Preparation method of zinc powder

Preparation method of zinc powder:

‍ There are two methods of ball milling and atomization. The zinc powder produced by the ball milling method has coarse particles and wide particle diameter distribution, but has high production efficiency, low energy consumption and low cost. It can also be made into finer powders by strengthening the atomization process and screening and classification technology. . The atomization method produces fine zinc powder particles and high active metal content.

Ball milling

Wet ball milling can prepare zinc powder slurry with scale structure. The foreign coating industry has widely used zinc powder slurry with granular structure. The zinc powder with scale structure has greater hiding power. When the coating is used, the amount of zinc powder is less than granular. Zinc powder. The atomized zinc powder and the aliphatic hydrocarbon solvent and a small amount of the lubricant are ground in a ball mill to achieve the required fineness and the scale slurry is formed to discharge the slurry to form a filter cake having a content of 90%, and the filter cake is mixed. It is a zinc powder slurry for coatings.

2. Atomization method

There are four steps in the preparation of zinc powder by atomization:

1Metal zinc melting: The molten zinc equipment can adopt the reverberatory furnace or converter made of refractory material. In order to make the zinc solution have good fluidity and easy atomization, the temperature of the molten metal is about 400-600 °C, and the fuel used can be coke, fuel or gas.

2 Zinc solution atomization: After the zinc is melted, it is transferred into the refractory tree vortex, and atomized under heating and heat preservation conditions. The nozzle for atomization is a cast steel disc, which has many round holes with inverted cones, and the compressed air is in the nozzle. Acceleration at the outlet end effectively sprays the zinc liquid into a mist, and the working pressure of the gas supplied by the air compressor is 3-6 MPa.

3 Zinc powder dust collection: When the misty zinc powder enters the dust box, it gradually deposits due to the loss of kinetic energy, falls in the groove, and is transported out of the dust box by the spiral discharge device.

4 Screening and grading of zinc powder: The atomized zinc powder delivered by the spiral discharger enters the storage bin and continuously falls into the multi-layer vibrating screen. Through the vibration of the sieve body, the sieve surface of different meshes divides the zinc powder sieve into products of different fineness and moves into the packaging drum.