Water atomizing of metals is now a commercially important methodology to achieve fine particle distribution for a range of materials.
The general process is effective by impinging a falling stream of molten metal with jets of water which immediately solidify the metal into granules (>1mm) or powder (<1mm). Compared to less modern techniques like crushing and grinding water atomization presents a cost effective and efficient approach to producing metallic powders.
Atomization is the most commercially used process to produce the largest tonnage of metal powders. High-pressure water atomization has proven to be a viable, low-cost process to achieve fine particle size distributions for iron, stainless and low-alloy metal powders. The economic advantages and pre-alloying capability provide desirable advantages over competing technologies. Previous shortcomings relative to powder characteristics, i.e. irregular particle shape, lower tap densities, oxidized surfaces, have been refined to more closely replicate gas atomized powder properties.
In principle the technique is applicable to all metals that can be melted, and is commercially used for the production of iron, copper, including tool steels, alloy steels, brass, bronze and the low-melting-point metals, such as aluminum, tin, lead, zinc, cadmium.
If a falling stream of molten metal is impinged by jets of water, then it is broken up into droplets which rapidly freeze to form granules (>1 mm) or powder (<1 mm), depending on the composition of the metal alloy, and the water pressure. Classical granulation uses pressures in the range of 2-5 bars (200-500 kPa) and typically produces 1-10 mm size granules. Very large flow rates can be accommodated (in the t/min range), as pumping costs are modest.
To make finer powders, one needs higher pressures (we find median size is approximately inversely correlated with pressure), so it is necessary to use more controlled streams, typically from a tundish arrangement instead of a launder as in many granulators, and to run more modest flow rates, typically using nozzles from 3 mm to 30 mm in diameter to give flow rates from 5 kg/min to ~500 kg/min (up to 30 t/h). Pressures range from 20 bars for coarser powders (say 0.3 mm) to 200 bars for finer powders (say ~50 μm). Elements like sulphur in the melt strongly affect (reduce) the required pressure by reducing melt surface tension.
As shown in Figure 2, the atomized slurry can be pumped, either directly to leach tanks, or to a dewatering system which can deliver either a thickened slurry at ~20% moisture or a damp solid at ~5% moisture. This can then be fed to the leach tanks if the water balance is critical. Drying adds significant energy and cost, but may be done if, for instance, a smelter is selling to a refiner.
Water atomization has been used in the production of iron/steel powders since the 1950s, following its development in the 1930s for copper powders. Median particle sizes of ~50-100 μm are readily produced from high-purity Fe-0.1-0.3%C melts using pressures of ~100 bars (10 MPa). Today, about 80% of the world's iron powder, some 1 Mt/a, is produced by water atomization, typically using ladle sizes from 30 to 110 t and atomizing speeds of 10-50 t/h.
Hunan skyline smart material&technology Co., Ltd(http://www.skylinesmt.net) has supplied scores of atomizers for all sorts of metals, from copper and silver, to Ni, Co, Fe alloys, including Ag, Au, Pt, Rh, Co, and Ni values, have been supplied. The size of particles requested by clients has ranged from <50 μm to sub-millimetre, and operating pressures have varied from 500 bar (50 MPa) to 20 bar (2 MPa).
Compared to crushing and grinding, atomization has an advantage in lacking any serious wearing parts; the water jets do the work and maintenance costs are modest. The cost of atomization is generally much less than the cost of melting, especially if drying of the product is not necessary, as is normally the case for leaching feeds.
Applications of Powdered Metals:
- Chemical Industries
- Sintering Industries
- Metallurgical Engineering
- Moulds Manufacturing
- Pigments Paste and Flakes
- Flames and Plasma Spraying
- Pyrotechnics
- Diamond Tools
- Refractory Industry
- Brake and Friction linings
- Soldering and Brazing Industry
- Metal Blasting
- Flux Cored Wire
Introduciton
The method of powder atomizing equipment is a kind of new technology in the powder metallurgy industry which was developed in recent years. It is with the characteristics of simple craft, easy to master technology, not easy oxidizing material, and high degree of automation.
Application and Principles
Highpressure water atomization preparation powdered material production line is featured as an equipment,an industrialized mass-production device,designed for producing powder by water atomization under morphemic condition.Its working principle refers to the smelting of metals or metal alloys in air,in which,under the shielding made of inert gas and during the procedure of the metal liquid in insulation tundish flowing downward through fluid-direction tubes,high-pressure water atomizes the liquid metals into a mountain of tiny metal droplets which can form sub-spherical or irregular-shape particles by the combined effects from surface tension and water quick cooling in the flying course of those tiny drops,finally achieving the goal of making powder.
Superiorities and Features
High-pressure water atomization preparation powdered material production line provided by jutatech is equipped with world advanced technologies of this field,primarily processed with following features:
1.The main body of this equipment is structured with nonmagnetic stainless steels,high strength and long lifetime;
2.The furnace sprue gate has no forth-and-back movement,high precision of fixed-point casting;
3.The metal smelting course is protected by inert gas,reducing oxidation;
4.Fast increasing of melting temperature,high production efficiency,good particle size distribution;
5.Hydraulic pressure inclines the furnace,stepless speed regulating,steady and safe;
6.Atomized-water height digital displaying measurement monitoring,atomization parameter steady controlling;
7.The overall device adopts distributed control system,video monitoring for key parts,friendly human-machine interface;
8.Brand-new integrative furnace structure designing,helpful for improving every performance of powder preparation.
9.Security monitoring system for damages on melting crucible,ensuring production safety;
10.Original online particle size monitor and feedback system,precise control on powder quality.
Type: Powder Production Equipment
Input Size: blocks, plates, bars, rods, etc. raw materials in various sizes.
Processed Materials: metals or alloys
Applications: Water atomization powder manufacturing equipment.It's highly recommended for production of iron powder, copper powder, stainless steel powder and alloy powder.
Overview:
The water atomization equipment is the commercially progressive methodology in powder metallurgy industry. This equipment utilizes high velocity water flow to atomize molten metal into powder particles. It's highly recommended for producing iron powder, copper powder, stainless steel powder and alloy powder.
The equipment produces 10~1,000kg powder per batch. It's also can produce alloy powders, such as iron-based powder, nickel-based powder, copper-based powder, silver-based powder, etc. Moreover, customized equipment is also available to cater to customer's specific requirements for batch capacity and particle size.
Features
The atomized powder is irregular with relatively high content of oxygen. Oxygen content can be reduced by the subsequent reduction process.
We also offer the whole water atomizing production line, including water atomization powder manufacturing equipment, reduction furnace, nitrogen circulating system, ball mill machine, sieving machine, mixing machine etc..
Specifications: