Process method and device for ammonium chloride roasting treatment of ionic rare earth ore

Abstract

This invention relates to a process and apparatus for roasting ionic rare earth ores with ammonium chloride. The process involves adding a decomposition aid to the rare earth ore, mixing thoroughly to obtain a mixture, low-temperature roasting of the mixture, water leaching and roasting products, and filtering to obtain a low-impurity rare earth water leaching solution and water leaching residue. Acid-dissolved water leaching residue is then filtered to obtain a superior solution and superior leaching residue, and acid-dissolved superior leaching residue is filtered to obtain a deep solution and deep leaching residue. The superior solution is added to the low-impurity rare earth water leaching solution, and the deep solution, after conditioning and impurity removal, is combined with the low-impurity rare earth water leaching solution and then fed into an extraction tank for separation. The deep leaching residue is stored as solid waste. This invention uses ammonium chloride as a roasting and decomposition aid, which has a certain separation effect on rare earths and impurities, and can directly obtain a large amount of clean rare earth feed solution with low impurities, without the need for complex impurity removal processes. Furthermore, this invention uses water to recover ammonium carbonate and / or ammonium bicarbonate and / or ammonia, the flue gas products from rare earth ore roasting, and the resulting alkaline solution can be used as a saponifying agent in the rare earth separation process.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgy and industrial environmental protection technology, specifically relating to a process and apparatus for roasting ion-type rare earth ores with ammonium chloride. Background Technology

[0002] In the rare earth smelting and separation process, smelting and separation plants generate large amounts of ammonium chloride wastewater. Due to the presence of ammonia nitrogen and chloride ions in this wastewater, direct discharge would severely pollute water bodies. Ammonia nitrogen consumes dissolved oxygen in the water, accelerating eutrophication; moreover, ammonia nitrogen can be converted into nitrate and nitrite nitrogen by microorganisms in the water, which are toxic to humans. Furthermore, large-scale discharge of ammonium chloride negatively impacts soil chloride ion concentration and pH levels. Smelting and separation plants typically recover ammonium chloride wastewater using evaporation and concentration equipment such as MVR (Medium-Vacuum Reduction) to obtain solid ammonium chloride for sale. In the initial stage of rare earth smelting, hydrochloric acid is used to dissolve rare earth mineral raw materials into rare earth chloride solution. To increase rare earth yield, excessive amounts of hydrochloric acid are often added during production, leading to waste and the leaching of large amounts of impurity ions such as Al, Fe, and F into the rare earth chloride solution, reducing its quality and affecting subsequent rare earth extraction and separation processes. Rare earth carbonate minerals generate a large amount of carbon dioxide gas during the hydrochloric acid dissolution process, which affects the leaching efficiency of rare earths.

[0003] In the prior art, Chinese patent CN201410511130.1 discloses a leaching process for cerium fluorocarbonate ore with a grade of 45%-60%. The process involves first drying and then calcining the carbonate ore, followed by adding hydrochloric acid to dissolve most of the rare earth elements. The residue undergoes an alkaline conversion reaction for more than 4 hours, is washed with water until neutral to remove F and Al impurities, and then the alkaline conversion residue is reacted with hydrochloric acid again to obtain a rare earth solution and a Ce-enriched residue. Its advantages include a praseodymium-neodymium leaching yield of over 98%, far exceeding the original leaching levels, and a reduction in hydrogen fluoride gas generation. However, this process consumes a large amount of alkali, significantly increasing costs, and generates substantial amounts of alkaline conversion washing wastewater, resulting in a significant increase in production wastewater. Chinese patent CN202511013076.2 discloses a method to prevent ammonium chloride from sublimating and escaping during the roasting process. It uses ammonium chloride to treat NdFeB waste, recovering rare earth elements through steps such as low-temperature chlorination, water leaching, precipitation, iron removal, oxalic acid precipitation, and calcination, and then re-condensing and recovering ammonium chloride. This method omits the hydrochloric acid dissolution step, but the subsequent impurity removal process is time-consuming and costly. Chinese patent CN202410988452.9 discloses a method for treating ionic rare earth wastewater and waste gas, achieving zero-emission recycling. It uses calcium hydroxide to pretreat the wastewater, obtaining ammonia water, then removing the ammonia, and absorbing carbon dioxide from rare earth production or other industrial waste gas to form ammonium carbonate for reuse in rare earth heap leaching processes. This is a conventional lime stripping process that can treat wastewater, but it does not involve the upstream rare earth acid dissolution and impurity removal process. The 2011 paper "Research on the Process of Preparing High-Purity Manganese Carbonate by Roasting Rhodochrosite with Ammonium Chloride" published in *Inorganic Salts Industry* used ammonium chloride to roast rhodochrosite, with the carbonization tail gas used to precipitate manganese chloride. However, the technique of adjusting process parameters to increase the primary leaching rate resulted in high impurities in the feed solution, requiring subsequent conditioning and impurity removal of the entire solution. Furthermore, the paper did not address the low ammonium carbonate recovery rate, nor did it consider continuous production or the control of anions in the rare earth feed solution entering the leaching tank.

[0004] It can be seen that the existing processes described above suffer from problems such as high acid consumption, complex procedures, insufficiently clean output liquid, and complicated recovery processes. Therefore, developing a low-carbon, low-cost, green, and efficient rare earth pretreatment and smelting technology is imperative and of great significance to the rare earth smelting industry. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a process and apparatus for roasting ionic rare earth ores with ammonium chloride. This process utilizes inexpensive recycled ammonium chloride as a raw material to decompose rare earth ores, resulting in a more environmentally friendly operating environment compared to traditional hydrochloric acid dissolution. It is also cost-effective and significantly reduces the amount of corrosive HCl gas produced during the production process. Furthermore, ammonium chloride roasting has a certain separation effect on rare earths and impurities, yielding a clean rare earth solution. The low-impurity rare earth chloride solution can be recovered separately, while non-rare earth impurities are enriched in the high-quality slag and recovered separately.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a process for roasting ion-adsorption rare earth ores with ammonium chloride, the method comprising:

[0007] S1. Preparation of mixture: Add decomposition aid to rare earth ore and mix evenly to obtain mixture;

[0008] S2, Calcination mixture: The mixture is calcined at a temperature of 200-600℃ to obtain the calcined product;

[0009] S3, Water-immersed roasted product: Water is added to the roasted product for water immersion, and the product is filtered and separated to obtain a low-impurity rare earth water immersion liquid and water immersion residue.

[0010] S4. Acid-dissolving water leaching residue: Hydrochloric acid is added to the water leaching residue, and the pH value is controlled to carry out the dissolution reaction; the solution and the superior solution residue are obtained by filtration, and the superior solution is added to the low-impurity rare earth water leaching solution.

[0011] S5. Acid dissolution of superior soluble residue: Hydrochloric acid is slowly added to the superior soluble residue to control the pH value and carry out the dissolution reaction; the deep solution and the deep soluble residue are obtained by filtration. The deep solution is combined with low-impurity rare earth water leaching solution after conditioning and impurity removal, and then enters the extraction tank for separation; the deep soluble residue is stored as solid waste.

[0012] Furthermore, in step S1, the rare earth ore is selected from one or more of ionic rare earth oxide ore, ionic rare earth carbonate ore, and rare earth concentrates.

[0013] Furthermore, in step S1, the decomposition aid is selected from one of industrial ammonium chloride, agricultural ammonium chloride, and solid ammonium chloride recovered by evaporation and concentration in a smelting separation plant;

[0014] The amount of the decomposition aid is 20-160 wt% of the weight ratio of rare earth oxides in the rare earth ore.

[0015] Furthermore, in step S2, the mixture is calcined at 200-600°C for 1-5 hours.

[0016] Furthermore, in step S2, the roasting flue gas generated during the roasting process is introduced into a two-stage water absorption device through a conduit, and the roasting flue gas products are absorbed by water.

[0017] When rare earth ore uses rare earth oxide ore as raw material, the first-stage absorption product is a mixture of ammonia and ammonium chloride; when rare earth ore uses rare earth carbonate ore as raw material, the first-stage absorption product is a solution of ammonium carbonate and / or ammonium bicarbonate.

[0018] Furthermore, in step S3, the temperature of the water immersion process is 60-100℃, and the water immersion time is 0.5-6 hours.

[0019] Furthermore, in step S4, the concentration of hydrochloric acid is 0.5-10 mol / L, and the pH value of the dissolution reaction endpoint of adding hydrochloric acid to the water-leached residue is controlled to be in the range of 1-6.

[0020] The dissolution reaction of the water-leached residue with hydrochloric acid is carried out at a temperature of 10-60℃ for a time of 0.5-3h.

[0021] Furthermore, in step S4, the pH range of the dissolution reaction endpoint of adding hydrochloric acid to the water-leached residue is controlled to be 2-5.

[0022] Furthermore, in step S5, the concentration of hydrochloric acid is 3-10 mol / L, and the pH value of the final dissolution reaction of hydrochloric acid in the superior slag is controlled to be in the range of 1-3.

[0023] The temperature of the hydrochloric acid dissolution reaction in the slag is 10-60℃, and the time is 0.5-3h.

[0024] This invention also provides a process apparatus for roasting ion-adsorption rare earth ores with ammonium chloride. The apparatus is used to implement the process method for roasting ion-adsorption rare earth ores with ammonium chloride, and the apparatus includes:

[0025] The roasting unit includes a feeding module, a roasting kiln, a lifting platform, and a discharge port. The feeding module is equipped with a feeding pipe with a feeding motor and a mixing chamber with a stirring motor. The mixing chamber has a feeding port in the middle and a discharge valve at the bottom. When the discharge valve is open, the mixing chamber is connected to the front end of the feeding pipe, and the end of the feeding pipe is connected to the feeding end of the roasting kiln. The center of the discharge end of the roasting kiln and the center of the discharge port are on the same vertical line. The roasting kiln has an air outlet connected to a dust removal system. The roasting kiln is fixedly installed on the lifting platform.

[0026] The water immersion tank has a water inlet, a roasting product inlet, and a variable frequency speed control motor stirring paddle at the top. The bottom of the water immersion tank has a low-impurity rare earth water immersion liquid outlet. A detachable filter screen is installed above the low-impurity rare earth water immersion liquid outlet to collect water immersion residue. At the same time, the detachable filter screen is lower than the stirring trajectory of the stirring paddle.

[0027] An acid leaching tank is provided with an acid inlet and a water leaching residue inlet at the top, and a high-quality solution outlet at the bottom. A detachable filter screen is provided above the high-quality solution outlet for collecting the high-quality leaching residue.

[0028] The deep dissolving tank has an acid inlet and a slag inlet at the top, a deep solution outlet at the bottom, and a removable filter screen above the deep solution outlet for collecting the slag.

[0029] Furthermore, the dust removal facility includes a two-stage water suction device, and the air outlet is connected to the two-stage water suction device via an exhaust gas delivery pipeline.

[0030] The beneficial effects of this invention are as follows: The process and apparatus for treating ionic rare earth ores by ammonium chloride roasting provided by this invention involve adding decomposition aids to rare earth ores, mixing them evenly to obtain a mixture, a low-temperature roasted mixture, a water-leached roasting product, and filtering to separate low-impurity rare earth water-leached liquid and water-leached residue. Acid-dissolved water-leached residue is filtered to obtain a superior solution and superior leached residue, and acid-dissolved superior leached residue is filtered to obtain a deep solution and deep leached residue. The superior solution is added to the low-impurity rare earth water-leached liquid, and the deep solution, after conditioning and impurity removal, is combined with the low-impurity rare earth water-leached liquid and then enters an extraction tank for separation. The deep leached residue is stored as solid waste.

[0031] Compared with existing technologies, the main advantages of this invention are that the method provided by this invention uses inexpensive recycled ammonium chloride as a raw material to decompose rare earth ores. The operating environment is more friendly than that of traditional hydrochloric acid dissolution, the cost is low, and the production process significantly reduces the amount of HCl acid corrosion gas, making the rare earth pretreatment process more environmentally friendly. Moreover, in the method provided by this invention, ammonium chloride is used as a roasting decomposition aid, which has a certain separation effect on rare earths and impurities, and can directly obtain a large amount of clean rare earth feed solution with low impurities, without the need for complex impurity removal processes; the low-impurity rare earth chloride feed solution can be recovered separately, and non-rare earth impurities are enriched in the deep dissolution slag and recovered separately. In addition, this invention uses water to recover the flue gas products of rare earth ore roasting, namely ammonium carbonate and / or ammonium bicarbonate and / or ammonia. The resulting alkaline solution can be used as a saponifying agent in the rare earth separation process, which reduces alkali consumption and costs while also reducing the emission of gaseous pollutants. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process method for roasting ion-adsorption rare earth ores with ammonium chloride according to the present invention.

[0033] Figure 2 A schematic diagram of the process apparatus for roasting ion-adsorption rare earth ores with ammonium chloride according to the present invention.

[0034] In the diagram, 1—feeding motor, 2—stirring motor, 3—feed inlet, 4—feed dynamic seal, 5—air outlet, 6—calcining kiln, 7—air inlet / outlet, 8—discharge dynamic seal, 9—discharge outlet, 10—lifting platform, 11—tail gas conveying pipeline, 12—water inlet, 13—two-stage water suction device, 14—water suction solution outlet. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be further clearly and completely described below with reference to the accompanying drawings and examples. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that in the description of the embodiments of the present invention, the terms "upper," "lower," "front," "rear," "front," "back," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] To address the problems of high acid consumption, complex processes, insufficiently clean output solutions, and complicated recovery processes in existing rare earth pretreatment smelting processes, this embodiment provides a process and apparatus for roasting ionic rare earth ores with ammonium chloride. This method uses inexpensive recycled ammonium chloride as a raw material to decompose rare earth ores, resulting in a more environmentally friendly operating environment compared to traditional hydrochloric acid dissolution. It is also cost-effective and significantly reduces the amount of corrosive HCl gas produced during the production process, making the rare earth pretreatment process more environmentally friendly. Furthermore, the method provided in this embodiment uses ammonium chloride as a roasting and decomposition aid, which has a certain separation effect on rare earths and impurities, directly yielding a large quantity of clean rare earth solution with low impurities, eliminating the need for complex impurity removal processes. The low-impurity rare earth chloride solution can be recovered separately, while non-rare earth impurities are enriched in the deep-dissolved slag and recovered separately.

[0038] In addition, the method uses water to recover the flue gas products of rare earth ore roasting reaction, namely ammonium carbonate and / or ammonium bicarbonate and / or ammonia. The resulting alkaline solution can be used as a saponifying agent in the rare earth separation process, which reduces alkali consumption and cost in production, while also reducing the emission of gaseous pollutants.

[0039] like Figure 1 As shown in the figure, an embodiment of the present invention provides a process for roasting ion-adsorption rare earth ores with ammonium chloride, the method comprising:

[0040] S1. Preparation of mixture: Add decomposition aid to rare earth ore and mix evenly to obtain mixture;

[0041] Specifically, in step S1, the rare earth ore is selected from one or more of ionic rare earth oxide ore, ionic rare earth carbonate ore, and rare earth concentrates.

[0042] Optionally, in step S1, the decomposition aid is selected from industrial ammonium chloride, agricultural ammonium chloride, and solid ammonium chloride recovered by evaporation and concentration in a smelting separation plant.

[0043] Optionally, in step S1, the amount of the decomposition aid is 20-160 wt% of the weight ratio of rare earth oxides (REO) in the rare earth ore.

[0044] S2, Calcination mixture: The mixture is calcined at a temperature of 200-600℃ to obtain the calcined product;

[0045] Optionally, in step S2, the mixture is calcined at 200-600°C for 1-5 hours.

[0046] Optionally, in step S2, the roasting flue gas generated during the roasting process is introduced into a two-stage water absorption device via a conduit, where water is used to absorb the roasting flue gas products. When rare earth ore uses rare earth oxide ore as raw material, the first-stage absorption product is a mixture of ammonia and ammonium chloride; when rare earth ore uses rare earth carbonate ore as raw material, the first-stage absorption product is a solution of ammonium carbonate and / or ammonium bicarbonate. The first-stage absorption product can be used as a saponifying agent in the rare earth separation process, reducing alkali consumption and costs while also reducing the emission of gaseous pollutants.

[0047] S3, Water-immersed roasted product: Water is added to the roasted product for water immersion, and the product is filtered and separated to obtain a low-impurity rare earth water immersion solution containing mainly rare earth elements and water immersion residue.

[0048] Specifically, in step S3, the water immersion temperature is 60-100℃, and the water immersion time is 0.5-6 hours.

[0049] Specifically, the impurities in the low-impurity rare earth aqueous leaching solution include aluminum, iron, uranium, thorium, and fluorine, wherein the aluminum content is 1-100 mg / L, the iron content is 1-50 mg / L, the uranium content is 0.01-2 mg / L, the thorium content is 0.01-5 mg / L, and the fluorine content is 1-100 mg / L. This method can directly obtain a large quantity of low-impurity rare earth feed solution, which can be directly introduced into the extraction tank for separation without the need for impurity removal.

[0050] S4. Acid-dissolved water leaching residue: Hydrochloric acid is slowly added to the water leaching residue to control the pH value and carry out the dissolution reaction; the superior solution and the superior leaching residue (i.e., acid-dissolved residue) are obtained by filtration and separation, and the superior solution is incorporated into the low-impurity rare earth water leaching solution.

[0051] Optionally, in step S4, the concentration of hydrochloric acid is 0.5-10 mol / L, and the pH value at the endpoint of the dissolution reaction of hydrochloric acid in the water-leached residue is controlled to be in the range of 1-6.

[0052] Specifically, in step S4, the temperature of the dissolution reaction of adding hydrochloric acid to the water-leached residue is 10-60℃, and the time is 0.5-3h.

[0053] Optionally, in step S4, the pH range of the final dissolution reaction endpoint of adding hydrochloric acid to the water-leached residue is controlled to be 2-5.

[0054] The impurities and their content in the superior solution obtained in step S4 are comparable to those in the low-impurity rare earth aqueous leaching solution. They can be incorporated into the low-impurity rare earth aqueous leaching solution and recycled as a clean rare earth extraction feed solution, which is then introduced into the extraction tank for separation.

[0055] S5. Acid dissolution of superior soluble residue: Hydrochloric acid is slowly added to the superior soluble residue to control the pH value and carry out the dissolution reaction; the deep solution and the deep soluble residue are obtained by filtration and separation. The deep solution is combined with low-impurity rare earth water leaching solution after conditioning and impurity removal, and then enters the extraction tank for separation; the deep soluble residue is stored as solid waste.

[0056] Optionally, in step S5, the concentration of hydrochloric acid is 3-10 mol / L, and the pH value at the endpoint of the dissolution reaction of adding hydrochloric acid to the slag is controlled to be in the range of 1-3.

[0057] Specifically, in step S5, the temperature of the hydrochloric acid dissolution reaction in the slag is 10-60℃, and the time is 0.5-3h.

[0058] like Figure 1-2 As shown, this invention also provides a process apparatus for roasting ion-adsorption rare earth ores with ammonium chloride, used to implement the above-mentioned process method for roasting ion-adsorption rare earth ores with ammonium chloride. The apparatus includes:

[0059] The roasting unit includes a feeding module, a roasting kiln 6, a lifting platform 10, and a discharge port 9. The feeding module includes a feeding pipe with a feeding motor 1 and a mixing chamber with a stirring motor 2. A feeding port 3 is located in the middle of the mixing chamber, and a discharge valve is located at the bottom of the mixing chamber. When the discharge valve is open, the mixing chamber is connected to the front end of the feeding pipe, and the end of the feeding pipe is connected to the feeding end of the roasting kiln 6. The center of the discharge end of the roasting kiln 6 and the center of the discharge port 9 are on the same vertical line. An air outlet 5 is provided on the roasting kiln 6, and the air outlet 5 is connected to a dust removal system. The roasting kiln 6 is fixedly installed on the lifting platform 10.

[0060] The water immersion tank has a water inlet, a roasting product inlet, and a variable frequency speed control motor stirring paddle at the top. The bottom of the water immersion tank has a low-impurity rare earth water immersion liquid outlet. A detachable filter screen is installed above the low-impurity rare earth water immersion liquid outlet to collect water immersion residue. At the same time, the detachable filter screen is lower than the stirring trajectory of the stirring paddle.

[0061] An acid leaching tank is provided with an acid inlet and a water leaching residue inlet at the top, and a high-quality solution outlet at the bottom. A detachable filter screen is provided above the high-quality solution outlet for collecting the high-quality leaching residue.

[0062] The deep dissolving tank has an acid inlet and a slag inlet at the top, a deep solution outlet at the bottom, and a removable filter screen above the deep solution outlet for collecting the slag.

[0063] The calcining kiln 6 is a double-layered rotating structure with an outer stationary cylinder and an inner rotating cylinder, coaxially arranged. The inner cylinder is equipped with a tire, support rollers, and a transmission gear ring to achieve circumferential rotation, allowing the mixture to undergo calcination and pyrolysis within its space. Simultaneously, a lifting platform 10 raises the feed end of the calcining kiln 6 at a certain angle, causing the mixture to slowly move towards the discharge end under the influence of the rotating inner cylinder and gravity. This structure allows for setting the feed end elevation angle of the calcining kiln 6 according to the required calcination time, thus determining the residence time (i.e., calcination time) of the mixture within the kiln 6. Furthermore, the more complex movement path of the mixture during calcination results in more uniform heating, improving process efficiency and product quality.

[0064] Rare earth ore with added decomposition aids enters the mixing chamber through the feed inlet and is mixed evenly under the stirring action of the stirring motor 2 to obtain a mixture. The mixture enters the feeding pipe through the discharge valve at the bottom of the mixing chamber and is conveyed to the inner process cylinder located in the roasting kiln 6 by the screw driven by the feeding motor 1 through the feed end of the roasting kiln 6 for roasting and pyrolysis. The lifting angle of the feed end of the roasting kiln 6 is set according to the set roasting time of the mixture, and the mixture slowly moves towards the discharge end of the roasting kiln 6 under the action of the rotation of the inner process cylinder and gravity. After reaching the end of the inner process cylinder, the roasting is completed, and the roasted product directly enters the discharge port 9 under the action of gravity and is then conveyed to the water immersion tank. During the removal of the roasted product, air is introduced through the inlet / outlet 7. In addition, the inlet / outlet 7 can also serve as a backup outlet. If the outlet 5 is blocked or other malfunctions occur, the flue gas can be switched to the inlet / outlet 7 for discharge.

[0065] Specifically, the feeding end of the roasting kiln 6 is equipped with a feeding dynamic seal 4, and the discharging end of the roasting kiln 6 is equipped with a discharging dynamic seal 8. The feeding dynamic seal 4 is located between the stationary outer cylinder and the rotatable inner process cylinder at the feeding end, and the discharging dynamic seal 8 is located between the stationary outer cylinder and the rotatable inner process cylinder at the discharging end. This ensures airtightness during the reaction process, allowing all the flue gas generated during roasting to be drawn out to the two-stage water suction device and absorbed. Simultaneously, it also isolates internal and external gas leakage, prevents cold air infiltration, and ensures stable operation under a closed atmosphere.

[0066] Specifically, the dust removal facility includes a two-stage water suction device 13. The air outlet 5 is connected to the two-stage water suction device 13 via the exhaust gas conveying pipeline 11. The flue gas generated during roasting enters the two-stage water suction device 13 through the air outlet 5 and along the exhaust gas conveying pipeline 11. The exhaust gas conveying pipeline 11 is covered with a polyurethane insulation layer.

[0067] Optionally, the two-stage water suction device 13 is provided with a water inlet 12 at the top and a water suction solution outlet 14 at the bottom. When rare earth ore uses rare earth oxide ore as raw material, the two-stage water suction device 13 is a collection tank for ammonia water and ammonium chloride mixture; when rare earth ore uses rare earth carbonate ore as raw material, the two-stage water suction device 13 is a collection tank for ammonium carbonate and / or ammonium bicarbonate solution.

[0068] Specifically, the deep solution is a rare earth liquid with a high impurity content, which needs to be conditioned and purified through a purification process before it can be combined with a low-impurity rare earth water leaching solution and enter the extraction tank for separation; the deep solution residue is stored as solid waste.

[0069] Example 1

[0070] This embodiment 1 uses the aforementioned ammonium chloride roasting process and apparatus to process rare earth carbonate raw materials.

[0071] (1) Take 1000g of rare earth carbonate ore raw material (containing REO ~54%), add 840g of ammonium chloride solid recovered by evaporation and concentration (ammonium chloride content 98%), mix evenly and put it into the feed inlet 3. Raise the feed end of the roasting kiln 6 to an angle of 2.5° with the ground by lifting platform 10, control the residence time of the mixture in the high temperature zone, set the temperature of the high temperature zone of the kiln to 300℃, and the residence time of the sample in the high temperature zone is 3.5 hours. The roasting flue gas is introduced into the two-stage water absorption device 13 through the tail gas conveying pipeline 11. The first stage absorption obtains an ammonium carbonate solution with an alkalinity of 5.4mol / L. The absorbed ammonium carbonate solution is used for saponification of extractant P507, and the saponification waste water with pH 6 is returned to the absorption device for the next absorption.

[0072] (2) The roasted product was mixed with water in a water immersion tank, stirred and heated to 95°C for 1 hour, filtered, and a low-impurity rare earth water immersion solution was obtained. The rare earth concentration was 0.32 mol / L, the aluminum content was <10 mg / L, the iron content was <1 mg / L, the uranium content was <0.1 mg / L, the thorium content was <0.5 mg / L, and the fluorine content was 6.12 mg / L. This solution was used as a clean rare earth extraction feed solution for recovery.

[0073] (3) The water leaching residue was dissolved in 6 mol / L hydrochloric acid until pH=5.0, and the resulting solution had a rare earth concentration of 0.32 mol / L, an aluminum content of <10 mg / L, an iron content of <1 mg / L, a uranium content of <0.1 mg / L, a thorium content of <0.5 mg / L, and a fluorine content of 26 mg / L. This solution was then added to the low-impurity rare earth water leaching solution to be used as a clean rare earth extraction feed for recovery.

[0074] (4) The high-quality slag is dissolved in 10 mol / L hydrochloric acid until pH=1 to obtain a deep solution. After conditioning and removing impurities, the deep solution is added to the low-impurity material solution and then combined into the extraction tank for separation. The deep-dissolved slag is stored as solid waste.

[0075] Example 2

[0076] This embodiment 2 uses the aforementioned ammonium chloride roasting process and apparatus to process rare earth oxide ore raw materials.

[0077] (1) Take 1000g of rare earth oxide ore raw material (containing REO ~89%), add 500g of industrial ammonium chloride solid (ammonium chloride content 99%), mix evenly and put it into the feed inlet 3. The feed end of the roasting kiln 6 is raised to an angle of 3.3° with the ground by the lifting platform 10. The temperature of the high temperature zone of the kiln is set at 350℃, and the sample stays in the high temperature zone for 3 hours. The roasting flue gas is introduced into the two-stage water absorption device 13 through the tail gas conveying pipeline 11. The first-stage absorption product is a mixture of ammonia and ammonium chloride with an alkalinity of 3.4mol / L. The absorbed ammonia solution is used for the saponification of extractant P507. The saponification waste water with pH 6 is returned to the absorption device for the next absorption.

[0078] (2) The roasted product was mixed with water in a water immersion tank, stirred and heated to 95°C for 1 hour, filtered, and a low-impurity rare earth water immersion solution was obtained. The rare earth concentration was 0.35 mol / L, the aluminum content was <10 mg / L, the iron content was <1 mg / L, the uranium content was <0.1 mg / L, the thorium content was <0.5 mg / L, and the fluorine content was 15.3 mg / L. This solution was used as a clean rare earth extraction feed solution for recovery.

[0079] (3) The water leaching residue was dissolved in 3 mol / L hydrochloric acid until pH=2.5, and the resulting solution had a rare earth concentration of 0.42 mol / L, an aluminum content of 40 mg / L, an iron content of <1 mg / L, a uranium content of <0.1 mg / L, a thorium content of <0.5 mg / L, and a fluorine content of 90 mg / L. This solution was then added to a low-impurity rare earth water leaching solution to be used as a clean rare earth extraction feed for recovery.

[0080] (4) The high-quality slag is dissolved in 6 mol / L hydrochloric acid until pH=1.0 to obtain a deep solution. After conditioning and removing impurities, the deep solution is added to the low-impurity material solution and then combined into the extraction tank for separation. The deep-dissolved slag is stored as solid waste.

[0081] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. Thus, the invention also intends to include such variations and adaptations if they fall within the scope of the claims and their equivalents.

[0082] The above embodiments are merely illustrative examples of the present invention. The present invention may also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of protection of the present invention should be defined by the claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A process for roasting ion-adsorption rare earth ores with ammonium chloride, characterized in that, The method includes: S1. Preparation of mixture: Add decomposition aid to rare earth ore and mix evenly to obtain mixture; S2, Calcination mixture: The mixture is calcined at a temperature of 200-600℃ to obtain the calcined product; S3, Water-immersed roasted product: Water is added to the roasted product for water immersion, and the product is filtered and separated to obtain a low-impurity rare earth water immersion liquid and water immersion residue. S4. Acid-dissolving water leaching residue: Hydrochloric acid is added to the water leaching residue, and the pH value is controlled to carry out the dissolution reaction; the solution and the superior solution residue are obtained by filtration, and the superior solution is added to the low-impurity rare earth water leaching solution. S5. Acid dissolution of superior soluble residue: Hydrochloric acid is slowly added to the superior soluble residue to control the pH value and carry out the dissolution reaction; the deep solution and the deep soluble residue are obtained by filtration. The deep solution is combined with low-impurity rare earth water leaching solution after conditioning and impurity removal, and then enters the extraction tank for separation; the deep soluble residue is stored as solid waste.

2. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S1, the rare earth ore is selected from one or more of ionic rare earth oxide ore, ionic rare earth carbonate ore, and rare earth concentrates.

3. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S1, the decomposition aid is selected from one of industrial ammonium chloride, agricultural ammonium chloride, and solid ammonium chloride recovered by evaporation and concentration in a smelting separation plant; The amount of the decomposition aid is 20-160 wt% of the weight ratio of rare earth oxides in the rare earth ore.

4. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S2, the mixture is calcined at 200-600℃ for 1-5 hours.

5. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S2, the roasting flue gas generated during the roasting process is introduced into a two-stage water absorption device through a conduit, and the roasting flue gas products are absorbed by water. When rare earth ore uses rare earth oxide ore as raw material, the first-stage absorption product is a mixture of ammonia and ammonium chloride; when rare earth ore uses rare earth carbonate ore as raw material, the first-stage absorption product is a solution of ammonium carbonate and / or ammonium bicarbonate.

6. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S3, the water immersion temperature is 60-100℃ and the immersion time is 0.5-6 hours.

7. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S4, the concentration of hydrochloric acid is 0.5-10 mol / L, and the pH value of the dissolution reaction endpoint of hydrochloric acid in the water-leached residue is controlled to be in the range of 1-6. The dissolution reaction of the water-leached residue with hydrochloric acid is carried out at a temperature of 10-60℃ for 0.5-3 hours.

8. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S4, the pH range of the final dissolution reaction of adding hydrochloric acid to the water-leached residue is controlled to be 2-5.

9. The process for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 1, characterized in that, In step S5, the concentration of hydrochloric acid is 3-10 mol / L, and the pH value of the final dissolution reaction of hydrochloric acid in the superior slag is controlled to be in the range of 1-3. The temperature of the hydrochloric acid dissolution reaction in the slag is 10-60℃, and the time is 0.5-3h.

10. A process apparatus for roasting ion-adsorption rare earth ores with ammonium chloride, characterized in that, The apparatus is used to implement the process method for roasting ion-adsorption rare earth ores with ammonium chloride as described in any one of claims 1-9, and the apparatus comprises: The roasting unit includes a feeding module, a roasting kiln, a lifting platform, and a discharge port. The feeding module is equipped with a feeding pipe with a feeding motor and a mixing chamber with a stirring motor. The mixing chamber has a feeding port in the middle and a discharge valve at the bottom. When the discharge valve is open, the mixing chamber is connected to the front end of the feeding pipe, and the end of the feeding pipe is connected to the feeding end of the roasting kiln. The center of the discharge end of the roasting kiln and the center of the discharge port are on the same vertical line. The roasting kiln has an air outlet connected to a dust removal system. The roasting kiln is fixedly installed on the lifting platform. The water immersion tank has a water inlet, a roasting product inlet, and a variable frequency speed control motor stirring paddle at the top. The bottom of the water immersion tank has a low-impurity rare earth water immersion liquid outlet. A detachable filter screen is installed above the low-impurity rare earth water immersion liquid outlet to collect water immersion residue. At the same time, the detachable filter screen is lower than the stirring trajectory of the stirring paddle. An acid leaching tank is provided with an acid inlet and a water leaching residue inlet at the top, and a high-quality solution outlet at the bottom. A detachable filter screen is provided above the high-quality solution outlet for collecting the high-quality leaching residue. The deep dissolving tank has an acid inlet and a slag inlet at the top, a deep solution outlet at the bottom, and a removable filter screen above the deep solution outlet for collecting the slag.

11. The process apparatus for roasting ion-adsorption rare earth ores with ammonium chloride according to claim 10, characterized in that, The dust removal facility includes a two-stage water suction device, and the air outlet is connected to the two-stage water suction device via an exhaust gas delivery pipeline.

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