BS 7319-2-1990 Analysis of sodium chloride for industrial use - Method for determination of moisture content《工业用氯化钠的分析 含水量的测定方法》.pdf

1、BRITISHSTANDARD BS7319-2: 1990 ISO2483:1973 Analysis of sodium chloride for industrial use Part2: Method for determination of moisture contentBS7319-2:1990 This BritishStandard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the authorityof th

2、e Board of BSI andcomes into effect on 30September1990 BSI12-1999 The following BSI references relate to the work on this standard: Committee references CIC/22, FAC/23 Draft for comment88/55615DC ISBN 0 580 185317 0 Committees responsible for this BritishStandard The preparation of this BritishStand

3、ard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/22, upon which the following bodies were represented: British Association for Chemical Specialities Chemical Industries Association Man-made Fibres Producers Committee Soap and Detergent Industry Associa

4、tion Textile Research Council (FCRA) The following bodies were also represented in the drafting of the standard, through Technical Committee FAC/23: AFRC Institute of Food Research Creamery Proprietors Association Department of Trade and Industry (Laboratory of the Government Chemist) Food and Drink

5、 Federation Milk Marketing Board for Northern Ireland Royal Association of British Dairy Farmers Salt Manufacturers Association Amendments issued since publication Amd. No. Date CommentsBS7319-2:1990 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope a

6、nd field of application 1 2 Principle 1 3 Apparatus 1 4 Sampling and samples 1 5 Procedure 1 6 Expression of results 1 7 Test report 1 Publication(s) referred to Inside back coverBS7319-2:1990 ii BSI 12-1999 National foreword BS7319 has been prepared under the direction of the Chemicals Standards Po

7、licy Committee, at the request of Technical Committee FAC/23, Salt, primarily to provide appropriate methods for determination of vacuum salt for food use as specified in BS998:1990. The methods for determination were previously published as appendices to BS998:1969. A list of the Parts of BS7319 is

8、 given in Part1. This Part of BS7319 is identical with ISO2483:1973 “Sodium chloride for industrial useDetermination of the loss of mass at110 C” published by the International Organization for Standarization (ISO). It supersedes Appendix D ofBS998:1969, which is withdrawn. Additional information. W

9、ith reference to clause4, the method referred to has now been published as ISO8213:1986 “Chemical products for industrial use Sampling techniquesSolid chemical products in the form of particles varying from powders to coarse lumps”. It is recommended that test samples should be taken in accordance w

10、ith BS5309-4 which is the basis for the ISO publication. 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 with a British Standard does not of itself confer immunity from leg

11、al obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment tabl

12、e on the inside front cover.BS7319-2:1990 BSI 12-1999 1 1 Scope and field of application This InternationalStandard specifies a method for the determination of the loss of mass at110 C (conventional moisture) of sodium chloride for industrial use. 2 Principle Drying in an oven at110 2 C to constant

13、mass. 3 Apparatus Ordinary laboratory apparatus and 3.1 Weighing bottle, squat type (approximate dimensions50mm in diameter and25mm high), with ground glass lid. 3.2 Electric oven, with natural draught, capable of being controlled at110 2 C. NOTECheck this temperature with a thermometer mounted so t

14、hat the bulb is in close proximity to the weighing bottle used during a test. 3.3 Desiccator, containing silica gel phosphorus pentoxide or a molecular sieve. 4 Sampling and samples For methods of sampling and the number of samples to be taken for a given quantity of product, the procedure specified

15、 in ISO. 1)shall be followed. 5 Procedure 5.1 Test portion Weigh, to the nearest1mg, about10g of the test sample in the weighing bottle(3.1), previously dried at110 2 C, cooled in the desiccator(3.3) and weighed to the nearest0,1mg. NOTEIf the loss in mass at110 C is lower than0,01% (m/m), correspon

16、ding to a difference in mass (m 1 m 2 ) of less than1mg, take a50g test portion and use a weighing bottle of such a size as to allow as thin a layer as possible to be obtained. 5.2 Determination Control the temperature of the oven(3.2) at110 2 C. In the oven place the weighing bottle containing the

17、test portion(5.1), its lid placed aslant, and a watch glass, the diameter of which is slightly larger than that of the weighing bottle. After drying the salt, replace the lid with the watch glass and place all in the desiccator(3.3). After cooling, close the weighing bottle with its lid and reweigh

18、to the nearest0,1mg. Repeat the above procedure several times until the mass remains constant, i.e.until two consecutive weighings carried out at an interval of about1h do not differ by more than0,2mg. 6 Expression of results 6.1 Method of calculation and formula The loss of mass at110 C, expressed

19、as a percentage by mass, is given by the formula: where m 0 is the mass, in grams, of the test portion; m 1 is the mass, in grams, of the weighing bottle containing the test portion, with lid, before drying; m 2 is the mass, in grams, of the weighing bottle containing the test portion, with lid, aft

20、er drying. 6.2 Repeatability and reproducibility Comparative analyses on two samples in nineteen laboratories have given the following statistical results: 7 Test report The test report shall include the following particulars: a) the reference of the method used; b) the results and the method of exp

21、ression used; c) any unusual features noted during the determination; d) any operation not included in this InternationalStandard, or regarded as optional. 1) In preparation. Evaporated salt Marine salt Mean (percentage by mass) 0,022 1,21 Standard deviation for repeatability ( r ) 0,002 0,04 for re

22、producibility ( R ) 0,007 0,15 m 1 m 2 () 100 m 0 - 2 blankBS7319-2:1990 BSI 12-1999 Publication(s) referred to Seenational foreword.BS7319-2: 1990 ISO2483:1973 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing Brit

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