CPT International 01/2017

tems could be dispelled in recent years.
Success stories are setting precedents
and are being shared among foundries
around the world. Many well-known,
globally positioned foundries are now
turning to “inorganic binders” and investigating
the feasibility of changing
their technology.
In other major industrial countries,
too, rising energy costs and a growing
awareness of environmental issues
have triggered a rethink in the foundry
industry. Stricter emission standards
are also becoming a driver for product
and process innovations in Asia, for example.
In pursuit of sustainable production
processes and better working
conditions, there has been increased
interest in core production processes
other than the organic processes,
which have so far dominated.
The sales volume of inorganic binder systems has grown strongly over the
last 10 years
Clear environmental,
The principle of core production using
Hüttenes-Albertus’ inorganic
binder system is based on water glass;
however, it is far superior to the water
glass binders of the past. The inorganic
Cordis binder is a modified silicate
solution mixed with core sand and the
additive Anorgit. In heated core boxes,
this mixture is cured to form a three-dimensional
cross-linked matrix, which
gives the sand core its strength. In addition,
the cores are gassed with air,
heated to 130 °C. The water in the
cores changes into the gas phase and
is expelled. The curing process involves
only heat and the elimination of the
water solvent.
As no combustion products are generated
during curing, there are no emissions,
i.e. no fumes, no BTX or BTEX,
no amines, no odours. Carbon dioxide
emissions are also greatly reduced.
Moreover, there are no condensate deposits
on the mold, which extends the
useful life of the tool. Due to the endothermic
behaviour of inorganically
bound cores, the material properties
can also be precisely controlled in
the aluminium casting. HA’s inorganic
core process allows the production of
high-quality cast parts and the ability
to create complex core geometries – as
well as outstanding cast quality. Inorganic
cores – also uncoated – are used
for cast surfaces, which are on par with
those produced by organic processes,
and sometimes even better.
In addition to environmental and
production-related benefits, the sys-
Europe
Asia
7.000.000
400.000
Quantity [kg]
Quantity [kg]
Rest
~ 100.000 kg
America
500.000
Quantity [kg]
Figure 2: Use of inorganic binder systems worldwide
Casting Plant & Technology 1 / 2017 11