QUOVADIS workshop, October 24, 2007 1 QUOVADIS Project Quality Management Organisation, Validation...

QUOVADIS workshop, October 24, 2007 1

QUOVADIS ProjectQuality Management Organisation, Validation of standards,

Developments and Inquiries for SRF

Work Package 6 – Deliverable D6.3“Ruggedness testing on chemical parameters”

Roma, 24 October 2007Dott. Federico Baglivi

([email protected]; [email protected])


Objectives

Evaluation of robustness of Technical Specifications for chemical parameters, as developed by CEN TC 343 WG5, through ruggedness testing on selected reference materials, in particular:

• prCEN/TS 15407 (WI 343020) Methods for the determination of carbon (C), hydrogen (H) and nitrogen (N) content

• prCEN/TS 15408 (WI 343022) Methods for the determination of sulphur (S), chlorine (Cl), fluorine (F) and bromine (Br)

• prCEN/TS 15410 (WI 343024) Method for the determination of the content of major elements (Al, Ca, Fe, K, Mg, Na, P, Si, Ti)

• prCEN/TS 15411 (WI 343025) Methods for the determination of the content of trace elements (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Tl, V and Zn)

• prCEN/TS 15412 (WI 343026) Methods for the determination of metallic aluminium


Ruggedness testing for main factors influencing the procedures for the determination of chemical parameters

• Key variables must be selected among the main degrees of freedom of each method

• For each key variable, conservative conditions should be met; i.e. when the methods “passes” the ruggedness testing in those conditions, it will be actually “robust” in most real life cases.

• The kind of sample to be assigned to each method should emphasize the influence of the key variable under control

Criteria for the selection of sample/variable pairs for the evaluation of ruggedness:

Robustness is the ability of a method to give consistent results under controlled variations of key analytical parameters/conditions

QUOVADIS workshop, October 24, 2007

Shredded tyre (QR-A)

Materials used for Ruggedness and Validation

Demolition wood (QR-B) Dried sludge (QR-C) dried waste water sewage

sludge,filtercake and coal or lignite residues

Dried SBS-1® (QR-D)Combustible fraction of municipal solid waste.

Paper/plastic Fluff (QR- E) Industrial non hazardous waste like a combination of plastic, cardboard and

paper


prCEN/TS 15407 Methods for the determination of carbon (C), hydrogen (H) and nitrogen (N) content

QR-A Shredded tyres sample3Grain size

5

QR-A shredded tyre sampleQR-C dried sludge sampleQR-E paper plastic fluff sample

3CompositionFlash combustion

Total levelsNotesNo of levelsKey variablesMethod

Activity performed at VTT

1.complete oxidation of sample (“flash combustion”):organic substance combustion products

2.Reduction and separation on analytes: Combustion gases reduction furnace separated in a chromatographic column

3. Detection by instrumental gas analysis procedures (i.e. thermal conductivity detector (TCD))



For nitrogen, the average values at 0.5 mm tend to be higher than at larger grain sizes suggesting a higher relative recovery.

RSD values are generally good, and appear to be higher at 1mm grain size

Effect of grain size (QR-A shredded tires - 4 independent replicates)

0

1

2

3

4

5

6

7

8

C/10 H N

con

c %

QR-A 0.5mm

QR-A 1mm

QR-A 1.5mm

Carbon concentration is shown divided by 10 in order to better compare values at the same scale



The results clearly show that for “difficult” samples such shredded tires, the RSD% values are higher while for the other investigated SRFs the RSD values are lower than 5%.

The RSD values are higher for N due to the lower concentration level comparing to C and H.

Effect of sample type / matrix on repeatability1 mm grain size (for sample QR-C only a fine grain size was available due the origin of the sample itself).

For CHN analysis on 1 mm grain size is adequate for most cases for the analysis of SRF samples of different origin, even if better results can be obtained in terms of precision by using larger amounts or lower grain size.

0

2

4

6

8

10

12

14

C H N

RS

D %

QR-A 1mm

QR-A2 1mm

QR-E 1mm

QR-C

Shredded tiresShredded tiresPaper-plastic fluffDried sludge


prCEN/TS 15408 Methods for the determination of sulphur (S), chlorine (Cl), fluorine (F), bromine (Br)

QR-E paper plastic fluff sample3grain size

5

QR-A shredded tyre sampleQR-C dried sludge sampleQR-E paper plastic fluff sample

3compositionCombustion

Total levelsNotesNo of levelsKey variablesMethod

1.Oxidation by combustion in a bomb containing oxygen under pressure: Halogenated and sulphur compounds fluorine, chlorine, bromine and sulphate

2. Adsorption solution

3.Determination by ion chromatography techniques

Activity performed at CESI

Note:

For QR-A (shredded tires): problems in preparation of pellets (breaking during combustion) modifications to the method for these matrices


prCEN/TS 15408 Methods for the determination of sulphur (S), chlorine (Cl), fluorine (F), bromine (Br)

• Recovery appear to be influenced only for sulfur, while for chlorine no clear statements can be done, because of repeatability issues due to heterogeneity of sample.

• Repeatability is worse at larger grain size for Br and Cl, while it is similar for S. In the case of F the situation is more difficult to explain, with RSD value decreasing from 0.5 to 1 mm, and increasing from 1 to 1.5 mm grain size.

A better repeatability is observed in the case of dried sludge, all RSD value are lower than 5%. This result could due to a fixed finer grain size, but also to a less complex matrix.

0

5

10

15

20

25

F Br Cl S

RSD

(%

)

QR-E (0,5 mm)QR-E (1,0 mm)QR-E (1,5 mm)

Effect on repeatabilityEffect on recovery QR-E: paper-plastic fluff – effects of grain size

0

100

200

300

400

500

600

F Br Cl /10 S/10

mg

/kg

QR-E 0.5mmQR-E 1.0mmQR-E 1.5mm


prCEN/TS 15408 Methods for the determination of sulphur (S), chlorine (Cl), fluorine

(F) and bromine (Br) content

Paragraph TypeComment

(justification for change)Proposed change

1 Scope

Te Robustness study shown thatthe method is not applicable inits current form to samplescontaining tyre pieces becausethe prepared pellet tend tobreak during combustion.An alternative method isproposed in Annex B (informative),that is currently not validated.

Add the sentence:this method is not applicable onsamples containing rubber because itis not possible to prepare suitablepellets for the combustion; for thesecases a possible alternative method isdescribed in Annex B (informative).

9.2 SamplePreparation

Te Repeatability for chlorinedetermination is stronglyinfluenced by particle size

After 2nd paragraph add the sentence:Finer particle size (e.g. 0.5 mm) will makebetter repeatability of analysis especiallyfor chlorine.

9.3 Bombcombustion

Te Same as scope. After 3rd paragraph add the note:this method is not applicable on samplescontaining rubber because it is notpossible to prepare suitable pellets for thecombustion; for these cases a possiblealternative method is described in Annex B(informative).


prCEN/TS 15408 Methods for the determination of sulphur (S), chlorine (Cl), fluorine (F)

and bromine (Br) content



Annex B(new)

Te Robustness study shown thatthe method is not applicable inits current form to samplescontaining tyre pieces becausethe prepared pellet tend tobreak during combustion.An alternative method isproposed in Annex B (informative),that is currently not validated.

Annex B (informative) – Alternative method for combustion ofsamples containing tyre pieces. Samples containing tyre pieces show the tendency to break during the combustionphase, so some fragments of the pellet might fall into the absorbing solution and consequently oxidation is not quantitative. Such samples can be oxidized with a modification of the method, that avoids the use of absorbing solution inside the bomb.Instead of applying the method at point 9.3“Bomb combustion”, proceed as follows:Insert the pellet then fill the bomb withoxygen and set up the system followingthe operator instructions. After combustionmake a slow scrubbing of the gas into anabsorbing alkaline solution. Determinate analyte by using the proper method.This alternative method is currently notvalidated.


prCEN/TS 15410 Method for the determination of the content of major elements (Al, Ca, Fe, K, Mg, Na, P, Si, Ti)

5QR-E paper plastic fluff sample4time of heatingMethod C (perchloric acid at 190

°C) + ICP-OES/MS QR-E paper plastic fluff sample2grain size

2QR-E paper plastic fluff sample2grain sizeMethod B - Ashing (prCEN/TS 15403) + ASTM D4326 (XRF)

3QR-A shredded tyre sample3grain sizeMethod B - Ashing (prCEN/TS 15403) + EN 13656 + ICP-OES/MS

QR-E paper plastic fluff sample3+3grain size

QR-E paper plastic fluff sample3+3amount of test portion

8+8

QR-A shredded tyre sampleQR-B demolition wood QR-C sample dried sludge sampleQR-E paper plastic fluff sample

4+4compositionMethod A - EN 13656 (aqua regia + HF + boric, microwave) + ICP-OES/MS

+Method D - EN 13657 (aqua regia only, microwave) + ICP-OES/MS

Total levels

NotesNo of Levels

Key variablesMethod


prCEN/TS 15411 Methods for the determination of the content of trace elements (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se,

Tl, V and Zn)

5QR-D MSW sample3amount of test portion

Hg direct - AMAQR-D MSW sample3grain size

5QR-E paper plastic fluff sample4time of heatingMethod C (perchloric acid at

190 °C) + ICP-OES/MS QR-E paper plastic fluff sample2grain size

3QR-A shredded tyre sample3grain sizeMethod B – Ashing (prCEN/TS 15403) + EN 13656 + ICP-OES/MS

QR-E paper plastic fluff sample3+3grain size

QR-E paper plastic fluff sample3+3amount of test portion

8+8

QR-A shredded tyre sampleQR-B demolition wood QR-C sample dried sludge sampleQR-E paper plastic fluff sample

4+4composition

Method A - EN 13656 (aqua regia + HF + boric, microwave) + ICP-OES/MS

+Method D - EN 13657 (aqua regia only, microwave) + ICP-OES/MS

Total levels

NotesNo of Levels

Key variablesMethod


prCEN/TS 15410 - prCEN/TS 15411 Method A - EN 13656 (aqua regia-HF-boric, microwave)

Activity performed at ENEL

No significant influence in recovery. Larger amount of test portion gives generally lower RSD values.

Same behavior for minor elements (prTS 15411)

variable: amount of test portion

0

0.2

0.4

0.6

0.8

1

Al Ca Fe K Mg Na P Si Ti

Co

nc

%

QR-E 0.1g

QR-E 0.2g

QR-E 0.4g

variable:grain size

0

0.2

0.4

0.6

0.8

1


Co

nc

%

QR-E 0.5mm

QR-E 1mm

QR-E 1.5mmEffect of grain size (QR-E – paper-plastic fluff)

Effect of amount of test portion (QR-E –Paper plastic fluff)

Some influences can be observed for someelements, but they don't appear to be dramatic.



Method A results to be applicable for each kind of matrix tested; higher values of RSD are explained by intrinsic heterogeneity of samples.


• Samples: QR-A (shredded tyre), QR-B (demolition wood), QR-C (sludge) and QR-E (paper-plastic fluff)

• Test portion: 0.2 g • Grain size: 1 mm, except QR-C dried sludge (finer).

EN 13656

variable: composition

0

5

10

15

20

25

30

35

40


RS

D %

QR-E QR-A

QR-B QR-C


prCEN/TS 15410 - prCEN/TS 15411 Method D - EN 13657 (aqua regia, heating)


Test portion effect is generally not evident in recovery of major and trace elements. RSD values in general are about 4% for QR-E.


Higher values of RSD for minor elements (approximately 20%) were explained by their lower concentrations.

Effect of grain size (QR-E – paper plastic fluff)

Effect of amount of test portion (QR-E – paper plastic fluff)

No significant differences are observed in the average values of samples QR-E at different grain size levels, RSD average value is 3 %.

QR-E (paper- plastic fluff) EN 13657 variable:grain size

0

0.2

0.4

0.6

0.8

1

Al Ca/10 Fe K Mg Na P Si Ti

%

QR-E 0.5mmQR-E 1mmQR-E 1.5mm

QR-E (paper- plastic fluff) EN 13657 variable:amount of test portion

0

0.2

0.4

0.6

0.8

1

Al Ca/10 Fe K Mg Na P Si Ti

%

QR-E 0.1gQR-E 0.2gQR-E 0.4g


prCEN/TS 15410 - prCEN/TS 15411 Method D - EN 13657 (aqua regia, heating)

Method D results to be applicable for each kind of matrix tested; higher values of RSD are explained by intrinsic heterogeneity of samples.


EN 13657

variable: composition

0

510

15

20

2530

35

40


RS

D %

QR-E QR-A

QR-B QR-C

• Samples: QR-A (shredded tyre), QR-B (demolition wood), QR-C (dried sludge) and QR-E (paper-plastic fluff)

• Test portion: 0.2 g • Grain size: 1 mm, except QR-C sludge (finer).



Method D - EN 13657 (aqua regia,heating)


Ratio of recovery between EN 13657 and EN 13656 (aqua regia vs “total” HF)

Recovery rate isn’t significantly different between the two digestion procedures for almost all elements, except for Si, Ti and Sb (and Al in sewage sludge QR-C only).

Note: recovery of Si with EN 13656 is not guaranteed because of volatility of SiF4.

Ratio mean conc- EN 13657 / EN 13656

0

0.2

0.40.6

0.8

1

1.21.4

1.6

1.8


QR-A

QR-B

QR-C

QR-E

ratio mean conc EN13657 / EN 13656

00.20.40.60.8

11.21.41.61.8

Cr As Sb Pb Ba Co Cu Mn Mo Ni V Zn

QR-A

QR-B

QR-C

QR-E


prCEN/TS 15410 - prCEN/TS 15411 Method B - Ashing (prCEN/TS 15403) + EN 13656 (HF, HNO3, HCl)

0

0.1

0.2

0.3

0.4

0.5

Al Ca K Mg Na P Ti

con

c %

QR-A 0.5mm

QR-A 1mm

QR-A 1.5mm

0

5

10

15

20

25

Si Fe

con

c %

0

20

40

60

80

100

Cr As Cd Sb Pb Ba Ni Zn

mg

/kg

QR-A 05

QR-A 1

QR-A 15

0

200

400

600

800

1000

1200

Co Cu Mn

mg

/kg

Significant, not dramatic, influence of grain size for many elements (Fe, Ca, Al, K, Mg, P and minor elements). This behaviour was expected for this kind of matrix (oxides, refractory).

Note: recovery of Si with EN 13656 is not guaranteed because of volatility of SiF4

Effect of grain size (QR-A – shredded tires) Activity performed at ENEL


prCEN/TS 15410 Method B - Ashing (prCEN/TS 15403) + ASTM D4326 (XRF)

Activity performed at CESI – APAT – ENEL

Sample E - ash plastic-paper fluff bott 1

0

5

10

15

20

25

30

35

Na Mg Al Si S K Ca Ti Cr Mn Fe Co Ni Cu Zn As Se Sr Ba Pb V Sb Sn Tl P

RSD

(%

)

lab 1lab 2lab 3

Grinded ash shows generally lower RSD%.

The average concentration values for the major and minor elements are similar for grinded and non grinded ash, thus showing that the ash is sufficiently fine to be analysed as such by XRF.

Differences are observed between XRF results from the three labs even if calibrants and samples were prepared in same lab; this might be due to the different technologies of the instruments used. Furthermore, it appears that there is no “best” XRF technology for this kind of application.

ED-XRFLab 3

EDP-XRFLab 2

WD-XRFLab 1

Sample E - grinded ash plastic-paper fluff bott 1

0

5

10

15

20

25

30

35

Na Mg Al Si S K Ca Ti Cr Mn Fe Co Ni Cu Zn As Se Sr Ba Pb V Sb Sn Tl P

RSD

(%

)

lab 1lab 2lab 3


prCEN/TS 15410 - prCEN/TS 15411 Method C (perchloric acid at 190 °C)

The results obtained in this work show that:• 10 hours heating time is generally sufficient for major and minor element

recovery from paper/plastic SRF sample; but for some elements (Ti, Ba, Ca, Mg, K, Al) this is not true, a longer digestion time is required; Mg, Ba, Ca, Ti and P show also a significant interbottle difference

• It seems that generally RSD values are better at 0.5 mm in comparison to 1 mm grain size, but this is not so evident

• Differences are observed for the average values at 0.5 and 1 mm grain size: these differences are larger at 10 hours heating time, while the results are more similar at 20 hours time of heating

• This method requires the use of suitable closed bombs in order to stand the high pressure during digestion due to CO2 generation and to liquid vapour pressure of the acid mixture upon heating up to 190 °C. Not all the types of teflon bombs can be used, as clearly demonstrated in this work: stainless steel bombs are seldom used in the laboratories, because of the replacement with microwave digestion systems.

Activity performed at VTT/ CESI


prCEN/TS 15411Hg by direct method

(AMA – thermal decomposition, spectrometric determination of Hg vapors)

•Influence of test portion: 50, 75, 100 mg (QR-B – demolition wood, QR-E – paper-plastic fluff)•Influence of grain size: 0.5, 1, 1.5 mm (QR-E – paper plastic fluff)

.

QR-E - effect of amount of test portion

0

10

20

30

40

50

60

70

50 mg 75 mg 100 mg

µg

/kg

QR-E - effect of grain size

0

10

20

30

40

50

60

70

0.5mm 1mm 1.5mm

µg/k

g

No significant difference are observed in the average values of paper plastic samples at different test portion and grain size levels too; the RSD values are good (between 4 and 11%).

Demolition woos samples (QR-B) showed RSD values between 13 and 34%; higher RSD values were related to heterogeneity of the sample itself; no influence by amount of test portion

in this case as well.

Tests performed at APAT


prCEN/TS 15410 Methods for the determination of the content of major elements

(Al, Ca, Fe, K, Mg, Na, P, Si, Ti)



1 Scope

Te In addition to the digestionprocedure already included inthe TS, one more validatedstandard for waste samples isavailable (EN 13657). Thisstandard implies the use ofaqua regia only and for mostelements has quitecomparable performance toEN 13656 (hydrofluoric acid +aqua regia). Let the user thepossibility to avoid the use ofHF will make the procedure abit safer and less problematicfor instrumentation anddevices.

In the first paragraph change “three methods”into “four methods”.Add point d):d) microwave assisted digestion with nitric andhydrochloric acid mixture (aqua regia)In the fifth paragraph change the first sentencefrom “Method a) is recommended…” into“Methods a) and d) are recommended…”At the end of fifth paragraph add: “method d) isnot suitable for determination of Si and Ti because of poor recovery”.Last sentence should be modified as follows:All the listed methods but d) are suitable for thedetermination of Si, provided that closed containers are used for sample dissolution.XRF is highly recommended for Si, P and Tianalysis.

2NormativeReferences

Te Same as above Add:EN 13657 "Characterization of waste –Digestion for subsequent determination of aquaregia soluble portion of elements"


prCEN/TS 15410 Methods for the determination of the content of major elements

(Al, Ca, Fe, K, Mg, Na, P, Si, Ti)



9.1 Method A

Te Dissolution with HF mightproduce SiF4 (volatile) so a warning must be issued

At the end of 9.1 add a note like: Digestion withHF might produce SiF4 that is a volatilecompound, so if determination of Si is needed,special care has to be taken in this sense.

9.4 Method D(new)


Add:Weigh between 0,2 g to 0,5 g of the sample, tothe nearest 0,1 mg, prepared according to Clause 8 and transfer it into the vessel. Ifnecessary the sample may be moistened with aminimum amount of water. Proceed according to the general principle of EN 13657.After cooling the solutions are transferred tovolumetric flasks of suitable volume (e.g. 50ml).Any residue shall be separated by filtration or centrifugation and the composition is controlledby XRF: if a significant amount of the elements of interest is detected, an alternative digestion method for the dissolution of theresidual material is necessary.

10.3 Note 3

Te Influence by particle size isnot dramatic

Delete word “strongly”


prCEN/TS 15411 Methods for the determination of the content of trace elements

(As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Tl, V and Zn)



1 Scope


In the first paragraph change “three methods”into “four methods”.Add point d):d) microwave assisted digestion with nitric andhydrochloric acid mixture (aqua regia)In the fourth paragraph change the firstsentence from “Method a) is recommended…”into “Methods a) and d) are recommended…”At the end of fifth paragraph add: “method d) isnot suitable for determination of Sb because ofpoor recovery”.

2NormativeReferences

Te Same as above Add:EN 13657 "Characterization of waste – Digestionfor subsequent determination of aqua regiasoluble portion of elements"

5 Principle

Te A reference to the directdetermination of Hg is missing

Add at the end of sentence: “or, when available,dedicated specific methods (Hg)”.


prCEN/TS 15411 Methods for the determination of the content of trace elements

(As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Tl, V and Zn)



9.2 Method B

Te Ashing can lead to loss ofvolatile elements

Add at the end of 9.2 a note like: “hightemperature (550 °C) reached during ashing canlead to loss of volatile elements”.

9.4 Method D(new)

Te Same as comment for point 1(Scope)

Add:Weigh between 0,2 g to 0,5 g of the sample, tothe nearest 0,1 mg, prepared according to Clause 8 and transfer it into the vessel. Ifnecessary the sample may be moistened with aminimum amount of water. Proceed according tothe general principle of EN 13657.After cooling the solutions are transferred tovolumetric flasks of suitable volume (e.g. 50 ml). Any residue shall be separated by filtration or centrifugation and the composition is controlledby XRF: if a significant amount of the elements of interested is detected, an alternative digestion method for the dissolution of the residualmaterial is necessary.


Activity performed at VTT

33grain sizeMethod B - ashing + DTA

3grain size

3amount of test portion

73boiling timeMethod A – Leaching with HNO3, filtering, alkaline digestion of residue, determination of Al by ICP-OES or FAAS.

Total levels

NotesNo of levels

Key variablesMethod

prCEN/TS 15412 Methods for the determination of metallic aluminium


prCEN/TS 15412 Methods for the determination of metallic aluminium (method A)

Leaching with HNO3, filtering, alkaline digestion of residue, determination of Al by ICP-OES or FAAS.

• Metallic particles are heterogeneously distributed in the sample large test portions are to be used (i.e. up to 5 g test portion if metallic aluminium is not visible in the sample).

• Due to high particle density variation in samples and test portions attention should be paid on possible segregation of particle during transportation, handling and even when removing a test portion from laboratory sample.

• Recovery rate can be checked by spiking with metallic aluminium.


prCEN/TS 15412 Method for the determination of metallic aluminium (method B – ashing + DTA)

0,000

0,500

1,000

1,500

2,000

2,500

w-% w-%

Ash 800 °C Ash 550 °C

w %

QR-E, 0.5 mm

QR-E, 1.0 mm

QR-E, 1.5 mm

The main interference in the measurement was found to be is calcite in the samples.

If calcite content and aluminium content on the sample are high or low, the determination of metallic aluminium goes without problems. If the concentration of another component is high and the concentration of the other component is low, it seems better to make ashes at 815 ºC and aluminium content is determined immediately.

Ashing of samples was made at 550 C and 800 C, because calcium carbonate doesn’t degrade at 550°C.

Sample: paper plastic fluff (QR-E)


prCEN/TS 15412 Methods for the determination of metallic aluminium



9.2Samplepreparation

Te Homogeneity for thisparameter is critical

Add: “It is recommended that laboratorysamples are homogenised properly before extracting of test portion. This may be doneusing so called long pile technique.”

11Qualitycontrol

Te For this parameter arecovery control is possible

Add: “Recovery rate of the test method ischecked using spiked samples, e.g. virgin woody material mixed with known amount ofmetallic aluminium (of different filmthicknesses).”


Some of main results that led to proposals of amendments for methods are listed below:

• Robustness study shows that the method prCEN/TS 15408 (determination of S, Fl, Cl and Br) is not applicable in its current form to some samples (e.g. containing tyre pieces) because the prepared pellet tend to break during combustion. To overcome this limitation, some amendments to the method have been proposed to CEN TC 343.

• Method D (digestion with only aqua regia) proposed in addition to the digestion procedure already included in the TS 15410 and 15411, has quite comparable performance to Method A (EN 13656: hydrofluoric acid + aqua regia) for most elements (except for Si, Ti, Sb).

All amendments have been discussed and approved by WG5 of TC/343

QUOVADIS workshop, October 24, 2007 1 QUOVADIS Project Quality Management Organisation, Validation...

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