For the analysis of elemental
composition and/or the mineral content in bulk material the patented
method of "dust sampling" was developed in the Kiruna iron-ore
mine and later on substantiated and verified in lignite mines in Europe.
The sample material is sucked in from the fine grained particle cloud
which usually surrounds the bulk material, while the material is moved
or crushed, and can vary up to 10 mm in grain size. The method is
therefore quick (time for one sample 60 seconds or less) and in most
cases the sample is ready for direct analysis without further
preparatory steps. the sample has - before it is analyzed - a well
defined grain size distribution, which may vary between the different
application cases.
The extracted sample itself must not have the same chemical composition
as the material stream to be analyzed. But of course the information
received from the SOLAS monitoring device must be corresponding to the
whole material stream. Therefore a very large amount of the R&D work
done was related to simple and reliable procedures for establishing and
verifying this correlation. SOLAS is delivered precalibrated.
In contrast to other on-line analyzers (e.g. transmission or excitation
methods) SOLAS delivers a physical sample which may be used for a
variety of additional tests. on the other hand the amount of sample to
be handled is small compared to conventional sample taking procedures. |
SOLAS
is taking a sample using a sampling tube in a region with great particle
density like e.g. in a transfer point. Inside the equipment the particle
stream is passing a filter to obtain an upper grain size cut. Afterwards
the particles are separated from the air stream. In this procedure a
second -lower- grain size cut is done. A sensing device supervises the
sample collection and stops sample-taking as soon as the desired amount
of sample is received. The sample is then transferred into a measuring
chamber with the measuring probe of an XRF-analyzer attached. While the
analysis is in process the next sample is already sucked in and
collected. In this way a quasi-continuous supervision of the material
stream is ensured.
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