1、BRITISH STANDARD BS7319-3: 1990 ISO2479:1972 Analysis of sodium chloride for industrial use Part3: Method for determination of matter insoluble in water or in acidBS7319-3:1990 This BritishStandard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished und
2、er the authorityof the 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 comment88/55616DC ISBN 0 580 18538 9 Committees responsible for this BritishStandard The preparation
3、of this BritishStandard 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 Deterg
4、ent Industry Association 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 Properietors Association Department of Trade and Industry (Laboratory of the Government Ch
5、emist) Food and Drink Federation Milk Marketing Board for Northern Ireland Royal Association of British Dairy Farmers Salt Manufacturers Association Amendments issued since publication Amd. No. Date CommentsBS7319-3:1990 BSI 12-1999 i Contents Page Committees responsible Inside front cover National
6、foreword ii 1 Scope 1 2 Field of application 1 3 Principle 1 4 Reagent 1 5 Apparatus 1 6 Sampling and samples 1 7 Procedure 1 8 Expression of results 2 9 SPECIAL CASE: Determination of insoluble matter in an acid medium 2 10 Test report 3 Publication(s) referred to Inside back coverBS7319-3:1990 ii
7、BSI 12-1999 National foreword BS7319 has been prepared under the direction of the Chemicals Standards Policy 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 f
8、or determination were previously published as appendices to BS998:1969. A list of the Parts of BS7319 is given in Part1. This Part of BS7319 is identical with ISO2479:1972 “Sodium chloride for industrial use Determination of matter insoluble in water or in acid and preparation of principal solutions
9、 for other determinations” published by the International Organization for Standardization (ISO). It supersedes Appendix G of BS998:1969, which is withdrawn. Additional information Reagents. With reference to clause4 and9.2, the reagents used should be of recognized analytical grade; water complying
10、 with grade3 of BS3978 is suitable. Apparatus. With reference to5.1, filter of grade designation P10 or P16 complying with BS1752 is suitable. Units relating to concentration. The units used in this standard are based on normality (N). The corresponding values, expressed as amounts of substance conc
11、entrations, are as follows. Sampling. With reference to clause6 and9.4, the method referred to has now been published as ISO8213:1986 “Chemical products for industrial use Sampling techniques Solid chemical products in the form of particles varying from powders to coarse lumps”. It is recommended th
12、at test samples should be taken in accordance with BS5309-4, which is the basis for the ISO publication. Calculation of result on a moisture free basis. The matter insoluble in water content, expressed in milligrams per kilogram on a moisture free basis, is calculated by multiplying the result obtai
13、ned in accordance with8.1 by where H is the moisture content in%(m/m) determined in accordance with BS7319-2. 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
14、 Standard does not of itself confer immunity from legal obligations. Clause As printed Expressed as amounts of substance concentrations 9.2.1 N c(HCl)=1mol/L 9.2.2 N c(NaOH)=1mol/L 10 6 100H - Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an
15、 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 table on the inside front cover.BS7319-3:1990 BSI 12-1999 1 1 Scope This International Standard specifies a method for determinin
16、g insoluble matter in sodium chloride for industrial use. It also describes the preparation of principal solutions for other determinations. NOTESodium chloride for industrial use may contain components that are only very slightly soluble or dissolve very slowly in water. Insoluble substances in sod
17、ium chloride for industrial use shall therefore be defined by the conditions of determination described in this International Standard. These conditions reproduce those normally used during the handling of salt for industrial use. The object is not to dissolve all the impurities but only those of in
18、terest to users. 2 Field of application 2.1 General case The method is applicable to the analysis of sodium chloride for industrial use, carried out in aqueous solution. 2.2 Special case Determination of insoluble matter in an acid medium. NOTEWhatever the conditions adopted, all related determinati
19、ons shall be carried out in the same medium, except the determination of chlorides which shall always be carried out in an aqueous solution. 3 Principle Solution of a test portion in water. Filtration, drying and weighing of the insoluble residue. Dilution of the filtrate to form the principal solut
20、ion (solution A) for carrying out other determinations. 4 Reagent Distilled water, or water of equivalent purity, shall be used in the test. 4.1 Silver nitrate,5g/l nitric solution. Dissolve0,5g of silver nitrate in a little water, add10ml of nitric acid solution 1,40g/ml approximately, and dilute t
21、o100ml. 5 Apparatus Ordinary laboratory apparatus and 5.1 Filter crucible or funnel, glass or porcelain, approximately30mm diameter and of a porosity grade P10 or P16 (pore size index416m). 5.2 Electric oven, ventilated by convection and capable of being controlled at110 2 C. 5.3 Desiccator, contain
22、ing silica gel, phosphorus pentoxide or a molecular sieve. 6 Sampling and samples For methods of sampling and the number of samples to be taken for a given quantity of product, the procedure described in ISO. 1)shall be followed. 7 Procedure 7.1 Test portion Weigh, to the nearest0,01g, approximately
23、100g of the test sample. 7.2 Determination Place the test portion(7.1) in a600ml beaker and add350ml of water. Heat at just below boiling for10min, with stirring, and then transfer the beaker, covered with a watch glass, to a boiling water bath for30min. Cool to approximately20 C. Filter by vacuum o
24、n the filter crucible(5.1), previously dried at110 C, cooled in the desiccator(5.3), and weighed to the nearest0,1mg. Then wash the insoluble matter, in groups of five successive washings, using20ml of water each time, disconnecting the vacuum after each washing in order to bring the insoluble matte
25、r into suspension for approximately1min before filtering, and checking for absence of chloride from the filtrate after the fifth, tenth or fifteenth washing10ml of the washing water shall remain clear5min after adding10ml of the nitric silver nitrate solution(4.1). Cease washing as soon as the check
26、 indicates absence of chlorides. Dry the crucible and its contents in the oven(5.2) controlled at110 2 C for1h, cool in the desiccator(5.3) and weigh to the nearest0,1mg. Repeat this operation until two weighings differ by not more than0,2mg. NOTEIf the insoluble matter is so finely divided as to cl
27、og the filter, repeat the determination and add, after the350ml of water,1,5g, weighed to the nearest0,1mg, of a filter aid (kieselguhr) of analytical quality. The minimum particle size of the filter aid should be15m and it should be dried, at about110 C, to constant mass before use. 1) In preparati
28、on.BS7319-3:1990 2 BSI 12-1999 7.3 Preparation of the principal solution for other determinations (solution A) Quantitatively transfer the filtrate obtained, after filtering and washing of the insoluble matter, to a1000ml one-mark volumetric flask. Dilute to the mark and mix. Keep this solution for
29、the other determinations. 8 Expression of results 8.1 Method of calculation and formula The matter insoluble in water is given, as a percentage by mass, by the formula: where m 0 is the mass, in grams, of the test portion; m 1 is the mass, in grams, of the filter crucible and insoluble matter; m 2 i
30、s the mass, in grams, of the filter crucible alone. NOTEIf a filter aid has been used, deduct its mass from m 1(seeNote in7.2). 8.2 Repeatability and reproducibility Comparative analyses on two samples in nineteen laboratories have given the following statistical results: 9 SPECIAL CASE: Determinati
31、on of insoluble matter in an acid medium 9.1 Principle Solution of a test portion in an acid medium. Filtration, drying and weighing of the insoluble residue. Dilution of the filtrate to form the principal solution (solution B) for carrying out other determinations, except the determination of chlor
32、ides. 9.2 Reagents In addition to water use: 9.2.1 Hydrochloric acid, N standard volumetric solution. 9.2.2 Sodium hydroxide, N standard volumetric solution. 9.2.3 Methyl orange,0,5g/l solution. 9.3 Apparatus See section5. 9.4 Sampling and samples See section6. 9.5 Procedure 9.5.1 Test portion Weigh
33、, to the nearest0,01g, two test portions of100 0,1g from the test sample. 9.5.2 Determination of total alkalinity Place the first test portion(9.5.1) into a600ml beaker. Add300ml of water and50,00ml of the hydrochloric acid standard volumetric solution(9.2.1). Bring to the boil, maintain boiling for
34、 about10min and cool to approximately20 C. Transfer quantitatively to a500ml one-mark volumetric flask, dilute to the mark and mix. Filter slightly more than100ml of the solution through a fluted filter paper of a fine grade and reject the first portions of the filtrate. Pipette100ml of filtrate int
35、o a250ml conical flask. Add3 drops of methyl orange standard volumetric solution(9.2.3) and back-titrate with the sodium hydroxide solution(9.2.2) to the colour change from red to yellow. Record the volume, V, of sodium hydroxide solution used. 9.5.3 Determination Place the second test portion(9.5.1
36、) into a600ml beaker. Add300ml of water,(505V + x)ml 2)of the hydrochloric acid standard volumetric solution(9.2.1) and dilute to approximately350ml. Proceed as described in clause7.2, starting at the second sentence: “Heat at just below boiling for10min.” 9.5.4 Preparation of principal solution for
37、 the determinations (solution B) Proceed as described in7.3, but using the acid filtrate. Evaporated salt Marine salt Mean (percentage by mass) 0,001 0,044 Standard deviation for repeatability ( r ) 0,0005 0,002 for reproducibility ( R ) 0,0008 0,008 m 1 m 2 () 100 m 0 - 2) The value of x is to be t
38、he subject of agreement between the interested parties.BS7319-3:1990 BSI 12-1999 3 9.6 Expression of results Matter insoluble in the acidic medium is given, as a percentage by mass, by the formula in8.1. 10 Test report The test report shall include the following particulars: a) the reference of the
39、method used; b) the results and the method of expression used; c) any unusual features noted during the determination; d) any operation not included in this International Standard or regarded as optional.4 blankBS7319-3:1990 BSI 12-1999 Publication(s) referred to See national foreword.BS7319-3: 1990
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