CN114602494B

CN114602494B - Method for preparing multi-metal ozone catalyst by blending-impregnation combined method

Info

Publication number: CN114602494B
Application number: CN202210511861.0A
Authority: CN
Inventors: 吴昌永; 付丽亚; 王盼新
Original assignee: Chinese Research Academy of Environmental Sciences
Current assignee: Chinese Research Academy of Environmental Sciences
Priority date: 2022-05-12
Filing date: 2022-05-12
Publication date: 2022-07-29
Anticipated expiration: 2042-05-12
Also published as: CN114602494A

Abstract

A method for preparing a multi-metal ozone catalyst by a blending-impregnation combined method belongs to the technical field of catalyst preparation. The method comprises the following steps: s1, fully mixing the aluminum oxide powder and the metal oxide powder; s2, uniformly mixing, putting into a round pot granulator, and adding an adhesive into the round pot granulator; s3, after granulation is finished, drying in a forced air drying box; s4, preparing a plurality of steeping liquids containing different active metal salts; s5, dipping step by step; the invention adopts solid powder to fully mix in the mixing stage, increases the mixing uniformity of the alumina carrier and the metal oxide powder, adopts a step-by-step impregnation mode in the impregnation stage, can well improve the problem of competitive adsorption among active metal components, and can prepare a catalyst product with concentrated surface layer distribution and low inner layer concentration according to the diffusion condition of a metal salt solution in a catalyst precursor.

Description

Method for preparing multi-metal ozone catalyst by blending-impregnation combined method

Technical Field

The invention belongs to the technical field of catalyst preparation, and particularly relates to a method for preparing a multi-metal ozone catalyst by a blending-impregnation combined method.

Background

Aluminum oxide (Al) ₂ O ₃ ) The catalyst is a commonly used catalyst, adsorbent and the like, but when the alumina is used as the catalyst to catalyze the ozone oxidation organic matter, the reaction rate is slow, the efficiency is low, and the effect of removing complex macromolecular organic matter which is difficult to degrade is almost not achieved. Therefore, when alumina is used as a catalyst in industry, a metal active component is generally loaded on the surface of the alumina to improve the catalytic performance of the alumina.

The preparation method of the load type alumina catalyst is various, and the preparation method of the alumina catalyst in the industry at present adopts two methods of an impregnation method and a blending method, wherein the impregnation method is to put a carrier into liquid or gas containing active substances for impregnation, filter the residual liquid after the adsorption reaches a balance, and then dry, roast and the like to prepare the catalyst.

The active metal components in the catalyst obtained by the blending method are uniformly distributed, and the distribution condition of the active metal components in the catalyst carrier can be controlled by the impregnation method according to the different diffusion speeds of the active metal components in the catalyst precursor. Therefore, the method of mixing and dipping first is used for preparing the catalyst with one or more metal active components uniformly distributed and one or more metal active components non-uniformly distributed so as to ensure the catalytic efficiency and stability of the catalyst.

Disclosure of Invention

Aiming at the problems, the invention provides a method for preparing a multi-metal ozone catalyst by a blending-impregnation combined method, wherein the catalyst has the characteristics of high activity, high stability and non-uniform distribution of metal active components.

The technical scheme of the invention is as follows: a method for preparing a multi-metal ozone catalyst by a blending-impregnation combined method comprises the following steps:

s1, washing the surface of the alumina oxide with deionized water, placing the alumina oxide in an oven for drying, mixing alumina powder and metal oxide powder according to the mass ratio of 7:1-2, adding 0.02-0.3wt% of adhesive, and mixing uniformly to obtain a premix, wherein the particle size range of the alumina powder is 200-600 meshes, the purity of the metal oxide powder is 95-99.99%, and solid powder is adopted for fully mixing in the mixing stage, so that all active components in the final catalyst product are uniformly distributed from inside to outside;

s2, placing the premix in a round pot granulator, adjusting the rotating speed and the elevation angle of a turntable of the round pot granulator to enable the adhesive, the alumina powder and the metal oxide powder to be agglomerated through adsorption and bonding to obtain premix particles, and performing rolling granulation by using the round pot granulator without extrusion, kneading and other processes;

s3, after granulation is finished, placing the premix particles in a forced air drying oven, drying for 4-6h at the temperature of 80-110 ℃, and obtaining a catalyst precursor after drying is finished;

s4, mixing deionized water with manganese nitrate, copper nitrate, zinc nitrate and magnesium nitrate respectively to prepare five kinds of impregnation liquid correspondingly, wherein the concentrations of corresponding metal salts in the five kinds of impregnation liquid are respectively as follows: manganese nitrate: 0.01-2.5mol/L, copper nitrate: 0.01-3.5mol/L, zinc nitrate: 0.01-3.0mol/L, magnesium nitrate: 0.01-2.5 mol/L;

s5, sequentially and fully mixing the catalyst precursor with the five impregnation liquids, wherein the catalyst precursor and each impregnation liquid are mixed, then the catalyst precursor and each impregnation liquid are cleaned, dried and roasted, and after the catalyst precursor and all the impregnation liquids are mixed, the catalyst precursor is naturally cooled to room temperature to obtain a catalyst product, wherein the mixing ratio of the catalyst precursor to the impregnation liquids is as follows: 100 g of catalyst precursor is added into 100-150mL of impregnation liquid, the particle size of the obtained catalyst product is 0.5-6mm, and the distribution condition of the active metal components can be determined according to different water qualities, so that the catalyst product meeting the specific requirements can be correspondingly prepared.

As a modification, in the step S1, the grain size of the alumina powder is in the range of 200-600 mesh, and the metal oxide powder is selected from any one of manganese oxide powder, copper oxide powder and cerium oxide powder with the grain size of 100-500 mesh.

As a modification, in step S1, the adhesive is selected from any one of acetic acid, sesbania powder, trichloroacetic acid, and konjac glucomannan.

As an improvement scheme, in the step S1, after the surface of the alumina carrier is washed with deionized water, the alumina carrier is placed in a closed container and subjected to microwave treatment for 5-6 hours to increase the pore diameter of the surface of the alumina carrier, wherein the microwave frequency is 2000-2200MHz, and the pore structure of the surface of the alumina carrier can be optimized through the microwave treatment to increase the loading and improve the catalytic performance of the catalyst.

As an improved scheme, in the step S2, when the rotation speed of the circular pan granulator is adjusted, the mixture is stirred at a speed of 20 to 40r/min for 35 to 45min, so that the adhesive and the solid powder are agglomerated to form particles with smaller particle size through adsorption and bonding; and then, increasing the rotation speed to 40-50r/min, and continuously stirring for 1-2h so as to facilitate the adhesion of the small particles formed in the early stage to the solid powder to form particles with larger particle size, wherein the elevation angle of a turntable of the circular pan granulator is 30-75 degrees.

As a modified scheme, in step S5, the catalyst product is packaged by using a paper-plastic woven bag or a wooden barrel.

As an improvement scheme, in step S1, alumina powder and metal oxide powder are mixed in a mixing and screening device, the mixing and screening device includes a screening main body with a feeding port and a discharging port at upper and lower ends thereof, a mixing and adding main body connected to the discharging port, a screening mesh plate disposed in the screening main body, and an adhesive dispersing and adding cylinder disposed in the adding main body, the adhesive dispersing and adding cylinder includes a main flow pipe with an adding port and a plurality of spraying nozzles on an outer wall thereof, and a plurality of liquid separation anti-blocking covers disposed on an outer wall of the main flow pipe along a circumferential direction and having a plurality of liquid guiding vertical grooves on an inner wall thereof, a plurality of stirring rods uniformly distributed are disposed on a sidewall of the liquid separation anti-blocking covers, a bottom end of the main flow pipe is driven to rotate by a motor, and a height of the main flow pipe is adjustable, when the alumina powder and the metal oxide powder are required to be mixed, the alumina powder and the metal oxide powder are simultaneously added into the screening main body through the feeding port, filter it through the otter board that sieves, make the aluminium oxide powder and the metal oxide powder after the initial mixing that satisfy the particle size requirement, fall to mixing in the interpolation main part through the otter board, and simultaneously, add the gluing agent to the mainstream through the interpolation mouth in, rotate through motor drive mainstream through-tube, at this moment, the gluing agent is from each jet nozzle blowout, through drawing liquid vertical retort dispersion flow to mix powder everywhere, and stir through the puddler, obtain misce bene's premix, through the process, the mixing degree of consistency between multiplicable each raw materials, the catalyst performance who makes the preparation is good, and the requirement is satisfied.

As an improvement scheme, the otter board of sieving has a plurality ofly, and a plurality of otter boards of sieving end to end connect gradually and the slope sets up in the screening main part, and screening main part outer wall just corresponds every otter board downward sloping department of sieving and is equipped with the mouth that scatters, and screening main part outer wall is equipped with and can just inside be equipped with the crushing case of crushing roller with scattering mouthful cladding wherein, crushing bottom of the case end and pan feeding mouth intercommunication, through sieving the back many times, unsatisfied requirement alumina powder and metallic oxide powder fall into the crushing incasement to utilize the crushing roller to carry out the breakage back, fall into the screening main part through the pan feeding mouth again, repeated sieving increases the utilization ratio of alumina powder and metallic oxide powder, avoids the wasting of resources.

As an improvement scheme, the bottom end of the main flow pipe is provided with an L-shaped blocking partition plate, and the injection nozzle can be blocked in the liquid-separating anti-blocking cover through the design of the L-shaped blocking partition plate, so that the injection nozzle is prevented from being blocked.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, solid powder is fully mixed in a mixing stage, the mixing uniformity of an alumina carrier and metal oxide powder is increased, a step-by-step impregnation mode is adopted in an impregnation stage, the problem of competitive adsorption among active metal components can be well improved, meanwhile, a catalyst product with concentrated surface layer distribution and low inner layer concentration can be prepared according to the diffusion condition of a metal salt solution in a catalyst precursor, and when a round pot granulator is adopted for rolling granulation, the processes of extrusion, kneading and the like do not exist, meanwhile, an adhesive and the like are added, and the catalyst obtained after roasting has a large specific surface area and has the characteristics of high activity, high stability and non-uniform distribution of metal active components;

(2) when the catalyst prepared by the invention is used for treating actual industrial wastewater by ozone catalytic oxidation, the removal efficiency of organic pollutants in the wastewater can reach 40-60%, the catalyst can be applied to the field of ozone catalytic oxidation of industrial wastewater, and the catalyst has good catalytic effect and high stability.

Drawings

FIG. 1 is a diagram showing the effect of the present invention in preparing a bimetallic ozone catalyst for catalyzing ozone to oxidize secondary effluent of petrochemical wastewater by stepwise impregnation;

FIG. 2 is a schematic view of the internal structure of the mixing and screening device of the present invention;

fig. 3 is an enlarged view of the invention at a in fig. 2.

The device comprises a main screening body, a main feeding port, a main discharging port, a main scattering port, a main crushing box, a main crushing roller, a main mixing and adding body, a main sieving screen plate, a main mixing and adding cylinder, a main circulating pipe, a main adding port, a main separating and buckling preventing cover, a main separating and buckling groove 410, a vertical liquid guiding groove 411-L-shaped blocking partition plate and a stirring rod 412.

Detailed Description

In order to further understand the contents of the present invention, the present invention is described in detail by examples below.

Example 1

A method for preparing a multi-metal ozone catalyst by a blending-impregnation combined method comprises the following steps:

s1, washing the surface of the alumina carrier by deionized water, placing the alumina carrier in an oven for drying, mixing the alumina powder and the manganese oxide powder according to the mass ratio of 7:1, adding 0.02wt% of acetic acid, and uniformly mixing to obtain a premix, wherein the particle size range of the alumina powder is 200-300 meshes, and the purity of the manganese oxide powder is 95%;

s2, placing the premix in a round pot granulator, and adjusting the rotating speed and the elevation angle of a turntable of the round pot granulator to enable acetic acid, alumina powder and manganese oxide powder to be agglomerated through adsorption and bonding to obtain premix particles, wherein when the rotating speed of the round pot granulator is adjusted, stirring is performed for 35min at the speed of 20 r/min; then, the rotating speed is increased to 40r/min, stirring is continuously carried out for 1h, and the elevation angle of a rotary table of the circular pan granulator is 30 degrees;

s3, after granulation is finished, placing the premix particles in a forced air drying oven, drying for 4 hours at the temperature of 80 ℃, and obtaining a catalyst precursor after drying is finished;

s4, mixing deionized water with manganese nitrate, copper nitrate, zinc nitrate and magnesium nitrate respectively to prepare five kinds of impregnation liquid correspondingly, wherein the concentrations of corresponding metal salts in the five kinds of impregnation liquid are respectively as follows: manganese nitrate: 0.01mol/L, copper nitrate: 0.01mol/L, zinc nitrate: 0.01mol/L, magnesium nitrate: 0.01 mol/L;

s5, mixing the catalyst precursor with the five impregnation liquids respectively, cleaning, drying and roasting the catalyst precursor after mixing with each impregnation liquid, naturally cooling to room temperature after mixing the catalyst precursor with all the impregnation liquids to obtain a catalyst product, and then packaging the catalyst product by adopting a paper-plastic woven bag, wherein the mixing ratio of the catalyst precursor to the impregnation liquids is as follows: 100 g of catalyst precursor is added into 100mL of impregnation liquid, and the particle size of the obtained catalyst product is 0.5 mm.

Example 2

s1, washing the surface of the alumina carrier by deionized water, placing the alumina carrier in an oven for drying, then mixing the alumina powder and the copper oxide powder according to the mass ratio of 7:1.5, adding 0.15wt% of sesbania powder, and uniformly mixing to obtain a premix, wherein the particle size range of the alumina powder is 300-400 meshes, and the purity of the copper oxide powder is 98%;

s2, placing the premix in a round pot granulator, and adjusting the rotating speed and the elevation angle of a turntable of the round pot granulator to enable sesbania powder, alumina powder and manganese oxide powder to be agglomerated through adsorption and bonding to obtain premix particles, wherein when the rotating speed of the round pot granulator is adjusted, stirring is carried out for 40min at the speed of 30 r/min; then, the rotating speed is increased to 45r/min, stirring is continuously carried out for 1.5 hours, and the elevation angle of a rotary table of the circular pan granulator is 55 degrees;

s3, after granulation is finished, placing the premix particles in a forced air drying oven, drying for 5 hours at the temperature of 90 ℃, and obtaining a catalyst precursor after drying is finished;

s4, mixing deionized water with manganese nitrate, copper nitrate, zinc nitrate and magnesium nitrate respectively to prepare five kinds of impregnation liquid correspondingly, wherein the concentrations of corresponding metal salts in the five kinds of impregnation liquid are respectively as follows: manganese nitrate: 1.2mol/L, copper nitrate: 2.1mol/L, zinc nitrate: 1.6mol/L, magnesium nitrate: 1.3 mol/L;

s5, mixing the catalyst precursor with the five impregnation liquids respectively, cleaning, drying and roasting the catalyst precursor after mixing with each impregnation liquid, naturally cooling to room temperature after mixing the catalyst precursor with all the impregnation liquids to obtain a catalyst product, and then packaging the catalyst product by adopting a paper-plastic woven bag, wherein the mixing ratio of the catalyst precursor to the impregnation liquids is as follows: 130mL of impregnating solution is added with 100 g of catalyst precursor, and the particle size of the obtained catalyst product is 3 mm.

Example 3

s1, washing the surface of the alumina carrier by deionized water, placing the alumina carrier in an oven for drying, then mixing alumina powder and cerium oxide powder according to the mass ratio of 7:2, adding 0.3wt% of trichloroacetic acid into the mixture, and uniformly mixing to obtain a premix, wherein the particle size range of the alumina powder is 400-600 meshes, and the purity of the cerium oxide powder is 99.99%;

s2, placing the premix in a round pot granulator, and adjusting the rotating speed and the elevation angle of a turntable of the round pot granulator to enable trichloroacetic acid, alumina powder and manganese oxide powder to be agglomerated through adsorption and bonding to obtain premix particles, wherein when the rotating speed of the round pot granulator is adjusted, the premix particles are stirred at the speed of 40r/min for 45 min; then, the rotating speed is increased to 50r/min, stirring is continuously carried out for 2 hours, and the elevation angle of a rotary table of the circular pan granulator is 75 degrees;

s3, after granulation is finished, placing the premix particles in a forced air drying oven, drying for 6 hours at the temperature of 110 ℃, and obtaining a catalyst precursor after drying is finished;

s4, mixing deionized water with manganese nitrate, copper nitrate, zinc nitrate and magnesium nitrate respectively to prepare five kinds of impregnation liquid correspondingly, wherein the concentrations of corresponding metal salts in the five kinds of impregnation liquid are respectively as follows: manganese nitrate: 2.5mol/L, copper nitrate: 3.5mol/L, zinc nitrate: 3.0mol/L, magnesium nitrate: 2.5 mol/L;

s5, mixing the catalyst precursor with the five impregnation liquids respectively, cleaning, drying and roasting the catalyst precursor after mixing with each impregnation liquid, naturally cooling to room temperature after mixing the catalyst precursor with all the impregnation liquids to obtain a catalyst product, and then packaging the catalyst product by adopting a paper-plastic woven bag, wherein the mixing ratio of the catalyst precursor to the impregnation liquids is as follows: 100 g of catalyst precursor is added into 150mL of impregnation liquid, and the particle size of the obtained catalyst product is 6 mm.

Example 4

This example describes the structure of the mixing and screening apparatus used in examples 1-3 above:

as shown in fig. 2 and 3, in step S1, alumina powder and metal oxide powder are mixed in a mixing and screening device, the mixing and screening device includes a screening main body 1 having a feeding port 10 and a discharging port 11 at upper and lower ends thereof, a mixing and adding main body 2 connected to the discharging port 11, a screening mesh plate 3 disposed in the screening main body 1, and an adhesive dispersing and adding barrel 4 disposed in the adding main body 2, the adhesive dispersing and adding barrel 4 includes a main runner pipe 40 having an adding

port

400 and 15 spraying nozzles 401 on an outer wall thereof, 4 liquid separation anti-blocking covers 41 circumferentially disposed on an outer wall of the main runner pipe 40 and having 8 liquid guiding vertical grooves 410 on an inner wall thereof, an L-shaped blocking baffle 411 is disposed at a bottom end of the main runner pipe 40, 8 stirring rods 412 uniformly distributed on a side wall of the liquid separation anti-blocking cover 41, the bottom end of the main runner pipe 40 is driven to rotate by a motor, and the main runner pipe 40 has an adjustable height, the height of the main circulation pipe 40 can be adjusted according to the adding amount of the alumina powder and the metal oxide powder at the bottom end of the mixing and adding main body 2, so that the stirring rod 412 can stir; when the aluminum oxide powder and the metal oxide powder are required to be mixed, the aluminum oxide powder and the metal oxide powder are simultaneously added into the screening main body 1 through the feeding port 10, the aluminum oxide powder and the metal oxide powder which meet the particle size requirement are primarily mixed by filtering the screening net plate 3 and then fall into the mixed adding main body 2 through the screening net plate 3, meanwhile, the adhesive is added into the main circulating pipe 40 through the adding port 400, the main circulating pipe 40 is driven to rotate through the motor, at the moment, the adhesive is sprayed out from each spraying nozzle 401, is dispersed and flows to each part of the mixed powder through the liquid guiding vertical groove 410, is stirred through the stirring rod 412, and the uniformly mixed premix is obtained, through the process, the mixing uniformity among the raw materials can be increased, the prepared catalyst has excellent performance and meets the requirement, and through the design of the L-shaped blocking baffle plate 411, the spray nozzle 401 can be blocked in the liquid separation anti-blocking cover 41, so that the spray nozzle 401 is prevented from being blocked;

sieve otter board 3 and have 4, 4 sieve otter board 3 end to end connect gradually and the slope sets up in screening main part 1, screening main part 1 outer wall and correspond every 3 downward sloping departments of otter board that sieve are equipped with the mouth 12 that scatters, screening main part 1 outer wall is equipped with can be with scattering the mouth 12 cladding wherein and the inside crushing case 13 that is equipped with crushing

roller

130, 13 bottom of crushing case and pan feeding mouth 10 intercommunication, through sieving many times the back, unsatisfied required aluminium oxide powder falls into crushing case 13 with the metallic oxide powder, and utilize crushing roller 130 to carry out the breakage back, fall into screening main part 1 through pan feeding mouth 10 again through current device, repeat the sieving, increase the utilization ratio of aluminium oxide powder and metallic oxide powder, avoid the wasting of resources.

Example 5

The present embodiment is different from embodiment 3 in that:

in step S1, the surface of the alumina carrier is washed by deionized water and then placed in a closed container for microwave treatment for 5 hours to increase the aperture of the surface of the alumina carrier, wherein the microwave frequency is 2000 MHz.

Example 6

The present embodiment is different from embodiment 5 in that:

in step S1, the surface of the alumina carrier is washed by deionized water and then placed in a closed container for microwave treatment for 6 hours to increase the aperture of the surface of the alumina carrier, wherein the microwave frequency is 2200 MHz.

Test example 1

The same industrial wastewater was treated using the supported alumina catalyst for industrial wastewater treatment in the prior art and the catalysts prepared by the methods of examples 1, 2, 3, 5, and 6 to obtain the performance index parameters of the treated water body, which are specifically shown in table 1:

table 1: performance index parameters of water body after industrial wastewater treatment by using catalyst in the prior art and catalysts in examples 1, 2, 3, 5 and 6

As can be seen from table 1, when the same industrial wastewater is treated by using the catalysts of the prior art and examples 1, 2, 3, 5, and 6, the methods of examples 1, 2, 3, 5, and 6 have higher removal rates for COD, TOC, SS, TN, and ammonia nitrogen, which indicates that the catalytic effect of the catalyst prepared in the examples of the present invention is better than that of the prior art.

As can be seen from comparative examples 1 to 3, the parameters related to example 3 are most effective in treating industrial wastewater during the treatment of petrochemical wastewater, and thus, the scheme of example 3 is superior to examples 1 and 2.

Comparing example 5 with example 6, it can be seen that the parameters related to example 6 are the best for treating industrial wastewater during the treatment of industrial wastewater, therefore, the scheme of example 6 is better than that of example 5, and it can be seen that example 6 is the best example.

Claims

1. A method for preparing a multi-metal ozone catalyst by a blending-impregnation combined method is characterized by comprising the following steps:

s1, washing the surface of the alumina oxide with deionized water, placing the alumina oxide in an oven for drying, mixing alumina powder and metal oxide powder according to the mass ratio of 7:1-2, adding 0.02-0.3wt% of adhesive, and uniformly mixing to obtain a premix, wherein the particle size range of the alumina powder is 200-600 meshes, and the purity of the metal oxide powder is 95-99.99%;

s2, placing the premix in a round pot granulator, and adjusting the rotating speed and the elevation angle of a turntable of the round pot granulator to enable the adhesive, the alumina powder and the metal oxide powder to be agglomerated through adsorption and bonding to obtain premix particles;

s4, mixing the deionized water with manganese nitrate, copper nitrate, zinc nitrate and magnesium nitrate respectively to prepare four impregnation liquids correspondingly, wherein the concentrations of the corresponding metal salts in the four impregnation liquids are respectively as follows: manganese nitrate: 0.01-2.5mol/L, copper nitrate: 0.01-3.5mol/L, zinc nitrate: 0.01-3.0mol/L, magnesium nitrate: 0.01-2.5 mol/L;

s5, sequentially and fully mixing the catalyst precursor with the four impregnation liquids, wherein the catalyst precursor and each impregnation liquid are mixed, and then the catalyst precursor and each impregnation liquid are cleaned, dried and roasted, and when the catalyst precursor and all the impregnation liquids are mixed, the catalyst precursor and all the impregnation liquids are naturally cooled to room temperature to obtain a catalyst product, wherein the mixing ratio of the catalyst precursor to the impregnation liquids is as follows: 100 g of catalyst precursor is added into 150mL of 100-150mL of impregnation liquid, and the particle size of the obtained catalyst product is 0.5-6 mm;

in step S1, the grain size of the alumina powder is 200-600 mesh, and the metal oxide powder is selected from any one of manganese oxide powder, copper oxide powder and cerium oxide powder with grain size of 100-500 mesh;

in the step S1, aluminum oxide powder and metal oxide powder are mixed in a mixing and screening device, the mixing and screening device comprises a screening main body (1) with an upper end and a lower end respectively provided with a feeding port (10) and a discharging port (11), a mixing and adding main body (2) connected with the discharging port (11), a screening screen plate (3) arranged in the screening main body (1), and an adhesive dispersing and adding cylinder (4) arranged in the adding main body (2), wherein the adhesive dispersing and adding cylinder (4) comprises a main flow pipe (40) with an adding port (400) and a plurality of spraying nozzles (401) arranged on the outer wall, a plurality of liquid separation anti-blocking covers (41) arranged on the outer wall of the main flow pipe (40) along the circumferential direction and provided with a plurality of liquid guiding vertical grooves (410) on the inner wall, a plurality of stirring rods (412) uniformly distributed are arranged on the side wall of the anti-blocking covers (41), and the bottom end of the main flow pipe (40) is driven to rotate by a motor, and the height of the main flow pipe (40) is adjustable;

the screening machine is characterized in that a plurality of screening net plates (3) are arranged, the screening net plates (3) are sequentially connected end to end and are obliquely arranged in the screening main body (1), a scattering port (12) is formed in the outer wall of the screening main body (1) and corresponds to the downward inclination position of each screening net plate (3), a crushing box (13) capable of coating the scattering port (12) and provided with a crushing roller (130) inside is arranged on the outer wall of the screening main body (1), and the bottom end of the crushing box (13) is communicated with the feeding port (10);

the bottom end of the main circulation pipe (40) is provided with an L-shaped blocking partition plate (411).

2. The method for preparing the multi-metal ozone catalyst by the co-mingling-impregnation combined method according to claim 1, wherein in the step S1, the adhesive is any one selected from acetic acid, sesbania powder, trichloroacetic acid and konjac glucomannan.

3. The method for preparing the multi-metal ozone catalyst by the combined blending-impregnation method as claimed in claim 1, wherein in step S1, the alumina carrier surface is washed with deionized water and then placed in a closed container for microwave treatment for 5-6h to increase the pore diameter of the alumina carrier surface, wherein the microwave frequency is 2000-2200 MHz.

4. The method for preparing the multi-metal ozone catalyst by the combined blending-impregnation method as claimed in claim 1, wherein in the step S2, when the rotation speed of the circular kettle granulator is adjusted, the stirring is performed at a speed of 20-40r/min for 35-45 min; then, the rotating speed is increased to 40-50r/min, the stirring is continued for 1-2h, and the elevation angle of the rotary table of the circular pan granulator is 30-75 degrees.

5. The method for preparing the multi-metal ozone catalyst by the combined co-mingling-impregnation method according to claim 1, wherein in the step S5, the catalyst product is packaged by a paper-plastic woven bag or a wooden barrel.