Nano yttrium carbonate as well as shape-controllable preparation method and application thereof

Abstract

The invention belongs to the technical field of rare earth hydrometallurgy, and discloses nanometer yttrium carbonate, the particle size of the nanometer yttrium carbonate is 40-120nm, the nanometer yttrium carbonate can be in a sphere-like shape, a sheet shape or a rod shape, so that the nanometer yttrium carbonate can be applied to different fields and scenes, the particle size distribution is uniform, and the catalytic efficiency can be improved. The invention further discloses a preparation method of the shape-controllable nano yttrium carbonate, and the shape of the product nano yttrium carbonate is controlled by regulating and controlling the preparation process of the nano yttrium carbonate. The method for preparing the nanometer yttrium carbonate with different morphologies by adopting one process route has the multiple advantages of high efficiency, low cost, flexibility, environmental protection and the like, can quickly respond to market requirements, improves the product quality consistency, and reduces the production cost and the environmental influence at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of rare earth hydrometallurgy, and particularly relates to a nano yttrium carbonate and a preparation method and application thereof with controllable morphology. Background Art

[0002] Due to its remarkable "small size" effect and unique physical and chemical properties, nano yttrium carbonate can effectively prevent catalyst poisoning and deactivation, thus greatly prolonging the service life of the catalyst. It has now become one of the key materials indispensable for optimizing catalyst performance.

[0003] The preparation method plays a crucial role in the performance of nano yttrium carbonate and further affects its use effect. At present, the preparation methods mainly rely on traditional chemical synthesis routes, including sol-gel method, hydrothermal method, emulsion method, chemical co-precipitation method, solid-phase reaction method, and combustion method, etc. Among them, the sol-gel method forms a sol and then transforms it into a gel. Although it can obtain a catalyst with a high specific surface area, the process involves multiple washing and drying steps, which are cumbersome. The hydrothermal method promotes the reaction of raw materials under high temperature and high pressure. Although it is beneficial to the formation of a specific crystal phase, it has high requirements for equipment and harsh operating conditions. The emulsion method reacts by forming tiny droplets. Although it can achieve uniform dispersion of the product, the subsequent separation and purification steps are complex. The chemical co-precipitation method has a relatively low cost, but the control of precipitation conditions has a significant impact on the morphology and particle size of the final product. The solid-phase reaction method directly mixes and reacts solid raw materials. Although the operation is simple, the reaction efficiency is low and the energy consumption is large. The combustion method prepares products through a rapid combustion reaction. Although the reaction is rapid, the cost is high and the combustion process is not easy to control. In addition, there are some emerging green chemical synthesis methods that are gradually developing. They aim to reduce the generation of harmful substances and improve the synthesis efficiency. However, these new technologies are still in the laboratory stage and large-scale application still takes time.

[0004] Currently, commercially available yttrium carbonate is mostly micron-sized, and there is little nano-sized yttrium carbonate. For some products labeled as nano yttrium carbonate, it is found in actual use that they cannot reach the nano level.

[0005] Our company found in the research and development of nano-level yttrium carbonate products that due to its "small size" effect, nano-sized yttrium carbonate has a higher specific surface area, and has a significant effect on improving the utilization rate and catalytic efficiency of the catalyst. In addition, the R & D personnel also found that different microscopic morphologies of yttrium carbonate also have the following unique performance characteristics:

[0006] For example: spherical-like yttrium carbonate has good dispersibility and fluidity, and exhibits excellent mass transfer performance. The spherical-like structure helps to reduce the aggregation between particles and improve the utilization rate of the catalyst. At the same time, the curvature of the spherical-like surface enables reactant molecules to be more easily adsorbed and desorbed, thus accelerating the catalytic reaction rate.

[0007] Due to its unique one-dimensional structure, rod-shaped yttrium carbonate can provide more active sites and promote the catalytic reaction.

[0008] Sheet-like yttrium carbonate, with its ultrathin two-dimensional structure and large specific surface area, not only increases the number of catalytic active sites but also facilitates the diffusion and adsorption of reactant molecules.

[0009] Therefore, on the basis of product development, seeking a preparation method that can regulate different morphologies to enable the product to freely switch between different morphologies is a path more conducive to industrial development.

[0010] Based on the requirements of the above-mentioned background technology, developing nano-level yttrium carbonate products and a preparation method that can flexibly regulate their morphologies have become urgent problems for those skilled in the art to solve. Summary of the Invention

[0011] The first object of the present invention is to provide a nano yttrium carbonate.

[0012] The second object of the present invention is to provide a preparation method for controllable morphology of nano yttrium carbonate.

[0013] The third object of the present invention is to provide an application of nano yttrium carbonate.

[0014] I. Nano yttrium carbonate

[0015] The particle size of the nano yttrium carbonate of the present invention is 40 - 120 nm, and the particle size distribution is uniform, ensuring the uniform distribution of catalytic active sites and helping to improve the catalytic efficiency.

[0016] Preferably, the microscopic morphology of the nano yttrium carbonate is spherical-like, with a particle size of 40 - 60 nm. The spherical-like structure helps to reduce the aggregation between particles, improves the utilization rate of the catalyst, and the curvature of the spherical-like surface enables reactant molecules to be more easily adsorbed and desorbed, thus accelerating the catalytic reaction rate.

[0017] Preferably, the microscopic morphology of the nano yttrium carbonate is sheet-like, with a particle size of 40 - 70 nm. Sheet-like yttrium carbonate, with its ultrathin two-dimensional structure and large specific surface area, not only increases the number of catalytic active sites but also facilitates the diffusion and adsorption of reactant molecules.

[0018] Preferably, the microscopic morphology of the nano yttrium carbonate is rod-shaped, with a particle size of 90 - 120 nm. Due to its unique one-dimensional structure, rod-shaped yttrium carbonate can provide more active sites and promote the catalytic reaction.

[0019] II. Preparation method for controllable morphology of nano yttrium carbonate

[0020] A preparation method for controllable morphology of nano yttrium carbonate, which is used to prepare the above-mentioned nano yttrium carbonate. By regulating the preparation process of nano yttrium carbonate, the morphology of nano yttrium carbonate can be controlled. Nano yttrium carbonate with different morphologies is suitable for different application fields and scenarios. The specific steps are as follows:

[0021] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 100-250 g / L. Mix the yttrium chloride solution and a (NH4)2S solution (with a concentration of 15-50 g / L), and then heat and stir to obtain a high-purity yttrium chloride solution with a mass fraction of 90-98%;

[0022] (2) Dissolve the precipitant in water and heat it to obtain a precipitant solution at a certain temperature. The temperature of the precipitant solution is 40-80 °C; the precipitant is at least one of sodium carbonate, ammonium carbonate, and ammonium bicarbonate; the mass concentration of the precipitant is 150-500%;

[0023] (3) Dissolve the surfactant in water and heat it to obtain a surfactant solution at a certain temperature. The temperature of the surfactant is 40-60 °C; the surfactant is at least one of sodium dodecyl sulfate (SDS for short), sodium dodecyl benzene sulfonate (SDBS for short), polyvinylpyrrolidone (PVP for short), and polyethylene glycol (PEG for short); the dosage of the surfactant is 0.01%-0.5% of the dosage of yttrium chloride;

[0024] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain a nano yttrium carbonate slurry. The flow rates of both the yttrium chloride solution and the precipitant solution are 200-500 mL / min, and the rotation speed of the multiphase interface reactor is 3000-4500 rpm. Use the multiphase interface reactor for rapid synthesis reaction to form nano yttrium carbonate crystals;

[0025] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a nano yttrium carbonate precursor suspension. The flow rates of both the surfactant solution and the nano yttrium carbonate slurry are 250-450 mL / min, and the rotation speed of the multiphase interface reactor is 2000-4500 rpm. Adjust the thickness and size of the bubbles in the reaction microzone by regulating the material flow rate and rotation speed, thereby restricting the growth environment of the crystals, and further controlling the particle size and morphology of the target particles;

[0026] (6) Age, filter, wash, dry, and pulverize the nano yttrium carbonate suspension obtained in step (5) to obtain nano yttrium carbonate powder. At this stage, the nano yttrium carbonate crystals have matured and their morphology has been fixed. The post-treatment is mainly to control the impurity Na + , and eliminate the impurity Na + by repeated washing to improve the product purity.

[0027] Preferably, the molar ratio of yttrium chloride to the precipitating agent is 1:1.6 - 1:3.0.

[0028] Preferably, to prepare nano yttrium carbonate with a spherical-like morphology:

[0029] In step (3), the surfactants selected are SDS and PEG4000, and the dosages of SDS and PEG4000 are 0.5% and 0.05% of the dosage of yttrium chloride, respectively;

[0030] In step (4), the flow rates of the yttrium chloride solution and the precipitating agent solution pumped into the multiphase interface reactor are 300 mL / min and 450 mL / min, respectively; the rotation speed of the multiphase interface reactor is 3500 rpm; use the multiphase interface reactor for rapid synthesis reaction to form nano yttrium carbonate crystals. Heating the raw materials is to further control the maturity of the crystals. To control the spherical-like morphology and prevent the collapse and deformation of the initial crystals;

[0031] In step (5), the flow rates of the surfactant solution and the nano yttrium carbonate slurry pumped into the multiphase interface reactor are 400 mL / min and 450 mL / min, respectively; the rotation speed of the multiphase interface reactor is 3500 rpm.

[0032] Preferably, to prepare nano yttrium carbonate with a flaky morphology:

[0033] In step (3), the surfactant selected is SDS, and the dosage of SDS is 0.5% of the dosage of yttrium chloride;

[0034] In step (4), the flow rates of the yttrium chloride solution and the precipitating agent solution pumped into the multiphase interface reactor are 300 mL / min and 400 mL / min, respectively; the rotation speed of the multiphase interface reactor is 3500 rpm;

[0035] In step (5), the flow rates of the surfactant solution and the nano yttrium carbonate slurry pumped into the multiphase interface reactor are 250 mL / min and 300 mL / min, respectively; the rotation speed of the multiphase interface reactor is 3000 rpm.

[0036] Preferably, to prepare nano yttrium carbonate with a rod-like morphology:

[0037] In step (3), the surfactants used are PVP and PEG4000, and the dosages of PVP and PEG4000 are 0.5% and 0.05% of the dosage of yttrium chloride, respectively.

[0038] In step (4), the flow rates of the yttrium chloride solution and the precipitant solution pumped into the multiphase interface reactor are 450 mL / min and 300 mL / min, respectively; the rotation speed of the multiphase interface reactor is 4000 rpm.

[0039] In step (5), the flow rates of the surfactant solution and the nano yttrium carbonate slurry pumped into the multiphase interface reactor are 300 mL / min and 300 mL / min, respectively; the rotation speed of the multiphase interface reactor is 2500 rpm.

[0040] III. Application of Nano Yttrium Carbonate

[0041] The above-mentioned nano yttrium carbonate is applied to the field of heavy oil cracking catalysis.

[0042] The present invention has the following beneficial effects:

[0043] 1. A nano yttrium carbonate disclosed by the present invention has a particle size of 40 - 120 nm, and the particle size distribution is uniform, ensuring the uniform dispersion of the active sites of the catalyst, thus significantly improving the catalytic efficiency and making the reaction faster and more efficient.

[0044] 2. The present invention can prepare nano yttrium carbonate with different micro - morphologies such as spherical, rod - shaped, and sheet - shaped. Preparing nano yttrium carbonate with different morphologies is to meet its diverse application requirements in the fields of materials science, catalysis, optics, electronics, etc., to meet the different needs of customers in multiple fields, further refine and classify the yttrium carbonate catalyst, and provide more matching products for the needs of customers in multiple fields.

[0045] Nano - materials with different morphologies have unique physical and chemical properties, and these properties are closely related to their morphologies. At the same time, preparing nano yttrium carbonate with different morphologies by one process route has multiple advantages such as high efficiency, low cost, flexibility, and environmental protection, can quickly respond to market demands, improve the consistency of product quality, and at the same time reduce production costs and environmental impacts.

[0046] 3. A preparation method for controllable morphology of nano yttrium carbonate disclosed by the present invention can effectively remove impurity ions such as iron, lead, zinc, and copper in yttrium chloride hexahydrate by using ammonium sulfide solution to obtain a high-purity yttrium chloride hexahydrate solution. Subsequently, through precipitation reaction with a precipitant and post-treatment procedures, high-purity yttrium carbonate with a purity of 99.1%-99.5% can be obtained; the use of a multiphase interface reactor improves the reaction efficiency and enables continuous production, and the product yield is increased to 98%; by selecting different surfactants and adjusting the material flow rate and rotation speed to adjust the thickness and size of bubbles in the reaction microzone, the growth environment of grains can be restricted, and thus the particle size and morphology of the target nano yttrium carbonate particles can be controlled.

[0047] Surfactant molecules have hydrophilic heads and hydrophobic tails, can adsorb at the interface, reduce the surface energy and interfacial tension, and thus affect the nucleation, growth, and assembly processes of materials; (1) Surfactants affect the nucleation rate and growth direction by changing the chemical environment in the solution. For example, certain surfactants will preferentially adsorb on specific crystal planes, inhibit the growth in this direction, resulting in anisotropic growth and forming structures such as nanowires or nanoplates. (2) Surfactant molecules can form stable micelles in the solution, guide the growth of materials on or inside their surfaces, and form specific morphologies. (3) Surfactants affect the stability of droplets or bubbles by reducing the interfacial tension, thereby regulating the morphology of materials. For example, in the microemulsion method, surfactants can stabilize the gas-liquid phase interface and form a uniform growth space for nanoparticles. Description of the Drawings

[0048] Figure 1 It is a scanning electron microscope image of spherical nano yttrium carbonate prepared in Example 1.

[0049] Figure 2 It is a scanning electron microscope image of flaky nano yttrium carbonate prepared in Example 2.

[0050] Figure 3 It is a scanning electron microscope image of rod-shaped nano yttrium carbonate prepared in Example 3.

[0051] Figure 4 It is a scanning electron microscope image of nano yttrium carbonate prepared in Comparative Example 1.

[0052] Figure 5 It is an XRD pattern of nano yttrium carbonate. Detailed Embodiments

[0053] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] Refer to Figures 1 - 3, the spherical-like, flake-like, and rod-like morphologies of nano yttrium carbonate were respectively prepared.

[0055] Example 1: Preparation of nano yttrium carbonate with spherical-like morphology

[0056] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 100 g / L; then mix the yttrium chloride solution and (NH4)2S solution (with a concentration of 15 g / L), and heat and stir at 60 °C for 30 min with a stirring speed of 300 rap / min to obtain a high-purity yttrium chloride solution with a mass fraction of 90%.

[0057] (2) Dissolve a certain mass of sodium carbonate in water and heat to obtain a precipitant solution at 60 °C with a mass concentration of 300 g / L.

[0058] (3) Dissolve surfactant SDS and PEG4000 in water and heat to obtain a surfactant solution at 60 °C; among them, the dosages of SDS and PEG4000 are 0.5% and 0.05% of the yttrium chloride dosage respectively.

[0059] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain nano yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 200 mL / min and 500 mL / min respectively, and the rotation speed of the multiphase interface reactor is 3000 rpm.

[0060] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a nano yttrium carbonate precursor suspension; the flow rates of the surfactant solution and the nano yttrium carbonate slurry are 400 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 3500 rpm.

[0061] (6) Age the nano yttrium carbonate suspension prepared in step (5) (at 80 °C for 2 h), filter (using a Buchner funnel with pressure filtration, pressure 0.08 Mpa), wash (by suction filtration, solid-liquid ratio 6:1), dry (at 80 °C for 12 h), and pulverize (using a multi-functional pulverizer for 3 min) to obtain nano yttrium carbonate powder with spherical-like morphology, and its particle size distribution is 40 - 60 nm.

[0062] The washing condition is that the conductivity of the filtrate is less than 100 μs / cm.

[0063] Example 2: Preparation of nano yttrium carbonate with spherical-like morphology

[0064] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 150 g / L; then mix the yttrium chloride solution and (NH4)2S solution (with a concentration of 30 g / L), and heat and stir at 60 °C for 30 min with a stirring speed of 300 rap / min to obtain a high-purity yttrium chloride solution with a mass fraction of 96%.

[0065] (2) Dissolve a certain mass of sodium carbonate in water and heat to obtain a precipitant solution at 60 °C with a mass concentration of 450 g / L.

[0066] (3) Dissolve surfactant SDS and PEG4000 in water and heat to obtain a surfactant solution at 60 °C; among them, the dosages of SDS and PEG4000 are 0.5% and 0.05% of the dosage of yttrium chloride respectively.

[0067] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain nano-sized yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 300 mL / min and 450 mL / min respectively, and the rotation speed of the multiphase interface reactor is 3500 rpm.

[0068] (5) Pump the surfactant solution prepared in step (3) and the nano-sized yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a suspension of nano-sized yttrium carbonate precursor; the flow rates of the surfactant solution and the nano-sized yttrium carbonate slurry are 450 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 4500 rpm.

[0069] (6) Age the nano-sized yttrium carbonate suspension prepared in step (5) (at 80 °C for 2 h), filter (using a Buchner funnel with pressure filtration, pressure 0.08 Mpa), wash (by suction filtration washing, solid-liquid ratio 6:1), dry (at 80 °C for 12 h), and pulverize (using a multi-functional pulverizer, for 3 min) to obtain nano-sized yttrium carbonate powder with a spherical-like morphology, and its particle size distribution is 40 - 50 nm.

[0070] The washing condition is that the conductivity of the filtrate is less than 100 μs / cm.

[0071] Example 3 Preparation of nano-sized yttrium carbonate with a flaky morphology

[0072] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 150 g / L; then mix the yttrium chloride solution and (NH4)2S solution (with a concentration of 30 g / L), and heat and stir at 60 °C for 30 min with a stirring speed of 300 rap / min to obtain a high-purity yttrium chloride solution with a mass fraction of 96%.

[0073] (2) Dissolve a certain mass of sodium carbonate in water and heat it to obtain a precipitant solution at 60°C with a mass concentration of 200 g / L.

[0074] (3) Dissolve the surfactant SDS in water to obtain a surfactant solution; among them, the dosage of SDS is 0.5% of the dosage of yttrium chloride.

[0075] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain nano yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 300 mL / min and 400 mL / min respectively, and the rotation speed of the multiphase interface reactor is 3500 rpm.

[0076] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a suspension of nano yttrium carbonate precursor; the flow rates of the surfactant solution and the nano yttrium carbonate slurry are 250 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 3000 rpm;

[0077] (6) Age the nano yttrium carbonate suspension prepared in step (5) (at 25°C for 2 h), filter it (using a Buchner funnel for pressure filtration, with a pressure of 0.08 Mpa), wash it (by suction filtration washing, with a solid-liquid ratio of 6:1), dry it (at 80°C for 12 h), and pulverize it (using a multi-functional pulverizer for 3 min) to obtain nano yttrium carbonate powder with a flaky morphology, and its particle size distribution is 50 - 70 nm.

[0078] The washing condition is that the conductivity of the filtrate is less than 100 μs / cm.

[0079] Example 4 Preparation of Nano Yttrium Carbonate with Flaky Morphology

[0080] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 200 g / L; then mix the yttrium chloride solution and (NH4)2S solution (with a concentration of 50 g / L) and heat and stir at 60°C for 30 min, with a stirring speed of 300 rap / min, to obtain a high-purity yttrium chloride solution with a mass fraction of 98%.

[0081] (2) Dissolve a certain mass of ammonium bicarbonate in water and heat it to obtain a precipitant solution at 60°C with a mass concentration of 350 g / L.

[0082] (3) Dissolve the surfactant SDS in water to obtain a surfactant solution; among them, the dosage of SDS is 0.5% of the dosage of yttrium chloride.

[0083] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain a nano yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 400 mL / min and 500 mL / min respectively, and the rotation speed of the multiphase interface reactor is 4000 rpm.

[0084] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a suspension of nano yttrium carbonate precursor; the flow rates of the surfactant solution and the nano yttrium carbonate slurry are 300 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 3000 rpm;

[0085] (6) Age the nano yttrium carbonate suspension prepared in step (5) (at 25 °C for 2 h), filter it (using a Buchner funnel under pressure filtration, with a pressure of 0.08 Mpa), wash it (by suction filtration, with a solid-liquid ratio of 6:1), dry it (at 80 °C for 12 h), and pulverize it (using a multi-functional pulverizer for 3 min) to obtain nano yttrium carbonate powder with a flaky morphology, and its particle size distribution is 40 - 70 nm.

[0086] The washing condition is that the conductivity of the filtrate is less than 100 μs / cm.

[0087] Example 5 Preparation of nano yttrium carbonate with a rod-like morphology

[0088] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 200 g / L; then mix the yttrium chloride solution and (NH4)2S solution (with a concentration of 50 g / L) and heat and stir at 60 °C for 30 min, with a stirring speed of 300 rap / min, to obtain a high-purity yttrium chloride solution with a mass fraction of 98%.

[0089] (2) Dissolve a certain mass of sodium carbonate in water to obtain a precipitant solution at 60 °C with a mass concentration of 400 g / L.

[0090] (3) Dissolve the surfactant PVP and PEG4000 in water to obtain a surfactant solution; among them, the dosages of PVP and PEG4000 are 0.5% and 0.05% of the yttrium chloride dosage respectively.

[0091] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain a nano yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 400 mL / min and 300 mL / min respectively; the rotation speed of the multiphase interface reactor is 4000 rpm.

[0092] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a nano yttrium carbonate precursor suspension; the flow rates of the surfactant solution and the nano yttrium carbonate slurry are 300 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 2000 rpm;

[0093] (6) Age (at 80 °C for 5 h), filter (using a Buchner funnel with pressure filtration at a pressure of 0.08 Mpa), wash (by suction filtration with a solid-liquid ratio of 6:1), dry (at 80 °C for 12 h), and pulverize (using a multi-functional pulverizer for 3 min) the nano yttrium carbonate suspension prepared in step (5) to obtain nano yttrium carbonate powder with a rod-like morphology, and its particle size distribution is 100 - 120 nm.

[0094] Example 6 Preparation of nano yttrium carbonate with a rod-like morphology

[0095] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 250 g / L; then mix the yttrium chloride solution and (NH4)2S solution (with a concentration of 15 g / L) and heat and stir at 60 °C for 30 min with a stirring speed of 300 rap / min to obtain a high-purity yttrium chloride solution with a mass fraction of 90%.

[0096] (2) Dissolve a certain mass of sodium carbonate in water to obtain a precipitant solution at 60 °C with a mass concentration of 450 g / L.

[0097] (3) Dissolve the surfactant PVP and PEG4000 in water to obtain a surfactant solution; among them, the dosages of PVP and PEG4000 are 0.5% and 0.05% of the yttrium chloride dosage respectively.

[0098] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain a nano yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 500 mL / min and 500 mL / min respectively; the rotation speed of the multiphase interface reactor is 4500 rpm.

[0099] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a nano yttrium carbonate precursor suspension; the flow rates of the surfactant solution and the nano yttrium carbonate slurry are 350 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 2500 rpm;

[0100] (6) The nano yttrium carbonate suspension obtained in step (5) is aged (80 °C, 5 h), filtered (pressure filtration with a Buchner funnel, pressure 0.08 Mpa), washed (pressure filtration washing, solid-liquid ratio 6:1), dried (80 °C, 12 h), and pulverized (using a multi-functional pulverizer, 3 min) to obtain nano yttrium carbonate powder with a rod-like morphology, and its particle size distribution is 90 - 110 nm.

[0101] The washing condition is that the conductivity of the filtrate is less than 100 μs / cm.

[0102] Refer to Figure 5 , Figure 5 It shows that the characteristic peaks are in complete agreement with the hexagonal crystal system standard card (PDF 25 - 1010) of Y2(CO3)3·3H2O, and no other diffraction signals are detected. This result indicates that the prepared product is yttrium carbonate.

[0103] Comparative Example 1

[0104] Take the spherical nano yttrium carbonate product 1 prepared in Example 1, the flaky nano yttrium carbonate product 2 prepared in Example 3, the rod-like nano yttrium carbonate product 3 prepared in Example 5, as well as the commercially available micron-sized yttrium carbonate product 4 and the commercially available product 5 labeled as nano yttrium carbonate, and conduct heavy oil cracking catalytic experiments respectively. According to the total liquid yield and conversion rate, compare the catalytic effects of different products, and the results are shown in Table 1.

[0105] Table 1 Summary of comparative catalytic experiment results of nano yttrium carbonate products prepared in the examples of the present invention and commercially available nano yttrium carbonate products

[0106] Test item Product 1 Product 2 Product 3 Product 4 Product 5 Total liquid recovery 73.56 73.42 73.51 69.39 69.29 Conversion rate 81.74 81.68 81.70 78.10 77.74

[0107] Table 1 shows that:

[0108] Overall, the total liquid yields and conversion rates of products 1, 2, and 3 all reflect significantly better catalytic performance than the commercially available products 4 and 5; especially for product 1, because its structure helps to reduce the agglomeration between particles and improve the utilization rate of the catalyst. At the same time, the curvature of the spherical surface enables reactant molecules to be more easily adsorbed and desorbed, thus accelerating the catalytic reaction rate.

[0109] A large number of particulate morphologies are mixed in the commercially available products, and there are problems such as uneven size distribution and relatively large particle size. This phenomenon of morphological heterogeneity and poor size dispersion leads to uneven dispersion of the catalyst on the carrier surface and discontinuous distribution of active sites, thereby reducing the specific surface area and surface energy of the catalyst and affecting its catalytic activity and use efficiency.

[0110] Comparative Example 2

[0111] (1) Dissolve yttrium chloride hexahydrate in water to obtain a yttrium chloride solution with a mass concentration of 100 g / L; then mix the yttrium chloride solution and the (NH4)2S solution (with a concentration of 15 g / L), and heat and stir at 60 °C for 30 min with a stirring speed of 300 rap / min to obtain a high-purity yttrium chloride solution with a mass fraction of 90%.

[0112] (2) Dissolve a certain mass of sodium carbonate in water and heat to obtain a precipitant solution at 60 °C with a mass concentration of 300 g / L.

[0113] (3) Dissolve the surfactant SDS in water and heat to obtain a surfactant solution at 60 °C; among them, the dosage of SDS is 0.05% of the dosage of yttrium chloride.

[0114] (4) Pump the yttrium chloride solution prepared in step (1) and the precipitant solution prepared in step (2) into a multiphase interface reactor for liquid-phase precipitation reaction to obtain nano yttrium carbonate slurry; the flow rates of the yttrium chloride solution and the precipitant solution are 250 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 1000 rpm.

[0115] (5) Pump the surfactant solution prepared in step (3) and the nano yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size regulation to obtain a nano yttrium carbonate precursor suspension; the flow rates of the surfactant solution and the nano yttrium carbonate slurry are 200 mL / min and 300 mL / min respectively, and the rotation speed of the multiphase interface reactor is 1000 rpm.

[0116] (6) Age the nano yttrium carbonate suspension prepared in step (5) (at 80 °C for 2 h), filter (using a Buchner funnel for pressure filtration with a pressure of 0.08 Mpa), wash (by suction filtration with a solid-liquid ratio of 6:1), dry (at 80 °C for 12 h), and pulverize (using a multi-functional pulverizer for 3 min) to obtain nano yttrium carbonate powder, referring to Figure 4 .

[0117] The washing condition is that the conductivity of the filtrate is less than 100 μs / cm.

[0118] Compare Figure 1 and Figure 4 The product obtained in Comparative Example 2 has an irregular morphology and uneven particle size distribution.

[0119] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nano-yttrium carbonate, characterized in that: The particle size of the nano yttrium carbonate is 40-120nm.

2. Nano-yttrium carbonate as claimed in claim 1, characterized in that, The microscopic morphology of the nano-yttrium carbonate is spherical, and the particle size is 40-60nm.

3. Nano-yttrium carbonate as claimed in claim 1, characterized in that, The microscopic morphology of the nano-yttrium carbonate is flake-shaped, and the particle size is 40-70nm.

4. Nano-yttrium carbonate as claimed in claim 1, characterized in that, The microscopic morphology of the nano-yttrium carbonate is rod-shaped, and the particle size is 90-120nm.

5. A method for preparing nano-yttrium carbonate with controllable morphology, for preparing the nano-yttrium carbonate described in any one of claims 1 to 4, characterized in that: The following steps are involved: (1) dissolving yttrium chloride hexahydrate in water to obtain a yttrium chloride solution, and then mixing the yttrium chloride solution and (NH4)2S solution, heating and stirring, to obtain a high-purity yttrium chloride solution; (2) preparing a precipitant solution at a certain temperature, wherein the precipitant is at least one of sodium carbonate, ammonium carbonate, and ammonium bicarbonate; (3) preparing a surfactant solution at a certain temperature, wherein the surfactant is at least one of SDS, SDBS, PVP, and PEG4000; (4) pumping the yttrium chloride solution obtained in step (1) and the precipitant solution obtained in step (2) into a multiphase interface reactor for liquid phase precipitation reaction to obtain a nano-yttrium carbonate slurry, wherein the flow rates of the yttrium chloride solution and the precipitant solution are both 200-500 mL / min, the rotation speed of the multiphase interface reactor is 3000-4500 rpm, and the molar ratio of yttrium chloride to the precipitant is 1:1.6-1:3.0; (5) pumping the surfactant solution prepared in step (3) and the nano-yttrium carbonate slurry prepared in step (4) into a multiphase interface reactor for particle size control to obtain a nano-yttrium carbonate precursor suspension, wherein the flow rates of the surfactant solution and the nano-yttrium carbonate slurry are both 250-450 mL / min, and the rotation speed of the multiphase interface reactor is 2000-4500 rpm; (6) aging, filtering, washing, drying and crushing the nano-yttrium carbonate suspension obtained in step (5) to obtain nano-yttrium carbonate powder.

6. The preparation method of nano-yttrium carbonate with controlled morphology as claimed in claim 5, characterized in that, The dosage of the surfactant is 0.01%-0.5% of the dosage of yttrium chloride.

7. The preparation method of nano-yttrium carbonate with controlled morphology as claimed in claim 5, characterized in that, Preparation of spherical nano-yttrium carbonate: The surfactants in step (3) are SDS and PEG4000, and the amounts of SDS and PEG4000 are 0.5% and 0.05% of the amount of yttrium chloride, respectively; In step (4), the flow rates of the yttrium chloride solution and the precipitant solution pumped into the multiphase interface reactor are 300 mL / min and 450 mL / min respectively; the rotation speed of the multiphase interface reactor is 3500 rpm; In step (5), the surfactant solution and the nano-yttrium carbonate slurry are pumped into the multiphase interface reactor at flow rates of 400 mL / min and 450 mL / min respectively; the rotation speed of the multiphase interface reactor is 3500 rpm.

8. The preparation method of nano-yttrium carbonate with controlled morphology as claimed in claim 5, characterized in that, Preparation of flake-like nano-yttrium carbonate: The surfactant in step (3) is SDS, and the amount of SDS is 0.5% of the amount of yttrium chloride; In step (4), the flow rates of the yttrium chloride solution and the precipitant solution pumped into the multiphase interface reactor are 300 mL / min and 400 mL / min respectively; the rotation speed of the multiphase interface reactor is 3500 rpm; In step (5), the surfactant solution and the nano-yttrium carbonate slurry are pumped into the multiphase interface reactor at flow rates of 250 mL / min and 300 mL / min respectively; the rotation speed of the multiphase interface reactor is 3000 rpm.

9. The preparation method of nano-yttrium carbonate with controlled morphology as claimed in claim 5, characterized in that, Preparation of rod-shaped nano-yttrium carbonate: The surfactants in step (3) are PVP and PEG4000, and the amounts of PVP and PEG are 0.5% and 0.05% of the amount of yttrium chloride, respectively; In step (4), the flow rates of the yttrium chloride solution and the precipitant solution pumped into the multiphase interface reactor are 450 mL / min and 300 mL / min respectively; the rotation speed of the multiphase interface reactor is 4000 rpm; In step (5), the surfactant solution and the nano-yttrium carbonate slurry are pumped into the multiphase interface reactor at flow rates of 300 mL / min and 300 mL / min respectively; the rotation speed of the multiphase interface reactor is 2500 rpm.

10. An application of nano yttrium carbonate, wherein the nano yttrium carbonate described in claim 1 is applied to the field of heavy oil cracking catalysis.

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