1、BRITISH STANDARD BS 5551-2.8: 1991 ISO 8358:1991 Fertilizers Part 2: Sampling Section 2.8 Methods for preparation of samples of solid fertilizer for chemical and physical analysisBS5551-2.8:1991 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committe
2、e, waspublished under the authorityof the Standards Boardand comes intoeffecton 30August1991 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/37 Draft for comment 89/55127 DC ISBN 0 580 19899 5 Committees responsible for this British Standard The
3、preparation of this British Standard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/37, upon which the following bodies were represented: Association for Consumer Research (ACRE) Association of Public Analysts British Aggregate Construction Materials Ind
4、ustries British Coal Corporation Chemical Industries Association Department of Trade and Industry (Laboratory of the Government Chemist) Fertiliser Manufacturers Association Ltd. Institute of Trading Standards Administration Ministry of Agriculture, Fisheries and Food Ministry of Defence Amendments
5、issued since publication Amd. No. Date CommentsBS5551-2.8:1991 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Principle 1 5 Apparatus 1 6 Procedure 1 7 Labelling 3 8 Sample preparation report 3 Figure 1
6、Schematic diagram of sampling process 4 Publication(s) referred to Inside back coverBS5551-2.8:1991 ii BSI 10-1999 National foreword This Section of BS5551has been prepared under the direction of the Chemicals Standards Policy Committee. For some years the United Kingdom has participated in the stan
7、dardization of methods of sampling fertilizers through Subcommittee 2, Sampling, of Technical Committee 134, Fertilizers and soil conditioners, of the International Organization for Standardization (ISO). As international agreement is reached on the methods, it is proposed to publish them as Section
8、s of BS 5551. This British Standard is published in four Parts, each Part being subdivided into Sections and, where appropriate, Subsections. The four Parts are: Part 1: Terminology and labelling; Part 2: Sampling; Part 3: Physical analysis; Part 4: Chemical analysis. This Section of Part2is identic
9、al with ISO 8358:1991 “Solid fertilizers Preparation of samples for chemical and physical analysis”. With reference to 5.4, woven wire test sieves complying with BS410:1986 are technically equivalent to, and may be used in place of, those complying with ISO3310-1:1982. The Technical Committee has re
10、viewed the provisions of ISO 3310-1:1982 and has decided that they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance
11、 with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard BS 5551 Fertilizers ISO 5306:1983 Section 2.2:1984 Presentation of sampling reports (Identical) ISO 7410:1983 Section 2.4:1983 Practical arrangem
12、ents for final samples (Identical) ISO/TR 7553:1987 Section 2.7:1988 Recommendations for minimum mass of increment of a solid fertilizer to be taken to be representative of the total sampling unit (Identical) ISO 7742:1988 Section 2.5:1989 Method for reduction of samples of solid fertilizers (Identi
13、cal) ISO 8157:1984 Section 1.2:1986 Glossary of terms (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorpo
14、rated. This will be indicated in the amendment table on the inside front cover.BS5551-2.8:1991 BSI 10-1999 1 1 Scope This International Standard specifies methods for the preparation of test samples and test portions from laboratory samples of solid fertilizer for subsequent chemical or physical ana
15、lysis. It does not cover the preparation of samples for certain physical tests which require test portions of more than2kg. This International Standard is applicable to all solid fertilizers. 2 Normative references The following standards contain provisions which, through reference in this text, con
16、stitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions o
17、f the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3310-1:1982, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth. ISO 5306:1983, Fertilizers Presentation of sampling reports. ISO 7410:1983,
18、Fertilizers and soil conditioners Final samples Practical arrangements. ISO/TR 7553:1987, Fertilizers Sampling Minimum mass of increment to be taken to be representative of the total sampling unit. ISO 7742:1988, Solid fertilizers Reduction of samples. ISO 8157:1984, Fertilizers and soil conditioner
19、s Vocabulary. 3 Definitions For the purposes of this International Standard, the definitions given in ISO8157and the following definitions apply. 3.1 reduction the process of producing a representative smaller mass of fertilizer from a larger mass, with the remainder being discarded 3.2 division the
20、 process of producing a number of representative smaller portions, approximately equal in mass to each other, from a larger mass with little or no remainder 4 Principle Reduction and division of the laboratory sample, as necessary, to produce test samples. Preparation of test portions from the test
21、samples by division, with or without previous grinding, or by combination, as appropriate. 5 Apparatus 5.1 Rotary sample divider or riffle divider, satisfying the requirements of ISO 7742. 5.2 Sample grinder Any machine used for grinding samples as required by this International Standard shall be ch
22、ecked for satisfactory performance. Particular points to be checked are: a) the fineness of grinding achieved; b) the temperature rise of the material being ground. The grinder shall be capable of taking the whole sample at one pass and should preferably be totally enclosed. It shall have a screen,
23、or other mechanism without a screen, which will allow the ground material to pass through the machine into a collecting vessel and away from the cutters or grinding discs, to avoid over-grinding. In the case of a grinder with screens, the fineness of grind can be adjusted by the fitting of different
24、 mesh screens. Grinding shall continue until as much as possible of the fertilizer has passed through the machine. NOTEIf the grinder is of the open type, the moisture content of the fertilizer may change significantly during grinding. 5.3 Mortar and pestle, of suitable material and size. 5.4 Test s
25、ieves, complying with the requirements of ISO 3310-1, of nominal aperture sizes1,0mm,0,5mm and0,18mm. NOTEIn cases where national regulations or the nature of the material require sieves of different aperture sizes, these may be used but the fact should be noted in the sample preparation report. 5.5
26、 Sample containers, made of plastics material and/or glass, or any other material of adequate resistance and fitted with airtight closures (see ISO 7410). 6 Procedure (see Figure 1) WARNING All operations connected with this procedure should be carried out as quickly as possible to minimize the abso
27、rption or loss of water.BS5551-2.8:1991 2 BSI 10-1999 6.1 Preparation of test samples in their original condition Mix the whole of the laboratory sample and follow the procedure described in ISO 7742, to reduce (if necessary) and divide the total mass to obtain the appropriate number of representati
28、ve test samples, each of about0,5kg in mass. Reject, by random selection, any test samples in excess of those required and place the remaining N test samples in some of the airtight containers (5.5). NOTEThe maximum number of test samples which can be produced by this method will depend on the mass
29、of the original laboratory sample. The minimum number of0,5kg test samples which is required will depend on the nature of the analyses to be carried out and the number of replicates required. In some instances, when only chemical analyses are to be carried out, only a small laboratory sample will be
30、 available and the whole of this sample will be used as the test sample. 6.2 Further preparation for test samples which must remain in their original condition Test samples in this category include all those for physical testing, those for certain chemical analyses and those which, by their nature,
31、must not be ground. 6.2.1 Preparation of test portions for physical testing If the mass of the test portion required is greater than0,5kg, select at random two or more of the N test samples (6.1). Mix these together and, if the mass required is not an exact multiple of0,5kg, reduce it to the require
32、d size by following the procedure described in ISO 7742. If the mass of test portion required is less than0,5kg, select at random one of the N test samples (6.1) and continue the reduction and division following the procedure described in ISO7742, until test portions of the required mass for the tes
33、t are obtained. During the division process, replicate test portions will be obtained and these are suitable for replicate tests without further treatment. Discard any unwanted material. NOTERepresentativity of the sample may be lost during this further sub-division and reference should be made to I
34、SO/TR 7553. 6.2.2 Preparation of test portions for moisture analysis Test portions for moisture analysis shall not be ground because grinding is likely to alter the moisture content of the fertilizer. If necessary, the size of the larger particles may be reduced by crushing. Select, at random, one o
35、f the N test samples (6.1) and carry out reduction and division, following the procedure described in ISO 7742, until test portions of the required size are obtained. 6.2.3 Preparation of test portions for other chemical analyses Some chemical analyses have to be performed on test portions taken fro
36、m samples which have not been ground. Reference should be made to this in the relevant analytical method. Some fertilizers decompose during grinding and it is essential that these are not ground before starting analysis. The following fertilizers may be subject to such considerations: calcium nitrat
37、e, calcium magnesium nitrate, sodium nitrate, calcium cyanamide, ammonium sulfate, ammonium nitrate with more than30% of N, urea, basic slag, natural phosphate partially solubilized, dicalcium phosphate, sintered alumina and calcium phosphate and soft natural phosphate and slow-release fertilizers.
38、Select, at random, one of the N test samples (6.1) and carry out reduction and division following the procedure described in ISO7742until test portions of the required size are obtained. 6.3 Further preparation for test samples for chemical analysis See 6.2.2 and 6.2.3 for those special cases where
39、the test sample must remain in its original condition. WARNING Care should be taken during the following grinding operation that the temperature of the fertilizer does not rise above45 C, to avoid loss of ammonia, etc. 6.3.1 General Select, at random, one of the N test samples (6.1) and follow prefe
40、rably the procedure described in6.3.2 or, if a suitable sample grinder is not available, that specified in 6.3.3, or, if special treatment is necessary, that specified in 6.3.4, 6.3.5 or 6.3.6 as appropriate. 6.3.2 Use of sample grinder Grind the test sample in the grinder (5.2) until all the sample
41、 has passed through, or for the specified time, depending on the type of grinder. To check that the grinding has been adequate, thoroughly mix and sieve a small representative portion of the ground sample through the test sieve of aperture size0,5mm (5.4) and discard it. If the whole of this portion
42、 does not pass through the sieve, return the sample to the grinder and repeat the grinding until satisfactory grinding is achieved. NOTEFor mixtures containing one or more very hard components, it may be difficult to grind and homogenize all the components. The procedure given in this subclause shou
43、ld not be used if the overgrinding of some of the softer components is to be avoided. In these, and only these, cases it will be necessary to prepare two or more parts of the same sample.BS5551-2.8:1991 BSI 10-1999 3 6.3.3 Use of mortar and pestle Sieve the total laboratory sample on the test sieve
44、of aperture size0,5mm (5.4). Grind the residue on the sieve, using the mortar and pestle (5.3), until all the material passes, without residue, through the sieve. Grinding to the fineness required shall in all cases be avoided where this will affect the solubility in various reagents. Carefully homo
45、genize all the sample. NOTEIn this case the moisture content of the fertilizer may change significantly during grinding. 6.3.4 Products which are difficult to grind mechanically Products with abnormal moisture content or products such as superphosphate may become doughy if ground mechanically. In th
46、ese cases crush the fertilizer in the mortar (5.3) so that all the material passes through the test sieve of aperture size1,0mm (5.4). 6.3.5 Organic matter Some organic materials may be of such a nature that the procedures described above cannot be used. Examples of these are: fresh guano, leather,
47、wool and animal residues. In these cases the analyst should use the best practicable means to reduce the material size and to obtain a representative sample and should record the method used in the test report. NOTEMany of these materials may be ground after intense cooling, for example in liquid ni
48、trogen. 6.3.6 Fertilizers comprising several different materials These fertilizers include materials with marked differences in texture or mechanical properties (hardness, density, etc.). They may be difficult to grind completely, e.g. mixtures of organic and inorganic materials, or they may segrega
49、te during handling, e.g. potassium magnesium sulfate. Special procedures are necessary in these cases. A grinding machine capable of grinding the whole of the sample in one pass to the required fineness is strongly recommended. Follow the procedure specified in 6.3.2 using the test sieve of aperture size0,18mm (5.4). 6.3.7 Foreign matter If the test sample contains foreign matter which cannot be ground, remove and weigh this, and allow for it in the results of the analysis. This material should be retained and, if possible, its nature record
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