Iron Powder for Filtration
Hot Polymer Filtration/ Oil Filtration
Because of its unique shape and particle sizes, shattered metal can provide filtration characteristics unlike any other media. Optimum spin pack performance can be achieved through the proper selection of powder size, alloy and bed depth. Careful consideration must also be given to the companion filter media used to ensure that each media compliments the metal powder and contributes to the overall performance of the spin pack.
Metal Powder Selection
Shattered metal powder is most often used in polyester and nylon applications where the shearing of gels is critical. This gel removal is made possible by the near razor-sharp edges and high degree of tortuosity of the powder. The powder also serves as a pack body volume reducer to limit polymer residence time and the risk of polymer degradation.
The main features for a cost-effective quality filter media are:
- High porosity maintained during filtration cycle
- Large active surface area
- No chemical reaction with the polymer
The powder solution fulfills all the above requirements.
Application Examples
A wide range of stainless steel- and super alloy powders for hot polymer filtration are available in bulk quantities. The different grades are designed to meet the various requirements of specific filters. The metal powder filter pack should contain two or three layers of the different powder grain sizes. The best combination depends mainly on the type of polymer used in the spinning process and the extrusion velocity.
Features and Benefits
Stainless steels and super alloy powders possess excellent properties for hot polymer filtration. They do not react chemically with the polymers and they are strong enough to minimize compaction during filtration.
The powder processing – high-pressure water atomization – results in extremely irregular shaped particles. Irregular shapes provide large active surface areas, which ensure good cleaning during filtration and a porous structure with deep filtration properties that remains unchanged during the filtration cycle. Additionally, the powders are not so hard, which prevents brittleness and thereby nozzle clogging. All these factors combine to make our products for spin packs a cost-effective solution for the hot polymer filtration industry
Product Examples
Available types of filter cut materials
P-270 is a modified austenitic stainless steel material especially developed for polymer filtration. Compared to 316L, it offers a somewhat higher Cr, Si and C content.
Fe bal – 20 % Cr – 11 % Ni – 2.5 % Si – 2.5 % Mo.
DP-1 is a nickel-free ferrite stainless steel.
Fe bal – 35 % Cr – 2.5 % Si.
P-271 is a nickel-based super alloy (type IN 600). The material is low in Fe and extremely resistant to oxidation. The powder has been specially developed for the spinning of nylon yarn.
Ni bal -15 % Cr – 7 % Fe.
Typical Physical Properties
| Size (micron) | Size (mesh) | Apparent Density g/cm³ | Tap Density g/cm³ | Porosity |
|---|---|---|---|---|
| 45-90 | 170/325 | 2.7 | 3.5 | 55 |
| 90-125 | 120/170 | 2.3 | 3.1 | 58 |
| 125-180 | 120/80 | 2.2 | 3.0 | 61 |
| 180-250 | 60/80 | 2.1 | 2.8 | 64 |
| 250-355 | 45/60 | 2.0 | 2.6 | 66 |
| 355-500 | 35/45 | 1.8 | 2.2 | 71 |
| 500-850 | 20/35 | 1.8 | 2.1 | 73 |
| 850-2000 | 10/20 | 1.6 | 1.9 | 75 |
Alternative Cuts
| 150-300 | 50/100 | 1.7 | 2.1 | 73 |
| 180-425 | 40/80 | 1.7 | 2.0 | 74 |
| 250-600 | 30/60 | 1.6 | 1.9 | 74 |
| 300-700 | 25/35 | 1.6 | 1.8 | 75 |
| 700-2000 | 10/25 | 1.5 | 1.8 | 76 |