1、BSI Standards Publication PD ISO/TS 16996:2015 Solid biofuels Determination of elemental composition by X- ray fluorescencePD ISO/TS 16996:2015 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of ISO/TS 16996:2015. The UK participation in its preparation was entr
2、usted to Technical Committee PTI/17, Solid biofuels. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The Brit
3、ish Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 81943 8 ICS 27.190; 75.160.10 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standards Policy and Strategy Commit
4、tee on 31 December 2015. Amendments issued since publication Date Text affectedPD ISO/TS 16996:2015 ISO 2015 Solid biofuels Determination of elemental composition by X-ray fluor esc enc e Biocarburants solides Dtermination de la composition lmentaire par fluorescence de rayons X TECHNICAL SPECIFICAT
5、ION ISO/TS 16996 Reference number ISO/TS 16996:2015(E) First edition 2015-12-01PD ISO/TS 16996:2015ISO/TS 16996:2015(E)ii ISO 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be r
6、eproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the reque
7、ster. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgPD ISO/TS 16996:2015ISO/TS 16996:2015(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Saf
8、ety remarks 2 5 Symbols and abbreviated terms . 3 5.1 Symbols . 3 5.2 Abbreviated terms . 3 6 Principle 3 7 Apparatus . 4 8 Interferences and sources of error 4 9 Sample preparation . 5 9.1 Preparation principles 5 9.2 Drying of general analysis sample material . 5 9.3 Preparation of pressed pellet
9、. 5 10 Procedure. 5 10.1 Analytical measurement conditions . 5 10.1.1 Wavelength dispersive instruments . 5 10.1.2 Energy dispersive instruments . 6 10.2 Calibration 7 10.2.1 General 7 10.2.2 General calibration procedure . 8 10.2.3 Calibration procedure using the pressed pellet method (recommended
10、method) 8 10.3 Procedures for correcting matrix effect 9 10.3.1 Internal standard correction using Compton (incoherent) scattering method 9 10.3.2 Fundamental parameter approach 9 10.3.3 Fundamental or theoretical influence coefficient method 9 10.3.4 Empirical alpha correction .10 10.4 Analysis of
11、the samples .11 11 Quality control .11 11.1 Drift correction procedure .11 11.2 Reference materials .11 12 Calculation of the result .11 13 Performance characteristics .12 14 Test report 12 Annex A (informative) Publicly available biomass reference materials 13 Bibliography .14 ISO 2015 All rights r
12、eserved iii Contents PagePD ISO/TS 16996:2015ISO/TS 16996:2015(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical
13、committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with
14、the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed fo
15、r the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent right
16、s. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this
17、 document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to
18、 Trade (TBT) see the following URL: Foreword - Supplementary information. The committee responsible for this document is ISO/TC 238, Solid biofuels.iv ISO 2015 All rights reservedPD ISO/TS 16996:2015ISO/TS 16996:2015(E) Introduction X-ray fluorescence spectrometry can be used as a fast method for a
19、qualitative overview of ash forming elements and impurities. When calibration is based on biomass reference materials, X-ray fluorescence spectrometry can be used for a quantitative analysis of the total content of the specified elements within different solid biofuels. The quality of the results ob
20、tained depends very closely on the type of instrument used, e.g. bench top or high performance, energy dispersive or wavelength dispersive instruments. When selecting a specific instrument, several factors have to be considered, such as the matrices to be analysed, elements to be determined, detecti
21、on limits required and the measuring time. Due to the wide range of matrix compositions and the lack of suitable reference materials in the case of some biomass like olive residues, it is generally difficult to set up a calibration with matrix-matched reference materials. Therefore, this Technical S
22、pecification describes two different procedures. Quantitative analytical procedure for major elements of biomass. The calibration is based on different biomass reference materials. The elements described as major elements of solid biofuels are in fact major elements of the fuel ashes more than of th
23、e fuels. The determination of these elements may be helpful to predict the melting behaviour and slagging of the ashes. Moreover, contamination of fuel with sand or soil is indicated by high values of several elements. Total element characterization at a semi-quantitative level for major elements of
24、 biomass. The calibration is based on matrix-independent calibration curves, previously set up by the manufacturer. In general, the sensitivity of X-ray fluorescence is not sufficient for a determination of the content of minor elements (trace metals) in solid biofuels. However, determination may be
25、 used to reveal excessive contents of minor elements in solid biofuels. ISO 2015 All rights reserved vPD ISO/TS 16996:2015PD ISO/TS 16996:2015Solid biofuels Determination of elemental composition b y X -r a y fluor esc enc e 1 Scope This Technical Specification specifies the procedure for a determin
26、ation of major and minor element concentrations in biomass material by energy dispersive X-ray fluorescence (EDXRF) spectrometry or wavelength dispersive X-ray fluorescence (WDXRF) spectrometry using a calibration with biomass reference materials. A semi-quantitative determination may be carried out
27、 using matrix independent standards. This Technical Specification is applicable for the following elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Mo, Cd, Sb, and Pb. Concentrations from approximately 0,000 1 % and above can be determined depending on the element
28、, the calibration materials used and the instrument used. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the late
29、st edition of the referenced document (including any amendments) applies. ISO 16559, Solid biofuels Terminology, definitions and descriptions 3 T erms a nd definiti ons For the purposes of this document, the terms and definitions given in ISO 16559 and the following apply. 3.1 absorption edge abrupt
30、 change in mass absorption coefficient at a specific wavelength or energy 3.2 absorption of X-rays loss of intensity of X-rays through absorption by an isotropic and homogenous material as described by the Beer-Lambert law 3.3 analytical line specific characteristic X-ray spectral line of the atom o
31、r ion of the analyte used for determination of the analyte content 3.4 continuous radiation electromagnetic radiation produced by the acceleration of a charged particle, such as an electron, when deflected by another charged particle, such as an atomic nucleus 3.5 compton-line spectral line due to i
32、ncoherent scattering (Compton-effect), occurring when the incident X-ray photon strikes an atom without promoting fluorescence Note 1 to entry: Energy is lost in the collision and therefore, the resulting scattered X-ray photon is of lower energy than the incident X-ray photon. TECHNICAL SPECIFICATI
33、ON ISO/TS 16996:2015(E) ISO 2015 All rights reserved 1PD ISO/TS 16996:2015ISO/TS 16996:2015(E) 3.6 drift correction monitors physically stable samples used to correct for instrumental drift 3.7 emitted sample X-rays radiation emitted by sample consisting of X-ray fluorescence radiation (3.14) and sc
34、attered primary X-rays (3.12) 3.8 m a s s a b s o r p t i o n c o e f f i c i e n t constant describing the fractional decrease in the intensity of a beam of X-radiation as it passes through an absorbing medium Note 1 to entry: It is expressed in cm 2 /g. Note 2 to entry: The mass absorption coeffic
35、ient is a function of the wavelength of the absorbed radiation and the atomic number of the absorbing element. 3.9 polarised excitation X-ray spectrometer energy dispersive X-ray spectrometer where the excitation is performed by polarised radiation and the emitted X-ray fluorescence radiation (3.14)
36、 is detected along the direction of polarisation 3.10 powder sample analyte sample submitted as a powder for direct measurement in the sample cup 3.11 pressed pellet analyte sample prepared by pressing milled material into a disk 3.12 primary X-rays X-rays by which the sample is radiated 3.13 qualit
37、y control sample stable sample with known contents, e.g. certified reference material (CRM) used to monitor instrument and calibration performance 3.14 X - r a y f l u o r e s c e n c e r a d i a t i o n emission of characteristic X-rays from a sample that has been bombarded by high-energy X-rays or
38、 gamma rays 4 Safety remarks The X-ray fluorescence spectrometer shall comply with international and national regulations relevant to radiation protection. The person responsible for managing or supervising the operation of X-ray equipment shall provide evidence of his knowledge of radiation protect
39、ion according to national regulations.2 ISO 2015 All rights reservedPD ISO/TS 16996:2015ISO/TS 16996:2015(E) 5 Symbols and abbreviated terms 5.1 Symbols Al Aluminium As Arsenic Ca Calcium Cd Cadmium Co Cobalt Cr Chromium Cu Copper Fe Iron K Potassium Mg Magnesium Mn Manganese Mo Molybdenum Na Sodium
40、 Ni Nickel P Phosphorus Pb Lead Sb Antimony Ti Titanium V Vanadium Zn Zinc 5.2 Abbreviated terms EDXRF Energy dispersive X-ray fluorescence MCA Multi-Channel Analyser WDXRF Wavelength dispersive X-ray fluorescence 6 Principle After a suitable preparation, the sample is introduced into a XRF-spectrom
41、eter and excited by primary X-rays. The intensities of the secondary fluorescent energy lines specific for each element are measured and the elemental composition of the sample is determined by reference to previously established calibration graphs or equations and applying corrections for inter-ele
42、ment effects. The calibration equations and inter-element corrections are established using pure reagents and/or series of internal or reference materials provided that they meet all the requirements of the relevant preparation technique. ISO 2015 All rights reserved 3PD ISO/TS 16996:2015ISO/TS 1699
43、6:2015(E) 7 Apparatus 7.1 X -r a y fluor esc enc e spectr omet er, shall be able to analyse the elements according to the scope of this Technical Specification. The following types of X-ray fluorescence spectrometers are applicable: energy dispersive X-ray fluorescence (EDXRF) spectrometer that achi
44、eves the dispersion of the emitted X-ray fluorescence radiation by an energy dispersive detector; wavelength dispersive X-ray fluorescence (WDXRF) spectrometer that achieves the dispersion of the emitted X-ray fluorescence radiation by diffraction by a crystal or a synthetic multilayer. The spectrom
45、eter consists of the following components: primary X-ray source, an X-ray tube with a high voltage generator; sample holder; detector unit including electronic equipment; source modifiers to modify the shape or intensity of the source spectrum or the beam shape (like source filters, secondary target
46、s, polarizing targets, collimators, focusing optics, etc.). The detector unit is different for WDXRF and for EDXRF spectrometers. WDXRF spectrometers take advantage of the dispersion of the emitted radiation by diffraction by a crystal or a synthetic multilayer. The detector does not need to be capa
47、ble of energy discrimination. EDXRF spectrometers use an energy dispersive detector. Pulses of current from the detector, which are a measure of the energy of the incoming X-rays, are segregated into channels according to energy using a Multi-Channel Analyser (MCA). NOTE 1 The use of a high-energy X
48、-ray tube increases the potential for losses of volatile analytes from samples by heating in the spectrometer during analysis. NOTE 2 The new generation of EDXRF spectrometers takes advantage of the polarizing target theory resulting in a significant decrease of the background scattering, and theref
49、ore lower limits of detection can be achieved (comparable to WDXRF). 7.2 Pellet press, capable of providing a pressure of at least 50 kN. The pellet press may be a cold press, operating at temperatures not exceeding 150 C. 8 Interferences and sources of error Interferences in X-ray fluorescence spectrometry are due to spectral line overlaps, matrix effects, spectral artefacts and particle size or mineralogical effects. Spectral line overlaps occur when an analytical line cannot be resolved from the line of a different element.
