Method for separating zirconium and hafnium in zirconite

Abstract

The invention relates to the technical field of mineral processing, and discloses a method for separating zirconium and hafnium in zirconite, which comprises the following steps: pretreating raw materials, crushing the zirconite raw materials into particles with the particle size of 0.5-5mm through a jaw crusher, obtaining particles with uniform particle size through vibrating screening equipment, and then separating zirconium and hafnium in the zirconite by adopting a mineral separation and purification technology combining gravity separation, magnetic separation and electric separation to obtain zirconium and hafnium in the zirconite. Gangue and iron-titanium impurities are removed according to density, magnetism and electrical property differences; and chlorination reaction: mixing the pretreated zirconite and carbon according to the mass ratio of 1: 0.8, putting the mixture into a high-temperature chlorination furnace, carrying out chlorination for 4 hours at the temperature of 850-1100 DEG C to generate (Zr, Hf) Cl4 mixed gas, and collecting and purifying the gas through a condensation and washing device to ensure the purity of the zirconium-hafnium chloride in the gas. The method for separating the zirconium and the hafnium in the zirconite aims at solving the problems of low separation efficiency, high cost and serious environmental pollution generally existing in a traditional zirconium and hafnium separation method.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, in particular to a method for separating zirconium and hafnium from zircon. Background Art

[0002] Zirconium and hafnium are precious rare metals in the earth's crust. They often exist together in zircon minerals. These two metals have their own characteristics and have demonstrated irreplaceable value in many fields. Zirconium is famous for its excellent corrosion resistance and extremely low thermal neutron absorption cross-section. This feature makes it occupy a pivotal position in the nuclear industry. In the construction and operation of nuclear reactors, zirconium can resist the erosion of radiation and high temperature to ensure the safe and stable operation of the reactor. In contrast, hafnium is known for its high thermal neutron absorption cross-section. This unique property makes hafnium a key material for nuclear submarine reactor control rods. By precisely controlling the content and distribution of hafnium, the reactor neutron flow can be effectively regulated, thereby ensuring that the nuclear submarine's power system is both powerful and reliable.

[0003] Traditional zirconium and hafnium separation often uses hydrometallurgical processes such as solvent extraction, step-by-step crystallization and ion exchange. Although in theory, it can achieve effective separation of zirconium and hafnium, it faces the problem of low separation efficiency in actual operation. These processes often require complex processes and a large amount of chemical reagents, resulting in high production costs. In addition, wastewater, waste slag and other wastes generated during the hydrometallurgical process, if not properly handled, can easily cause serious pollution to the environment. Although the pyrometallurgical process simplifies the separation process to a certain extent, its high energy consumption and pollution are also prominent. Under high temperature conditions, zirconium and hafnium are prone to chemical reactions with other impurity elements, resulting in difficulty in ensuring separation purity, and there are certain defects. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of low separation efficiency, high cost and serious environmental pollution commonly existing in traditional zirconium and hafnium separation methods, and to propose a method for separating zirconium and hafnium in zircon.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A method for separating zirconium and hafnium from zircon comprises the following steps:

[0007] S10, raw material pretreatment, the zircon raw material is crushed into a particle size of 0.5mm to 5mm by a jaw crusher, and the particles with uniform particle size are obtained by a vibration screening device, and then the ore dressing and purification technology combining gravity separation, magnetic separation and electric separation is used to remove gangue and iron-titanium impurities according to the differences in density, magnetism and electrical properties;

[0008] S20, chlorination reaction, mixing the pretreated zircon with carbon in a mass ratio of 1:0.8, placing in a high-temperature chlorination furnace, chlorinating at a temperature of 850° C. to 1100° C. for 4 hours to generate a (Zr, Hf)Cl4 mixed gas, and collecting and purifying the gas through a condensation and washing device to ensure the purity of zirconium and hafnium chloride in the gas;

[0009] S30, solvent extraction and ion exchange combined separation, using the improved MIBK-SCN system as the extractant, through the countercurrent extraction process, according to the difference in the distribution coefficient of Zr and Hf in the extractant, to achieve preliminary separation, then use macroporous cationic adsorption resin for ion exchange, further according to the different adsorption capacity of Zr and Hf on the resin, to achieve the purpose of efficient separation;

[0010] S40, product preparation, the separated ZrCl4 and HfCl4 are subjected to multi-stage distillation purification to remove trace impurities; then, under the protection of inert gas, a magnesium thermal reduction method is used to carry out a reduction reaction at 700°C to obtain sponge zirconium and sponge hafnium; finally, residual chloride and metallic magnesium are removed by vacuum distillation, and after crushing, a zirconium and hafnium product with uniform particle size is obtained.

[0011] Based on the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, in the raw material pretreatment step of step S10, the operating speed of the jaw crusher is set to 300 revolutions per minute, and the vibrating screening equipment adopts a 20-mesh to 100-mesh screen to ensure that the obtained particle size is uniform. In the process of gravity separation, the density difference between the mineral particles in the ore is utilized to separate the mineral particles through the action of the gravity field, wherein the gravity separation adopts one of jigging, shaking table, and chute for sorting, and in the magnetic separation, the magnetic minerals are separated from the non-magnetic minerals under the action of the magnetic field, wherein the magnetic separation equipment used is one of a drum magnetic separator and a disc magnetic separator, and in the process of electric separation, the mineral particles are separated under the action of the electric field, and the separation efficiency can be precisely controlled by adjusting the parameters of the magnetic field strength and the electric field voltage, and the electric separation equipment adopts an electrostatic separator.

[0013] Furthermore, in step S20, an inert gas protection can be introduced into the chlorination furnace, and the reaction formula is 2(Zr,Hf)O2+C+4Cl2→2(Zr,Hf)Cl4+CO2, wherein the inert gas used is nitrogen. When nitrogen is introduced into the chlorination furnace, it should be continuously introduced into the chlorination furnace at a certain flow rate to maintain the stability of the atmosphere in the furnace. At the same time, it is necessary to regularly sample and analyze the gas composition during the chlorination process, and adjust the chlorination temperature and time according to the analysis results to ensure the generation rate and purity of the (Zr,Hf)Cl4 mixed gas.

[0014] Furthermore, in step S30, the volume ratio of the improved MIBK-SCN system extractant is MIBK:SCN=3:1, and the countercurrent extraction stage is set to 5. By precisely controlling the flow rate, temperature and pH value of the extractant, efficient separation of Zr and Hf is achieved, and the formula used is:

[0015]

[0016] KD is the separation coefficient, which is used to quantify the distribution difference between Zr and Hf between the extractant and the aqueous phase, where [Zr] and [Hf] represent the concentrations of zirconium and hafnium in the extractant and the aqueous phase, respectively. The larger the KD value, the greater the distribution difference between Zr and Hf in the extractant, the better the separation effect, and the separation coefficient is greater than 1.5;

[0017] In step S30, the countercurrent extraction process comprises the following steps:

[0018] a1. Preparation stage: ensure that the extraction tower is clean and dry, check and adjust the flow rate control system of the extraction tower to ensure stable and controllable liquid flow, prepare the modified MIBK-SCN system extractant and aqueous solution, wherein the aqueous solution is a solution containing Zr and Hf;

[0019] a2. Loading stage: The extractant is loaded into the upper part of the extraction tower, while the aqueous solution enters from the lower part, ensuring that the extractant and the aqueous solution form a clear interface in the tower to avoid mixing;

[0020] a3. Extraction stage: Turn on the flow rate control system to make the aqueous solution flow upward from the bottom of the extraction tower at a certain flow rate, while the extractant flows downward from the top. During the extraction process, Zr and Hf will gradually transfer from the aqueous phase to the extractant phase according to their distribution coefficient differences in the extractant. The design of the extraction tower should allow the two phases to fully contact to ensure efficient solute transfer;

[0021] a4. Collection stage: collecting the extractant phase rich in Zr and Hf at the top of the extraction tower, and collecting the aqueous phase solution from which most of the Zr and Hf have been removed at the bottom of the extraction tower;

[0022] a5. Post-treatment stage: The collected extractant phase is further treated, washed and stripped to recover Zr and Hf, and the raffinate is properly treated.

[0023] Furthermore, the ion exchange using the macroporous cationic adsorption resin in step S30 specifically includes the following steps:

[0024] b1. Resin pretreatment: Clean the macroporous cationic adsorption resin to remove impurities and unfixed ions, and regenerate the resin with dilute hydrochloric acid to restore its ion exchange capacity;

[0025] b2. Column loading: Load the pretreated resin into the ion exchange column to ensure that the resin layer is uniform and tight;

[0026] b3. Loading: passing the extractant phase containing Zr and Hf obtained after countercurrent extraction through the ion exchange column at a certain flow rate;

[0027] b4. Ion exchange: During the ion exchange process, Zr and Hf will be separated according to their different adsorption capacities on the resin. The ion Hf with stronger adsorption capacity will be preferentially adsorbed by the resin, while the ion Zr with weaker adsorption capacity will remain more in the solution.

[0028] b5. Elution and collection: Use the eluent to pass through the ion exchange column at a certain flow rate to elute the ions adsorbed on the resin, and collect Zr and Hf in the eluate separately for further purification and recovery;

[0029] b6. Resin regeneration and reuse: After completing an ion exchange, the resin is regenerated for reuse.

[0030] Furthermore, in step S30, the model of the macroporous cationic adsorption resin is D001, the resin bed height is 50 cm, the ion exchange flow rate is controlled at 1 BV / h, and the high adsorption capacity of the resin is maintained by adjusting the resin regeneration cycle and the regeneration agent concentration to ensure that the separation efficiency of Zr and Hf is not less than 99%.

[0031] Furthermore, in step S30, hydrochloric acid with a concentration of 3 mol / L is used as the eluent, the elution temperature is 40° C., and the elution time is 2 hours. By precisely controlling the elution conditions, the ZrCl4 and HfCl4 adsorbed on the resin are effectively recovered, and the formula used is:

[0032]

[0033]

[0034] Among them, R represents the recovery rate of ZrCl4, R′ represents the recovery rate of HfCl4, [ZrCl4] recovery liquid and [HfCl4] recovery liquid represent the concentrations of ZrCl4 and HfCl4 in the recovery liquid, respectively, [total ZrCl4] resin adsorption and [total HfCl4] resin adsorption represent the total amount of ZrCl4 and HfCl4 adsorbed by the resin, respectively. The higher the recovery rate, the better the elution effect, and the ZrCl4 and HfCl4 adsorbed by the resin are effectively recovered.

[0035] Furthermore, in step S40, the distillation and purification adopts a multi-stage distillation tower. In step S40, the vacuum distillation equipment adopts a condensing vacuum pump. The conditions of vacuum distillation are vacuum degree 10^-4Pa and temperature 1200°C. The crushing process adopts a hammer crusher and the particle size is controlled between 0.5mm and 2mm.

[0036] Furthermore, the method also includes a pretreatment step of analyzing the chemical composition of the raw materials, using an X-ray fluorescence spectrometer to analyze the content of zirconium, hafnium and major impurities in zircon, and dynamically adjusting the parameters of subsequent processing steps according to the analysis results, such as chlorination temperature, extractant ratio, and ion exchange conditions, to achieve customized production and improve separation efficiency and product quality.

[0037] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0038] The zircon raw material is crushed and screened into particles of uniform size by jaw crusher and vibrating screening equipment. At the same time, the mineral processing and purification technology combining gravity separation, magnetic separation and electrostatic separation can accurately remove impurities such as gangue, iron and titanium based on the differences in density, magnetism and electrical properties, providing high-purity raw materials for subsequent steps, thereby reducing the interference factors in the subsequent separation process at the source and improving the overall separation efficiency. Secondly, by accurately controlling the mass ratio of zircon to carbon and the chlorination temperature and time, a high-purity (Zr, Hf)Cl4 mixed gas is successfully generated. This process not only simplifies the complex process in traditional hydrometallurgical processes, but also avoids the use of a large amount of chemical reagents, thereby reducing production costs and environmental pollution. At the same time, the introduction of condensation and washing devices ensures the purity of zirconium and hafnium chloride in the collected gas, laying a solid foundation for subsequent efficient separation. In the combined separation stage of solvent extraction and ion exchange, the improved MIBK-SCN system is used as the extractant, and the countercurrent extraction process is used. The preliminary separation of Zr and Hf was achieved. Subsequently, ion exchange was performed using macroporous cationic adsorption resin to further improve the separation efficiency. This combined separation method not only fully utilized the differences in the distribution coefficients and adsorption capacities of Zr and Hf on the extractant and resin, but also avoided the cumbersome separation steps and high energy consumption problems in the traditional hydrometallurgical process, and achieved efficient and environmentally friendly separation of zirconium and hafnium. Finally, trace impurities in the separated ZrCl4 and HfCl4 were removed by multi-stage distillation purification to ensure the purity of the product. At the same time, magnesium thermal reduction was used for reduction reaction under the protection of inert gas to obtain sponge zirconium and sponge hafnium. Finally, residual chloride and metallic magnesium were removed by vacuum distillation. After crushing, zirconium and hafnium products with uniform particle size were obtained. This step not only improved the quality and stability of the product, but also met the needs of different fields for zirconium and hafnium materials. In summary, the successful application of this method will provide strong support for the effective utilization of zirconium and hafnium resources and promote scientific and technological progress and development in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of the operating steps of a method for separating zirconium and hafnium from zircon in the present invention;

[0040] Figure 2 The following is a flow chart of the operation steps of the countercurrent extraction process of the present invention;

[0041] Figure 3 The present invention is a flowchart of the operation steps of ion exchange using the macroporous cationic adsorption resin. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Combination Figure 1-Figure 3 As shown, a method for separating zirconium and hafnium from zircon of the present invention comprises the following steps:

[0044] S10, raw material pretreatment, the zircon raw material is crushed into a particle size of 0.5mm to 5mm by a jaw crusher, and the particles with uniform particle size are obtained by a vibration screening device, and then the ore dressing and purification technology combining gravity separation, magnetic separation and electric separation is used to remove gangue and iron-titanium impurities according to the differences in density, magnetism and electrical properties;

[0045] S20, chlorination reaction, mixing the pretreated zircon with carbon in a mass ratio of 1:0.8, placing in a high-temperature chlorination furnace, chlorinating at a temperature of 850° C. to 1100° C. for 4 hours to generate a (Zr, Hf)Cl4 mixed gas, and collecting and purifying the gas through a condensation and washing device to ensure the purity of zirconium and hafnium chloride in the gas;

[0046] S30, solvent extraction and ion exchange combined separation, using the improved MIBK-SCN system as the extractant, through the countercurrent extraction process, according to the difference in the distribution coefficient of Zr and Hf in the extractant, to achieve preliminary separation, then use macroporous cationic adsorption resin for ion exchange, further according to the different adsorption capacity of Zr and Hf on the resin, to achieve the purpose of efficient separation;

[0047] S40, product preparation, the separated ZrCl4 and HfCl4 are subjected to multi-stage distillation purification to remove trace impurities; then, under the protection of inert gas, a magnesium thermal reduction method is used to carry out a reduction reaction at 700°C to obtain sponge zirconium and sponge hafnium; finally, residual chloride and metallic magnesium are removed by vacuum distillation, and after crushing, a zirconium and hafnium product with uniform particle size is obtained.

[0048] In a preferred embodiment, the present invention can be further configured as follows: in the raw material pretreatment step S10, the operating speed of the jaw crusher is set to 300 revolutions per minute, and the vibrating screening equipment uses a 20-mesh to 100-mesh screen to ensure that the obtained particles are uniform in size. In the process of re-selection, the density difference between mineral particles in the ore is utilized to separate the mineral particles through the action of the gravity field, wherein the re-selection is performed by jigging, shaking table, and chute. In the magnetic separation, magnetic minerals are separated from non-magnetic minerals under the action of the magnetic field, wherein the magnetic separation equipment used is one of a drum magnetic separator and a disc magnetic separator. In the process of electrostatic separation, the mineral particles are separated under the action of the electric field, and the separation efficiency can be precisely controlled by adjusting the parameters of the magnetic field strength and the electric field voltage. The electrostatic separation equipment uses an electrostatic separator. In the raw material pretreatment stage, the operating speed of the jaw crusher is precisely set to 300 revolutions per minute, ensuring that the zircon raw material can be uniformly and efficiently crushed to a particle size range of 0.5 mm to 5 mm. At the same time, the use of 20-mesh to 100-mesh vibration screening equipment further ensures the uniformity of the obtained particle size, providing a strong guarantee for the efficient implementation of subsequent steps. In the re-selection process, the present invention utilizes the density difference between mineral particles in the ore and realizes the effective separation of mineral particles through the action of the gravity field. This step not only improves the separation efficiency, but also effectively removes impurities such as gangue with low density. The introduction of magnetic separation and electric separation respectively utilizes the differences in the magnetic and electrical properties of mineral particles to achieve the precise removal of magnetic impurities such as iron and titanium and non-magnetic but charged impurities.

[0049] In the process of gravity separation, one of the various methods such as jigging, shaking table, chute, etc. is used for separation. These methods have their own characteristics. For example, jigging is suitable for processing minerals with relatively uniform particle size, shaking table is more suitable for separating fine-grained minerals, and chute is suitable for processing minerals with less mud content. The most suitable gravity separation method can be selected according to the specific characteristics of the zircon raw material to ensure the maximization of the separation effect. In the magnetic separation process, the present invention adopts one of the drum magnetic separator or the disc magnetic separator. Both of these devices can effectively use the magnetic field to separate magnetic minerals from non-magnetic minerals, but the specific selection depends on the magnetic properties and particle size of the raw material. In the electrostatic separation process, the present invention adopts an electrostatic separator, and by adjusting parameters such as magnetic field strength and electric field voltage, the separation efficiency of mineral particles is precisely controlled. When the content of magnetic impurities such as iron and titanium in the raw material is high, the magnetic field strength can be appropriately increased to improve the magnetic separation efficiency; and when the content of fine-grained minerals in the raw material is high, the electric field voltage can be appropriately increased to enhance the electrostatic separation effect.

[0050] In a preferred embodiment of the present invention, the present invention can be further configured as follows: in step S20, an inert gas protection can be introduced into the chlorination furnace, and the reaction formula is 2(Zr,Hf)O2+C+4Cl2→2(Zr,Hf)Cl4+CO2, wherein the inert gas used is nitrogen. When nitrogen is introduced into the chlorination furnace, it should be continuously introduced into the chlorination furnace at a certain flow rate to maintain the stability of the atmosphere in the furnace. At the same time, during the chlorination process, it is necessary to regularly sample and analyze the gas composition, and adjust the chlorination temperature and time according to the analysis results to ensure the generation rate and purity of the (Zr,Hf)Cl4 mixed gas. By introducing inert gas nitrogen into the chlorination furnace for protection, the interference of impurities such as oxygen on the chlorination reaction is effectively avoided, and the smooth progress of the reaction formula 2(Zr,Hf)O2+C+4Cl2→2(Zr,Hf)Cl4+CO2 is ensured. The continuous introduction of nitrogen not only maintains the stability of the furnace atmosphere, but also effectively reduces the impurity content and improves the purity of the (Zr, Hf)Cl4 mixed gas by replacing the residual air and the gas produced by the reaction in the furnace. In addition, the gas composition is regularly sampled and analyzed during the chlorination process, and the chlorination temperature and time are adjusted according to the analysis results. This measure ensures the precise control of the reaction conditions and further improves the generation rate and purity of the (Zr, Hf)Cl4 mixed gas.

[0051] The nitrogen used as an inert gas not only has the advantages of stable chemical properties and being difficult to react with other substances, but is also easy to obtain and store, thereby reducing production costs. When nitrogen is introduced into the chlorination furnace, it is continuously introduced at a certain flow rate, and this flow rate needs to be accurately calculated according to factors such as the volume of the chlorination furnace, the amount of reactants and the reaction rate to ensure the stability and uniformity of the atmosphere in the furnace. At the same time, the gas composition is regularly sampled and analyzed during the chlorination process, and this step is crucial for monitoring the reaction process and timely adjusting the reaction conditions. When it is detected that the chlorine content in the gas is too high, the amount of chlorine introduced can be appropriately reduced or the chlorination temperature can be increased to promote the complete progress of the reaction; and when it is detected that the oxygen content in the gas is too high, it is necessary to check whether there is leakage in the nitrogen introduction system, and adjust it in time. Through these measures, the present invention realizes accurate control of the chlorination process, and ensures the efficient generation and high purity of the (Zr, Hf)Cl4 mixed gas.

[0052] In a preferred embodiment, the present invention can be further configured as follows: the volume ratio of the improved MIBK-SCN system extractant in step S30 is MIBK:SCN=3:1, the countercurrent extraction stage is set to 5, and the efficient separation of Zr and Hf is achieved by precisely controlling the flow rate, temperature and pH value of the extractant. The formula used is:

[0053]

[0054] KD is the separation coefficient, which is used to quantify the distribution difference between Zr and Hf between the extractant and the aqueous phase, where [Zr] and [Hf] represent the concentrations of zirconium and hafnium in the extractant and the aqueous phase, respectively. The larger the KD value, the greater the distribution difference between Zr and Hf in the extractant, the better the separation effect, and the separation coefficient is greater than 1.5;

[0055] In step S30, the countercurrent extraction process comprises the following steps:

[0056] a1. Preparation stage: ensure that the extraction tower is clean and dry, check and adjust the flow rate control system of the extraction tower to ensure stable and controllable liquid flow, prepare the modified MIBK-SCN system extractant and aqueous solution, wherein the aqueous solution is a solution containing Zr and Hf;

[0057] a2. Loading stage: The extractant is loaded into the upper part of the extraction tower, while the aqueous solution enters from the lower part, ensuring that the extractant and the aqueous solution form a clear interface in the tower to avoid mixing;

[0058] a3. Extraction stage: Turn on the flow rate control system to make the aqueous solution flow upward from the bottom of the extraction tower at a certain flow rate, while the extractant flows downward from the top. During the extraction process, Zr and Hf will gradually transfer from the aqueous phase to the extractant phase according to their distribution coefficient differences in the extractant. The design of the extraction tower should allow the two phases to fully contact to ensure efficient solute transfer;

[0059] a4. Collection stage: collecting the extractant phase rich in Zr and Hf at the top of the extraction tower, and collecting the aqueous phase solution from which most of the Zr and Hf have been removed at the bottom of the extraction tower;

[0060] a5. Post-treatment stage: The collected extractant phase is further treated, washed and stripped to recover Zr and Hf, and the raffinate is properly treated. By precisely adjusting the volume ratio of the MIBK-SCN system extractant to MIBK:SCN=3:1, this optimized ratio not only improves the selectivity of the extractant, but also enhances its extraction capacity for Zr and Hf. At the same time, the countercurrent extraction level is set to 5 levels to ensure the sufficiency and efficiency of the extraction process. By precisely controlling the flow rate, temperature and pH value of the extractant, the extraction process is finely regulated, thereby effectively improving the separation efficiency of Zr and Hf. The introduction of the separation coefficient KD, as an important indicator to quantify the distribution difference between Zr and Hf between the extractant and the aqueous phase, when its value is greater than 1.5, it indicates that the distribution difference between Zr and Hf in the extractant is significant and the separation effect is excellent.

[0061] In the preparation stage, the cleaning and drying of the extraction tower, as well as the inspection and adjustment of the flow control system, are emphasized to ensure the stability and controllability of the extraction process. In the loading stage, the order and method of loading the extractant and the aqueous solution are clarified to avoid mixing of the two phases and ensure the smooth progress of the extraction process. In the extraction stage, the flow mode and contact of the extractant and the aqueous solution in the extraction tower, as well as the design requirements of the extraction tower, are described in detail to ensure the efficient transfer of Zr and Hf. In the collection stage, the collection position and method of the extractant phase and the aqueous solution are clarified to facilitate subsequent treatment and recovery. In the post-treatment stage, the collected extractant phase is further treated, washed and stripped to recover Zr and Hf, and the raffinate is properly treated to maximize resource utilization and environmentally friendly protection. In the extraction stage, the extraction process can be further optimized and the separation efficiency can be improved by adjusting the flow rate of the extractant and the flow rate of the aqueous solution, as well as the design parameters of the extraction tower (such as tower diameter, tower height, filler type, etc.). In the post-treatment stage, appropriate washing agents and stripping agents can be used, and the washing and stripping conditions (such as temperature, pressure, time, etc.) can be optimized to improve the recovery rate and purity of Zr and Hf.

[0062] In a preferred embodiment of the present invention, the ion exchange using the macroporous cationic adsorption resin in step S30 specifically includes the following steps:

[0063] b1. Resin pretreatment: Clean the macroporous cationic adsorption resin to remove impurities and unfixed ions, and regenerate the resin with dilute hydrochloric acid to restore its ion exchange capacity;

[0064] b2. Column loading: Load the pretreated resin into the ion exchange column to ensure that the resin layer is uniform and tight;

[0065] b3. Loading: passing the extractant phase containing Zr and Hf obtained after countercurrent extraction through the ion exchange column at a certain flow rate;

[0066] b4. Ion exchange: During the ion exchange process, Zr and Hf will be separated according to their different adsorption capacities on the resin. The ion Hf with stronger adsorption capacity will be preferentially adsorbed by the resin, while the ion Zr with weaker adsorption capacity will remain more in the solution.

[0067] b5. Elution and collection: Use the eluent to pass through the ion exchange column at a certain flow rate to elute the ions adsorbed on the resin, and collect Zr and Hf in the eluate separately for further purification and recovery;

[0068] b6. Resin regeneration and reuse: After completing an ion exchange, the resin is regenerated for reuse. Through the specific properties of the macroporous cationic adsorption resin and its different adsorption capacities for Zr and Hf ions, the effective separation of the two in the ion exchange process is achieved. This method not only improves the separation efficiency, but also significantly improves the purity of the product and reduces the production cost. The resin pretreatment step ensures the cleanliness and ion exchange capacity of the resin, providing a good foundation for the subsequent ion exchange process. The column loading step ensures the uniformity and tightness of the resin layer, which is conducive to the smooth progress of the ion exchange process. In the loading step, by controlling the flow rate of the extractant phase, the full contact and adsorption of Zr and Hf ions on the resin are achieved. In the ion exchange step, according to the difference in the adsorption capacity of Zr and Hf on the resin, the two are effectively separated. The elution and collection steps ensure the efficient recovery and purification of the separated Zr and Hf ions. Finally, the resin regeneration and reuse steps not only reduce the production cost, but also embody the concept of environmental protection and sustainability.

[0069] The ion exchange process can further optimize the separation effect by adjusting the parameters such as the type, particle size, loading amount of the resin, and the type, concentration and flow rate of the eluent. The selection of macroporous cationic adsorption resins with high selectivity and high adsorption capacity can significantly improve the separation efficiency and purity of Zr and Hf. By adjusting the particle size and loading amount of the resin, the bed height and porosity of the ion exchange column can be controlled, thereby affecting the diffusion rate and adsorption efficiency of the ions. The type and concentration of the eluent have an important influence on the elution effect and the purity of the product. The appropriate eluent can be selected according to the actual situation, and its concentration and flow rate can be adjusted to achieve the best elution effect. In addition, other separation techniques, such as solvent extraction and electrochemical separation, can be combined to further improve the separation efficiency and purity of Zr and Hf. Before ion exchange, the impurity ions in the extractant phase can be removed by solvent extraction technology to reduce interference with the ion exchange process. After ion exchange, electrochemical separation technology can be used to further purify the collected Zr and Hf ions to obtain higher purity products.

[0070] The present invention can be further configured as follows in a preferred embodiment: in step S30, the model of the macroporous cationic adsorption resin is D001, the resin bed height is 50cm, the ion exchange flow rate is controlled at 1BV / h, and the resin regeneration cycle and the regeneration agent concentration are adjusted to maintain the high adsorption capacity of the resin, ensuring that the separation efficiency of Zr and Hf is not less than 99%. The macroporous cationic adsorption resin of model D001 can efficiently adsorb and separate Zr and Hf ions due to its excellent ion exchange performance and selectivity. The resin bed height is set to 50cm, which ensures that the resin and the extractant phase are fully contacted during the ion exchange process, thereby improving the separation efficiency. The ion exchange flow rate is controlled at 1BV / h, which not only ensures the smooth progress of the ion exchange process, but also avoids the problems of resin bed disturbance and incomplete ion exchange caused by too fast flow rate. By adjusting the resin regeneration cycle and the regeneration agent concentration, the service life of the resin is effectively extended, its high adsorption capacity is maintained, and the separation efficiency of Zr and Hf is ensured to be not less than 99%, which significantly improves the purity and separation efficiency of the product and reduces the production cost.

[0071] The macroporous cationic adsorption resin of model D001 has stable chemical properties and good mechanical strength, and can maintain stable ion exchange performance in a wide range of pH and temperature. The resin bed height and ion exchange flow rate can be flexibly adjusted according to factors such as the concentration of Zr and Hf ions in the extractant phase, the adsorption capacity of the resin, and production requirements to achieve the best separation effect. At the same time, the regulation of the resin regeneration cycle and the concentration of the regenerant is also crucial. When the adsorption capacity of the resin is close to saturation, regeneration should be carried out in time to avoid permanent failure of the resin. The selection of the regenerant concentration should be weighed according to the adsorption characteristics and regeneration efficiency of the resin, ensuring both the full regeneration of the resin and avoiding waste and environmental pollution caused by excessive regenerant concentration. In addition, the use and maintenance strategy of the resin can be optimized by regularly testing the adsorption performance and separation efficiency of the resin, and statistical analysis based on production data, so as to further improve the efficiency and quality of zirconium and hafnium separation.

[0072] In a preferred embodiment, the present invention can be further configured as follows: in step S30, hydrochloric acid with a concentration of 3 mol / L is used as the eluent, the elution temperature is 40° C., and the elution time is 2 hours. By precisely controlling the elution conditions, ZrCl4 and HfCl4 adsorbed by the resin are effectively recovered, and the formula used is:

[0073]

[0074] Wherein R represents the recovery rate of ZrCl4, R′ represents the recovery rate of HfCl4, [ZrCl4] recovery liquid and [HfCl4] recovery liquid represent the concentrations of ZrCl4 and HfCl4 in the recovery liquid, respectively, [total ZrCl4] resin adsorption and [total HfCl4] resin adsorption represent the total amount of ZrCl4 and HfCl4 adsorbed by the resin, respectively. The higher the recovery rate, the better the elution effect. The ZrCl4 and HfCl4 adsorbed by the resin are effectively recovered. Hydrochloric acid with a concentration of 3 mol / L is used as the eluent, which not only ensures the elution effect, but also avoids the damage to the resin structure caused by excessively high hydrochloric acid concentration and the complexity of subsequent treatment of the eluent. The elution temperature is set at 40°C, which is conducive to accelerating the elution process and improving the elution efficiency. At the same time, it avoids the problems of resin thermal decomposition and eluent volatilization caused by excessive temperature. The elution time is controlled at 2 hours to ensure the full progress of the elution process and improve the recovery rate of ZrCl4 and HfCl4. These elution conditions are precisely controlled.

[0075] Precise control of elution conditions is crucial to improving the recovery rate. Slight changes in the concentration, temperature and time of the eluent may have a significant impact on the recovery rate. Therefore, these parameters need to be strictly controlled during operation to ensure the stability and repeatability of the elution process. In addition, the recovered liquid after elution can be further purified by treatments such as solvent extraction, evaporation and crystallization to obtain higher purity ZrCl4 and HfCl4 products. At the same time, for the regeneration and reuse of the resin, it is also necessary to conduct regular testing and evaluation based on the adsorption performance and elution effect of the resin to ensure the long-term stability and high efficiency of the resin. When the adsorption capacity of the resin drops to a certain extent, its adsorption performance can be restored by appropriate regeneration treatment, thereby extending the service life of the resin and reducing production costs.

[0076] In a preferred embodiment, the present invention can be further configured as follows: in step S40, the distillation and purification adopts a multi-stage distillation tower, in step S40, the vacuum distillation equipment adopts a condensing vacuum pump, the vacuum distillation conditions are a vacuum degree of 10^-4Pa, a temperature of 1200°C, a hammer crusher is used for crushing, and the particle size is controlled between 0.5mm and 2mm. The use of a multi-stage distillation tower for distillation and purification can significantly improve the purification efficiency, reduce the impurity content, and obtain higher purity zirconium and hafnium products. The design of the multi-stage distillation tower enables each stage to further purify the material, thereby gradually removing impurities therein and improving the purity of the product. At the same time, using a condensing vacuum pump as a vacuum distillation equipment and distilling under the conditions of a vacuum degree of 10^-4Pa and a temperature of 1200°C can significantly reduce the energy consumption in the distillation process, improve the distillation efficiency, and avoid the oxidation problem caused by the contact of the material with air at high temperature. In addition, a hammer crusher is used in the crushing stage, and the particle size is controlled between 0.5mm and 2mm, which can ensure the uniformity and stability of the material in the subsequent processing process, which is conducive to improving the purification effect and product quality.

[0077] The design of the multi-stage distillation tower can be flexibly adjusted according to actual needs, such as increasing the number of distillation stages, adjusting the pressure and temperature between each stage, etc., to further optimize the purification effect. In actual operation, the appropriate number of distillation stages and operating conditions can be selected according to the type and content of impurities in the material and the purity requirements of the target product. At the same time, the use of the condensing vacuum pump also needs to pay attention to its maintenance and maintenance to ensure its long-term stable operation. In addition, the selection and particle size control of the hammer crusher also need to be comprehensively considered according to the properties of the material and the requirements of the subsequent processing flow. For materials with higher hardness, a more powerful hammer crusher can be selected; for products that require finer particle size, this can be achieved by adjusting the size of the crusher's discharge port or adding screening equipment. In practical applications, the implementation of these measures can significantly improve the efficiency and quality of zirconium and hafnium separation and purification, and provide strong technical support for the development of related industries.

[0078] In a preferred embodiment, the present invention can be further configured as follows: the method also includes a pretreatment step of raw material chemical composition analysis, using an X-ray fluorescence spectrometer to analyze the content of zirconium, hafnium and major impurities in zircon, and dynamically adjusting the parameters of subsequent processing steps according to the analysis results, such as chlorination temperature, extractant ratio, and ion exchange conditions, to achieve customized production and improve separation efficiency and product quality. Through the pretreatment step of raw material chemical composition analysis, the content of zirconium, hafnium and impurities in zircon can be accurately understood, providing accurate data support for subsequent processing steps. Based on these accurate data, key parameters such as chlorination temperature, extractant ratio, ion exchange conditions, etc. can be dynamically adjusted to achieve customized production. This customized production strategy can be flexibly adjusted according to the characteristics of different raw materials to maximize separation efficiency and product quality.

[0079] The pretreatment step of raw material chemical composition analysis is not limited to the use of X-ray fluorescence spectrometer, but can also be combined with other analytical techniques, such as inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectroscopy (AAS), etc., to obtain more comprehensive raw material information. At the same time, when dynamically adjusting the parameters of the subsequent processing steps, it is necessary to comprehensively consider multiple factors such as raw material characteristics, target product quality requirements, and production costs. For example, in the chlorination step, if the content of zirconium and hafnium in the raw material is high, the chlorination temperature can be appropriately increased to promote the chlorination reaction; in the extraction step, according to the type and content of impurities in the raw material, the ratio of the extractant can be adjusted to improve the extraction efficiency and selectivity; in the ion exchange step, according to the ratio of zirconium and hafnium in the raw material and the purity requirements of the target product, the selection of ion exchange resin, bed height, flow rate and other conditions can be optimized. Through these refined adjustments, the efficiency and product quality of zirconium and hafnium separation can be further improved to meet the needs of different customers.

[0080] As shown in the following table, the recovery rates of the separation method of the present invention and the separation methods of the prior art (solvent extraction, fractional crystallization and ion exchange) are compared.

[0081]

[0082]

[0083] In summary, the method for separating zirconium and hafnium from zircon of the present invention has significant advantages over the prior art. By precisely controlling the conditions and parameters of each step, efficient and continuous separation of zirconium and hafnium is achieved, while improving the purity of the product and reducing the production cost. In addition, the entire process is more environmentally friendly, reducing the use of chemical reagents and the generation of waste. Therefore, the separation method of the present invention will provide strong support for the effective utilization of zirconium and hafnium resources and promote scientific and technological progress and development in related fields.

[0084] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0085] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for separating zirconium and hafnium from zircon, characterized in that: The following steps are involved: S10, raw material pretreatment, the zircon raw material is crushed into a particle size of 0.5mm to 5mm by a jaw crusher, and the particles with uniform particle size are obtained by a vibration screening device, and then the ore dressing and purification technology combining gravity separation, magnetic separation and electric separation is used to remove gangue and iron-titanium impurities according to the differences in density, magnetism and electrical properties; S20, chlorination reaction, mixing the pretreated zircon with carbon in a mass ratio of 1:0.8, placing in a high-temperature chlorination furnace, chlorinating at a temperature of 850° C. to 1100° C. for 4 hours to generate a (Zr, Hf)Cl4 mixed gas, and collecting and purifying the gas through a condensation and washing device to ensure the purity of zirconium and hafnium chloride in the gas; S30, solvent extraction and ion exchange combined separation, using the improved MIBK-SCN system as the extractant, through the countercurrent extraction process, according to the difference in the distribution coefficient of Zr and Hf in the extractant, to achieve preliminary separation, then use macroporous cationic adsorption resin for ion exchange, further according to the different adsorption capacity of Zr and Hf on the resin, to achieve the purpose of efficient separation; S40, product preparation, the separated ZrCl4 and HfCl4 are subjected to multi-stage distillation purification to remove trace impurities; then, under the protection of inert gas, a magnesium thermal reduction method is used to carry out a reduction reaction at 700°C to obtain sponge zirconium and sponge hafnium; finally, residual chloride and metallic magnesium are removed by vacuum distillation, and after crushing, a zirconium and hafnium product with uniform particle size is obtained.

2. The method for separating zirconium and hafnium from zircon according to claim 1, characterized in that: In the raw material pretreatment step of step S10, the operating speed of the jaw crusher is set to 300 revolutions per minute, and the vibrating screening equipment adopts a 20-mesh to 100-mesh screen to ensure that the obtained particle size is uniform. In the process of gravity separation, the density difference between mineral particles in the ore is utilized to separate the mineral particles through the action of the gravity field, wherein the gravity separation adopts one of jigging, shaking table, and chute for separation, and in the magnetic separation, the magnetic minerals are separated from the non-magnetic minerals under the action of the magnetic field, wherein the magnetic separation equipment adopted is one of a drum magnetic separator and a disc magnetic separator, and in the process of electric separation, the mineral particles are separated under the action of the electric field, and the separation efficiency can be precisely controlled by adjusting the parameters of the magnetic field strength and the electric field voltage, and the electric separation equipment adopts an electrostatic separator.

3. The method for separating zirconium and hafnium from zircon according to claim 1, characterized in that: In step S20, an inert gas protection can be introduced into the chlorination furnace, and the reaction formula is 2(Zr,Hf)O2+C+4Cl2→2(Zr,Hf)Cl4+CO2, wherein the inert gas used is nitrogen. When nitrogen is introduced into the chlorination furnace, it should be continuously introduced into the chlorination furnace at a certain flow rate to maintain the stability of the atmosphere in the furnace. At the same time, during the chlorination process, it is necessary to regularly sample and analyze the gas composition, and adjust the chlorination temperature and time according to the analysis results to ensure the generation rate and purity of the (Zr,Hf)Cl4 mixed gas.

4. The method for separating zirconium and hafnium from zircon according to claim 1, characterized in that: The volume ratio of the improved MIBK-SCN system extractant in step S30 is MIBK:SCN=3:1, and the countercurrent extraction stage is set to 5. By precisely controlling the flow rate, temperature and pH value of the extractant, efficient separation of Zr and Hf is achieved. The formula used is: KD is the separation coefficient, which is used to quantify the distribution difference between Zr and Hf between the extractant and the aqueous phase, where [Zr] and [Hf] represent the concentrations of zirconium and hafnium in the extractant and the aqueous phase, respectively. The larger the KD value, the greater the distribution difference between Zr and Hf in the extractant, the better the separation effect, and the separation coefficient is greater than 1.5; In step S30, the countercurrent extraction process comprises the following steps: a1. Preparation stage: ensure that the extraction tower is clean and dry, check and adjust the flow rate control system of the extraction tower to ensure stable and controllable liquid flow, prepare the modified MIBK-SCN system extractant and aqueous solution, wherein the aqueous solution is a solution containing Zr and Hf; a2. Loading stage: The extractant is loaded into the upper part of the extraction tower, while the aqueous solution enters from the lower part, ensuring that the extractant and the aqueous solution form a clear interface in the tower to avoid mixing; a3. Extraction stage: Turn on the flow rate control system to make the aqueous solution flow upward from the bottom of the extraction tower at a certain flow rate, while the extractant flows downward from the top. During the extraction process, Zr and Hf will gradually transfer from the aqueous phase to the extractant phase according to their distribution coefficient differences in the extractant. The design of the extraction tower should allow the two phases to fully contact to ensure efficient solute transfer; a4. Collection stage: collecting the extractant phase rich in Zr and Hf at the top of the extraction tower, and collecting the aqueous phase solution from which most of the Zr and Hf have been removed at the bottom of the extraction tower; a5. Post-treatment stage: The collected extractant phase is further treated, washed and stripped to recover Zr and Hf, and the raffinate is properly treated.

5. The method for separating zirconium and hafnium from zircon according to claim 4, characterized in that: The ion exchange with the macroporous cationic adsorption resin in step S30 specifically includes the following steps: b1. Resin pretreatment: Clean the macroporous cationic adsorption resin to remove impurities and unfixed ions, and regenerate the resin with dilute hydrochloric acid to restore its ion exchange capacity; b2. Column loading: Load the pretreated resin into the ion exchange column to ensure that the resin layer is uniform and tight; b3. Loading: passing the extractant phase containing Zr and Hf obtained after countercurrent extraction through the ion exchange column at a certain flow rate; b4. Ion exchange: During the ion exchange process, Zr and Hf will be separated according to their different adsorption capacities on the resin. The ion Hf with stronger adsorption capacity will be preferentially adsorbed by the resin, while the ion Zr with weaker adsorption capacity will remain more in the solution. b5. Elution and collection: Use the eluent to pass through the ion exchange column at a certain flow rate to elute the ions adsorbed on the resin, and collect Zr and Hf in the eluate separately for further purification and recovery; b6. Resin regeneration and reuse: After completing an ion exchange, the resin is regenerated for reuse.

6. The method for separating zirconium and hafnium from zircon according to claim 5, characterized in that: In step S30, the model of the macroporous cationic adsorption resin is D001, the resin bed height is 50 cm, the ion exchange flow rate is controlled at 1 BV / h, and the high adsorption capacity of the resin is maintained by adjusting the resin regeneration cycle and the regeneration agent concentration to ensure that the separation efficiency of Zr and Hf is not less than 99%.

7. The method for separating zirconium and hafnium from zircon according to claim 5, characterized in that: In step S30, hydrochloric acid with a concentration of 3 mol / L is used as the eluent, the elution temperature is 40° C., and the elution time is 2 hours. By precisely controlling the elution conditions, the ZrCl4 and HfCl4 adsorbed on the resin are effectively recovered. The formula used is: Among them, R represents the recovery rate of ZrCl4, R′ represents the recovery rate of HfCl4, [ZrCl4] recovery liquid and [HfCl4] recovery liquid represent the concentrations of ZrCl4 and HfCl4 in the recovery liquid, respectively, [total ZrCl4] resin adsorption and [total HfCl4] resin adsorption represent the total amount of ZrCl4 and HfCl4 adsorbed by the resin, respectively. The higher the recovery rate, the better the elution effect, and the ZrCl4 and HfCl4 adsorbed by the resin are effectively recovered.

8. The method for separating zirconium and hafnium from zircon according to claim 1, characterized in that: In step S40, the distillation and purification adopts a multi-stage distillation tower. In step S40, the vacuum distillation equipment adopts a condensing vacuum pump. The conditions of vacuum distillation are vacuum degree 10^-4Pa and temperature 1200°C. The crushing treatment adopts a hammer crusher and the particle size is controlled between 0.5mm and 2mm.

9. A method for separating zirconium and hafnium from zircon according to any one of claims 1 to 8, characterized in that: The method also includes a pretreatment step of analyzing the chemical composition of the raw materials, using an X-ray fluorescence spectrometer to analyze the content of zirconium, hafnium and major impurities in zircon, and dynamically adjusting the parameters of subsequent treatment steps according to the analysis results, such as chlorination temperature, extractant ratio, and ion exchange conditions, to achieve customized production and improve separation efficiency and product quality.

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