1、 Reference number ISO 14435:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 14435 First edition 2005-07-15 Carbonaceous materials for the production of aluminium Petroleum coke Determination of trace metals by inductively coupled plasma atomic emission spectrometry Produits carbons pour la production de
2、laluminium Coke de ptrole Dtermination des mtaux ltat de trace par spectromtrie dmission atomique avec plasma induit par haute frquence ISO 14435:2005(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but sh
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7、 Web www.iso.org Published in Switzerland ii ISO 2005 All rights reservedISO 14435:2005(E) ISO 2005 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope. 1 2 Normative references. 1 3 Terms and definitions. 1 4 Principle. 2 5 Interferences. 2 6 Apparatus 3 7 Reagents 4 8 Sample p
8、reparation 5 9 Preparation of apparatus . 5 10 Procedure 6 11 Calculation. 7 12 Test report. 7 13 Precision and bias for the dried test portion . 8 Bibliography . 9 ISO 14435:2005(E) iv ISO 2005 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide feder
9、ation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that commit
10、tee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordanc
11、e with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires a
12、pproval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14435 was prepared by Technical Com
13、mittee ISO/TC 226, Materials for the production of primary aluminium. ISO 14435:2005(E) ISO 2005 All rights reserved v Introduction The presence and concentration of various metallic elements in a petroleum coke are major factors in determining the suitability of the coke for various end-uses. Users
14、 of petroleum coke require a standard procedure to determine the concentrations of these metallic elements in a coke sample. This International Standard describes such a procedure. This International Standard is based on ASTM method D5600-98, published under the jurisdiction of ASTM Committee D2 on
15、Petroleum Products and Lubricants and Subcommittee DO2.05.01 on Petroleum Coke Sampling and Procedures. The repeatability and reproducibility information is based on an interlaboratory trial, which is reported in Research Report D02-1007 available from ASTM Headquarters. INTERNATIONAL STANDARD ISO 1
16、4435:2005(E) ISO 2005 All rights reserved 1 Carbonaceous materials for the production of aluminium Petroleum coke Determination of trace metals by inductively coupled plasma atomic emission spectrometry WARNING This International Standard does not purport to address all of the safety concerns, if an
17、y, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard applies to carbonaceous materials for the production of a
18、luminium. This International Standard describes a test method which covers the analysis for commonly determined trace metals in test specimens of raw and calcined petroleum coke by inductively coupled plasma atomic emission spectroscopy. It can also be applied to other heat-treated carbonaceous mate
19、rials e.g. coal-tar pitch coke, anthracite. Elements to which this test method applies are listed in Table 1. Detection limits, sensitivity, and optimum ranges of the metals will vary with the matrices and model of spectrometer. This test method is applicable only to samples containing less than a m
20、ass fraction of 1 % ash. Elements present at concentrations above the upper limit of the working ranges can be determined with additional, appropriate dilutions. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, on
21、ly the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6375, Carbonaceous materials for the production of aluminium Coke for electrodes Sampling ISO 3696:1987, Water for analytical laboratory use Specification and t
22、est methods ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 petroleum coke solid, carbonaceous residue produced by thermal decomposition of hea
23、vy petroleum fractions and cracked stocks ISO 14435:2005(E) 2 ISO 2005 All rights reserved3.2 coal-tar pitch coke solid, carbonaceous residue produced by decomposition of coal-tar pitch 3.3 gross sample original, uncrushed, representative portion taken from a shipment or lot of coke 4 Principle A te
24、st sample of the petroleum coke is ashed at 700 C. The ash is fused with lithium borate. The melt is dissolved in dilute nitric acid (HNO 3 ), and the resultant solution is analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES) using simultaneous, or sequential, multi-elementa
25、l determination of elements. The solution is introduced to the ICP instrument by free aspiration or by an optional peristaltic pump. The concentrations of the trace metals are then calculated by comparing the emission intensities from the sample with the emission intensities of the standards used in
26、 calibration. 5 Interferences For spectral interferences, follow the instrument manufacturers operating guide to develop and apply correction factors to compensate for the interferences. To apply interference corrections, all concentrations shall be within the previously established linear-response
27、range of each element. NOTE Spectral interferences are caused by a) overlap of a spectral line from another element, b) unresolved overlap of molecular band spectra, c) background contribution from continuous or recombination phenomena, and d) stray light from the line emission of high-concentration
28、 elements. Spectral overlap can be compensated for by computer-correcting the raw data after monitoring and measuring the interfering element. Unresolved overlap requires selection of an alternate wavelength. Background contribution and stray light can usually be compensated for by a background corr
29、ection adjacent to the analyte line. Physical interferences are effects associated with the sample nebulization and transport processes. Changes in viscosity and surface tension can cause significant inaccuracies, especially in samples containing high amounts of dissolved solids or high acid concent
30、rations. If physical interferences are present, they shall be reduced by diluting the sample, by using a peristaltic pump, or by using the standard-additions method. Another problem that can occur with high amounts of dissolved solids is build-up of salts at the tip of the nebulizer, which can affec
31、t aerosol flow rate and cause instrumental drift. This problem can be controlled by wetting the argon prior to nebulization by using a tip washer, or diluting the sample. ISO 14435:2005(E) ISO 2005 All rights reserved 3 Table 1 Elements determined and suggested wavelengths Wavelengths Concentration
32、range Element nm a,bg/g cAluminium 237,313 256,799 308,215 396,152 15 to 110 Barium 455,403 493,410 1 to 65 Calcium 317,933 393,367 396,847 10 to 140 Iron 259,940 40 to 700 Magnesium 279,079 279,553 5 to 50 Manganese 257,610 294,920 1 to 7 Nickel 231,604 341,476 352,454 3 to 220 Silicon 212,412 251,
33、611 288,159 60 to 290 Sodium 588,995 589,592 30 to 160 Titanium 334,941 337,280 1 to 7 Vanadium 292,402 2 to 480 Zinc 202,548 206,200 213,856 1 to 20 aThe wavelengths listed were utilized in the interlaboratory trial because of their sensitivity. Other wavelengths can be substituted if they can prov
34、ide the required sensitivity and are treated with the same corrective techniques for spectral Interference (see Clause 5). In time, other elements may be added as more information becomes available and as required. bAlternative wavelengths can be found in references such as Inductively Coupled Plasm
35、a Atomic Emission Spectroscopy, Winge, R.K., Fassel, V.A., Peterson, V.J., and Floyd, M.A., Elsevier, 1985. cBased on this interlaboratory trial. This method can be applicable to other elements or concentration ranges, but precision data are not available. 6 Apparatus 6.1 Balance, top loading, with
36、automatic tare, capable of weighing to 0,000 1 g, of capacity 150 g. 6.2 Ceramic cooling plate, desiccator plates have been found to be effective. 6.3 Crucible support, nichrome wire triangles. 6.4 Furnaces, electric, capable of temperature regulation at 700 C 10 C and 1 000 C 10 C, with allowances
37、for exchange of combustion gases and air. 6.5 Inductively coupled plasma atomic emission spectrometer, either a sequential or simultaneous spectrometer is suitable, equipped with a quartz ICP torch and radio frequency (RF) generator to form and sustain the plasma. 6.6 Magnetic stirring bars, polytet
38、rafluoroethylene (PTFE) coated, approximately 12 mm in length. 6.7 Magnetic stirring hotplate. 6.8 Meker-type forced air burner. 6.9 Nebulizer, a high-solids nebulizer is recommended. 6.10 Peristaltic pump, a peristaltic pump is recommended. ISO 14435:2005(E) 4 ISO 2005 All rights reserved6.11 Plati
39、num dish, of capacity 50 ml to 58 ml, recommended type Pt II (Pt containing 5 % mass fraction Au). 6.12 Platinum dish, of capacity 100 ml to 200 ml, recommended type Pt II. 6.13 Platinum-tipped tongs. 6.14 Ring stand, with crucible support. 6.15 Sieves, 0,250 mm and 0,075 mm, conforming to ISO 3310-
40、1. 6.16 Tungsten carbide mill, laboratory size. 6.17 Vacuum filtration apparatus. 6.18 Filter paper, sized to fit a vacuum filtration apparatus, of fine porosity, slow flow rate, 2,5 m particle retention. 6.19 Ultrasonic bath. 7 Reagents During the analysis, unless otherwise stated, use only reagent
41、s of recognized analytical grade and distilled or demineralized water, or water of equivalent purity. 7.1 Water, complying with grade 2 of ISO 3696:1987. 7.2 Argon gas supply, welding grade. 7.3 Lithium metaborate (LiB0 2 ), powder (high purity) or lithium tetraborate (Li 2 B 4 0 7 ), powder (high p
42、urity). The use of a blend containing 66 % lithium metaborate (LiB0 2 ) and 34 % lithium tetraborate (Li 2 B 4 0 7 ) is recommended: a commercially available product is known as “Spectromelt A12“ 1) . 7.4 Nitric acid, 65 % mass fraction (high purity). 7.5 Solution No. 1, nitric acid, prepared by dil
43、uting 400 ml of concentrated HNO 3(65 % mass fraction) to 2 000 ml with water. NOTE The mass fraction of concentrated HNO 3is 65 %. The dilution of 400 ml HNO 3(65 % mass fraction) to 2 000 ml with water gives a mass fraction of 13 % HNO 3with a density of 1,072. The result is a mass fraction of 12,
44、1 %. 7.6 Solution No. 2, standard and sample solution additive. Weigh 20 0,1 g, of lithium borate into a 100 ml to 200 ml platinum dish. Place in a furnace at 1000 C for 5 min, to fuse to a liquid. Remove and cool. Place the cooled platinum dish containing the fused recrystallized lithium borate and
45、 a magnetic stirring bar (6.6) into a 2 litre glass beaker. Add 1 000 ml of Solution No. 1. Heat gently and stir the solution on the magnetic stirring hotplate (6.7) until the lithium borate completely dissolves. After dissolution, remove the platinum dish with a glass rod. Rinse the platinum dish a
46、nd glass rod with water into the lithium borate solution. Immediately transfer the warm solution quantitatively to a 2 litre volumetric flask. Dilute to about 1 800 ml with water to avoid crystallization. Mix the solution and cool to room temperature. Dilute to volume with water, mix thoroughly, and
47、 vacuum-filter the entire solution through filter paper. 1)Spectromelt A12 is an example of a suitable product available commercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this product.ISO 14435:2005(E)
48、 ISO 2005 All rights reserved 5 50 ml of Solution No. 2 contains exactly 0,5 g of lithium borate and 25 ml of Solution No. 1. 7.7 Standard stock solutions, use certified ready-to-use single- or multi-element standard stock solutions with a concentration of 1 000 g/ml for each element in nitric acid.
49、 CAUTION To minimize the potential of contamination, prepare the platinum ware by boiling in dilute HNO 35 % HNO 3(volume fraction) + 95 % water (volume fraction) and rinsing thoroughly with water. After this initial cleaning, handle the platinum ware with clean platinum-tipped tongs and protect from all sources of contamination. Similarly, clean all glassware used in the analyses with acid. 8 Sample preparation Take a sample in accordance with ISO 6375. 8.1 Crush and divide the sample to ob
