WO2024093526A1 - 混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法 - Google Patents

混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法 Download PDF

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Publication number
WO2024093526A1
WO2024093526A1 PCT/CN2023/117725 CN2023117725W WO2024093526A1 WO 2024093526 A1 WO2024093526 A1 WO 2024093526A1 CN 2023117725 W CN2023117725 W CN 2023117725W WO 2024093526 A1 WO2024093526 A1 WO 2024093526A1
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Prior art keywords
cyclone separator
tank
leaching
discharge port
rare earth
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PCT/CN2023/117725
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English (en)
French (fr)
Inventor
高鹏
袁帅
宁继来
韩跃新
李艳军
孙永升
李文博
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东北大学
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Publication of WO2024093526A1 publication Critical patent/WO2024093526A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/02—Apparatus therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
    • C22B3/10—Hydrochloric acid, other halogenated acids or salts thereof
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/12—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic alkaline solutions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B59/00—Obtaining rare earth metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the invention relates to the fields of beneficiation and comprehensive resource recovery, and in particular to a system for mixed rare earth concentrate suspended ore phase conversion-clean leaching and a use method thereof.
  • the Bayan Obo type mixed rare earth ore is a rare earth mineral with iron-rare earth-niobium symbiosis unique to the Bayan Obo area of Inner Mongolia, my country.
  • the main rare earth components are fluorocarbon cerium ore and monazite. It has the characteristics of large reserves, complex types of associated ores, and high rare earth content. Because rare earth minerals are associated with a large amount of hematite and limonite and have similar mineral processing properties, the symbiotic relationship is relatively close, so it is difficult to obtain high-grade rare earth concentrates by conventional mineral processing methods.
  • the main means of processing Bayan Obo type mixed rare earth ore is concentrated sulfuric acid roasting process, which has the advantages of low requirements for rare earth feed grade, relatively simple process, short operation process, and is conducive to large-scale production; but the main defects of this method are also obvious: wastewater, waste gas and solid waste pollute the surrounding environment, and the thorium pyrophosphate produced by high-temperature roasting is difficult to recycle and must be sealed, which not only occupies a large amount of land, but also brings hidden dangers to the surrounding environment; another method for processing this type of Bayan Obo type mixed rare earth ore is alkali decomposition method, compared with concentrated sulfuric acid decomposition method, its production method is cleaner and the comprehensive resource recovery efficiency is higher; but it also has problems such as high requirements for concentrate grade, discontinuous operation process, low leaching efficiency, large alkali consumption, and serious equipment corrosion, which makes it difficult to apply industrially.
  • Patent CN111926181A discloses a method for distributed recovery of valuable components in rare earth concentrates.
  • the mixed rare earth concentrate is roasted with fluidized air and then dissolved in hydrochloric acid to obtain a cerium-poor rare earth chloride solution and a thorium-containing cerium-rich slag.
  • the cerium-rich slag is decomposed by alkaline solution to further recover F, P and cerium and thorium. This method realizes the comprehensive recovery of valuable elements in the mixed rare earth concentrate.
  • Patent CN109136590A discloses a decomposition treatment process for a Baotou mixed rare earth concentrate, which uses a dilute hydrochloric acid graded countercurrent optimal leaching method to treat the mixed rare earth concentrate after oxidative roasting to obtain a low-acidity cerium-less rare earth chloride solution and hydrochloric acid optimal leaching residue, thereby avoiding the coordination leaching of Ce 4+ and F in the hydrochloric acid leaching process of fluorocarbon cerium ore after oxidative roasting; however, the process has the disadvantages of a relatively complex leaching process and a relatively slow leaching rate.
  • the present invention provides a system for suspended phase transformation-clean leaching of mixed rare earth concentrate and a method for using the system, which can realize low-temperature phase transformation of rare earth minerals and avoid the formation of tetravalent cerium in the phase transformation products. It can improve the rare earth leaching rate and prevent the generation of fluorine and chlorine waste gases at the same time.
  • a system for mixed rare earth concentrate suspension phase conversion-clean leaching of the present invention comprises:
  • the feed bin is connected with the venturi dryer
  • the top discharge port of the venturi dryer is connected with the feed port of the first cyclone separator through a pipeline
  • the bottom discharge port of the first cyclone separator is connected with the second cyclone separator
  • the bottom discharge port of the second cyclone separator is connected with the suspension preheating decomposition furnace
  • the top discharge port of the suspension preheating decomposition furnace is connected with the feed port of the third cyclone separator through a pipeline
  • the bottom discharge port of the third cyclone separator is connected with the first fluidizing sealing valve
  • the first fluidizing sealing valve is matched with the mineral phase converter
  • the discharge port of the mineral phase converter is connected with the second fluidizing sealing valve
  • the discharge port of the second fluidizing sealing valve is connected with the feed port of the fifth cyclone separator
  • the bottom discharge port of the fifth cyclone separator is opposite to the water cooling tank
  • the water cooling tank is opposite to the ball mill
  • the discharge port of the ball mill is connected with the feed
  • the above system also includes a screw feeder and a feeding belt.
  • the discharge port of the feeding bin is opposite to the feed port of the screw feeder, the discharge port of the screw feeder is opposite to the feeding belt, and the discharge end of the feeding belt is opposite to the feed port of the Venturi dryer.
  • a main burner is arranged at the bottom of the suspension preheating decomposition furnace, and the main burner is connected to a reducing gas source and an air source through a pipeline.
  • the reducing gas is H2 and/or CO.
  • the top of the first cyclone separator is connected to the electrostatic precipitator through a pipeline, the electrostatic precipitator is connected to the tail gas absorption station, the tail gas absorption station and the induced draft fan cooperate, and the induced draft fan is connected to the chimney through a pipeline;
  • the discharge port of the electrostatic precipitator is connected to the feed port of the pneumatic lift pump, the pneumatic lift pump is connected to the ash return fan, and the discharge port of the pneumatic lift pump is connected to the third cyclone separator through a pipeline;
  • a sixth cyclone separator is further provided, the bottom discharge port of the fifth cyclone separator is connected to the sixth cyclone separator through a pipeline, and a second ash hopper is provided on the connecting pipeline, the top discharge port of the sixth cyclone separator is connected to the fifth cyclone separator through a pipeline, the top discharge port of the fifth cyclone separator is connected to the third cyclone separator through a pipeline, the top discharge port of the third cyclone separator is connected to the second cyclone separator through a pipeline, and the top discharge port of the second cyclone separator is connected to the Venturi dryer through a pipeline; and a dry heat generator and a first ash hopper are provided on the connecting pipeline, wherein the dry heat generator is connected to a reducing gas source through a pipeline, and the reducing gas source is selected from H2 and/or CO;
  • the first fluidized sealing valve and the second fluidized sealing valve are both provided with air inlets at the bottom and are connected to the nitrogen gas source pipeline;
  • an air inlet is provided at the bottom of the mineral phase converter and is connected to the nitrogen gas source pipeline
  • a ventilation port is provided at the top of the mineral phase converter and is connected to the fourth cyclone separator; the bottom discharge port of the fourth cyclone separator is connected to the mineral phase converter, and the fourth The top discharge port of the cyclone separator is connected to the suspension preheating decomposition furnace.
  • the main function of the mineral phase converter is to provide a fluidized reduction chamber for mineral powder to achieve efficient mineral phase conversion.
  • Its main body includes a mineral phase converter shell, forming a reduction chamber, and a mineral phase conversion feed port and a mineral phase conversion discharge port are arranged on the shell.
  • a plurality of top baffles are arranged at intervals on the inner side of the shell located above, and a plurality of second bottom baffles are arranged staggered on the inner side of the shell located below, and a first bottom baffle is arranged directly below the top baffle, and a gap is left between the first bottom baffle and the corresponding top baffle.
  • top baffle and the first bottom baffle and the second bottom baffle together constitute a mineral powder flow channel, and the space formed between the top baffle and the second bottom baffle is a vertical channel; a mineral phase conversion air distribution plate is arranged on the shell on one side of the first bottom baffle and the second bottom baffle to evenly distribute the airflow; a mineral phase conversion air inlet is arranged in each vertical channel to provide loosening wind and fluidizing wind required for stable flow of mineral powder.
  • the main function of the first fluidized sealing valve and the second fluidized sealing valve is to isolate the gas introduced with the mineral powder in the previous stage.
  • Its main body includes a fluidized sealing shell, which forms a fluidized chamber, a top fluidized sealing baffle is arranged above the fluidized chamber, a bottom fluidized sealing baffle is arranged directly below the top fluidized sealing baffle, and a fluidized sealing air distribution plate is arranged on one side of the bottom fluidized sealing baffle for evenly distributing the airflow; a nitrogen inlet is arranged in each vertical channel to provide loosening air and fluidizing air required for the stable flow of mineral powder.
  • the discharge port of the ball mill is connected to the feed port of the spiral classifier
  • the overflow port of the spiral classifier is connected to the feed port of the first acid leaching tank through a pipeline
  • the sand return port of the spiral classifier is connected to the ball mill.
  • the first acid leaching tank drain port is connected to the second acid leaching tank through a pipeline
  • the above system further includes a first filter press, the discharge port of the first acid leaching tank is opposite to the first filter press, the discharge port of the first filter press is connected to the alkaline leaching tank, and the discharge port below the first filter press is connected to the second acid leaching tank through a pipeline;
  • the alkali leaching tank is connected to the water washing tank, and the drain outlet of the water washing tank is connected to the water washing liquid recovery tank through a pipeline;
  • the above system further includes a second filter press, the discharge port of the water washing tank is connected to the feed port of the second filter press, the discharge port of the second filter press is opposite to the second acid leaching tank, and the discharge port below the second filter press is connected to the water washing liquid recovery tank through a pipeline;
  • the second acid leaching tank is connected to the neutralization tank, the discharge port of the neutralization tank is opposite to the rare earth chloride product tank; the discharge port of the neutralization tank is opposite to the thorium-containing slag pool;
  • the first acid leaching tank, the alkali leaching tank, the water washing tank, the second acid leaching tank and the neutralization tank are independently provided with a pH online monitoring device and a temperature control device;
  • the suspended preheating decomposition furnace, the mineral phase converter and the electrostatic precipitator are independently provided with temperature measuring devices and pressure sensing devices for monitoring the operating temperature and pressure.
  • the method for using the system for mixed rare earth concentrate suspension phase conversion-clean leaching of the present invention is carried out according to the following steps:
  • the induced draft fan is started to generate negative pressure in the tail gas absorption station, the electrostatic precipitator, the venturi dryer, the first cyclone separator, the second cyclone separator, the suspension preheating decomposition furnace, and the third cyclone separator; the combustion flue gas is introduced into the venturi dryer to remove the adsorbed water of the mixed rare earth concentrate powder and to preheat the mixed rare earth concentrate powder;
  • the mixed rare earth concentrate powder in the feed bin is transported to the feed belt through a screw feeder; then transported to the Venturi dryer, after drying and dehydration, the mixed rare earth concentrate powder preheated to 150-200°C is sent to the first cyclone separator, and after cyclone separation, the bottom material is sent to the suspension preheating decomposition furnace through the second cyclone separator;
  • the burner generates flue gas by burning the mixed gas of air and reducing gas introduced into it.
  • the flue gas is introduced into the suspension preheating decomposition furnace through the air inlet at the bottom.
  • the materials entering the suspension preheating decomposition furnace are preheated and decomposed and are in a suspended state.
  • the material temperature is controlled at 550-800°C and the residence time is 1-10 minutes to obtain the suspended preheated decomposed materials.
  • the material after suspension preheating and decomposition enters the third cyclone separator. After cyclone separation, the bottom material first enters the first fluidized sealing valve to isolate oxygen and air, and then enters the mineral phase converter. Nitrogen is introduced into the mineral phase converter as a protective gas. Under the action of the protective gas, the material remains in a suspended state and completes the mineral phase conversion.
  • the material temperature is controlled at 450-650°C, and the residence time is 1-2.5h to obtain the material after mineral phase conversion.
  • the material is discharged through the second fluidized sealing valve, and then the mineral phase conversion product is discharged into the water cooling tank through the fifth cyclone separator and the sixth cyclone separator for water cooling, and finally passed into the ball mill;
  • the temperature of the material discharged into the water cooling tank is below 200°C.
  • the material is ground in a ball mill and then discharged into a spiral classifier, with the particle size of the material controlled to be -45 ⁇ m and the content accounting for 85-95 wt%, and then discharged into the first acid leaching tank;
  • the hydrochloric acid concentration used is 8-13 mol/L
  • the mass ratio of REO in the mixed rare earth concentrate powder to hydrochloric acid is 1:(1-3)
  • the leaching temperature is 65-100°C
  • the leaching time is 1-3h
  • the leached residue is passed into the first filter press for filtration to obtain acid leaching residue and corresponding leaching acid solution
  • the leaching acid solution is passed into the second acid leaching tank;
  • the acid leaching residue is passed into an alkaline leaching tank for NaOH alkaline decomposition, the mass concentration of NaOH is 50% to 80%, and the mass ratio of REO:NaOH in the acid leaching residue is 1:(0.5 to 2.5), the temperature is 130 to 220°C, and the time is 1 to 2 hours; the alkaline decomposition residue is discharged into a water washing tank for water washing, the water washing temperature is 55 to 100°C, and the water washing end point pH is 7 to 9;
  • the filter residue is mixed with the introduced leaching acid in the second acid leaching tank and then stirred for acid leaching.
  • the acid leaching temperature is 40-80° C.
  • the mass ratio of the filter residue to the leaching acid is 1:(5-10)
  • the time is 1-3 hours to obtain a leaching product;
  • the mixed rare earth concentrate powder preheated to 150-200°C is passed into the first cyclone separator, the separated dust is passed into the electrostatic precipitator, the flue gas after dust removal is passed into the electrostatic precipitator for purification, and then discharged from the chimney;
  • the dust collected by the electrostatic precipitator is returned to the third cyclone separator via the air lift pump under the action of the dust return fan;
  • the flue gas generated during the operation of the suspension preheating decomposition furnace is returned to the Venturi dryer via the third cyclone separator and the second cyclone separator to realize waste heat utilization;
  • the dust and gas separated by the fifth cyclone separator are returned to the third cyclone separator;
  • the dust and gas separated by the sixth cyclone separator are returned to the fifth cyclone separator, and the excess dust particles separated by the fifth cyclone separator enter the second ash hopper when passing through the pipeline.
  • the spiral classifier classifies the ground material and then returns the sand to the ball mill for further grinding;
  • the fuel in the burner is controlled to be fully burned, and the mineral phase conversion process in the suspension preheating decomposition furnace is kept in an oxygen-free or low-oxygen environment to achieve the directional conversion of CeCO 3 F to CeOF and prevent the generation of Ce(IV).
  • the main reactions are: CeCO 3 F ⁇ CeOF+CO 2 2CeCO 3 F ⁇ 2Ce 2 O 3 F 2 +2CO 2
  • the present invention provides a system for suspended phase transformation-clean leaching of mixed rare earth concentrate and a method for using the system.
  • the suspended phase transformation system provided by the present invention can provide higher heat and mass transfer efficiency, make the mineral powder particles undergo phase change in the fluidized system, and can realize the directional transformation of CeCO 3 F to CeOF at low temperature (450-650° C.) and in a short time, thereby avoiding oxidation of Ce(III) in the rare earth to Ce(VI) and generation of HF gas, and preventing the interference of F in the leachate while improving the rare earth leaching rate.
  • the addition of reducing agent in the hydrochloric acid leaching process can be reduced, thereby saving the cost of reagents.
  • the whole process of phase transformation and leaching in the system realizes the utilization of waste heat and the recovery and treatment of separated substances, and no gas containing fluorine, chlorine, sulfur, etc. is discharged, thereby eliminating waste gas pollution and reducing the pressure on environmental protection.
  • the system of the present invention can achieve low-temperature phase transformation of rare earth minerals, with the lowest transformation temperature reaching 450°C, and the mineral phase after transformation is CeOF.
  • FIG1 is a schematic diagram of the structure of a system for mixed rare earth concentrate suspension phase conversion-clean leaching according to the present invention
  • FIG2 is a schematic diagram of a mineral phase converter device of a system for suspended mineral phase conversion-clean leaching of a mixed rare earth concentrate according to the present invention
  • 11-1 mineral phase conversion feed port, 11-2. mineral phase conversion stop valve, 11-3. mineral phase conversion discharge port, 11-4. reduction chamber, 11-5. mineral phase conversion air distribution plate, 11-6. top baffle, 11-7. first bottom baffle, 11-8. mineral phase conversion air inlet, 11-9. air inlet stop valve, 11-10. second bottom baffle;
  • FIG3 is a schematic diagram of a fluidized sealing valve device of a system for mixed rare earth concentrate suspension phase conversion-clean leaching according to the present invention
  • 10-1 feed inlet, 10-2. discharge outlet, 10-3. top fluidizing sealing baffle, 10-4. fluidizing chamber, 10-5. fluidizing sealing air distribution plate, 10-6. bottom fluidizing sealing baffle, 10-7. nitrogen inlet stop valve, 10-8. nitrogen inlet.
  • the rare earth grade REO in the mixed rare earth concentrate selected in the embodiment of the present invention is 52-67%, and the iron grade TFe is 5-13%;
  • the water washing liquid in the embodiment of the present invention can be used to recover the alkali solution and the fluorine and phosphorus components after the recycling treatment;
  • the thorium-containing slag can be sealed or the thorium element can be further recovered;
  • FIG1 The structure diagram of a mixed rare earth concentrate suspended phase conversion-clean leaching system of the present invention is shown in FIG1 , comprising a feed bin 1, a screw feeder 2, a feed belt 3, a venturi dryer 4, a first cyclone separator 5, a second cyclone separator 6, a suspended preheating decomposition furnace 7, a third cyclone separator 9, a first fluidized sealing valve 10, a phase converter 11, a fourth cyclone separator 12, a second fluidized sealing valve 13, a fifth cyclone separator 14, a sixth cyclone separator 15, a water cooling tank 16, a ball mill 17, a first acid leaching tank 19, an alkali leaching tank 21, a water washing tank 22, a second acid leaching tank 25 and a neutralization tank 26;
  • the discharge port of the feeding bin 1 is opposite to the feed port of the screw feeder 2, and the discharge port of the screw feeder 2 is opposite to the feeding belt 3.
  • the discharge end of the feeding belt 3 is opposite to the feeding port of the venturi dryer 4
  • the top discharge port of the venturi dryer 4 is connected to the feeding port of the first cyclone separator 5 through a pipeline
  • the bottom discharge port of the first cyclone separator 5 is connected to the second cyclone separator 6
  • the bottom discharge port of the second cyclone separator 6 is connected to the suspension preheating decomposition furnace 7
  • the bottom of the suspension preheating decomposition furnace 7 is provided with a main burner 8 and connected to H 2
  • the top discharge port of the suspended preheating decomposition furnace 7 is connected with the feed port of the third cyclone separator 9 through a pipeline
  • the bottom discharge port of the third cyclone separator 9 is connected with the first fluidizing sealing valve 10
  • the first fluidizing sealing valve 10 is matched with the mineral phase converter 11
  • the discharge port of the ball mill 17 is connected to the feeding port of the spiral classifier 18
  • the overflow port of the spiral classifier 18 is connected to the feeding port of the first acid leaching tank 19 through a pipeline
  • the sand return port of the spiral classifier 18 is connected to the ball mill 17
  • the first acid leaching tank 19 and the discharge port are opposite to the first filter press 20
  • the discharge port of the first filter press 20 is connected to the alkali leaching tank 21
  • the alkali leaching tank 21 is connected to the water washing tank 22
  • the water washing tank 22 is connected to the feeding port of the second filter press 23
  • the discharge port of the second filter press 23 is opposite to the second acid leaching tank 25
  • the second acid leaching tank 25 is connected to the neutralization tank 26.
  • the top of the first cyclone separator 5 is connected to the electrostatic precipitator 29 through a pipeline, the electrostatic precipitator 29 is connected to the electrostatic precipitator 30, the electrostatic precipitator 30 cooperates with the induced draft fan 31, and the induced draft fan 31 is connected to the chimney 32 through a pipeline;
  • the discharge port of the electrostatic precipitator 29 is connected to the feed port of the air lift pump 33, the air lift pump 33 is connected to the ash return fan 34, and the discharge port of the air lift pump 33 is connected to the third cyclone separator 9 through a pipeline;
  • the top discharge port of the sixth cyclone separator 15 is connected to the fifth cyclone separator 14 through a pipeline, the top discharge port of the fifth cyclone separator 14 is connected to the third cyclone separator 9 through a pipeline, the top discharge port of the third cyclone separator 9 is connected to the second cyclone separator 6 through a pipeline, and the top discharge port of the second cyclone separator 6 is connected to the venturi dryer 4 through a pipeline;
  • a drying heat generator 37 is provided on the pipeline connecting the second cyclone separator 6 and the venturi dryer 4, and the drying heat generator 37 is connected to the H2/CO gas source through a pipeline, and the pipeline is also provided with a first ash hopper 35;
  • a second ash hopper 36 is provided on the connecting pipe between the fifth cyclone separator 14 and the sixth cyclone separator 15, for preventing some dust and particles from clogging the pipe during the material transfer process and for storing excess dust particles discharged from the pipe;
  • An air inlet is provided at the bottom of the mineral phase converter 11 and is connected to the nitrogen gas source pipeline.
  • a ventilation port is provided at the top of the mineral phase converter 11 and is connected to the fourth cyclone separator 12.
  • the bottom outlet of the fourth cyclone separator 12 is connected to the mineral phase converter 11, and the top outlet of the fourth cyclone separator 12 is connected to the suspended preheating decomposition furnace 7.
  • the first acid leaching tank 19 discharge port is connected to the second acid leaching tank 25 through a pipeline;
  • the drain outlet below the first filter press 20 is connected to the second acid leaching tank 25 through a pipeline;
  • the liquid discharge port of the washing tank 22 is connected to the washing liquid recovery tank 24 through a pipeline;
  • the lower drain port of the second filter press 23 is connected to the water washing liquid recovery tank 24 through a pipeline;
  • the discharge port of the neutralization tank 26 is opposite to the rare earth chloride product tank 27;
  • the discharge port of the neutralization tank 26 is opposite to the thorium-containing slag pool 28;
  • the first acid leaching tank 19, the alkali leaching tank 21, the water washing tank 22, the second acid leaching tank 25 and the neutralization tank 26 are provided with a pH online monitoring device and a temperature control device;
  • the suspended preheating decomposition furnace, mineral phase converter and dust removal device are all equipped with temperature measuring devices and pressure sensing devices to monitor the operating temperature and pressure.
  • the mineral phase converter 11 whose structural schematic diagram is shown in FIG2, mainly functions to provide a fluidized reduction chamber for mineral powder to achieve efficient mineral phase conversion.
  • Its main body includes a mineral phase converter shell, forming a reduction chamber 11-4, and a mineral phase conversion feed port 11-1 and a mineral phase conversion discharge port 11-3 are provided on the shell, and a mineral phase conversion stop valve 11-2 is provided on the pipeline where the mineral phase conversion feed port 11-1 is provided, and a plurality of top baffles 11-6 are arranged at intervals on the inner side of the shell located above, and a plurality of second bottom baffles 11-10 are arranged alternately on the inner side of the shell located below, and a first bottom baffle 11-7 is arranged directly below the top baffle 11-6, and a gap is left between the first bottom baffle 11-7 and the corresponding top baffle 11-6, and the top baffle 11-6 and the first bottom baffle 11-6 are arranged at intervals.
  • the baffle 11-7 and the second bottom baffle 11-10 together constitute a mineral powder flow channel, and the space formed between the top baffle 11-6 and the second bottom baffle 11-10 is a vertical channel; a mineral phase conversion air distribution plate 11-5 is provided on the shell on one side of the first bottom baffle 11-7 and the second bottom baffle 11-10 to evenly distribute the airflow; a mineral phase conversion air inlet 11-8 is provided in each vertical channel, and an air inlet stop valve 11-9 is provided on the pipeline provided with the mineral phase conversion air inlet 11-8, and the mineral phase conversion air inlet 11-8 is used to provide loosening air and fluidizing air required for the stable flow of mineral powder.
  • the structural schematic diagram of the first fluidized sealing valve 10 and the second fluidized sealing valve 13 is shown in Figure 3, and the main function is to isolate the gas introduced with the mineral powder in the previous stage.
  • Its main body includes a fluidized sealing shell, on which a feed port 10-1 and a discharge port 10-2 are arranged, and the fluidized sealing shell forms a fluidized chamber 10-4, a top fluidized sealing baffle 10-3 is arranged above the fluidized chamber, a bottom fluidized sealing baffle 10-6 is arranged below the fluidized chamber, and a fluidized sealing air distribution plate 10-5 is arranged on one side of the bottom fluidized sealing baffle 10-6 for evenly distributing the airflow; a nitrogen inlet 10-8 is arranged in each vertical channel, and a nitrogen inlet stop valve 10-7 is arranged on the pipeline where the nitrogen inlet 10-8 is arranged, and the nitrogen inlet 10-8 is used to provide loosening air and fluidizing air required for the stable flow of mineral powder.
  • a mixed rare earth concentrate suspended phase conversion-clean leaching method of the present invention adopts the above system and is carried out according to the following steps:
  • the mixed rare earth concentrate powder in the feeding bin 1 is transported to the feeding belt 3 through the screw feeder 2; the ore powder is transported to the feeding belt 3 through the screw feeder 2; The material is transported to the venturi dryer 4, and after drying and dehydration, it is sent to the first cyclone separator 5. After cyclone separation, the bottom material is sent to the suspension preheating decomposition furnace 7 through the second cyclone separator 6;
  • the top material separated by the first cyclone separator 5 is passed into the electrostatic precipitator 29, and the flue gas after dedusting is passed into the electrostatic precipitator 30 for purification and then discharged from the chimney 32;
  • the dust collected by the electrostatic precipitator 29 is returned to the third cyclone separator 9 via the air lift pump 33 under the action of the dust return fan 34;
  • the burner 8 generates flue gas by burning the air and coal gas introduced, and the flue gas is introduced through the air inlet at the bottom of the suspension preheating decomposition furnace 7, so that the material in the suspension preheating decomposition furnace 7 is preheated and decomposed and is in a suspended state.
  • a sufficient amount of coal gas is introduced into the suspension preheating decomposition furnace for combustion, and the entire mineral phase conversion process is carried out in an oxygen-free or low-oxygen environment to achieve the directional conversion of CeCO 3 F into CeOF and prevent the generation of Ce(IV); the material temperature is controlled at 600°C and the residence time is 5 minutes to obtain the suspended preheated decomposition material; the flue gas generated during the operation of the suspension preheating decomposition furnace 7 is returned to the Venturi dryer 4 via the third cyclone separator 9 and the second cyclone separator 6 to realize the waste heat utilization;
  • the material after suspension preheating and decomposition enters the third cyclone separator 9.
  • the bottom material first enters the first fluidized sealing valve 10 to isolate oxygen and air, and then enters the mineral phase converter 11. Nitrogen is introduced into the mineral phase converter 11 as a protective gas. Under the action of the protective gas, the material remains in a suspended state and completes the mineral phase conversion.
  • the material temperature is controlled at 470°C and the residence time is 1.5 hours.
  • the mineral phase conversion product is discharged through the second fluidized sealing valve 13, and then the product is cooled to below 200°C through the fifth cyclone separator 14 and the sixth cyclone separator 15 and discharged into the water cooling tank 16 for water cooling, and finally passed into the ball mill 17; the dust and gas separated by the fifth cyclone separator 14 are returned to the third cyclone separator 9; the dust and gas separated by the sixth cyclone separator 15 are returned to the fifth cyclone separator 14, and the excess dust particles separated by the fifth cyclone separator 14 enter the second ash hopper 36 when passing through the pipeline.
  • the material is ground in the ball mill 17 and then discharged into the spiral classifier 18.
  • the particle size of the material is controlled to be -45 ⁇ m and the content is 90%.
  • the returned sand is returned to the ball mill 17 for further grinding, and the overflow is discharged into the first acid leaching tank 19;
  • the first acid leaching tank 19 is used for hydrochloric acid leaching, the concentration of the hydrochloric acid used is 10 mol/L, the mass ratio of REO in the concentrate to hydrochloric acid is 1:2, the leaching temperature is 85°C, and the leaching time is 2.5 hours; the leached residue is passed into the first filter press 20 for pressure filtration, and the leachate is passed into the second acid leaching tank 25;
  • the alkali decomposition residue after washing is passed into the second filter press 23 for pressure filtration, the filtrate is passed into the washing liquid recovery tank 24, and the filter residue is passed into the second acid leaching tank 25;
  • the filter residue is mixed with the introduced acid leaching solution in the second acid leaching tank 25 and then stirred for acid leaching.
  • the acid leaching temperature is 65° C.
  • the mass ratio of the filter residue to the leaching acid is 1:8, and the time is 2 hours.
  • the rare earth chloride solution obtained after neutralization and impurity removal has a REO content of 242g/L, and a rare earth recovery rate of 94.81%.
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 600° C. and the residence time is 8 min;
  • the hydrochloric acid concentration used is 9 mol/L
  • the leaching temperature is 70°C
  • the leaching time is 2 h;
  • the NaOH concentration is 65%
  • the acid leaching temperature is 60°C
  • the mass ratio of filter residue to leaching acid is 1:7
  • the time is 3 hours
  • the NaOH concentration was 25%
  • the stirring time was 1 h
  • the endpoint pH was 5.
  • the REO content of the rare earth chloride solution obtained after neutralization and impurity removal was 226 g/L, and the rare earth recovery rate was 96.25%.
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 700° C. and the residence time is 10 min;
  • the hydrochloric acid concentration used is 11 mol/L
  • the leaching temperature is 75°C
  • the leaching time is 1 h;
  • the NaOH concentration is 70%
  • the temperature is 150°C
  • the time is 1h
  • the acid leaching temperature is 65°C
  • the mass ratio of filter residue to leaching acid is 1:7.5
  • the time is 2 h
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 750° C. and the residence time is 6 min;
  • the hydrochloric acid concentration used was 13 mol/L
  • the leaching temperature was 90°C
  • the leaching time was 1.5 h;
  • the NaOH concentration is 50%
  • the temperature is 160°C
  • the time is 1h
  • the acid leaching temperature is 70°C
  • the mass ratio of filter residue to leaching acid is 1:8, and the time is 2.5 h;
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 700° C. and the residence time is 7 min;
  • the hydrochloric acid concentration used is 12 mol/L
  • the leaching temperature is 80°C
  • the leaching time is 2 h;
  • the NaOH concentration is 60%
  • the acid leaching temperature is 65°C
  • the mass ratio of filter residue to leaching acid is 1:8, and the time is 2 h;
  • the NaOH concentration was 25%
  • the stirring time was 1.5 h
  • the endpoint pH was 4.
  • the REO content of the rare earth chloride solution obtained after neutralization and impurity removal was 252 g/L, and the rare earth recovery rate was 94.57%.
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 650° C. and the residence time is 8 min;
  • the hydrochloric acid concentration used is 12 mol/L
  • the leaching temperature is 85°C
  • the leaching time is 2 h;
  • the NaOH concentration is 55%
  • the acid leaching temperature is 60°C
  • the mass ratio of filter residue to leaching acid is 1:7
  • the time is 3 hours
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 700° C. and the residence time is 7 min;
  • hydrochloric acid concentration used was 11 mol/L
  • the leaching temperature was 85°C
  • the leaching time was 1.5 h;
  • the NaOH concentration is 65%
  • the temperature is 170°C
  • the time is 2h
  • the acid leaching temperature is 70°C
  • the mass ratio of filter residue to leaching acid is 1:7
  • the time is 2h
  • the NaOH concentration was 25%
  • the stirring time was 1.5 h
  • the endpoint pH was 4.
  • the REO content of the rare earth chloride solution obtained after neutralization and impurity removal was 229 g/L, and the rare earth recovery rate was 95.89%.
  • the system structure is the same as that of Example 1;
  • the material temperature in the suspension preheating decomposition furnace 7 is controlled at 600° C. and the residence time is 8 min;
  • the concentration of hydrochloric acid used is 10 mol/L
  • the leaching temperature is 75°C
  • the leaching time is 2 h;
  • the NaOH concentration is 60%
  • the temperature is 150°C
  • the time is 1.5 h;
  • the acid leaching temperature is 65°C
  • the mass ratio of filter residue to leaching acid is 1:7
  • the time is 2 h

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Abstract

一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法，属于选冶领域及资源综合回收领域。该系统包括文丘里干燥器（4）、多级分离器、悬浮预热分解炉（7）、多级流化密封阀、矿相转化器（11）、球磨机（17）、多级酸浸槽、碱浸槽（21）和中和槽（26），其使用方法为：将混合稀土精矿粉预热后，置于悬浮预热分解炉（7）中预热分解并处于悬浮状态，经旋风分离后进入矿相转化器（11）进行矿相转化，球磨后，进行酸洗、酸浸渣进行碱分解，酸液进行二次酸浸，浸出产物中和后，得到中和渣。该系统能够实现稀土矿物低温定相转化，避免矿相转化产物中四价铈的生成，提高稀土浸出率，还可同时防止生成氟、氯废气。

Description

混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法 技术领域
本发明涉及选冶领域及资源综合回收领域，具体为一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法。
背景技术
白云鄂博型混合稀土矿是我国内蒙古白云鄂博地区特有的一种铁-稀土-铌共生的稀土矿物，主要稀土成分为氟碳铈矿与独居石。其具有储量大、伴生矿石种类复杂、稀土含量高等特点；由于稀土矿物与大量赤、褐铁矿伴生且选矿性质相近，共生关系较为密切，因此导致常规选矿手段难以获得高品位的稀土精矿。
现阶段处理白云鄂博型混合稀土矿的主要手段为浓硫酸焙烧工艺，其优点为对稀土给料品位要求低，工艺相对简单，作业流程短，有利于大规模生产；但该方法的主要缺陷也较为明显：废水、废气及固体废弃物污染周边环境、由高温焙烧产生的焦磷酸钍难以回收利用，必须封存，不但占用大量土地，还给周边环境带来隐患；处理该类白云鄂博型混合稀土矿的另一种方法为碱分解法，相比于浓硫酸分解法，其生产方式较为清洁，资源综合回收效率较高；但也存在着对精矿品位要求高、作业流程不连续、浸出效率低、碱消耗量大、设备腐蚀严重等问题，难以工业化应用。
专利CN111926181A公开了一种分布回收稀土精矿中有价组分的方法，对混合稀土精矿采用流态化空气焙烧后进行盐酸优溶，得到少铈氯化稀土溶液与含钍富铈渣，富铈渣通过碱液分解后得以对F、P及铈钍进一步回收，该方法实现了对混合稀土精矿中有价元素的综合回收，但氟碳铈矿经氧化焙烧后在盐酸浸出过程中Ce4+会被Cl-还原成Ce3+并产生氯气，需要额外加入还原剂进行消除；并且浸出过程中部分F会与Ce4+以络合物形式分散于浸出液中，给萃取分离工序增加难度，减少经济效益。
专利CN109136590A公开了一种包头混合型稀土精矿分解处理工艺，该工艺采用了稀盐酸分级逆流优溶浸出的方法处理经氧化焙烧后的混合稀土精矿，得到低酸度的少铈氯化稀土溶液及盐酸优浸渣，避免了氧化焙烧后氟碳铈矿在盐酸浸出过程中Ce4+与F的配位浸出；但该工艺存在浸出工序较为复杂、浸出速度较为缓慢等不足。
发明内容
针对上述现有技术存在的问题，本发明提供一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法，能够实现稀土矿物低温定相转化，避免矿相转化产物中四价铈的生成， 提高稀土浸出率，还可同时防止生成氟、氯废气。
本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统，包括：
给料仓、文丘里干燥器、第一旋风分离器、第二旋风分离器、悬浮预热分解炉、第三旋风分离器、第一流化密封阀、矿相转化器、第二流化密封阀、第五旋风分离器、水冷槽、球磨机、第一酸浸槽、碱浸槽、水洗槽、第二酸浸槽、中和槽；
其中，给料仓和与文丘里干燥器相连通，文丘里干燥器的顶端出料口通过管道与第一旋风分离器的进料口相连通，第一旋风分离器底部出料口与第二旋风分离器连通，第二旋风分离器底部出料口与悬浮预热分解炉连通，悬浮预热分解炉的顶部出料口通过管道与第三旋风分离器的入料口连通，第三旋风分离器的底部出料口与第一流化密封阀连通，第一流化密封阀与矿相转化器相配合，矿相转化器的出料口与第二流化密封阀连通，第二流化密封阀出料口与第五旋风分离器的入料口相连通，第五旋风分离器的底部出料口与水冷槽相对，水冷槽与球磨机相对，球磨机排料口与第一酸浸槽入料口连通，第一酸浸槽与出料口与碱浸槽连通，碱浸槽与水洗槽连通，水洗槽与第二酸浸槽相对，第二酸浸槽与中和槽连通。
上述系统中，还包括螺旋给料机和送料皮带，给料仓的出料口与螺旋给料机的进料口相对，螺旋给料机的出料口与送料皮带相对，送料皮带的出料端与文丘里干燥器的入料口相对。
上述系统中，悬浮预热分解炉的底部设有主燃烧器，主燃烧器并通过管道与还原气气源及空气气源连通。所述的还原气选用H2和/或CO。
上述系统中，第一旋风分离器顶部通过管道与电除尘器连通，电除尘器与尾气吸收站连通，尾气吸收站和引风机相配合，引风机通过管道与烟囱连通；
上述系统中，电除尘器排料口与气力提升泵进料口连通，气力提升泵与返灰风机连通，气力提升泵出料口通过管道与第三旋风分离器连通；
上述系统中，还设置有第六旋风分离器、第五旋风分离器底部出料口通过管道和第六旋风分离器连通，并在连通管道上设置有第二灰斗，第六旋风分离器顶部出料口通过管道与第五旋风分离器连通，第五旋风分离器顶部出料口通过管道与第三旋风分离器连通，第三旋风分离器顶部出料口通过管道与第二旋风分离器连通，第二旋风分离器顶部出料口通过管道与文丘里干燥器连通；并在连通管道上设置有干燥热发生器和第一灰斗，其中，干燥热发生器通过管道与还原气气源相连通，还原气气源选用H2和/或CO；
上述系统中，第一流化密封阀与第二流化密封阀底部均设有进气口并与氮气气源管道连通；
上述系统中，矿相转化器底部设有进气口并与氮气气源管道相连通，矿相转化器顶部设有换气口并与第四旋风分离器连通；第四旋风分离器的底部出料口和矿相转化器连通，第四 旋风分离器的顶部出料口和悬浮预热分解炉连通。
所述的矿相转化器的主要作用是为矿粉提供流态化还原腔室以实现高效矿相转化。其主体包括矿相转化器壳体，形成还原室，壳体上设置有矿相转化进料口和矿相转化出料口，在位于上方的壳体内侧间隔设置多个顶部挡板，在位于下方的壳体内侧交错设置多个第二底部挡板，并在顶部挡板的正下方设置有第一底部挡板，第一底部挡板和对应的顶部挡板之间留有空隙，顶部挡板和第一底部挡板和第二底部挡板共同构成矿粉流动通道，顶部挡板和第二底部挡板之间形成的空间为垂直通道；在设置第一底部挡板和第二底部挡板一侧的壳体上设置有矿相转化布风板，用以平均分布气流；在每个垂直通道内设置均设置有矿相转化进气口，用以提供矿粉稳定流动所需的松动风及流化风。
所述的第一流化密封阀和第二流化密封阀的主要作用是隔绝上一阶段随矿粉通入的气体。其主体包括流化密封壳体，流化密封壳体形成流化室，流化室上方设置有顶部流化密封挡板，在顶部流化密封挡板正下方设置有底部流化密封挡板，并在底部流化密封挡板一侧设置有流化密封布风板，用于平均分布气流；在每个垂直通道内设置有氮气进气口，用以提供矿粉稳定流动所需的松动风及流化风。
上述系统中，球磨机排料口与螺旋分级机给料口连通，螺旋分级机溢流口通过管道与第一酸浸槽入料口连通，螺旋分级机返砂口与球磨机连通。
上述系统中，第一酸浸槽排液口通过管道与第二酸浸槽连通；
上述系统中，还包括第一压滤机，第一酸浸槽的出料口与第一压滤机相对，第一压滤机排料口与碱浸槽连通，第一压滤机下方排液口通过管道与第二酸浸槽连通；
上述系统中，碱浸槽和水洗槽连通，水洗槽排液口通过管道与水洗液回收槽连通；
上述系统中，还包括第二压滤机，水洗槽的出料口与第二压滤机入料口连通，第二压滤机排料口与第二酸浸槽相对，第二压滤机下方排液口通过管道与水洗液回收槽连通；
上述系统中，第二酸浸槽和中和槽连通，中和槽排液口与氯化稀土产品槽相对；中和槽排料口与含钍渣池相对；
上述系统中，第一酸浸槽、碱浸槽、水洗槽、第二酸浸槽及中和槽均独立设有pH在线监测装置及温控装置；
上述系统中，悬浮预热分解炉、矿相转化器及电除尘器均独立设有测温装置及压力传感装置，用于监测作业温度及压力。
本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统的使用方法，按以下步骤进行：
S1、准备
启动引风机，使尾气吸收站、电除尘器、文丘里干燥器、第一旋风分离器、第二旋风分离器、悬浮预热分解炉、第三旋风分离器内产生负压；文丘里干燥器内通入燃烧烟气，用以脱除混合稀土精矿粉吸附水并对混合稀土精矿粉进行预热；
S2、干燥分离
将给料仓内混合稀土精矿粉通过螺旋送料机运送至送料皮带；再运送到文丘里干燥器内，经干燥脱水后，预热至150～200℃的混合稀土精矿粉送入第一旋风分离器内，经旋风分离后，底部物料经由第二旋风分离器送入悬浮预热分解炉内；
S3、悬浮预热分解
燃烧器内通过燃烧通入的空气及还原气混合气体产生烟气，烟气经由悬浮预热分解炉底部的进气口通入，进入悬浮预热分解炉内的物料预热分解并处于悬浮状态，控制物料温度在550～800℃，停留时间1～10min，得到悬浮预热分解后的物料；
S4、矿相转化
完成悬浮预热分解后的物料进入第三旋风分离器内，经旋风分离后，底部物料首先进入第一流化密封阀中隔绝氧气及空气，随后物料进入矿相转化器中，矿相转化器通入氮气作为保护气，物料在保护气作用下保持悬浮状态并完成矿相转化，控制物料温度在450～650℃，停留时间1～2.5h，得到矿相转化后的物料；
S5、水冷
完成矿相转化后的物料经由第二流化密封阀将产物排出，随后矿相转化产物经由第五旋风分离器及第六旋风分离器排入水冷槽内进行水冷，最后通入球磨机中；
所述的排入水冷槽的物料温度为200℃以下。
S6、清洁浸出
(1)物料在球磨机内磨细后排入螺旋分级机中，控制物料粒度在-45μm含量占85～95wt％，随后排入第一酸浸槽；
(2)第一酸浸槽内进行盐酸浸出，所用盐酸浓度为8～13mol/L，按质量比，混合稀土精矿粉中REO︰盐酸＝1︰(1～3)，浸出温度为65～100℃，浸出时间为1～3h；浸出渣通入第一压滤机内进行压滤，得到酸浸渣和对应的浸出酸液，浸出酸液通入第二酸浸槽内；
(3)酸浸渣通入碱浸槽内进行NaOH碱分解，NaOH的质量浓度为50％～80％，按质量比，酸浸渣中REO︰NaOH＝1︰(0.5～2.5)，温度为130～220℃，时间为1～2h；碱分解渣排入水洗槽内进行水洗，水洗温度为55～100℃，水洗终点pH＝7～9；
(4)水洗后的碱分解渣通入第二压滤机内进行压滤，滤液通入水洗液回收槽内，滤渣通入第二酸浸槽；
(5)滤渣在第二酸浸槽内与通入的浸出酸液混合后共同搅拌酸浸，酸浸温度为40～80℃，按质量比，滤渣：浸出酸液为1︰(5～10)，时间为1～3h，得到浸出产物；
(6)浸出产物通入中和槽后，向中和槽内加入NaOH并持续搅拌混合，NaOH的质量浓度为15％～35％，搅拌时间1～2.5h，终点pH＝4～5；完成中和后，中和液通入氯化稀土产品槽内，中和渣通入含钍渣池。
上述系统的使用方法中，预热至150～200℃的混合稀土精矿粉通入第一旋风分离器后，分离出的粉尘通入电除尘器，除尘后的烟气通入电除尘器进行净化处理，随后由烟囱排出；
上述系统的使用方法中，电除尘器收集的粉尘在返灰风机的作用下经由气力提升泵返回第三旋风分离器内；
上述系统的使用方法中，悬浮预热分解炉运行过程中产生的烟气经由第三旋风分离器与第二旋风分离器返回文丘里干燥器以实现余热利用；
上述系统的使用方法中，第五旋风分离器分离出的粉尘及气体返回第三旋风分离器；
上述系统的使用方法中，第六旋风分离器分离出的粉尘及气体返回第五旋风分离器，第五旋风分离器分离出的多余粉尘颗粒在通过管道时进入第二灰斗。
上述系统的使用方法中，螺旋分级机对磨矿物料分级后返砂返回球磨机再磨；
上述系统的使用方法中，控制燃烧器内燃料充分燃烧，保持悬浮预热分解炉内的矿相转化过程在无氧或低氧环境下进行，以实现CeCO3F定向转化为CeOF，防止Ce(Ⅳ)的生成，主要反应为：
CeCO3F→CeOF+CO2
2CeCO3F→2Ce2O3F2+2CO2
本发明提供了一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法，与传统处理稀土精矿的氧化焙烧技术及装置相比，本发明提供的悬浮态矿相转化系统能提供更高的传热传质效率，使矿粉颗粒在流态化体系中发生相变，能够在低温(450～650℃)、短时间内实现CeCO3F向CeOF的定向转化，避免稀土中Ce(III)被氧化为Ce(VI)以及生成HF气体，在提高稀土浸出率的同时防止F在浸出液中的干扰，此外还可减免盐酸浸出过程中的还原剂添加，节省药剂成本；本系统中的矿相转化及浸出全流程实现了余热利用与分离物质回收处理，且无含氟、氯、硫等气体排放，消除了废气污染，减轻了环保压力。
并且相比于现有的稀土精矿焙烧技术相比，本发明的系统能够实现稀土矿物低温定相转化，转化温度最低可至450℃，转化后的矿相为CeOF。
附图说明
图1为本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统结构示意图；
图中，1.给料仓、2.螺旋给料机、3.送料皮带、4.文丘里干燥器、5.第一旋风分离器、6.第二旋风分离器、7.悬浮预热分解炉、8.主燃烧器、9.第三旋风分离器、10.第一流化密封阀、11.矿相转化器、12.第四旋风分离器、13.第二流化密封阀、14.第五旋风分离器、15.第六旋风分离器、16.水冷槽、17.球磨机、18.螺旋分级机、19.第一酸浸槽、20.第一压滤机、21.碱浸槽、22.水洗槽、23.第二压滤机、24.水洗液回收槽、25.第二酸浸槽、26.中和槽、27.氯化稀土产品槽、28.含钍渣池、29.电除尘器、30.尾气吸收站、31.引风机、32.烟囱、33.气力提升泵、34.返灰风机、35.第一灰斗、36.第二灰斗、37.干燥热发生器。
图2为本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统的矿相转化器装置示意图；
图中，11-1.矿相转化进料口、11-2.矿相转化截止阀、11-3.矿相转化出料口、11-4.还原室、11-5.矿相转化布风板、11-6.顶部挡板、11-7.第一底部挡板、11-8.矿相转化进气口、11-9.进气口截止阀、11-10.第二底部挡板；
图3为本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统的流化密封阀装置示意图；
图中，10-1.进料口、10-2.出料口、10-3.顶部流化密封挡板、10-4.流化室、10-5.流化密封布风板、10-6.底部流化密封挡板、10-7.氮气进气截止阀、10-8.氮气进气口。
具体实施方式
下面结合实施例对本发明作进一步的详细说明。
本发明实施例中选用的混合稀土精矿中稀土品位REO为52～67％，铁品位TFe为5～13％；
本发明实施例中水洗液经回收处理后可用于回收碱液及氟、磷组分；
本发明实施例中含钍渣可进行封存或对钍元素进行进一步回收；
以下结合附图以及实施例对本发明作进一步阐述。下述实施例中所述设备、试剂和材料，如无特殊说明，均可以从商业渠道获得；所述试验方法，如无特殊说明，均为常规方法。
实施例1
本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出系统结构图如图1所示，包括给料仓1、螺旋给料机2、送料皮带3、文丘里干燥器4、第一旋风分离器5、第二旋风分离器6、悬浮预热分解炉7、第三旋风分离器9、第一流化密封阀10、矿相转化器11、第四旋风分离器12、第二流化密封阀13、第五旋风分离器14、第六旋风分离器15、水冷槽16、球磨机17、第一酸浸槽19、碱浸槽21、水洗槽22、第二酸浸槽25和中和槽26；
给料仓1的出料口与螺旋给料机2的进料口相对，螺旋给料机2的出料口与送料皮带3 相对，送料皮带3的出料端与文丘里干燥器4的入料口相对，文丘里干燥器4的顶端出料口通过管道与第一旋风分离器5的进料口相连通，第一旋风分离器5底部出料口与第二旋风分离器6连通，第二旋风分离器6底部出料口与悬浮预热分解炉7连通，悬浮预热分解炉7的底部设有主燃烧器8并通过管道与H2/CO气气源及空气气源连通，悬浮预热分解炉7的顶部出料口通过管道与第三旋风分离器9的入料口连通，第三旋风分离器9的底部出料口与第一流化密封阀10连通，第一流化密封阀10与矿相转化器11相配合，矿相转化器11的出料口与第二流化密封阀13连通，第二流化密封阀13出料口与第五旋风分离器14的入料口相连通，第五旋风分离器14的底部出料口通过第六旋风分离器15后与水冷槽16相对，水冷槽16与球磨机17相对，球磨机17排料口与螺旋分级机18给料口连通，螺旋分级机18溢流口通过管道与第一酸浸槽19给料口连通，螺旋分级机18返砂口与球磨机17连通，第一酸浸槽19与出料口与第一压滤机20相对，第一压滤机20排料口与碱浸槽21连通，碱浸槽21与水洗槽22连通，水洗槽22与第二压滤机23入料口连通，第二压滤机23排料口与第二酸浸槽25相对，第二酸浸槽25与中和槽26连通。
第一旋风分离器5顶部通过管道与电除尘器29连通，电除尘器29与电除尘器30连通，电除尘器30和引风机31相配合，引风机31通过管道与烟囱32连通；
电除尘器29排料口与气力提升泵33进料口连通，气力提升泵33与返灰风机34连通，气力提升泵33出料口通过管道与第三旋风分离器9连通；
第六旋风分离器15顶部出料口通过管道与第五旋风分离器14连通，第五旋风分离器14顶部出料口通过管道与第三旋风分离器9连通，第三旋风分离器9顶部出料口通过管道与第二旋风分离器6连通，第二旋风分离器6顶部出料口通过管道与文丘里干燥器4连通；在第二旋风分离器6和文丘里干燥器4连通的管道上设置有干燥热发生器37，干燥热发生器37通过管道与H2/CO气源相连通，该管道上同时设有第一灰斗35；
在第五旋风分离器14与第六旋风分离器15之间的连接的管道上，设置有第二灰斗36，用于防止物料转移过程中部分粉尘及颗粒在管道内发生堵塞，用于储存管道内排出的多余粉尘颗粒；
矿相转化器11底部设有进气口并与氮气气源管道相连通，矿相转化器11顶部设有换气口并与第四旋风分离器12连通；第四旋风分离器12的底部出口和矿相转化器11连通，第四旋风分离器12的顶部出口和悬浮预热分解炉7连通。
第一酸浸槽19排液口通过管道与第二酸浸槽25连通；
第一压滤机20下方排液口通过管道与第二酸浸槽25连通；
水洗槽22排液口通过管道与水洗液回收槽24连通；
第二压滤机23下方排液口通过管道与水洗液回收槽24连通；
中和槽26排液口与氯化稀土产品槽27相对；
中和槽26排料口与含钍渣池28相对；
第一酸浸槽19、碱浸槽21、水洗槽22、第二酸浸槽25及中和槽26设有pH在线监测装置及温控装置；
悬浮预热分解炉、矿相转化器及除尘装置均设有测温装置及压力传感装置，用于监测作业温度及压力。
其中，所述的矿相转化器11其结构示意图见图2，的主要作用是为矿粉提供流态化还原腔室以实现高效矿相转化。其主体包括矿相转化器壳体，形成还原室11-4，壳体上设置有矿相转化进料口11-1和矿相转化出料口11-3，在设置矿相转化进料口11-1的管道上设置有矿相转化截止阀11-2，在位于上方的壳体内侧间隔设置多个顶部挡板11-6，在位于下方的壳体内侧交错设置多个第二底部挡板11-10，并在顶部挡板11-6的正下方设置有第一底部挡板11-7，第一底部挡板11-7和对应的顶部挡板11-6之间留有空隙，顶部挡板11-6和第一底部挡板11-7和第二底部挡板11-10共同构成矿粉流动通道，顶部挡板11-6和第二底部挡板11-10之间形成的空间为垂直通道；在设置第一底部挡板11-7和第二底部挡板11-10一侧的壳体上设置有矿相转化布风板11-5，用以平均分布气流；在每个垂直通道内设置均设置有矿相转化进气口11-8，并在设置有矿相转化进气口11-8的管道上设置有进气口截止阀11-9，矿相转化进气口11-8用以提供矿粉稳定流动所需的松动风及流化风。
所述的第一流化密封阀10和第二流化密封阀13的结构示意图见图3，主要作用是隔绝上一阶段随矿粉通入的气体。其主体包括流化密封壳体，流化密封壳体上设置有进料口10-1和出料口10-2，流化密封壳体形成流化室10-4，流化室上方设置有顶部流化密封挡板10-3，在流化室下方设置有底部流化密封挡板10-6，并在底部流化密封挡板10-6一侧设置有流化密封布风板10-5，用于平均分布气流；在每个垂直通道内设置有氮气进气口10-8，在设置氮气进气口10-8的管道上设置有氮气进气截止阀10-7，氮气进气口10-8用以提供矿粉稳定流动所需的松动风及流化风。
本发明的一种混合稀土精矿悬浮态矿相转化-清洁浸出方法采用上述系统，按以下步骤进行：
启动引风机31，使电除尘器29、尾气吸收站30、文丘里干燥器4、第一旋风分离器5、第二旋风分离器6、悬浮预热分解炉7、第三旋风分离器9内产生负压；文丘里干燥器4内通入燃烧烟气，用以脱除矿粉吸附水并对物料进行预热，出料口物料温度为150℃；
将给料仓1内混合稀土精矿粉通过螺旋送料机2运送至送料皮带3；矿粉通过送料皮带3 运送到文丘里干燥器4内，经干燥脱水后送入第一旋风分离器5内，经旋风分离后，底部物料经由第二旋风分离器6送入悬浮预热分解炉7内；
第一旋风分离器5分离的顶部物料通入电除尘器29，除尘后的烟气通入电除尘器30进行净化处理，随后由烟囱32排出；
电除尘器29收集的粉尘在返灰风机34的作用下经由气力提升泵33返回第三旋风分离器9内；
燃烧器8内通过燃烧通入的空气及煤制气产生烟气，烟气经由悬浮预热分解炉7底部的进气口通入，使悬浮预热分解炉7内的物料预热分解并处于悬浮状态，悬浮预热分解炉内通入足量煤制气进行燃烧，保持整个矿相转化过程在无氧或低氧环境下进行，以实现CeCO3F定向转化为CeOF，防止Ce(Ⅳ)的生成；控制物料温度在600℃，停留时间5min，得到悬浮预热分解后的物料；悬浮预热分解炉7运行过程中产生的烟气经由第三旋风分离器9与第二旋风分离器6返回文丘里干燥器4以实现余热利用；
完成悬浮预热分解后的物料进入第三旋风分离器9内，经旋风分离后，底部物料首先进入第一流化密封阀10中隔绝氧气及空气，随后物料进入矿相转化器11中，矿相转化器11内通入氮气作为保护气，物料在保护气作用下保持悬浮状态并完成矿相转化，控制物料温度在470℃，停留时间1.5h；
物料完成矿相转化后经由第二流化密封阀13将矿相转化产物排出，随后产物经由第五旋风分离器14及第六旋风分离器15降温至200℃以下排入水冷槽16内进行水冷，最后通入球磨机17中；第五旋风分离器14分离出的粉尘及气体返回第三旋风分离器9；第六旋风分离器15分离出的粉尘及气体返回第五旋风分离器14，第五旋风分离器14分离出的多余粉尘颗粒在通过管道时进入第二灰斗36。
物料在球磨机17内磨细后排入螺旋分级机18中，控制物料粒度在-45μm含量占90％，分级后返砂返回球磨机17再磨，溢流排入第一酸浸槽19；
第一酸浸槽19内进行盐酸浸出，所用盐酸浓度为10mol/L，按质量比，精矿中REO︰盐酸＝1︰2，浸出温度为85℃，浸出时间为2.5h；浸出渣通入第一压滤机20内进行压滤，浸出液通入第二酸浸槽25内；
固液分离后的酸浸渣通入碱浸槽21内进行NaOH碱分解，NaOH浓度为60％，NaOH用量为：按质量比，浸渣中REO︰NaOH＝1︰1，温度为180℃，时间为1.5h；碱分解渣排入水洗槽22内进行水洗，水洗温度为80℃，水洗终点pH＝8；
水洗后的碱分解渣通入第二压滤机23内进行压滤，滤液通入水洗液回收槽24内，滤渣通入第二酸浸槽25；
滤渣在第二酸浸槽25内与通入的酸浸液混合后共同搅拌酸浸，酸浸温度为65℃，按质量比，滤渣：浸出酸液为1︰8，时间为2h；
浸出液通入中和槽26后，向中和槽26内加入NaOH并持续搅拌混合，NaOH浓度为20％，搅拌时间1.5h，终点pH＝4；完成中和后，中和液通入氯化稀土产品槽27内，中和渣通入和含钍渣池28。浸液经中和除杂后获得的氯化稀土溶液REO含量为242g/L，稀土回收率为94.81％。
实施例2
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在600℃，停留时间8min；
(2)矿相转化器11中物料温度控制在550℃，停留时间1h；
(3)矿相转化产物磨至-45μm含量占92wt％；
(4)盐酸浸出作业中，所用盐酸浓度为9mol/L，盐酸用量为，按质量比，精矿中REO︰盐酸＝1︰3，浸出温度为70℃，浸出时间为2h；
(5)碱分解作业中，NaOH浓度为65％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰2.5，温度为170℃，时间为2h；
(6)水洗作业中，水洗温度为70℃，水洗终点pH＝8；
(7)混合酸浸作业中，酸浸温度为60℃，按质量比，滤渣：浸出酸液为1︰7，时间为3h；
(8)中和作业中，NaOH浓度为25％，搅拌时间1h，终点pH＝5；浸液经中和除杂后获得的氯化稀土溶液REO含量为226g/L，稀土回收率为96.25％。
实施例3
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在700℃，停留时间10min；
(2)矿相转化器11中物料温度控制在620℃，停留时间1.2h；
(3)矿相转化产物磨至-45μm含量占90wt％；
(4)盐酸浸出作业中，所用盐酸浓度为11mol/L，盐酸用量为，按质量比，精矿中REO︰盐酸＝1︰2.5，浸出温度为75℃，浸出时间为1h；
(5)碱分解作业中，NaOH浓度为70％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰2，温度为150℃，时间为1h；
(6)水洗作业中，水洗温度为55℃，水洗终点pH＝7.5；
(7)混合酸浸作业中，酸浸温度为65℃，按质量比，滤渣：浸出酸液为1︰7.5，时间为2h；
(8)中和作业中，NaOH浓度为20％，搅拌时间1.5h，终点pH＝4.5；浸液经中和除杂后获得的氯化稀土溶液REO含量为240g/L，稀土回收率为95.33％。
实施例4
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在750℃，停留时间6min；
(2)矿相转化器11中物料温度控制在550℃，停留时间1.5h；
(3)矿相转化产物磨至-45μm含量占90wt％；
(4)盐酸浸出作业中，所用盐酸浓度为13mol/L，盐酸用量为按质量比，精矿中REO︰盐酸＝1︰2，浸出温度为90℃，浸出时间为1.5h；
(5)碱分解作业中，NaOH浓度为50％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰1，温度为160℃，时间为1h；
(6)水洗作业中，水洗温度为60℃，水洗终点pH＝9；
(7)混合酸浸作业中，酸浸温度为70℃，按质量比，滤渣：浸出酸液为1︰8，时间为2.5h；
(8)中和作业中，NaOH浓度为15％，搅拌时间1.5h，终点pH＝5；浸液经中和除杂后获得的氯化稀土溶液REO含量为213g/L，稀土回收率为96.13％。
实施例5
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在700℃，停留时间7min；
(2)矿相转化器11中物料温度控制在500℃，停留时间1h；
(3)矿相转化产物磨至-45μm含量占95wt％；
(4)盐酸浸出作业中，所用盐酸浓度为12mol/L，盐酸用量为，按质量比，精矿中REO︰盐酸＝1︰2，浸出温度为80℃，浸出时间为2h；
(5)碱分解作业中，NaOH浓度为60％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰1.5，温度为160℃，时间为1.5h；
(6)水洗作业中，水洗温度为65℃，水洗终点pH＝8；
(7)混合酸浸作业中，酸浸温度为65℃，按质量比，滤渣：浸出酸液为1︰8，时间为2h；
(8)中和作业中，NaOH浓度为25％，搅拌时间1.5h，终点pH＝4；浸液经中和除杂后获得的氯化稀土溶液REO含量为252g/L，稀土回收率为94.57％。
实施例6
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在650℃，停留时间8min；
(2)矿相转化器11中物料温度控制在500℃，停留时间1h；
(3)矿相转化产物磨至-45μm含量占95wt％；
(4)盐酸浸出作业中，所用盐酸浓度为12mol/L，盐酸用量为，按质量比，精矿中REO︰盐酸＝1︰3，浸出温度为85℃，浸出时间为2h；
(5)碱分解作业中，NaOH浓度为55％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰1.5，温度为170℃，时间为1h；
(6)水洗作业中，水洗温度为70℃，水洗终点pH＝8；
(7)混合酸浸作业中，酸浸温度为60℃，按质量比，滤渣：浸出酸液为1︰7，时间为3h；
(8)中和作业中，NaOH浓度为20％，搅拌时间2h，终点pH＝4.5；浸液经中和除杂后获得的氯化稀土溶液REO含量为247g/L，稀土回收率为95.32％。
实施例7
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在700℃，停留时间7min；
(2)矿相转化器11中物料温度控制在450℃，停留时间2h；
(3)矿相转化产物磨至-45μm含量占92wt％；
(4)盐酸浸出作业中，所用盐酸浓度为11mol/L，盐酸用量为，按质量比，精矿中REO︰盐酸＝1︰2.5，浸出温度为85℃，浸出时间为1.5h；
(5)碱分解作业中，NaOH浓度为65％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰1，温度为170℃，时间为2h；
(6)水洗作业中，水洗温度为65℃，水洗终点pH＝7；
(7)混合酸浸作业中，酸浸温度为70℃，按质量比，滤渣：浸出酸液为1︰7，时间为 2h；
(8)中和作业中，NaOH浓度为25％，搅拌时间1.5h，终点pH＝4；浸液经中和除杂后获得的氯化稀土溶液REO含量为229g/L，稀土回收率为95.89％。
实施例8
系统结构同实施例1；
方法同实施例1，不同点在于：
(1)悬浮预热分解炉7内的物料温度控制在600℃，停留时间8min；
(2)矿相转化器11中物料温度控制在600℃，停留时间2.5h；
(3)矿相转化产物磨至-45μm含量占95wt％；
(4)盐酸浸出作业中，所用盐酸浓度为10mol/L，盐酸用量，按质量比，精矿中REO︰盐酸＝1︰2，浸出温度为75℃，浸出时间为2h；
(5)碱分解作业中，NaOH浓度为60％，NaOH用量为，按质量比，浸渣中REO︰NaOH＝1︰1，温度为150℃，时间为1.5h；
(6)水洗作业中，水洗温度为70℃，水洗终点pH＝8；
(7)混合酸浸作业中，酸浸温度为65℃，按质量比，滤渣：浸出酸液为1︰7，时间为2h；
(8)中和作业中，NaOH浓度为20％，搅拌时间1h，终点pH＝4.5；浸液经中和除杂后获得的氯化稀土溶液REO含量为222g/L，稀土回收率为95.66％。

Claims (10)

  1. 一种混合稀土精矿悬浮态矿相转化-清洁浸出的系统，其特征在于，该混合稀土精矿悬浮态矿相转化-清洁浸出的系统包括：
    给料仓(1)、文丘里干燥器(4)、第一旋风分离器(5)、第二旋风分离器(6)、悬浮预热分解炉(7)、第三旋风分离器(9)、第一流化密封阀(10)、矿相转化器(11)、第二流化密封阀(13)、第五旋风分离器(14)、水冷槽(16)、球磨机(17)、第一酸浸槽(19)、碱浸槽(21)、水洗槽(22)、第二酸浸槽(25)、中和槽(26)；
    其中，给料仓(1)和与文丘里干燥器(4)相连通，文丘里干燥器(4)的顶端出料口通过管道与第一旋风分离器(5)的进料口相连通，第一旋风分离器(5)底部出料口与第二旋风分离器(6)连通，第二旋风分离器(6)底部出料口与悬浮预热分解炉(7)连通，悬浮预热分解炉(7)的顶部出料口通过管道与第三旋风分离器(9)的入料口连通，第三旋风分离器(9)的底部出料口与第一流化密封阀(10)连通，第一流化密封阀(10)与矿相转化器(11)相配合，矿相转化器(11)的出料口与第二流化密封阀(13)连通，第二流化密封阀(13)出料口与第五旋风分离器(14)的入料口相连通，第五旋风分离器(14)的底部出料口与水冷槽(16)相对，水冷槽(16)与球磨机(17)相对，球磨机(17)排料口与第一酸浸槽(19)入料口连通，第一酸浸槽(19)与出料口与碱浸槽(21)连通，碱浸槽(21)与水洗槽(22)连通，水洗槽(22)与第二酸浸槽(25)相对，第二酸浸槽(25)与中和槽(26)连通。
  2. 根据权利要求1所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统，其特征在于，混合稀土精矿悬浮态矿相转化-清洁浸出的系统中，还包括螺旋给料机(2)和送料皮带(3)，给料仓(1)的出料口与螺旋给料机(2)的进料口相对，螺旋给料机(2)的出料口与送料皮带(3)相对，送料皮带(3)的出料端与文丘里干燥器(4)的入料口相对；
    和/或，悬浮预热分解炉(7)的底部设有主燃烧器(8)，主燃烧器(8)并通过管道与还原气气源及空气气源连通。
  3. 根据权利要求1所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统，其特征在于，第一旋风分离器(5)顶部通过管道与电除尘器(29)连通，电除尘器(29)与尾气吸收站(30)连通，尾气吸收站(30)和引风机(31)相配合，引风机(31)通过管道与烟囱(32)连通；
    电除尘器(29)排料口与气力提升泵(33)进料口连通，气力提升泵(33)与返灰风机(34)连通，气力提升泵(33)出料口通过管道与第三旋风分离器(9)连通；
    还设置有第六旋风分离器(15)、第五旋风分离器(14)底部出料口通过管道和第六旋风分离器(15)连通，并在连通管道上设置有第二灰斗(36)，第六旋风分离器(15)顶部出料口通过管道与第五旋风分离器(14)连通，第五旋风分离器(14)顶部出料口通过管道与第三旋风分离器(9)连通，第三旋风分离器(9)顶部出料口通过管道与第二旋风分离器(6) 连通，第二旋风分离器(6)顶部出料口通过管道与文丘里干燥器(4)连通；并在连通管道上设置有干燥热发生器(37)和第一灰斗(35)，其中，干燥热发生器(37)通过管道与还原气气源相连通，还原气气源选用H2和/或CO。
  4. 根据权利要求1所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统，其特征在于，矿相转化器(11)底部设有进气口并与氮气气源管道相连通，矿相转化器(11)顶部设有换气口并与第四旋风分离器(12)连通；第四旋风分离器(12)的底部出料口和矿相转化器(11)连通，第四旋风分离器(12)的顶部出料口和悬浮预热分解炉(7)连通；
    所述的矿相转化器(11)的主体包括矿相转化器壳体，形成还原室，壳体上设置有矿相转化进料口和矿相转化出料口，在位于上方的壳体内侧间隔设置多个顶部挡板，在位于下方的壳体内侧交错设置多个第二底部挡板，并在顶部挡板的正下方设置有第一底部挡板，第一底部挡板和对应的顶部挡板之间留有空隙，顶部挡板和第一底部挡板和第二底部挡板共同构成矿粉流动通道，顶部挡板和第二底部挡板之间形成的空间为垂直通道；在设置第一底部挡板和第二底部挡板一侧的壳体上设置有矿相转化布风板，用以平均分布气流；在每个垂直通道内设置均设置有矿相转化进气口，用以提供矿粉稳定流动所需的松动风及流化风。
  5. 根据权利要求1所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统，其特征在于，所述的第一流化密封阀(10)和第二流化密封阀(13)的主体包括流化密封壳体，流化密封壳体形成流化室，流化室上方设置有顶部流化密封挡板，在顶部流化密封挡板正下方设置有底部流化密封挡板，并在底部流化密封挡板一侧设置有流化密封布风板，用于平均分布气流；在每个垂直通道内设置有氮气进气口，用以提供矿粉稳定流动所需的松动风及流化风；
    第一流化密封阀(10)与第二流化密封阀(13)底部均设有进气口并与氮气气源管道连通。
  6. 根据权利要求1所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统，其特征在于，球磨机(17)排料口与螺旋分级机(18)给料口连通，螺旋分级机(18)溢流口通过管道与第一酸浸槽(19)入料口连通，螺旋分级机(18)返砂口与球磨机(17)连通；
    第一酸浸槽(19)排液口通过管道与第二酸浸槽(25)连通；
    混合稀土精矿悬浮态矿相转化-清洁浸出的系统中，还包括第一压滤机(20)，第一酸浸槽(19)的出料口与第一压滤机(20)相对，第一压滤机(20)排料口与碱浸槽(21)连通，第一压滤机(20)下方排液口通过管道与第二酸浸槽(25)连通；
    碱浸槽(21)和水洗槽(22)连通，水洗槽(22)排液口通过管道与水洗液回收槽(24)连通；
    和/或，混合稀土精矿悬浮态矿相转化-清洁浸出的系统中，还包括第二压滤机(23)，水 洗槽(22)的出料口与第二压滤机(23)入料口连通，第二压滤机(23)排料口与第二酸浸槽(25)相对，第二压滤机(23)下方排液口通过管道与水洗液回收槽(24)连通；
    第二酸浸槽(25)和中和槽(26)连通，中和槽(26)排液口与氯化稀土产品槽(27)相对；中和槽(26)排料口与含钍渣池(28)相对。
  7. 权利要求1-6任意一项所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统的使用方法，其特征在于，按以下步骤进行：
    S1、准备
    使文丘里干燥器(4)、第一旋风分离器(5)、第二旋风分离器(6)、悬浮预热分解炉(7)、第三旋风分离器(9)内产生负压；文丘里干燥器(4)内通入燃烧烟气，用以脱除混合稀土精矿粉吸附水并对混合稀土精矿粉进行预热；
    S2、干燥分离
    将给料仓(1)内混合稀土精矿粉运送到文丘里干燥器(4)内，经干燥脱水后，预热至150～200℃的混合稀土精矿粉送入第一旋风分离器(5)内，经旋风分离后，底部物料经由第二旋风分离器(6)送入悬浮预热分解炉(7)内；
    S3、悬浮预热分解
    烟气经由悬浮预热分解炉(7)底部的进气口通入，进入悬浮预热分解炉(7)内的物料预热分解并处于悬浮状态，控制物料温度在550～800℃，停留时间1～10min，得到悬浮预热分解后的物料；
    S4、矿相转化
    完成悬浮预热分解后的物料进入第三旋风分离器(9)内，经旋风分离后，底部物料首先进入第一流化密封阀(10)中隔绝氧气及空气，随后物料进入矿相转化器(11)中，矿相转化器(11)通入氮气作为保护气，物料在保护气作用下保持悬浮状态并完成矿相转化，控制物料温度在450～650℃，停留时间1～2.5h，得到矿相转化后的物料；
    S5、水冷
    完成矿相转化后的物料经由第二流化密封阀(13)将产物排出，随后矿相转化产物经由第五旋风分离器(14)排入水冷槽(16)内进行水冷，最后通入球磨机(17)中；
    S6、清洁浸出
    (1)物料在球磨机(17)内磨细后，控制物料粒度在-45μm含量占85～95wt％，随后排入第一酸浸槽(19)；
    (2)第一酸浸槽(19)内进行盐酸浸出，所用盐酸浓度为8～13mol/L，按质量比，混合稀土精矿粉中REO︰盐酸＝1︰(1～3)，浸出温度为65～100℃，浸出时间为1～3h；酸浸后压 滤得到的浸出酸液通入第二酸浸槽(25)内；
    (3)酸浸渣通入碱浸槽(21)内进行NaOH碱分解，NaOH的质量浓度为50％～80％，按质量比，酸浸渣中REO︰NaOH＝1︰(0.5～2.5)，温度为130～220℃，时间为1～2h；碱分解渣排入水洗槽(22)内进行水洗，水洗温度为55～100℃，水洗终点pH＝7～9；
    (4)水洗后的碱分解渣压滤，滤液通入水洗液回收槽(24)内，滤渣通入第二酸浸槽(25)；
    (5)滤渣在第二酸浸槽(25)内与通入的浸出酸液混合后共同搅拌酸浸，酸浸温度为40～80℃，按质量比，滤渣：浸出酸液为1︰(5～10)，时间为1～3h，得到浸出产物；
    (6)浸出产物通入中和槽(26)后，向中和槽(26)内加入NaOH并持续搅拌混合，NaOH的质量浓度为15％～35％，搅拌时间1～2.5h，终点pH＝4～5；完成中和后，中和液通入氯化稀土产品槽(27)内，中和渣通入含钍渣池(28)。
  8. 根据权利要求7所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统的使用方法，其特征在于，预热至150～200℃的混合稀土精矿粉通入第一旋风分离器(5)后，分离出的粉尘通入电除尘器(29)，除尘后的烟气通入电除尘器(30)进行净化处理，随后由烟囱(32)排出；
    电除尘器(29)收集的粉尘在返灰风机(34)的作用下经由气力提升泵(33)返回第三旋风分离器(9)内。
  9. 根据权利要求7所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统的使用方法，其特征在于，通入悬浮预热分解炉(7)的烟气是通过燃烧通入燃烧器(8)内的空气及还原气混合气体产生，悬浮预热分解炉(7)运行过程中产生的烟气经由第三旋风分离器(9)与第二旋风分离器(6)返回文丘里干燥器(4)以实现余热利用；
    第五旋风分离器(14)分离出的粉尘及气体返回第三旋风分离器(9)；
    第六旋风分离器(15)分离出的粉尘及气体返回第五旋风分离器(14)，第五旋风分离器(14)分离出的多余粉尘颗粒在通过管道时进入第二灰斗(36)。
  10. 根据权利要求7所述的混合稀土精矿悬浮态矿相转化-清洁浸出的系统的使用方法，其特征在于，上述系统的使用方法中，螺旋分级机(18)对磨矿物料分级后返砂返回球磨机(17)再磨。
PCT/CN2023/117725 2022-11-03 2023-09-08 混合稀土精矿悬浮态矿相转化-清洁浸出的系统及其使用方法 WO2024093526A1 (zh)

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