1、BS 2975-2:2008Sampling and analysis of glass-making sands Part 2: Methods for chemical analysis ICS 81.040.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when th
2、e document was last issued. BSI 2008ISBN 978 0 580 58104 5The following BSI references relate to the work on this standard:Committee reference LBI/36Draft for comment 08/30159621 DCPublication historyFirst published as BS 2975 March 1958Second edition as BS 2975, February 1988First published as Part
3、 2 August 2008Amendments issued since publicationAmd. no. Date Text affectedBS 2975-2:2008 BSI 2008 iBS 2975-2:2008ContentsForeword ii1 Scope 12 Normative references 13 Type of material 14 Sample preparation 25 Loss on ignition (LOI) 46 X-ray fluorescence (XRF) 57 Wet chemistry 88 Combustion 21Annex
4、esAnnex A (informative) Guidance on using the XRF pressed powder method (see 6.3) 22Annex B (informative) Compositions of sand CRMs 23Bibliography 24List of tablesTable 1 Calibration ranges and methods 1Table 2 Suitable grinding media for silica sands 3Table B.1 Composition of sand CRMs 23Summary of
5、 pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 24, an inside back cover and a back cover.BS 2975-2:2008ii BSI 2008ForewordPublishing informationThis part of BS 2975 is published by BSI and came into effect on 29 August 2008. It was prepared by Technica
6、l Committee LBI/36, Laboratory glassware and related apparatus. A list of organizations represented on this committee can be obtained on request to its secretary.SupersessionThis part of BS 2975, along with BS 2975-1:2004, supersedes BS 2975:1988, which is withdrawn.Relationship with other publicati
7、onsBS 2975 is published in two parts, as follows:Part 1: Methods for sampling and physical testing of glass-making sands;Part 2: Methods for chemical analysis.Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Its methods are expressed as a set of i
8、nstructions, a description, or in sentences in which the principal auxiliary verb is “shall”.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standa
9、rd cannot confer immunity from legal obligations. BSI 2008 1BS 2975-2:20081 Scope This British Standard describes methods suitable for the chemical analysis of glass-making sands, including instrumental methods using X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission
10、spectrometry (ICP-OES), ultraviolet-visible spectrometry (UV-VIS) and atomic absorption spectrometry (AAS).2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, t
11、he latest edition of the referenced document (including any amendments) applies. BS 2975-1, Sampling and analysis of glass-making sands Part 1: Methods for sampling and physical testing of glass-making sandsBS EN ISO 12677:2003, Chemical analysis of refractory products by XRF Fused cast bead method3
12、Type of material The calibration ranges and methods to be used for the chemical analysis of glass-making sands shall be as set out in Table 1.Table 1 Calibration ranges and methods Oxide Method Range % m/mMin MaxLOI Gravimetric 0.10 1.0Fe2O3XRF / UV-VIS / ICP-OES 0.005 1.0Al2O3XRF / ICP-OES / AAS 0.
13、04 5.0Cr2O3ICP-OES / AAS 0.000 1 0.03K2O XRF / Flame Photometer / AAS 0.01 3.0SiO2XRF / Gravimetric 94.0 99.8TiO2XRF / UV-VIS 0.016 0.10CaO XRF / AAS / Titration 0.006 1.0MgO XRF /AAS 0.002 1.0Mn3O4XRF / AAS 0.0 0.03S= XRF / ICP-OES / Combustion 0.0 0.05Ni ICP-OES 0.0 0.000 6Co ICP-OES 0.0 0.000 1Cu
14、 ICP-OES 0.0 0.000 35Na2O XRF / AAS / ICP-OES / Flame Photometer 0.05 2.0 Pb3O4XRF 0.0 0.000 5Carbon Combustion 0.0 0.1NOTE The analytes are expressed in the stable oxidation state; correction should be made if other oxidation states are needed.BS 2975-2:20082 BSI 20084 Sample preparation 4.1 Genera
15、lControl (extraction) systems shall be put in place to reduce exposure to respirable crystalline silica dust to the lowest practicable level.The specimen or solution to be presented to the instrument shall be prepared from a dry homogeneous finely powdered sample (the procedure for drying silica san
16、d is given in 4.3.3).Appropriate bulk sampling methods shall be used to produce a laboratory sample as set out in BS 2975-1. The particle size of the laboratory sample shall be reduced for both wet chemical and XRF techniques.The accuracy of XRF methods for pressed powder samples is highly dependent
17、 on the particle size distribution of the sample; the particle size of material to be used for the preparation of pressed powders shall be less than 75 4m.NOTE 1 Particle size reduction can be carried out by grinding in a suitable mechanical device or by hand using appropriate grinding media.NOTE 2
18、Consistent grain size may be difficult to obtain if the sample is ground by hand. Commercially available mechanical mills for particle size reduction on a laboratory scale include: ball mills, either planetary or centrifugal (3 axes); disc mills, also called swing mills, ring-and-puck mills or shatt
19、erboxes (2 axes); mortar mills (essentially mechanized pestle-and-mortars).The potential for contamination of the sample with elements that are to be determined should be considered when grinding media are chosen. For this reason carbon steel, chrome steel, and zirconia media are not recommended. Su
20、itable media are shown in Table 2.4.2 Apparatus4.2.1 Drying vessel.4.2.2 Drying oven to 110 C 10 C.4.2.3 Riffle box.4.2.4 Balance, capable of weighing to 0.01 g.4.2.5 Timer.4.2.6 Extraction system.4.2.7 Pestle and mortar or mechanical mill, type dependent on sample size and intended analysis (see Ta
21、ble 2).4.2.8 Desiccator containing dry desiccant.4.2.9 Fine brush. BSI 2008 3BS 2975-2:20084.3 ProcedureNOTE This procedure should be carried out with appropriate extraction (4.2.6) control measures to reduce exposure to respirable crystalline silica dust.4.3.1 Select grinding medium, based on sampl
22、e size, sample hardness and chemical analysis to be performed (see Table 2). Very small samples can be ground by hand using agate or porcelain pestle and mortar (4.2.7). To minimize particle size effects, prepare the sand by grinding to ensure that the fineness is to the tolerance of 10% maximum ret
23、ained at 75 4m and 0% retained at 150 4m.4.3.2 If the sample is dry proceed to 4.3.5. If the sample is moist, use a cone and quartering technique to obtain sufficient sample for the capacity of the grinding vessel to be used. 4.3.3 Dry the moist sand for 1 h or to constant mass in a suitable drying
24、vessel (4.2.1) in an oven at 110 C 10 C (4.2.2).4.3.4 Remove from the oven (4.2.2) and cool in a desiccator containing dry desiccant (4.2.8).4.3.5 Riffle dry sample in a riffle box (4.2.3). 4.3.6 Clean the mill (4.2.7), finishing the process with one of the cleaning agents recommended in A.12.4.3.7
25、Weigh on a balance (4.2.4) the recommended amount of sample for the chosen milling vessel.4.3.8 Place weighed sample into the mill (4.2.7), transfer into the mechanical device and grind for the required time using a timer (4.2.5) if one is not fitted to the device.4.3.9 Empty the mill (4.2.7), under
26、 extraction (4.2.6), onto a clean surface removing as much of the sample as possible using a fine brush (4.2.9).NOTE An appropriate sized sieve and receiver can be used for ease of separating and cleaning spherical grinding media.Table 2 Suitable grinding media for silica sandsRecommended mediaRecom
27、mended use Typical analysis Possible contaminationNotesTungsten carbide (normally cemented with Co, but Fe, etc., may be used)XRF fused cast bead WC 94%, Co 6% W, Co or other cementation elements, e.g. NiCheck specification with supplierAgate All XRF techniques, wet chemistrySiO299.9% Insignificant
28、Use with a slow mill speedSyalon (silicon nitride, silicon aluminium oxynitride)All XRF techniques, wet chemistrySi 53.5%, N 35.2%, O 4.8%, Y (or Er) 3.5%, Al 2.5%, Mg 0.5%Al, Y (or Er) Can be brittleHard porcelain All XRF techniques, wet chemistryAl2O340%, SiO260% Al Used in mortar millsNOTE Sample
29、s may be hand ground in any of the above media, to an appropriate particle size. Sample loss should be avoided. Consideration should be given to manufacturers recommendations regarding appropriate sample size and milling time.BS 2975-2:20084 BSI 20084.3.10 Place the ground sample into a clean recept
30、acle or self seal plastic bag and label it appropriately.4.3.11 Clean the mill (4.2.7) and the brush (4.2.9).4.4 Validation of grain sizeContamination of the sample by the grinding media shall be quantified in accordance with Table 2. The grinding performance of the mill shall be monitored to ensure
31、 the required fineness of the material is achieved. To combat wear caused to the grinding media over time, which can impact on the grain size of the product, pucks, rings and spheres shall be checked, and pots shall be relined as necessary to maintain particle size distribution. When using spheres,
32、the number and mass per grinding pot shall be kept constant. 5 Loss on ignition (LOI)COMMENTARY ON CLAUSE 5 LOI is the weight change, expressed as a percentage, caused by heating the sample to a high temperature. It is used to give a measure of the extent of substances that are volatile below the gi
33、ven temperature.For further details on LOI methodology, see BS EN ISO 21587-1.5.1 Apparatus 5.1.1 Platinum boat, or other suitable vessel of sufficient size to contain 2 g of sample at 1 050 C.5.1.2 Balance, capable of weighing to 0.000 1 g.5.1.3 Desiccator containing dry desiccant, e.g. silica gel.
34、5.1.4 Furnace held at 1 050 C 50 C.5.1.5 Long handled tongs.5.1.6 Spatula.5.1.7 Drying oven to 110 C 10 C.5.2 Procedure5.2.1 Dry not less than 10 g of the ground sample in an oven (5.1.7) at 110 C 10 C or to constant mass (7.8.1.18) in order to evaluate LOI.5.2.2 Store over a drying agent in a desic
35、cator (5.1.3) whilst cooling. 5.2.3 Weigh boat (5.1.1) and record weight W1.5.2.4 Using a balance (5.1.2) add 2 g 0.000 1 g of sample into the boat (5.1.1) and record the weight W2.5.2.5 Using the tongs (5.1.5) place boat (5.1.1) and sample in the furnace (5.1.4) set at 1 050 C for 60 minutes.5.2.6
36、Remove from furnace (5.1.4) with tongs (5.1.5) and place in a desiccator (5.1.3) to cool. BSI 2008 5BS 2975-2:20085.2.7 Once cool, re-weigh boat (5.1.1) and sample and record weight W3.Calculate the LOI (%) in accordance with the following equation:where:W1= weight of boat;W2= weight of boat and sam
37、ple;W3= weight of ignited boat and sample.6 X-ray fluorescence (XRF)6.1 GeneralThe intensities of the fluorescent X-rays from the elements of interest in the sample shall be measured and the chemical composition of the sample shall be analysed by reference to previously determined calibration graphs
38、 or equations, applying correction factors for inter-element effects.NOTE 1 The X-ray intensity might not be directly proportional to the concentration but modified by the concentration of other analytes in the sample (inter-element or matrix effects).Calibration equations and inter-element correcti
39、ons shall be established from specimens made from Certified Reference Materials (CRMs) and, where appropriate, synthetic calibrating materials prepared in the same way as the unknowns. Homogeneity, particle size distribution, matrix effects, instrument drift and accuracy of relevant calibration line
40、s shall therefore be taken in to account during specimen measurement.NOTE 2 Specimens can be prepared for analysis as:a) fused cast beads;b) pressed powder pellets;c) loose powders.NOTE 3 The use of fused cast beads offers the following advantages and disadvantages:a) mineralogical and particulate e
41、ffects are removed;b) calibration can include beads prepared from mixtures of pure oxides or carbonates in addition to CRMs;c) dilution with borate flux might significantly affect the sensitivity of analytes present at “trace” level.NOTE 4 Pressed powder calibration standards should be the same type
42、 of matrix as the unknown samples (e.g. same mineralogy). In most cases the mineralogical composition of available reference materials is unknown. Calibration with such materials using pressed pellets is subject to uncertainty.NOTE 5 The XRF spectrometer software can support a number of models for l
43、ine overlap and matrix corrections to determine coefficients that describe the shape of the calibration curve. Instrument specific drift correction should be applied if the calibration falls outside acceptable limit values.LOIW2W3W2W1- 100=BS 2975-2:20086 BSI 20086.2 XRF fused cast bead XRF cast bea
44、ds shall be generated in accordance with BS EN ISO 12677.6.3 XRF pressed powder pellet COMMENTARY ON 6.3 Powder calibrations for pressed pellet are specific to the mineralogical and particulate matrix for which they are developed. For example, materials with different particle shapes or different de
45、grees of crystallinity might need separate calibrations. CRMs might not be available in the same matrix as the unknowns.Guidance on using the XRF pressed pellet method is given in Annex A.6.3.1 Apparatus 6.3.1.1 Balance, capable of weighing to 0.01 g.6.3.1.2 Grinding equipment.6.3.1.3 Weighing vesse
46、l.6.3.1.4 40 mm stainless steel die set (two pellet dies, holder and plunger).6.3.1.5 Reinforcing metal cup (optional).6.3.1.6 Motorized press, capable of 25 t pressure.6.3.1.7 Tray.6.3.1.8 Oven maintained at 110 C 10 C.6.3.1.9 Desiccator containing dry desiccant, e.g. silica gel.6.3.2 Reagents6.3.2
47、.1 Binder (optional).6.3.2.2 Suitable solvent, e.g. acetone or ethanol (or industrial methylated spirits).6.3.3 Procedure6.3.3.1 Weigh the ground sample into a weighing vessel (6.3.1.3).6.3.3.2 Add binder (6.3.2.1) if appropriate.6.3.3.3 Clean the grinding equipment (6.3.1.2) with a suitable solvent
48、 (6.3.2.2).6.3.3.4 Place the sample into the cleaned grinding vessel (6.3.1.2) and mill thoroughly.6.3.3.5 Transfer mixed sample to the die (6.3.1.4), previously cleaned with a suitable solvent (6.3.2.2) and with a reinforcing metal cup (6.3.1.5) placed in the base.6.3.3.6 Ensure that the surface of
49、 the sample in the die (6.3.1.4) is level.6.3.3.7 Insert the die plunger (6.3.1.4) and motorized press (6.3.1.6), typically at 20 t pressure for 20 s, however, this is dependent on the sand mineralogy. BSI 2008 7BS 2975-2:20086.3.3.8 Release pressure and extract the pellet carefully. It is important that the resulting pellet is flat and uniform on the analytical surface.6.3.3.9 If a binder (6.3.2.1) has been used and needs to be cured, place on a tray (6.3.1.7) in an oven (6.3.1.8)
