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QUOVADIS Project Work Package 6 Task
6.4Validation of prCEN/TS 15413 (WI 343027)
Methods for the preparation of the test sample
from the laboratory sample Part 2 Ruggedness
testing Aldo Giove ENEL GEM Area Tecnica
Ricerca Brindisi (Italy) Roma, 24 October 2007
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Devices for particle size reduction
First step
Final step
or
Retsch SM 2000 Cutting Mill
Retsch SR 300 Rotor Beater Mill
Retsch ZM-1 Centrifugal Mill

• Size reduction by cutting and shearing forces
• Low speed ? low heating
• Final particle size depending on the grid/sieve
  installed coarse to mid size cutting (order of
  magnitude mm)
• Feed soft, medium-hard, tough, elastic, fibrous
  materials
• Low to mid throughput

• Size reduction by hammering, impact and shear
  effects
• High speed ? some heating is developed during
  processing
• Final particle size depending on the grid/sieve
  installed coarse to mid size cutting (order of
  magnitude mm)
• Feed soft, medium-hard low performances on
  tough, elastic and fibrous materials
• Mid to high throughput

• Size reduction by high speed impact and shear
  effects
• High speed ? heating may be developed during
  processing, depending on the type of material
• Final particle size depending on the grid/sieve
  installed mid to fine size cutting (order of
  magnitude below mm)
• Feed soft, medium-hard, brittle, fibrous
  materials
• Low throughput

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Evaluation of the effect of particle size
reduction devices
(D95 0.95 cm)
Analyses CHN 3 replicates each x 15 independent
portions Hg direct 3 replicates each x 15
independent portions Moisture ash 3 replicates
each x 15 independent portions Elements (20, by
alkali fusion and ICP-OES) 3 replicates each x
15 independent portions
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Sub-sampling for evaluation of ruggedness
16 sub-samples (A .. R) of about 50 g each were
already been prepared from 1 kg of material
(D950.95 cm). Five of them (A, D, G, L, O) have
previously been used for the verification of the
statistical formula. The other nine are used for
evaluation of ruggedness B, C, E for low stress
processing F, I, M, for mid stress processing
P, Q, R for high stress processing. Each
sub-sample has been further divided in two
aliquots for the different analytical procedures,
one for CHN and Hg, the other for moisture, ash
and elemental determination.
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Effect of particle size reduction device on
municipal solid waste (QR-D) mass recovery rate
Recovery rate is more quantitative for cutting
mill SM 2000 centrifugal mill ZM 1 (Low
stress processing), while more of 15 of the
mass is lost (as dispersed dust) with the rotor
beater mill SR 300 centrifugal mill ZM 1(Mid"
but expecially High stress processing). Worst
results have been shown by high stress method.

• Definitley low stress processing shows the best
  recovery in both type of samples.
• The temperatures developed during Low stress
  treatment arent enought high to cause significat
  influences on the sample mid- and expecially
  high-stress procedures could influence some
  volatile parameters (i.e. moisture). Low stress
  processing has the smallest influence on the
  samples  characteristics.

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Effect of particle size reduction device
macro-homogeneity on municipal solid waste sample
Analytical results performed on the different
aliquots of sample have been used to evaluete the
actual CV between the macro aliquots
(homogeneity between the test portions of about
15 g each, obtained by combining results of
micro aliquots of 1 g each). A qualitative
comparison of these values shows that for each
parameter the variability between sub-sample
(RSD) is comparable and doesnt show significant
differences due to the processing.
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Effect of particle size reduction device
micro-homogeneity on municipal solid waste sample
Analytical results performed on the different
aliquots of sample have been used to evaluete the
actual CV between the micro aliquots
(homogeneity between all the different test
portions of about 1 g each)
A qualitative comparison of the values shows that
for each parameter the variability between test
portions (RSD) is comparable and doesnt show
significant differences due to the processing
Copper values show extremely high variability
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Application of statistical formula on demolition
wood sample (QR-B)
Case of 16 sub-samples of 55 g each obtained from
the quartering of the original sieved sample,
with a shape factor estimated using the
dimensions 5x0.5x0.4 cm (s 0.008). D95 0.95
cm.
Case of sub-samples of 1 g each (obtained after
further quartering) and a shape factor estimated
using the dimensions 0.5x0.5x0.4 cm (s 0.8)
D95 0.05 cm. (These are the test samples needed
of analytical determinations)

• For major and homogeneously distribuited
  components (high p-factor) a CV of 0.05 or less
  is to be expected.
• For less homogeneously distribuited components
  (small p-factor) a CV of 0.11 or higher is to be
  expected.
• These CV express the level of macro-homogeneity

• For major and homogeneously distribuited
  components (high p-factor) a CV of 0.07 or less
  is to be expected.
• For less homogeneously distribuited components
  (small p-factor) a CV of 0.17 or higher is to be
  expected.
• These CV express the level of micro-homogeneity

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Effect of particle size reduction device
macro-homogeneity and loss of volatiles on
demolition wood sample

• For most parameters the variability is
  significantly affected by the processing low
  stress procedure show generally lower variability
  compared to high and mid stress procedures.
• A notable exception regards Pb is due to a
  sub-sample that has a content ten times higher
  than all others of this element, explained by
  possible presence of a single fragment of
  highly contaminated wood.

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Effect of particle size reduction
devicemicro-homogeneity on demolition wood
sample

• For each parameter the variability (RSD) show
  significant differences due to the processing
  Low and Mid stress procedures differ
  significantly with high stress in the result
  micro-homogeneity (homogeneity between all the
  different test portion of about 1 g)

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Effect of particle size reduction device loss of
volatiles on demolition wood sample
Mid- and high- stress processing could lead to
some loss of volatiles moisture values are
significantly different between the low-stress
processed sample, (treated with cutting mill) and
both other series of sample (treated with rotor
beater mill)
Other parameters dont show significant
differences between low, mid and high stress
treatments
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Considerations on effect of particle size
reduction devices

• Loss of analytes volatile compounds (mainly
  moisture) can be lost due to the system used for
  particle size reduction (this effect was not
  visible in the case of municipal solid waste,
  maybe due to the heterogeneity of sample that
  masks significant differences between the
  procedures). Low stress procedure gives higher
  recovery for moisture compared to the mid and
  high-stress treatment. For all other parameters,
  differences between the three treatment
  procedures are due just to the intrinsic
  heterogeneity of the sample.
• Mass recovery the Low-stress treatment
  procedure shows the best mass recovery (gt 90),
  while the Mid and High stress procedures
  perform somehow worse. This is due to the
  different particle size reduction technology
  used the cutting mill used in the low-stress
  procedure develops less dust during processing
  compared to the rotor-beater mills, so it should
  be preferred when possible.
• Resulting micro-homogeneity and macro-homogeneity
  appear to be influenced in some way by the system
  used for particle size reduction (this effect was
  not visible in the case of municipal solid waste,
  maybe due to the heterogeneity of sample that
  masks significant differences between the
  procedures). Low stress procedure (cutting mill)
  gave slightly better results.

prCEN/TS 15413 (? upgrade to EN 15413)