Application of ultrasonic sieving equipment in production of ultrafine zinc powder

Superfine zinc powder is a gray metal regular spherical fine powder produced by distillation in a uniquely designed zinc powder furnace with a density of 7.14g/cm3, melting point of 419 degree and boiling point of 907 degree . Insoluble in water, soluble in acid and alkali, ammonia water, with strong reducibility. It has the advantages of high activity, good corrosion resistance, environmental protection, less surface oxidation, smooth and neat spherulite surface, good dispersity, uniform particle size, large specific surface area, small loose weight, high coating covering efficiency, good chemical reduction effect and so on. Stable in dry air, easy to agglomerate in humid air, and form basic carbonate and cover the surface of particles. Its average particle size is between 3 and 4UM. As the key raw material of zinc-rich anticorrosive coating, it is widely used in coating of large steel components that are not suitable for hot plating and electroplating, such as large outdoor steel structures, ocean engineering, Bridges, pipelines, ships and containers, etc. In addition to being used for zinc-rich anticorrosive coating, zinc powder products are also used for mechanical galvanized production of steel products such as screws, nails and nails. With the development of China's economy, the demand for ultrafine zinc powder has also increased sharply, so the demand for ultrafine zinc powder special sieve is increasingly strong. But in the early 1990s, China's ultrafine screening equipment is almost entirely imported, but there is no ultrafine zinc powder special sieve, which directly increases the cost of ultrafine zinc powder, reduce the profits of enterprises.

Many manufacturers choose air flow screen to screen zinc powder, the principle of air flow is by high-speed rotation of the sorting wheel, to distinguish the fineness of zinc powder: classification wheel and fixed part of the gap is very small, is the heating zone, when the active zinc powder will become molten agglomerate, and even combustion. Caking will make the product unqualified, and zinc powder can not burn open fire, not easy to find, sometimes until very serious found fire, heavy losses. Not only will the whole equipment be scrapped, but there is no safety guarantee.

Our company after years of research, on the basis of airflow screen, combined with the actual needs, for the characteristics of zinc powder a new screening equipment, zinc powder will not be heated agglomerate or spontaneous combustion in the sieve machine. This screening equipment is composed of host and aggregate dust removal system, negative pressure cycle work, no dust; There is a layer of coarse selection of raw materials into the host, which overcomes the problem of large particles breaking the net; The raw material enters the atomizing area after atomizing evenly to the 500 mesh screen spray, the negative pressure air passage through the net into the collector, through the closed air wring cage discharged the finished product packaging, but the net is sent to the bottom of the screen plate under the whirlwind cleaning; At this time, there is a little fine powder also down, will be turned up by the secondary air selection system, sprayed again on the 500 mesh screen; Finally, the screen is vibrated to the coarse material outlet, waiting for a certain amount of negative pressure to overcome, automatically open the negative pressure door, discharge. The precision of coarse powder is generally between -200 mesh plus 500 mesh, the effect is very obvious.