1、INTERNATIONAL STANDARD IS0 2070 Second edition 1997-03-01 Aluminium oxide primarily used for the production of aluminium - Determination of calcium content Oxyde daluminium principalement utilis6 pour la production de Ialuminium - Dosage du calcium Reference number IS0 2070:1997(E) Copyright Interna
2、tional Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-7 1 IS0 2070:1997(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodi
3、es (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations
4、 governmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated
5、 to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 2070 was prepared by the British Standards Institution (BSI) (as BSI 4140: Part 14:1990) and was adopted under a special “fast
6、track procedure”, by Technical Committee ISO/TC 47, Chemistry, in parallel with its approval by the IS0 member bodies. It cancels and replaces IS0 2070:1981 of which it constitutes a technical revision. 0 IS0 1997 All rights reserved. Unless otherwise specified, no part of this publication may be r
7、eproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Internet centraliso.ch x.400 c=ch; a=4
8、00net; p=iso; o=isocs; s=central Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD 0 IS0 IS0 2070:1997(E) Aluminium oxide p
9、rimarily used for the production of aluminium - Determination of calcium content 1 Scope This International Standard describes a flame atomic absorption method for the determination of the calcium content of aluminium oxide primarily used for the production of aluminium. The method is applicable to
10、products having a calcium content, expressed as CaO, of not less than 0,002 % (m/m). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were
11、valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International
12、 Standards. IS0 648: 1977, Laboratory glassware - One-mark pipettes. IS0 802:1976, Aluminium oxide primarily used for the production of aluminium - Preparation and storage of test samples. IS0 1042:1983, Laboratory glassware - One-mark volumetric flasks. IS0 2073: 1976, Aluminium oxide primarily use
13、d for the production of aluminium - Preparation of solution for analysis - Method by hydrochloric acid attack under pressure. IS0 3696:1987, Water for analytical laboratory use - Specification and test methods. 3 Principle A test portion is dissolved in hydrochloric acid under pressure. The solution
14、 is aspirated into a dinitrogen oxide (nitrous oxide) acetylene flame and the calcium content determined by spectrometric measurement of the absorption at a wavelength of 422,7 nm using a calcium hollow-cathode lamp. Copyright International Organization for Standardization Provided by IHS under lice
15、nse with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 2070:1997(E) 0 IS0 4 Reagents Except where otherwise stated, use only reagents of recognized analytical grade and water complying with grade 2 of IS0 3696. Do not use leaded-glass reagent vessels. 4.1
16、Aluminium oxide, of purity greater than 99,95 %, containing less than 0,000 1 % (m/m) of CaO. 4.2 Hydrochloric acid solution, p = 1 ,I 9 g/ml, about 38 % (m/m). 4.3 Aluminium, acid solution, having an aluminium concentration equivalent to that of a 20 g/l solution of alumina (Al20a). Wash approximat
17、ely 11 g of extra-pure aluminium shavings 199,999 % (mlrrdl, in 2 ml to 3 ml of nitric acid solution p = I,4 g/ml, about 68 % hhdl. Rinse the shavings with water, wash them with acetone in a fume cupboard and blow or suck dry. Weigh, to the nearest 1 mg, 10,585 g of the dried shavings, place them in
18、 a beaker of suitable capacity (for example 500 ml and add 144 ml of hydrochloric acid solution (4.2). Add 1 drop of extra-pure mercury to aid the attack. Wait until the reaction subsides and maintain a gentle heat until all the aluminium has dissolved. Allow to cool, transfer the solution quantitat
19、ively to a 500 ml one-mark volumetric flask (5.21, dilute to the mark and mix. 4.4 Standard calcium solution, c(Ca0) = 0,020 g/l. Heat about 1 g of calcium carbonate in an oven at 110 “C L!I 5 “C for 16 h and cool in a desiccator. Weigh, to the nearest 0,000 1 g, 0,178 5 g of the calcium carbonate a
20、nd transfer to a beaker of suitable capacity (for example 100 ml) and dissolve in 5,5 ml of hydrochloric acid solution (4.2). Transfer the solution quantitatively to a 1 000 ml one-mark volumetric flask (5.21, dilute to the mark and mix. Transfer, by pipette, 100 ml of this solution to a 500 ml one-
21、mark volumetric flask (5.21, dilute to the mark and mix 4.5 Strontium chloride solution, c(SrCI.$ = 100 g/l. Weigh, to the nearest 1 mg, 25,000 g of strontium chloride of calcium content less than 0,001 % (m/m) and transfer to a beaker of suitable capacity (for example 250 ml) and dissolve in about
22、100 ml of water. Transfer the solution quantitatively to a 250 ml one-mark volumetric flask (5.21, dilute to the mark and mix. 5 Apparatus Only borosilicate glassware or plastics materials shall be used. Only ground-glass or plastic stoppers shall be used, and not rubber. Ordinary laboratory apparat
23、us, the apparatus described in 3.3.2 of IS0 802:1976, in clause 5 of IS0 2073:1976 and the following are required. 5.1 One-mark pipettes, complying with IS0 648, class A. 5.2 One-mark volumetric flasks, complying with IS0 1042, class A. 5.3 Spectrometer, atomic absorption type, fitted with a burner
24、fed from cylinders of acetylene and dinitrogen oxide (nitrous oxide), and with a calcium hollow-cathode lamp. 6 Preparation of test sample Prepare a test sample in accordance with IS0 802. 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for Resale
25、No reproduction or networking permitted without license from IHS-,-,-0 IS0 ISO2070:1997(E) 7 Procedure 7.1 Test portion Weigh, to the nearest 1 mg, 2 g of the test sample prepared in clause 6. 7.2 Determination 7.2.1 Preparation of test solution Take the test portion prepared in 7.1 and follow the p
26、rocedure described in IS0 2073. Transfer the resulting solution quantitatively to a 100 ml one-mark volumetric flask. Add, using a pipette (5.11, 5 ml of strontium chloride solution (4.5), dilute to the mark and mix. 7.2.2 Preparation of blank test solution Follow the procedure described in 7.2.1 bu
27、t replace the test portion with the same mass of aluminium oxide (4.1). weighed to the nearest 1 mg. 7.2.3 Preparation of calibration solutions Into each of a numbered series of six 100 ml one-mark volumetric flasks (5.21, transfer, using a 50 ml pipette (5.1), 50 ml of the acid solution of aluminiu
28、m (4.3) followed by the corresponding portions of the calcium solution (4.4) shown in table 1, using pipettes (5.1). Add, using a pipette (5.1), 5 ml of strontium chloride solution (4.51, dilute to the mark and mix. 7.2.4 Adjustment and operation of the spectrometer Operate the spectrometer (5.3) th
29、roughout the determination in accordance with the manufacturers instructions. Adjust the wavelength to 422,7 nm and alter the sensitivity and the aperture of the slit according to the characteristics of the instrument. Adjust the pressure of the dinitrogen oxide (nitrous oxide) and acetylene accordi
30、ng to the characteristics of the burner, to obtain an oxidizing flame. 7.2.5 Spectrometric measurements Carry out measurements at regular intervals in a random order of the test solution (see 7.2.11, the blank test solution (see 7.2.2) and the calibration solutions (see 7.2.31, taking care to mainta
31、in a constant aspiration rate. Take repeat readings of all solutions in the reverse order to compensate for drift, and calculate the mean of the duplicate absorbance values. Table 1 - Calibration solutions No. Volume of Corresponding mass of calcium solution calcium oxide ml ma 1 1) 0 0 2 5 0.10 3 I
32、O 0.20 4 15 0,30 5 20 0,40 6 25 0.50 I) Calibration blank solution. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 2070:1997(E) 8 Expression of results 8.1 Calibrati
33、on curve Correct each measurement obtained in 7.2.5 by subtracting the value given by the blank calibration solution numbered “1”. Prepare a calibration curve by plotting corrected absorbance against the corresponding mass, in milligrams, of CaO. Determine the quantities, in milligrams, of CaO corre
34、sponding to the absorbance measurements for the test solution and the blank test solution. 8.2 Calculation The calcium content W, expressed as a percentage by mass of calcium oxide (CaO), is given by the following equation: W.Jmo-“l)X 1 000 2 where mg is the mass, in milligrams, of calcium oxide fou
35、nd in the test solution; ml is the mass, in milligrams, of calcium oxide found in the blank test solution. Express the result to three decimal places. 9 Precision The precision of this method is not known because interlaboratory data are not available. Interlaboratory data are being obtained, and a
36、precision statement will be added at the next revision. 10 Test report The test report shall include the following information: a) a complete identification of the sample; b) reference to this International Standard, i.e. IS0 2070:1997; c) the results, expressed in accordance with clause 8; d) detai
37、ls of any unusual features noted during the determination; e) details of any operation not included in this International Standard or in the International Standard to whict reference is made, as well as any operation regarded as optional. 4 Copyright International Organization for Standardization Pr
38、ovided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO2070:1997(E) 0 IS0 ICS 71.100.10 Descriptors: aluminium oxide, chemical analysis, determination of content, calcium, flame photometric analysis, atomic absorption spectrometric method, extractive metallurgy. Price based on 4 pages Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
