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Quo Vadis work package 4. Sampling and sample preparation By Geert Cuperus (Tauw) TAUW VTT INFA INSTITUTE. Contents. Background The new standard Validation of sampling and sample preparation Ruggedness testing. Background. Inhomogenity is the issue Shape Variability in shape and size
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Quo Vadis work package 4 Sampling and sample preparation By Geert Cuperus (Tauw) TAUW VTT INFA INSTITUTE
Contents • Background • The new standard • Validation of sampling and sample preparation • Ruggedness testing
Background • Inhomogenity is the issue • Shape • Variability in shape and size • Occurance of substances • Many elements occur concentrated in particles • “99% of a substance in 1% of the SRF” • Subsamples keep containing such particles
Background • Many types of SRF exist • Fluff as complex example • Sampling from static lots and stockpiles mostly occur • Sampling consists of a series of steps Sampling Mass reduction Mass reduction Size reduction Analysis
The new standard – EN 15442 • Lot size (period of production) • Number of increments • Size of increments • Distribution of increments • Sample size
The new standard – EN 15442 • Minimum sample size:
Validation of sampling • Procedure: • Five production sites • Samplers (5) apply EN15442 to draft a sampling plan • Sampling (duplicate) of selected batches • Evaluation of plans and sample performance by Tauw • Analysis of elements by one laboratory • Statistical analysis
Sampling at 5 sites Sampler 1 Sampler 2 Sampler 3 Sampler 4 Sampler 5 A A A A A B B B B B Validation of sampling
Validation of sampling SAMPLE PREPARATION • Samples to laboratory: < 5 kg. • Particle size < 30 mm. • Sample preparation = subsampling + comminution • WP4 investigated size reduction by • Quartering • Splitting
Validation of sampling Sample preparation Quartering
Validation of sampling Sample preparation Splitting
Sample 5 sites Primary splitting or quartering Subsample Subsample Secondary splitting or quartering A1 A2 A3 A4 Validation of sampling
Validation of sampling • Field experience: • EN15442 was easy to understand and practicable • Some samplers indicated the standard is too extensive • Useful comments resulted • Proper sampling plans were drafted
Validation of sampling Validation of sampling => total standard deviation Validation of sample preparation => minus sampling Therefore:
Validation testing on sample preparationShare sampling in total repeatability
Validation of sampling • Results were used to adjust EN15442 • Practicable recommendations resulted • Errors of repeatability frequently higher than errors of reproducibility • Repeatability variation frequently negative or >100% • Other sources of error therefore have larger influence
Ruggedness testing • Several method parameters affect the reliability of EN15442 • Of these, the lot size and the number of increments are considered most important
Ruggedness testing on samplingStructure of the investigation • Preparation • Research topics • Parameters: Cl, Hg, Cu, Cr • Sampling focused on influence number of increments (12, 24, 36, 48 and 60) • Sampling focused on influence lot size (500, 1500, 2500, 3500) • Field work at 4 sites (Italy, Norway, Germany, Belgium) • Sample preparation & analysis • Calculation results and reporting
Ruggedness testing Sampling at 4 sites 12 increments 24 increments 36 increments 48 increments 60 increments 5 samples A-E 5 samples A-E 5 samples A-E 5 samples A-E 5 samples A-E
Ruggedness testing Sampling at 4 sites 500 ton 1.500 ton 2.500 ton 3.500 ton 5 samples A-E 5 samples A-E 5 samples A-E 5 samples A-E
Ruggedness testing on sampling Results repeatability versus number of increments
Ruggedness testing on sampling Results repeatability versus lot size
Ruggedness testing • Optimum lot size is 2.500 ton (based on Cl, Hg and Cr) • Optimum number of increments is 36 • However: neither of these parameters dominate the quality of a sample • Therefore 24 increments and lot size 1/10 of annual production can well be applied
Conclusion • Much work has been done now • Go and try the standard for yourself!! THANK YOU