R From used tyres to rubber powder - MeWa Recycling Maschinen ...

hand. This step is done mechanically in
the course of the process. The final result
is even, approximately hand-sized pieces
of tyre (shreds).
High Purity of Granules
A granulating line then turns these
shreds into very pure granules using the
UNI-CUT ® UG granulators and UNI-CUT ®
USM cutting mills. The tyre pieces are granulated
in several stages to a grain size
between 0 and 4 mm and filled in big
bags ready for sale in three grain sizes
(0 to 0.7 mm, 0.7 to 2 mm and 2 to 4
mm). After every stage the steel is separa-
Cutting mills granule the rubber to a grit size
of less than 4 mm.
The granules is packaged in different
grit sizes – ready for sale.
MeWa-News December 2007
ted using magnets, whilst textile remains
(fluffs) are extracted by suction. After the
last processing stage comes an elaborate
dividing and cleaning process, which
guarantees the highest quality standards
in the end product. The granule purity levels
at the end are around 99.99 per cent
free of steel wire and 99.9 per cent free
of textile fluff.
For refining purposes, a fine rubber
grinding mill can turn the cleaned granules
from a size of 2 to 4 mm into an
active rubber powder (< 1 mm) in a third
processing stage. Active rubber powder
means that this material can be mixed
directly with natural rubber as a secondary
raw material. Depending on the product
and quality level, between 10 and 90 per
cent of this can be replaced.
This finely ground material can currently
be sold on the market at very high
prices, as the demand for substitute na-
Market & trends
tural rubber has grown enormously due
to increasing raw material prices. This
tendency is on the increase because
approximately the same amount of natural
rubber, which tyre manufacturers need
for new production, is also called for in the
market for other products. ■
Pre-shredding.