Bonded Particle Filter - Pyrotek

At Metaullics, we analyse your process in detail. Only then can we
determine the correct filter and specify the proper shape, size and
permeability for your specific application. Once this has been
done, you can expect trouble-free service life from your
Metaullics® filters.The media we use, bonded ceramic particulate,
provides high filtration efficiency and excellent structural strength.
Our media is used in selected wrought casthouse applications to
produce semi-finished shapes, and in aluminium gravity casting
(permanent mold), pressure diecasting, low pressure, squeeze cast
and high-performance sand foundries.
Because filtration of aluminium is a complex subject, we hope the
information in this brochure will prove useful. Let’s begin with a
look at what effective filtration should accomplish for you
1.1 INCLUSIONS TO BE REMOVED
Filtration is the separation of solids from liquids. Effective filtration
should trap and hold the major contaminants that are commonly
found in molten aluminium. Oxides of aluminium and magnesium
are among the inclusions most frequently encountered. Of these
Al2O3 is the most troublesome, because it is the most easily
formed, hence, the most abundant. Furthermore, many inclusions
have an effective specific gravity close to that of molten aluminium
and tend to stay in suspension. Spinel, another kind of
contaminant, is a complex oxide with a specific crystal structure
and the general chemical formula of AB2O4 where A and B are
metals. Common examples of spinels are MgAl2O4 and MnAl2O4.
Other inclusions to be found include carbides (especially from
primary aluminium production), nitrides, and refractory particles
from wear and erosion. In foundry alloys, especially diecasting
metal, intermetallic sludge particles (Fe-Mn-Cr complex) can
cause ‘hardspots’ which cause machining difficulty. Additionally,
recycled metal in any remelt operation always contains substantial
oxide content