Method for mechanically activating, intensifying and decomposing mineral type rare earth ore and smelting and separating

Abstract

The invention discloses a method for mechanically activating and intensifying decomposition of mineral type rare earth ore and smelting separation, which comprises the following steps of: S1, adding the mineral type rare earth ore serving as a raw material into ore grinding equipment, and mechanically activating under the action of microwaves; s2, mixing the mechanically activated mineral type rare earth ore obtained in the step S1 with concentrated sulfuric acid, performing sulfating roasting decomposition to obtain sulfating roasted ore, and treating tail gas generated by roasting; and S3, the sulfated roasted ore obtained in the step S2 is leached through a magnesium bicarbonate solution, neutralization and impurity removal are conducted, and after solid-liquid separation is conducted, a sulfuric acid rare earth solution and leaching residues are obtained. The mineral type rare earth ore is subjected to mechanical and microwave activation treatment, so that the granularity of mineral particles is reduced, generation of a new reaction surface is promoted, a mineral crystal structure is deformed, a rare earth phase is subjected to favorable change, wrapped rare earth mineral components are fully exposed and are fully contacted and reacted with acid, and the activation performance of the rare earth ore is improved; and a higher rare earth yield is obtained.

Description

Technical Field

[0001] This invention relates to the field of rare earth metallurgy technology, and in particular to a method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them. Background Technology

[0002] Mineral-type rare earth ores mainly include bastnaesite, monazite, xenotime, and mixed rare earth ores. Baotou mixed rare earth ore is a mixture of mineral-type rare earth and monazite. Currently, the mainstream processing technology uses concentrated sulfuric acid roasting at temperatures between 300℃ and 800℃. At this temperature, the sulfation roasting process of rare earth concentrate can convert thorium into thorium pyrophosphate, which is fixed in the slag, facilitating low-cost and safe storage, while avoiding the problem of high residual acid content in low-temperature sulfuric acid roasting. However, at high temperatures, the decomposition of concentrated sulfuric acid produces a mixed tail gas of SO3 / SO2 / HF / SiF4. Currently, the mainstream industrial method uses water spray absorption to absorb the SO3 / HF / SiF4 in the mixed tail gas, converting it into a mixed acid of sulfuric acid and fluorosilicic acid. The SO2 gas is further catalytically oxidized to SO3, ultimately converting into a high-concentration sulfuric acid product. However, the sulfuric acid and fluorosilicic acid produced during the mixed tail gas treatment process cannot be used as products, and separation costs are high. Using lime neutralization would result in resource waste and could easily cause secondary environmental pollution.

[0003] Fluorocarbon cerium ore is my country's second largest rare earth resource. Currently, the conventional industrial processing technology for mineral-type rare earth ores is oxidative roasting-acid leaching-alkali dissolution. The advantages of this process are low investment and no sulfur-containing waste gas generation, but it has the following problems: (1) alternating use of hydrochloric acid and liquid alkali; (2) intermittent process with many steps: the alkali conversion process is difficult to wash (NaF has low solubility, 12 washing steps, large amount of washing water), and the addition of a large amount of flocculant affects subsequent extraction; (3) the impurity removal process is complicated, requiring step-by-step removal of thorium, fluorine, barium, and lead; (4) low rare earth yield. During the oxidative roasting process, cerium in the mineral-type rare earth ore is converted into CeO2, which is not easily dissolved during the leaching process. 90% of Ce is converted into cerium-enriched products, with a total emission >10 6 Bq / g, cannot be sold; 10% Ce is converted into cerium oxide and other products, with a purity of only about 98%, and has a low market value; (5) In addition to process loss, praseodymium and neodymium lose 1 to 2 percentage points and enter cerium enrichment; (6) Mineral beneficiation requires iron removal, and the grade of rare earth concentrate is required to be high.

[0004] Besides sulfuric acid roasting, alkaline decomposition can also be used to process mineral-type rare earth ores. This involves converting the mineral-type rare earth ore into RE(OH)3 at 150℃–300℃ using NaOH, followed by acid leaching of the rare earth elements. This method effectively recovers rare earth elements from mineral-type rare earth ores without generating waste gas. However, alkaline decomposition of mineral-type rare earth ores consumes large amounts of acid and alkali and produces a large amount of saline wastewater, which is difficult to treat to meet standards and incurs high environmental costs.

[0005] Due to different beneficiation processes, the particle size of mineral-type rare earth ores obtained by gravity separation, magnetic separation, and flotation varies considerably. Among them, the particle size of gravity separation concentrate is relatively coarse (D90>95μm). When using the sulfation roasting method to process mineral-type rare earth ores, there is a problem of insufficient dissociation or exposure of the mineral-type rare earth ores. Therefore, concentrated sulfuric acid is difficult to contact some mineral-type rare earth ores, and the sulfation acid decomposition is not fully carried out. In addition, there is a problem that newly generated calcium sulfate encapsulates the mineral particles, causing the reaction to stagnate. During water leaching, rare earth elements cannot enter the liquid phase, thus reducing the recovery rate of rare earth elements.

[0006] Furthermore, the smelting, separation, and purification of rare earth elements generally employ solvent extraction. Traditional rare earth smelting processes use ammonia or sodium hydroxide to saponify organic extractants, removing hydrogen ions through displacement, followed by exchange extraction and separation with rare earth ions. However, this extraction process consumes large amounts of liquid ammonia or liquid alkali, increasing costs and generating significant amounts of ammonia nitrogen wastewater or high-sodium wastewater.

[0007] After extraction and separation, rare earth leachate yields a single or mixed rare earth chloride solution, which is then precipitated using oxalic acid or ammonium bicarbonate, followed by calcination to produce rare earth oxides. However, oxalic acid is expensive, leading to high production costs, and the production process generates large amounts of wastewater, causing serious environmental pollution. Ammonium bicarbonate is relatively inexpensive, but its production process generates large amounts of carbon dioxide and high-concentration ammonium salt wastewater, and its production cycle is long, making product quality control difficult. Summary of the Invention

[0008] The purpose of this invention is to provide a method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them. The method involves mechanically and microwave activating the mineral-type rare earth ores and then subjecting them to sulfuric acid-enhanced roasting. Magnesium sulfate wastewater and carbon dioxide generated during the smelting and separation process are recycled to prepare magnesium bicarbonate solution for leaching and saponifying organic extractants. Combined with electrolysis to treat the rare earth chloride solution obtained from the extraction transformation and extraction separation, the method achieves the recycling of magnesium, carbon dioxide, water, and hydrochloric acid during the rare earth ore smelting and separation process, thus realizing zero-waste production.

[0009] To address the aforementioned technical problems, embodiments of the present invention provide a method for mechanically activating and enhancing the decomposition of mineral-type rare earth ores and for smelting and separating them, comprising the following steps:

[0010] S1: Using mineral-type rare earth ore as raw material, the raw material is added into the grinding equipment and mechanically activated under microwave action;

[0011] S2: The obtained mechanically activated mineral rare earth ore is mixed with a certain proportion of concentrated sulfuric acid and then subjected to sulfation roasting decomposition to obtain sulfation roasted ore. The tail gas generated during roasting is then treated.

[0012] S3: The obtained sulfated roasted ore is leached with magnesium bicarbonate solution, neutralized to remove impurities, and then separated into solid and liquid components to obtain rare earth sulfate solution and leaching residue.

[0013] Furthermore, the rare earth solution obtained in step S3 is subjected to extraction transformation or extraction separation using an organic extractant to obtain a single or mixed rare earth chloride solution.

[0014] Furthermore, the single or mixed rare earth chloride solution is subjected to ion-exchange membrane electrolysis to obtain rare earth hydroxide or rare earth oxide products and hydrogen gas at the cathode, and to generate chlorine gas at the anode.

[0015] Furthermore, during the electrolysis process, carbon dioxide is introduced into the cathode to obtain rare earth carbonate products.

[0016] Furthermore, the mineral-type rare earth minerals include one or more of the following: bastnaesite, monazite, xenotime, and mixed rare earth minerals.

[0017] Furthermore, the frequency of the microwave is 2000–3000 MHz.

[0018] Furthermore, the particle size after mechanical activation is D90 < 50 μm and D50 < 18 μm.

[0019] Furthermore, the concentration of concentrated sulfuric acid used in the sulfation roasting decomposition is greater than 90 wt%, the mass ratio of the concentrated sulfuric acid to the mineral-type rare earth ore is 1.0 to 2.0, the sulfation roasting temperature is 150 to 400°C, and the roasting time is 1.0 to 8.0 h.

[0020] Preferably, the mass ratio of concentrated sulfuric acid to mineral-type rare earth ore is 1.2 to 1.5, the roasting temperature is 180 to 350°C, and the roasting time is 2.0 to 5.0 h.

[0021] Furthermore, the exhaust gas generated during roasting contains SO2, SO3, HF, and SiF4, which are absorbed by water spray, distilled, and separated to recover sulfuric acid and fluorine-containing products.

[0022] Furthermore, the rare earth content in the sulfuric acid rare earth solution, calculated as REO, is 10–45 g / L.

[0023] Furthermore, the preparation process of the magnesium bicarbonate solution includes the following steps:

[0024] Step A: The pH of the magnesium sulfate wastewater generated from rare earth extraction and separation is adjusted to 10.0-12.5 using a calcium-containing alkaline substance to obtain a slurry containing magnesium hydroxide and calcium sulfate.

[0025] Step B involves carbonizing the slurry containing magnesium hydroxide and calcium sulfate using CO2, followed by solid-liquid separation to obtain a magnesium bicarbonate solution and a calcium sulfate byproduct.

[0026] Furthermore, the concentration of the magnesium bicarbonate solution, calculated as MgO, is 5–15 g / L.

[0027] Furthermore, the organic extractant used in the extraction transformation or extraction separation process is P507 and / or P204 saponified with magnesium bicarbonate solution;

[0028] The rare earth content in the single or mixed rare earth chloride solution is 200-300 g / L.

[0029] Furthermore, during the electrolysis process, an ion exchange membrane is used to divide the electrolytic cell into a cathode chamber and an anode chamber; the current density is 500 A / m³. 2 ~8000A / m 2 The tank voltage is 2V to 5V.

[0030] Furthermore, the rare earth product is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

[0031] Furthermore, the hydrogen and chlorine are used to prepare hydrochloric acid, which is then reused in the extraction transformation, extraction separation process, organic phase washing, and back-extraction.

[0032] The above-described technical solutions of the embodiments of the present invention have the following beneficial technical effects:

[0033] 1. By mechanically and microwaveally activating mineral-type rare earth ores, the particle size of the minerals is reduced, the formation of new reaction surfaces is promoted, the crystal structure of the minerals is deformed, and the rare earth phases undergo favorable changes. This helps to fully expose the encapsulated rare earth mineral components, making them easier to contact and react with acids, thereby improving their activation performance and achieving a higher rare earth yield.

[0034] 2. After mechanical and microwave activation, the mineral-type rare earth ore is subjected to sulfation roasting, in which all rare earth elements in the mineral-type rare earth ore are converted into the easily leached phase RE2(SO4)3, which shortens the processing flow and reduces the processing time, and helps to improve the rare earth yield.

[0035] 3. Magnesium sulfate wastewater and carbon dioxide generated during rare earth separation are used to prepare magnesium bicarbonate solution, which is used for rare earth leaching and saponification of organics, thus realizing the recycling of water, magnesium and carbon dioxide; rare earth chloride solution is electrolyzed to prepare rare earth oxide products, and the by-products hydrogen and chlorine are used to prepare hydrochloric acid and reused in the extraction process, thus achieving zero-waste production.

[0036] 4. This invention solves the problem of ammonia nitrogen and high-salt wastewater discharge in the rare earth smelting and separation process from the source, and realizes resource recycling. Attached Figure Description

[0037] Figure 1 This is a flowchart of the method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them, provided in an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the mechanical activation and enhanced decomposition of mineral-type rare earth ore and the smelting and separation process provided in the embodiments of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0040] Please refer to Figure 1 and Figure 2 This invention provides a method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them, comprising the following steps:

[0041] Step S1: Using mineral-type rare earth ore as raw material, the raw material is added to the grinding equipment and mechanically activated under microwave action.

[0042] Mechanical activation utilizes mechanical actions such as grinding, compression, shearing, and impact to alter the physical properties of mineral particles and disrupt their crystal structure. Mechanical grinding not only changes the macroscopic morphology, particle size, and specific surface area of ​​mineral particles but also disrupts their crystal structure, such as causing lattice distortion and increased disorder, thereby enhancing their activation performance and reducing the requirements for reaction conditions such as temperature and solution dosage. The mechanical energy input through mechanical force can induce some chemical reactions that cannot be induced by heat energy, and the reaction conditions and processes are easily achieved, thus effectively addressing energy and resource conservation issues.

[0043] Microwaves enable efficient and rapid heating and are widely used in chemical and mineral processing fields. They help accelerate chemical reaction rates and change product properties. Mechanical activation under microwave action can cause mineral components to vibrate rapidly. Due to the different microwave absorption capabilities of minerals, the heating rates are different. Cracks are generated between different minerals due to thermal stress, thereby exposing the encapsulated and impregnated minerals and changing the specific surface area and pore structure of mineral particles, thus improving the reactivity.

[0044] By mechanically and microwaveally activating mineral-type rare earth ores, the particle size of the minerals is reduced, the formation of new reaction surfaces is promoted, the mineral crystal structure is deformed, and the rare earth phase undergoes favorable changes. This helps to fully expose the encapsulated rare earth mineral components, making them easier to contact and react with acids, thereby improving their activation performance and achieving a higher rare earth yield.

[0045] Step S2: The obtained mechanically activated mineral rare earth ore is mixed with a certain proportion of concentrated sulfuric acid and then subjected to sulfation roasting decomposition to obtain sulfated roasted ore. The tail gas generated during roasting is then treated.

[0046] Step S3: The obtained sulfated roasted ore is leached with magnesium bicarbonate solution, neutralized to remove impurities, and then separated into solid and liquid components to obtain rare earth sulfate solution and leaching residue.

[0047] Furthermore, the rare earth solution obtained in step S3 is subjected to extraction transformation or extraction separation using an organic extractant to obtain a single or mixed rare earth chloride solution.

[0048] Furthermore, the single or mixed rare earth chloride solution is subjected to ion-exchange membrane electrolysis to obtain rare earth hydroxide or rare earth oxide products and hydrogen gas at the cathode, and to generate chlorine gas at the anode.

[0049] Furthermore, during the electrolysis process, carbon dioxide is introduced into the cathode to obtain rare earth carbonate products.

[0050] Furthermore, the mineral-type rare earth minerals include one or more of the following: bastnaesite, monazite, xenotime, and mixed rare earth minerals.

[0051] Furthermore, the frequency of the microwave is 2000–3000 MHz.

[0052] Within the specified frequency range, rapid heating of the raw materials helps to quickly generate cracks in the mineral-type rare earth mineral particles and change their crystal structure, thereby exposing the encapsulated and impregnated minerals and improving their reactivity.

[0053] Furthermore, the particle size after mechanical activation is D90 < 50 μm and D50 < 18 μm.

[0054] Mechanically activating mineral-type rare earth ores to the specified particle size range helps to fully expose the mineral components, facilitating subsequent sulfation roasting and decomposition, and improving the rare earth yield.

[0055] Furthermore, the concentration of concentrated sulfuric acid used in the sulfation roasting decomposition is greater than 90 wt%, the mass ratio of the concentrated sulfuric acid to the mineral-type rare earth ore is 1.0 to 2.0, the sulfation roasting temperature is 150 to 400°C, and the roasting time is 1.0 to 8.0 h.

[0056] Preferably, the mass ratio of concentrated sulfuric acid to mineral-type rare earth ore is 1.2 to 1.5, the roasting temperature is 180 to 350°C, and the roasting time is 2.0 to 5.0 h.

[0057] Within the specified mass ratio of concentrated sulfuric acid to mineral-type rare earth ore, roasting temperature, and roasting time, the mineral components can fully react with sulfuric acid and be converted into rare earth sulfate. Within the specified preferred conditions, the reaction efficiency can be improved more effectively, sulfuric acid decomposition can be reduced, and energy consumption can be reduced, thereby effectively reducing production costs.

[0058] Furthermore, the exhaust gas generated during roasting contains SO2, SO3, HF, and SiF4, which are absorbed by water spray, distilled, and separated to recover sulfuric acid and fluorine-containing products.

[0059] Furthermore, the rare earth content in the sulfuric acid rare earth solution, calculated as REO, is 10–45 g / L.

[0060] Within the specified rare earth sulfate concentration range, sufficient leaching of rare earth sulfate can be ensured, thereby guaranteeing the rare earth yield.

[0061] Furthermore, the preparation process of the magnesium bicarbonate solution includes the following steps:

[0062] Step A: The pH of the magnesium sulfate wastewater generated from rare earth extraction and separation is adjusted to 10.0-12.5 using a calcium-containing alkaline substance to obtain a slurry containing magnesium hydroxide and calcium sulfate.

[0063] Step B involves carbonizing the slurry containing magnesium hydroxide and calcium sulfate using CO2, followed by solid-liquid separation to obtain a magnesium bicarbonate solution and a calcium sulfate byproduct.

[0064] Within the specified pH range, it can be ensured that calcium-containing alkaline substances can more fully convert magnesium sulfate into magnesium hydroxide and calcium sulfate, avoiding incomplete reactions that could lead to unstable concentrations.

[0065] Furthermore, the concentration of the magnesium bicarbonate solution, calculated as MgO, is 5–15 g / L.

[0066] Within the specified concentration range of magnesium bicarbonate solution, magnesium bicarbonate can be made more stable and can fully react with organic extractants under the corresponding concentration conditions, reducing resource waste.

[0067] Furthermore, the organic extractant used in the extraction transformation or extraction separation process is P507 and / or P204 saponified with magnesium bicarbonate solution;

[0068] The rare earth content in the single or mixed rare earth chloride solution is 200-300 g / L.

[0069] Furthermore, during the electrolysis process, an ion exchange membrane is used to divide the electrolytic cell into a cathode chamber and an anode chamber; the current density is 500 A / m³. 2 ~8000A / m 2 The tank voltage is 2V to 5V.

[0070] Within the specified current density and cell voltage range, efficient electrolysis of rare earth chloride solution can be achieved, avoiding side reactions that could affect product quality. At the same time, the electrolysis reaction can be carried out at a lower power consumption, thereby reducing production costs and saving energy.

[0071] Furthermore, the rare earth product is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

[0072] Furthermore, the hydrogen and chlorine are used to prepare hydrochloric acid, which is then reused in the extraction transformation, extraction separation process, organic phase washing, and back-extraction.

[0073] The rare earth chloride solution obtained through extraction and separation is electrolyzed to produce hydrogen and chlorine, which are then used to prepare hydrochloric acid. This process enables the recycling of hydrochloric acid during extraction, eliminates the discharge of salt-containing wastewater during production, and saves resources.

[0074] The following is a detailed description of the above-mentioned method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them, using a complete implementation process:

[0075] (1) Add mineral-type rare earth ore to the grinding equipment and mechanically activate it under the action of microwave at 2000-3000MHz until the particle size reaches D90<50μm and D50<18μm. Then, perform sulfation roasting decomposition to obtain sulfation roasted ore.

[0076] (2) The concentration of concentrated sulfuric acid used is greater than 90wt%, the amount of concentrated sulfuric acid used is 1.2 to 1.5 times the mass of mineral rare earth ore, the temperature of sulfation roasting is 180 to 350℃, and the roasting time is 2.0 to 5.0h; all rare earth elements in mineral rare earth ore are converted into easily leached phase RE2(SO4)3.

[0077] (3) The sulfated roasted ore is leached with a magnesium bicarbonate solution with a concentration of 5-15 g / L, neutralized to remove impurities, and separated into solid and liquid to obtain a rare earth sulfate solution and leaching residue.

[0078] (4) The mixed tail gas generated during the sulfation roasting process is treated by the tail gas absorption system to obtain concentrated sulfuric acid and fluorosilicic acid products with a concentration greater than 90wt%.

[0079] (5) The rare earth sulfate solution is extracted and / or separated by using P507 and / or P204 saponified with magnesium bicarbonate at a concentration of 5-15 g / L to obtain a rare earth chloride solution with a concentration of 200-300 g / L.

[0080] (6) The rare earth chloride solution is subjected to a current density of 500–8000 A / m 2 Electrolysis is performed under a cell voltage of 2-5V to obtain rare earth hydroxide or rare earth oxide products; or carbon dioxide is introduced into the cathode to obtain rare earth carbonate products.

[0081] (7) The magnesium sulfate wastewater generated during the extraction separation and / or extraction conversion process is subjected to alkaline conversion using a calcium-containing alkaline substance to obtain a slurry containing magnesium hydroxide and calcium sulfate. The slurry containing magnesium hydroxide and calcium sulfate is then carbonized using CO2 recovered from the smelting separation process. After solid-liquid separation, a magnesium bicarbonate solution with a concentration of 5–15 g / L and calcium sulfate slag are obtained. The following comparative examples and embodiments further illustrate the process flow and technical effects of the present invention:

[0082] Example 1

[0083] 1000g of bastnaesite was added to a ball mill and mechanically activated under microwave irradiation at a frequency of 2450MHz. The activated bastnaesite had particle sizes of D50 < 10μm and D90 < 30μm. It was mixed with 1200g of concentrated sulfuric acid (98wt%) and placed in a roasting kiln for roasting at 150℃ for 3 hours. Leaching was performed using 38L of water and 2.4L of a 6.5g / L (calculated as MgO) magnesium bicarbonate solution, followed by acid adjustment. The rare earth leaching rate was 94.9%. P507 was saponified using the 6.5g / L magnesium bicarbonate solution. The saponified organic compound was then used for extraction and separation of rare earth sulfate solution to obtain a 280g / L rare earth chloride solution. The solution was then processed at a current density of 1000A / m². 2 Electrolysis was performed at a cell voltage of 2V. The rare earth hydroxide produced after electrolysis was filtered, washed, dried, and calcined to obtain rare earth oxide products. The total rare earth yield was 93.0%. The hydrogen gas generated at the cathode and the chlorine gas generated at the anode were collected and prepared into 31% hydrochloric acid, which was used for washing and back-extracting the supported organic matter.

[0084] Example 2

[0085] 1000g of bastnaesite was added to a ball mill and mechanically activated under microwave irradiation at a frequency of 2450MHz. The activated mixed rare earth ore had particle sizes of D50 < 18μm and D90 < 50μm. This was mixed with 1500g of concentrated sulfuric acid (98wt%) and placed in a roasting kiln for 1 hour at 400℃. Leaching was then performed using 36L of water and 4.3L of a 6.5g / L magnesium bicarbonate solution, followed by acid adjustment. The rare earth leaching rate was 93.2%. P507 was saponified using the 6.5g / L magnesium bicarbonate solution. The saponified organic compound was then used for extraction and separation from the rare earth sulfate solution, yielding a 280g / L rare earth chloride solution. The solution was then processed at a current density of 4000A / m³. 2 Electrolysis was performed at a cell voltage of 3V, with carbon dioxide gas introduced at the cathode. The rare earth carbonate produced after electrolysis was filtered, washed, dried, and calcined to obtain rare earth oxide products. The total rare earth yield was 91.1%. The hydrogen gas generated at the cathode and the chlorine gas generated at the anode were collected and prepared into 31% hydrochloric acid, which was used for washing and back-extracting the supported organic matter.

[0086] Example 3

[0087] 1000g of xenotime ore was added to a ball mill and mechanically activated under microwave irradiation at a frequency of 2450MHz. The activated xenotime ore had a particle size of D50 < 5μm and D90 < 10μm. It was mixed with 1400g of concentrated sulfuric acid (98wt%) and placed in a roasting kiln. Roasting was carried out at 200℃ for 2 hours. Leaching was performed using 37L of water and 3.7L of a 6.5g / L magnesium bicarbonate solution, followed by acid adjustment. The rare earth recovery rate was 95.1%. P507 was saponified using the 6.5g / L magnesium bicarbonate solution. Extraction and separation were then performed using the saponified organic solvent to obtain a 280g / L rare earth chloride solution. The solution was then processed at 75℃ and a current density of 6000A / m. 2 Electrolysis was performed at a cell voltage of 4V. The precipitate produced after electrolysis was filtered, washed, dried, and calcined to obtain rare earth oxide products. The total rare earth yield was 92.9%. Hydrogen gas generated at the cathode and chlorine gas generated at the anode were collected and prepared into 31% hydrochloric acid, which was used for washing and back-extracting the loaded organic matter.

[0088] Detailed implementation data for Examples 1-31 are shown in Table 1.

[0089] Table 1

[0090]

[0091]

[0092] Based on the above 31 embodiments of the present invention, the following conclusions can be drawn:

[0093] This invention reduces the particle size of mineral rare earth ores by mechanically and microwave activating them, promotes the formation of new reaction surfaces, deforms the mineral crystal structure, and causes favorable changes in the rare earth phases. This helps to fully expose the encapsulated rare earth mineral components, making them easier to contact and react with acids, thereby improving their activation performance and achieving a higher rare earth yield.

[0094] The method described in this invention for processing fluorocarbon cerium rare earth concentrate can effectively shorten the process flow and reduce processing time. While ensuring a high rare earth yield, it effectively reduces the amount of acid and alkali used, thereby significantly reducing production costs. The washing water is used for hydrochloric acid dilution, which can ensure an increased rare earth yield and effectively reduce wastewater discharge.

[0095] This invention aims to protect a method for mechanically activating and enhancing the decomposition of mineral-type rare earth ores and for smelting and separating them, comprising the following steps: S1: Using mineral-type rare earth ores as raw material, the raw material is added to a grinding equipment and mechanically activated under microwave action; S2: The mechanically activated mineral-type rare earth ores obtained in step S1 are mixed with concentrated sulfuric acid and then subjected to sulfation roasting decomposition to obtain sulfated roasted ore, and the tail gas generated during roasting is treated; S3: The sulfated roasted ore obtained in step S2 is leached with magnesium bicarbonate solution, neutralized to remove impurities, and subjected to solid-liquid separation to obtain rare earth sulfate solution and leaching residue. The above technical solution has the following effects:

[0096] By mechanically and microwaveally activating mineral-type rare earth ores, the particle size of the minerals is reduced, the formation of new reaction surfaces is promoted, the crystal structure of the minerals is deformed, and the rare earth phases undergo favorable changes. This helps to fully expose the encapsulated rare earth mineral components, making them easier to contact and react with acids, thereby improving their activation performance and achieving a higher rare earth yield.

[0097] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for mechanically activating and enhancing the decomposition of mineral-type rare earth ores and for smelting and separating them, characterized in that, The steps include: S1: Using mineral-type rare earth ore as raw material, the raw material is added into the grinding equipment and mechanically activated under microwave action; S2: The mechanically activated mineral rare earth ore obtained in step S1 is mixed with concentrated sulfuric acid and then subjected to sulfation roasting decomposition to obtain sulfation roasted ore. The tail gas generated during roasting is then treated. S3: The sulfated roasted ore obtained in step S2 is leached with magnesium bicarbonate solution, neutralized to remove impurities, and then separated into solid and liquid components to obtain rare earth sulfate solution and leaching residue.

2. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The rare earth solution obtained in step S3 is subjected to extraction transformation or extraction separation using an organic extractant to obtain a single or mixed rare earth chloride solution.

3. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 2, characterized in that, The single or mixed rare earth chloride solution is subjected to ion-exchange membrane electrolysis to obtain rare earth hydroxide or rare earth oxide products and hydrogen gas at the cathode, and to generate chlorine gas at the anode.

4. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 3, characterized in that, During the electrolysis process, carbon dioxide is introduced into the cathode to obtain rare earth carbonate products.

5. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The mineral-type rare earth minerals include one or more of the following: bastnaesite, monazite, xenotime, and mixed rare earth minerals.

6. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The frequency of the microwave is 2000–3000 MHz.

7. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The mechanically activated particles have a particle size of D90 < 50 μm and D50 < 18 μm.

8. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The concentration of concentrated sulfuric acid used in the sulfation roasting decomposition is greater than 90 wt%, the mass ratio of the concentrated sulfuric acid to the mineral-type rare earth ore is 1.0 to 2.0, the sulfation roasting temperature is 150 to 400℃, and the roasting time is 1.0 to 8.0 h. Preferably, the mass ratio of concentrated sulfuric acid to mineral-type rare earth ore is 1.2 to 1.5, the roasting temperature is 180 to 350°C, and the roasting time is 2.0 to 5.0 h.

9. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The exhaust gas generated during roasting contains SO2, SO3, HF and SiF4, which is absorbed by water spray, distilled and separated to recover sulfuric acid and fluorine-containing products.

10. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The rare earth content in the sulfuric acid rare earth solution, calculated as REO, is 10–45 g / L.

11. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The preparation process of the magnesium bicarbonate solution includes the following steps: Step A: The pH of the magnesium sulfate wastewater generated from rare earth extraction and separation is adjusted to 10.0-12.5 using a calcium-containing alkaline substance to obtain a slurry containing magnesium hydroxide and calcium sulfate. Step B involves carbonizing the slurry containing magnesium hydroxide and calcium sulfate using CO2, followed by solid-liquid separation to obtain a magnesium bicarbonate solution and a calcium sulfate byproduct.

12. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 11, characterized in that, The concentration of the magnesium bicarbonate solution, calculated as MgO, is 5–15 g / L.

13. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 2, characterized in that, The organic extractant used in the extraction transformation or extraction separation process is P507 and / or P204 saponified with magnesium bicarbonate solution. The rare earth content in the single or mixed rare earth chloride solution is 200-300 g / L.

14. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 3, characterized in that, During the electrolysis process, an ion exchange membrane is used to divide the electrolytic cell into a cathode chamber and an anode chamber; the current density is 500 A / m. 2 ~8000A / m 2 The tank voltage is 2V to 5V.

15. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 1, characterized in that, The rare earth product is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

16. The method for mechanically activating and strengthening the decomposition of mineral-type rare earth ores and for smelting and separating them according to claim 3, characterized in that, The hydrogen and chlorine are used to prepare hydrochloric acid, which is then reused in extraction transformation, organic phase washing, and back-extraction during extraction separation processes.

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