WO2008083563A1 - A microsphere of layered double hydroxide and method for preparing the same - Google Patents

Abstract

Disclosed are a microsphere of layered double hydroxide and method for preparing the same. The method comprises the steps of preparing particles of layered double hydroxide (hydrotalcite-like compound) having a nano-sized or submicron-sized particle size, making the hydrotalcite-like compound into a slurry with an amount of solid content, adding appropriate binders to the slurry so as to obtain a colloidal slurry suitable for spray drying, and granulating and drying the colloidal slurry with a rotary spray dryer, thereby obtaining the microspheres having a particle size of 5-100 μm, a bulk density of 0.4-0.8 g/cm3, a specific surface area of 40-150 m2/g, a pore volume of 0.1-0.8 cm3/g and most probable pore size of 2-40 nm. The microspheres can be directly used to fields of catalysis and separation without shaping due to its spherical shape and its pore size distribution that is within the scope of mesopores, and can reduce the resistance of mass transfer and the deposition of carbon.

Description

 Layered bishydroxy composite metal oxide microsphere and preparation method thereof

 The invention relates to a layered bishydroxy composite metal oxide microsphere and a preparation method thereof, and particularly relates to a molding process of a nanometer or submicron layered bishydroxy composite metal oxide particle having strong rigidity as a building unit. Granule method. Background technique

 Hydrotalcite-like compounds include hydrotalcite and hydrotalcite-like compounds, and the main body thereof is generally composed of hydroxides of two metals, so it is also called layered double-hydroxy composite metal oxide (Layered Double Hydroxide). , abbreviated as LDH). The intercalated compound of LDH is called intercalated hydrotalcite. Hydrotalcite, hydrotalcite-like, and intercalated hydrotalcite are collectively referred to as hydrotalcite-like intercalation materials (LDHs:). The material is a hexagonal sheet structure, and the sheet itself has extremely high rigidity, and it is extremely difficult to prepare a sheet-like structure with controllable morphology. This type of material is an inorganic material with unique structural properties: such as tunable denaturation of elemental composition over a wide range, tunable denaturation of pore structure, and designability of interlayer anion species, etc. It is likely to be the basis for industrial catalysts or catalyst precursors with potential applications. In particular, when such materials are calcined at a high temperature, the metal cations of the laminate can be converted into a composite metal oxide having a spinel structure uniformly dispersed on a molecular scale. Therefore, we can pass the species and ratio of the metal cations on the laminate. Etc. is designed to obtain a catalyst or catalyst support having specific catalytic properties.

It is well known that in catalytic applications, the catalyst often needs to be formed before it can be used. On the one hand, it is beneficial to increase the mechanical strength of the catalyst, on the other hand, it is beneficial to the separation and recovery of the catalyst and reuse. However, in the literature, the hydrotalcite-like material is used. When the catalyst precursor is used, the powder material is used. Therefore, molding such a highly rigid hydrotalcite-like material will certainly improve the catalytic effect of the catalyst and the separation and recovery of the heterogeneous catalyst. When the catalyst is molded, it is often necessary to add a certain proportion of the binder to achieve the purpose of auxiliary molding. Adhesives are a general term for a class of non-metallic materials that bond a solid surface to another solid surface by means of surface bonding and internal forces (adhesion and cohesion, etc.). These materials are mainly composed of a raw material capable of bonding, supplemented by a solvent, a plasticizer, a tackifier, a crosslinking agent, a curing agent, a penetrating agent, a filler, etc., by physical, chemical or a combination of the two. The method is formulated into a complex mixture system capable of bonding at the interface of two objects.

 In the literature /· Am. Chem. Soc. 2002, 124 (47): 14127-14136, Choudary B.

M. et al. studied the Heck-, Suzuki-, Sonogashira- and Stille- reactions of chlorinated aromatic compounds catalyzed by a layered bishydroxy-complex metal oxide as a support (or basic ligand). Excellent performance for catalyzing the C-C coupling reaction.

 In the literature Chem. Int. Edit. 2001, 40 (4): 763-766, Choudary BM et al. first studied the product of NiAlLDHs after rehydration activation in the presence of molecular oxygen, which can be catalyzed under mild conditions. The alcoholic compound of allyl, benzyl or alpha keto alcohol is converted into a carbonyl compound, and it is pointed out that this process is not only economically feasible but also suitable for large-scale reactions.

 In the literature React. Kinet. Catal. Lett. 2000, 69 (2): 223-229, Das, and

Parida, K. studied the activity of different Ζη/Α1 hydrotalcite-like materials after calcination at 450 °C, showing good activity in catalyzing the ketone formation of acetic acid.

 In the above documents, the hydrotalcite-like material exhibits a good catalytic effect as a catalyst precursor, however, such materials are added in the form of powders at the time of use, which brings about separation and recovery of the catalyst after the completion of the reaction. negative effect. Therefore, the preparation of hydrotalcite-like materials will certainly facilitate the separation and recycling of the catalyst. Summary of the invention

The object of the present invention is to provide a layered bishydroxy composite metal oxide microsphere and a preparation method thereof, that is, a nanometer or submicron layered bishydroxy composite metal oxide particle having a relatively high rigidity The building unit, with the binder as the auxiliary material, realizes the direct preparation of the layered bishydroxy composite metal oxide material in the form of microspheres for the first time by using the common industrial spray drying equipment. Firstly, the preparation method of common hydrotalcite-like materials such as coprecipitation, nucleation crystallization/isolation, non-equilibrium crystallization or hydrothermal synthesis is used to prepare the layer size of nanometer or submicron. The bishydroxy composite metal oxide (hydrotalcite-like) particles are then formulated into a colloidal slurry of different binder content and solid content by adjusting the amount of binder and water added, and finally the colloidal slurry is used as the starting material. The preparation of materials in the form of microspheres is achieved on industrial spray drying equipment. The material can be directly used in the field of catalysis or separation after activation, without the need for a re-forming stage, and the excellent pore structure can reduce the mass transfer resistance and reduce the occurrence of carbon deposition.

 The layered bishydroxy composite metal oxide microsphere provided by the present invention, the chemical formula of the layered bishydroxy complex metal oxide is:

[Μ ^π _1-x M ^m _x (OH) ₂ ] ^x+ -(A ⁿ -)x/n-mH ₂ 0

Wherein M ¹¹ is one or two of Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Cu ²⁺ , Co ²⁺ , Ca ²⁺ and Fe ²⁺ , and M ^m is Al ³⁺ , Cr ³⁺ Any one or two of Ga ³⁺ , In ³⁺ , Co ³⁺ , Fe ³⁺ and V ³⁺ , A ⁿ - is C0 ₃ ² —, N0 ₃ , S0 ₄ ² , Cl—, F— And one or more of Br-, x is 0.2-0.33, n is the valence state of anion A, m is 0-6;

The microspheres have a particle diameter of 5 to 100 μπι, an average particle diameter d( ₅ )=20 to 25 μπι, a bulk density of 0.4-0.8 g/cm ³ , and a specific surface area of 20 to: 150 m ² /g. Between, the pore volume is between 0.1 and 0.8 cm ³ /g, and the most suitable pore size is between 2 and 40 nm; the microsphere is a solid sphere.

 The preparation method of the layered bishydroxy composite metal oxide microsphere provided by the invention comprises the following steps:

A. Preparing a nano- or sub-micron layered bishydroxy-complex metal oxide having a chemical formula of: [M ¹¹ _1-x M ^m _x (OH) ₂ ] ^x+ -( A ⁿ -)x/n-mH ₂ 0

Wherein M ¹¹ is one or two of Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Cu ²⁺ , Co ²⁺ , Ca ²⁺ and Fe ²⁺ , and M ^m is Al ³⁺ , Cr ³⁺ Any one or two of Ga ³⁺ , In ³⁺ , Co ³⁺ , Fe ^{3+ ,} and V ³⁺ , A ⁿ - is one or more of C0 ₃ ² —, N0 ₃ , S0 ₄ ² , Cl—, F— and Br—, x is 0.2-0.33, n is the valence state of anion A, and m is 0- 6;

 B. The layered bishydroxy composite metal oxide prepared in step A is thoroughly washed with deionized water to make the pH of the supernatant liquid 7-8, and then fully stirred by adding deionized water to prepare a solid content of 1~ 20% of the slurry;

 C. Adding 0.5 to 10% of the total weight of the slurry to the slurry of the step B, and stirring sufficiently to make the system uniform in a colloidal state;

 The binder used may be a natural binder such as starch, protein, dextrin, animal glue or the like, or a synthetic binder such as synthetic resin, polyvinyl alcohol, water glass or the like;

 D. The colloidal slurry obtained in step C is spray dried.

 In the step A, the nano- or sub-micron layered bishydroxy complex metal oxide can be prepared by a conventional method in the art, for example, coprecipitation, nucleation/crystallization separation, non-equilibrium crystallization Method or hydrothermal synthesis. The preferred method is nucleation/crystallization crystallization, which is nucleated using a full anti-mixed membrane reactor (see CN 1358691A) and then crystallized by a programmed temperature-controlled crystallization method (see CN 1358692A). The method can obtain a nano- or sub-micron layered bishydroxy-complex metal oxide with a narrow distribution.

 In the step D, the method of spray drying is preferably that the colloidal slurry obtained by the step C is driven into the atomizing wheel of the rotary spray dryer at a flow rate of 1 to 30 mL/min by a constant flow pump to adjust the mist. The rotation speed of the wheel is between 1.0 and 20,000 rpm, and the temperature at the inlet of the spray drying is between 110 ° C and 180 ° C. The preferred operating conditions are: the speed of the atomizing wheel is 1.2 to 15,000 rpm, the feed rate is 5 to 20 mL/min, and the inlet temperature is between 140 °C and 160 °C.

A remarkable feature of the present invention is that microspheres having a layered bishydroxy composite metal oxide fine particle having a relatively high rigidity as a building unit are prepared for the first time by the action of a binder. The layered bishydroxy composite metal oxide microspheres are prepared by the method provided by the invention, and the preparation method thereof is simple and convenient, and is suitable for industrialization. DRAWINGS

 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an XRD spectrum of microspheres prepared in Examples 1, 2, 3, 4 and 5, wherein Id is a characteristic spectrum of Examples 4 and 5;

 2 is a progressive SEM image and a cross-sectional BSEM image of the microspheres obtained in Example 1. FIG. 3 is a step-by-step SEM image and a cross-sectional BSEM image of the microspheres obtained in Example 4. FIG. A stepwise magnified SEM image and a cross-sectional BSEM image of the obtained microspheres; FIG. 5 is a progressive SEM image of the microspheres prepared in Example 9;

 Figure 6 is a progressive SEM image of the microspheres prepared in Example 10;

 Figure 7 is a progressive SEM image of the microspheres prepared in Example 11;

 Figure 8 is a progressive SEM image of the microspheres prepared in Example 13. detailed description

 The present invention will be further described below in conjunction with the embodiments:

In the following examples, the particle size, the average particle diameter d ( _{Q. 5} ), the bulk density, the specific surface area, the pore volume, and the most achievable pore diameters were determined by the following methods, respectively:

Particle size and average particle diameter d( ₅ ): observed by SEM;

 Bulk density: The volume and mass (m) of the product are measured by a graduated cylinder and an analytical balance, respectively, and the bulk density is p=m/V;

 Specific surface area, pore volume and most pore size: Measured by low temperature nitrogen absorption and desorption methods. Example 1

A: Weigh 61.54 g Mg(N0 ₃ ) ₂ -6H ₂ 0 and 45.02 g Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0 dissolved in deionized water to prepare 300 mL mixed salt solution; then weigh 23.04 g NaOH and 25.44 g Na ₂ C0 _{3 was} dissolved in deionized water to prepare 300 mL of mixed alkali solution; the above two mixed solutions were simultaneously added to the full back-mixed membrane reactor, and the slit width between the reactor rotor and the stator was adjusted to 0.02 mm. Work The voltage is 100 V, the rotor rotation speed is 4000 rpm, and the obtained mixed slurry is added to the crystallization tank for stirring, and the temperature of the mixed slurry in the autoclave is maintained at 95-105 Torr for refluxing for 6 hours to obtain a magnesium-aluminum hydrotalcite;

 B: The product prepared in the step A is thoroughly washed with deionized water, and the pH of the supernatant is 7 8 and further stirred with deionized water to prepare a slurry having a solid content of 2%;

 C: adding 1% of PVA to the hydrotalcite-like slurry of step B, and stirring thoroughly to make the system uniformly colloidal;

D: The colloidal slurry of step C was driven into the atomizing wheel at a speed of 6 10 mL/min with a constant flow pump at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying was set to 150 °. C, spray granulation; the obtained spherical particles have a particle diameter of ₅ to 60 μm, an average particle diameter d( ₅ ) of 20 μm, a bulk density of 0.4 g/cm ³ and a specific surface area of 39.76 m ² /g, total pores The volume is 0.31mL/g, and the most pore size is 32.5 nm. Example 2

 A: Same as Embodiment 1;

 B: same as embodiment 1;

 C: adding PVA of 5% of the total weight of the slurry to the hydrotalcite-like slurry of step B, and stirring sufficiently to make the system uniformly colloidal;

D: The colloidal slurry of step C was driven into the atomizing wheel at a speed of 6 10 mL/min with a constant flow pump at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying was set to 150 °. C, spray granulation. The obtained spherical particles have a particle diameter of 10 to 80 μm, an average particle diameter d( ₅ ) of 22 μm, a bulk density of 0.55 g/cm ³ , a specific surface area of 30.27 m ² /g, and a total pore volume of 0.28 mL/g. The most suitable aperture is 30.1 Example 3

 A: Same as Embodiment 1;

 B: same as embodiment 1;

 C: adding PVA to 10% of the total weight of the slurry to the hydrotalcite-like slurry of step B, and thoroughly stirring to make the system uniformly colloidal;

D: The colloidal slurry of step C was driven into the atomizing wheel at a speed of 6 10 mL/min with a constant flow pump at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying was set to 150 °. C, spray granulation. The obtained spherical particles have a particle diameter of 20 to 100 μm, an average particle diameter d( ₅ ) of 40 μm, a bulk density of 0.8 g/cm ³ , a specific surface area of 20.56 m ² /g, and a total pore volume of 0.12 mL/g. The most probable aperture is 13.5 nm. Example 4

A: Weigh 71.39 g Ζη(Ν0 ₃ ) ₂ ·6Η ₂ 0 and 45.02 g Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0 Dissolve in 300 mL of mixed salt solution in deionized water; then weigh 23.04 g NaOH and 25.44 g Na ₂ C0 _{3 was} dissolved in deionized water to prepare 300 mL mixed salt solution; nucleation crystallization conditions were the same as in Example 1, to prepare zinc-aluminum hydrotalcite;

 B: The product prepared in the step A is thoroughly washed with deionized water, and the pH of the supernatant is 7 8 and further stirred with deionized water to prepare a slurry having a solid content of 2.5%;

 C: adding soluble starch of 5% by weight of the total slurry to the hydrotalcite-like slurry of step B, and stirring uniformly to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 10 mL/min onto an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150 °. C, spray granulation; the obtained spherical particles have a particle diameter of 10 to 60 μm, an average particle diameter d( ₅ ) of 40 μm, a bulk density of 0.67 g/cm ³ and a specific surface area of 25.45 m ² /g, total pores The capacity is 0.16mL/g, and the most suitable pore size is 32.6. Example 5

 A: same as embodiment 4;

 B: same as embodiment 4;

 C: adding 10% of the total weight of the soluble starch to the hydrotalcite-like slurry of step B, and stirring sufficiently to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 to 10 mL/min to an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150. At ° C, spray granulation was carried out. The obtained spherical particles have a particle diameter of 15-85 μm, an average particle diameter d( ₅ ) of 50 μm, a bulk density of 0.76 g/cm ³ , a specific surface area of 17.23 m ² /g, and a total pore volume of 0.11 mL/ _g . The most suitable aperture is 26.4 匪. Example 6

A: Weigh 69.79 g Ni(N0 ₃ ) ₂ -6H ₂ 0 and 45.02 g Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0 dissolved in deionized water to prepare 300 mL mixed salt solution; then weigh 28.80 g NaOH and 25.44 g Na ₂ C0 _{3 was} dissolved in deionized water to prepare 300 mL mixed salt solution; nucleation and crystallization conditions were the same as in Example 1 to prepare nickel aluminum hydrotalcite;

 B: The product prepared in the step A is thoroughly washed with deionized water, and the pH of the supernatant is 7-8, and the mixture is thoroughly stirred with deionized water to prepare a slurry having a solid content of 3%;

 C: adding 1% of PVA to the hydrotalcite-like slurry of step B, and stirring thoroughly to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 to 10 mL/min to an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150. °C, spray granulation; the obtained spherical particles have a particle diameter of 5-60 μm, an average particle diameter d( ₅ ) of 30 μm, a bulk density of 0.41 g/cm ³ and a specific surface area of 111.37 m ² /g. The pore volume is 0.62 mL/ _g , and the most porous pore size is 18.13 匪. Example 7

 A: same as embodiment 6;

 B: same as embodiment 6;

 C: adding PVA of 5% of the total weight of the slurry to the hydrotalcite-like slurry of step B, and thoroughly stirring to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 to 10 mL/min to an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150. At ° C, spray granulation was carried out. The obtained spherical particles have a particle diameter of 20 to 80 μm, an average particle diameter d( ₅ ) of 40 μm, a bulk density of 0.50 g/cm ³ , a specific surface area of 98.78 m ² /g, and a total pore volume of 0.53 mL/g. The most probable aperture is 14.59 nm. Example 8

 A: same as embodiment 6;

 B: same as embodiment 6;

 C: adding PVA to 10% of the total weight of the slurry to the hydrotalcite-like slurry of step B, and thoroughly stirring to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 to 10 mL/min to an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150. At ° C, spray granulation was carried out. The obtained spherical particles have a particle diameter of 40 to 100 μm, an average particle diameter d( ₅ ) of 60 μm, a bulk density of 0.76 g/cm ³ , a specific surface area of 75.12 m ² /g, and a total pore volume of 0.47 mL/g. The most probable aperture is 12.88 nm. Example 9

A: Weigh 19.33 g Οι(Ν0 ₃ ) ₂ ·63⁄40, 47.6 g Ζη(Ν0 ₃ ) ₂ ·6Η ₂ 0 and 45.02 g Al N0 ₃ 93⁄40 dissolved in deionized water to prepare 300 mL mixed salt solution; 28.80 g NaOH and 25.44 g of Na ₂ C0 _{3 were} dissolved in deionized water to prepare 300 mL of mixed alkali solution; the nucleation conditions were the same as in Example 1, and the crystallization was carried out under normal pressure at room temperature for 12 hours to prepare copper, zinc and aluminum. Meta-type hydrotalcite;

 B: The product prepared in the step A is thoroughly washed with deionized water, and the pH of the supernatant is 7 8 and further stirred with deionized water to prepare a slurry having a solid content of 4%;

 C: adding 1% of PVA to the hydrotalcite-like slurry of step B, and stirring thoroughly to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 10 mL/min onto an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150 °. C, spray-drying granulation; the obtained spherical particles have a particle diameter of ₅ to 50 μm, an average particle diameter d( ₅ ) of 30 μm, a bulk density of 0.55 g/cm ³ , and a specific surface area of 90.6 m ² /g, total pores The capacity is 0.65mL/g, and the most suitable pore size is 32. Example 10

A: Weigh 21.74 g Cu(N0 ₃ ) ₂ '63⁄40 53.55 g Ζη(Ν0 ₃ ) ₂ ·63⁄40 and 33.76 g Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0 dissolved in deionized water to prepare 300 mL mixed salt solution Further weighed 28.80 g NaOH and 19.08 g Na ₂ C0 ₃ dissolved in deionized water to prepare 300 mL mixed alkali solution; nucleation and crystallization conditions were the same as in Example 9, to prepare copper zinc aluminum ternary hydrotalcite;

 B: The product prepared in the step A is thoroughly washed with deionized water, the pH of the supernatant is 7 8 , and the slurry is fully stirred with deionized water to prepare a slurry having a solid content of 5%;

 C: adding soluble starch of 5% by weight of the total slurry to the hydrotalcite-like slurry of step B, and stirring sufficiently to make the system uniformly colloidal;

D: The colloidal slurry of step C was driven into the atomizing wheel at a speed of 6 10 mL/min with a constant flow pump at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying was set to 150 °. C, spray-drying granulation; the obtained spherical particles have a particle diameter of 10-60 μm, and the average particle diameter d( ₅ ) is 40 μm The bulk density was 0.67 g/cm ³ , the specific surface area was 91.81 m ² /g, the total pore volume was 0.70 mL/g, and the most pore diameter was 33.6 Å. Example 11

A: Weigh 30.77 g M _g (N0 ₃ ) ₂ '63⁄40 and 22.51 g Α1 (Ν0 ₃ ) ₃ ·9Η ₂ 0 dissolved in deionized water to prepare 300 mL mixed salt solution; weigh 14.4 g NaOH and 3.18 g Na ₂ C0 _{3 is} dissolved in deionized water to prepare 300 mL mixed alkali solution; at a stirring speed of 500 rpm, the mixed salt solution is added dropwise to the mixed alkali solution; or the mixed alkali solution is added dropwise to the mixed solution. In the salt solution, the controlled dropping rate is 10 mL/min, the pH value of the end point is controlled between 9.5 and 10, and then crystallized at 65 °C for 12 hours to prepare a magnesium-aluminum hydrotalcite material;

 B: The product prepared in the step A is thoroughly washed with deionized water, the pH of the supernatant is 7-8, and the slurry is fully stirred with deionized water to prepare a slurry having a solid content of 2%;

 C: adding 1% of PVA to the hydrotalcite-like slurry of step B, and stirring thoroughly to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 to 10 mL/min to an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150. At ° C, spray granulation was carried out. The obtained spherical particles have a particle diameter of ₅ to 60 μm, an average particle diameter d( ₅ ) of 40 μm, a bulk density of 0.51 g/cm ³ , a specific surface area of 126.45 m ² /g, and a total pore volume of 0.71 mL/g. The most probable aperture is 20.64 匪. Example 12

A: Weigh 30.77 g M _g (N0 ₃ ) ₂ '63⁄40 and 22.51 g Α1 (Ν0 ₃ ) ₃ ·9Η ₂ 0 dissolved in deionized water to prepare 300 mL mixed salt solution; weigh 14.4 g NaOH and 3.18 g Na ₂ C0 _{3 was} dissolved in deionized water to prepare 300 mL of mixed alkali solution; at the stirring speed of 500 rpm, the above two mixed solutions were simultaneously added dropwise to a 1 L three-necked flask containing 100 mL of deionized water. Drop acceleration The degree is 5mL / min; the pH value is always controlled between 9.5 10, and then crystallized at 65 ° C for 12 hours to prepare a magnesium-aluminum hydrotalcite material;

 B: The product prepared in the step A is thoroughly washed with deionized water, and the pH of the supernatant is 7 8 and further stirred with deionized water to prepare a slurry having a solid content of 2%;

 C: PVA is added to the hydrotalcite-like slurry of step B by 1% by weight of the total slurry, and the mixture is thoroughly stirred to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 10 mL/min onto an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150 °. C, spray granulation. The obtained spherical particles have a particle diameter of 10 to 60 μm, an average particle diameter d( ₅ ) of 40 μm, a bulk density of 0.53 g/cm ³ , a specific surface area of 123.59 m ² /g, and a total pore volume of 0.74 mL/g. The most probable aperture is 35.65. Example 13

A: Weigh 61.54 g Mg(N0 ₃ ) ₂ '63⁄40 31.51 g Α1(Ν0 ₃ ) ₃ ·93⁄40 and 12.78 g Ιη(Ν0 ₃ ) ₃ ·33⁄40 dissolved in deionized water to prepare 300 mL mixed salt solution; 23.04 g NaOH and 25.44 g Na ₂ C0 _{3 were} dissolved in deionized water to prepare 300 mL mixed alkali solution; nucleation and crystallization conditions were the same as in Example 1, to prepare magnesium aluminum indium ternary hydrotalcite;

 B: The product prepared in the step A is thoroughly washed with deionized water, and the pH of the supernatant is 7 8 and further stirred with deionized water to prepare a slurry having a solid content of 2%;

 C: adding PVA of 1% of the total weight of the slurry to the hydrotalcite-like slurry of step B, and stirring thoroughly to make the system uniformly colloidal;

D: The colloidal slurry of step C is driven by a constant current pump at a flow rate of 6 10 mL/min to an atomizing disk rotating at a speed of 12,000 rpm, and the temperature at the inlet of the spray drying is set to 150 °. C, spray granulation. The spherical particles obtained have a particle diameter of 20-80 μm, an average particle diameter d( ₅ ) of 60 μπι, a bulk density of 0.69 g/cm ³ , a specific surface area of 105.21 m ² /g, and a total pore volume of 0.62 mL/g. a few The pore size is 30.57 nm. The spherical material prepared in the above examples was qualitatively analyzed by Shimadu XRD-6000 powder X-ray diffractometer. The results are as follows:

 Figure 1 is an XRD spectrum of the obtained material, wherein la, lb and lc are the spectra of the samples of Examples 1, 2, 3 and 4, respectively, and (003), (006) of the hydrotalcite-like materials are visible from the figure. The characteristic peaks of (012), (015), (110) and (113) appear, indicating that the obtained material is a layered bishydroxy composite metal oxide.

(hydrotalcite-like).

 The samples prepared by the above examples of Hitachi-S3500N SEM were used for morphology analysis. The results are as follows:

 2 is a SEM image of a microsphere obtained by using MgAlLDHs as a building unit obtained by using a colloidal slurry containing 1% PVA and 2% solid content, wherein 2a-c is a step-by-step enlarged image of the sample, as can be seen from the figure. The obtained microspheres have good sphericity; FIG. 2d is a cross-sectional view of the microspheres obtained by back-scattering scanning electron imaging (BSEM) after being subjected to resin embedding of the microspheres, and the results show that the microspheres are obtained. The ball is a solid ball.

 3 is a SEM image of a microsphere obtained by using ZnAlLDHs as a building unit obtained in Example 4, which contains a 5% soluble starch and a 2.5% solid content colloidal slurry, wherein 3a-c is a step-by-step enlarged image of the sample, which can be seen from the figure. The prepared microspheres have good sphericity; FIG. 3d is a cross-sectional view of the microspheres obtained by back-scattering scanning electron imaging (BSEM) after resin-embedded microspheres, and the results show that the obtained microspheres are obtained. The microspheres are solid balls.

4 is a SEM image of a microsphere obtained by using NiAlLDHs as a building unit obtained by using a colloidal slurry containing 1% PVA and 3% solid content in Example 6, wherein 4a-c is a step-by-step enlarged image of the sample, as shown in the figure, The obtained microspheres have good sphericity; FIG. 4d is a cross-sectional view of the microspheres obtained by back-scattering scanning electron imaging (BSEM) after resin-embedded microspheres, and the results show that the prepared microspheres are obtained. For the solid ball. 5 is a SEM image of a microsphere obtained by using CuZnAlLDHs (Cu: Zn: Al=l: 2: 1.5) as a building unit obtained by using a colloidal slurry containing 1% PVA and 4% solid content in Example 9, wherein 5a-b For the progressive enlargement of the sample, it can be seen from the figure that the prepared microspheres have good sphericity.

 6 is a SEM image of a microsphere obtained by using CuZnAlLDHs (Cu: Zn: Al=l: 2:1) as a building unit obtained in Example 10 with a 5% soluble starch and a 5% solid content colloidal slurry, wherein 6a- b is a step-by-step enlargement of the sample. As can be seen from the figure, the prepared microspheres have good sphericity.

 7 is a SEM image of a microsphere obtained by using MgAlLDHs as a building unit obtained by using a colloidal slurry containing 1% PVA and 2% solid content, wherein 7a-b is a step-by-step enlarged image of the sample, as shown in the figure, The prepared microspheres have good sphericity.

 Figure 8 is a sample 13 obtained by using a colloidal slurry containing 1% PVA and 2% solids.

MgAlInLDHs is the SEM image of the microspheres of the building unit, and 8a-b is a step-by-step enlarged image of the sample. It can be seen from the figure that the prepared microspheres have good sphericity.

Claims

Claim A layered bishydroxy composite metal oxide microsphere, the chemical formula of the layered bishydroxy complex metal oxide is: [Μ ^π _1-x M ^m _x (OH) ₂ ] ^x+ -(A ⁿ -)x/n-mH ₂ 0 Wherein M ¹¹ is one or two of Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Cu ²⁺ , Co ²⁺ , Ca ²⁺ and Fe ²⁺ , and M ^m is Al ³⁺ , Cr ³⁺ Any one or two of Ga ³⁺ , In ³⁺ , Co ³⁺ , Fe ³⁺ and V ³⁺ , A ⁿ - is C0 ₃ ² —, N0 ₃ , S0 ₄ ² , Cl—, F— And one or more of Br-, x is 0.2-0.33, n is the valence state of anion A, m is 0-6; The microspheres have a particle diameter of 5 to 100 μπι, an average particle diameter d( ₅ )=20 to 25 μπι, a bulk density of 0.4-0.8 g/cm ³ , and a specific surface area of 20 to: 150 m ² /g. Between, the pore volume is between 0.1 and 0.8 cm ³ /g, and the most suitable pore size is between 2 and 40 nm; the microsphere is a solid sphere. 2. A method of preparing a layered bishydroxy-complex metal oxide microsphere according to claim 1, the method comprising the steps of: A. Preparing a nano- or sub-micron layered bishydroxy-complex metal oxide having a chemical formula of: [M ¹¹ _1-x M ^m _x (OH) ₂ ] ^x+ -( A ⁿ -)x/n-mH ₂ 0 Wherein M ¹¹ is one or two of Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Cu ²⁺ , Co ²⁺ , Ca ²⁺ and Fe ²⁺ , and M ^m is Al ³⁺ , Cr ³⁺ Any one or two of Ga ³⁺ , In ³⁺ , Co ³⁺ , Fe ³⁺ and V ³⁺ , A ⁿ - is C0 ₃ ² —, N0 ₃ , S0 ₄ ² , Cl—, F— And one or more of Br-, x is 0.2-0.33, n is the valence state of anion A, m is 0-6;  B. The layered bishydroxy composite metal oxide prepared in the step A is thoroughly washed with deionized water, the pH of the supernatant is 7-8, and the mixture is fully stirred by adding deionized water to prepare a solid content of 1 ~ 20% of the slurry; C. Adding 0.5~10% of the total weight of the slurry to the slurry of the step B, stirring well The system is in a uniform colloidal state, and the binder is one of starch, protein, dextrin, animal glue, synthetic resin, polyvinyl alcohol and water glass;  D. The colloidal slurry obtained in step C is spray dried. The method for producing a layered bishydroxy composite metal oxide microsphere according to claim 2, wherein in the step A, the layered bishydroxy composite metal oxide is formed by coprecipitation, nucleation/ Prepared by crystallization isolation, non-equilibrium crystallization or hydrothermal synthesis. The method for preparing a layered bishydroxy composite metal oxide microsphere according to claim 2, wherein the method of spray drying in step D comprises using a constant flow pump to obtain a colloidal slurry obtained by the step C to 1~ The flow rate of 30 mL/mm is driven into the atomizing wheel of the rotary spray dryer. The spray drying conditions are: The speed of the atomizing wheel is 1.0~200,000 rpm, and the temperature at the inlet of the spray drying is 110 °C~180 °. Between C. The method for preparing a layered bishydroxy composite metal oxide microsphere according to claim 4, wherein the spray drying condition of the step D is: the rotation speed of the atomizing wheel is 1.2 to 15,000 rpm, and the feeding speed is For 5~20 mL/min, the inlet temperature is between 140 °C and 160 °C.