1、BRITISH STANDARD BS 5072-5: 1980 ISO 3429:1976 Methods of test for Sodium fluoride for industrial use Part 5: Determination of iron content ISO title: Sodium fluoride primarily used for the production ofaluminium Determination of iron content 1,10-phenanthroline photometric method UDC 661.833.361:54
2、6.33161:543.42.062:546.72BS5072-5:1980 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Executive Board and comesinto effect on 30April1980 BSI 12-1999 The following BSI references relate to the work on this
3、standard: Committee reference CIC/24 Draft for comment 74/54500 DC ISBN 0580 11216 0 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 industr
4、ial organizations: Association of Fatty Acid Distillers British Tar Industry Association Chemical Industries Association* Chemical Society, Analytical Division* Consumer Standards Advisory Committee of BSI Department of Health and Social Security Department of Industry (Laboratory of the Government
5、Chemist) Fertiliser Manufacturers Association Ltd Hydrocarbon Solvents Association Ministry of Agriculture, 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
6、 Association Standardization of Tar Products Tests Committee The 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 Ass
7、ociation Royal Institute of Chemistry Amendments issued since publication Amd. No. Date of issue CommentsBS5072-5:1980 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
8、 1 6 Procedure 2 7 Expression of results 3 8 Notes on procedure 3 9 Test report 3 Annex ISO Publications relating to sodium fluoride for industrial use and sodium fluoride primarily used for the production of aluminium 4 Publications referred to Inside back coverBS5072-5:1980 ii BSI 12-1999 National
9、 foreword WARNING NOTE. Sodium fluoride is toxic and is irritant, particularly in the form of dust. Carry out operations involving its use in a fume cupboard and wear suitable protective clothing to prevent inhalation of the dust and contact with the eyes, skin and clothing. This British Standard ha
10、s been prepared under the direction of the Chemicals Standards Committee in order to provide methods for the analysis of sodium fluoride for industrial use. For some years the United Kingdom has participated in the work of preparing methods of test applicable to this material, organized by Subcommit
11、tee 7 (formerly WG 8), Aluminium oxide and related compounds, of Technical Committee47, Chemistry, of the International Organization for Standardization (ISO). As international agreement is reached on the methods, it is proposed to publish them as Parts of this British Standard. This Part is identic
12、al with ISO 3429 “Sodium fluoride primarily used for the production of aluminium Determination of iron content 1, 10-phenanthroline photometric method”. Terminology and conventions. The text of the International Standard has been approved as suitable for publication, without deviation, as a British
13、Standard. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the de
14、cimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Related British Standards for ISO 2831 1) , ISO 2832 1)and ISO 2833 1)are BS5072-1, BS 5072-2 and BS 5072-3 respectively. NOTEThe title and clause1 of ISO 3429, IS
15、O 3430, ISO 3431, ISO 3566 and ISO 4278 (seetheAnnex) state that the sodium fluoride is “primarily used for the production of aluminium”. This is incorrect, at least for the UnitedKingdom. This has been brought to the attention of ISO Technical Committee47, in a proposal to amend the International S
16、tandards concerned. Cross-references International Standard Corresponding British Standard BS 5072 Methods of test for sodium fluoride for industrial use ISO 3428:1976 Part 4:1980 Preparation and storage of test samples (Identical) ISO 3430:1976 1) Part 6:1980 Determination of silica content (Identi
17、cal) ISO 3431:1976 1) Part 7:1980 Determination of soluble sulphates content (Identical) ISO 3566:1976 1) Part 8:1980 Determination of chlorides content (Identical) ISO 4278:1977 1) Part 9:1980 Determination of carbonate content (Identical) 1) Referred to in theAnnex, for information only.BS5072-5:1
18、980 BSI 12-1999 iii Additional information Water. Water complying with the requirements of clause4 is specified in BS3978 “Water for laboratory use”. Hydrochloric acid, approximately1.18g/ml, about36% (m/m) solution, which is the corresponding reagent normally obtainable in the UnitedKingdom, is sui
19、table for use in place of the approximately1.19g/ml solution specified in4.4 and 4.10.2. Nitric acid, approximately 1.42g/ml, about70% (m/m) solution, which is the corresponding reagent normally obtainable in the UnitedKingdom, is suitable for use in place of the approximately1.40g/ml solution speci
20、fied in4.3. Ethanol. The ethanol used in this determination may be replaced for these purposes by industrial methylated spirits66 degrees O.P., complying with the requirements of BS3591. It should be noted that the use of industrial methylated spirits is governed by The Methylated Spirits Regulation
21、s1952 (S.I. 1952 No2230). It is not permissible to use duty-free ethanol, received under the provisions of the Customs and Excise Act, 1952, Section III, for purposes for which industrial methylated spirits is an acceptable alternative to ethanol. This standard prescribes methods of test only, and s
22、hould not be used or quoted as a specification defining limits of purity. Reference to the standard should indicate that the methods of test used comply with the requirements of BS5072-5. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Stan
23、dards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. 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 standa
24、rd 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.iv blankBS5072-5:1980 BSI 12-1999 1 1 Scope and field of application This International Standard specifies a photometric method, using1,10-phenan
25、throline, for the determination of the iron content of sodium fluoride primarily used for the production of aluminium. The method is applicable to the determination of iron contents, expressed as Fe 2 O 3 , greater than0,020% (m/m). 2 Reference ISO 3428, Sodium fluoride for industrial use Preparatio
26、n and storage of test samples. 3 Principle Dissolution of a test portion by alkaline fusion. Preliminary reduction of iron(III) by means of hydroxylammonium chloride. Formation of the iron(II)-1,10-phenanthroline complex, in a buffered medium (pH value between3,5 and4,2). Photometric measurement of
27、the coloured complex at a wavelength of about510nm. 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only distilled water or water of equivalent purity. 4.1 Sodium carbonate, anhydrous. 4.2 Boric acid (H 3BO 3 ) 4.3 Nitric acid, approximately8N solution. Dilute54
28、0ml of nitric acid, approximately 1,40g/ml, about68% (m/m) solution, with water, dilute to 1000ml and mix. 4.4 Hydrochloric acid, approximately6N solution. Dilute 515ml of hydrochloric acid, approximately1,19g/ml, about38% (m/m) solution, with water, dilute to1000ml and mix. 4.5 Hydroxylammonium chl
29、oride,10g/l solution. Dissolve1g of hydroxylammonium chloride (NH 2 OH.HCl) in water, dilute to100ml and mix. 4.6 1,10-phenanthroline hydrochloride, 2,5g/l solution. Dissolve2,5g of1,10-phenanthroline hydrochloride monohydrate (C 12 H 8 N 2 .HCl.H 2 O) in water, dilute to1000ml and mix. NOTE1,10-phe
30、nanthroline hydrochloride monohydrate can be replaced by1,10-phenanthroline monohydrate. If this product is used, it should be dissolved an10ml of ethanol,95% (V/V), before adding water. 4.7 Buffer solution, pH4,9. Dissolve272g of sodium acetate trihydrate (CH 3 COONa.3H 2 O) in approximately500ml o
31、f water. Add240ml of glacial acetic acid, approximately1,05g/ml, about17,4N, dilute to1000ml and mix. 4.8 Sodium acetate trihydrate,500g/l solution. Dissolve50g of sodium acetate trihydrate in water, dilute to100ml and mix. 4.9 Acetic acid, dilute solution. Dilute500ml of glacial acetic acid, approx
32、imately1,05g/ml, about17,4N, with water, dilute to 1000mland mix. 4.10 Iron, standard solution, corresponding to0,200g of Fe 2 O 3per litre. This solution can be prepared by either of the two following methods: 4.10.1 Weigh, to the nearest 0,001g, 0,982g of ammonium iron(II) sulphate hexahydrate, (N
33、H 4 ) 2 Fe(SO 4 ) 2 .6H 2 O), place in a beaker of suitable capacity (100ml, for example) and dissolve in water. Add 20ml of sulphuric acid solution, approximately 1,84g/ml, about 96% (m/m) solution, transfer quantitatively to a1000ml one-mark volumetric flask, dilute to the mark and mix. 4.10.2 Wei
34、gh, to the nearest0,001g, 0,200g of iron(III) oxide (Fe 2 O 3 ) previously heated at600 C and cooled in a desiccator. Transfer to a beaker ofsuitable capacity (100ml, for example), add10mlofhydrochloric acid solution, approximately1,19g/ml, about38% (m/m) solution, and heat gently to dissolve. Allow
35、 to cool, transfer quantitatively to a1000ml one-mark volumetric flask, dilute to the mark and mix. 1ml of this standard solution contains0,200mg of Fe 2 O 3 . 4.11 Iron, standard solution, corresponding to0,010g of Fe 2 O 3per litre. Transfer 50,0ml of the standard solution (4.10) to a1000ml one-ma
36、rk volumetric flask, dilute to the mark and mix. 1ml of this standard solution contains 0,010mg of Fe 2 O 3 . Prepare this solution just before use. 4.12 Indicator paper, covering the pH range3,5to4,2 at intervals of0,2unit. 5 Apparatus Ordinary laboratory apparatus and 5.1 Platinum dish, flat-botto
37、med, approximately80mm in diameter and approximately35mm deep, fitted with a platinum lid.BS5072-5:1980 2 BSI 12-1999 5.2 Electric furnace, capable of being controlled at550 25 C. 5.3 Electric furnace, capable of being controlled at750 25 C. 5.4 pH meter, fitted with a glass measuring electrode and
38、a calomel reference electrode, sensitivity0,05pH unit. 5.5 Spectrophotometer, or 5.6 Photoelectric absorptiometer, fitted with filters giving a maximum transmission between500and520nm. 6 Procedure 6.1 Test portion Weigh, to the nearest 0,001g, 1g of the dried test sample (see ISO 3428, sub-clause2.3
39、). 6.2 Blank test Weigh into the platinum dish (5.1),12g of the sodium carbonate (4.1) and4g of the boric acid(4.2). Mix thoroughly, using a platinum spatula. Cover the dish with its lid and place in the electric furnace (5.2) controlled at 550 25 C taking care to isolate the dish from the floor of
40、the furnace by means of a support to avoid the risk of contamination. Leave the dish in the furnace until the reaction subsides. Then transfer the dish to the electric furnace (5.3) controlled at750 25 C, again isolating it from the furnace floor, and allow to remain for a maximum of5min. Remove the
41、 dish from the furnace and allow to cool in the air. Add boiling water to the dish and heat gently until dissolution is complete. After cooling slightly, transfer the contents of the dish to a beaker of suitable capacity containing20ml of the nitric acid solution (4.3). Carefully wash the dish and l
42、id with18ml of the nitric acid solution (4.3) and then with hot water, collecting the washings in the beaker, and simmer gently for a few minutes until complete dissolution is obtained. Allow to cool slightly and transfer quantitatively to a one-mark volumetric flask of the same capacity as that use
43、d for the preparation of the sample solution(6.4.1). After cooling, dilute to the mark and mix. Continue as specified in6.4.2, taking an aliquot portion equal to that taken for the determination. 6.3 Preparation of calibration graph 6.3.1 Preparation of the standard colorimetric solutions for photom
44、etric measurements carried out in cells of1cm optical path length. Into each of a series of eight100ml one-mark volumetric flasks transfer respectively the volumes of the standard iron solution (4.11) shown in the following table. Add to each flask an amount of water sufficient to dilute to approxim
45、ately 50ml, then add 5ml of the hydroxylammonium chloride solution (4.5), 5ml of the 1,10-phenanthroline solution (4.6) and 25ml of the buffer solution (4.7). Dilute to the mark and mix. 6.3.2 Photometric measurement After 10min, carry out the photometric measurement with the spectrophotometer (5.5)
46、 at a wavelength of about510nm or with the photoelectric absorptiometer (5.6) with suitable filters, after having adjusted the instrument to zero absorbance against the compensation solution. 6.3.3 Plotting of the calibration graph Plot a graph having, for example, the Fe 2 O 3content in milligrams
47、per100ml of standard colorimetric solution as abscissae and the corresponding values of absorbance as ordinates. 6.4 Determination 6.4.1 Preparation of the test solution Weigh into the platinum dish (5.1)12g of the sodium carbonate (4.1) and4g of the boric acid(4.2). Mix thoroughly using a platinum
48、spatula. Add to the mixture the test portion (6.1) and mix thoroughly. Cover the dish with its lid and place it in the electric furnace (5.2) controlled at 550 25 C, taking care to isolate the dish from the floor of the furnace by means of a support to avoid the risk of contamination. Keep at 550 25
49、 C until the reaction subsides (about 30min). Then transfer the dish to the electric furnace (5.3) controlled at 750 25 C, again taking care to isolate it from the floor of the furnace. Keep the dish in the furnace for30min, making sure that the temperature of 750 25 C is maintained for at least20min. Standard iron solution(4.11) Corresponding mass of Fe 2 O 3 ml mg 0 a 1,0 2,5 5,0 10,0 15,0 20,0 25,0 0 0,010 0,025 0,050 0,100 0,150 0,200 0,250 a Compensation solution.BS5072-5:1980 BSI 12-1999 3 Remove the dish from th
