Methods for zinc powder preparation

2016-12-23

Zinc powder preparation methods: There are two methods: ball milling and atomization. Ball milling produces coarse zinc powder with a wide particle size distribution, but it has high production efficiency, low energy consumption, and low cost. By strengthening the atomization process and screening and grading technology, finer powder that meets the requirements can also be produced. Atomization produces fine zinc powder with high active metal content. 1. Ball milling method Wet ball milling can prepare zinc powder slurry with a flake structure. The flake structure zinc powder has a large covering power, and the amount of zinc powder used when preparing coatings is less than that of granular zinc powder. Atomized zinc powder and fat

Zinc powder preparation methods:
There are two methods: ball milling and atomization. Ball milling produces zinc powder with coarse particles and a wide particle size distribution, but it has high production efficiency, low energy consumption, and low cost. By strengthening the atomization process and screening and grading technology, finer powder that meets the requirements can also be produced. Atomization produces fine zinc powder with high active metal content.
　　1. Ball milling method
　　Wet ball milling can prepare zinc powder slurry with a flake structure. The flake-structured zinc powder is widely used in the foreign coating industry and has a large covering power, requiring less zinc powder than granular zinc powder when formulating coatings. Atomized zinc powder, aliphatic hydrocarbon solvent, and a small amount of lubricant are placed in a ball mill for grinding. When the required fineness is reached and flake zinc powder is formed, the slurry is discharged for pressure filtration to form a filter cake with a content of 90%, and the filter cake is mixed to form a zinc powder slurry for coatings.
　　2. Atomization method
　　The atomization method for preparing zinc powder has a total of 4 steps:
　　① Zinc melting: The zinc melting equipment can adopt a reverberatory furnace or rotary furnace made of refractory materials. To ensure good fluidity of the zinc solution and facilitate atomization, the melt temperature is around 400-600℃. The fuel used can be coke, fuel oil, or coal gas.
　　② Zinc solution atomization: After melting, the zinc is transferred to a refractory material vortex and atomized under heating and insulation conditions. The nozzle used for atomization is a cast steel disc with many inverted conical holes. The compressed air accelerates at the nozzle outlet, effectively spraying the zinc liquid into a mist. The working pressure of the gas supplied by the air compressor is 3-6 MPa.
　　③ Zinc powder dust collection: When the mist-like zinc powder enters the dust collector, it gradually settles down due to loss of kinetic energy and falls into the concave groove, and is transported out of the dust collector by a spiral discharger.
　　④ Zinc powder screening and grading: The atomized zinc powder transported by the spiral discharger enters the storage bin and continuously falls into a multi-layer vibrating screen. Through the vibration of the screen body, the screen surface with different mesh sizes screens the zinc powder into products of different fineness and moves them into packaging barrels

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