Warm cloud catalyst with high hygroscopicity and low corrosivity and preparation method thereof

Abstract

The invention relates to a warm cloud catalyst with high hygroscopicity and low corrosivity and a preparation method thereof, and belongs to the technical field of artificial weather catalysts. The catalyst comprises the following raw materials in percentage by mass: 5%-70% of inorganic sodium salt, 0%-15% of inorganic calcium salt, 5%-30% of inorganic magnesium salt, 2%-30% of inorganic potassium salt, 2%-20% of inorganic lithium salt, 5%-35% of weak acid and strong alkali salt and 0.1%-5% of an additive. According to the catalyst, sodium salt, lithium salt and magnesium salt are compounded, so that efficient moisture absorption in a full-humidity range is realized; a passive film-ion complexing dual anti-corrosion mechanism is constructed through weak acid and strong alkali salt; the moisture absorption rate and cost are balanced by compounding the inorganic salt, a hydrophobic membrane is formed on the surface of the catalyst through the additive, caking in a normal-humidity environment is low, and the fluidity and environmental suitability are improved. According to the method, the particle size of the catalyst is accurately regulated and controlled through air jet pulverization and the laser particle size analyzer, the method is suitable for multiple types of warm clouds, the cost is reduced, and the large-scale application requirement can be met.

Description

Technical Field

[0001] This invention relates to a warm cloud catalyst with high hygroscopicity and low corrosivity and its preparation method, belonging to the field of weather modification catalyst technology. Background Technology

[0002] Depending on the temperature of the target cloud, weather modification catalysts can be divided into cold cloud catalysts and warm cloud catalysts. Silver iodide catalysts, as cold cloud catalysts, have achieved global consensus and are widely used, with their dispersal technology and operational systems becoming increasingly sophisticated. Warm clouds are less likely to form precipitation because their cloud physical structure is stable, water droplets under natural conditions are uniform in size, and they lack the large water droplets needed to trigger gravitational collisions and coalescence. This makes it difficult to disrupt the colloidal stability within the cloud and for precipitation to form through diffusion, condensation, and collision-coalescence. Therefore, the key to warm cloud catalysis is to introduce hygroscopic nuclei through the catalyst, rapidly absorbing moisture to form large water droplets, creating an environment where large and small water droplets coexist, and promoting the collision-coalescence process.

[0003] Currently, warm cloud catalysis in my country mainly employs flame-based catalyst combustion seeding. The catalyst is delivered to the cloud base via carriers such as aircraft, flares, and rockets. The hygroscopic nuclei generated during combustion, with a diameter of 0.1 μm to 10 μm, enter the cloud with updrafts, absorbing moisture and growing into larger water droplets to alter the cloud droplet distribution. However, existing technologies suffer from the following core drawbacks: 1) Poor particle size adaptability: The particle size of combustion products of existing flame-type catalysts is mostly concentrated in 0.05 μm ~ 2 μm. For example, Chinese patent CN102161605B, "A hygroscopic catalyst and its preparation method", discloses a catalyst with an average particle size of 0.3 μm ~ 0.8 μm. The small particle size leads to a long hygroscopic growth cycle, which may cause the effective rain enhancement window in the cloud to be missed. On the other hand, non-combustion catalysts, such as Chinese patent CN104322334B, "A warm cloud catalyst, preparation method and its application", disclose plant ash / carbon powder with a particle size of 0.5 μm ~ 120 μm. The large particle size range means that particles with a particle size greater than 50 μm settle too quickly, resulting in insufficient effective utilization and making it impossible to adapt to the cloud droplet spectrum requirements of different warm cloud types (such as cumulus and stratus). 2) Insufficient moisture absorption efficiency: Traditional hygroscopic salts (such as sodium chloride) have a fast moisture absorption rate, but their moisture absorption activity decreases significantly in warm cloud environments with a relative humidity (RH) of less than 75%. For example, sodium chloride absorbs less than 0.1 g / g of moisture when the RH is less than 60%. In contrast, new materials such as metal-organic frameworks (MOFs) and amorphous silica (SiO2) have lower moisture absorption efficiency. While substances like nH2O improve moisture absorption performance in low-humidity environments, their cost is 20 to 50 times higher than that of traditional hygroscopic salts, and their rapid water release rate makes it difficult to sustain the growth of water droplets. 3) High equipment corrosivity: Traditional hygroscopic salts (such as sodium chloride) easily form high-concentration ionic solutions upon dissolution, resulting in corrosion rates of 0.10 mm / year to 0.15 mm / year on dispersing equipment (such as aircraft engine pipes and rocket launcher metal components), far exceeding the permissible corrosion standard requirement of 0.05 mm / year for industrial equipment. Existing improvement solutions, such as Chinese patent application CN120079427A, "A novel composite anti-fogging catalyst formulation and its preparation method," reduce corrosivity through a composite carrier, but only reduce ion concentration through physical dilution, failing to inhibit corrosion reactions at the chemical level. Long-term use still leads to a shortened equipment lifespan. 4) Storage and dissemination defects: Traditional salt catalysts are prone to moisture absorption and agglomeration. For example, NaCl agglomerates by 50% in an environment with RH greater than 60% for 72 hours, which leads to uneven dispersion during dissemination. Combustion-type catalysts, such as the Chinese patent application "A method for preparing a combustion-type warm cloud catalyst" with publication number CN120289259A, solve the storage problem, but require a complex casting and solidification process. In addition, the combustion products contain trace amounts of harmful gases, such as nitrogen oxides (NOx), which are not suitable for sensitive areas near the ground, such as farmland and urban airspace.

[0004] Warm cloud precipitation accounts for over 50% of total precipitation in my country. In summer, warm cloud thickness ranges from 3 km to 5 km in the north and can reach 5 km to 6 km in the south, indicating significant potential for increased precipitation. However, currently, the amount of warm cloud catalysts used in operations is only one-tenth that of cold cloud catalysts, leading to widespread mismatches between warm cloud and silver iodide-based cold cloud catalysts. Therefore, developing warm cloud catalysts that combine high hygroscopicity, low corrosion, controllable particle size, and low cost is crucial to overcoming the operational bottlenecks of warm cloud rain enhancement. Summary of the Invention

[0005] To overcome the shortcomings of existing warm cloud catalysts, such as low moisture absorption efficiency, strong equipment corrosion, poor particle size adaptability, and easy moisture absorption and agglomeration, this invention provides a warm cloud catalyst with high moisture absorption and low corrosion and its preparation method. Through innovative component design and process optimization, it achieves synergistic performance of "rapid moisture absorption - low corrosion protection - precise particle size control".

[0006] The objective of this invention is achieved through the following technical solution: A warm cloud catalyst with high hygroscopicity and low corrosivity, wherein the components and their mass fractions are as follows, based on the total mass of the catalyst raw materials (100%): Inorganic sodium salts 5% ~ 70%, Inorganic calcium salts 0% ~ 15%, Inorganic magnesium salts 5% ~ 30%, Inorganic potassium salts 2% ~ 30%, Inorganic lithium salts 2% ~ 20%, 5% ~ 35% of weak acid-strong base salts Additives 0.1% ~ 5%, All components are powders.

[0007] Furthermore, a warm cloud catalyst with high hygroscopicity and low corrosivity is preferred. Based on the total mass of the catalyst raw material (100%), the components and their mass fractions are as follows: Inorganic sodium salts 25% ~ 70%, Inorganic calcium salts 0% ~ 8%, Inorganic magnesium salts 5% ~ 30%, Inorganic potassium salts 2% ~ 16%, Inorganic lithium salts 2% ~ 20%, 5% ~ 20% of weak acid-strong base salts Additives 0.1% ~ 5%, The inorganic sodium salt is at least one of sodium chloride, sodium bromide, and sodium sulfate; preferably sodium chloride and sodium sulfate.

[0008] Inorganic calcium salts are at least one of calcium chloride and calcium sulfate.

[0009] The inorganic magnesium salt is at least one of magnesium chloride and magnesium sulfate.

[0010] The inorganic potassium salt is at least one of potassium chloride and potassium sulfate.

[0011] The inorganic lithium salt is at least one of lithium chloride and lithium sulfate.

[0012] The weak acid-strong base salt is at least one of sodium acetate, potassium acetate, calcium acetate, magnesium acetate, sodium phosphate, sodium borate, sodium metasilicate, sodium silicate, sodium carbonate, magnesium carbonate, potassium carbonate, and lithium carbonate; preferably at least one of sodium acetate, sodium borate, sodium metasilicate, and sodium carbonate.

[0013] The additive is at least one of magnesium stearate, ferric ammonium citrate, calcium silicate, potassium ferrocyanide, silicon dioxide, and tricalcium phosphate; preferably at least one of magnesium stearate, ferric ammonium citrate, calcium silicate, potassium ferrocyanide, and silicon dioxide.

[0014] A method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity according to the present invention, the method comprising the following steps: (1) Raw material pretreatment: Dry the inorganic salt and weak acid strong base salt to remove free water; then pass them through a 20-100 mesh copper sieve, take the sieve residue, remove excessively large particles to avoid uneven crushing in the later stage, and obtain the pretreated salt. Wherein, the inorganic salt is a combination of inorganic sodium salt, inorganic calcium salt, inorganic magnesium salt, inorganic potassium salt and inorganic lithium salt with a mass fraction not of 0%; (2) Premixing: Weigh the pretreated salt from step (1) according to the formula ratio, add it to the mixer and stir evenly; pass it through a 20-mesh copper sieve to remove impurities twice, and take the residue to obtain mixture A; (3) Additive mixing and drying: Add the additive to the mixture A obtained in step (2), continue to stir evenly in the mixer, pass through a 20-60 mesh copper sieve, take the residue, dry, pass through a 20-80 mesh copper sieve again, take the residue, and obtain mixture B; (4) Airflow pulverization and particle size control: The mixture B obtained in step (3) is fed into an airflow pulverizer. The target particle size is precisely controlled by adjusting the pulverization pressure and the speed of the classifier wheel. After pulverization, a dry powder product is obtained, which is the warm cloud catalyst with high hygroscopicity and low corrosivity described in this invention.

[0015] Furthermore, in step (1): Preferably, use a copper sieve with a mesh size of 40-80. The preferred drying method is to dry in an oven at 70℃~100℃ for 6h~24h; In step (2): It is preferable to stir at a speed of 50 r / min to 70 r / min for 15 min to 30 min; In step (3): Additives are preferably added to the mixture A obtained in step (2), and the mixture is stirred evenly in a mixer. The mixture is then passed through a 40-60 mesh copper sieve, the residue is collected, dried, and then passed through a 40-mesh copper sieve again to collect the residue, thus obtaining mixture B. It is preferable to continue stirring at the same speed as in step (2) for 8 min to 10 min; The preferred drying method is to dry in an oven at 60℃~70℃ for 6h~10h; In step (4): The preferred crushing pressure is 0.9 MPa ~ 1.2 MPa, and the classifying wheel speed is 3000 r / min ~ 5000 r / min.

[0016] The catalyst described in this invention is a dry powder product, and the following packaging and storage methods can be selected according to the application method: 1) Vacuum packaging in aluminum-plastic composite bags, with a vacuum degree of less than or equal to -0.09MPa; 2) The protective gas is bottled, and the purity of the protective gas is greater than or equal to 99.9%, with nitrogen being the preferred protective gas; 3) It is mixed with the flame carrier for use as a combustion catalyst and stored in a sealed, moisture-proof container throughout the process.

[0017] Beneficial effects (1) The present invention provides a warm cloud catalyst with high hygroscopicity and low corrosivity. The catalyst is compounded by sodium salt + lithium salt + magnesium salt to achieve efficient moisture absorption in the full humidity range: under high altitude warm cloud conditions with RH 30% ~ 50%, the moisture absorption is greater than or equal to 0.2 g / g; under plain warm cloud conditions with RH 50% ~ 70%, the moisture absorption is greater than or equal to 0.5 g / g; under coastal warm cloud conditions with RH above 70%, the moisture absorption is greater than or equal to 1.0 g / g, which can match the effective rain enhancement window in the cloud; (2) This invention provides a warm cloud catalyst with high hygroscopicity and low corrosivity. The catalyst constructs a dual anti-corrosion mechanism of "passivation film-ion complexation" through a weak acid-strong base salt: 1) It dissolves in water to form a weak alkaline pH of 8.0-9.5, which reacts with ferric ions (Fe3+) on the metal surface. 3+ 1) Reacts to form a Fe(OH)3 passivation film; 2) Reacts with chloride ions (Cl... - Forming stable complexes reduces the conductivity of the solution, thus inhibiting electrochemical corrosion at its source, such as sodium metasilicate; (3) This invention provides a warm cloud catalyst with high hygroscopicity and low corrosivity. Compared with traditional hygroscopic salt NaCl, the catalyst balances the hygroscopic rate and cost by compounding inorganic salts, avoiding the problem of low humidity hygroscopic failure of single salts. Inorganic sodium salt provides basic hygroscopic activity, and sodium bromide has a hygroscopic rate that is 40% higher than that of sodium chloride, making it suitable for warm cloud environments with low humidity (RH) of 50%~70%. Inorganic calcium salt can improve the hygroscopic activity of warm clouds at low temperatures of 5℃~15℃, and calcium chloride can reduce the critical humidity for hygroscopic activity to RH 45%. Inorganic magnesium salt prolongs the hygroscopic equilibrium time, avoids rapid evaporation of water droplets, and supports collision and coalescence growth. Inorganic potassium salt adjusts the osmotic pressure of the solution, reduces the surface tension of water droplets by 25% compared with pure water, and promotes the collision and coalescence growth process of small water droplets. Inorganic lithium salt improves the hygroscopic activity in ultra-low humidity environments (RH 30%~50%), and lithium chloride has a hygroscopic capacity of 0.3 g / g at RH 40%. (4) The present invention provides a warm cloud catalyst with high hygroscopicity and low corrosivity. The additives in the catalyst form a hydrophobic film on the surface of its particles, resulting in low agglomeration in a normal humidity RH environment of 60%, and improving fluidity and environmental adaptability. (5) The present invention provides a method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity. The preparation process does not require high temperature and high pressure equipment. The air jet milling process is mature and easy to industrialize. The raw materials are all common chemical products. During air jet milling, the pressure and speed can be adjusted in real time by monitoring the particle size distribution with a laser particle size analyzer according to the target particle size. The cost is lower than that of existing composite catalysts and can meet the needs of large-scale business applications. (6) The present invention provides a method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity. The method can precisely control the particle size of the catalyst and adapt to multiple types of warm clouds: through the “pretreatment sieving-airflow pulverization and classification” process, the particle size of the prepared catalyst can be precisely controlled in the range of 1 μm ~ 15 μm, and the effective particle size ratio is greater than or equal to 90%, which effectively solves the problem of low rain enhancement efficiency caused by the existing catalyst “one-path universal matching”. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments. The embodiments are all based on the technical solutions of the invention and are not intended to limit the patent of the present invention. All modifications and equivalent substitutions within the scope of the principle of the present invention are within the scope of protection.

[0019] In the following embodiments: Double Helix Mixer: Model: SHJ-20, Jiangsu Guibao Group Co., Ltd.; Airflow pulverizer: Model: MQW03, Weifang De'er Powder Equipment Technology Co., Ltd.; Laser particle size analyzer: Model: Mastersizer 300, Malvern Instruments Ltd.

[0020] Example 1 A warm cloud catalyst with high hygroscopicity and low corrosivity, based on a total mass of 100g of the catalyst raw material (100%), wherein all components are powders, and the types and mass fractions of the components are shown in Table 1: Table 1

[0021] A method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity as described in this embodiment, the method steps are as follows: (1) Raw material pretreatment: Sodium chloride, sodium sulfate, magnesium chloride, potassium chloride, lithium chloride, sodium carbonate and sodium borate were placed in an oven and dried at 80 ℃ for 12 h. The salt was then passed through a 40-mesh copper sieve and the residue was collected to obtain the pretreated salt. (2) Premixing: Weigh the pretreated salt from step (1) according to the formula ratio, add it to the double helix mixer, stir at 60 r / min for 20 min until uniform, pass through a 20-mesh copper sieve, take the residue from the sieve, and obtain mixture A; (3) Additive mixing and drying: Add 1.5 g magnesium stearate and 1.5 g silicon dioxide to the mixture A obtained in step (2), and continue to stir in a double spiral mixer at 60 r / min for 10 min until uniform. Pass through a 40-mesh copper sieve, take the residue, transfer to a box, dry at 70 ℃ for 6 h, pass through a 40-mesh copper sieve, take the residue, and obtain mixture B. (4) Airflow pulverization and particle size control: The mixture B obtained in step (3) is fed into an airflow pulverizer. The pulverization pressure is 1.0 MPa and the classifier speed is 4000 r / min to obtain a dry powder product, which is a warm cloud catalyst with high hygroscopicity and low corrosivity.

[0022] The catalyst prepared in this embodiment was vacuum-packed in an aluminum-plastic composite bag with a vacuum degree of -0.1 MPa.

[0023] The catalyst prepared in this embodiment was tested as follows: (1) Particle size distribution: The particle size distribution was measured by a laser particle size analyzer. The particle size distribution was Dv(50) = 3.01 μm and Dv(100) = 9.83 μm. The proportion of medium-sized catalyst particles with a particle size of 5 μm to 10 μm was 91.2%. (2) Moisture absorption performance: According to GB / T 16913-2008 "Test Methods for Physical Properties of Dust - Determination of Moisture Absorption", the moisture absorption of the catalyst under 30℃ and 90% RH conditions is 3145 mg / g, and the moisture absorption of the catalyst under 30℃ and 60% RH conditions is 470 mg / g; (3) Corrosion performance: In accordance with standard CSTM 00046.10-2018 "Corrosion test of low alloy structural steel - Part 10: crevice corrosion test method" and GB10124-88 "Metallic materials laboratory uniform corrosion full immersion test method", distilled water was set as a blank control. The catalyst solution and sodium chloride solution with a mass fraction of 5% were prepared respectively. After immersing 304 stainless steel and 2024 aluminum for 17 days, crevice corrosion appeared in 304 stainless steel in sodium chloride solution. No obvious corrosion traces were found in the blank control and catalyst solution after immersion for 17 days. (4) Anti-caking performance: The catalyst packaged according to this embodiment, after being stored in a 60%RH environment for 6 months, has a caking rate of 7.8% and a flowability (angle of repose 32°) that changes from the initial state (angle of repose 30°) by less than or equal to 6.7%.

[0024] Example 2 A warm cloud catalyst with high hygroscopicity and low corrosivity, based on a total mass of 100g of the catalyst raw material (100%), wherein all components are powders, and the types and mass fractions of the components are shown in Table 2: Table 2

[0025] A method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity as described in this embodiment, the method steps are as follows: (1) Raw material pretreatment: Sodium chloride, calcium chloride, magnesium sulfate, potassium sulfate, lithium sulfate and sodium acetate were placed in an oven and dried at 70 ℃ for 24 h. The salt was then passed through an 80-mesh copper sieve and the residue was collected to obtain the pretreated salt. (2) Premixing: Weigh the pretreated salt from step (1) according to the formula ratio, add it to the double helix mixer, stir at 50 r / min for 30 min until uniform, pass through a 20-mesh copper sieve, take the residue from the sieve, and obtain mixture A; (3) Additive mixing and drying: Add 2 g of ferric ammonium citrate and 3 g of calcium silicate to the mixture A obtained in step (2), and continue to stir at 50 r / min for 8 min in a double spiral mixer until uniform. Pass through a 60-mesh copper sieve, take the residue, transfer it to an oven, dry at 70 ℃ for 6 h, pass through a 40-mesh copper sieve, take the residue, and obtain mixture B. (4) Airflow pulverization and particle size control: The mixture B obtained in step (3) is fed into an airflow pulverizer. The pulverization pressure is 1.2 MPa and the classifier speed is 3000 r / min to obtain a dry powder product, which is a warm cloud catalyst with high hygroscopicity and low corrosivity.

[0026] The catalyst prepared in this embodiment was stored in a nitrogen tank with a purity of ≥99.9%.

[0027] The catalyst prepared in this embodiment was tested as follows: (1) Particle size distribution: The particle size distribution was measured by a laser particle size analyzer. The particle size distribution was Dv(50) = 12.55 μm and Dv(100) = 14.94 μm. The proportion of large-particle catalyst with a particle size of 10 μm ~ 15 μm was 90.5%. (2) Moisture absorption performance: According to GB / T 16913-2008 "Test Methods for Physical Properties of Dust - Determination of Moisture Absorption", the moisture absorption of the catalyst under 30℃ and 90% RH conditions is 2998 mg / g, and the moisture absorption of the catalyst under 30℃ and 60% RH conditions is 520 mg / g; (3) Corrosion performance: In accordance with standard CSTM 00046.10-2018 "Corrosion test of low alloy structural steel - Part 10: crevice corrosion test method" and GB10124-88 "Metallic materials laboratory uniform corrosion full immersion test method", distilled water was set as a blank control. Catalyst solution and sodium chloride solution with a mass fraction of 5% were prepared respectively. After immersing 304 stainless steel and 2024 aluminum for 17 days, crevice corrosion appeared in 304 stainless steel in sodium chloride solution. No obvious corrosion traces were found in the blank control and catalyst solution after immersion for 17 days. (4) Anti-caking performance: The catalyst packaged according to this embodiment has a caking rate of 7.8% after 6 months of storage in a 60%RH environment, and the fluidity (angle of repose 34°) changes by less than or equal to 9.7% from the initial state (angle of repose 31°).

[0028] Example 3 A warm cloud catalyst with high hygroscopicity and low corrosivity, based on a total mass of 100g of the catalyst raw material (100%), wherein all components are powders, and the types and mass fractions of the components are shown in Table 3: Table 3

[0029] A method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity as described in this embodiment, the method steps are as follows: (1) Raw material pretreatment: Sodium chloride, sodium sulfate, calcium sulfate, magnesium sulfate, potassium chloride, lithium sulfate, sodium metasilicate and sodium carbonate were placed in an oven and dried at 100 °C for 6 h. After passing through a 60-mesh copper sieve, the residue was collected to obtain the pretreated salt. (2) Premixing: Weigh the salt pretreated in step (1) according to the formula ratio, add it to the double helix mixer, stir at 70 r / min for 15 min until uniform, pass through a 20-mesh copper sieve, take the residue from the sieve, and obtain mixture A; (3) Additive mixing and drying: Add 0.1 g potassium ferrocyanide to the mixture A obtained in step (2), and continue to stir in a double spiral mixer at 70 r / min for 8 min until uniform. Pass through a 40-mesh copper sieve, take the residue, transfer to an oven, dry at 60 ℃ for 10 h, pass through a 40-mesh copper sieve, take the residue, and obtain mixture B. (4) Airflow pulverization and particle size control: The mixture B obtained in step (3) is fed into an airflow pulverizer. The pulverization pressure is 0.9 MPa and the classifier speed is 5000 r / min to obtain a dry powder product, which is a warm cloud catalyst with high hygroscopicity and low corrosivity.

[0030] The catalyst prepared in this embodiment was vacuum-packed in an aluminum-plastic composite bag.

[0031] The catalyst prepared in this embodiment was tested as follows: (1) Particle size distribution: The particle size distribution was measured by a laser particle size analyzer. The particle size distribution was Dv(50) = 6.78 μm and Dv(100) = 9.08 μm. The proportion of medium-sized catalyst particles with a particle size of 5 μm to 8 μm was 91.5%. (2) Moisture absorption performance: According to GB / T 16913-2008 "Test Methods for Physical Properties of Dust - Determination of Moisture Absorption", the moisture absorption of the catalyst under 30℃ and 90% RH conditions is 3028 mg / g, and the moisture absorption of the catalyst under 30℃ and 60% RH conditions is 430 mg / g; (3) Corrosion performance: In accordance with standard CSTM 00046.10-2018 "Corrosion test of low alloy structural steel - Part 10: crevice corrosion test method" and GB10124-88 "Metallic materials laboratory uniform corrosion full immersion test method", distilled water was set as a blank control. The catalyst solution and sodium chloride solution with a mass fraction of 5% were prepared respectively. After immersing 304 stainless steel and 2024 aluminum for 17 days, crevice corrosion appeared in 304 stainless steel in sodium chloride solution. No obvious corrosion traces were found in the blank control and catalyst solution after immersion for 17 days. (4) Anti-caking performance: The catalyst packaged according to this embodiment has a caking rate of 9.8% in a 60%RH environment, and the flowability (angle of repose 34°) changes by less than or equal to 6.3% from the initial state (angle of repose 32°).

Claims

1. A warm cloud catalyst with high hygroscopicity and low corrosivity, characterized in that: Based on the total mass of the catalyst raw material as 100%, the individual components and their mass fractions are as follows: Inorganic sodium salts 5% ~ 70%, Inorganic calcium salts 0% ~ 15%, Inorganic magnesium salts 5% ~ 30%, Inorganic potassium salts 2% ~ 30%, Inorganic lithium salts 2% ~ 20%, 5% ~ 35% of weak acid-strong base salts Additives 0.1% ~ 5%, All components are powders.

2. The warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 1, characterized in that: Based on the total mass of the catalyst raw material as 100%, the individual components and their mass fractions are as follows: Inorganic sodium salts 25% ~ 70%, Inorganic calcium salts 0% ~ 8%, Inorganic magnesium salts 5% ~ 30%, Inorganic potassium salts 2% ~ 16%, Inorganic lithium salts 2% ~ 20%, 5% ~ 20% of weak acid-strong base salts Additives: 0.1% ~ 5%.

3. A warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 1 or 2, characterized in that: The inorganic sodium salt is at least one of sodium chloride, sodium bromide, and sodium sulfate; The inorganic calcium salt is at least one of calcium chloride and calcium sulfate; The inorganic magnesium salt is at least one of magnesium chloride and magnesium sulfate; The inorganic potassium salt is at least one of potassium chloride and potassium sulfate; The inorganic lithium salt is at least one of lithium chloride and lithium sulfate; The weak acid-strong base salt is at least one of sodium acetate, potassium acetate, calcium acetate, magnesium acetate, sodium phosphate, sodium borate, sodium metasilicate, sodium silicate, sodium carbonate, magnesium carbonate, potassium carbonate, and lithium carbonate. The additive is at least one of magnesium stearate, ferric ammonium citrate, calcium silicate, potassium ferrocyanide, silicon dioxide, and tricalcium phosphate.

4. The warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 3, characterized in that: Inorganic sodium salts are sodium chloride and sodium sulfate; The weak acid-strong base salt is at least one of sodium acetate, sodium borate, sodium metasilicate, and sodium carbonate; The additive is at least one of magnesium stearate, ferric ammonium citrate, calcium silicate, potassium ferrocyanide, and silicon dioxide.

5. A method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity as described in any one of claims 1 to 4, characterized in that: (1) Dry the inorganic salt and the weak acid strong base salt, and then pass them through a 20-100 mesh copper sieve respectively. Take the residue from the sieve to obtain the pretreated salt; the inorganic salt is a combination of inorganic sodium salt, inorganic calcium salt, inorganic magnesium salt, inorganic potassium salt and inorganic lithium salt with a mass fraction of not 0%; (2) Weigh the pretreated salt according to the formula ratio, add it to the mixer and stir evenly; pass it through a 20-mesh copper sieve, take the residue from the sieve, and obtain mixture A; (3) Add additives to mixture A, continue to stir evenly in the mixer, pass through a 20-60 mesh copper sieve, take the residue, dry, pass through a 20-80 mesh copper sieve again, take the residue, and obtain mixture B; (4) The mixture B is fed into an air jet mill. The target particle size is controlled by adjusting the grinding pressure and the speed of the classifier wheel. After grinding, a dry powder product is obtained, which is a warm cloud catalyst with high hygroscopicity and low corrosivity.

6. The method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 5, characterized in that: In step (1), the sample is passed through a copper sieve of 40-80 mesh; drying is carried out in an oven at 70-100℃ for 6-24 hours.

7. The method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 5, characterized in that: In step (2), stir at a speed of 50 r / min ~ 70 r / min for 15 min ~ 30 min.

8. The method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 5, characterized in that: In step (3), add additives to mixture A, continue to stir evenly in the mixer, pass through a 40-60 mesh copper sieve, take the residue, dry, pass through a 40 mesh copper sieve again, take the residue, and obtain mixture B; Continue stirring at the same speed as in step (2) for 8 min ~ 10 min; Drying is carried out in an oven at 60℃~70℃ for 6h~10h.

9. A method for preparing a warm cloud catalyst with high hygroscopicity and low corrosivity according to claim 5, characterized in that: In step (4), the crushing pressure is 0.9 MPa ~ 1.2 MPa and the classifying wheel speed is 3000 r / min ~ 5000 r / min.

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