1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58in analytical samples Gravimetric, Karl Fischer and mass-loss methods ICS 73.060.10Iron ores Determ
2、ination of hygroscopic moisture BRITISH STANDARDBS ISO 2596:2006BS ISO 2596:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2006 BSI 2006ISBN 0 580 48834 9Cross-referencesThe British Standards which implement international publica
3、tions referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necess
4、ary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the ISO title page, pages ii to vi, pages 1 to 3
5、2, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsA list of organizations represented on this committee can be obtained on request to its secretary. present
6、 to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.National forewordThis British Standard reproduces verbatim ISO 2596
7、:2006 and implements it as the UK national standard. It supersedes BS ISO 2596:1994 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores, which has the responsibility to: aid enquirers to understand the text;Reference numberISO 2596:2006(E
8、)INTERNATIONAL STANDARD ISO2596Fifth edition2006-05-01Iron ores Determination of hygroscopic moisture in analytical samples Gravimetric, Karl Fischer and mass-loss methods Minerais de fer Dtermination de lhumidit hygroscopique dans les chantillons pour analyse Mthodes gravimtrique, selon Karl Fische
9、r et par perte de masse BS ISO 2596:2006ii iiiContents Page Foreword. v Introduction . vi 1 Scope . 1 2 Normative references . 1 3 Method 1 Gravimetric method 2 3.1 Principle. 2 3.2 Reagents 2 3.3 Apparatus 3 3.4 Sampling and samples. 4 3.4.1 Laboratory sample 4 3.4.2 Preparation of test sample. 4 3
10、.5 Procedure 4 3.5.1 Apparatus conditioning 4 3.5.2 System checks 5 3.5.3 Blank test. 5 3.5.4 Check test 5 3.5.5 Determination 6 3.6 Expression of results . 6 3.6.1 Calculation of hygroscopic moisture content . 6 3.6.2 Hygroscopic moisture correction of analytical test portion mass 7 4 Method 2 Karl
11、 Fischer volumetric method 7 4.1 Principle. 7 4.2 Reagents 7 4.3 Apparatus 8 4.4 Sampling and samples. 9 4.4.1 Laboratory sample 9 4.4.2 Preparation of test sample. 10 4.5 Procedure 10 4.5.1 Conditioning of drying tube. 10 4.5.2 Preparation of titration unit . 10 4.5.3 Titration 10 4.5.4 Blank test.
12、 11 4.5.5 Check test 11 4.5.6 Determination 11 4.6 Expression of results . 12 4.6.1 Calculation of hygroscopic moisture content . 12 4.6.2 Hygroscopic moisture correction of analytical test portion mass 12 5 Method 3 Karl Fischer coulometric method 13 5.1 Principle. 13 5.2 Reagents 13 5.3 Apparatus
13、14 5.4 Sampling and samples. 15 5.4.1 Laboratory sample 15 5.4.2 Preparation of test sample. 15 5.5 Procedure 15 5.5.1 Preparation of titration unit . 15 5.5.2 Conditioning of drying tube. 15 5.5.3 Blank test. 16 5.5.4 Check test 16 BS ISO 2596:2006iv 5.5.5 Determination 17 5.6 Expression of results
14、 17 5.6.1 Calculation of hygroscopic moisture content 17 5.6.2 Hygroscopic moisture correction of analytical test-portion mass 18 6 Method 4 Mass-loss method . 18 6.1 Principle . 18 6.2 Reagents 18 6.3 Apparatus. 19 6.4 Sampling and samples . 20 6.4.1 Laboratory sample 20 6.4.2 Preparation of test s
15、ample. 20 6.5 Procedure. 20 6.5.1 Apparatus conditioning 20 6.5.2 Check test 21 6.5.3 Determination 21 6.6 Expression of results 22 6.6.1 Calculation of hygroscopic moisture content 22 6.6.2 Hygroscopic moisture correction of analytical test portion mass 22 Annex A (informative) Gravimetric and Karl
16、 Fischer apparatus 23 Annex B (informative) Drying tube 24 Annex C (informative) Titanium absorption tube 26 Annex D (informative) Volumetric titration cell . 27 Annex E (informative) Coulometric titration cell . 28 Annex F (informative) Modified weighing chamber apparatus 29 Annex G (informative) M
17、odified weighing chamber 30 Annex H (informative) Parcher equipment. 31 Bibliography . 32 BS ISO 2596:2006vForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is no
18、rmally 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 committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in
19、 the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepa
20、re International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that so
21、me 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 2596 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis. This fifth editio
22、n cancels and replaces the fourth edition (ISO 2596:1994), which has been technically revised. BS ISO 2596:2006vi Introduction In the analysis of iron ores, the reporting limit of the analytical value of each constituent on a dry sample basis can be achieved by using predried samples. However, with
23、certain ore types, where the constituent being determined is above a certain concentration level as specified in the scope, this technique can produce erroneous results. In these cases, for the calculation of analytical values of the other constituents in the ore to a dry sample basis, a direct dete
24、rmination of the hygroscopic moisture content becomes necessary. BS ISO 2596:20061Iron ores Determination of hygroscopic moisture in analytical samples Gravimetric, Karl Fischer and mass-loss methods 1 Scope This International Standard specifies the following four test methods for the determination
25、of the hygroscopic moisture content of test samples: Method 1 Gravimetric method; Method 2 Karl Fischer volumetric method; Method 3 Karl Fischer coulometric method; Method 4 Mass-loss method. Any of these methods is applicable wherever the analytical value of a chemical constituent is to be calculat
26、ed to a dried sample basis in the following ore types. a) Processed ores containing metallic iron (direct reduced iron). b) Natural or processed ores in which the sulfur content is greater than 0,2 % (mass fraction). c) Natural or processed ores in which the combined water is greater than 2,5 % (mas
27、s fraction). Any of these methods is applicable to a concentration range of 0,05 % (mass fraction) to 4,5 % (mass fraction) hygroscopic moisture. NOTE 1 Where the reportable moisture content of a commercial consignment of ore is required, the procedure in ISO 3087 is used. NOTE 2 With natural or pro
28、cessed ores outside the field of application specified in a), b) or c), a determination of a constituent at any level of concentration may be conducted using any of these methods, or as specified in ISO 7764. NOTE 3 Alternatively, the loss or ignition content may be measured as an estimate of the co
29、mbined water content. 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, the latest edition of the referenced document (including any amendments) applies. ISO
30、760, Determination of water Karl Fischer method (General method) ISO 3082, Iron ores Sampling and sample preparation procedures BS ISO 2596:20062 3 Method 1 Gravimetric method 3.1 Principle The hygroscopic moisture content of an environmentally equilibrated test portion is determined at 105 C 2 C wi
31、thin a drying tube, into which dry nitrogen is passed (at a rate of 100 ml/min to 200 ml/min). Evolved moisture (swept by gas) is collected in an absorption tube containing anhydrous magnesium perchlorate, and the percentage moisture content is determined via the corrected mass increase of the tube.
32、 3.2 Reagents 3.2.1 Desiccant Anhydrous magnesium perchlorate Mg(ClO4)2of size 0,80 mm to 1,25 mm, to ensure carrier-gas water-vapour pressures below 5 g H2O/l. As measurement accuracy and precision are highly dependent on blank determinations, the stability of residual background moisture shall be
33、controlled as a function of combining capacity. The combining capacity (Cc) is calculated as a percentage of desiccant and residual carrier-gas moisture content using the following equation: 1c2()mLNCm= (1) where m1is the mass of residual carrier-gas moisture content, in centigrams per litre, where
34、m1= 0,000 1 cg/l for aluminium calcium silicate molecular sieves, 0,000 2 cg/l for silica gel desiccant; L is the number of litres of gas per bottle; N is the number of gas bottles consumed; m2is the mass, in grams, of desiccant added to drying tower. For successful drying, the combining capacity sh
35、ould be restricted to 10 % (mass fraction). WARNING Magnesium perchlorate is a powerful oxidant and cannot be allowed to be exposed to organic materials. When exhausted, it should not be discarded into waste bins, but should be washed down the sink. 3.2.2 Aluminium calcium silicate molecular sieves,
36、 made of 1/16 in pellets. Before use, sieves shall be dried by heating to 400 C for 4 h. NOTE This limit is based on extending the service life of secondary desiccants (magnesium perchlorate), by limiting input stream contaminants. 3.2.3 Silica gel desiccant, blue self-indicating. Before use, gel sh
37、all be dried by heating to 105 C for 4 h. BS ISO 2596:200633.2.4 Copper(II) sulfate pentahydrate analytical reagent grade (AR) (CuSO45H2O), free-flowing crystalline material, press-crushed if necessary under a pestle by hand, without grinding, to a size of approximately 1 mm. 3.2.5 Nitrogen, filtere
38、d, predried, oil-free, containing less than 10 l of oxygen per litre at a pressure of approximately 35 kPa to 50 kPa above atmospheric pressure. 3.3 Apparatus NOTE A suitable apparatus for the determination is shown diagrammatically in Annex A. 3.3.1 Balance, capable of reading the mass of the absor
39、ption vessel to 0,1 mg. 3.3.2 Oven, preferably of the aluminium metal-block type, capable of accommodating one, but preferably several, glass drying tubes (3.3.3) and of maintaining a temperature within the range 105 C 2 C over a minimum tube length of 160 mm. 3.3.3 Borosilicate glass drying tubes a
40、nd connections, fitted with Viton “O”-ring-seal pushrod cap assemblies. NOTE A suitable drying tube is shown diagrammatically in Annex B. 3.3.4 Drying towers, of capacity 250 ml, one filled with molecular sieves (3.2.2) or silica gel (3.2.3) and the other packed with magnesium perchlorate desiccant
41、(3.2.1), to dry the stream of nitrogen (3.2.5) entering the drying tubes. Molecular sieves (3.2.2) and silica gel (3.2.3) drying towers shall be repacked with freshly dried desiccants fortnightly. 3.3.5 Flowmeters, capable of measuring a flow rate within the range 100 cm3/min to 200 cm3/min. If a pr
42、essure drop over a constriction is used as a means of measuring flow rate, the manometer liquid shall be a non-volatile oil. 3.3.6 Absorption tubes, manufactured of chemically inert conducting material to minimize static charging effects (titanium is preferred), with pan-balance location pads to min
43、imize corner-load weighing errors. NOTE A suitable tube is shown in Annex C. Tubes shall be of suitable design (8 mm ID 300 mm) to contain sufficient desiccant (3.2.1) to remove the moisture completely from the stream of nitrogen (3.2.5). The tubes should have sealable inlet and outlet connections a
44、nd the direction of gas flow should be unambiguously identified. Desiccants shall be firmly packed to prevent “channelling” and be retained in position with glass-wool plugs. 3.3.7 Guard tubes, of a suitable design, containing magnesium perchlorate desiccant (3.2.1) to prevent back diffusion of mois
45、ture into absorption tubes. 3.3.8 Sample boats, of an inert and stable material, such as glass, stainless steel or glazed porcelain. Approximate dimensions are 100 mm 20 mm 10 mm. Before use, boats should be dried at approximately 105 C, and then cooled to ambient temperature in a desiccator. Boats
46、shall be stored in a desiccator prior to use. 3.3.9 Filter discs, of sintered metal, sintered glass or similar, inserted in the flexible connections between the drying and absorption tubes. BS ISO 2596:20064 3.3.10 Flexible connections The selection of polymeric tubing shall be made by taking into c
47、onsideration that some materials are permeable to moisture. Annealed copper/stainless steel tubing is preferable. Swagelock-type connectors and quick-release neoprene “O”-ring connector joints are recommended. On serviceable components that necessitate removal, quick-release neoprene “O”-ring connec
48、tor joints shall be used. Glass ends should be sufficiently smoothed to minimize coupling-seal damage. 3.3.11 Flow-control needle valve, placed on the inlet of each flowmeter. 3.4 Sampling and samples 3.4.1 Laboratory sample For analysis, use a laboratory sample of particle size less than 100 m or l
49、ess than 160 m, which has been taken and prepared in accordance with ISO 3082. 3.4.2 Preparation of test sample Thoroughly mix the laboratory sample and, taking multiple increments, extract a test sample in such a manner that it is representative of the whole contents of the container. The test sample is brought into equilibrium with the laboratory atmosphere by exposure for at least 2 h on an inert tray at a layer density not greater than 0,1 g/cm2. The sample shall be thoroughly mixe
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