1、BRITISH STANDARD BS 5050-8: 1980 ISO 3391:1976 Methods of Test for cryolite Part 8: Determination of calcium content ISO title: Cryolite, natural and artificial Determination of calcium content Flame atomic absorption method UDC 661.862.369:546.41:543.422BS5050-8:1980 This British Standard, having b
2、een prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Executive Board and comesinto effect on 31 December 1980 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIC/24 Draft for comment 74/54499 D
3、C ISBN 0 580 11449 X Cooperating organizations The Chemicals Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Fatty Acid Distillers British
4、Tar Industry Association Chemical Industries Association* Consumer Standards Advisory Committee of BSI Department of Health and Social Security Department of Industry (Laboratory of the Government Chemist) Fertiliser Manufacturers Association Ltd. Hydrocarbon Solvents Association Ministry of Agricul
5、ture, Fisheries and Food Ministry of Defence National Sulphuric Acid Association Paintmakers Association of Great Britain Ltd. Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association Standardization of Tar Products Tests Committee Chemical Society, Analytical Division* T
6、he organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Aluminium Federation British Ceramic Research Association Royal Institute of Chemistry Amendments issued since
7、publication Amd. No. Date of issue CommentsBS5050-8:1980 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Procedure 1 7 Expression of results 3 8 Test report 3 Pub
8、lications referred to Inside back coverBS5050-8:1980 ii BSI 12-1999 National foreword This British Standard has been prepared under the direction of the Chemicals Standards Committee in order to provide methods for the analysis of cryolite for industrial use. For some years the UnitedKingdom has par
9、ticipated in the work of preparing methods of test applicable to this material, organized by Sub-committee7 (formerly WG8), Alumina and related compounds, of Technical Committee47, Chemistry, of the International Organization for Standardization (ISO). As international agreement is reached on the me
10、thods, it is proposed to publish them as Parts of this BritishStandard. This Part of BS5050 is identical with ISO3391 “Cryolite, natural and artificial Determination of calcium content Flame atomic absorption method”. Terminology and conventions. The text of the International Standard has been appro
11、ved as suitable for publication, without deviation, as a BritishStandard. Some terminology and certain conventions are not identical with those used in BritishStandards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In British Standards, it i
12、s current practice to use a full point on the baseline as the decimal marker. Where the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Cross-references There is at present no British Standard identical with ISO1619:1976, but clause2.3 of
13、 BS5050:1974 “Methods of test for cryolite”, covers the same ground as clause3.3 of ISO1619 (referred to in clause6.1 of this standard). The other International Standards listed in the annex are for information only. Corresponding British Standards are listed below. International Standard Correspond
14、ing British Standard BS 5050:1974 Methods of test for cryolite Title ISO 1620:1976 Clause 3 Determination of silica content (Related) ISO 1693:1976 Clause 4 Determination of fluorine content (Related) ISO 1694:1976 Clause 5 Determination of iron content (Related) ISO 2366:1974 Clause 6 Determination
15、 of sodium content (Related) ISO 2367:1972 Clause 7 Determination of aluminium content (gravimetric method) (Related) ISO 2830:1973 Clause 8 Determination of aluminium content (atomic absorption method) (Related) BS 5050 Methods of tests forcryolite ISO 3392:1976 Part 9:1980 Determination of water c
16、ontent (Karl Fischer method) (Identical) ISO 3393:1976 Part 10:1980 Gravimetric determination of moisture content (Identical)BS5050-8:1980 BSI 12-1999 iii The first seven international test methods in the cryolite series were published in combined form as BS5050:1974 and were modified both to take i
17、nto account UnitedKingdom comments made during their development and to conform with BSI layout. In accordance with current policy the remaining standards are to be published, without alteration, as separate dual numbered (BSI/ISO) Parts of this British Standard. In order to establish a uniform and
18、acceptable overall layout, it is intended, in conjunction, to revise the1974 edition, progressively replacing it by the corresponding International Standards which will also be published, without alteration, as separate Parts of this British Standard. The change will be made, for each Part, immediat
19、ely following the routine five-yearly review of the International Standard concerned. This will ensure that the revised standard satisfies current requirements and will allow the UnitedKingdom to propose changes if the International Standards are not completely acceptable as they stand. It is expect
20、ed, however, that such changes will be minimal. When the process of revision has been completed, the1974 edition will be withdrawn. Additional information Water. Water complying with the requirements of clause4 is specified inBS3978:1966 “Water for laboratory use”. Hydrochloric acid, approximately1.
21、18g/ml, about36% (m/m) solution, which is the corresponding reagent normally obtainable in the UnitedKingdom, is suitable for use in place of the approximately1.19g/ml solution specified in4.2. Clause 4.5. The identity of the hydrochloric acid specified in line3 has been omitted. Line3 should read “
22、50,0ml of the hydrochloric acid solution (4.2), diluted (1+1)”. Clause 6.3.1, 6.4.1. The evaporations described in6.3.1, paragraph2 and6.4.1, paragraph1, should be carried out in an efficient fume cupboard. WARNING. Perchloric acid, specified as an alternative reagent in the note to6.3.1, is toxic,
23、severely corrosive and may cause fire in contact with combustible materials. Prevent contact with eyes, skin, clothing and other combustible material. Carry out all operations involving its use in an efficient fume cupboard. Users of perchloric acid are advised to consult appropriate literature for
24、more detailed recommendations. This standard prescribes methods of test only, and should not be used or quoted as a specification defining limits of purity. References to the standard should state that the methods of test used comply with the requirements of BS5050. A British Standard does not purpo
25、rt 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 legal obligations. International Standard BS 5050 Methods of tests forcryolite Title ISO 4280
26、:1977 Part 11:1980 Determination of sulphate content (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated.
27、 This will be indicated in the amendment table on the inside front cover.iv blankBS5050-8:1980 BSI 12-1999 1 1 Scope and field of application This International Standard specifies a flame atomic absorption method for the determination of the calcium content of natural and artificial cryolite. 2 Refe
28、rence ISO 1619, Cryolite natural and artificial Preparation and storage of test samples. 3 Principle Dissolution of a test portion in concentrated sulphuric acid and treatment with concentrated hydrochloric acid. Aspiration of the solution into an acetylene dinitrogen monoxide flame. Determination o
29、f calcium content by spectrophotometric measurement of the absorption of the422,7nm line emitted by a calcium hollow cathode lamp. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Sulphuric acid, approximatel
30、y1,84g/ml, about96% (m/m) solution. 4.2 Hydrochloric acid, approximately1,19g/ml, about38% (m/m) solution. 4.3 Complexant Either. 4.3.1 Lanthanum nitrate, 310g/l solution. Weigh, to the nearest 0,1g, 31,0g of lanthanum nitrate hexahydrate La(NO 3 ) 2 .6H 2 O and place a100ml one-mark volumetric flas
31、k. Dissolve in water dilute to the mark and mix. NOTEIt is possible to use lanthanum chloride heptahydrate (LaCl 3 .7H 2 O),270g/l solution. Or 4.3.2 Triethanolamine, dilute solution. Dilute 100ml of triethanolamine (CH 2 OHCH 2 ) 3 N to200ml with water. 4.4 Sodium chloride solution, corresponding t
32、o16,0g of Na per litre. Weigh, to the nearest 0,001g, 4,067g of sodium chloride, previously dried for12h at approximately120 C and cooled in a desiccator, into a100ml one-mark volumetric flask. Dissolve in water, dilute to the mark and mix. 4.5 Aluminium, acid solution corresponding to6,6g of Al per
33、 litre. Weigh, to the nearest 0,001g,0,66g of extra pure aluminium in the form of small shavings, and dissolve in50,0ml of hydrochloric acid solution, diluted1+1 (V + V), in a porcelain dish. Transfer the solution quantitatively to a100ml one-mark volumetric flask, cool, dilute to the mark and mix.
34、4.6 Calcium, standard solution, corresponding to1,00g of Ca per litre. Weigh, to the nearest0,0001g, 2,4972g of calcium carbonate, previously dried for2h at approximately110 C and cooled in a desiccator. Transfer to a250ml beaker and dissolve with care in12ml of the hydrochloric acid solution (4.2),
35、 previously diluted with12ml of water. Transfer the solution quantitatively to a1000ml one-mark volumetric flask, cool, dilute to the mark and mix. Transfer to a flask of material free from calcium. 1 ml of this standard solution contains 1,00mg of Ca. 4.7 Calcium, standard solution, corresponding t
36、o0,10g of Ca per litre. Place 100,0ml of the standard calcium solution (4.6) in a1000ml one-mark volumetric flask, dilute to the mark and mix. Transfer to a flask of material free from calcium. 1 ml of this standard solution contains 0,10mg of Ca. 5 Apparatus Ordinary laboratory apparatus and: 5.1 P
37、latinum dishes, diameter about 75mm, height about30mm. 5.2 Atomic absorption spectrophotometer, fitted with a burner fed from cylinders of dinitrogen monoxide and acetylene (a50/60mm burner is suitable). 5.3 Calcium hollow cathode lamp 6 Procedure 6.1 Test portion Weigh, to the nearest 0,0001g,0,500
38、g of the dried test sample, prepared by the procedure specified in3.3 ofISO1619. 6.2 Blank test Carry out a blank test at the same time as the determination, following the same procedure and using the same quantities of all the reagents used for the determination. Before introducing the sulphuric ac
39、id, add10,0ml of the aluminium solution (4.5) and10,0ml of the sodium chloride solution (4.4).BS5050-8:1980 2 BSI 12-1999 6.3 Preparation of calibration graph 6.3.1 Preparation of the standard matching solutions Into a series of six of the platinum dishes (5.1), place the quantities of the standard
40、calcium solution (4.7) indicated in the following table. Add to each dish 10,0ml of the acid aluminium solution (4.5),10,0ml of the sodium chloride solution (4.4) and5,0ml of the sulphuric acid solution (4.1). Warm with care on a sand bath or hot-plate to evaporate the free sulphuric acid. NOTEThe 5
41、,0ml of the sulphuric acid solution (4.1) can be replaced by10,0ml of perchloric acid solution ( approximately1,70g/ml). In this case the spectrophotometric measurements are carried out using an air-acetylene flame (clear, non-luminous, oxidizing flame). Introduce into each dish 1,0ml of the hydroch
42、loric acid solution (4.2) and30ml of water. Transfer the contents quantitatively to100ml one-mark volumetric flasks, add either10ml of the lanthanum nitrate or chloride solution (4.3.1) or20ml of the triethanolamine solution (4.3.2) and, after cooling, dilute to the mark and mix. Store these solutio
43、ns in flasks of material free from calcium. 6.3.2 Spectrophotometric measurements Mount the calcium hollow cathode lamp (5.3). Switch on the apparatus (5.2)a sufficient time in advance for it to reach stabilization. Adjust the wavelength to422,7nm and the sensitivity and the aperture of the slit acc
44、ording to the characteristics of the apparatus. Adjust the gas pressures according to the characteristics of the burner so as to obtain an oxidizing flame. Control the rate of aspiration (for example, to2 to3ml/min). Aspirate the standard matching solutions (6.3.1) in the flame and measure the absor
45、bance of each. Take care to maintain the quantity of solution aspirated in the flame constant with respect to time during all the measurements. Spray water through the burner after each measurement. 6.3.3 Plotting of the calibration graph Plot a graph having, for example, the masses, expressed as mi
46、lligrams of Ca in100ml of the standard matching solutions as abscissae and the corresponding values of absorbance, decreased by the value for the reagent blank for the calibration graph, as ordinates. 6.4 Determination 6.4.1 Preparation of the test solution Place the test portion (6.1) in one of the
47、 platinum dishes (5.1) and add5,0ml of the sulphuric acid solution (4.1) (seenote to6.3.1). Warm with care on a sand bath or hot-plate until the hydrofluoric acid has evaporated (15to20min). Allow the temperature to rise until the free sulphuric acid has evaporated. Introduce into the dish3,0ml of t
48、he hydrochloric acid solution (4.2) and30ml of water and warm on a boiling water bath until completely dissolved. Transfer the solution quantitatively to a100ml one-mark volumetric flask and add either10ml of the lanthanum nitrate or chloride solution (4.3.1) or20ml of the triethanolamine solution (
49、4.3.2). After cooling, dilute to the mark and mix. Store the solution in a flask of material free from calcium. 6.4.2 Spectrophotometric measurements 6.4.2.1 PRELIMINARY MEASUREMENT Carry out a preliminary measurement on the test solution (6.4.1) and on the blank solution (6.2) at the same time as the spectrophotometric measurements on the standard matching solutions (6.3.1) following the procedure specified in6.3.2. 6.4.2.2 BRACKETING MEASUREMENT Carry out a second measurement on the test solution (6.4.1) by bracketing between two standard matching solu
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