1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58loss of bulk material on dryingICS 73.060.99Copper, lead, zinc and nickel concentrates Determinatio
2、n of mass BRITISH STANDARDBS ISO 10251:2006BS ISO 10251:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2006 BSI 2006ISBN 0 580 48965 5request to its secretary.Cross-referencesThe British Standards which implement international pu
3、blications 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 n
4、ecessary 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 v, a blank
5、page, pages 1 to 13 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 present to the responsible internatio
6、nal/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 10251:2006 and implements it as th
7、e UK national standard. The UK participation in its preparation was entrusted to Technical Committee NFE/36, Copper, lead and zinc ores and concentrates, which has the responsibility to: aid enquirers to understand the text;INTERNATIONALSTANDARDISO10251Second edition2006-05-01Reference numberISO 102
8、51:2006(E)Copper, lead, zinc and nickel concentrates Determination of mass loss of bulk material on dryingConcentrs de cuivre, de plomb, de zinc et de nickel Dtermination de la perte de masse au schage du matriau en vracBS ISO 10251:2006iiiiiContents Page1 Scope 12 Normative references 13 Terms and
9、definitions 14 Drying method . 25 Apparatus . 46 Processing of samples 47 Moisture samples 48 Procedure for drying samples to constant mass . 59 Calculation . 610 Test report 9Annex A (normative) Test for susceptibility of concentrates to oxidation, decomposition and sublimation . 10Annex B (normati
10、ve) Determination of moisture content of cohesive or wet concentrates . 11Annex C (informative) Example of a work sheet for the determination of moisture contentof each test portion in accordance with this International Standard 12Bibliography . 13BS ISO 10251:2006ivForewordISO (the International Or
11、ganization for Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The work of preparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablish
12、ed has the right to be represented on that committee. International organizations, governmental andnon-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the InternationalElectrotechnical Commission (IEC) on all matters of electrotechnical standardization.In
13、ternational Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publica
14、tion as anInternational Standard requires approval 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 patentrights. ISO shall not be held responsible for identifying any or all such patent rights
15、.ISO 10251 was prepared by Technical Committee ISO/TC 183, Copper, lead, zinc and nickel ores andconcentrates.This second edition cancels and replaces the first edition (ISO 10251:1997), which has been technicallyrevised.BS ISO 10251:2006vIntroductionReference to the percentage mass loss as moisture
16、 content is appropriate because, although oxidation,decomposition or sublimation of elemental sulfur may contribute, most of the mass loss on drying is due to lossof moisture.When oxidation, decomposition or sublimation of elemental sulfur has been shown to occur or volatile organicflotation reagent
17、s such as kerosene are present, the chemical analysis test sample should be prepared from thedried moisture test portions. Under these circumstances, the sampling scheme established in accordance withISO 12743 must ensure that moisture samples and test portions are sufficiently representative for su
18、bsequentchemical analysis. Where oxidation is a problem, an inert atmosphere may also be used during the dryingstage. Annex A provides a procedure by which it can be determined whether or not a concentrate is susceptibleto oxidation, decomposition or sublimation.BS ISO 10251:2006blank1Copper, lead,
19、zinc and nickel concentrates Determination of mass loss of bulk material on dryingWARNING This International Standard may involve hazardous materials, operations and equipment.This International Standard does not purport to address all of the safety issues associated with its use.It is the responsib
20、ility of the user to establish appropriate health and safety practices and determine theapplicability of regulatory limitations prior to use.1ScopeThis International Standard specifies methods for the determination of moisture content of a lot of copper, lead,zinc or nickel concentrate, defined as t
21、he percentage mass loss of the moisture test portion under theconditions of drying specified in this document.In order to obtain an unbiased estimate of the metal content of the lot, it is important that the same dryingconditions are used for the determination of bulk and hygroscopic moisture or for
22、 preparing a predried testportion.This International Standard is not applicable to drying samples used for determination of volatile elements suchas mercury and sulfur. Such samples are allowed to dry at ambient temperature, and a hygroscopic moisturedetermination is carried out according to ISO 959
23、9 at the time of chemical analysis.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenced document(including any amendments) app
24、lies.ISO 12743, Copper, lead, zinc and nickel concentrates Sampling procedures for determination of metal andmoisture content3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1 representative samplequantity of concentrate representing a larger mass
25、 of concentrate with both precision and bias withinacceptable limits3.2 lotquantity of concentrate to be sampled3.3 lot samplequantity of concentrate that is representative of the lotBS ISO 10251:200623.4 sub-lotsubdivided parts of a lot that are processed separately, each of them producing a subsam
26、ple which is analysedseparately, e.g. for moisture determination3.5 subsamplequantity of concentrate that is representative of the sub-lot3.6 incrementquantity of concentrate selected by a sampling device in one operation3.7 moisture samplerepresentative quantity of concentrate from which test porti
27、ons are taken for moisture determinationNOTE Alternatively, the whole moisture sample may be dried to determine its moisture content.3.8 laboratory samplesample that is processed so that it can be sent to the laboratory and used for further processing and selectionof one or more test samples for che
28、mical analysis3.9 common samplerepresentative quantity of concentrate that is dried to determine its mass loss and subsequently used for furtherprocessing and selection of one or more test samples for chemical analysis3.10 test samplerepresentative quantity of concentrate obtained for a laboratory s
29、ample when additional preparation, such asdrying or hygroscopic moisture determination, is needed prior to selection of one or more test portions3.11 test portionrepresentative quantity of concentrate taken from a moisture sample, a laboratory sample or a test sample thatis submitted to moisture det
30、ermination or analysis in its entirety4 Drying method4.1 GeneralTest portions are dried at until constant mass is obtained and the moisture content determinedas the percentage mass loss on drying. However, drying to constant mass can be difficult or impossible if theconcentrate is susceptible to oxi
31、dation, decomposition or sublimation of elemental sulfur, or volatile organicflotation reagents such as kerosene are present (see Annex A). Under these circumstances, using a commonsample for moisture determination and chemical analysis, drying in an inert atmosphere, or interrupting thedrying is ap
32、plied. Of these alternatives, the use of a common sample is the best approach, although care needsto be taken to ensure that the moisture samples and test portions are sufficiently representative for subsequentchemical analysis.105C 5CBS ISO 10251:20063One of the following drying methods is selected
33、 to suit the particular concentrate. A flow chart for selecting thecorrect drying method is given in Figure 1, noting that use of a common sample is applicable in all cases.4.2 Method 1Where the test portion can be dried to constant mass and the concentrate passes the test in Annex A, aseparate samp
34、le for moisture determination or a common sample is dried to constant mass.4.3 Method 2Where the test portion can be dried to constant mass but the test in Annex A results in a higher mass (indicatingthat the concentrate is susceptible to oxidation) moisture and chemical analysis samples are dried t
35、o constantmass in an inert atmosphere, or a common sample is dried to constant mass.4.4 Method 3Where the test portion can be dried to constant mass but the test in Annex A results in a lower mass (indicatingthat the concentrate may be losing organics over an extended period) a common sample is drie
36、d to constantmass.Figure 1 Procedure for selection of appropriate drying methodBS ISO 10251:200644.5 Method 4Where the test portion cannot be dried to constant mass and continues to lose mass over long periods(indicating that the concentrate may be losing hydrated water, decomposing or subliming) a
37、common sample isused, with interruption of drying after a period determined in accordance with Clause 8 for each concentratetype, and no further drying prior to analysis.4.6 Method 5Where the test portion cannot be dried to constant mass and after the initial drying period continues to gainmass (ind
38、icating that the concentrate may be oxidizing even when dry) moisture and chemical analysis samplesare dried to constant mass in an inert atmosphere, or a common sample is used with interruption of drying aftera period determined in accordance with Clause 8 for each concentrate type, and no further
39、drying prior toanalysis.5 Apparatus5.1 Drying oven, ventilated, with forced circulation of air or inert gas, regulated at a temperature of.5.2 Top-loading balance, having a minimum precision of as specified in Table 1.5.3 Drying trays, having dimensions that permit the sample to be spread to a thick
40、ness of less than .The trays shall be made of corrosion-resistant and heat-resistant material such as stainless steel, glass orenamel plate.The weighing platform should be protected from heat transfer material, e.g. by a layer of polystyrene.6 Processing of samplesMoisture samples shall be taken and
41、 processed in accordance with ISO 12743.If the concentrate is cohesive or excessively wet, the sample may be predried until sample preparation can beconducted without difficulty. The predried moisture content and the total moisture content of the sample shall bedetermined by the procedure specified
42、in Annex B.7 Moisture samples7.1 GeneralMoisture samples shall be taken as close to the point (position and time) of mass determination as practicable.Samples shall then be prepared and the test portions weighed immediately to minimize bias.Table 1 Mass of sample and minimum precision of balance and
43、 weighingMass of sample Minimum precision of balance and weighing10,120250510 120 250 5105C 5C0,01 %30 mmkg g13 mmBS ISO 10251:20065Breaking up of agglomerates by screening is not permitted, because this will result in a change in moisturecontent.NOTE If agglomerates are present, the minimum mass of
44、 the test portion specified in 7.2, 7.3 and 7.4 or the number ofmoisture determinations may have to be increased to obtain the required precision.7.2 From a single lot sampleWhere a single lot sample is obtained from a lot, four test portions of not less than shall be taken asspecified in Table 2 an
45、d two of these shall be submitted initially for the determination of moisture content. Thetwo reserve test portions shall be weighed in accordance with the procedure specified in Clause 8 and set asideon a covered tray.7.3 From subsamplesWhere subsamples from a lot are not combined into a single lot
46、 sample, the minimum number of test portionsspecified in Table 2 shall be taken from each subsample and submitted for the determination of moisturecontent. Each test portion shall be not less than in mass.Where a subsample is prepared from each sub-lot, the mass of each sub-lot shall be recorded at
47、the same timefor calculation of the moisture content of the lot.7.4 From incrementsWhere moisture determination is conducted on each increment, one test portion of not less than shall betaken from each increment as specified in Table 2 and submitted for the determination of moisture content.The mass
48、 of each stratum shall be recorded at the same time for calculation of the moisture content of the lot.8 Procedure for drying samples to constant massWeigh the drying tray and record the mass ( ) to the precision specified in Table 1. Transfer the test portion(not less than ) to the drying tray, spr
49、eading it evenly using a suitable implement, and weigh immediately.Record the mass ( ) to the precision specified in Table 1.Place the tray and test portion in the drying oven and dry at for a predetermined time.The initial drying time has to be determined empirically. Sixteen hours is sufficient for most cases and can betaken as a guide.Once the drying period has commenced, no other wet samples should be placed in the same drying oven.Remove the tray and test portion from the oven and weigh while still hot. Dry the
