades is continuously adjustable within the range of 0-100 rpm, preventing anhydrous chloride from adhering to the wall surface during condensation. The central shaft of the spiral propulsion condenser has a hollow structure, ensuring that flue gas leaves the condenser through an internal channel. An airlock structure is installed in the discharge port at the bottom of the condenser to ensure continuous discharge and encapsulation of anhydrous chloride powder. The condensation recovery efficiency of anhydrous chloride is greater than 99%, and the water absorption rate of anhydrous chloride is less than 0.1%.
[0039] The above-mentioned apparatus is used to process fluorocarbon cerium ore, such as Figure 1 As shown, the specific steps are as follows:
[0040] (1) The primary continuous packed bed obtains high-temperature carbon monoxide flue gas through "oxygen-enriched and oxygen-deficient" combustion, which serves as a heat source and carbon source. By mass ratio, the carbon monoxide:(alumina + bastnaesite) ratio in the high-temperature flue gas produced by the primary continuous packed bed is 1:1. In the secondary continuous packed bed, alumina reacts with the high-temperature carbon monoxide flue gas obtained from "oxygen-enriched and oxygen-deficient" combustion and excess chlorine at 1000℃ for 5 minutes, resulting in a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, and carbon dioxide, with an alumina:bastnaesite ratio of 0.1:1. In the tertiary continuous packed bed, rare earth minerals react with aluminum chloride, carbon monoxide, and chlorine produced by the secondary continuous packed bed at 600℃ for 30 minutes. The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc., generated by the chlorination reaction remain in the chlorination slag in solid form, while titanium tetrachloride, silicon tetrachloride, ferric chloride, etc., leave the chlorination furnace in gaseous form.
[0041] (2) The gaseous products obtained by chlorination are condensed and separated by a two-stage spiral propulsion condenser after heat exchange. The temperature of the first-stage spiral propulsion condenser is controlled at 300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propulsion condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained by condensation is mainly unreacted chlorine gas, which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse.
[0042] (3) The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc. generated by the chlorination reaction remain in the chlorination residue in solid form. The solid products are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chloride and alkaline earth metal chloride. The mixed solution is separated by extraction to obtain a single rare earth chloride with a mass fraction greater than 99.9%.
[0043] Example 2
[0044] The apparatus of Example 1 is used to process bastnaesite, and the specific steps are as follows:
[0045] (1) The primary continuous packed bed obtains high-temperature carbon monoxide flue gas through "oxygen-enriched and oxygen-deficient" combustion, which serves as a heat source and carbon source. The mass ratio of carbon monoxide to (alumina + bastnaesite) in the high-temperature flue gas produced by the primary continuous packed bed is 4:1. In the secondary continuous packed bed, alumina reacts with the high-temperature carbon monoxide flue gas obtained from "oxygen-enriched and oxygen-deficient" combustion and excess chlorine at 600°C for 60 minutes, resulting in a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, and carbon dioxide, with an alumina to bastnaesite ratio of 3:1. In the tertiary continuous packed bed, rare earth minerals react with aluminum chloride, carbon monoxide, and chlorine produced by the secondary continuous packed bed at 600°C for 120 minutes. The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc., generated by the chlorination reaction remain in the chlorination slag in solid form, while titanium tetrachloride, silicon tetrachloride, ferric chloride, etc., leave the chlorination furnace in gaseous form.
[0046] (2) The gaseous products obtained from chlorination are condensed and separated by a two-stage spiral propulsion condenser after heat exchange. The temperature of the first-stage spiral propulsion condenser is controlled at 300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propulsion condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained from condensation is mainly unreacted chlorine gas, etc., which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse.
[0047] (3) The rare earth chlorides, aluminum fluoride and alkaline earth metal chlorides generated by the chlorination reaction remain in the chlorination residue in solid form. The solid products are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chloride and alkaline earth metal chloride. The mixed solution is separated by extraction to obtain a single rare earth chloride with a mass fraction greater than 99.9%.
[0048] Example 3
[0049] The apparatus of Example 1 is used to process bastnaesite, and the specific steps are as follows:
[0050] (1) The first-stage continuous packed bed obtains high-temperature carbon monoxide flue gas through "oxygen-enriched and oxygen-deficient" combustion, which serves as a heat source and carbon source. By mass ratio, the carbon monoxide:(alumina + bastnaesite) ratio in the high-temperature flue gas produced by the first-stage continuous packed bed is 2:1. In the second-stage continuous packed bed, alumina reacts with the high-temperature carbon monoxide flue gas obtained from "oxygen-enriched and oxygen-deficient" combustion and excess chlorine at 800℃ for 40 minutes, resulting in a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, carbon dioxide, etc., with an alumina:bastnaesite ratio of 0.8:1. In the third-stage continuous packed bed, rare earth minerals react with aluminum chloride, carbon monoxide, and chlorine produced by the second-stage continuous packed bed at 1000℃ for 30 minutes. The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc., generated by the chlorination reaction remain in the chlorination slag in solid form, while titanium tetrachloride, silicon tetrachloride, ferric chloride, etc., leave the chlorination furnace in gaseous form.
[0051] (2) The gaseous products obtained from chlorination are condensed and separated by a two-stage spiral propulsion condenser after heat exchange. The temperature of the first-stage spiral propulsion condenser is controlled at 300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propulsion condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained from condensation is mainly unreacted chlorine gas, etc., which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse.
[0052] (3) The rare earth chloride, aluminum fluoride, alkaline earth metal chloride and other products generated by the chlorination reaction remain in the chlorination residue in solid form. The solid products are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chloride and alkaline earth metal chloride. The mixed solution is separated by extraction to obtain a single rare earth chloride with a mass fraction greater than 99.9%.
[0053] Example 4
[0054] The apparatus of Example 1 is used to process bastnaesite, and the specific steps are as follows:
[0055] (1) The primary continuous packed bed obtains high-temperature carbon monoxide flue gas through "oxygen-enriched and oxygen-deficient" combustion, which serves as a heat source and carbon source. By mass ratio, the carbon monoxide:(alumina + bastnaesite) ratio in the high-temperature flue gas produced by the primary continuous packed bed is 3:1. In the secondary continuous packed bed, alumina reacts with the high-temperature carbon monoxide flue gas obtained from "oxygen-enriched and oxygen-deficient" combustion and excess chlorine at 700℃ for 60 minutes, resulting in a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, carbon dioxide, etc., with an alumina:bastnaesite ratio of 1.5:1. In the tertiary continuous packed bed, rare earth minerals react with aluminum chloride, carbon monoxide, and chlorine produced by the secondary continuous packed bed at 800℃ for 70 minutes. The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc., generated by the chlorination reaction remain in the chlorination slag in solid form, while titanium tetrachloride, silicon tetrachloride, ferric chloride, etc., leave the chlorination furnace in gaseous form.
[0056] (2) The gaseous products obtained from chlorination are condensed and separated by a two-stage spiral propulsion condenser after heat exchange. The temperature of the first-stage spiral propulsion condenser is controlled at 300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propulsion condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained from condensation is mainly unreacted chlorine gas, etc., which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse.
[0057] (3) The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc. generated by the chlorination reaction remain in the chlorination residue in solid form. The solid products are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chlorides and alkaline earth metal chlorides. The mixed solution is separated by extraction to obtain a single rare earth chloride with a mass fraction greater than 99.9%.
[0058] Example 5
[0059] The apparatus of Example 1 is used to process bastnaesite, and the specific steps are as follows:
[0060] (1) The primary continuous packed bed obtains high-temperature carbon monoxide flue gas through "oxygen-enriched and oxygen-deficient" combustion, which serves as a heat source and carbon source. By mass ratio, the carbon monoxide:(alumina + bastnaesite) ratio in the high-temperature flue gas produced by the primary continuous packed bed is 3:1. In the secondary continuous packed bed, alumina reacts with the high-temperature carbon monoxide flue gas obtained from "oxygen-enriched and oxygen-deficient" combustion and excess chlorine at 900℃ for 10 minutes, resulting in a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, carbon dioxide, etc., with an alumina:bastnaesite ratio of 2.5:1. In the tertiary continuous packed bed, rare earth minerals react with aluminum chloride, carbon monoxide, and chlorine produced by the secondary continuous packed bed at 950℃ for 80 minutes. The rare earth chlorides, aluminum fluoride, alkaline earth metal chlorides, etc., generated by the chlorination reaction remain in the chlorination slag in solid form, while titanium tetrachloride, silicon tetrachloride, ferric chloride, etc., leave the chlorination furnace in gaseous form.
[0061] (3) The gaseous products obtained from chlorination are condensed and separated by a two-stage spiral propulsion condenser after heat exchange. The temperature of the first-stage spiral propulsion condenser is controlled at 300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propulsion condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained from condensation is mainly unreacted chlorine gas, etc., which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse.
[0062] (4) The rare earth chlorides, aluminum fluoride and alkaline earth metal chlorides generated by the chlorination reaction remain in the chlorination residue in solid form. The solid products are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chloride and alkaline earth metal chloride. The mixed solution is separated by extraction to obtain a single rare earth chloride with a mass fraction greater than 99.9%.
Claims
1. A method for the efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process, characterized in that, This method is mainly implemented by a device consisting of a primary continuous packed bed, a piping system, a secondary continuous packed bed, a tertiary continuous packed bed, a primary spiral propulsion condenser, and a secondary spiral propulsion condenser. Specifically, the outlet of the primary continuous packed bed is connected to the inlet of the secondary continuous packed bed via a pipe; the outlet of the secondary continuous packed bed is connected to the inlet of the tertiary continuous packed bed; the outlet of the tertiary continuous packed bed is connected to the inlet of the primary spiral propulsion condenser; the outlet of the primary spiral propulsion condenser is connected to the inlet of the secondary spiral propulsion condenser; and the outlet of the secondary spiral propulsion condenser is connected to a flue gas recovery device via a pipe. The condensed flue gas is then sent to the flue gas recovery device for recovery. Includes the following steps: (1) The primary continuous packed bed obtains high-temperature carbon monoxide flue gas through oxygen-enriched and oxygen-deficient combustion, which serves as a heat source and carbon source; in the secondary continuous packed bed, alumina reacts with high-temperature carbon monoxide flue gas and excess chlorine to produce a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, and carbon dioxide; in the tertiary continuous packed bed, rare earth ore reacts with aluminum chloride, carbon monoxide, and chlorine produced in the secondary continuous packed bed; the rare earth ore is bastnaesite, wherein the mass fraction of rare earth elements is greater than 60%; (2) The rare earth chlorides, aluminum fluoride and alkaline earth metal chlorides generated by the chlorination reaction remain in the chlorination slag in solid form and are discharged from the solid outlet of the three-stage continuous packing. The chlorides containing titanium tetrachloride, silicon tetrachloride and ferric chloride leave the continuous packing bed in gas form and enter the spiral propulsion condenser. (3) The gaseous products obtained by chlorination are condensed and separated by a multi-stage spiral propeller condenser after heat exchange. The temperature of the first-stage spiral propeller condenser is controlled at 250~300℃ to obtain crude ferric chloride product. The temperature of the second-stage spiral propeller condenser is controlled at below 50℃ to obtain crude silicon tetrachloride and titanium chloride. The tail gas obtained by condensation is mainly unreacted chlorine gas, which is compressed to obtain liquid chlorine and returned to the chlorination cycle for reuse. (4) The solid products of rare earth chloride, aluminum fluoride and alkaline earth metal chloride generated by the chlorination reaction are separated by water leaching to obtain a mixed solution of aluminum fluoride solid and rare earth chloride and alkaline earth metal chloride. The mixed solution is extracted and separated to obtain a single rare earth chloride.
2. The method for efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process according to claim 1, characterized in that, The continuous packed bed consists of a feeder, a furnace body, an air inlet, an air outlet, and a slag discharge outlet; wherein, the feeder, air inlet, air outlet, and slag discharge outlet are connected to the furnace body via pipelines using quick-release flanges; the feeder and slag discharge outlet are connected by internal airlocks to achieve continuous unidirectional feeding or discharging of solids.
3. The method for efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process according to claim 1, characterized in that, The spiral propulsion condenser consists of a central shaft, spiral blades, a motor, a discharge port, a gas outlet, and a tank. The spiral blades are welded onto the central shaft of the spiral propulsion condenser to prevent anhydrous chloride from adhering to the wall surface during condensation. The interior of the central shaft of the spiral propulsion condenser is hollow, ensuring that the flue gas leaves the condenser through the internal channel of the central shaft. An airlock structure is installed in the discharge port at the bottom of the condenser to ensure the continuous discharge and encapsulation of anhydrous chloride powder.
4. The method for efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process according to claim 3, characterized in that, The distance between the outer edge of the spiral blade and the inner wall of the condenser is 5mm, and the rotation speed of the spiral blade is continuously adjustable within the range of 0~100rpm.
5. The method for efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process according to claim 1, characterized in that, Based on the mass ratio, the carbon monoxide : (alumina + rare earth minerals) in high-temperature carbon monoxide flue gas = (1~4):
1.
6. The method for efficient and clean utilization of fluorocarbon cerium ore via a double chlorination process according to claim 1, characterized in that, Alumina reacts with carbon monoxide and chlorine in the high-temperature flue gas generated by the primary continuous packed bed to produce a mixed gas composed of aluminum chloride, carbon monoxide, chlorine, and carbon dioxide. The reaction temperature is 600~1000℃ and the reaction time is 50~120min. Rare earth ore undergoes a chlorination reaction with the mixed gas obtained in the first step. The chlorination reaction temperature is 600~1200℃ and the reaction time is 30~120min.