1、BRITISH STANDARD BS 4140-18: 1986 ISO 2829:1973 Methods of test for Aluminium oxide Part 18: Determination of phosphorus content ISO title: Aluminium oxide primarily used for the production of aluminium Determination of phosphorus content Reduced phosphomolybdate spectrophotometric method NOTEIt is
2、recommended that this Part be read in conjunction with the general information giveninBS4140-0 “General introduction” which is issued separately. UDC 661.862.22:546.18:543.42BS4140-18:1986 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was publis
3、hed under the authorityofthe Executive Boardand comes into effect on 28February1986 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/24 Draft for comment 85/52367 DC ISBN 0 580 15015 1 Amendments issued since publication Amd. No. Date of issue Com
4、mentsBS4140-18:1986 BSI 10-1999 i Contents Page National foreword ii 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagents 1 5 Apparatus 2 6 Procedure 2 7 Expression of results 3 8 Test report 3 Publication referred to Inside back coverBS4140-18:1986 ii BSI 10-1999 National forew
5、ord This Part of BS4140 is identical with ISO2829:1973 “Aluminium oxide primarily used for the production of aluminium Determination of phosphorus content Reduced phosphomolybdate spectrophotometric method”, published by the International Organization for Standardization (ISO). The method supersedes
6、 clause18 of Addendum No.3 (1974) to BS4140:1967. Parts17 to19 of this standard collectively supersede Addendum No.3 (1974) to BS4140:1967 which is withdrawn. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard witho
7、ut deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal m
8、arker. In British Standards it is current practice to use the symbol “L” for litre (and its submultiples) rather than “l”. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. This standard prescribes methods of test only, and sho
9、uld not be used or quoted as a specification defining limits of purity. Reference to this Part should indicate that the method of test used complies with BS4140-18:1986. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsi
10、ble for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-reference International Standard Corresponding British Standard ISO/R 804:1968 (Revised as ISO804:1976) BS 4140 Methods of test for aluminium oxide Part 4:1986 Prepa
11、ration of sample solution by alkaline fusion (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 incorporated. Th
12、is will be indicated in the amendment table on the inside front cover.BS4140-18:1986 BSI 10-1999 1 1 Scope and field of application This International Standard specifies a spectrophotometric method using reduced ammonium phosphomolybdate for the determination of the phosphorus content of aluminium o
13、xide primarily used for the production of aluminium. The method is applicable to phosphorus contents, expressed as P 2 O 5 , greater than0,0005%. 2 Reference ISO/R 804, Aluminium oxide primarily used for the production of aluminium Preparation of sample solution for analysis. 3 Principle Preparation
14、 of a solution from a test portion by alkaline fusion, either with a mixture of sodium carbonate and boric acid, or with a mixture of sodium carbonate and sodium tetraborate. Dissolution of the melt in nitric acid and adjustment of an appropriate aliquot portion to pH2. Formation of the phosphomolyb
15、dic complex and extraction by 2-methylpropan-1-ol in a sulphuric acid medium. Reduction of the complex by tin(II) chloride in the organic phase and spectrophotometric measurement of the reduced complex contained in the organic phase at a wavelength of about730nm. 4 Reagents Distilled water, or water
16、 of equivalent purity, shall be used in the test. 4.1 Sodium carbonate, anhydrous. 4.2 Boric acid (H 3 BO 3 ), or alternatively 4.2.1 Sodium tetraborate, anhydrous (Na 2 B 4 O 7 ). 4.3 2-Methylpropan-1-ol (isobutyl alcohol), approximately0,805g/ml. 4.4 Nitric acid, approximately8N solution. Dilute54
17、0ml of nitric acid solution, approximately1,40g/ml, about68% (m/m) solution, with water to1000ml. 4.5 Sulphuric acid, approximately10N solution. Carefully add, in small portions,280ml of sulphuric acid, approximately1,84g/ml, about96% (m/m) solution, to about500ml of water and, after cooling, dilute
18、 to1000ml. 4.6 Sulphuric acid, approximately N solution. Take100ml of the sulphuric acid solution (4.5) and dilute with water to1000ml. 4.7 Sulphuric acid, approximately0,5N solution. Take250ml of the sulphuric acid solution (4.6) and dilute with water to500ml. 4.8 Ammonium acetate, 500g/l solution.
19、 4.9 Iron(III) sulphate, acid solution. Dissolve0,5g of iron(III) sulphate nonahydrate Fe 2 (SO 4 ) 3 .9H 2 O in50ml of water containing2mlof perchloric acid solution, approximately1,60g/ml, about64,5% (m/m) solution, and dilute to100ml. 1 ml of this solution contains about0,001g of Fe(III). NOTEIf
20、iron(III) sulphate nonahydrate of recognized analytical reagent quality is not available, ammonium iron(III) sulphate dodecahydrate may be used. In this case, to obtain a solution with the same concentration of iron(III), dissolve, instead of0,5g of iron(III) sulphate nonahydrate,0,86g of ammonium i
21、ron(III) sulphate dodecahydrate FeNH 4 (SO 4 ) 2 .12H 2 O. 4.10 Ammonium iron(II) sulphate, acid solution. Dissolve0,5g of ammonium iron(II) sulphate hexahydrate Fe(NH 4 ) 2 (SO 4 ) 2 .6H 2 O in50ml of water containing0,5ml of perchloric acid solution, approximately1,60g/ml, about64,5% (m/m) solutio
22、n, and dilute to100ml. 1 ml of this solution contains about0,0007g of Fe(II). Prepare this solution just before use. 4.11 Ammonium molybdate, 25g/l acid solution. Dissolve5g of ammonium molybdate tetrahydrate (NH 4 ) 6 Mo 7 O 24 .4H 2 O in water at60 C. Cool and dilute to100ml. Add to the solution10
23、0ml of the sulphuric acid solution (4.5) and mix. Store the solution in a plastics bottle. 4.12 Washing solution Saturate, at ambient temperature, approximately500ml of the sulphuric acid solution(4.7) with the2-methylpropan-1-ol (4.3). 4.13 Tin(II) chloride, 2,38g/l hydrochloric solution. Dissolve1
24、,19g of tin(II) chloride dihydrate (SnCl 2 .2H 2 O) in85ml of hydrochloric acid solution, approximately1,19g/ml, about38% (m/m) solution, dilute to500ml and transfer the solution into a plastics bottle. Prepare this solution just before use. 4.14 Phosphorus standard solution corresponding to0,400g o
25、fP 2 O 5per litre. Weigh, to the nearest0,0001g, 0,7668g of anhydrous potassium dihydrogen phosphate (KH 2 PO 4 ), previously dried over about12N sulphuric acid. Dissolve in water, quantitatively transfer the solution into a1000ml one-mark volumetric flask, dilute to the mark and mix.BS4140-18:1986
26、2 BSI 10-1999 1 ml of this standard solution contains0,4mg of P 2 O 5 . 4.15 Phosphorus standard solution corresponding to0,010g of P 2 O 5per litre. Place25,0ml of the standard phosphorus solution(4.14) in a1000ml one-mark volumetric flask, dilute to the mark and mix. 1ml of this standard solution
27、contains0,01mg ofP 2 O 5 . 4.16 Phosphorus standard solution corresponding to0,0010g of P 2 O 5per litre. Place25,0ml of the standard phosphorus solution(4.15) in a250ml one-mark volumetric flask, dilute to the mark and mix. 1ml of this standard solution contains0,001mg of P 2 O 5 . 5 Apparatus Ordi
28、nary laboratory apparatus and 5.1 Apparatus specified in ISO/R804 5.2 Burette, graduated in0,05ml divisions (seeISO/R385). 5.3 Separating funnels, 200ml, with ground glass stoppers. 5.4 pH meter, fitted with a glass electrode. 5.5 Spectrophotometer NOTEAll glassware, including the reagent bottles, s
29、hall be of borosilicate or other quality of glass unaffected by phosphorus. Alternatively, plastics apparatus may be used. Wash all the glassware carefully with about6N hydrochloric acid solution, then rinse thoroughly with water. 6 Procedure 6.1 Preparation of the test solution (principal solution
30、P). Using the apparatus specified in5.1, follow the instructions given in clauses5.1, 5.2 and5.3 of ISO/R804, to give a volume of250ml of principal solution P. 6.2 Blank test At the same time as the determination, carry out a blank test in the absence of the pure aluminium oxide, according to the in
31、structions of clause5.4.2 of ISO/R804. Then proceed using the same quantities of all reagents used for the determination and following the same procedure. 6.3 Preparation of the calibration curve 6.3.1 Preparation of standard colorimetric solutions, referring to spectrophotometric measurements made
32、with an optical path length of1cm. 6.3.1.1 TAKING ALIQUOT PORTIONS OF THE STANDARD SOLUTION Into a series of six of the separating funnels (5.3) measure, by means of the burette (5.2), the volumes of the standard phosphorus solution (4.16) shown in the following table: Add to each separating funnel
33、the quantity of water required to increase the volume to60ml, then add1ml of the iron(III) sulphate solution (4.9) and1ml of the ammonium iron(II) sulphate solution (4.10) to each funnel and mix. 6.3.1.2 FORMATION OF THE OXIDIZED PHOSPHOMOLYBDATE COMPLEX AND EXTRACTION OF THE REDUCED COMPLEX Add to
34、each separating funnel3ml of the sulphuric acid solution (4.6), then7,5ml of the ammonium molybdate solution (4.11), mix and leave to stand for10min. Add25ml of the2-methylpropan-1-ol(4.3) and shake vigorously for1min. Allow the layers to separate, run off the aqueous phase and discard it. To the or
35、ganic phase add30ml of the washing solution (4.12), shake for1min, run off the aqueous phase and discard it. Repeat this washing once more. Then add30ml of the sulphuric acid solution (4.6) and0,5ml of the tin(II) chloride solution (4.13), shake for30s, allow to settle, run off the aqueous phase and
36、 discard it. Transfer the organic phase to a25ml one-mark volumetric flask which has been previously dried. Wash the separating funnel with1 to2ml of the2-methylpropan-1-ol (4.3), transferring the washings to the same volumetric flask. Then dilute to the mark with the same 2-methylpropan-1-ol(4.3).
37、Mix and leave to stand, shielded from light, for at least10min. Standard phosphorus solution (4.16) Corresponding mass of P 2 O 5 ml mg 0 a 0 5,0 0,005 10,0 0,010 15,0 0,015 20,0 0,020 25,0 0,025 a Compensation solution.BS4140-18:1986 BSI 10-1999 3 6.3.2 Spectrophotometric measurements After allowin
38、g to stand for at least10min but not more than60min, carry out the spectrophotometric measurements using the spectrophotometer (5.5) at a wavelength of about730nm after having adjusted the instrument to zero absorbance against the compensation solution. 6.3.3 Preparation of the calibration chart Plo
39、t a graph having, for example, the values, expressed in milligrams, of the masses of P 2 O 5per25ml of the standard colorimetric solutions on the abscissae and the corresponding values of absorbance on the ordinates. 6.4 Determination 6.4.1 Treatment of the test solution Take a volume of the test so
40、lution (6.1) containing a mass of phosphorus corresponding to0,015 to0,025mg ofP 2 O 5 . Adjust the pH to2 0,1by the addition, in small portions, of the ammonium acetate solution (4.8), checking by means of the pH meter (5.4). Transfer the solution quantitatively to one of the separating funnels (5.
41、3). Increase the volume of the solution to about60ml and then add1ml of the iron(III) sulphate solution(4.9),1ml of the ammonium iron(II) sulphate solution (4.10) and mix. 6.4.2 Formation of the oxidized phosphomolybdic complex and extraction of the reduced complex Follow the instructions in6.3.1.2.
42、 6.4.3 Spectrophotometric measurements Carry out the spectrophotometric measurements on the organic phase resulting from the test solution and on that originating from the blank test solution, according to the instructions in6.3.2, after having adjusted the spectrophotometer (5.5) to zero absorbance
43、 against the 2-methylpropan-1-ol (4.3). 7 Expression of results By means of the calibration chart (6.3.3), determine the mass of P 2 O 5corresponding to the absorbance values. The phosphorus pentoxide content (P 2 O 5 ) is given, as a percentage by mass, by the formula where 8 Test report The test r
44、eport shall include the following particulars: a) the reference of the 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 the document to which reference is made, or re
45、garded as optional. m 0 is the mass, in grams, of the test portion used for the preparation of the principal solutionP; m 1 is the mass, in milligrams, of P 2 O 5found in the aliquot portion of the test solution; m 2 is the mass, in milligrams, of P 2 O 5found in a corresponding aliquot portion of t
46、he blank test solution; D is the ratio of the volume of the principal solution P to the volume of the aliquot portion of this solution taken for the determination. m 1 m 2 ()D 100 1 000m 0 - m 1 m 2 ()D 10m 0 - =4 blankBS4140-18:1986 BSI 10-1999 Publication referred to See national foreword.BS 4140-
47、18: 1986 ISO 2829:1973 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revision
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