Ultrafine powder non-immersion feeding device and method

Abstract

The present invention relates to a non-immersion feeding device for ultrafine powders, comprising a powder silo, an agitator, a special pipeline, a valve, a positive pressure system and a micro-negative pressure system; the powder silo is arranged higher than the agitator, and the two are connected by a special pipeline, the special pipeline consisting of a section of pipeline with an angle of less than 5° to the horizontal and a section of pipeline with an angle of 45° to 90° to the horizontal; a horizontal baffle and a vertical baffle are arranged at the outlet of the special pipeline facing the direction of the ceramic filter membrane, and a gap is left between the horizontal baffle and the vertical baffle; a first valve is provided at the outlet of the powder silo; a micro-negative pressure system with a ceramic filter membrane is installed on the side wall of the agitator, and a positive pressure system is installed on the top of the agitator and near the ceramic filter membrane on the side wall. The beneficial effects of the present invention are: the present invention adopts gas protection such as nitrogen and argon, micro-negative pressure conveying, positive pressure purging, and combines a special pipeline structure to realize non-immersion feeding of solid ultrafine powders in a non-open agitator, minimizing the aggregation of ultrafine powders during addition or reaction.

Description

Technical Field

[0001] This patent relates to the field of ultrafine powders, and in particular to a non-immersion feeding device and method for ultrafine powders. Background Art

[0002] During material synthesis, due to limitations in raw material formulations and processes, certain ultrafine powders may be used to replace liquid solutions in order to achieve comparable results. For example, in the preparation of specialty ceramics, finer-particle alumina and silica may be used in place of aluminum nitrate and organosilicon sources to reduce porosity or cracks caused by the release of organic matter during the subsequent calcination process. Alternatively, in some low-volume systems or where volume control is strictly required, solid powders may be added to reduce system volume.

[0003] During the process of adding powder, the system temperature may rise due to the exothermic dissolution or reaction of the previously added drugs. The subsequently added powder will float and suspend above the liquid surface, making it difficult to fully mix with the liquid phase, which will inevitably cause waste of raw materials. Moreover, if the system is closed, the risk of dust explosion will increase to a certain extent.

[0004] With tightening environmental standards and safety concerns, ultrafine powders are generally added in closed systems. Therefore, adding ultrafine powders directly below the liquid level in the reaction system will cause the particles to quickly aggregate and clump, affecting mixing or reaction performance. Therefore, using gas delivery can reduce this problem.

[0005] In view of this, it is very important to realize the safe and effective non-immersion feeding of ultrafine powders. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a non-immersion feeding device and method for ultrafine powders.

[0007] This non-immersion feeding device for ultrafine powders includes a powder silo, an agitator, special pipes, valves, a positive pressure system and a micro-negative pressure system; the powder silo is arranged higher than the agitator, and the two are connected by a special pipe, which consists of a pipe section with an angle of less than 5° to the horizontal and a pipe section with an angle of 45° to 90° to the horizontal; a horizontal baffle and a vertical baffle are arranged at the outlet of the special pipe facing the ceramic filter membrane, and a gap is left between the horizontal baffle and the vertical baffle; a first valve is provided at the outlet of the powder silo; a micro-negative pressure system with a ceramic filter membrane is installed on the side wall of the agitator, and a positive pressure system is installed on the top of the agitator and close to the ceramic filter membrane on the side wall; a third valve is provided on the pipe of the positive pressure system, and a second valve is provided on the pipe of the micro-negative pressure system.

[0008] Preferably, the vertical baffle is a height-adjustable baffle.

[0009] Preferably, a grounding wire is installed on the special pipe.

[0010] Preferably, the ceramic filter membrane is located below the pipe opening of the positive pressure system, and the filtration accuracy of the ceramic filter membrane is less than 0.05 μm.

[0011] The method for feeding ultrafine powder into a non-immersion feeding device comprises the following steps:

[0012] S1. After adding the ultrafine powder into the powder silo, close the third valve, open the first and second valves, turn on the protective gas and micro-negative pressure system, and start adding the powder; the degree of negative pressure in the system is related to the particle fineness;

[0013] S2. Under the action of gravity, slight negative pressure and protective gas, the powder enters the liquid surface along a special pipe. The powder silo is set slightly higher than the agitator. The two are connected by a pipe with an angle of less than 5° to the horizontal and a pipe with an angle of 45° to 90° to the horizontal. The outlet of the special pipe is equipped with horizontal and vertical baffles facing the ceramic filter membrane to prevent the powder from flowing back along the pipe to the greatest extent. A gap is left between the horizontal and vertical baffles.

[0014] S3. After the powder is added, close the first valve, increase the amount of protective gas introduced, and purge the pipeline;

[0015] S4. After the pipeline is purged, close the second valve, open the third valve, start the positive pressure system, and purge the ceramic filter membrane.

[0016] Preferably, in step S1, the protective gas is one or more gases such as nitrogen, argon or carbon dioxide.

[0017] The beneficial effects of the present invention are: the present invention adopts gas protection such as nitrogen and argon, slightly negative pressure conveying, positive pressure purging, and combines a special pipeline structure to realize non-immersion feeding of solid ultrafine powder in a non-open agitator, thereby minimizing the aggregation of ultrafine powder during the addition or reaction process, and has the advantages of saving materials and fully mixing solid and liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the non-immersion feeding device for ultrafine powders.

[0019] Description of the accompanying drawings: powder silo 1, agitator 2, horizontal baffle 3, vertical baffle 4, ceramic filter membrane 5, first valve 6, second valve 7, third valve 8. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the following examples. The following examples are provided only to facilitate understanding of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications fall within the scope of the claims of the present invention.

[0021] This patented device utilizes nitrogen, argon, and other gas shielding, along with slightly negative pressure conveying and positive pressure purging, combined with a special piping design to enable non-immersion feeding of solid particles with a particle size of 0.05 to 100 μm into a non-open agitator. This device and process offers advantages such as material conservation, safe operation, and thorough mixing of solids and liquids. It is suitable for feeding ultrafine powders such as silica, matting powder, kaolin, hydrotalcite, silica powder, aerogel powder, and ceramic additives during mixing or reaction with liquids.

[0022] Example 1

[0023] Embodiment 1 of the present application provides a non-immersion feeding device for ultrafine powders, including a powder silo, an agitator, a special pipeline, three valves, a positive pressure system, a micro-negative pressure system, and a grounding device. The powder silo is set slightly higher than the agitator, and the two are connected by a special pipeline. The special pipeline consists of a pipeline with an angle of less than 5° to the horizontal and a pipeline with an angle of 45° to 90° to the horizontal. A horizontal baffle and a vertical baffle are set at the outlet of the special pipeline facing the ceramic filter membrane, with a gap left between the horizontal baffles to prevent the powder from flowing back along the pipeline to the greatest extent. Among them, the vertical baffle is a height-adjustable baffle that can be adjusted up and down above the liquid surface so that the powder can be added almost perpendicular to the liquid surface. A grounding wire is added to the special pipeline to prevent dust explosions during the feeding process. A first valve is provided at the outlet of the powder silo. A micro-negative pressure system with a ceramic filter membrane is installed on the side wall of the agitator, and a positive pressure system is installed on the top of the agitator and close to the ceramic filter membrane on the side wall. The micro-negative pressure is turned on when feeding and the positive pressure is turned on when purging. A third valve is provided on the pipeline of the positive pressure system, and a second valve is provided on the pipeline of the micro-negative pressure system. The ceramic filter membrane is located below the pipeline outlet of the positive pressure system, and the filtration accuracy of the ceramic filter membrane is less than 0.05μm.

[0024] Example 2

[0025] A second embodiment of the present application provides a method for feeding an ultrafine powder non-immersion feeding device, comprising the following steps:

[0026] 1) Add ultrafine kaolin to the powder silo, close the third valve, start the protective gas nitrogen, open the second valve, and start the micro-negative pressure system. Open the first valve, and the kaolin powder will be transported to the agitator through a special pipeline under the action of the protective gas and the system's micro-negative pressure. Adjust the height of the vertical baffle at the pipeline outlet and the degree of negative pressure to ensure that the powder is added to the liquid phase approximately vertically.

[0027] 2) After the powder is added, close the first valve, increase the amount of protective gas nitrogen, and purge the special pipeline.

[0028] 3) After the purge is completed, close the second valve, open the third valve, start the positive pressure system, and purge the ceramic filter membrane.

Claims

1. A method for feeding ultrafine powder into a non-immersion feeding device, characterized in that: It includes a powder silo, an agitator, a special pipeline, a valve, a positive pressure system and a micro-negative pressure system; the powder silo is set higher than the agitator, and the two are connected by a special pipeline, which consists of a pipeline with an angle of less than 5° to the horizontal and a pipeline with an angle of 45° to 90° to the horizontal; a horizontal baffle and a vertical baffle are set at the outlet of the special pipeline facing the ceramic filter membrane, and a gap is left between the horizontal baffle and the vertical baffle; a first valve is provided at the outlet of the powder silo; a micro-negative pressure system with a ceramic filter membrane is installed on the side wall of the agitator, and a positive pressure system is installed on the top of the agitator and near the ceramic filter membrane on the side wall; a third valve is provided on the pipeline of the positive pressure system, and a second valve is provided on the pipeline of the micro-negative pressure system; the vertical baffle is a height-adjustable baffle; the ceramic filter membrane is located below the pipeline outlet of the positive pressure system, and the filtration accuracy of the ceramic filter membrane is less than 0.05μm; The following steps are involved: S1. After adding the ultrafine powder into the powder silo, close the third valve, open the first and second valves, turn on the protective gas and micro-negative pressure system, and start adding the powder; S2. Under the action of gravity, slight negative pressure and protective gas, the powder enters the liquid surface along a special pipe. The powder silo is set higher than the agitator. The two are connected by a pipe with an angle of less than 5° to the horizontal and a pipe with an angle of 45° to 90° to the horizontal. The outlet of the special pipe is equipped with horizontal and vertical baffles facing the ceramic filter membrane, with a gap between the horizontal and vertical baffles. S3. After the powder is added, close the first valve, increase the amount of protective gas introduced, and purge the pipeline; S4. After the pipeline is purged, close the second valve, open the third valve, start the positive pressure system, and purge the ceramic filter membrane.

2. The method for feeding ultrafine powders using a non-immersion feeding device according to claim 1, characterized in that: A grounding wire is installed on the special pipe.

3. The feeding method of the ultrafine powder non-immersion feeding device according to claim 1, characterized in that: In step S1, the protective gas is one or more of nitrogen, argon or carbon dioxide.

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